299 research outputs found
The Behavior of House on Seasonally Frozen Ground
This paper presents a case history of instrumented house with shallow foundation on the seasonally frozen ground. Variations of the soil frost penetration, the soil temperature, the cracks of the house, the displacements and the contact pressure on the base were systematically observed during freezing and thawing periods. It has been confirmed that the main reason why the cracks of the houses with shallow foundations occurred is that the development of the frozen depth is not uniform and the frost heaving and the redistribution of the contact pressures are unequal. This paper puts forward the principle of the effective depth of frost heaving and a new concept of foundation design method, which is adopted in the Chinese Code TJ7-74
Singularity in classical and quantum Kepler Problem with Weak Anisotropy
Anisotropic Kepler problem is investigated by perturbation method in both
classical and quantum mechanics. In classical mechanics, due to the singularity
of the potential, global diffusion in phase space occurs at an arbitrarily
small perturbation parameter. In quantum mechanics, the singularity induces a
large transition amplitude between quasi degenerate eigen states, which
generically decays as in the semi-classical limit.Comment: 6 pages, 2 figures, 1 tabl
Functional Characterization of Arabidopsis PHL4 in Plant Response to Phosphate Starvation
Plants have evolved an array of adaptive responses to cope with phosphate (Pi) starvation. These responses are mainly controlled at the transcriptional level. In Arabidopsis, PHR1, a member of the MYB-CC transcription factor family, is a key component of the central regulatory system controlling plant transcriptional responses to Pi starvation. Its homologs in the MYB-CC family, PHL1 (PHR1-LIKE 1), PHL2, and perhaps also PHL3, act redundantly with PHR1 to regulate plant Pi starvation responses. The functions of PHR1’s closest homolog in this family, PHL4, however, have not been characterized due to the lack of its null mutant. In this work, we generated two phl4 null mutants using the CRISPR/Cas9 technique and investigated the functions of PHL4 in plant responses to Pi starvation. The results indicated that the major developmental, physiological, and molecular responses of the phl4 mutants to Pi starvation did not significantly differ from those of the wild type. By comparing the phenotypes of the phr1 single mutant and phr1phl1 and phr1phl4 double mutants, we found that PHL4 also acts redundantly with PHR1 to regulate plant Pi responses, but that its effects are weaker than those of PHL1. We also found that the overexpression of PHL4 suppresses plant development under both Pi-sufficient and -deficient conditions. Taken together, the results indicate that PHL4 has only a minor role in the regulation of plant responses to Pi starvation and is a negative regulator of plant development
Non-Markovian Quantum Gate Set Tomography
Engineering quantum devices requires reliable characterization of the quantum
system including qubits, quantum operations (aka instruments) and the quantum
noise. Recently, quantum gate set tomography (GST) has emerged as a promissing
technique to self-consistently describe the quantum states, gates and
measurements. However, non-Markovian correlations between the quantum system
and environment cause the reliability regression of GST. It is essential to
simultaneously describe the gate set and non-Markovian correlations. To this
end, we first propose a self-consistent operational method, named instrument
set tomography (IST), for non-Markovian GST. Based on the stochastic quantum
process, the instrument set is defined to describe instruments, the initial
state, and non-Markovian system-environment (SE) correlations. First, we
propose a linear inversion IST (LIST) to detect and describe the disharmony of
linear relationship of instruments and SE correlations with gauge freedom.
However, LIST cannot always determine physical implementable instrument set
because of the absence of constraints. Then, a physically constrained
statistical method based on the miximum likelihood estimation for IST (MLE-IST)
is proposed with polynomial number of parameters with respect to the Markovian
order. It shows significant flexibility that suit for different types of
device, e.g. noisy intermediate-scale quantum (NISQ) devices, by adjusting the
model and constraints. The experimental results show the effectiveness of
describing instruments and the non-Markovian quantum system. As a result, the
IST provides an essential method for benchmarking and developing quantum
devices in the aspect of instrument set
Clinical Study Improved Outcome of Biliary Atresia with Postoperative High-Dose Steroid
Objective. The dosage, duration, and the benefits of high-dose steroid treatment and outcome in biliary atresia (BA) remain controversial. In this study, we evaluated the impact of high-dose steroid therapy on the outcome of BA after the Kasai procedure. Methods. Intravenous prednisolone administration was started 1 week after surgery, followed by 8 to 12 weeks of oral prednisolone. Total bilirubin (TB) levels (3, 6, and 12 months after surgery), early onset of cholangitis, and two-year native liver survival were evaluated. Results. 53.4%, 56.9%, and 58.1% of the patients in the high-dose steroid group were jaundice-free 3, 6, and 12 months after surgery, respectively; these values were significantly higher than the 38.7%, 39.4%, and 43.3% of the low-dose steroid group. One year after surgery, the incidence of cholangitis in the high-dose group (32.0%) was lower than that in the low-dose group (48.0%). Infants with native liver in the high-dose group had a better two-year survival compared to those in the low-dose steroid group (53.7% versus 42.6%). Conclusions. The high-dose steroid protocol can reduce the incidence of cholangitis, increase the jaundice-free rate, and improve two-year survival with native liver after the Kasai operation
