Diabatic heating by convection in the eyewall often produces an annular region of high potential vorticity(PV)around the relatively low PV eye in a strong tropical cyclone(TC).Such a PV ring is barotropically unstable...Diabatic heating by convection in the eyewall often produces an annular region of high potential vorticity(PV)around the relatively low PV eye in a strong tropical cyclone(TC).Such a PV ring is barotropically unstable and can encourage the exponential growth of PV waves.In this study,such instability and the subsequent nonlinear evolution of three TC-like vortices having PV rings with different degrees of hollowness on an f-plane are first examined using an unforced,inviscid shallow-water-equation model.Results show that the simulated eyewalls evolve similarly to those in the nondivergent barotropic model.It is also found that the polygonal eyewall structure can be decomposed into vortex Rossby waves(VRWs)of different wavenumbers with different amplitudes,allowing for wave-wave interactions to produce complicated behaviors of mesovortices in the TC eyewall.The same set of PV rings has been examined on a beta-plane.Although the beta effect has been rendered unimportant to the eyewall evolution due to the relatively small scale of the inner-core circulation,this study shows that the beta effect may erode the coherent structure of mesovortices in the eyewall of an initially hollow PV-ring vortex.Mesovortices modeled on the beta-plane with a greater beta parameter tend to experience an earlier breakdown and enhanced radial gradients of the basic-state(azimuthally mean)angular velocity,followed by wave-wave,wave-flow interactions,leading to earlier merger and axisymmetrization processes.This result implies that the beta effect could be one of the forcings that shorten the lifetime of quasi-steady mesovortices in the eyewall of real TCs.展开更多
The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the pe...The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the penetration was positively correlated with both the concentration of adjuvant and the time after application, in a given range of treatment. A synergistic effect of two types of adjuvant on the penetration was found. Some physical properties of emulsions were determined. The change of the structures of the cabbage leaf surface by these adjuvants was observed from photomicrographs. The mechanism concerned with the effect of these adjuvants on the penetration of beta- cypermethrin through the cabbage leaf surface was tentatively discussed.展开更多
BACKGROUND： Neuronal loss, synapse mutilation, and increasing malnourished axons are pathologically related to Alzheimer＇s disease. Microtubule-associated protein 2 （MAP2） is of importance for neuronal, axonal, an...BACKGROUND： Neuronal loss, synapse mutilation, and increasing malnourished axons are pathologically related to Alzheimer＇s disease. Microtubule-associated protein 2 （MAP2） is of importance for neuronal, axonal, and dendritic generation, extension, and stabilization, as well as for the regulation of synaptic plasticity. OBJECTIVE： To investigate the antagonistic effects of natural-cerebrolysin-containing serum on beta amyloid protein 1-40 （Aβ1-40）-induced neurotoxicity from the standpoints of cell proliferation, synaptogenesis, and cytoskeleton formation （MAP2 expression）. DESIGN, TIME AND SETTING： A paralleled, controlled, neural cell, and molecular biology experiment was performed at the Institute of Integrated Chinese and Western Medicine, Shenzhen Hospital, Southern Medical University between February 2006 and April 2008. MATERIALS： PC12 cells, derived from the rat central nervous system, were purchased from Shanghai Institute of Cell Biology, Chinese Academy of Sciences, China. A β1-40 was provided by Sigma, USA. Natural-cerebrolysin was provided by Shenzhen Institute of Integrated Chinese and Western Medicine, China. The natural-cerebrolysin was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae）, and Yixingye （Ginkgo Leaf） in a proportion of 1：2：2. Following conventional water extraction technology, an extract （1：20） was prepared. Each gram of extract equaled 20 grams of crude drug. In a total of 12 adult male New Zealand rabbits, six underwent intragastric administration of natural-cerebrolysin extract for 1 month to prepare natural-cerebrolysin-containing serum, and the remaining six rabbits received