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1.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi ; 56(12): 1256-1262, 2021 Dec 07.
Artigo em Chinês | MEDLINE | ID: mdl-34963212

RESUMO

Objective: To investigate theaccuracy of artificial intelligence sleep staging model in patients with habitual snoring and obstructive sleep apnea hypopnea syndrome (OSAHS) based on single-channel EEG collected from different locations of the head. Methods: The clinical data of 114 adults with habitual snoring and OSAHS who visited to the Sleep Medicine Center of Beijing Tongren Hospital from September 2020 to March of 2021 were analyzed retrospectively, including 93 males and 21 females, aging from 20 to 64 years old. Eighty-five adults with OSAHS and 29 subjects with habitual snoring were included. Sleep staging analysis was performed on the single lead EEG signals of different locations (FP2-M1, C4-M1, F3-M2, ROG-M1, O1-M2) using the deep learning segmentation model trained by previous data. Manual scoring results were used as the gold standard to analyze the consistency rate of results and the influence of different categories of disease. Results: EEG data in 124 747 30-second epochs were taken as the testing dataset. The model accuracy of distinguishing wake/sleep was 92.3%,92.6%,93.5%,89.2% and 83.0% respectively,based on EEG channel Fp2-M1, C4-M1, F3-M2, REOG-M1 or O1-M2. The mode accuracy of distinguishing wake/REM/NREM and wake/REM/N1-2/SWS , was 84.7% and 80.1% respectively based on channel Fp2-M1, which located in forehead skin. The AHI calculated based on total sleep time derived from the model and gold standard were 13.6[4.30,42.5] and 14.2[4.8,42.7], respectively (Z=-2.477, P=0.013), and the kappa coefficient was 0.977. Conclusions: The autonomic sleep staging via a deep neural network model based on forehead single-channel EEG (Fp2-M1) has a good consistency in the identification sleep stage in a population with habitual snoring and OSAHS with different categories. The AHI calculated based on this model has high consistency with manual scoring.


Assuntos
Inteligência Artificial , Fases do Sono , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Redes Neurais de Computação , Estudos Retrospectivos , Sono , Adulto Jovem
2.
Phys Rev Lett ; 123(23): 233602, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31868475

RESUMO

Virtual photons can mediate interaction between atoms, resulting in an energy shift known as a collective Lamb shift. Observing the collective Lamb shift is challenging, since it can be obscured by radiative decay and direct atom-atom interactions. Here, we place two superconducting qubits in a transmission line terminated by a mirror, which suppresses decay. We measure a collective Lamb shift reaching 0.8% of the qubit transition frequency and twice the transition linewidth. We also show that the qubits can interact via the transmission line even if one of them does not decay into it.

3.
Nat Commun ; 2: 377, 2011 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-21730958

RESUMO

A quantum simulator is a well-controlled quantum system that can follow the evolution of a prescribed model whose behaviour may be difficult to determine. A good example is the simulation of a set of interacting spins, where phase transitions between various spin orders can underlie poorly understood concepts such as spin liquids. Here we simulate the emergence of magnetism by implementing a fully connected non-uniform ferromagnetic quantum Ising model using up to 9 trapped (171)Yb(+) ions. By increasing the Ising coupling strengths compared with the transverse field, the crossover from paramagnetism to ferromagnetic order sharpens as the system is scaled up, prefacing the expected quantum phase transition in the thermodynamic limit. We measure scalable order parameters appropriate for large systems, such as various moments of the magnetization. As the results are theoretically tractable, this work provides a critical benchmark for the simulation of intractable arbitrary fully connected Ising models in larger systems.


Assuntos
Modelos Teóricos , Transição de Fase , Teoria Quântica , Simulação por Computador , Fluorescência , Isótopos/química , Magnetismo , Método de Monte Carlo , Termodinâmica , Itérbio/química
4.
Phys Rev Lett ; 106(23): 230402, 2011 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-21770485

RESUMO

Sharp quantum phase transitions typically require a large system with many particles. Here we show that, for a frustrated fully connected Ising spin network represented by trapped atomic ions, the competition between different spin orders leads to rich phase transitions whose sharpness scales exponentially with the number of spins. This unusual finite-size scaling behavior opens up the possibility of observing sharp quantum phase transitions in a system of just a few trapped ion spins.

