[MiR-4484 regulates the expression of integrin α 6 in gastric cancer tissues and its significance].

Objective: To investigate the relationship between the expression of integrin α 6 (ITGA6), miR-4484 and the pathologic stage of gastric cancer. Methods: Gastric cancer tissues and normal gastric mucosa tissues adjacent to cancer (>5 cm from tumor margin) of 30 patients with primary gastric cancer who underwent direct surgical resection without adjuvant therapy from June to September 2017 in West China Hospital of Sichuan University were selected. Real-time quantitative polymerase chain reaction (PCR) was used to detect the expression levels of miR-4484 and ITGA6, western blot was used to detect the expression level of ITGA6 protein, dual luciferase reporter gene was used to verify the relationship between ITGA6 and miR-4484. Spearman's correlation analysis was used to determine the relationship between miR-4484 and ITGA6 expression levels in gastric cancer tissues. Results: The expression level of ITGΑ6 in gastric cancer (32.30±13.47) was higher than that in matched normal gastric tissues (24.55±10.25, P=0.015), the area under the receiver operating characteristic (ROC) curve was 0.660 and the diagnostic sensitivity and specificity were 43.3% and 96.7%, respectively. The expression level of miR-4484 in gastric cancer (4.11±2.87) was lower than that of matched normal gastric tissues (5.75±2.80, P=0.029), the area under the ROC curve was 0.690 and the diagnostic sensitivity and specificity were 30.0% and 86.7%, respectively. The expression level of miR-4484 was negatively correlated with ITGA6 in gastric cancer tissues (r=-0.621, P<0.001). The expression level of ITGA6 protein in gastric cancer tissues (0.65±0.19) was higher than that in normal adjacent tissues (0.26±0.12, P<0.001). Compared with ITGA6 3'UTR wild-type+ miR-NC group, ITGA6 3'UTR wild-type+ miRNA mimics group had lower luciferase activity (50.69±5.10, 34.00±1.19, P<0.001), while the luciferase activity of ITGA6 3'UTR wild-type+ ASO miR-4484 group was higher than that of ITGA6 3'UTR wild-type+ miR-NC group (82.44±6.37, 50.69±5.10, P<0.001), indicated that ITGA6 was the direct target gene of miR-4484. The expression levels of miR-4484 in T1, T2, T3 and T4 (4a and 4b) gastric cancer tissues were 9.98±2.24, 5.28±2.03, 2.92±2.04 and 4.11±2.87, respectively, with statistical significance (P<0.001). The expression levels of ITGA6 in N0, N1, N2 and N3 gastric cancer tissues were 29.55±8.32, 21.71±3.75, 24.60±8.79 and 40.69±15.83, respectively, with statistical significance (P=0.022). The expression levels of miR-4484 in N0, N1, N2 and N3 gastric cancer tissues were 5.01±3.52, 5.48±2.76, 5.88±1.83 and 2.30±1.56, respectively, with statistical significance (P=0.032). The expression levels of ITGA6 in M0 and M1 gastric cancer tissues were 26.28±7.66 and 52.08±8.12, respectively, with statistical significance (P<0.001). The expression levels of miR-4484 in M0 and M1 gastric cancer tissues were 4.95±2.74 and 1.34±0.80, respectively, with statistical significance (P<0.001). Conclusions: ITGA6 is upregulated in gastric cancer tissues, while miR-4484 is downregulated in the gastric cancer group, and its expression level is related to the clinicopathological features of gastric cancer. ITGA6 is the direct target gene of miR-4484, implicates that miR-4484 may inhibit the invasion and metastasis of gastric cancer by regulating the expression of ITGA6. Both miR-4484 and ITGA6 may be the new prognostic markers and potential therapeutic targets of gastric cancer.

Biaxial crystal α-BaTeMo(2)O(9): theory study of large birefringence and wide-band polarized prisms design.