intragastric administration of physiological saline to prepare normal blank serum. METHODS： An AIzheimer＇s disease in vitro model was induced in PC12 cells using Aβ1-40. The cells were incubated with varying doses of natural-cerebrolysin-containing serum （2.5%, 5%, and 10%）. Normal blank serum-treated PC12 cells served as a blank control group. MAIN OUTCOME MEASURES： Through the use of inverted phase contrast microscope, cell morphology and neurite growth were observed, neurite length was measured, and the percentage of neurite-positive cells was calculated. Cell proliferation rate was determined by MTT assay, and MAP 2 expression was detected by fluorescent immunocytochemistry. RESULTS： Following Aβ1-40 treatments, some PC12 cells were apoptotic/dying, and only a few short neurites were observed. Following interventions with natural-cerebrolysin-containing serum, the PC12 cells proliferated, there was an increased number of neurites, and neurite length was enhanced. After middle- and high-dose natural-cerebrolysin treatments, the percentage of neurite-positive cells, as well as the average length of neurites, was significantly greater than the normal blank serum-treated PC12 cells （P 〈 0.05 or P 〈 0.01）. Compared with the blank control group, MAP2 expression in the Aβ1-40-treated PC12 cells was significantly inhibited, and the cell proliferation rate was significantly decreased （P 〈 0.01）. Following incubations with natural-cerebrolysin-containing serum, MAP2 expression and cell proliferation rate in the PC12 cells were significantly increased in a dose-dependent manner, compared with treatments with blank control serum （P 〈 0.05 or P 〈 0.01 ）. CONCLUSION： Natural-cerebrolysin exhibited antagonistic effects on neurotoxicity in Aβ1-40 induced Alzheimer＇s disease in vitro models. These effects were likely related to cell proliferation and the upregulation of intracellular MAP2 expression.展开更多
In order to assess public effective dose due to gross alpha and beta in water, 43 tap water samples were collected from different areas in the District of Abidjan. Using the low background Gas-less Automatic Alpha/Bet...In order to assess public effective dose due to gross alpha and beta in water, 43 tap water samples were collected from different areas in the District of Abidjan. Using the low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) for analysis, the gross alpha and beta concentrations found varied from 0.001 ± 0.002 to 0.063 ± 0.050 Bq/l with an average of 0.013 ± 0.012 Bq/l and from 0.067 ± 0.080 to 0.320 ± 0.120 Bq/l with an average of 0.174 ± 0.076 Bq/l, respectively in samples. The public effective dose assessment showed values of dose to ingestion of alpha and beta emitter radionuclides lower than the recommended value of dose for drinking water 0.1 mSv/y, except in 30% of the samples. These results show the need for additional studies to be conducted in order to clarify the hazardousness of these water samples. However, this study still remains important because it has provided necessary data for future tap water quality monitoring studies in the District of Abidjan.展开更多
Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the ...Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.展开更多
BACKGROUND： Studies have demonstrated that β-amyloid peptide （Aβ）, a characteristic pathological product of Alzheimer＇s disease （AD）, results in neuronal endoplasmic reticulum stress （ERS）. However, the mech...BACKGROUND： Studies have demonstrated that β-amyloid peptide （Aβ）, a characteristic pathological product of Alzheimer＇s disease （AD）, results in neuronal endoplasmic reticulum stress （ERS）. However, the mechanisms of traditional Chinese medicine against ERS in AD are poorly understood. OBJECTIVE： To measure expression levels of protective proteins （GRP78 and GRP94） of ER molecular partners and pro-apoptotic Caspase-12 ER membrane expression following application of traditional Chinese medicine natural cerebrolysin （NC） to treat Aβ1-40-induced ERS. DESIGN, TIME AND SETTING： A parallel-controlled study was performed at the Institute of Integrated Western and Traditional Chinese Medicine, Shenzhen Hospital of Southern Medical University between September 2006 and November 2008. MATERIALS： Sprague Dawley male rats, 6-8 weeks old, were used to harvest tibial and femoral bone marrow. Isolation and purification of mesenchymal stem cells （MSCs） were established from the whole bone marrow by removing non-adherent cells in primary and passage cultures. Aβ1-40 was provided by Sigma, USA. NC was provided by Shenzhen Institute of Integrated Chinese and Western Medicine, China. NC was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae）, and Yinxingye （Ginkgo Leaf） in a proportion of 1 ： 2： 2. Following conventional water extraction technology, an extract （1 ： 20） was prepared. Six adult, male, New Zealand rabbits underwent intragastric administration of NC extract （0.976 g/kg per day） for 1 month to prepare NC-positive serum, and the remaining 6 rabbits received intragastric administration of physiological saline to prepare normal blank serum. METHODS： A total of 500 nmol/L Aβ1-40 was used to establish ERS models of primary cultured MSCs. AD cell models were incubated with different doses of NC-positive serum （2.5%, 5%, and 10%）. MSCs treated with normal blank serum served as normal blank controls. MAIN OUTCOME MEASURES： Reverse transcription-polymerase chain reaction and fluorescent immunocytochemistry were respectively used to measure mRNA and protein expression levels of GRP78, GRP94, and Caspase-12 in MSCs. RESULTS： Following Aβ1-40 exposure, mRNA and protein expression levels of GRP78 and GRP94, as well as Caspase-12, significantly increased （P 〈 0.05）, suggesting successful establishment of ERS models. Following NC-positive serum application, mRNA and protein expression levels of GRP78 and GRP94 in MSCs significantly increased （P 〈 0.05 or P 〈 0.01）. However, mRNA and protein expression levels of Caspase-12 significantly decreased （P 〈 0.05, or P 〈 0.01） compared with the ERS model group. These effects were dose-dependent. CONCLUSION： NC downregulated Caspase-12 expression and upregulated GRP78 and GRP94 expression in MSCs in a dose-dependent manner under the state of Aβ1-40-induced ERS.展开更多
Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries,in which 0.101121 Ci 63Ni was selected as the beta source.The time-related electrical properties were o...Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries,in which 0.101121 Ci 63Ni was selected as the beta source.The time-related electrical properties were obtained using Monte Carlo simulations.For the n-type ZnO,the Pt/ZnO Schottky diode had the highest energy conversion efficiency,and the Ni/ZnO Schottky diode had the largest Isc.The overall electrical performance of PN junctions is better than that of Schottky diodes.The lifetimes of Pt/ZnO and Ni/ZnO are longer than for other Schottky devices,coming close to those of PN junctions.Considering that Schottky diodes are easier to fabricate and independent of p-type semiconductors,Pt/ZnO and Ni/ZnO diodes offer alternatives to PN-junction-based betavoltaic batteries.展开更多
Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci^(63) Ni and 8 Ci^(147) Pm are used as the beta sources. Based on a Monte Carlo simulation,...Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci^(63) Ni and 8 Ci^(147) Pm are used as the beta sources. Based on a Monte Carlo simulation, the full scales of the devices are derived as 17 and 118 lm,respectively, for both sources. The influences of semiconductor doping concentrations on the electrical properties of the devices are analyzed. For a typical doping concentration N_A= 10^(17) cm^(-3), N_D= 10^(16) cm^(-3), the conversion efficiencies are 7.177% and 1.658%, respectively, using63 Ni and147 Pm sources. The calculation results of energy deposition in materials for the two sources show that the doping concentrations drop to 1 × 10^(13)–5×10^(14) cm^(-3) and 1 × 10^(12)–5×10^(13), and accordingly, the energy conversion efficiencies rise to 14.212% and 18.359%, respectively.展开更多
Previous studies have confirmed that telencephalin （TLN） is a neural glycoprotein that protects axonal disruption induced by the beta-amyloid protein （Aβ42/35） in the neural crest-derived tumor cell line Paju. Th...Previous studies have confirmed that telencephalin （TLN） is a neural glycoprotein that protects axonal disruption induced by the beta-amyloid protein （Aβ42/35） in the neural crest-derived tumor cell line Paju. The present study investigated the effects of TLN on neuronal degeneration induced by Aβ42 in the differentiated Paju cell line. Results demonstrated that after cultivating cells in Aβ42 medium, the survival rate of Paju-TLN cells was significantly higher than that of Paju-neo cells, and that apoptotic rate was noticeably reduced. These results indicate that TLN reduces Paju cell apoptosis induced by Aβ42.展开更多
