Nanosecond pulsed deep-red laser source by intracavity frequency-doubled crystalline Raman laser.

We demonstrated a deep-red laser source by intracavity frequency-doubled crystalline Raman laser for the first time, to the best of our knowledge. The actively Q-switched 1314 nm Nd:LiYF4 laser was first converted to the eye-safe Raman laser using a KGd(WO4)2 (KGW) crystal, which was subsequently frequency-doubled in a bismuth borate crystal. Benefiting from the KGW bi-axial properties, the deep-red laser source was able to lase separately at two different spectral lines at 730 and 745 nm. Under an optimal repetition rate of 4 kHz, the maximum average powers of 1.7 and 2.0 W were attained with good beam quality of M2≈1.7. The corresponding pulse durations were determined to be 3.0 and 2.8 ns with the peak powers up to approximately 140 and 180 kW, respectively.

Single-longitudinal-mode cascaded crystalline Raman laser at 1.7 µm.

A single-longitudinal-mode crystalline Raman laser in the 1.7 µm wave band was reported for the first time, to the best of our knowledge. The YVO4 Raman laser, which was intracavity-pumped by an actively Q-switched 1314 nm Nd:YLF laser, demonstrated the cascaded Stokes oscillation at 1715 nm. By inserting an etalon in the fundamental resonator, linewidth narrowing and power scaling of the second-Stokes laser were realized based on the spatial-hole-burning-free Raman gain. With an optimal pulse repetition frequency of 4 kHz, the maximum single-longitudinal-mode average output power of 1.8 W was acquired with the spectrum linewidth of ∼340MHz. Further increasing the incident pump power, the second-Stokes laser transitioned to multimode regime, and the maximum average output power reached 2.7 W with the peak power as high as ∼380kW.

High-peak-power narrowband eye-safe intracavity Raman laser.

We demonstrated a narrowband eye-safe intracavity Raman laser by incorporating a fused silica etalon into the fundamental resonator. The KGd(WO4)2 (KGW) Raman laser was pumped by an actively Q-switched Nd:YLF laser at 1314 nm. Thanks to the KGW bi-axial properties, two distinct eye-safe Raman lasers operating at 1461 and 1490 nm were obtained separately by rotation of the KGW crystal. At an optimized pulse repetition frequency of 4 kHz, the maximum average output powers of 3.6 and 4.0 W were achieved with the peak powers up to approximately 330 and 480 kW, respectively. The eye-safe Stokes emissions were narrow linewidth (∼0.05 nm FWHM; measurement limited) and near diffraction limited (M2 < 1.4). The powerful narrowband eye-safe Raman lasers are of interest for applications as diverse as laser range finding, scanning lidar and remote sensing.

High-peak-power eye-safe orthogonally-polarized dual-wavelength Nd:YLF/KGW Raman laser.

An actively Q-switched eye-safe orthogonally-polarized dual-wavelength intracavity Raman laser was demonstrated for the first time, to the best of our knowledge. The gain balanced dual-wavelength operation at 1314 and 1321 nm within an in-band pumped Nd:YLF laser was realized by slightly titling the cavity mirrors. Owing to the KGW bi-axial properties, two sets of simultaneous orthogonally-polarized dual-wavelength Raman lasers at 1470, 1490 nm and 1461, 1499 nm were achieved by simply rotating the KGW crystal for 90°, respectively. With an incident pump power of 30 W and an optimized pulse repetition frequency of 5 kHz, the maximum dual-wavelength Raman output powers of 2.6 and 2.4 W were obtained with the pulse widths of 5.8 and 6.3 ns, respectively, corresponding to the peak powers up to 89.7 and 76.5 kW.

[Genetic Screening of Thalassemia among the Couples of Childbearing Age in Ding'an County of Hainan Province and Its Analysis].

