We present a fully stabilized Yb-fiber frequency comb locked to a microwave standard and an optical reference separately. The carrier-envelope offset frequency is generated by a standard f–2f interferometer with 40 d...We present a fully stabilized Yb-fiber frequency comb locked to a microwave standard and an optical reference separately. The carrier-envelope offset frequency is generated by a standard f–2f interferometer with 40 dB signal-tonoise ratio. The offset frequency and the repetition rate are stabilized simultaneously to the radio frequency reference for more than 30 hours, and the fractional Allan deviation of the comb is the same as the microwave standard of 10^(-12) at 1 s.Alternatively, the comb is locked to an ultra-stable optical reference at 972 nm using an intracavity electro-optic modulator,exhibiting a residual integrated phase noise of 458 mrad(1 Hz–10 MHz) and an in-loop tracking stability of 1.77× 10^(-18) at 1 s, which is significantly raised by six orders comparing to the case locked to the microwave frequency standard.展开更多
A monolithic O-f scheme-based femtosecond optical frequency comb directly driven by a high-power Ti:sapphire laser oscillator is demonstrated.The spectrum covering from 650 nm to 950 nm is generated from the Ti:sapphi...A monolithic O-f scheme-based femtosecond optical frequency comb directly driven by a high-power Ti:sapphire laser oscillator is demonstrated.The spectrum covering from 650 nm to 950 nm is generated from the Ti:sapphire oscillator with a repetition rate of 170 MHz.The average output power up to 630 mW is delivered under the pump power of 4.5 W.A 44-dB signal-to-noise ratio(SNR)of the carrier-envelope phase offset(CEO)beat note is achieved under the resolution of 100 kHz and is long-term stabilized to a reference source at 20 MHz.The integrated phase noise(IPN)in the range from 1 Hz to 1 MHz is calculated to be 138 mrad,corresponding to the timing jitter of 63 as at the central wavelength of 790 nm.展开更多
BACKGROUND Angiosarcoma is a rare disease with a poor prognosis.Its occurrence in the small intestine is low,and gastrointestinal bleeding caused by small intestinal angiosarcoma is unusual.CASE SUMMARY Here,we report...BACKGROUND Angiosarcoma is a rare disease with a poor prognosis.Its occurrence in the small intestine is low,and gastrointestinal bleeding caused by small intestinal angiosarcoma is unusual.CASE SUMMARY Here,we report the case of a 57-year-old man who presented with hematochezia for 1 mo.The patient had a medical history of chronic viral hepatitis B for 15 years.The causes of gastrointestinal bleeding were initially diagnosed as esophagogastric variceal bleeding or portal hypertensive gastropathy before endoscopy.However,after a complicated diagnostic and therapeutic process,including gastroendoscopy,colonoscopy,contrast-enhanced computed tomographic(CT),positron emission computed tomography/CT,capsule endoscopy,and pathological and immunohistochemical examinations,small intestinal angiosarcoma was diagnosed.Arrest of bleeding was achieved after surgical treatment.Furthermore,the patient had lung cancer with bone and adrenal metastases.At the follow-up 10 mo after the operation,the patient was alive.CONCLUSION Gastroenterologists should maintain strong vigilance to small intestinal angiosarcoma,which is necessary for the early identification of this infrequent but fatal disease.展开更多
Chronic pain is a common clinical condition that is frequently linked to negative emotions such as anxiety and depression.Electroacupuncture(EA) has been shown to have beneficial therapeutic effects in analgesia and t...Chronic pain is a common clinical condition that is frequently linked to negative emotions such as anxiety and depression.Electroacupuncture(EA) has been shown to have beneficial therapeutic effects in analgesia and the reduction of pain-induced negative emotions,and promising results have been obtained in the study of its neural circuit mechanism.Optogenetics,chemogenetics,neurocircuit tracing,functional magnetic resonance imaging(fMRI),and conditional gene knockdown experiments have shown that EA activates parvalbumin(PV) interneurons in the anterior cingulate cortex(ACC),inhibits Protein kinase Mzeta-glutamate receptor(PKMzeta-GluR1) signaling pathway in ACC,and upregulates the expression of the neuropeptide S/neuropeptide S receptor(NPS/NPSR) system in ACC to alleviate pain and pain-induced anxiety.EA activates endogenous cannabinoid receptors 1(CB1Rs),inhibits y-aminobutyric acid(^(GABA))-ergic neurons and activates glutamatergic neurons in the ventrolateral periaqueductal gray(vlPAG) to exert an analgesic effect,while EA exerts an anxiolytic effect by downregulating CB1R in ^(GABA)ergic neurons in the ventral hippocampus(vHPC).EA relieves only pain-induced anxiety but not pain through inhibiting the rostral anterior cingulate cortex(rACC)Glu-thalamus circuit.By inhibiting the medial prefrontal cortex(mPFC)Glu-vlPAC^(GABA)circuit,EA relieves only pain but not pain-induced anxiety.EA activated dopamine receptor D1(DRD1) or inhibited dopamine receptor D2(DRD2) in the basolateral amygdala(BLA) to alleviate anxiety-like behaviors.Taken together,these findings would offer a novel theoretical framework for a thorough investigation of theoretical studies and clinical promotion of EA analgesic mechanisms.展开更多
基金Project supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA1502040404 and XDB21010400)the National Natural Science Foundation of China(Grant Nos.91850209 and 11774234)。
文摘We present a fully stabilized Yb-fiber frequency comb locked to a microwave standard and an optical reference separately. The carrier-envelope offset frequency is generated by a standard f–2f interferometer with 40 dB signal-tonoise ratio. The offset frequency and the repetition rate are stabilized simultaneously to the radio frequency reference for more than 30 hours, and the fractional Allan deviation of the comb is the same as the microwave standard of 10^(-12) at 1 s.Alternatively, the comb is locked to an ultra-stable optical reference at 972 nm using an intracavity electro-optic modulator,exhibiting a residual integrated phase noise of 458 mrad(1 Hz–10 MHz) and an in-loop tracking stability of 1.77× 10^(-18) at 1 s, which is significantly raised by six orders comparing to the case locked to the microwave frequency standard.