The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/A...The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/Al2O3 ratios of 25 and 75.In order to affect the strength and distribution of the acidic sites, as well as the mobility of NH4^+ ions in the zeolites cages, a secondary level of porosity was introduced in the NH4^+-Beta, presenting a different stability versus alkaline treatment, by using a thermal or an ultrasound assisted method.By analyzing the catalytic behavior in these two series of samples with respect to the changes in porosity by nonlocal density functional theory, structure by XRD, amount of acid sites by FT-IR and mobility of NH4^+ cations by measurements of reversible NH4^+ exchange capacity, was evidenced a decrease in catalytic performances both in terms of rate of HMF depletion and productivity to the main products, when confinement of the ammonium ions is lost due to the introduction of mesoporosity.The high capability of ammonium ions release, associated to the mono-dentate configuration,and the minor confinement effect inside the zeolite pore system, due to the more opened pores structure of mesoporous zeolites, hinders both the direct etherification of HMF to EMF [5-(ethoxymethyl)furan-2-carbaldehyde] and the parallel reaction pathway via acetalization, favoring the rapid desorption of the HMFDEA [5-(hydroxymethyl)furfural diethyl acetal] product out of the crystal and the consequent inhibition of the consecutive reactions to EMFDEA [5-(ethoxymethyl)furfural diethyl acetal] and EMF.展开更多
AIMS To assess the protective effect of diallyl disulfide (DADS) and its combined use with N-acetyl-cysteine (NAC) on acetaminophen (APAP) hepatotoxicity in C57BL/6N (B6) mice pretreated with β naphthoflavone (BN...AIMS To assess the protective effect of diallyl disulfide (DADS) and its combined use with N-acetyl-cysteine (NAC) on acetaminophen (APAP) hepatotoxicity in C57BL/6N (B6) mice pretreated with β naphthoflavone (BNF). METHODS B6 mice were divided into six groups and all compounds used were injected intraperitoneally. Except for control and APAP group (receiving APAP only), the other groups received an injection of APAP (350mg/kg) 48 hours after BNF (200mg/kg) and either of DADS (200mg/kg), or NAC (500mg/kg) or both DADS and NAC. DADS was given 2 hours before APAP and NAC was injected with APAP. The mean survival time was recorded and livers were examined histologically. Hepatic glutathione (GSH) levels and plasma ALT were also determined at different time points. To evaluate the effect of DADS or NAC on hepatic P450 induction by BNF, liver microsomes were prepared and 7 ethoxyresorufin O dealkylase (ERD) activity was determined using spectrofluorometrical methods. In vitro effect of DADS or NAC on ERD activity was assayed by directly incubating microsomal suspension with DADS or NAC of different concentrations. RESULTS APAP was not toxic to mice without BNF pretreatment, but caused severe liver necrosis and death of all BNF treated mice in 4 hours. A sharp depletion of GSH (approximately 62% of its initial content at 2 hours and 67% at 4 hours) and a linear elevation of ALT levels (536 8±29 5 Sigma units at 2 hours and 1302 5±74 9 at 4 hours) were observed. DADS and NAC given individually produced mild protection, resulting in prolonged survival, a slower decline of GSH level and a less steeper elevation of ALT level. All mice died eventually. Co administration of DADS and NAC completely protected mice. GSH level in this group lowered by about 35% and 30% at 2 and 4 hours, and ALT was 126±18 and 157 5±36 6 Sigma units at 2 and 4 hours. ERD activity in BNF treated mice was about 5 times that of the constitutive level determined in normal mice. Neither DADS nor NAC inhibited P450 1A1/1A2 induction as determined by their effect on the induction of ERD activity. In vitro assay indicates that DADS, but not NAC, was a potent inhibitor of ERD activity (IC 50 =4 6μM). CONCLUSIONS A combined use of both DADS and NAC produced full protection in BNF treated mice against APAP hepatotoxicity. The mechanism is that DADS inhibits P450 1A1/1A2 activity, but not induction, which substantially reduces production of NAPQI, while NAC enhances liver detoxifying capability via serving as a precursor of GSH and stimulating GSH synthesis.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant No.41730960in part by NSF grant AGS-1834300。
