A cold preamplifier based on superconducting quantum interference devices(SQUIDs)is currently the preferred readout technology for the low-noise transition edge sensor(TES).In this work,we have designed and fabricated...A cold preamplifier based on superconducting quantum interference devices(SQUIDs)is currently the preferred readout technology for the low-noise transition edge sensor(TES).In this work,we have designed and fabricated a series SQUID array(SSA)amplifier for the TES detector readout circuit.In this SSA amplifier,each SQUID cell is composed of a first-order gradiometer formed using two equally large square washers,and an on-chip low pass filter(LPF)as a radiofrequency(RF)choke has been developed to reduce the Josephson oscillation interference between individual SQUID cells.In addition,a highly symmetric layout has been designed carefully to provide a fully consistent embedded electromagnetic environment and achieve coherent flux operation.The measured results show smooth V-Φcharacteristics and a swing voltage that increases linearly with increasing SQUID cell number N.A white flux noise level as low as 0.28μφ;/Hz;is achieved at 0.1 K,corresponding to a low current noise level of 7 pA/Hz;.We analyze the measured noise contribution at mK-scale temperatures and find that the dominant noise derives from a combination of the SSA intrinsic noise and the equivalent current noise of the room temperature electronics.展开更多
Josephson parametric amplifiers (JPAs) with nearly quantum-limited noise performance have become indispensable devices for the measurements of superconducting quantum information. We have developed an all-Nb lumped-el...Josephson parametric amplifiers (JPAs) with nearly quantum-limited noise performance have become indispensable devices for the measurements of superconducting quantum information. We have developed an all-Nb lumped-element flux-driven JPA operating in the three-wave mixing mode. Our Nb-based JPA comprises Nb/Al-AlOx/Nb Josephson junctions, a parallel-plate capacitor with SiO2 dielectric sandwiched between two Nb layers, a bottom coplanar waveguides layer, and a top Nb wiring layer. We experimentally demonstrate a 20 dB gain over a 190 MHz bandwidth, a mean 1 dB compression of -123 dBm, and near quantum-limited noise performance. This fabrication process can be further used to design impedance transformed parametric amplifiers for multiple-qubit readout.展开更多
Single-flux-quantum(SFQ)circuits have great potential in building cryogenic quantum-classical interfaces for scaling up superconducting quantum processors.SFQ-based quantum gates have been designed and realized.Howeve...Single-flux-quantum(SFQ)circuits have great potential in building cryogenic quantum-classical interfaces for scaling up superconducting quantum processors.SFQ-based quantum gates have been designed and realized.However,current control schemes are difficult to tune the driving strength to qubits,which restricts the gate length and usually induces leakage to unwanted levels.In this study,we design the scheme and corresponding pulse generator circuit to continuously adjust the driving strength by coupling SFQ pulses with variable intervals.This scheme not only provides a way to adjust the SFQ-based gate length,but also proposes the possibility to tune the driving strength envelope.Simulations show that our scheme can suppress leakage to unwanted levels and reduce the error of SFQ-based Clifford gates by more than an order of magnitude.展开更多
Background: Infectious keratitis after refractive surgery is uncommon, and mycobacterium abscess has never been observed in corneal infections in China. Purpose: To propose an unusual presentation of two cases about M...Background: Infectious keratitis after refractive surgery is uncommon, and mycobacterium abscess has never been observed in corneal infections in China. Purpose: To propose an unusual presentation of two cases about Mycobacterium abscess infection after laser in situ keratomileusis (LASIK). Participants: Both cases 1 and 2 were females who exhibited a corneal ulceration after LASIK in the same hospital. Methods: The first patient in the study was a 28-year-old woman who underwent Epi-LASIK surgery in both eyes. She developed an infectious corneal ulcer in one eye after 50 days post-surgery. She was referred to our out-patient clinic 3 months post-surgery with corneal perforation, and was treated with a therapeutic penetrating keratoplasty. The second patient was a 27-year-old woman who developed infectious keratitis in one eye after 2 months after bilateral LASIK and was referred to us 3 months later. Results: Cultures in both the cases were identified as a Mycobacterium abscess, and case 1 was treated with penetrating keratoplasty eventually, while case 2 recovered after sensitive treatment. Conclusions: Infectious keratitis after refractive surgery is uncommon, and Mycobacterium abscess has never been observed in corneal infections. An accurate diagnosis and identification of the causative agent is very important.展开更多