α-BaTeMo(2)O(9) is a novel biaxial crystal with wide-band transmittance spectrum. The refractive index dispersion curves and birefringence of the α-BaTeMo(2)O(9) crystal were obtained in spectral range of 0.4~5 µm. The origin of the birefringence for the crystal has been calculated and interpreted on the basis of the crystal structure combined with theoretical studies. The polarized directions and formulations of refractive index of optical waves in biaxial α-BaTeMo(2)O(9) were investigated by solving the refractive index ellipsoid equations. Furthermore, polarized prisms based on the α-BaTeMo(2)O(9) crystal used in spectral ranges of 0.4~2.7 µm and 0.48~4.5 µm were designed and characterized. The extinction ratios of both prisms were determined to be larger than 10000:1, which would satisfy the practical requirements. The impacts on extinction ratio for biaxial and uniaxial crystals were also discussed. To our knowledge, it is the first report about biaxial crystals for the polarized prisms, and the results show that the α-BaTeMo(2)O(9) crystal is a promising material for polarized optical components, especially in the range of 3~5 µm.

High-efficiency diode-pumped actively Q-switched ceramic Nd:YAG/BaWO4 Raman laser operating at 1666 nm.

A diode-pumped actively Q-switched Raman laser employing BaWO4 as the Raman active medium and a ceramic Nd:YAG laser operating at 1444 nm as the pump source is demonstrated. The first-Stokes-Raman generation at 1666 nm is achieved. With a pump power of 20.3 W and pulse repetition frequency rate of 5 kHz, a maximum output power of 1.21 W is obtained, which is the highest output power for a 1.6 µm Raman laser. The corresponding optical-to-optical conversion efficiency is 6%; the pulse energy and peak power are 242 µJ and 8.96 kW, respectively.

Self-frequency-doubled BaTeMo2O9 Raman laser emitting at 589 nm.

In this paper, the spontaneous Raman spectra and second harmonic generation (SHG) properties at 589 nm of a novel Raman crystal BaTeMo(2)O(9) (BTM) were investigated. The BTM crystal was cut along the type-II SHG phase-matching direction for the first-order Raman shift at 1178 nm to realize the SRS and SHG simultaneously. Pumped by a nanosecond 1064 nm laser source, a self-frequency-doubled BTM Raman laser operating at 589 nm has been demonstrated for the first time. At the pump pulse energy of 48 mJ, the maximum yellow laser output pulse energy of 5.6 mJ was obtained with an optical-to-optical conversion efficiency of 11.7%. Our results show that BTM crystal is one of the promising candidate Raman materials to generate yellow laser radiation.

High efficiency Nd:YAG ceramic eye-safe laser operating at 1442.8 nm.

We report on a diode-pumped Nd:YAG ceramic laser operating at 1442.8 nm for the first time. In our experiment, two different Nd:YAG ceramics with the Nd-doped concentrations of 1.0 and 0.6 at. % and a Nd:YAG with the Nd-doped concentration of 1.0 at. % were used as the laser gain mediums, respectively. At a pump power of 20.7 W, a maximum output power of up to 3.96 W with optical-to-optical efficiency of up to 19.1% was obtained by using the 1.0 at. % Nd-doped ceramic as the laser gain medium. To the best of our knowledge, this is the highest output power of a LD-pumped 1.44 µm Nd:YAG ceramic laser and the highest optical-to-optical efficiency of a LD-pumped 1.44 µm Nd-doped crystal laser.

Dual-wavelength synchronously mode-locked Nd:CNGG laser.

We have experimentally demonstrated a dual-wavelength synchronously mode-locked Nd:CNGG laser based on the semiconductor saturable absorber mirror technique. Mode locking was achieved simultaneously on two gain bands of the crystal that have a central wavelength separation of 2.4 nm. The fundamental mode-locked pulse train has a repetition rate of 88 MHz and pulse duration of 5 ps, with an average output power of approximately 90 mW. Autocorrelation measurements show that each of the synchronously mode-locked pulses consists of a train of quasi-periodic beat pulses with a 660 fs pulse width and a 0.63 THz repetition rate.