文摘Diabatic heating by convection in the eyewall often produces an annular region of high potential vorticity(PV)around the relatively low PV eye in a strong tropical cyclone(TC).Such a PV ring is barotropically unstable and can encourage the exponential growth of PV waves.In this study,such instability and the subsequent nonlinear evolution of three TC-like vortices having PV rings with different degrees of hollowness on an f-plane are first examined using an unforced,inviscid shallow-water-equation model.Results show that the simulated eyewalls evolve similarly to those in the nondivergent barotropic model.It is also found that the polygonal eyewall structure can be decomposed into vortex Rossby waves(VRWs)of different wavenumbers with different amplitudes,allowing for wave-wave interactions to produce complicated behaviors of mesovortices in the TC eyewall.The same set of PV rings has been examined on a beta-plane.Although the beta effect has been rendered unimportant to the eyewall evolution due to the relatively small scale of the inner-core circulation,this study shows that the beta effect may erode the coherent structure of mesovortices in the eyewall of an initially hollow PV-ring vortex.Mesovortices modeled on the beta-plane with a greater beta parameter tend to experience an earlier breakdown and enhanced radial gradients of the basic-state(azimuthally mean)angular velocity,followed by wave-wave,wave-flow interactions,leading to earlier merger and axisymmetrization processes.This result implies that the beta effect could be one of the forcings that shorten the lifetime of quasi-steady mesovortices in the eyewall of real TCs.
基金spported by National Science Foundation of China(No.29873055)..
文摘The effects of three types of adjuvant (mineral oil, higher aliphatic acid and nonionic surfactant) on the penetration of beta-cypermethrin through the cabbage leaf surface were studied. The results showed that the penetration was positively correlated with both the concentration of adjuvant and the time after application, in a given range of treatment. A synergistic effect of two types of adjuvant on the penetration was found. Some physical properties of emulsions were determined. The change of the structures of the cabbage leaf surface by these adjuvants was observed from photomicrographs. The mechanism concerned with the effect of these adjuvants on the penetration of beta- cypermethrin through the cabbage leaf surface was tentatively discussed.
基金Supported by:Scientific and Technological Foundation of the National Administration of Traditional Chinese Medicine of China,No.02-03LP41the Scientific and Technological Key Project of Guangdong Province,No. 2006B35630007
文摘BACKGROUND： Neuronal loss, synapse mutilation, and increasing malnourished axons are pathologically related to Alzheimer＇s disease. Microtubule-associated protein 2 （MAP2） is of importance for neuronal, axonal, and dendritic generation, extension, and stabilization, as well as for the regulation of synaptic plasticity. OBJECTIVE： To investigate the antagonistic effects of natural-cerebrolysin-containing serum on beta amyloid protein 1-40 （Aβ1-40）-induced neurotoxicity from the standpoints of cell proliferation, synaptogenesis, and cytoskeleton formation （MAP2 expression）. DESIGN, TIME AND SETTING： A paralleled, controlled, neural cell, and molecular biology experiment was performed at the Institute of Integrated Chinese and Western Medicine, Shenzhen Hospital, Southern Medical University between February 2006 and April 2008. MATERIALS： PC12 cells, derived from the rat central nervous system, were purchased from Shanghai Institute of Cell Biology, Chinese Academy of Sciences, China. A β1-40 was provided by Sigma, USA. Natural-cerebrolysin was provided by Shenzhen Institute of Integrated Chinese and Western Medicine, China. The natural-cerebrolysin was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae）, and Yixingye （Ginkgo Leaf） in a proportion of 1：2：2. Following conventional water extraction technology, an extract （1：20） was prepared. Each gram of extract equaled 20 grams of crude drug. In a total of 12 adult male New Zealand rabbits, six underwent intragastric administration