Ultrafast optical spectroscopy of a single crystal of a Dirac semimetal Cd_3As_（2 ）is carried out.An acoustic phonon（AP）mode with central frequency f=0.037 THz（i.e.,1.23 cm^（-1）or 0.153 meV）is unambiguously ge...Ultrafast optical spectroscopy of a single crystal of a Dirac semimetal Cd_3As_（2 ）is carried out.An acoustic phonon（AP）mode with central frequency f=0.037 THz（i.e.,1.23 cm^（-1）or 0.153 meV）is unambiguously generated and detected,which we attribute to laser-induced thermal strain.An AP chirping（i.e.,variation of the phonon frequency）is clearly detected,which is ascribed to heat capacity variation with time.By comparing our experimental results and the theoretical model,we obtain a chirping time constant,which is 31.2 ps at 6 K and 19.8 ps at 300 K,respectively.Significantly,we identify an asymmetry in the AP frequency domain peak and find that it is caused by the chirping,instead of a Fano resonance.Moreover,we experimentally demonstrate that the central frequency of AP is extremely stable with varying laser fluence,as well as temperature,which endows Cd_3As_2application potentials in thermoelectric devices.展开更多
We are interested in investigating whether cancer therapy may alter the mitochondrial redox state in cancer cells to inhibit their growth and survival.The redox state can be imaged by the redox scanner that collects t...We are interested in investigating whether cancer therapy may alter the mitochondrial redox state in cancer cells to inhibit their growth and survival.The redox state can be imaged by the redox scanner that collects the fuorescence signals from both the oxidized-fAavoproteins(Fp)and the reduced form of nicotinamide adenine dinucleotide(NADH)in snap frozen tissues and has been previously employed to study tumor aggressiveness and treatment responses.Here,with the redox scanner we investigated the effects of chemotherapy on mouse xenografts of a human diffuse large B.cell lymphoma cell line(DLCL2).The mice were treated with CHOP therapy,i.e,cyclophosphamide(C)+hydroxydoxorubicin(H)+Oncovin(O)+prednisone(P)with CHO administration on day 1 and prednisone administration on days 1-5.The Fp content of the treated group was significantly decreased(p=0.033)on day 5,and the mitochondrial redox state of the treated group was slightly more reduced than that of the control group(p=0.048).The decrease of the Fp heterogeneity(measured by the mean st andard deviation)had a border-line statistical significance(p=0.071).The result suggests that the mitochondrial metabolism of lymphoma cells was slightly suppressed and the lymphomas became less aggressive after the CHOP therapy.展开更多
1 Results The oxidation of alcohols into the corresponding carbonyl compound is one of the most important functional group transformation in organic synthesis[1]. Traditionally,such transformations have been performed...1 Results The oxidation of alcohols into the corresponding carbonyl compound is one of the most important functional group transformation in organic synthesis[1]. Traditionally,such transformations have been performed with stoichiometric inorganic oxidant or other high valent metal oxidant[2]. Despite a variety of systems for the catalytic oxidation of alcohols have been developed,there is ongoing interest in the search for new efficient and environmental friendly oxidation system.To the best of our kno...展开更多
I close my eyes. The children with whom I stayed with in Lhasa appear before me. In the pink world they smile. It is a strange feeling. I have been to Tibet twice. I remember how the Lhasa children would walk on the s...I close my eyes. The children with whom I stayed with in Lhasa appear before me. In the pink world they smile. It is a strange feeling. I have been to Tibet twice. I remember how the Lhasa children would walk on the streets in Lhasa: when they spotted a man and a woman holding hands, they would sing, "You Are Late", a popular song of that time. "I had her in my heart a long time ago./Oh! She arrived before you." When the young couple turned around, the children would run away. Then they searched for another couple. What I most remember about Tibet展开更多
I am 76 years old this year. I was one of the women cadres who participated in the War of Resistance Against Japan in 1937. I was born in a village located in Shenxian County, Hengshui Area, Hebei Province. Mine was a...I am 76 years old this year. I was one of the women cadres who participated in the War of Resistance Against Japan in 1937. I was born in a village located in Shenxian County, Hengshui Area, Hebei Province. Mine was a big family. Two of my uncles were teachers of an old-style private school. They enjoyed a decent social status and were respected by the local people. My father used to work in the county seat; later on, he also returned to his native village. Though he worked as a farmer, he too had had some schooling. At that time, Dr. Sun Yat-sen had展开更多