The bromodomain and extraterminal(BET)family member BRD4 is pivotal in the pathogenesis of cardiac hypertrophy.BRD4 induces hypertrophic gene expression by binding to the acetylated chromatin,facilitating the phosphor...The bromodomain and extraterminal(BET)family member BRD4 is pivotal in the pathogenesis of cardiac hypertrophy.BRD4 induces hypertrophic gene expression by binding to the acetylated chromatin,facilitating the phosphorylation of RNA polymerases II(Pol II)and leading to transcription elongation.The present study identified a novel post-translational modification of BRD4:poly(ADPribosyl)ation(PARylation),that was mediated by poly(ADP-ribose)polymerase-1(PARP1)in cardiac hypertrophy.BRD4 silencing or BET inhibitors JQ1 and MS417 prevented cardiac hypertrophic responses induced by isoproterenol(ISO),whereas overexpression of BRD4 promoted cardiac hypertrophy,confirming the critical role of BRD4 in pathological cardiac hypertrophy.PARP1 was activated in ISOinduced cardiac hypertrophy and facilitated the development of cardiac hypertrophy.BRD4 was involved in the prohypertrophic effect of PARP1,as implied by the observations that BRD4 inhibition or silencing reversed PARP1-induced hypertrophic responses,and that BRD4 overexpression suppressed the antihypertrophic effect of PARP1 inhibitors.Interactions of BRD4 and PARP1 were observed by coimmunoprecipitation and immunofluorescence.PARylation of BRD4 induced by PARP1 was investigated by PARylation assays.In response to hypertrophic stimuli like ISO,PARylation level of BRD4 was elevated,along with enhanced interactions between BRD4 and PARP1.By investigating the PARylation of truncation mutants of BRD4,the C-terminal domain(CTD)was identified as the PARylation modification sites of BRD4.PARylation of BRD4 facilitated its binding to the transcription start sites(TSS)of hypertrophic genes,resulting in enhanced phosphorylation of RNA Pol II and transcription activation of hypertrophic genes.The present findings suggest that strategies targeting inhibition of PARP1-BRD4 might have therapeutic potential for pathological cardiac hypertrophy.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2017YFA0304003)。
文摘A cold preamplifier based on superconducting quantum interference devices(SQUIDs)is currently the preferred readout technology for the low-noise transition edge sensor(TES).In this work,we have designed and fabricated a series SQUID array(SSA)amplifier for the TES detector readout circuit.In this SSA amplifier,each SQUID cell is composed of a first-order gradiometer formed using two equally large square washers,and an on-chip low pass filter(LPF)as a radiofrequency(RF)choke has been developed to reduce the Josephson oscillation interference between individual SQUID cells.In addition,a highly symmetric layout has been designed carefully to provide a fully consistent embedded electromagnetic environment and achieve coherent flux operation.The measured results show smooth V-Φcharacteristics and a swing voltage that increases linearly with increasing SQUID cell number N.A white flux noise level as low as 0.28μφ;/Hz;is achieved at 0.1 K,corresponding to a low current noise level of 7 pA/Hz;.We analyze the measured noise contribution at mK-scale temperatures and find that the dominant noise derives from a combination of the SSA intrinsic noise and the equivalent current noise of the room temperature electronics.
基金Project supported by the National Natural Science Foundation of China(Grant No.92065116)Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA18000000)the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2020B0303030002).
文摘Josephson parametric amplifiers (JPAs) with nearly quantum-limited noise performance have become indispensable devices for the measurements of superconducting quantum information. We have developed an all-Nb lumped-element flux-driven JPA operating in the three-wave mixing mode. Our Nb-based JPA comprises Nb/Al-AlOx/Nb Josephson junctions, a parallel-plate capacitor with SiO2 dielectric sandwiched between two Nb layers, a bottom coplanar waveguides layer, and a top Nb wiring layer. We experimentally demonstrate a 20 dB gain over a 190 MHz bandwidth, a mean 1 dB compression of -123 dBm, and near quantum-limited noise performance. This fabrication process can be further used to design impedance transformed parametric amplifiers for multiple-qubit readout.
