Objective A new technique of transthoracic lung ultrasonography(TLS) has emerged and demonstrated promising results in acute heart failure diagnosis at an early stage. However, the diagnostic value of ultrasound lung ...Objective A new technique of transthoracic lung ultrasonography(TLS) has emerged and demonstrated promising results in acute heart failure diagnosis at an early stage. However, the diagnostic value of ultrasound lung comets(ULCs) for acute heart failure(AHF) performed in busy emergency department(ED) is uncertain. The present meta-analysis aimed to assess the diagnostic efficiency of ULCs in AHF. Methods We conducted a search on online journal databases to collect the data on TLS performed for diagnosing AHF published up to the end of July 2017. The sensitivity, specificity, positive likelihood ratio(PLR), negative likelihood ratio(NLR), and summary receiver operating characteristic(SROC) curve were calculated. The post-test probability of AHF was calculated by using Bayes analysis. Results We enrolled a total of 15 studies involving 3,309 patients. The value of sensitivity, specificity, PLR, NLR, DOR, area under the SROC curve, and Q* index was 85%, 91%, 8.94, 0.14, 67.24, 0.9587, and 0.9026, respectively. We detected significant heterogeneity among included studies, and therefore, all these results were analyzed under the random-effect model. We also explored possible sources of heterogeneity among the studies by using meta-regression analysis. Results suggest that the time interval between patient's admission to bedside TLS examination was closely related to TLS accuracy. Conclusion This meta-analysis demonstrated that detecting ULCs is a convenient bedside tool and has high accuracy for early AHF diagnosis in ED. TLS could be recommended to be applied for early diagnosis of AHF in ED.展开更多
SUISEI is a suite of computational tools that has been developed over the past three decades and successfully applied to comets;including ComChem, a global, multi-fluid gas dynamics simulation with detailed chemical k...SUISEI is a suite of computational tools that has been developed over the past three decades and successfully applied to comets;including ComChem, a global, multi-fluid gas dynamics simulation with detailed chemical kinetics of the cometary coma;ComDust, a model of comet dust evolution and interaction with gas;and ComNuc, a 3-D simulation of gas and heat flow within the comet nucleus porous subsurface layers. The combination of these tools have resulted in an improved knowledge of chemical species in the comet’s coma and their relationship to native molecules in the nucleus ices by analyzing space- and ground-based observations and in situ measurements from spacecraft missions. A review of SUISEI is presented and applications are made to two cases: chemical recycling of HCN in comets and the physical conditions of the near-Sun object, 3200 Phaethon.展开更多
Since the concept of Nongravitational Force (hereafter NF) was first proposed a century and a half ago, different models of it have been suggested and being modified. Its effect on the orbital motions of comets has be...Since the concept of Nongravitational Force (hereafter NF) was first proposed a century and a half ago, different models of it have been suggested and being modified. Its effect on the orbital motions of comets has been studied. Especially, some researchers have attempted to draw some inclues of the physical nature of the cometary nucleus from the NF parameters. In this paper, we try to give a concise review about the different models of NF and their effects on orbit computation. And then, we will try to detect whether there is nongravitational effect on Comet Hale-Bopp’s orbital motion using Style II NF model.展开更多
Although people have studied comets for a long time and used spacecraft to detect comets in a short distance,the formation time and causes of comets are still unresolved.Therefore,according to the formation and evolut...Although people have studied comets for a long time and used spacecraft to detect comets in a short distance,the formation time and causes of comets are still unresolved.Therefore,according to the formation and evolution law of planets and the dynamic mechanism,the author thoroughly revealed the formation and evolution of comets:A powerful storm cyclone on Neptune,such as the Great Dark Spot,can involve a large number of clouds.These clouds are gradually cooled and compressed in the process of rapidly sinking along the spiral path,and then condense into huge water ice crystals at the bottom of the cyclone;When such a crystal falls into a deep hole filled with liquid hydrogen,it is easy to collide violently with the boulders in the hole,and instantly ignite the liquid hydrogen in the hole.Under the strong push of high-pressure gas,some fragments of the ice crystal