The clinical characteristics and treatment outcomeof 57 children and adolescents with primary central nervoussystem germ cell tumors

Primary central nervous system germ cell tumors(CNS-GCTs) in children and adolescents have unique clinical features and methods of treatment compared with those in adults. There is little information about Chinese children and adolescents with CNS-GCTs. Therefore, in this study we retrospectively analyzed the clinical features and treatment outcome of Chinese children and adolescents with primary CNS-GCTs. Between January 2002 and December 2012, 57 untreated patients from a single institution were enrolled. They were diagnosed with CNS-GCTs after pathologic or clinical assessment. Of the 57 patients, 41 were males and 16 were females, with a median age of 12.8 years(range, 2.7 to 18.0 years) at diagnosis; 43(75.4%) had non-germinomatous germ cell tumors(NGGCTs) and 14(24.6%) had germinomas; 44(77.2%) had localized disease and 13(22.8%) had extensive lesions. Fifty-three patients completed the prescribed treatment, of which 18 underwent monotherapy of surgery, radiotherapy, or chemotherapy, and 35 underwent multimodality therapies that included radiotherapy combined with chemotherapy or surgery combined with chemotherapy and/or radiotherapy. PEB(cisplatin, etoposide, and bleomycin) protocol was the major chemotherapy regimen. The median follow-up time was 32.3 months(range, 1.2 to 139 months). Fourteen patients died of relapse or disease progression. The 3-year event-free survival(EFS) and overall survival rates for all patients were 72.2% and 73.8%, respectively. The 3-year EFS was 92.9% for germinomas and 64.8% for NGGCTs(P = 0.064). The 3-year EFS rates for patients with NGGCTs who underwent monotherapy and multimodality therapies were 50.6% and 73.5%, respectively(P = 0.042). Our results indicate that multimodality therapies including chemotherapy plus radiotherapy were better treatment option for children and adolescents with CNS-GCTs.

Quantum speed limit for the maximum coherent state under the squeezed environment

The quantum speed limit time for quantum system under squeezed environment is studied.We consider two typical models,the damped Jaynes-Cummings model and the dephasing model.For the damped Jaynes-Cummings model under squeezed environment,we find that the quantum speed limit time becomes larger with the squeezed parameter r increasing and indicates symmetry about the phase parameter valueθ=π.Meanwhile,the quantum speed limit time can also be influenced by the coupling strength between the system and environment.However,the quantum speed limit time for the dephasing model is determined by the dephasing rate and the boundary of acceleration region that interacting with vacuum reservoir can be broken when the squeezed environment parameters are appropriately chosen.

Quantum speed limit of a single atom in a squeezed optical cavity mode

We theoretically study the quantum speed limit of a single atom trapped in a Fabry-Perot microresonator.The cavity mode will be squeezed when a driving laser is applied to the second-order nonlinear medium,and the effective Hamiltonian can be obtained under the Bogoliubov squeezing transformation.The analytical expression of the evolved atom state can be obtained by using the non-Hermitian Schr¨odinger equation for the initial excited state,and the quantum speed limit time coincides very well for both the analytical expression and the master equation method.From the perspective of quantum speed limit,it is more conducive to accelerate the evolution of the quantum state for the large detuning,strong driving,and coupling strength.For the case of the initial superposition state,the form of the initial state has more influence on the evolution speed.The quantum speed limit time is not only dependent on the system parameters but also determined by the initial state.

Margolus-Levitin speed limit across quantum to classical regimes based on trace distance

The classical version of Mandelstam-Tamm speed limit based on theWigner function in phase space was reported by Shanahan et al.[Phys.Rev.Lett.120070401(2018)].We present the Margolus-Levitin speed limit across the quantumto-classical transition in phase space based on the trace distance.The Margolus-Levitin speed limit is set by the Schatten L1 norm of the generator of time-dependent evolution for both the quantum and classical domains.As an example,the time-dependent harmonic oscillator is considered to illustrate the result.

Prevalence and genotype of Chlamydia psittaci in faecal samples of birds from zoos and pet markets in Kunming, Yunnan, China

Chlamydia psittaci is an important zoonotic pathogen in birds and may be transmitted to humans and result in severe respiratory disease. To assess the prevalence and genotype of C. psittaci in birds in Kunming, Yunnan, China, a total of 136 specimens of psittacine birds involving 8 species were collected from the city＇s zoos （n=60） and pet markets （n=76）. The frequency of C. psittaci infection was 19.9% （27/136） in the psittacine birds. The prevalence of C. psittaci was higher in pet birds （26.3%; 20/76） than in zoo birds （11.7%; 7/60） （P=0.034）. In particular, among Agapornis fischeri, the C. psittaci infection （50%; 10/20） was significantly more frequent in the pet markets than in the zoos （P=-0.006）. In addition, the highest prevalence of 41.2% （7/17） was found in Ara ararauna. To determine the genotype of C. psittaci, 23 OmpA gene fragments （about 1.4 kb） in 27 positive samples were successfully amplified and sequenced. Phylogenetic analysis showed that all the 23 strains belonged to genotype A. Our results demonstrate the high prevalence of C. psittaci genotype A infection in psittacine birds in Yunnan Province, suggesting a potential threat to human health in this area. Therefore, it is necessary to take effective measures to prevent the spread of C. psittaci among psittacine birds, as well as among employees and customers.