of natural-cerebrolysin extract for 1 month to prepare natural-cerebrolysin-containing serum, and the remaining six rabbits received intragastric administration of physiological saline to prepare normal blank serum. METHODS： An AIzheimer＇s disease in vitro model was induced in PC12 cells using Aβ1-40. The cells were incubated with varying doses of natural-cerebrolysin-containing serum （2.5%, 5%, and 10%）. Normal blank serum-treated PC12 cells served as a blank control group. MAIN OUTCOME MEASURES： Through the use of inverted phase contrast microscope, cell morphology and neurite growth were observed, neurite length was measured, and the percentage of neurite-positive cells was calculated. Cell proliferation rate was determined by MTT assay, and MAP 2 expression was detected by fluorescent immunocytochemistry. RESULTS： Following Aβ1-40 treatments, some PC12 cells were apoptotic/dying, and only a few short neurites were observed. Following interventions with natural-cerebrolysin-containing serum, the PC12 cells proliferated, there was an increased number of neurites, and neurite length was enhanced. After middle- and high-dose natural-cerebrolysin treatments, the percentage of neurite-positive cells, as well as the average length of neurites, was significantly greater than the normal blank serum-treated PC12 cells （P 〈 0.05 or P 〈 0.01）. Compared with the blank control group, MAP2 expression in the Aβ1-40-treated PC12 cells was significantly inhibited, and the cell proliferation rate was significantly decreased （P 〈 0.01）. Following incubations with natural-cerebrolysin-containing serum, MAP2 expression and cell proliferation rate in the PC12 cells were significantly increased in a dose-dependent manner, compared with treatments with blank control serum （P 〈 0.05 or P 〈 0.01 ）. CONCLUSION： Natural-cerebrolysin exhibited antagonistic effects on neurotoxicity in Aβ1-40 induced Alzheimer＇s disease in vitro models. These effects were likely related to cell proliferation and the upregulation of intracellular MAP2 expression.
文摘In order to assess public effective dose due to gross alpha and beta in water, 43 tap water samples were collected from different areas in the District of Abidjan. Using the low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) for analysis, the gross alpha and beta concentrations found varied from 0.001 ± 0.002 to 0.063 ± 0.050 Bq/l with an average of 0.013 ± 0.012 Bq/l and from 0.067 ± 0.080 to 0.320 ± 0.120 Bq/l with an average of 0.174 ± 0.076 Bq/l, respectively in samples. The public effective dose assessment showed values of dose to ingestion of alpha and beta emitter radionuclides lower than the recommended value of dose for drinking water 0.1 mSv/y, except in 30% of the samples. These results show the need for additional studies to be conducted in order to clarify the hazardousness of these water samples. However, this study still remains important because it has provided necessary data for future tap water quality monitoring studies in the District of Abidjan.
文摘Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan.
基金the National Natural Science Foundation of China, No. 30973779the National Special Planning Project for Traditional Chinese Medicine of China, No.02-03LP41the Key Program of Scientific Planning of Guangdong Province, No. 2006B35630007
文摘BACKGROUND： Studies have demonstrated that β-amyloid peptide （Aβ）, a characteristic pathological product of Alzheimer＇s disease （AD）, results in neuronal endoplasmic reticulum stress （ERS）. However, the mechanisms of traditional Chinese medicine against ERS in AD are poorly understood. OBJECTIVE： To measure expression levels of protective proteins （GRP78 and GRP94） of ER molecular partners and pro-apoptotic Caspase-12 ER membrane expression following application of traditional Chinese medicine natural cerebrolysin （NC） to treat Aβ1-40-induced ERS. DESIGN, TIME AND SETTING： A parallel-controlled study was performed at the Institute of Integrated Western and Traditional Chinese Medicine, Shenzhen Hospital of Southern Medical University between September 2006 and November 2008. MATERIALS： Sprague Dawley male rats, 6-8 weeks old, were used to harvest tibial and femoral bone marrow. Isolation and purification of mesenchymal stem cells （MSCs） were established from the whole bone marrow by removing non-adherent cells in primary and passage cultures. Aβ1-40 