can quickly reach a very high initial speed.Especially when the jet direction of the Great Dark Spot is consistent with the direction of Neptune’s revolution speed,such fragments can quickly reach Neptune’s escape speed of 23.56 km/s.Therefore,the fragments can break away from Neptune and enter an elliptical orbit around the sun,becoming a comet.Similarly,when the metal hydrogen at the bottom of a Great Red Spot on Jupiter explodes in a series,the fragments ejected from the Great Red Spot can reach the escape speed of Jupiter of 60 km/s,therefore,such fragments can break away from Jupiter and enter the elliptical orbit around the sun to become comets.Many of these comets can become asteroids in the asteroid belt,which is the formation principle of the asteroid belt.展开更多
If you happen to gaze up in the sky at just the right time in the year 2061,you might get to see one of the most famous comets of all.It's called Halley's Comet,and people get a chance to see it every 76years ...If you happen to gaze up in the sky at just the right time in the year 2061,you might get to see one of the most famous comets of all.It's called Halley's Comet,and people get a chance to see it every 76years when the comets orbit brings it close to the Earth.展开更多
Background:The analysis of chromatin integrity has become an important determinant of sperm quality.In frozenthawed bovine sperm,neither the sequence of post-thaw injury events nor the dynamics of different types of s...Background:The analysis of chromatin integrity has become an important determinant of sperm quality.In frozenthawed bovine sperm,neither the sequence of post-thaw injury events nor the dynamics of different types of sperm DNA breaks are well understood.The aim of the present work was to describe such sperm degradation aftermath focusing on DNA damage dynamics,and to assess if this parameter can predict pregnancy rates in cattle.Results:A total of 75 cryopreserved ejaculates from 25 Holstein bulls were evaluated at two post-thawing periods(0-2 h and 2-4 h),analyzing global and double-stranded DNA damage through alkaline and neutral Comet assays,chromatin deprotamination and decondensation,sperm motility,viability,acrosomal status,and intracellular levels of total ROS,superoxides and calcium.Insemination of 59,605 females was conducted using sperm from the same bulls,thus obtaining the non-return to estrus rates after 90 d(NRR).Results showed an increased rate of double-stranded breaks in the first period(0-2 h:1.29±1.01%/h vs.2-4 h:0.13±1.37%/h;P<0.01),whereas the rate of sperm with moderate+high single-stranded breaks was higher in the second period(0-2 h:3.52±7.77%/h vs.2-4h:21.06±11.69%/h;P<0.0001).Regarding sperm physiology,viability decrease rate was different between the two periods(0-2 h:-4.49±1.79%/h vs.2-4 h:-2.50±3.39%/h;P=0.032),but the progressive motility decrease rate was constant throughout post-thawing incubation(0-2 h:-4.70±3.42%/h vs.2-4 h:-1.89±2.97%/h;P>0.05).Finally,whereas no correlations between bull fertility and any dynamic parameter were found,there were correlations between the NRR and the basal percentage of highly-damaged sperm assessed with the alkaline Comet(Rs=-0.563,P=0.003),between NRR and basal progressive motility(Rs=0.511,P=0.009),and between NRR and sperm with high ROS at 4 h post-thaw(Rs=0.564,P=0.003).Conclusion:The statistically significant correlations found between intracellular ROS,sperm viability,sperm motility,DNA damage and chromatin deprotamination suggested a sequence of events all driven by oxidative stress,where viability and motility would be affected first and sperm chromatin would be altered at a later stage,thus suggesting that bovine sperm should be used for fertilization within 2 h post-thaw.Fertility correlations supported that the assessment of global DNA damage through the Comet assay may help predict bull fertility.展开更多
Despite Pluto’s demotion to dwarf planet status,people are still attached to it.Scientists combined observations of Pluto from NASA’s New Horizons probe with observations of comet Churyumov-Gerasimenko from the Euro...Despite Pluto’s demotion to dwarf planet status,people are still attached to it.Scientists combined observations of Pluto from NASA’s New Horizons probe with observations of comet Churyumov-Gerasimenko from the European Space Agency’s Rosetta probe and found that Pluto’s nitrogen abundance matched the pattern of about a billion comets,which led to the theory that Pluto is made of about a billion comets.Yet they don’t know exactly when or where these comets originated.By studying the origin and orbit of comets,the author of this paper found that the material that condensed Pluto was mainly comets and dust ejected by Neptune,and the Kuiper Belt objects were condensed by material ejected by Neptune toward the outer side of its orbit.展开更多
