[Tunable Diode Laser Absorption Spectroscopy (TDLAS) Detection Signal Denoising Based on Gabor Transform].

Tunable diode laser absorption spectroscopy (TDLAS) technology combined with wavelength modulation spectroscopy (WMS) technology is an important technique for trace gas detection. Detected with the lock-in amplifier, the second harmonic signal obtained after demodulation is analyzed to get the gas absorption information. However, the second harmonic signal is affected by noise which reduces the accuracy and stability of the detection system. To improve the signal to noise ratio (SNR) of the TDLAS detection system, a denoising method based on Gabor transform is proposed for second harmonic signal noise reduction. Taking the CH4 absorption spectrum at 1 653.72 nm as an example, the effectiveness of the noise reduction method is verified through simulation and experiments. The simulation results show that the signal to noise ratio for the second harmonic signal of 0 dB can be improved 15.73 dB with Gabor transform-based denoising method. Experimental results show that with the Gabor transform-based denoising method, the linear correlation coefficient r can be as high as 0.996 59 between the second harmonic peak value and the CH4 concentration in the range of 0.001%~0.02%. At the same time, the detection accuracy and stability of the system have been improved significantly.

[Methane Concentration Detection System for Cigarette Smoke Based on TDLAS Technology].

Rapid and real-time analysis of cigarette smoke is of great significance to study the puff-by-puff transfer rules in the suction process and to explore the relationship between smoking and health. By combining with the modified commercial smoking machine herein, cigarette smoke online analysis system was established based on the TDLAS technology. The puff-by-puff stability of this system was verified by simulated cigarette composed of a pocket containing CH4 (volume fraction of 0.4), of which the second harmonic peaks are near 1.39. Using this system, the concentration of CH4 in four different kinds of cigarettes was analyzed puff-by-puff by a semiconductor laser, of which center wavelength was at 1 653.72 nm. The results showed that the CH4 concentration of cigarette smoke increased puff-by-puff. CH4 concentration in the flue-cured cigarette is obviously higher than that of blended cigarette by comparing the content of all and puff-by-puff concentration. The puff-by-puff concentration of flue-cured cigarette increased from 400 to 900 ppm, however, the puff-by-puff concentration of blended cigarette increased from 200 to 600 ppm. Simultaneously, there was significant difference between different kinds of the flue-cured. Comparing to tradi- tional analysis methods, this system can effectively avoid the interference of other gases in the smoke cigarette as a result of its strong anti-interference. At the same time, it can finish analysis between suction interval without sample pretreatment. The technology has a good prospect in the online puff-by-puff analysis of cigarette smoke.

[Clinical effectiveness of INSURE method in the treatment of neonatal respiratory distress syndrome].

OBJECTIVE: To evaluate the clinical effectiveness and safety of intubation-surfactant-extubation (INSURE) method in the treatment of neonatal respiratory distress syndrome (NRDS), and to investigate its possible mechanisms. METHODS: Sixty-four premature infants, who were admitted for NRDS and treated with pulmonary surfactant from March 2010 to March 2012, were enrolled in the study. They were randomly divided into INSURE (n=32) and conventional mechanical ventilation (CMV) groups (n=32). The two groups were compared in terms of respiratory function, ventilation time, duration of oxygen therapy, complications, and prognosis, as well as expression of interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α) and serum ferritin (SF). RESULTS: Oxygenation index in the INSURE group was significantly higher than in the CMV group at 48 hours after treatment (P<0.05). Compared with the CMV group, the INSURE group showed significantly lower incidence of ventilator-associated pneumonia (VAP) and significantly shorter duration of oxygen therapy (P<0.05 for all comparisons). There were no significant differences in ventilation time and the incidence of pneumothorax, intracranial hemorrhage, necrotizing enteroolitis, bronchopulmonary dysplasia, and pneumorrhagia between the two groups (P>0.05). The levels of TNF-α and SF were significantly lower in the INSURE group than in the CMV group at 6, 24, 48, and 72 hours after treatment (P<0.05), while the level of IL-10 was significantly higher in the INSURE group than in the CMV group (P<0.05). CONCLUSIONS: INSURE method can improve the oxygenation function of the lung, decrease the incidence of VAP and shorten the duration of oxygen therapy in neonates with NRDS, which is probably due to the fact that this method can reduce the production of TNF-α and SF and inhibit the decrease of IL-10.

Eph receptors and ephrins as targets for cancer therapy.

