Single-Atom Verification of the Optimal Trade-Off between Speed and Cost in Shortcuts to Adiabaticity.

The approach of shortcuts to adiabaticity enables the effective execution of adiabatic dynamics in quantum information processing with enhanced speed. Owing to the inherent trade-off between dynamical speed and the cost associated with the transitionless driving field, executing arbitrarily fast operations becomes impractical. To understand the accurate interplay between speed and energetic cost in this process, we propose theoretically and verify experimentally a new trade-off, which is characterized by a tightly optimized bound within s-parametrized phase spaces. Our experiment is carried out in a single ultracold ^{40}Ca^{+} ion trapped in a harmonic potential. By exactly operating the quantum states of the ion, we execute the Landau-Zener model as an example, where the quantum speed limit as well as the cost are governed by the spectral gap. We witness that our proposed trade-off is indeed tight in scenarios involving both initially eigenstates and initially thermal equilibrium states. Our work helps understanding the fundamental constraints in shortcuts to adiabaticity and illuminates the potential of underutilized phase spaces that have been traditionally overlooked.

Energy-Conversion Device Using a Quantum Engine with the Work Medium of Two-Atom Entanglement.

Although entanglement is considered as an essential resource for quantum information processing, whether entanglement helps for energy conversion or output in the quantum regime is still lack of experimental witness. Here, we report on an energy-conversion device operating as a quantum engine with the working medium acted by two entangled ions confined in a harmonic potential. The two ions are entangled by virtually coupling to one of the vibrational modes shared by the two ions, and the quantum engine couples to a quantum load, which is another shared vibrational mode. We explore the energy conversion efficiency of the quantum engine and investigate the useful energy (i.e., the maximum extractable work) stored in the quantum load by tuning the two ions in different degrees of entanglement as well as detecting the change of the phonons in the load. Our observation provides, for the first time, quantitative evidence that entanglement fuels the useful energy produced by the quantum engine, but not helpful for the energy conversion efficiency. We consider that our results may be useful to the study of quantum batteries for which one of the most indexes is the maximum extractable energy.

Enhancement of Quantum Heat Engine by Encircling a Liouvillian Exceptional Point.

Quantum heat engines are expected to outperform the classical counterparts due to quantum coherences involved. Here we experimentally execute a single-ion quantum heat engine and demonstrate, for the first time, the dynamics and the enhanced performance of the heat engine originating from the Liouvillian exceptional points (LEPs). In addition to the topological effects related to LEPs, we focus on thermodynamic effects, which can be understood by the Landau-Zener-Stückelberg process under decoherence. We witness a positive net work from the quantum heat engine if the heat engine cycle dynamically encircles a LEP. Further investigation reveals that a larger net work is done when the system is operated closer to the LEP. We attribute the enhanced performance of the quantum heat engine to the Landau-Zener-Stückelberg process, enabled by the eigenenergy landscape in the vicinity of the LEP, and the exceptional point-induced topological transition. Therefore, our results open new possibilities toward LEP-enabled control of quantum heat engines and of thermodynamic processes in open quantum systems.

Phospholipase C signaling is involved in porcine reproductive and respiratory syndrome virus infection in cell cultures.

The phospholipase C (PLC) is a family of kinases that hydrolyze phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] to generate two second messengers, inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG), which stimulate distinct downstream signaling. Recently, it has been reported that PLC signaling is activated by multiple viruses for efficient replication and the virus-induced inflammatory response. In this study, we demonstrated that PLC-specific inhibitor U73122 strongly suppressed porcine reproductive and respiratory syndrome virus (PRRSV) productive infection in cell cultures. The inhibitor affected both viral post-binding cell entry and post-entry processes. The virus infection led to an early transient activation of PLCγ-1 at 0.5 h post-infection (hpi), and sustained event at a stage from 4 to 16 hpi in MARC-145 cells. In addition, U73122 inhibited the activation of p38 MAPK signaling stimulated by PRRSV infection, suggesting that PLC signaling may be associated with the virus infection-induced inflammatory response. Taken together, these studies suggested that PLC signaling played an important role in PRRSV infection or pathogenesis. Keywords: PRRSV; U73122; phospholipase C; PLCγ-1.

Isolation and sequence analysis of the complete VP2 gene of canine parvovirus from Chinese domestic pets and determination of the pathogenesis of these circulating strains in beagles.