Background and Objective:Limbal stem cell deficiency(LSCD)is characterized by the insufficiency of limbal stem cells to maintain the corneal epithelium.Severe cases of LSCD may be treated with limbal transplantation f...Background and Objective:Limbal stem cell deficiency(LSCD)is characterized by the insufficiency of limbal stem cells to maintain the corneal epithelium.Severe cases of LSCD may be treated with limbal transplantation from healthy autologous or allogeneic limbal tissue.Multiple cell-based therapies have been studied as alternative treatments to improve success rates and minimize immunosuppressive regimens after allogeneic transplants.In this review,we describe the success rates,and complications of different cell-based therapies for LSCD.We also discuss each therapy’s relative strengths and weaknesses,their history in animal and human studies,and their effectiveness compared to traditional transplants.Methods:PubMed was searched for publications using the terms LSCD,cell-based therapy,cultivated limbal epithelial transplantation(CLET),cultivated oral mucosal epithelial transplantation(COMET),and mesenchymal stem cells from 1989 to August 2022.Inclusion criteria were English language articles.Exclusion criteria were non-English language articles.Key Content and Findings:current cell-based therapies for LSCD are CLET and non-limbal epithelial cells.Non-limbal epithelial cell methods include COMET,conjunctival epithelial autografts,and mesenchymal stem/stromal cells(MSCs).Moreover,several alternative potential sources of non-limbal cells have described,including induced pluripotent stem cells(iPSCs),human embryonic stem cells(hESCs),human dental pulp stem cells,hair follicle bulge-derived epithelial stem cells,amniotic membrane epithelial cells,and human umbilical cord lining epithelial cells.Conclusions:Cell-based therapies are a promising treatment modality for LSCD.While CLET is currently the only approved cell-based therapy and is only approved in the European Union,more novel methods have also been shown to be effective in human or animal studies thus far.Non-limbal epithelial cells such as COMET are also an alternative treatment to allogeneic transplants especially as a surface stabilizing procedure.iPSCs are currently being studied in early phase trials and have the potential to revolutionize the way LSCD is treated.Lastly,cell-based therapies for restoring the limbal niche such as mesenchymal stem cells have also shown promising results in the first human proof-of-concept study.Several potential sources of non-limbal cells are under investigation.展开更多
In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the pr...In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the protoplanet and the formation of the oldest continents. The formation of terrestrial ores occurred as a result of the release of intermediate and heavy chemical elements from the deep layers of the protoplanet and the subsequent process of adhesion to old terrestrial geological faults. The time of terrestrial and lunar ores formations corresponds to the boundary between the Tonian and Cryogenian Periods (~720 Ma). Lunar ore formation processes are different on the near and far sides. The farside of the Moon is a single piece of the protoplanetary lithosphere, so ores there could be formed mainly due to the overflow of igneous rocks over the edge of the lunar continent. On the nearside, due to the rapid cooling, ores were formed in the area of navel-string during the drip-liquid separation of the Moon from the Earth. Due to the fact that the Moon separated at the first stage, the amount of water and methane on it is limited. In periods after the Cryogenian, volcanic, lava and sedimentary rocks on Earth could be enriched with intermediate elements due to the disruption of vertical stratification during galactic storms. To analyze this, a comparison of terrestrial volcanic and lunar pseudo-volcanic activity was carried out in the work.展开更多
The construction sites of major projects are in full swing in the Tibet Autonomous Region,and the effects of the investments pouring in are only too obvious.Tourists cometo the highland in pursuit of seeing the"p...The construction sites of major projects are in full swing in the Tibet Autonomous Region,and the effects of the investments pouring in are only too obvious.Tourists cometo the highland in pursuit of seeing the"poetry of far-off wonderlands"cometo life.In the busyfarmlands and prairies,locals are casting their seeds as if they were wishing well coins bearing their hopes for bountiful agriculture and animal husbandry success in the spring as well as bumper harvests in the fall.Tibet is on the way toward the best economic advancement imaginable.展开更多
