The p53 gene,from discovery to classification:the first 10 years Forty years ago four research laboratories in London,Paris,NewYork/Bethesda,and Princeton uncovered the existence of the p53 protein (Deleo et al.,1979;...The p53 gene,from discovery to classification:the first 10 years Forty years ago four research laboratories in London,Paris,NewYork/Bethesda,and Princeton uncovered the existence of the p53 protein (Deleo et al.,1979;Lane and Crawford,1979;Linzer and Levine,1979;Kress et al.,1979).Each laboratory came upon this protein for a different reason and with a different experimental approach that uncovered this unanticipated result.Together,the four papers permitted one to con elude the following:(i) in SV40-infected and transformed cells the SV40-e ncoded on cogene protein,the large T-antigen,formed a protein complex with a cellular-encoded protein of -53000 daltons in size,(ii) This p53 protein was detected at high levels in a variety of transformed cells derived from viral,chemical,or inherited (teratocarcinomas) transformation events,(iii) Nontransformed cells expressed lower levels of the p53 protein,(iv) Animals bearing tumors produced antibodies directed against the p53 protein.展开更多
A brief review is given about the friction and wear properties of high temperature alloys. Above a critical temperature, if the oxide becomes ductile, it will flow over the surface and prevent metal-to-metat contact. ...A brief review is given about the friction and wear properties of high temperature alloys. Above a critical temperature, if the oxide becomes ductile, it will flow over the surface and prevent metal-to-metat contact. In order to study the tribology of oxide lubrication. a series of tests were carried out using Cu(ReO4)2 as a lubricant. The effects of time. Surface finish. substrates. load and temperature were investigated. A mechanism of lubrication is proposed in which the surface slip predominates along with mechanical attachment of oxide to the surface.展开更多
A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring o...A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.展开更多
The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese...The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.展开更多
The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This ano...The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This anomaly located approximately 50 km southwest of the town of Mbuji-Mayi in the Kasaï-Oriental Province in the DRC should therefore be the subject of detailed exploration with the aim of better identifying and describing this kimberlite. Thus, through exploratory work and cross-checking of geophysical and geological data, the discovery of this Massif was made by drilling on the aeromagnetic anomaly 193/172/X298. Based on drilling, sampling and laboratory petrographic analysis reports, the Boya-02 kimberlite was classified among highly diluted re-sedimented volcaniclastic kimberlites (KVR), rich in olivine and incidentally in quartz and poor in juvenile substances. This kimberlite represents a deposit of very low economic interest following extremely high dilution. The Boya-02 kimberlite was modeled using ground magnetism data. It is a complex anomaly comprising 2 components with variable amplitude appearing on a subtly magnetized linear detail. The modeled dimensions of two components of this anomaly are 0.32 Ha and 0.2 Ha at depths of 32 m & 14 m for the deposits to the West and the East respectively. Garnet data for the Boya-02 occurrence reports a maximum Pmin value of 49.7 kbar (207 garnets). These data demonstrate the high diamond potential which assumes a conductive cratonic geotherm of 40 mWm<sup>2</sup>.展开更多
Bakwanga kimberlite massive 5 in Kasai Oriental is part of a set of 13 kimberlite massives numbered according to the order in which they were discovered. They are located on an alignment with a more or less W-E direct...Bakwanga kimberlite massive 5 in Kasai Oriental is part of a set of 13 kimberlite massives numbered according to the order in which they were discovered. They are located on an alignment with a more or less W-E direction making up the Northern group known as Bakwanga. The importance of the Bakwanga kimberlite massives on the country’s economy in the production of diamonds sufficiently proves the interest of geological research work in this area. The objective of this work is to determine a mathematical model of the shape of the massive as close as possible to reality and through cartography. The cartographic study and modeling of this kimberlite massive were carried out using data from core samples taken on longitudinal and transverse profiles of the 50 × 50 meter mesh drilling plan intersecting this kimberlite massive. We intend to deduce the structure and lithostratigraphy of the kim-berlitic facies and the direct environment of massive 5. As a result, we note that the majority of surveys on the extent of this massive have intersected: Red clayey sand - Polymorphic sandstone - Nodular sandstone, with kaolin blocks and nodules - Epiclastic Kimberlite - Xenokimberlite - Massive Kimberlite - Mesozoic sandstone - Dolomite (enclosing). The shape of the Massive 5 model is vaguely elliptical with a W-E longitudinal axis of 575 m and N-S axis of 275 meters. Surveys have shown that Massive 5 is in fact composed of two pipes, located in the W (western pipe) and E (eastern pipe) ends of the massif. The two chimneys of the two pipes have walls ranging from subvertical at the eastern pipe to very steep walls of around 70˚ to 80˚ for the western pipe and the average diameter of the two pipes is ±50 meters. At level 600, the massive has an area of ±10.5 hectares and it gradually decreases in depth and the modeling of the latter shows a concentric decrease in the volume of the massive from the surface to depth in the shape of a mushroom. 3 eruptive phases established this Kimber-litic massive, the first two phases (old)展开更多
