[Evaluation of the safety and efficacy of transcatheter aortic valve replacement with domestic prostheses for patients with severely stenotic bicuspid aortic valve].

Objective: To evaluate the safety and efficacy of transcatheter aortic valve replacement (TAVR) with domestic prostheses in patients with severely stenotic bicuspid aortic valve (BAV). Methods: This study was a prospective single-center non-randomized controlled study. Patients with symptomatic severe aortic stenosis (AS), who underwent TAVR with domestic prostheses at the First Affiliated Hospital of Air Force Medical University from January 2016 to April 2020 were consecutively included in our study. Patients were divided into BAV group and tricuspid aortic valve (TAV) group according to the aortic valve morphology. Baseline characteristics, procedural outcomes were compared between the two groups, and the primary endpoint was one-month all-cause mortality. Results: A total of 100 patients aged (69.8±8.9) years were enrolled, including 71 (71%) males. There were 51 cases in BAV group and 49 cases in TAV group. Compared with TAV group, patient in the BAV group was younger ((67.1±8.6) years vs. (72.7±8.4) years, P=0.002) and had larger ascending aortic diameter at proximal part ((39.7±5.7) mm vs. (36.0±4.2) mm, P<0.001), lower Society of Thoracic Surgeons-Predicted Risk of Mortality (STS-PROM) score (3.1 (1.9, 5.4) % vs. 5.9 (2.6, 12.3) %, P=0.002). In BAV group and TAV group, the incidence of 2nd prosthesis implantation was 15.7% (8/51) and 18.4% (9/49) (P=0.721), the incidence of moderate or severe paravalvular regurgitation was 2.0% (1/51) and 0 (P=1.000), the rate of device success was 82.4% (42/51) and 81.6% (40/49) (P=0.925), respectively. One-month all-cause mortality was 2.0% (1/51) and 10.2% (5/49) (P=0.108), respectively. Echocardiography showed that postprocedural mean pressure gradient (PGmean) was higher in the BAV group (13.0 (10.0, 16.0) mmHg vs. 9.0 (7.0, 14.0) mmHg, P=0.003) (1 mmHg=0.133 kPa), but the PGmean decrease post procedure as compared with that before TAVR was similar between the two groups ((36.7±16.6) mmHg vs. (36.2±17.5) mmHg, P=0.893). Conclusion: Favorable safety and efficacy are evidenced in patients with severely stenotic BAV undergoing TAVR with domestic prostheses.

Generation and propagation of hyperbolic secant solitons, Peregrine solitons, and breathers in a coherently prepared atomic system.

We study the generation and propagation of hyperbolic secant solitons, Peregrine solitons, and various breathers in a coherently prepared three-level atomic system, where two lower states are coherently prepared prior to the injection of a strong pump field and a weak probe field. We show that a flat dispersion without gain and loss along with a large Kerr nonlinearity can be achieved in a broad range of probe field frequency. Moreover, optical hyperbolic secant solitons can be easily achieved in such a broad range at a very low light intensity and propagate stably. Due to the enhanced Kerr nonlinearity, we also show that it is possible to generate optical rogue waves and breathers with very weak light stimulus, which is three orders of magnitude smaller than that used in nonlinear fibers. Because the gain/absorption is negligible and the quantum noise of the probe field can be significantly suppressed, our work may pave the way for realizing solitons, rogue waves, and breathers at the quantum level.

Squeezed Light Induced Symmetry Breaking Superradiant Phase Transition.

We theoretically investigate the quantum phase transition in the collective systems of qubits in a high quality cavity, where the cavity field is squeezed via the optical parametric amplification process. We show that the squeezed light induced symmetry breaking can result in quantum phase transition without the ultrastrong coupling requirement. Using the standard mean field theory, we derive the condition of the quantum phase transition. Surprisingly, we show that there exists a tricritical point where the first- and second-order phase transitions meet. With specific atom-cavity coupling strengths, both the first- and second-order phase transition can be controlled by the nonlinear gain coefficient, which is sensitive to the pump field. These features also lead to an optical switching from the normal phase to the superradiant phase by just increasing the pump field intensity. The signature of these phase transitions can be observed by detecting the phase space Wigner function distribution with different profiles controlled by the squeezed light intensity. Such superradiant phase transition can be implemented in various quantum systems, including atoms, quantum dots, and ions in optical cavities as well as the circuit quantum electrodynamics system.