Eph receptor tyrosine kinases and their ephrin ligands are involved in various signalling pathways and mediate critical steps of a wide variety of physiological and pathological processes. Increasing experimental evidence demonstrates that both Eph receptor and ephrin ligands are overexpressed in a number of human tumours, and are associated with tumour growth, invasiveness and metastasis. In this regard, the Eph/ephrin system provides the foundation for potentially exciting new targets for anticancer therapies for Eph-expressing tumours. The purpose of this review is to outline current advances in the role of Eph receptors and ephrin ligands in cancer, and to discuss novel therapeutic approaches of anticancer therapies.

Lgr5 is a potential marker of colorectal carcinoma stem cells that correlates with patient survival.

BACKGROUND: Lgr5 (leucine-rich-repeat-containing G-protein-coupled receptor 5) has recently been identified as an intestinal stem cell marker. In order to determine whether Lgr5 is a potential marker of cancer stem cells, we investigated whether Lgr5 expression correlated with Ki-67 expression and prognosis in colorectal carcinoma. METHODS: Lgr5 and Ki-67 expression were evaluated by immunohistochemistry in 192 colorectal carcinoma specimens. Selection of side population (SP) cells was performed by staining with Hoechest 33342, and Lgr5 expression in Colo205 SP cells was then detected by immunofluorescence. RESULTS: Lgr5 expression was significantly higher in carcinoma than in normal mucosa (P=0.001). Lgr5 was positively correlated with histological grade (P=0.001), depth of invasion (P=0.001), lymph node metastasis (P=0.001), distant metastasis (P=0.004), pTNM stage (P=0.001), and Ki-67 (r=0.446, P=0.001). Multivariate analysis showed that the effect of Lgr5 on survival was independent of Ki-67 (P=0.037). In the in vitro study, Hoechst low-staining cells were counted in 7% of the Colo205 colon cancer cell line population, and Lgr5 expression was strikingly stronger in Hoechst low-staining cells than in high-staining cells (P=0.001). CONCLUSIONS: These findings suggest that Lgr5 may play an important role in the progression and prognosis of colorectal carcinoma, and may be a potential new therapeutic target for the treatment of colorectal cancer patients. It may also be considered as a potential marker for colorectal cancer stem cells (CSCs).

Ion irradiation induced structural and electrical transition in graphene.

The relationship between the electrical properties and structure evolution of single layer graphene was studied by gradually introducing the gallium ion irradiation. Raman spectrums show a structural transition from nano-crystalline graphene to amorphous carbon as escalating the degree of disorder of the graphene sample, which is in correspondence with the electrical transition from a Boltzmann diffusion transport to a carrier hopping transport. The results show a controllable method to tune the properties of graphene.

Identification of miR-4644 as a suitable endogenous normalizer for circulating miRNA quantification in hepatocellular carcinoma.

Background: Circulating microRNAs (miRNAs) have proved to be promising biomarkers for early diagnosis and therapeutic monitoring in cancers. Particularly for hepatocellular carcinoma (HCC), detection of circulating miRNA biomarkers as a new diagnostic approach has been written into the latest Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China (2019 edition). However, no general consensus on an ideal endogenous normalizer for circulating miRNAs quantification has been reached, so it will affect the accuracy of quantitative results. In this study, we aim to identify a stable endogenous normalizer for analyzing circulating miRNAs. Methods: Candidate miRNAs were selected by screening dataset GSE104310, as well as data statistics and analysis. Five commonly reference genes were chosen for further comparison and verification. Then, the expression levels of these genes in serum were analyzed by quantitative reverse transcription PCR (RT-qPCR) among four groups, including patients diagnosed with HCC, chronic hepatitis B (CHB), liver cirrhosis, and healthy subjects. Furthermore, the stability of target genes was evaluated using geNorm, NormFinder, comparative ΔCq programs, and validated by database. We also explored the availability of the miRNA combination, and compared the performance difference between combination and individuals, as well as the selectivity of miRNA references in the combinations. Results: 11 candidate miRNAs were obtained, and miR-4644 stood out among these miRNAs, and proved to be much more stable than other endogenous miRNAs. Further study showed that miR-4644 exhibited higher stability and expression abundance than other commonly miRNA reference controls. Finally, we discovered the combination of miR-4644 and miR-16 revealed high performance in stability when compared to miRNA individuals. Furthermore, the combination consisted of references with closer nature could give rise to amplification effects in stability. Conclusions: Our findings demonstrated that miR-4644 is an ideal endogenous normalizer for circulating microRNA quantification in hepatocellular carcinoma. Besides, combining miR-4644 with miR-16 into a whole as a reference control would greatly improve the accuracy of quantification.