Canine parvovirus (CPV) causes acute gastroenteritis in domestic dogs, cats, and several wild carnivore species. In this study, the full-length VP2 gene of 36 CPV isolates from dogs and cats infected between 2016 and 2017 in Beijing was sequenced and analyzed. The results showed that, in dogs, the new CPV-2a strain was the predominant variant (n = 18; 50%), followed by the new CPV-2b (n = 6; 16.7%) and CPV-2c (n = 3; 8.3%) strains, whereas, among cats, the predominant strain was still CPV-2 (n = 9; 25%). One new CPV-2a strain, 20170320-BJ-11, and two CPV-2c strains, 20160810-BJ-81 and 20170322-BJ-26, were isolated and used to perform experimental infections. Multiple organs of beagles that died tested PCR positive for CPV, and characteristic histopathological lesions were observed in organs, including the liver, spleen, lungs, kidneys, small intestines, and lymph nodes. Experimental infections showed that the isolates from the epidemic caused high morbidity in beagles, indicating their virulence in animals and suggesting the need to further monitor evolution of CPV in China.

Recombinant avian adeno-associated virus-mediated oviduct-specific expression of recombinant human tissue kallikrein.

Human tissue kallikrein (hK1) plays an important role in regulation of blood pressure, electrolyte and glucose transport, and renal function. To evaluate the feasibility of viral vector-mediated expression of recombinant human tissue kallikrein (rhK1) in the egg white of laying hens, human tissue kallikrein gene (hKLK1) cDNA-expression cassette was subcloned into avian adeno-associated virus (AAAV) transfer vector pAITR and transfected into AAV-293 cells with AAAV helper vector pcDNA-ARC and adenovirus helper vector pHelper. The recombinant viral particles with a typical AAAV morphology and relatively high titer were generated and identified by PCR and electron microscopy. After 1 intravenous injection of each laying hen with 2 x 10(10) viral particles, oviduct-specific expression of hKLK1 cDNA was demonstrated by reverse transcription-PCR. Secretion of rhK1 into the egg white was detected by enzymatic assay from d 2, reaching the highest level of 107 U/mL in wk 3, and lasted for more than 6 wk after injection. Western blotting showed that the oviduct-expressed rhK1 had the same molecular mass with the natural enzyme. These data suggest that rAAAV can mediate high level and long-lasting transgene expression in oviduct cells, and the established expression system is useful for production of other recombinant proteins.

Invasive pulmonary aspergillosis in patients with chronic obstructive pulmonary disease: a case control study from China.

Patients with severe chronic obstructive pulmonary disease (COPD) are at higher risk of developing invasive pulmonary aspergillosis (IPA). However, there are limited data for this disease. To evaluate risk factors and the clinical characteristics of IPA in COPD patients, we conducted a hospital-based, retrospective case-control study of 30 COPD patients with IPA and 60 COPD control patients without IPA. Patients in the case group were significantly more likely to have concurrent co-morbidities than controls. Of the IPA patients, 65.4% had worsening radiological findings vs. 11.4% in the control group (p<0.001). IPA in COPD was associated with a higher proportion of mechanical ventilation (43.3% vs. 5%; p<0.001), a longer hospital stay duration (45.8±39.1 days vs. 18.4±11.8 days; p<0.001), and higher mortality (43.3% vs. 11.4%; p<0.001). Systemic use of steroids in the stable phase, treatment with three or more antibiotics during hospitalization and antibiotic treatment longer than 10 days were independent risk factors associated with IPA. COPD patients with obvious dyspnoea, antibiotic-resistant lower respiratory tract infection and repeated detection of Aspergillus in sputum should be considered for the possibility of IPA.

PEGylated polycyanoacrylate nanoparticles as salvicine carriers: synthesis, preparation, and in vitro characterization.

AIM: To synthesized poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) with polyethylene glycol (PEG, Mr = 5000), prepare PEGylated PHDCA and poly(n-hexadecyl cyanoacrylate) (PHDCA) nanoparticles loading salvicine and determine their in vitro characterizations. METHODS: The structure of PEGylated PHDCA was determined with 1H-NMR, 13C-NMR and Fourier transform infrared spectrum (FTIR). Its molecular weight was determined by gel permeation chromatography (GPC). Nanoparticles were prepared by emulsion/solvent evaporation method. RESULTS: 1H-NMR, 13C-NMR, and FTIR were consistent with structure of PEGylated PHDCA, whose average molecular weight is 6680. Entrapment efficiency could be determined by high pressure liquid chromatography (HPLC) method without endogenous interference at the retention time of salvicine. The entrapment efficiency was 92.6 % for PEGylated PHDCA nanoparticles and 98.9 % for PHDCA nanoparticles. The nanoparticles size was about 250 nm. The values of the zeta potential were obviously influenced by the composition of the copolymer. Compared with PHDCA nanoparticles (-23.1 mV), PEGylated PHDCA nanoparticles showed a low surface potential (-9.6 mV). Salvicine release from nanoparticles showed an initial burst effect, then a plateau for an extended period, and finally sustained release phase. CONCLUSION: These results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for salvicine delivery in the respect of anti-tumor potency.