基金supported by the capital characteristic clinic project of China [Z151100004015071]National Natural Science Foundation of China [51573211]ruiyi emergency medical research fund of China [R2017013]
文摘Objective A new technique of transthoracic lung ultrasonography(TLS) has emerged and demonstrated promising results in acute heart failure diagnosis at an early stage. However, the diagnostic value of ultrasound lung comets(ULCs) for acute heart failure(AHF) performed in busy emergency department(ED) is uncertain. The present meta-analysis aimed to assess the diagnostic efficiency of ULCs in AHF. Methods We conducted a search on online journal databases to collect the data on TLS performed for diagnosing AHF published up to the end of July 2017. The sensitivity, specificity, positive likelihood ratio(PLR), negative likelihood ratio(NLR), and summary receiver operating characteristic(SROC) curve were calculated. The post-test probability of AHF was calculated by using Bayes analysis. Results We enrolled a total of 15 studies involving 3,309 patients. The value of sensitivity, specificity, PLR, NLR, DOR, area under the SROC curve, and Q* index was 85%, 91%, 8.94, 0.14, 67.24, 0.9587, and 0.9026, respectively. We detected significant heterogeneity among included studies, and therefore, all these results were analyzed under the random-effect model. We also explored possible sources of heterogeneity among the studies by using meta-regression analysis. Results suggest that the time interval between patient's admission to bedside TLS examination was closely related to TLS accuracy. Conclusion This meta-analysis demonstrated that detecting ULCs is a convenient bedside tool and has high accuracy for early AHF diagnosis in ED. TLS could be recommended to be applied for early diagnosis of AHF in ED.
文摘SUISEI is a suite of computational tools that has been developed over the past three decades and successfully applied to comets;including ComChem, a global, multi-fluid gas dynamics simulation with detailed chemical kinetics of the cometary coma;ComDust, a model of comet dust evolution and interaction with gas;and ComNuc, a 3-D simulation of gas and heat flow within the comet nucleus porous subsurface layers. The combination of these tools have resulted in an improved knowledge of chemical species in the comet’s coma and their relationship to native molecules in the nucleus ices by analyzing space- and ground-based observations and in situ measurements from spacecraft missions. A review of SUISEI is presented and applications are made to two cases: chemical recycling of HCN in comets and the physical conditions of the near-Sun object, 3200 Phaethon.
文摘Since the concept of Nongravitational Force (hereafter NF) was first proposed a century and a half ago, different models of it have been suggested and being modified. Its effect on the orbital motions of comets has been studied. Especially, some researchers have attempted to draw some inclues of the physical nature of the cometary nucleus from the NF parameters. In this paper, we try to give a concise review about the different models of NF and their effects on orbit computation. And then, we will try to detect whether there is nongravitational effect on Comet Hale-Bopp’s orbital motion using Style II NF model.
文摘Although people have studied comets for a long time and used spacecraft to detect comets in a short distance,the formation time and causes of comets are still unresolved.Therefore,according to the formation and evolution law of planets and the dynamic mechanism,the author thoroughly revealed the formation and evolution of comets:A powerful storm cyclone on Neptune,such as the Great Dark Spot,can involve a large number of clouds.These clouds are gradually cooled and compressed in the process of rapidly sinking along the spiral path,and then condense into huge water ice crystals at the bottom of the cyclone;When such a crystal falls into a deep hole filled with liquid hydrogen,it is easy to collide violently with the boulders in the hole,and instantly ignite the liquid hydrogen in the hole.Under the strong push of high-pressure gas,some fragments of the ice crystal can quickly reach a very high initial speed.Especially when the jet direction of the Great Dark Spot is consistent with the direction of Neptune’s revolution speed,such fragments can quickly reach Neptune’s escape speed of 23.56 km/s.Therefore,the fragments can break away from Neptune and enter an elliptical orbit around the sun,becoming a comet.Similarly,when the metal hydrogen at the bottom of a Great Red Spot on Jupiter explodes in a series,the fragments ejected from the Great Red Spot can reach the escape speed of Jupiter of 60 km/s,therefore,such fragments can break away from Jupiter and enter the elliptical orbit around the sun to become comets.Many of these comets can become asteroids in the asteroid belt,which is the formation principle of the asteroid belt.
