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.

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.

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.

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.