The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of...The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of the head during feeding,locomotion,predator evasion,and social interactions.Eutheria,the clade including crown placentals,has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic.Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations.A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae(C2–C7)revealing a highly modified axis(C2).The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals,muscle reconstruction,geometric morphometrics and virtual range of motion analysis.We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species(monotremes,marsupials,and placentals)using three-dimensional landmark analysis.The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals.Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size.These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.展开更多
Background: Since 2012, the World Health Organization has recommended intermittent preventive treatment with sulfadoxine-pyrimethamine (IPT-SP) to prevent malaria-related complications in pregnant women. Ten years fol...Background: Since 2012, the World Health Organization has recommended intermittent preventive treatment with sulfadoxine-pyrimethamine (IPT-SP) to prevent malaria-related complications in pregnant women. Ten years following these recommendations, we conducted this study to estimate the coverage for three doses of IPT-SP (IPT3) as well as the prevalence of low birth weight (LBW), and its associated factors in Lomé (Togo) in 2021. Methods: A cross-sectional study was conducted between January and March 2021. An exhaustive recruitment of women and their newborns was carried out in the maternity wards of the Sylvanus Olympio University Hospital Center. Data from antenatal consultations and clinical data of the newborns were collected. Multivariate logistic regression was carried out to determine factors associated with LBW. Results: A total of 252 mother-child pairs were included in this study. Median age of the mothers was 27 years, IQR [24-31]. More than a third (35.3%) of the mothers were primigravida. IPT3 coverage was 66.7% and 14.7% of newborns had a LBW. The prevalence of LBW was 33.3% [23.3-43.4] in women who had received fewer than 3 doses of IPT-SP and 5.4% [2.0-8.8] in those who had received at least 3 doses of IPT-SP (p Conclusion: Ten years following recommendations of the WHO on IPT-SP, malaria prevention based on IPT-SP is not optimal among pregnant women in Lomé, and the proportion of LBW children remains high. Actions to strengthen the three-dose IPT-SP policy are needed to prevent malaria and its consequences among newborns in Togo.展开更多
BACKGROUND: In observational studies, lower homocysteine levels are associated with lower rates of coronary heart disease and stroke. Folic acid and vitamins B6 and B12 lower homocysteine levels. We assessed whether s...BACKGROUND: In observational studies, lower homocysteine levels are associated with lower rates of coronary heart disease and stroke. Folic acid and vitamins B6 and B12 lower homocysteine levels. We assessed whether supplementation reduced the risk of major cardiovascular events in patients with vascular disease. METHODS: We randomly assigned 5522 patients 55 years of age or older who had vascular disease or diabetes to daily treatment either with the combination of 2.5 mg of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12 or with placebo for an average of five years. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, and stroke. RESULTS: Mean plasma homocysteine levels decreased by 2.4 μmol per liter(0.3 mg per liter) in the active-treatment group and increased by 0.8 μmol per liter(0.1 mg per liter) in the placebo group. Primary outcome events occurred in 519 patients(18.8 percent) assigned to active therapy and 547(19.8 percent) assigned to placebo(relative risk, 0.95; 95 percent confidence interval, 0.84 to 1.07; P=0.41). As compared with placebo, active treatment did not significantly decrease the risk of death from cardiovascular causes(relative risk, 0.96; 95 percent confidence interval, 0.81 to 1.13), myocardial infarction(relative risk, 0.98; 95 percent confidence interval, 0.85 to 1.14), or any of the secondary outcomes. Fewer patients assigned to active treatment than to placebo had a stroke(relative risk, 0.75; 95 percent confidence interval, 0.59 to 0.97). More patients in the active-treatment group were hospitalized for unstable angina(relative risk, 1.24; 95 percent confidence interval, 1.04 to 1.49). CONCLUSIONS: Supplements combining folic acid and vitamins B6 and B12 did not reduce the risk of major cardiovascular events in patients with vascular disease.展开更多
基金Canadian Institute of Health Research CCI-92216：MOP 62823国家自然科学基金资助国际合作交流项目（30811120439）（此项研究获加拿大健康研究所及皇后伊丽莎白Ⅱ健康科学基金资助+2 种基金Rockwood教授的工作受到达尔豪西医学研究基金委员会支持中加合作关系通过加拿大健康研究所及中国国家自然科学基金委员会共同联合建立,该文为此次合作的一部分特此志谢）
文摘The p53 gene,from discovery to classification:the first 10 years Forty years ago four research laboratories in London,Paris,NewYork/Bethesda,and Princeton uncovered the existence of the p53 protein (Deleo et al.,1979;Lane and Crawford,1979;Linzer and Levine,1979;Kress et al.,1979).Each laboratory came upon this protein for a different reason and with a different experimental approach that uncovered this unanticipated result.Together,the four papers permitted one to con elude the following:(i) in SV40-infected and transformed cells the SV40-e ncoded on cogene protein,the large T-antigen,formed a protein complex with a cellular-encoded protein of -53000 daltons in size,(ii) This p53 protein was detected at high levels in a variety of transformed cells derived from viral,chemical,or inherited (teratocarcinomas) transformation events,(iii) Nontransformed cells expressed lower levels of the p53 protein,(iv) Animals bearing tumors produced antibodies directed against the p53 protein.