Sensing single atoms in a cavity using a broadband squeezed light.

We investigate a single atom cavity-QED system directly driven by a broadband squeezed light. We demonstrate how the squeezed radiation can be used to sense the presence of a single atom in a cavity. This happens by transferring one of the photons from the field in a state with an even number of photons to the atom and thereby populating an odd number of Fock states. Specifically, the presence of the atom is sensed by remarkable changing in the presence of one photon and the loss of squeezing of the cavity field. A complete study of quantum fluctuations and the excitation of multiphoton transitions is given.

Dynamic Onset of Feynman Relation in the Phonon Regime.

The Feynman relation, a much celebrated condensed matter physics gemstone for more than 70 years, predicts that the density excitation spectrum and structure factor of a condensed Bosonic system in the phonon regime drops linear and continuously to zero. Until now, this widely accepted monotonic excitation energy drop as the function of reduced quasi-momentum has never been challenged in a spin-preserving process. We show rigorously that in a light-matter wave-mixing process in a Bosonic quantum gas, an optical-dipole potential arising from the internally-generated field can profoundly alter the Feynman relation and result in a new dynamic relation that exhibits an astonishing non-Feynman-like onset and cut-off in the excitation spectrum of the ground state energy of spin-preserving processes. This is the first time that a nonlinear optical process is shown to actively and significantly alter the density excitation response of a quantum gas. Indeed, this dynamic relation with a non-Feynman onset and cut-off has no correspondence in either nonlinear optics of a normal gas or a phonon-based condensed matter Bogoliubov theory.

Zero to π Continuously Controllable Cross Phase Modulation in Doppler Broadened N-Type Electromagnetically Induced Transparency Medium.

We demonstrate an observation of zero to π continuously controllable cross-phase-modulation based on N-type electromagnetically induced transparency scheme in a room-temperature 87Rb vapor. We theoretically and experimentally show that the signal field acquires a π phase shift compared with the reference light in the presence of the phase-control field. Using the method of the optical Mach-Zehnder interferometer, we demonstrate that a zero to π continuously controllable phase gate can be built by modulating the phase-control field. In addition, our theoretical calculation agrees well with the experimental observation, and the results presented in this work hold the potential applications for the orthogonal polarization/vector gate in the quantum information processing.

Dynamic ultraslow optical-matter wave analog of an event horizon.

We investigate theoretically the effects of a dynamically increasing medium index on optical-wave propagation in a rubidium condensate. A long pulsed pump laser coupling a D2 line transition produces a rapidly growing internally generated field. This results in a significant optical self-focusing effect and creates a dynamically growing medium index anomaly that propagates ultraslowly with the internally generated field. When a fast probe pulse injected after a delay catches up with the dynamically increasing index anomaly, it is forced to slow down and is prohibited from crossing the anomaly, thereby realizing an ultraslow optical-matter wave analog of a dynamic white-hole event horizon.

Upregulation and nuclear translocation of testicular ghrelin protects differentiating spermatogonia from ionizing radiation injury.