5.
Nature ; 465(7298): 590-3, 2010 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-20520708

RESUMO

A network is frustrated when competing interactions between nodes prevent each bond from being satisfied. This compromise is central to the behaviour of many complex systems, from social and neural networks to protein folding and magnetism. Frustrated networks have highly degenerate ground states, with excess entropy and disorder even at zero temperature. In the case of quantum networks, frustration can lead to massively entangled ground states, underpinning exotic materials such as quantum spin liquids and spin glasses. Here we realize a quantum simulation of frustrated Ising spins in a system of three trapped atomic ions, whose interactions are precisely controlled using optical forces. We study the ground state of this system as it adiabatically evolves from a transverse polarized state, and observe that frustration induces extra degeneracy. We also measure the entanglement in the system, finding a link between frustration and ground-state entanglement. This experimental system can be scaled to simulate larger numbers of spins, the ground states of which (for frustrated interactions) cannot be simulated on a classical computer.

6.
Phys Rev Lett ; 105(26): 265703, 2010 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-21231680

RESUMO

A Wigner crystal formed with trapped ions can undergo a structural phase transition, which is determined only by the mechanical conditions on a classical level. Instead of this classical result, we show that through consideration of quantum and thermal fluctuation, a structural phase transition can be driven solely by a change in the system's temperature. We determine a finite-temperature phase diagram for trapped ions using the renormalization group method and the path integral formalism, and propose an experimental scheme to observe the predicted temperature-driven structural phase transition, which is well within the reach of the current ion trap technology.

7.
Phytochemistry ; 53(6): 623-37, 2000 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10746874

RESUMO

This review illustrates the distribution of tropane alkaloids within the families Solanaceae, Erythroxylaceae, Proteaceae, Euphorbiaceae, Rhizophoraceae, Convolvulaceae and Cruciferae. Whereas tropane alkaloids are characteristic of the genera Datura, Brugmansia (tree datura) and Duboisia of the Solanaceae, the distribution is more widespread with novel tropane derivatives in families not traditionally associated with these bases. The chemical nature of more recently discovered water-soluble calystegines and the di- and trimeric forms from the Convolvulaceae (e.g. schizanthines from Schizanthus spp.), truxillines from Bolivian coca leaves and moonines of Erythroxylum moonii are highlighted. Where possible and appropriate, links between the phytochemistry and taxonomy are discussed.


Assuntos
Magnoliopsida/química , Plantas Medicinais/química , Tropanos/química , Brassicaceae/química , Geografia , Rosales/química , Solanaceae/química
8.
Acta Crystallogr D Biol Crystallogr ; 53(Pt 4): 474-6, 1997 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-15299918

RESUMO

The calcium-binding domain of the small subunit of porcine calpain (domain VI) has been expressed in Escherichia coli, purified, and crystallized in the presence of Ca(2+). Two crystal forms have been obtained by the vapor-diffusion method using PEG 6000 as the precipitant. Crystal form I, belonging to trigonal space group P3(1)21 (or P3(2)21) with cell dimensions a = b = 79.8, c = 57.08 A, alpha = beta = 90.0 and gamma, = 120.0 degrees diffracted to 2.8 A. The second crystal form diffracts to 1.8 A and belongs to monoclinic space group P2(1) with cell dimensions a = 50.1, b = 79.7, c = 57.1 A and beta = 91.2 degrees.

9.
Nat Struct Biol ; 4(7): 539-47, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9228946

RESUMO

The three dimensional structure of calcium-bound domain VI of porcine calpain has been determined to 1.9 A resolution. The crystal structure reveals five EF-hands, one more than previously suggested. There are two EF-hand pairs, one pair (EF1-EF2) displays an 'open' conformation and the other (EF3-EF4) a 'closed' conformation. Unusually, a calcium atom is found at the C-terminal end of the calcium binding loop of EF4. With two additional residues in the calcium binding loop, the fifth EF-hand (EF5) is in a 'closed' conformation. EF5 pairs up with the corresponding fifth EF-hand of a non-crystallographically related molecule. Considering the EF5's role in a homodimer formation of domain VI, we suggest a model for the assembly of heterodimeric calpain. The crystal structure of a Ca2+ bound domain VI-inhibitor (PD150606) complex has been refined to 2.1 A resolution. A possible mode for calpain inhibition is discussed.