A Novel Soluble Tin(IV) Porphyrin Modified Single-Walled Carbon Nanotube Nanohybrid With Light Harvesting Properties
A dihydroxotin(IV) porphyrin functionalized single-walled carbon nanotubes (SWNTs) nanohybrid is obtained. Solubility of the nanohybrid in organic solvents is determined by UV-Vis-NIR absorption spectroscopy. Electron absorption and fluorescence spectra investigations demonstrate that efficient electron transfer occurs within the nanohybrid at the photoexcited state and the charge-separated state of the nanohybrid is observed by transient absorption spectrum. The results illustrate that this soluble electron donor–acceptor nanohybrid might be a good candidate as a light harvesting material in molecular photoelectronic devices
A new tool for in vitro culture of porcine eggs
Mineral oil is usually used to cover the microdrops of medium in oocytes or embryos culture system here designated as oil method. A large number of oocytes are needed for the production of porcine embryos for in vitro fertilization or somatic cell nuclear transfer (SCNT). The oil method not only wastes a lot of mineral oil, but needs tedious steps in the transferring of embryos. Here we designed a new method called nest dish, which need not mineral oil, to replace the oil method and improve the development rates of porcine eggs in vitro. The oocyte maturation rate with the mTCM199 (83.2%) was significantly higher than with the NCSU23 (75.5%, P﹤ 0.05), although the parthenogenetic cleavage rates with two media were not significantly different (77.7 and 72.4%, P﹤ 0.05 ). Chosing mTCM199 as base medium, the rate of maturation with concave dish (90.1%) was significantly higher than with the flat dish (82.6%, P﹥ 0.05) in nest method, although no significant differences in the oocyte maturation were found between flat dish (82.6%) in nest method and oil method (80.0%). Parthenogenetic cleavage from nest method (80.1% for concave dish, 78.0% for flat dish) did not show any decrease compared to oil method (76.2%), but the developmental rate to blastocysts in the nest groups(17.9 and 19.5%) were significantly higher than the oil method (12.3%, P﹤ 0.05). These results showed that mTCM199 presented higher maturation rate than that NCSU-23 did, and the nest method with concave dish significantly improved the maturation rate of porcine oocytes in vitro and can replace the conventional oil method.Keywords: Porcine oocytes, in vitro maturation (IVM), microdrop method, nest dish metho
Effects of intra-aortic balloon pump on cerebral blood flow during peripheral venoarterial extracorporeal membrane oxygenation support
BACKGROUND: The addition of an intra-aortic balloon pump (IABP) during peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) support has been shown to improve coronary bypass graft flows and cardiac function in refractory cardiogenic shock after cardiac surgery. The purpose of this study was to evaluate the impact of additional IABP support on the cerebral blood flow (CBF) in patients with peripheral VA ECMO following cardiac procedures. METHODS: Twelve patients (mean age 60.40 ± 9.80 years) received VA ECMO combined with IABP support for postcardiotomy cardiogenic shock after coronary artery bypass grafting. The mean CBF in the bilateral middle cerebral arteries was measured with and without IABP counterpulsation by transcranial Doppler. The patients provided their control values. The mean CBF data were divided into two groups (pulsatile pressure greater than 10 mmHg, P group; pulsatile pressure less than 10 mmHg, N group) based on whether the patients experienced cardiac stun. The mean cerebral blood flow in VA ECMO (IABP turned off) alone and VA ECMO with IABP support were compared using the paired t test. RESULTS: All of the patients were successfully weaned from VA ECMO, and eight patients survived to discharge. The addition of IABP to VA ECMO did not change the mean CBF (251.47 ± 79.28 ml/min vs. 251.30 ± 79.47 ml/min, P = 0.96). The mean CBF was higher in VA ECMO alone than in VA ECMO combined with IABP support in the N group (257.68 ± 97.21 ml/min vs. 239.47 ± 95.60, P = 0.00). The addition of IABP to VA ECMO support increased the mean CBF values significantly compared with VA ECMO alone (261.68 ± 82.45 ml/min vs. 244.43 ± 45.85 ml/min, P = 0.00) in the P group. CONCLUSION: These results demonstrate that an IABP significantly changes the CBF during peripheral VA ECMO, depending on the antegrade blood flow by spontaneous cardiac function. The addition of an IABP to VA ECMO support decreased the CBF during cardiac stun, and it increased CBF without cardiac stun
Molybdenum Disulfide-Coated Lithium Vanadium Fluorophosphate Anode: Experiments and First-Principles Calculations
To develop a new anode material to meet the increasing demands of lithium-ion battery, MoS2 is used for the first time to modify the C/LiVPO4F anode to improve its lithium-storage performance between 3 and 0.01 V. Morphological observations reveal that the MoS2-modified C/LiVPO4F particles (M-LVPF) are wrapped by an amorphous carbon as interlayer and layered MoS2 as external surface. Charge–discharge tests show that M-LVPF delivers a high reversible capacity of 308 mAh g−1 at 50 mA g−1. After 300 cycles at 1.0 A g−1, a capacity retention of 98.7 % is observed. Moreover, it exhibits high rate capability with a specific capacity of 199 mAh g−1 at 1.6 A g−1. Electrochemical impedance spectroscopy tests indicate that the lithium-ion diffusion and charge-exchange reaction at the surface of M-LVPF are greatly enhanced. First-principles calculations for the MoS2 (001)/C/LiVPO4F (010) system demonstrate that the absorption of MoS2 on C/LiVPO4F is exothermic and spontaneous and that the electron transfer at the MoS2-absorbed C/LiVPO4F surface is enhanced.postprin
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