was provided by Sigma, USA. NC was provided by Shenzhen Institute of Integrated Chinese and Western Medicine, China. NC was predominantly composed of Renshen （Radix Ginseng）, Tianma （Rhizoma Gastrodiae）, and Yinxingye （Ginkgo Leaf） in a proportion of 1 ： 2： 2. Following conventional water extraction technology, an extract （1 ： 20） was prepared. Six adult, male, New Zealand rabbits underwent intragastric administration of NC extract （0.976 g/kg per day） for 1 month to prepare NC-positive serum, and the remaining 6 rabbits received intragastric administration of physiological saline to prepare normal blank serum. METHODS： A total of 500 nmol/L Aβ1-40 was used to establish ERS models of primary cultured MSCs. AD cell models were incubated with different doses of NC-positive serum （2.5%, 5%, and 10%）. MSCs treated with normal blank serum served as normal blank controls. MAIN OUTCOME MEASURES： Reverse transcription-polymerase chain reaction and fluorescent immunocytochemistry were respectively used to measure mRNA and protein expression levels of GRP78, GRP94, and Caspase-12 in MSCs. RESULTS： Following Aβ1-40 exposure, mRNA and protein expression levels of GRP78 and GRP94, as well as Caspase-12, significantly increased （P 〈 0.05）, suggesting successful establishment of ERS models. Following NC-positive serum application, mRNA and protein expression levels of GRP78 and GRP94 in MSCs significantly increased （P 〈 0.05 or P 〈 0.01）. However, mRNA and protein expression levels of Caspase-12 significantly decreased （P 〈 0.05, or P 〈 0.01） compared with the ERS model group. These effects were dose-dependent. CONCLUSION： NC downregulated Caspase-12 expression and upregulated GRP78 and GRP94 expression in MSCs in a dose-dependent manner under the state of Aβ1-40-induced ERS.
基金supported by the National Major Scientific Instruments and Equipment Development Projects(No.2012YQ240121)National Natural Science Foundation of China(No.11075064)
文摘Schottky diodes and PN junctions were utilized as energy converting structures in ZnO-based betavoltaic batteries,in which 0.101121 Ci 63Ni was selected as the beta source.The time-related electrical properties were obtained using Monte Carlo simulations.For the n-type ZnO,the Pt/ZnO Schottky diode had the highest energy conversion efficiency,and the Ni/ZnO Schottky diode had the largest Isc.The overall electrical performance of PN junctions is better than that of Schottky diodes.The lifetimes of Pt/ZnO and Ni/ZnO are longer than for other Schottky devices,coming close to those of PN junctions.Considering that Schottky diodes are easier to fabricate and independent of p-type semiconductors,Pt/ZnO and Ni/ZnO diodes offer alternatives to PN-junction-based betavoltaic batteries.
基金supported by the National Major Scientific Instruments and Equipment Development Projects(No.2012YQ240121)the National Natural Science Foundation of China(No.11075064)
文摘Third-generation-semiconductor zinc oxide is utilized as an energy converting material in a betavoltaic battery, where 0.06 Ci^(63) Ni and 8 Ci^(147) Pm are used as the beta sources. Based on a Monte Carlo simulation, the full scales of the devices are derived as 17 and 118 lm,respectively, for both sources. The influences of semiconductor doping concentrations on the electrical properties of the devices are analyzed. For a typical doping concentration N_A= 10^(17) cm^(-3), N_D= 10^(16) cm^(-3), the conversion efficiencies are 7.177% and 1.658%, respectively, using63 Ni and147 Pm sources. The calculation results of energy deposition in materials for the two sources show that the doping concentrations drop to 1 × 10^(13)–5×10^(14) cm^(-3) and 1 × 10^(12)–5×10^(13), and accordingly, the energy conversion efficiencies rise to 14.212% and 18.359%, respectively.
文摘Previous studies have confirmed that telencephalin （TLN） is a neural glycoprotein that protects axonal disruption induced by the beta-amyloid protein （Aβ42/35） in the neural crest-derived tumor cell line Paju. The present study investigated the effects of TLN on neuronal degeneration induced by Aβ42 in the differentiated Paju cell line. Results demonstrated that after cultivating cells in Aβ42 medium, the survival rate of Paju-TLN cells was significantly higher than that of Paju-neo cells, and that apoptotic rate was noticeably reduced. These results indicate that TLN reduces Paju cell apoptosis induced by Aβ42.