Proper control of apoptotic signaling is important for maintenance of testicular homeostasis after ionizing radiation (IR). Herein, we challenged the hypothesis that ghrelin, a pleiotropic modulator, is potentially involved in IR-induced germ cell injury. Lower body exposure to 2 Gy of IR induced a notable increase of ghrelin expression in the nuclear of differentiating spermatogonia at defined stages, with an impairment in the Leydig cells (LCs)-expressing ghrelin. Unexpectedly, inhibition of the ghrelin pathway by intraperitoneal injection of a specific GHS-R1α antagonist enhanced spermatogonia elimination by apoptosis during the early recovery following IR, and thereafter resulted in impaired male fertility, suggesting that the anti-apoptotic effects of evoked ghrelin, although transient along testicular IR injury, have a profound influence on the post-injury recovery. In addition, inhibition of ghrelin signaling resulted in a significant increase in the intratesticular testosterone (T) level at the end of 21 days after IR, which should stimulate the spermatogenic recovery from surviving spermatogonia to a certain extent during the late stage. We further demonstrated that the upregulation and nuclear trafficking of ghrelin, elaborately regulated by IR-elicited antioxidant system in spermatogonia, may act through a p53-dependent mechanism. The elicitation of ghrelin expression by IR stress, the regulation of ghrelin expression by IR-induced oxidative stress and the interaction between p53 and ghrelin signaling during IR injury were confirmed in cultured spermatogonia. Hence, our results represent the first evidence in support of a radioprotective role of ghrelin in the differentiating spermatogonia. The acutely, delicate regulation of local-produced ghrelin appears to be a fine-tune mechanism modulating the balance between testicular homeostasis and early IR injury.

Clinical value of surfactant protein-A in serum and sputum for pulmonary tuberculosis diagnosis.

The aim of this study was to explore the diagnostic and differential diagnosis value of surfactant protein-A (SP-A) in the serum and sputum for pulmonary tuberculosis. A total of 101 patients with pulmonary tuberculosis, 85 healthy volunteers, and 30 chronic obstructive pulmonary disease (COPD) patients were divided into pulmonary tuberculosis group, healthy control group, and COPD group, respectively. SP-A was determined in the serum and sputum in the three groups by enzyme-linked immunosorbent assay. The expression of SP-A in serum was significantly higher (P < 0.05) in the pulmonary tuberculosis group than in the healthy control and COPD groups. There were no differences in the SP-A expression in the sputum among the three groups. There was no significant effect of gender, age, tubercle bacillus antibodies, tuberculin purified protein derivative trial, leukocyte count, neutrophilic granulocyte, lymphocyte percentage, or lung cavities on SP-A levels in serum or sputum for the pulmonary tuberculosis group (P > 0.05). The detection of SP-A in serum and sputum was shown to be of great value for the diagnosis and differential diagnosis of pulmonary tuberculosis, and therefore merits further investigation.

Scaffold evaluation of liguzinediol analogs as novel cardiotonic agents.

Liguzinediol (LZDO) could mediate the positive inotropic effects through sarcoplasmic reticulum Ca2+ ATPase-dependent mechanism without the risk of arrhythmia. However, the pharmacophore of LZDO contributed to the activities was not clear. The aim of this work was to explore the relationship between positive inotropic effect and scaffold of LZDO as well as to check whether the pharmacophore of LZDO on anti-heart failure activity was located at the pyrazine ring. A series of LZDO analogs (3a-b, 4a-b, 9-19) were designed and synthesised, and their activities were evaluated on isolated heart contractility by Langendorff perfusion. The results showed that the efficacy of LZDO was reduced when the hydroxyl, carboxyl or ester moieties at the side chain position of LZDO were induced, and the para-dihydroxy in LZDO was necessary for its activity. Thus, the pharmacophore of the positive inotropic effect might be located at the whole scaffold of LZDO, but not at the pyrazine ring. The finding may provide an important clue of the pharmacophore for the development of novel cardiotonic agents.

Many-body dipole-dipole interactions between excited Rb atoms probed by wave packets and parametric four-wave mixing.

Dipole-dipole interactions between excited Rb atoms at long range (approximately 300a0-2150a0) have been observed with molecular wave packets and a coherent nonlinear optical process. Fourier analysis of the parametric four-wave mixing (PFWM) signal wave intensity produced in femtosecond pump-probe experiments demonstrates the appearance of sidebands associated with the Rb 7s-5d(5/2) quantum beating frequency of approximately 18.3 THz. Calculations show that the observed sideband splittings and Fourier domain profiles result from multiple atom, dipole-dipole interactions, and ensembles comprising five or fewer Rb (7s, 6p) atoms account for virtually all of the data.

Generation of synchronized femtosecond and picosecond pulses in a dual-wavelength femtosecond Ti:sapphire laser.