基金Supported by the National Key Research and Development Program of China under Grant Nos 2017YFA0303603,2016YFA0300303,2017YFA0302901 and 2016YFA0300604the National Natural Science Foundation of China under Grant Nos11774408,11574383 and 11774399+1 种基金the External Cooperation Program of Chinese Academy of Sciences under Grant No GJHZ1826the Interdisciplinary Innovation Team of Chinese Academy of Sciences
文摘Ultrafast optical spectroscopy of a single crystal of a Dirac semimetal Cd_3As_（2 ）is carried out.An acoustic phonon（AP）mode with central frequency f=0.037 THz（i.e.,1.23 cm^（-1）or 0.153 meV）is unambiguously generated and detected,which we attribute to laser-induced thermal strain.An AP chirping（i.e.,variation of the phonon frequency）is clearly detected,which is ascribed to heat capacity variation with time.By comparing our experimental results and the theoretical model,we obtain a chirping time constant,which is 31.2 ps at 6 K and 19.8 ps at 300 K,respectively.Significantly,we identify an asymmetry in the AP frequency domain peak and find that it is caused by the chirping,instead of a Fano resonance.Moreover,we experimentally demonstrate that the central frequency of AP is extremely stable with varying laser fluence,as well as temperature,which endows Cd_3As_2application potentials in thermoelectric devices.
基金The grant support to this work incude the Center of Magnetic Resonance and Optical Imaging(CMROI)-an NIH-supported research resource P41RR02305(R.Reddy)the Small A nimal Imaging Resources Program(SAIR)2U24-CA083105(J.D.Glickson and L.Chodosh)+1 种基金2R01-CA101700(J.D.Glickson)NIH K99/R00-CA 126187(R.Choe)。
文摘We are interested in investigating whether cancer therapy may alter the mitochondrial redox state in cancer cells to inhibit their growth and survival.The redox state can be imaged by the redox scanner that collects the fuorescence signals from both the oxidized-fAavoproteins(Fp)and the reduced form of nicotinamide adenine dinucleotide(NADH)in snap frozen tissues and has been previously employed to study tumor aggressiveness and treatment responses.Here,with the redox scanner we investigated the effects of chemotherapy on mouse xenografts of a human diffuse large B.cell lymphoma cell line(DLCL2).The mice were treated with CHOP therapy,i.e,cyclophosphamide(C)+hydroxydoxorubicin(H)+Oncovin(O)+prednisone(P)with CHO administration on day 1 and prednisone administration on days 1-5.The Fp content of the treated group was significantly decreased(p=0.033)on day 5,and the mitochondrial redox state of the treated group was slightly more reduced than that of the control group(p=0.048).The decrease of the Fp heterogeneity(measured by the mean st andard deviation)had a border-line statistical significance(p=0.071).The result suggests that the mitochondrial metabolism of lymphoma cells was slightly suppressed and the lymphomas became less aggressive after the CHOP therapy.
文摘1 Results The oxidation of alcohols into the corresponding carbonyl compound is one of the most important functional group transformation in organic synthesis[1]. Traditionally,such transformations have been performed with stoichiometric inorganic oxidant or other high valent metal oxidant[2]. Despite a variety of systems for the catalytic oxidation of alcohols have been developed,there is ongoing interest in the search for new efficient and environmental friendly oxidation system.To the best of our kno...
文摘I close my eyes. The children with whom I stayed with in Lhasa appear before me. In the pink world they smile. It is a strange feeling. I have been to Tibet twice. I remember how the Lhasa children would walk on the streets in Lhasa: when they spotted a man and a woman holding hands, they would sing, "You Are Late", a popular song of that time. "I had her in my heart a long time ago./Oh! She arrived before you." When the young couple turned around, the children would run away. Then they searched for another couple. What I most remember about Tibet
文摘I am 76 years old this year. I was one of the women cadres who participated in the War of Resistance Against Japan in 1937. I was born in a village located in Shenxian County, Hengshui Area, Hebei Province. Mine was a big family. Two of my uncles were teachers of an old-style private school. They enjoyed a decent social status and were respected by the local people. My father used to work in the county seat; later on, he also returned to his native village. Though he worked as a farmer, he too had had some schooling. At that time, Dr. Sun Yat-sen had
