Hypermethylation of GSTM5 and its effect on oxidation in myelodysplastic syndrome

Background:Hypermethylation of glutathione-S-transferase 5(GSTM5)and its effect on oxidation in the pathogenesis of myelodysplastic syndrome(MDS)were investigated.Methods:GSTM5 methylation was detected in bone marrow(BM)samples from MDS patients,acute myeloid leukemia(AML)patients,and control in-dividuals using methylation-specific PCR and MassARRAY analysis.Bisulfite sequencing PCR was performed to verify methylation levels,while mRNA levels were determined using reverse transcription polymerase chain reaction.Correlations between GSTM5 methylation and clinical parameters were analyzed.The MDS cell line,SKM-1,was treated with decitabine,buthionine sulfoximine,or overexpression of GSTM5,and the glutathione level and cell viability were detected.Results:The MassARRAY analysis revealed significant differences in GSTM5 methylation levels between the MDS and control groups.GSTM5 methylation levels were significantly increased in the high-risk subgroup and showed a significant association with MDS progression to AML(hazard ratio=3.6).Levels of GSTM5 mRNA were significantly decreased in the MDS group,exhibiting a negative correlation with the GSTM5 gene methylation level.Normal BM HS-5 cells exhibited significantly lower levels of GSTM5 methylation than SKM-1 cells.Overexpression of GSTM5 in SKM-1 cells or treatment with buthionine sulfoximine or decitabine resul-ted in inhibition of proliferation and significantly decreased glutathione levels.Conclusions:GSTM5 plays an anti-oxidative role in MDS and the tumor suppressor effect of GSTM5 may be mediated by reducing glutathione levels.GSTM5 hypermethylation and low levels of GSTM5 expression may be prog-nostic markers for MDS.

Effects of Casimir force on high-order sideband generation in an optomechanical system

We introduce a Casimir force in a conventional optomechanical system to study the high-order sideband gen- eration. In this system, a nanosphere is placed near the moveable mirror of the conventional optomechanical system. The moveable mirror is coupled to the cavity field and the nanosphere by the optomechanical interaction and the Casimir interaction, respectively. We find that the amplitude and cutoff order of the high-order sideband can be enhanced by decreasing the sphere-mirror separation （increasing the Casimir force） and increasing the optomechanical coupling strength. Our proposal provides an alternative method for generating the high-order sidebands and for measuring the Casimir force.

Phase modulation polarization encoding module applied to one-to-many QKD network based on wavelength division multiplexing

The quantum key distribution(QKD)network is a promising solution for secure communications.In this paper,we proposed a polarization-independent phase-modulated polarization encoding module,and it can be combined with a dense wavelength division multiplexer(DWDM)to achieve multi-user QKD.We experimentally test the encoding module with a repetition rate of 62.5 MHz,and its average quantum bit error rate(QBER)is as low as 0.4%.Finally,we implement a principle verification test for simultaneous QKD for 1 to 2 users in 100 min,and the average QBER of two users under the transmission distance of 1 km and 5 km is kept below 0.8%.Due to the use of polarization encoding,the module can also realize scalable network architecture in free-space QKD systems in the future.