We obtain synchronized 45-fs and 0.848-ps pulses by achieving cross-mode locking in a double-cavity dual-wavelength femtosecond Ti:sapphire laser. Autocorrelation and cross correlation show that the femtosecond and picosecond pulses are well synchronized, with a timing jitter of 41 fs. Cross-phase modulation dominates the processes of cross-mode locking and synchronization.

Endothelial progenitor cells' "homing" specificity to brain tumors.

Current treatment of malignant glioma brain tumors is unsatisfactory. Gene therapy has much promise, but target-specific vectors are needed. Endothelial progenitor cells (EPCs) have in vivo homing specificity to angiogenic sites and are thus potential vehicles for site-specific gene therapy. However, reports of EPCs "homing" to intracranial solid tumors are lacking. We investigated EPCs' "homing" specificity using a murine intracranial glioma model. EPCs, derived from human cord blood, were labeled with a fluorogenic agent CFSE and intravenously injected into SCID mice bearing orthotopic gliomas. At 7-14 days after EPC injection, mouse brains and other vital organs were examined for distribution of transplanted EPCs. As controls, CFSE-labeled human umbilical vein endothelial cells (HUVECs) and EPCs were intravenously injected into matched glioma SCID mice (HUVEC control groups) and nontumor SCID mice (nontumor-bearing control groups), respectively. Fluorescence image analysis revealed that systemically transplanted EPCs 'homed' to brain tumors with significantly higher specificity as compared to other organs within the experimental group (P<0.001) and to anatomically matched brain sections from the control groups (P<0.001). Our study demonstrates EPCs' in vivo tropism for intracranial gliomas, with potential for cell delivery of brain tumor spatial-specific gene therapy.

Steric hindrance as a mechanistic probe for olefin reactivity: variability of the hydrogenic canopy over the isomeric adamantylideneadamantane/sesquihomoadamantene pair (a combined experimental and theoretical study).

Access to each C=C face of adamantylideneadamantane (AA) and sesquihomoadamantene (SA) is hindered by the hydrogenic canopy consisting of four beta-hydrogens; otherwise, these olefins have quite normal environments. X-ray crystallography and density functional (DFT) calculations show a 0.5 A larger annular opening in the protective cover of AA than that in SA. This contributes to the remarkable differences in reactivity toward various reagents, not only by limiting access to the olefin site in SA but also by inhibiting reactions which force these hydrogens closer together. Thus, AA is subject to typical olefin-addition reactions with bromine, sulfuryl chloride, m-chloroperbenzoic acid, dioxygen, and so forth, albeit sometimes at attenuated rates. On the other hand, SA is singularly unreactive under identical reaction conditions, except for the notable exceptions that include Brønsted (protonic) acids, a nitrosonium cation, and dichlorine. The exceptions are characterized as three sterically limited (electrophilic) reagents whose unique reactivity patterns are shown to be strongly influenced by steric access to the C=C center. As such, the different degrees of steric encumbrance in the isomeric donors AA and SA shed considerable light on the diverse nature of olefinic reactions. In particular, they evoke mechanistic features in electrophilic addition versus electron transfer, which are otherwise not readily discernible with other less hindered olefinic donors. Transient structures of the olefinic-reaction intermediates such as the protonated carbocations AA-H+ and SA-H+ as well as the cation radicals AA*+ and SA*+ are probed by the combination of X-ray crystallographic analyses and density functional theoretical computations.

Bioequivalence evaluation of two sertraline tablet formulations in healthy male volunteers after a single dose administration.