文摘A brief review is given about the friction and wear properties of high temperature alloys. Above a critical temperature, if the oxide becomes ductile, it will flow over the surface and prevent metal-to-metat contact. In order to study the tribology of oxide lubrication. a series of tests were carried out using Cu(ReO4)2 as a lubricant. The effects of time. Surface finish. substrates. load and temperature were investigated. A mechanism of lubrication is proposed in which the surface slip predominates along with mechanical attachment of oxide to the surface.
文摘A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.
基金funding and support from the United Kingdom Space Agency(UKSA)the European Space Agency(ESA)+5 种基金funded and supported through the ESA PRODEX schemefunded through PRODEX PEA 4000123238the Research Council of Norway grant 223252funded by Spanish MCIN/AEI/10.13039/501100011033 grant PID2019-107061GB-C61funding and support from the Chinese Academy of Sciences(CAS)funding and support from the National Aeronautics and Space Administration(NASA)。
文摘The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.
文摘The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This anomaly located approximately 50 km southwest of the town of Mbuji-Mayi in the Kasaï-Oriental Province in the DRC should therefore be the subject of detailed exploration with the aim of better identifying and describing this kimberlite. Thus, through exploratory work and cross-checking of geophysical and geological data, the discovery of this Massif was made by drilling on the aeromagnetic anomaly 193/172/X298. Based on drilling, sampling and laboratory petrographic analysis reports, the Boya-02 kimberlite was classified among highly diluted re-sedimented volcaniclastic kimberlites (KVR), rich in olivine and incidentally in quartz and poor in juvenile substances. This kimberlite represents a deposit of very low economic interest following extremely high dilution. The Boya-02 kimberlite was modeled using ground magnetism data. It is a complex anomaly comprising 2 components with variable amplitude appearing on a subtly magnetized linear detail. The modeled dimensions of two components of this anomaly are 0.32 Ha and 0.2 Ha at depths of 32 m & 14 m for the deposits to the West and the East respectively. Garnet data for the Boya-02 occurrence reports a maximum Pmin value of 49.7 kbar (207 garnets). These data demonstrate the high diamond potential which assumes a conductive cratonic geotherm of 40 mWm<sup>2</sup>.