基金National Key R&D Program of China(Grant No.2017YFC0110301)National Natural Science Foundation of China(Grant Nos.91950113,61575219,61210017,11774234,11674386,11434016,and 91850209)+1 种基金Strategic Priority Research Program of the CAS(Grant No.XDB23030203)Youth Innovation Promotion Association of the CAS(Grant No.2018007)。
文摘A monolithic O-f scheme-based femtosecond optical frequency comb directly driven by a high-power Ti:sapphire laser oscillator is demonstrated.The spectrum covering from 650 nm to 950 nm is generated from the Ti:sapphire oscillator with a repetition rate of 170 MHz.The average output power up to 630 mW is delivered under the pump power of 4.5 W.A 44-dB signal-to-noise ratio(SNR)of the carrier-envelope phase offset(CEO)beat note is achieved under the resolution of 100 kHz and is long-term stabilized to a reference source at 20 MHz.The integrated phase noise(IPN)in the range from 1 Hz to 1 MHz is calculated to be 138 mrad,corresponding to the timing jitter of 63 as at the central wavelength of 790 nm.
基金Science and Technology Program of Tianjin,No.19PTZWHZ00090 and No.15ZXJZSY00020National Natural Science Foundation of China,No.81503019 and No.81200261Natural Science Foundation of Tianjin City,No.18JCZDJC45200.
文摘BACKGROUND Angiosarcoma is a rare disease with a poor prognosis.Its occurrence in the small intestine is low,and gastrointestinal bleeding caused by small intestinal angiosarcoma is unusual.CASE SUMMARY Here,we report the case of a 57-year-old man who presented with hematochezia for 1 mo.The patient had a medical history of chronic viral hepatitis B for 15 years.The causes of gastrointestinal bleeding were initially diagnosed as esophagogastric variceal bleeding or portal hypertensive gastropathy before endoscopy.However,after a complicated diagnostic and therapeutic process,including gastroendoscopy,colonoscopy,contrast-enhanced computed tomographic(CT),positron emission computed tomography/CT,capsule endoscopy,and pathological and immunohistochemical examinations,small intestinal angiosarcoma was diagnosed.Arrest of bleeding was achieved after surgical treatment.Furthermore,the patient had lung cancer with bone and adrenal metastases.At the follow-up 10 mo after the operation,the patient was alive.CONCLUSION Gastroenterologists should maintain strong vigilance to small intestinal angiosarcoma,which is necessary for the early identification of this infrequent but fatal disease.
基金Sponsored by National Natural Science Foundation of China:No.81973949。
文摘Chronic pain is a common clinical condition that is frequently linked to negative emotions such as anxiety and depression.Electroacupuncture(EA) has been shown to have beneficial therapeutic effects in analgesia and the reduction of pain-induced negative emotions,and promising results have been obtained in the study of its neural circuit mechanism.Optogenetics,chemogenetics,neurocircuit tracing,functional magnetic resonance imaging(fMRI),and conditional gene knockdown experiments have shown that EA activates parvalbumin(PV) interneurons in the anterior cingulate cortex(ACC),inhibits Protein kinase Mzeta-glutamate receptor(PKMzeta-GluR1) signaling pathway in ACC,and upregulates the expression of the neuropeptide S/neuropeptide S receptor(NPS/NPSR) system in ACC to alleviate pain and pain-induced anxiety.EA activates endogenous cannabinoid receptors 1(CB1Rs),inhibits y-aminobutyric acid(^(GABA))-ergic neurons and activates glutamatergic neurons in the ventrolateral periaqueductal gray(vlPAG) to exert an analgesic effect,while EA exerts an anxiolytic effect by downregulating CB1R in ^(GABA)ergic neurons in the ventral hippocampus(vHPC).EA relieves only pain-induced anxiety but not pain through inhibiting the rostral anterior cingulate cortex(rACC)Glu-thalamus circuit.By inhibiting the medial prefrontal cortex(mPFC)Glu-vlPAC^(GABA)circuit,EA relieves only pain but not pain-induced anxiety.EA activated dopamine receptor D1(DRD1) or inhibited dopamine receptor D2(DRD2) in the basolateral amygdala(BLA) to alleviate anxiety-like behaviors.Taken together,these findings would offer a novel theoretical framework for a thorough investigation of theoretical studies and clinical promotion of EA analgesic mechanisms.