文摘The role of NH4^+ ion confinement in the catalytic etherification of HMF(5-hydroxymethylfurfural) with ethanol to biodiesel additives was evidenced by studying the catalytic behavior of NH4^+-Beta zeolites with SiO2/Al2O3 ratios of 25 and 75.In order to affect the strength and distribution of the acidic sites, as well as the mobility of NH4^+ ions in the zeolites cages, a secondary level of porosity was introduced in the NH4^+-Beta, presenting a different stability versus alkaline treatment, by using a thermal or an ultrasound assisted method.By analyzing the catalytic behavior in these two series of samples with respect to the changes in porosity by nonlocal density functional theory, structure by XRD, amount of acid sites by FT-IR and mobility of NH4^+ cations by measurements of reversible NH4^+ exchange capacity, was evidenced a decrease in catalytic performances both in terms of rate of HMF depletion and productivity to the main products, when confinement of the ammonium ions is lost due to the introduction of mesoporosity.The high capability of ammonium ions release, associated to the mono-dentate configuration,and the minor confinement effect inside the zeolite pore system, due to the more opened pores structure of mesoporous zeolites, hinders both the direct etherification of HMF to EMF [5-(ethoxymethyl)furan-2-carbaldehyde] and the parallel reaction pathway via acetalization, favoring the rapid desorption of the HMFDEA [5-(hydroxymethyl)furfural diethyl acetal] product out of the crystal and the consequent inhibition of the consecutive reactions to EMFDEA [5-(ethoxymethyl)furfural diethyl acetal] and EMF.
文摘AIMS To assess the protective effect of diallyl disulfide (DADS) and its combined use with N-acetyl-cysteine (NAC) on acetaminophen (APAP) hepatotoxicity in C57BL/6N (B6) mice pretreated with β naphthoflavone (BNF). METHODS B6 mice were divided into six groups and all compounds used were injected intraperitoneally. Except for control and APAP group (receiving APAP only), the other groups received an injection of APAP (350mg/kg) 48 hours after BNF (200mg/kg) and either of DADS (200mg/kg), or NAC (500mg/kg) or both DADS and NAC. DADS was given 2 hours before APAP and NAC was injected with APAP. The mean survival time was recorded and livers were examined histologically. Hepatic glutathione (GSH) levels and plasma ALT were also determined at different time points. To evaluate the effect of DADS or NAC on hepatic P450 induction by BNF, liver microsomes were prepared and 7 ethoxyresorufin O dealkylase (ERD) activity was determined using spectrofluorometrical methods. In vitro effect of DADS or NAC on ERD activity was assayed by directly incubating microsomal suspension with DADS or NAC of different concentrations. RESULTS APAP was not toxic to mice without BNF pretreatment, but caused severe liver necrosis and death of all BNF treated mice in 4 hours. A sharp depletion of GSH (approximately 62% of its initial content at 2 hours and 67% at 4 hours) and a linear elevation of ALT levels (536 8±29 5 Sigma units at 2 hours and 1302 5±74 9 at 4 hours) were observed. DADS and NAC given individually produced mild protection, resulting in prolonged survival, a slower decline of GSH level and a less steeper elevation of ALT level. All mice died eventually. Co administration of DADS and NAC completely protected mice. GSH level in this group lowered by about 35% and 30% at 2 and 4 hours, and ALT was 126±18 and 157 5±36 6 Sigma units at 2 and 4 hours. ERD activity in BNF treated mice was about 5 times that of the constitutive level determined in normal mice. Neither DADS nor NAC inhibited P450 1A1/1A2 induction as determined by their effect on the induction of ERD activity. In vitro assay indicates that DADS, but not NAC, was a potent inhibitor of ERD activity (IC 50 =4 6μM). CONCLUSIONS A combined use of both DADS and NAC produced full protection in BNF treated mice against APAP hepatotoxicity. The mechanism is that DADS inhibits P450 1A1/1A2 activity, but not induction, which substantially reduces production of NAPQI, while NAC enhances liver detoxifying capability via serving as a precursor of GSH and stimulating GSH synthesis.