Assuntos
Acrilatos/metabolismo , Cálcio/metabolismo , Calpaína/química , Calpaína/metabolismo , Acrilatos/química , Sequência de Aminoácidos , Sítios de Ligação , Calpaína/antagonistas & inibidores , Cristalografia por Raios X , Inibidores de Cisteína Proteinase/metabolismo , Dimerização , Modelos Moleculares , Dados de Sequência Molecular , Conformação Proteica , Dobramento de Proteína , Homologia de Sequência de Aminoácidos
10.
Australas Biotechnol ; 2(1): 23-6, 1992 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-1368028

RESUMO

New ways for medicinal plant improvement and for the production of plant drugs have opened up as the result of advances in plant biotechnology and increasing interest in plant-derived pharmaceuticals. This article highlights plant improvement of Duboisia and production of tropane alkaloids using modern techniques such as plant tissue and cell culture, root culture, radioimmunoassay in tropane alkaloid analysis, and molecular biology in the studies of tropane biosynthesis.


Assuntos
Biotecnologia , Plantas Medicinais/metabolismo , Tropanos/metabolismo , Austrália , Células Cultivadas , Técnicas de Cultura , Ornitina/metabolismo , Fenilalanina/metabolismo , Plantas Medicinais/citologia , Plantas Medicinais/crescimento & desenvolvimento , Radioimunoensaio , Escopolamina/metabolismo
11.
Plant Cell Rep ; 11(4): 207-10, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-24202988

RESUMO

The Duboisia hybrid (D. leichhardtii x D. myoporoides) was regenerated from callus derived from shoot tips and young seeds on Murashige and Skoog (MS) medium containing 54µM 1-naphthalenacetic acid (NAA) and 1µM 6-benzylaminopurine (BA). Callus derived from young seeds was superior to shoot tip callus. Buds were induced from callus on MS medium supplemented with 22µM BA. The buds formed shoots when transferred to MS medium with 5 µM BA and 0.5µM NAA. Shoots were induced to form roots when placed on MS medium containing 25 µM indolebutyric acid (IBA). Plantlets so formed were transplanted and subsequently planted out in the open. Approximately 6 months were required for the full regenerative process. Trees so formed have been grown for 3 years, reached a height of 3 metres and flowered and fruited normally.

14.
Sci Sin B ; 30(12): 1280-8, 1987 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-3130658

RESUMO

The orientation and position of the trypsin molecule in the complex crystal cell mung bean trypsin inhibitor Lys fragment (MBILF)-bovine trypsin (BTRY) have been successfully determined by molecular replacement method with the model of the refined bovine trypsin molecule. Starting from the BTRY coordinates which were oriented and located in the correct azimuth and position in the complex cell according to the result from rotation function and translation function, sim-weighted Fourier map with coefficients 2/Fo/-/Fc/ at 3.0 A resolution was calculated. Besides the electron density which is obviously attributed to itself, in the vicinity of the active site of BTRY the dense contour levels corresponding to the MBILF and and its boundary could be clearly seen in this map. The size of MBILF was approximately estimated at 15 x 15 x 25 A.


Assuntos
Fragmentos de Peptídeos/análise , Inibidor da Tripsina de Soja de Bowman-Birk/análise , Inibidores da Tripsina/análise , Cristalografia , Lisina , Tripsina/análise
15.
Sci Sin B ; 28(11): 1163-6, 1985 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-3939264

RESUMO

The Lys fragment of mung bean trypsin inhibitor can combine with bovine trypsin to form a complex at an equal molar ratio. The single crystals of the complex were obtained by using the micro-still-setting method and the X-ray diffraction extended to 1.8A resolution. Its space group is P212121 with cell dimensions a = 62.9(1)A, b = 63.4(1)A and c = 69.7 (2)A. There is one complex molecule in a crystallographic asymmetric unit.


Assuntos
Fragmentos de Peptídeos/análise , Inibidores da Tripsina/análise , Animais , Bovinos , Cristalografia , Fabaceae , Lisina , Plantas Medicinais , Tripsina
17.
J Trauma ; 19(4): 285-7, 1979 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-439187

RESUMO

Traumatic forequarter amputation is rare and extremely mutilating. A 21-year-old male factory worker who sustained a traumatic shoulder girdle amputation is described. The injury mechanism was traction from the machine's force combined with the compressive force on the sternoclavicular joint. The factors leading to survival from this injury include rapid transportation, prompt and effective resuscitation, including treatment of shock, and adequate surgical management. Recognition of the complications associated with retrosternoclavicular dislocation is emphasized.


Assuntos
Amputação Traumática/terapia , Traumatismos do Braço/cirurgia , Lesões do Ombro , Acidentes de Trabalho , Adulto , Amputação Traumática/cirurgia , Humanos , Masculino , Ressuscitação , Choque Traumático/terapia , Fatores de Tempo , Transporte de Pacientes
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