SUBJECTS, MATERIAL AND METHODS: According to a randomized two-period crossover design, 12 Chinese male volunteers were treated with 2 sertraline tablet formulations, one was made in China as test tablet, the other was made in England as reference tablet. Each volunteer received each sertraline in a single dose of 150 mg. The 2 medications were carried out by a wash-out phase of 23 days. Blood samples were obtained just before dosing and at 10 time points until 96 hours after administration, and plasma sertraline concentrations were determined by a sensitive gas-chromagraphy electron-capture method with a lower limit of quantification of 0.625 ng/ml. The bioequivalence of 2 formulations was evaluated by the shortest 90% confidence interval method which corresponds to the two one-sided test method. RESULTS: The point estimate (90% confidence interval) of the mean ratio (test/reference) for AUC(0-96) was 97.19% (82.66% to 122.33%), for Cmax 96.27% (83.64% to 121.36%), and for t(l/2) 96.31% (85.43% to 119.57%). Regarding Tmax (test-reference), the 90% confidence interval ranged from -4 to +4 hours, but the difference between the Tmax values of 2 products is clinically of minor importance. CONCLUSION: Therefore, it can be concluded that 2 sertraline tablet formulations are bioequivalent. administration, sertraline is slowly absorbed with peak plasma concentrations at 6 - 8 h, and has a terminal elimination half-life of approximately 26 h, indicating once-daily dosing is available. Clinically, it can be taken either in the morning or in the evening, with or without food [Ronfeld et al. 1997b]. In addition, it also exhibits higher plasma protein binding up to 97% and extensive first-pass metabolism. By demethylation, sertraline is metabolized primarily to N-demethylsertraline, and then eliminated by hydroxylation arid conjugation [Tremaine et al. 1989]. This study aimed at assessing of bioequivalence of two sertraline formulations (produced in China and England, respectively) in healthy male volunteers after a single dose administration.

Measurement of biological activity of somatotropin in hypophysectomized rats.

AIM: To develop a method for measurement of biological activity of recombinant DNA-derived somatotropin (rhGH). METHODS: The effects of varying the route, frequency and period of administration of GH, the sex of test animals on the biological responses, body weight gain (BWG), and tibial epiphyseal width (TEW), of hypophysectomized (Hypox) rats were compared, respectively. 4-d BWG, 6-d BWG, and 6-d TEW tests were carried out simultaneously in the same group of Hypox rats to determine the biopotency of GH preparations according to a parallel line bioassay (6-point assay). The final result was chosen from the test which had smaller values for the index of precision (lambda) and the average rate of fiducial limits (ARFL) than other tests. RESULTS: No significant differences in the responses between male and female rats, between sc and im, once daily and twice daily injections of bGH were found. But the BWG and TEW of Hypox rats injected with 0.045 and 0.135 IU.d-1 of bGH for 6 d were significantly greater than that for 4 d. Both 4-d BWG test and 6-d BWG test in the range from 0.020 to 0.500 IU.d-1 had values for lambda = 0.0660 and 0.1747, and for r = 0.9000 and 0.9237, respectively. Three estimates of rhGH preparation compared with the International Standard for somatotropin (IShGH), 4.6132, 3.9829, and 4.8023 IU/ampoule, were obtained separately from 4-d BWG test, 6-d BWG test and 6-d TEW test. And the result from 6-d BWG test was reported finally because it had smaller values for lambda and ARFL (0.0608 and 37.907%) than other two tests. CONCLUSION: Both BWG test and TEW test can be carried out simultaneously in the same group of Hypox rats. 6-d BWG test seemed to be more suitable for potency determination of GH preparations than 4-d BWG test and 6-d TEW test.

[Pharmacokinetics of gentamicin after intratracheal administration in tracheotomy patients].

Seventeen tracheotomy patients were given gentamicin (Gen) into trachea at the dosage of 2 and 4 mg.kg-1. Gen concentration in serum was determined by fluorescence polarization immunoassay. Pharmacokinetic parameters were calculated by micro-computer pharmacokinetic program (MCPKP). T1/2Ka, Tp, and Cmax were 0.6 +/- 0.3 h, 1.7 +/- 0.7 h, and 4.6 +/- 1.8 micrograms.ml-1, respectively in 4 mg.kg-1 group and 0.3 +/- 0.3 h, 0.9 +/- 0.5 h, and 0.4 +/- 0.2 microgram.ml-1, respectively in 2 mg.kg-1 group (P < 0.05). T1/2Kel was 30 +/- 11 h in patients of serum creatine (Cr) > 2 mg% and 6 +/- 5 h in patients of Cr < 2 mg% (P < 0.01). No significant difference could be found between Cmax of different renal function patients (P > 0.05).