Endothelial Nitric Oxide Synthase Gene Polymorphisms Associated with Susceptibility to High Altitude Pulmonary Edema in Chinese Railway Construction Workers at Qinghai-Tibet over 4500 Meters above Sea Level

Objective To examine whether the polymorphisms of endothelial nitric oxide synthase (eNOS) gene are associated with the susceptibility to high altitude pulmonary edema (HAPE) in Chinese railway construction workers at Qinghai-Tibet where the altitude is over 4 500 m above sea level. Methods A case-control study was conducted including 149 HAPE patients in the construction workers and 160 healthy controls randomly recruited from their co-workers, matching the patients in ethnicity, age, sex, lifestyle, and working conditions. Three polymorphisms of eNOS gene, T-786C in promoter, 894G/T in exon 7, and 27bp variable number tandem repeat (VNTR) in intron 4, were genotyped using polymerase chain reaction (PCR) and confirmed with DNA sequencing. Results The frequencies of 894T allele and heterozygous G/T of the 894G/T variant were significantly higher in HAPE patients group than in the control group (P=0.0028 and P=0.0047, respectively). However, the frequencies of the T-786C in promoter and the 27bp VNTR in intron 4 were not significantly different between the two groups. Haplotypic analysis revealed that the frequencies of two haplotypes (H3,T-T-b, b indicates 5 repeats of 27 bp VNTR; H6, C-G-a, a indicates 4 repeats of 27 bp VNTR) were significantly higher in HAPE patients (both P<0.0001). On the contrary, the frequencies of H1 (T-G-b) and H2 (T-G-a) were lower in HAPE patients than in healthy controls (both P<0.001). Conclusions Two haplotypes (T-T-b and C-G-a) may be strongly associated with susceptibility to HAPE. Compared with the individual alleles of eNOS gene, the interaction of multiple genetic markers within a haplotype may be a major determinant for the susceptibility to HAPE.

A Stable Wavelength Operation Ho:YAG Laser with Orthogonally Polarized Pump

A stable wavelength operation Ho:YAG laser dual-pumped by two orthogonally polarized Tm:YLF lasers is reported. Under the cw operation mode, a laser output power of 24 W is measured. The corresponding opticaloptical conversion efficiency is 44.75% and the slope efficiency is 50.12%. Under the Q-switched operation mode,the output maximum average power is 22.8 W at the re-frequency of 6 kHz. The corresponding optical-optical conversion efficiency and slope efficiency are 42.64% and 48.01%, respectively. The output central wavelength is 2090.73 nm, the linewidth is 0.40 nm, and the beam quality is M^2< 1.6. Moreover, the shift of the output central wavelength is less than 0.01 nm, and the linewidth shift is also less than 0.01 nm.

Wavelength-Locked 878.6 nm In-Band Pumped Intra-Cavity 2.1 μm Optical Parametric Oscillator

We report herein a high-power folded intra-cavity 2.1μm optical parametric oscillator(ICOPO)which is the first example of an ICOPO that utilizes a wavelength-locked 878.6 nm in-band pumped Nd:YVO4 laser as the pump source.The thermal effect of PPMgLN crystal and the divergence angle of the incident laser are considered comprehensively to determine the 2128 nm degenerate temperature.In the experiment,the functions of different output coupler transmittances and different repetition rates on the parametric laser output power are studied,respectively.The temperature versus parametric laser output power in an in-band p umped non-wavelength-locked880 nm laser diode(LD)and in a wavelength-locked 878.6 nm LD is compared.A maximum output power of 5.87 W is obtained at the pump power of 56.9 W when the repetition rate is 80 kHz.The corresponding conversion efficiency is 14.55%,with a linewidth of 73.65 nm and pulse width of 3.62 ns.The wavelength-locked 878.6 nm LD in-band pumping technology can stabilize the 2.1μm laser output power of Nd:YVO4 crystal effectively in the environment of intense temperature change.