基金Project supported in part by the National Natural Science Foundation of China (Grant No.92065116)the Key-Area Research and Development Program of Guangdong Province,China (Grant No.2020B0303030002)+1 种基金the Shanghai Technology Innovation Action Plan Integrated Circuit Technology Support Program (Grant No.22DZ1100200)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA18000000)。
文摘Single-flux-quantum(SFQ)circuits have great potential in building cryogenic quantum-classical interfaces for scaling up superconducting quantum processors.SFQ-based quantum gates have been designed and realized.However,current control schemes are difficult to tune the driving strength to qubits,which restricts the gate length and usually induces leakage to unwanted levels.In this study,we design the scheme and corresponding pulse generator circuit to continuously adjust the driving strength by coupling SFQ pulses with variable intervals.This scheme not only provides a way to adjust the SFQ-based gate length,but also proposes the possibility to tune the driving strength envelope.Simulations show that our scheme can suppress leakage to unwanted levels and reduce the error of SFQ-based Clifford gates by more than an order of magnitude.
文摘Background: Infectious keratitis after refractive surgery is uncommon, and mycobacterium abscess has never been observed in corneal infections in China. Purpose: To propose an unusual presentation of two cases about Mycobacterium abscess infection after laser in situ keratomileusis (LASIK). Participants: Both cases 1 and 2 were females who exhibited a corneal ulceration after LASIK in the same hospital. Methods: The first patient in the study was a 28-year-old woman who underwent Epi-LASIK surgery in both eyes. She developed an infectious corneal ulcer in one eye after 50 days post-surgery. She was referred to our out-patient clinic 3 months post-surgery with corneal perforation, and was treated with a therapeutic penetrating keratoplasty. The second patient was a 27-year-old woman who developed infectious keratitis in one eye after 2 months after bilateral LASIK and was referred to us 3 months later. Results: Cultures in both the cases were identified as a Mycobacterium abscess, and case 1 was treated with penetrating keratoplasty eventually, while case 2 recovered after sensitive treatment. Conclusions: Infectious keratitis after refractive surgery is uncommon, and Mycobacterium abscess has never been observed in corneal infections. An accurate diagnosis and identification of the causative agent is very important.
基金supported by grants from the National Natural Science Foundation of China(81872860,81673433,and 81973318)Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01Y093,China)+6 种基金National Major Special Projects for the Creation and Manufacture of New Drugs(2019ZX09301104,China)Special Program for Applied Science and Technology of Guangdong Province(2015B020232009,China)National Engineering and Technology Research Center for New drug Druggability Evaluation(Seed Program of Guangdong Province,2017B090903004,China)Guangdong Basic and Applied Basic Research Foundation(2019A1515011256,China)Guangzhou Science and Technology Program Project(201604020121 and 201804010227,China)Yang Fan Project of Guangdong Province(Grant No.2014YT02S044,China)Guangdong Provincial Key Laboratory of Construction Foundation(No.2017B030314030,China)。
文摘The bromodomain and extraterminal(BET)family member BRD4 is pivotal in the pathogenesis of cardiac hypertrophy.BRD4 induces hypertrophic gene expression by binding to the acetylated chromatin,facilitating the phosphorylation of RNA polymerases II(Pol II)and leading to transcription elongation.The present study identified a novel post-translational modification of BRD4:poly(ADPribosyl)ation(PARylation),that was mediated by poly(ADP-ribose)polymerase-1(PARP1)in cardiac hypertrophy.BRD4 silencing or BET inhibitors JQ1 and MS417 prevented cardiac hypertrophic responses induced by isoproterenol(ISO),whereas overexpression of BRD4 promoted cardiac hypertrophy,confirming the critical role of BRD4 in pathological cardiac hypertrophy.PARP1 was activated in ISOinduced cardiac hypertrophy and facilitated the development of cardiac hypertrophy.BRD4 was involved in the prohypertrophic effect of PARP1,as implied by the observations that BRD4 inhibition or silencing reversed PARP1-induced hypertrophic responses,and that BRD4 overexpression suppressed the antihypertrophic effect of PARP1 inhibitors.Interactions of BRD4 and PARP1 were observed by coimmunoprecipitation and immunofluorescence.PARylation of BRD4 induced by PARP1 was investigated by PARylation assays.In response to hypertrophic stimuli like ISO,PARylation level of BRD4 was elevated,along with enhanced interactions between BRD4 and PARP1.By investigating the PARylation of truncation mutants of BRD4,the C-terminal domain(CTD)was identified as the PARylation modification sites of BRD4.PARylation of BRD4 facilitated its binding to the transcription start sites(TSS)of hypertrophic genes,resulting in enhanced phosphorylation of RNA Pol II and transcription activation of hypertrophic genes.The present findings suggest that strategies targeting inhibition of PARP1-BRD4 might have therapeutic potential for pathological cardiac hypertrophy.