文摘Bakwanga kimberlite massive 5 in Kasai Oriental is part of a set of 13 kimberlite massives numbered according to the order in which they were discovered. They are located on an alignment with a more or less W-E direction making up the Northern group known as Bakwanga. The importance of the Bakwanga kimberlite massives on the country’s economy in the production of diamonds sufficiently proves the interest of geological research work in this area. The objective of this work is to determine a mathematical model of the shape of the massive as close as possible to reality and through cartography. The cartographic study and modeling of this kimberlite massive were carried out using data from core samples taken on longitudinal and transverse profiles of the 50 × 50 meter mesh drilling plan intersecting this kimberlite massive. We intend to deduce the structure and lithostratigraphy of the kim-berlitic facies and the direct environment of massive 5. As a result, we note that the majority of surveys on the extent of this massive have intersected: Red clayey sand - Polymorphic sandstone - Nodular sandstone, with kaolin blocks and nodules - Epiclastic Kimberlite - Xenokimberlite - Massive Kimberlite - Mesozoic sandstone - Dolomite (enclosing). The shape of the Massive 5 model is vaguely elliptical with a W-E longitudinal axis of 575 m and N-S axis of 275 meters. Surveys have shown that Massive 5 is in fact composed of two pipes, located in the W (western pipe) and E (eastern pipe) ends of the massif. The two chimneys of the two pipes have walls ranging from subvertical at the eastern pipe to very steep walls of around 70˚ to 80˚ for the western pipe and the average diameter of the two pipes is ±50 meters. At level 600, the massive has an area of ±10.5 hectares and it gradually decreases in depth and the modeling of the latter shows a concentric decrease in the volume of the massive from the surface to depth in the shape of a mushroom. 3 eruptive phases established this Kimber-litic massive, the first two phases (old)
基金supported by the National Science Centre(NCN,Kraków,Poland)(2015/18/E/NZ8/00637)the Polish National Agency for Academic Exchange(NAWA,Warszawa,Poland)(BPN/BEK/2021/1/00357/U/00001)to LFF。
文摘The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of the head during feeding,locomotion,predator evasion,and social interactions.Eutheria,the clade including crown placentals,has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic.Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations.A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae(C2–C7)revealing a highly modified axis(C2).The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals,muscle reconstruction,geometric morphometrics and virtual range of motion analysis.We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species(monotremes,marsupials,and placentals)using three-dimensional landmark analysis.The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals.Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size.These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.
文摘Background: Since 2012, the World Health Organization has recommended intermittent preventive treatment with sulfadoxine-pyrimethamine (IPT-SP) to prevent malaria-related complications in pregnant women. Ten years following these recommendations, we conducted this study to estimate the coverage for three doses of IPT-SP (IPT3) as well as the prevalence of low birth weight (LBW), and its associated factors in Lomé (Togo) in 2021. Methods: A cross-sectional study was conducted between January and March 2021. An exhaustive recruitment of women and their newborns was carried out in the maternity wards of the Sylvanus Olympio University Hospital Center. Data from antenatal consultations and clinical data of the newborns were collected. Multivariate logistic regression was carried out to determine factors associated with LBW. Results: A total of 252 mother-child pairs were included in this study. Median age of the mothers was 27 years, IQR [24-31]. More than a third (35.3%) of the mothers were primigravida. IPT3 coverage was 66.7% and 14.7% of newborns had a LBW. The prevalence of LBW was 33.3% [23.3-43.4] in women who had received fewer than 3 doses of IPT-SP and 5.4% [2.0-8.8] in those who had received at least 3 doses of IPT-SP (p Conclusion: Ten years following recommendations of the WHO on IPT-SP, malaria prevention based on IPT-SP is not optimal among pregnant women in Lomé, and the proportion of LBW children remains high. Actions to strengthen the three-dose IPT-SP policy are needed to prevent malaria and its consequences among newborns in Togo.
文摘BACKGROUND: In observational studies, lower homocysteine levels are associated with lower rates of coronary heart disease and stroke. Folic acid and vitamins B6 and B12 lower homocysteine levels. We assessed whether supplementation reduced the risk of major cardiovascular events in patients with vascular disease. METHODS: We randomly assigned 5522 patients 55 years of age or older who had vascular disease or diabetes to daily treatment either with the combination of 2.5 mg of folic acid, 50 mg of vitamin B6, and 1 mg of vitamin B12 or with placebo for an average of five years. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, and stroke. RESULTS: Mean plasma homocysteine levels decreased by 2.4 μmol per liter(0.3 mg per liter) in the active-treatment group and increased by 0.8 μmol per liter(0.1 mg per liter) in the placebo group. Primary outcome events occurred in 519 patients(18.8 percent) assigned to active therapy and 547(19.8 percent) assigned to placebo(relative risk, 0.95; 95 percent confidence interval, 0.84 to 1.07; P=0.41). As compared with placebo, active treatment did not significantly decrease the risk of death from cardiovascular causes(relative risk, 0.96; 95 percent confidence interval, 0.81 to 1.13), myocardial infarction(relative risk, 0.98; 95 percent confidence interval, 0.85 to 1.14), or any of the secondary outcomes. Fewer patients assigned to active treatment than to placebo had a stroke(relative risk, 0.75; 95 percent confidence interval, 0.59 to 0.97). More patients in the active-treatment group were hospitalized for unstable angina(relative risk, 1.24; 95 percent confidence interval, 1.04 to 1.49). CONCLUSIONS: Supplements combining folic acid and vitamins B6 and B12 did not reduce the risk of major cardiovascular events in patients with vascular disease.