文摘If you happen to gaze up in the sky at just the right time in the year 2061,you might get to see one of the most famous comets of all.It's called Halley's Comet,and people get a chance to see it every 76years when the comets orbit brings it close to the Earth.
基金the European Union’s Horizon 2020 Research and Innovation scheme under the Marie Sklodowska-Curie grant agreement No.801342(Tecniospring INDUSTRY,TECSPR-19-1-0003)the Ministry of Science and Innovation,Spain(AGL2017-88329-R and PID2020-113320RBI00)+2 种基金the Catalan Agency for Management of University and Research Grants,Regional Government of Catalonia,Spain(2017-SGR-1229)the Catalan Institution for Research and Advanced Studies(ICREA)La Maratóde TV3 Foundation(214/857-202039)。
文摘Background:The analysis of chromatin integrity has become an important determinant of sperm quality.In frozenthawed bovine sperm,neither the sequence of post-thaw injury events nor the dynamics of different types of sperm DNA breaks are well understood.The aim of the present work was to describe such sperm degradation aftermath focusing on DNA damage dynamics,and to assess if this parameter can predict pregnancy rates in cattle.Results:A total of 75 cryopreserved ejaculates from 25 Holstein bulls were evaluated at two post-thawing periods(0-2 h and 2-4 h),analyzing global and double-stranded DNA damage through alkaline and neutral Comet assays,chromatin deprotamination and decondensation,sperm motility,viability,acrosomal status,and intracellular levels of total ROS,superoxides and calcium.Insemination of 59,605 females was conducted using sperm from the same bulls,thus obtaining the non-return to estrus rates after 90 d(NRR).Results showed an increased rate of double-stranded breaks in the first period(0-2 h:1.29±1.01%/h vs.2-4 h:0.13±1.37%/h;P<0.01),whereas the rate of sperm with moderate+high single-stranded breaks was higher in the second period(0-2 h:3.52±7.77%/h vs.2-4h:21.06±11.69%/h;P<0.0001).Regarding sperm physiology,viability decrease rate was different between the two periods(0-2 h:-4.49±1.79%/h vs.2-4 h:-2.50±3.39%/h;P=0.032),but the progressive motility decrease rate was constant throughout post-thawing incubation(0-2 h:-4.70±3.42%/h vs.2-4 h:-1.89±2.97%/h;P>0.05).Finally,whereas no correlations between bull fertility and any dynamic parameter were found,there were correlations between the NRR and the basal percentage of highly-damaged sperm assessed with the alkaline Comet(Rs=-0.563,P=0.003),between NRR and basal progressive motility(Rs=0.511,P=0.009),and between NRR and sperm with high ROS at 4 h post-thaw(Rs=0.564,P=0.003).Conclusion:The statistically significant correlations found between intracellular ROS,sperm viability,sperm motility,DNA damage and chromatin deprotamination suggested a sequence of events all driven by oxidative stress,where viability and motility would be affected first and sperm chromatin would be altered at a later stage,thus suggesting that bovine sperm should be used for fertilization within 2 h post-thaw.Fertility correlations supported that the assessment of global DNA damage through the Comet assay may help predict bull fertility.
文摘Despite Pluto’s demotion to dwarf planet status,people are still attached to it.Scientists combined observations of Pluto from NASA’s New Horizons probe with observations of comet Churyumov-Gerasimenko from the European Space Agency’s Rosetta probe and found that Pluto’s nitrogen abundance matched the pattern of about a billion comets,which led to the theory that Pluto is made of about a billion comets.Yet they don’t know exactly when or where these comets originated.By studying the origin and orbit of comets,the author of this paper found that the material that condensed Pluto was mainly comets and dust ejected by Neptune,and the Kuiper Belt objects were condensed by material ejected by Neptune toward the outer side of its orbit.