OBJECTIVE: To investigate the gene-carrying rate and genetic types of thalassemia among the couples of child-bearing age in Ding'an, Hainan province. METHODS: A total of 1742 couples at child bearing age in the region were screened for thalassemia by detecting the mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV). If the sample data of either spouse of couples was tested as MCV＜82 fl and /or MCH＜27 pg, both samples of the couple would be further assayed by hemoglobin electrophoresis. Those samples of HbA2 2.5 % or HbA2＞3.5 % were judged as positive in the preliminary screening, then subjected to genetic diagnosis of thalassemia. RESULTS: 478 cases out of 1 742 couples of child bearing age were diagnosed as thalassemia gene mutation, and the gene-carrying rate was 13.72 %. In those carriers, 42 couples were diagnosed with the same type of thalassemia, accounting for 3.67 %. The gene-carrying rate of α-thalassemia, ß-thalassemia and αß-thalassemia was 9.56%, 3.10% and 1.06 % respectively. CONCLUSION: The Ding'an area in Hainan Province is an area with high incidence of thalassemia, and the main genotype is α-thalassemia, showing a distribution of local characteristics. The government should make efferts to popularise the screening for thalassemia, so as to effectively prevent the birth of children with thalassemia major.

Frequency expansion of orthogonally polarized dual-wavelength laser by cascaded stimulated Raman scattering.

In this Letter, the frequency expansion of an orthogonally polarized dual-wavelength laser, based on the cascaded stimulated Raman scattering, was demonstrated for the first time, to the best of our knowledge. The dual-wavelength fundamental laser generated from two separate Nd:YLF crystals was free of gain competition. Integrating the benefit of the two different orthogonally polarized Raman gain peaks in the KGd(WO4)2 (KGW) crystal, two sets of first-Stokes orthogonally polarized dual-wavelength Raman lasers were first achieved by rotating the Raman crystal for 90°. Furthermore, by simply replacing the Raman output coupler, we attained another two sets of second-Stokes orthogonally polarized dual-wavelength Raman lasers via the cascaded Raman shift. At a pulse repetition frequency of 5 kHz, the maximum first-Stokes and second-Stokes dual-wavelength Raman output powers were 3.12 and 2.09 W, with the combined peak powers of approximately 240 and 290 kW, respectively.

[Analysis of Genetic Screening in Couples of Reproductive Age for Thalassemia in Lingshui Li Autonomous County of Hainan Province].

OBJECTIVE: To investigate the genetic carrier rate of thalassemia and its gene mutation types as well as the distribution characteristics among the people in Lingshui Li autonomous county of Hainan province, so as to provide the basis for making the prevention programs of thalassemia in administrative departments. METHODS: Samples were collected from couples undergoing premarital and pregestational screenings, in which the positive ones in preliminary screening were further tested by genetic diagnoses and the genotypes were analyzed. RESULTS: The rate of thalassemia gene carriers was 19.41% （274/1412） of the couples of childbearing age in Lingshui Li autonomous County of Hainan Province. In these carriers,α-thalassemia accounted for 83.21%（228/274）, ß-thalassemia for 8.03%（22/274）, and both α-and ß-thalassemia gene accounted for 8.76% （28/274）. CONCLUSION: The carrying rate of thalassemia gene in population Lingshui Li autonomous county of Hainan province is high, and its distribution has geographical characteristics,the major type is α-thalassemia. Blood screening and genetic diagnosis of thalassemia should be strengthened, and corresponding measures should be taken to reduce its gene frequency.

Clinical application of oligo array-CGH for detecting balanced translocations in preimplantation genetic diagnosis.

Array comparative genomic hybridization (array-CGH), which facilitates to detect unbalanced reciprocal translocation and allows screening aneuploidy for chromosomes, has been repeatedly verified to be valid for diagnosis of translocations in preimplantation human embryos. Currently, the main microarrays used for CGH are bacterial artificial chromosome (BAC)-based arrays. Compared with the BAC-based arrays, oligonucleotide (oligo)-based arrays have a relatively higher resolution and optimal coverage particularly in the subtelomeric regions. Herein, we described the clinical application of a newly designed oligo-based array by Agilent in preimplantation genetic diagnosis (PGD) and aneuploidy screening for balanced translocations. In the study, a total of 144 embryos from 9 couples carrying Robertsonian translocations and 5 carrying reciprocal translocations were biopsied on day 3 for array-CGH analysis. Overall, 135 (93.8%) embryos were successfully diagnosed to be free of either aneuploidies or unbalanced fragments. However, the remained 9 (6.2%) embryos failed to be amplified due to failed cell lysis, DNA damage or the absence of nuclei in the biopsied cells. Collectively, 23 embryos were identified as "euploid and balanced" and suitable to be transferred. Finally, 9 embryos of satisfactory quality were transferred to 6 women, among which 4 recipients exhibited positive hCG level. Fortunately, one recipient with positive hCG level has delivered one baby, and two pregnancies were continuing. Our study served as the first clinical application of oligo-based array CGH technology in PGD for both reciprocal and Robertsonian translocations concomitant with comprehensive aneuploidy screening.