基金supported by the National Eye Institute/National Institutes of Health and the Core Grant for Vision Research[R01 EY024349(ARD),UH3 EY031809(ARD),EY01792]Department of Defense Vision Research Program–Congressionally Directed Medical Research Program[VR170180]Research to Prevent Blindness Unrestricted Grant to the department and Physician-Scientist Award.
文摘Background and Objective:Limbal stem cell deficiency(LSCD)is characterized by the insufficiency of limbal stem cells to maintain the corneal epithelium.Severe cases of LSCD may be treated with limbal transplantation from healthy autologous or allogeneic limbal tissue.Multiple cell-based therapies have been studied as alternative treatments to improve success rates and minimize immunosuppressive regimens after allogeneic transplants.In this review,we describe the success rates,and complications of different cell-based therapies for LSCD.We also discuss each therapy’s relative strengths and weaknesses,their history in animal and human studies,and their effectiveness compared to traditional transplants.Methods:PubMed was searched for publications using the terms LSCD,cell-based therapy,cultivated limbal epithelial transplantation(CLET),cultivated oral mucosal epithelial transplantation(COMET),and mesenchymal stem cells from 1989 to August 2022.Inclusion criteria were English language articles.Exclusion criteria were non-English language articles.Key Content and Findings:current cell-based therapies for LSCD are CLET and non-limbal epithelial cells.Non-limbal epithelial cell methods include COMET,conjunctival epithelial autografts,and mesenchymal stem/stromal cells(MSCs).Moreover,several alternative potential sources of non-limbal cells have described,including induced pluripotent stem cells(iPSCs),human embryonic stem cells(hESCs),human dental pulp stem cells,hair follicle bulge-derived epithelial stem cells,amniotic membrane epithelial cells,and human umbilical cord lining epithelial cells.Conclusions:Cell-based therapies are a promising treatment modality for LSCD.While CLET is currently the only approved cell-based therapy and is only approved in the European Union,more novel methods have also been shown to be effective in human or animal studies thus far.Non-limbal epithelial cells such as COMET are also an alternative treatment to allogeneic transplants especially as a surface stabilizing procedure.iPSCs are currently being studied in early phase trials and have the potential to revolutionize the way LSCD is treated.Lastly,cell-based therapies for restoring the limbal niche such as mesenchymal stem cells have also shown promising results in the first human proof-of-concept study.Several potential sources of non-limbal cells are under investigation.
文摘In this study, the theory of ore formation on the Earth and the Moon was developed. It is shown that ore deposits on the Earth and the Moon were mainly formed simultaneously with the separation of the Moon from the protoplanet and the formation of the oldest continents. The formation of terrestrial ores occurred as a result of the release of intermediate and heavy chemical elements from the deep layers of the protoplanet and the subsequent process of adhesion to old terrestrial geological faults. The time of terrestrial and lunar ores formations corresponds to the boundary between the Tonian and Cryogenian Periods (~720 Ma). Lunar ore formation processes are different on the near and far sides. The farside of the Moon is a single piece of the protoplanetary lithosphere, so ores there could be formed mainly due to the overflow of igneous rocks over the edge of the lunar continent. On the nearside, due to the rapid cooling, ores were formed in the area of navel-string during the drip-liquid separation of the Moon from the Earth. Due to the fact that the Moon separated at the first stage, the amount of water and methane on it is limited. In periods after the Cryogenian, volcanic, lava and sedimentary rocks on Earth could be enriched with intermediate elements due to the disruption of vertical stratification during galactic storms. To analyze this, a comparison of terrestrial volcanic and lunar pseudo-volcanic activity was carried out in the work.
文摘The construction sites of major projects are in full swing in the Tibet Autonomous Region,and the effects of the investments pouring in are only too obvious.Tourists cometo the highland in pursuit of seeing the"poetry of far-off wonderlands"cometo life.In the busyfarmlands and prairies,locals are casting their seeds as if they were wishing well coins bearing their hopes for bountiful agriculture and animal husbandry success in the spring as well as bumper harvests in the fall.Tibet is on the way toward the best economic advancement imaginable.