[Detection of Carbon Dioxide Concentration in Soil Profile Based on Nondispersive Infrared Spectroscopy Technique].

In order to explore the variation of CO2 concentration and soil respiration in soil profile, the nondispersive infrared (NDIR) spectroscopy technique was applied to continually estimate the soil CO2 concentration in different soil layers (the humus horizon, A-, B-, C-horizon) in situ. The main instrument used in this experiment was silicon-based nondispersive infrared sensor, which could work in severe environment. We collected the Measurement value by NDIR spectroscopy technique throughout 2013. The values of soil carbon flux in different soil layers were calculated based on the model of gradient method and calibrated by measuring with an automated soil CO2 efflux system (LI-8100). The results showed that: a vertical gradient for the carbon dioxide concentration in soil profile was found, and the concentration was highest in the deepest soil horizon. Moreover, A linear correlation between the soil CO2 effluxes was calculated based on model and measurement, and the model prediction correlation coefficient was 0.9069, 0.7185, 0.8382, and 0.9030 in the H-, A-, B-, and C-horizon, respectively. The roots of mean square error (RMSE) were 0.2067, 0.1041, 0.0156, and 0.0096 in the H-, A-, B-, and C-horizon, respectively. These results suggest that the gradient method based on the NDIR spectroscopy technique can be successfully used to measure soil CO2 efflux in different soil layers, which reveal that diffusion and convection transport CO2 between the soil layers. It is a promising sensor for detecting CO2 concentration in soil profile, providing the basic data for calculating the global carbon in soil profile.

Survivin gene functions and relationships between expression and prognosis in patients with nasopharyngeal carcinoma.

This study aimed to investigate the relationship between prognosis and protein and mRNA expression of an apoptotic inhibitor gene, survivin, in patients with nasopharyngeal carcinoma. Furthermore, functions of the survivin gene in the CNE2 nasopharyngeal carcinoma cell line were assessed. Immunohistochemistry and in situ hybridization were used in detecting the survivin protein and mRNA in 44 nasopharyngeal carcinoma specimens, and 30 chronic nasopharyngitis samples as controls. Survivin gene expression in CNE2 cell line was suppressed with an shRNA (short hairpin RNA). The positive ratios of expression for survivin protein and mRNA in nasopharyngeal carcinoma were 79.5% and 75.0% respectively, obviously higher than in the control group (p<0.01), and there is very good consistency between the two methods. The mean survival time of patients with higher survivin protein or mRNA expression was shorter than in patients with lower levelsv(p<0.01). Proliferation of the CNE2 cell line was distinctly inhibited by the shRNA . The results indicate that overexpression of the survivin gene plays an important role in onset and development of nasopharyngeal carcinoma, and it may be helpful for prognostic appraisal.

[Study on the expression of survivin mRNA and protein in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the relationship between survivin mRNA and protein expression and nasopharyngeal carcinoma (NPC). METHODS: Survivin mRNA and protein were detected by in situ hybridization and immunohistochemical S-P staining respectively. RESULTS: Among 64 cases of NPC, 42 cases (65.6%) were positive for survivin mRNA expression, 30 cases (46.9%) had high expression level. In 46 cases (71.9%) of NPC were positive for survivin protein expression, and 38 cases (59.4%) had high expression level. In 22 cases of NPC with detailed clinical information, the positive expression rates of survivin mRNA and protein in stages III+ IV of NPC were 66.7% and 61.1% respectively, which were higher than those in stages I+ II of NPC (50.0% and 50.0% respectively). There was no significant difference between survivin mRNA and protein expression regarding age or gender of NPC patients (all P> 0.05). The positive expression rates of survivin mRNA and protein in chronic nasopharyngitis group were 33.3% and 23.3% respectively, which were lower than those in NPC group (chi (2)= 12.04, P< 0.01 and chi (2)= 19.57, P< 0.01, respectively). In 64 cases of NPC, 36 cases were positive for both survivin mRNA and protein, and the expression of survivin mRNA and protein showed positive correlation (phi = 0.43). CONCLUSION: The expression of survivin gene may play some roles in the pathogenesis of NPC. Detection of survivin mRNA and protein will be helpful for diagnosis, clinical staging and prognosis of NPC.