Tocilizumab promotes corneal allograft survival in rats by modulating Treg-Th17 balance.

AIM: To examine the therapeutic effects of tocilizumab on experimental corneal transplantation and its effect on Treg/Th17 balance. METHODS: Allograft corneal graft was performed between host Sprague Dawley and Wistar donor rats. The rats were randomly divided into four groups: normal, autograft, allograft, and allograft treated with tocilizumab. Kaplan-Meier was performed to draw the survival curve. The protein levels of interleukin-17A (IL-17A), vascular endothelial growth factor (VEGF), and forkhead box protein 3 (Foxp3) were measured by immunohistochemistry. The mRNA levels of IL-17A, VEGF, retinoid-related orphan receptor gammat (RORγt), interleukin-6 (IL-6) and Foxp3 were detected by reverse transcription real-time polymerase chain reaction (RT-PCR). The Treg and Th17 cells were investigated by flow cytometry. RESULTS: The survival time of tocilizumab group was (24±1.27d) longer than that of allograft group (10±0.55d). Moreover, immunohistochemical examination revealed that IL-17A and VEGF protein levels in the allograft group were significantly higher than that of tocilizumab group (P<0.01), while Foxp3 levels in the allograft group was significantly lower than that of the tocilizumab treated group (P<0.001). Flow cytometry showed that the number of Th17 cells in allograft group was significantly higher than that in tocilizumab group (P<0.001). Meanwhile, the number of Tregs was significantly lower than in tocilizumab group (P<0.001). Simultaneously, Foxp3 mRNA expression level in corneal tissues of tocilizumab treated group was significantly higher than other groups (P<0.001). CONCLUSION: These findings suggest that tocilizumab may promote corneal allograft survival, possibly by modulating Treg-Th17 balance.

[Corrigendum] Increased expression of Lgr5 is associated with chemotherapy resistance in human gastric cancer.

An interested reader drew to the attention of the Journal that the western blot featured in Fig. 3B of the above paper also appeared as Fig. 3D in the following publication, featuring many of the same authors: Xi HQ, Cai AZ, Wu XS et al: Leucine­rich repeat­containing G­protein­coupled receptor 5 is associated with invasion, metastasis, and could be a potential therapeutic target in human gastric cancer. Br J Cancer 110: 2011­2020, 2014. After having consulted the authors about this matter, they conceded that there was a data sharing violation here, and that the image should not have been reproduced in the above article without having received the prior permission of the British Journal of Cancer. This permission has now been sought after and obtained, and Fig. 3 is reproduced opposite, now including the appropriate credit for the original source of Fig. 3B. The authors apologize to the Editors of the British Journal of Cancer and Oncology Reports, and to the readership for any inconvenience caused. [the original article was published in Oncology Reports 32: 181­188, 2014; DOI: 10.3892/or.2014.3204].

[Role of stromal cell-derived factor-1 and CXC chemokine receptor 4 in corneal graft rejection in rats].

OBJECTIVE: To examine expression of stromal cell-derived factor-1 (SDF-1) and CXC chemokine receptor 4 (CXCR4) in rat cornea tissue and their role in corneal allograft rejection. METHODS: With 15 Wistar rats as the normal control group, 22 Wistar rats received autologous corneal graft transplantation, and 44 Wistar rats received transplantation of corneal graft from SD rats with penetrating keratoplasty. From the rats with allograft transplantation, 22 were selected randomly for treatment with TobraDex eye drops for 30 days after the operation (twice a day), and the remaining 22 rats were treated with normal saline only. Clinical assessment of the corneal grafts was carried out using Larkin's method; histopathological observation, immunohistochemistry, and real-time quantitative PCR of the corneal grafts were performed on days 5 and 9 after the transplantation. RESULTS: Graft rejection occurred in none of the rats in autograft group. In rats treated with TobraDex, the graft survival time was significantly longer than that in rats with saline treatment (24∓0.32 vs 10∓0.36 days, P<0.001), and histopathological examination revealed numerous inflammatory cells and neovascularization in the allografts in the latter group. SDF-1 and CXCR4 mRNA expression in the corneal tissue increased significantly in rats receiving allograft transplantation and saline treatment (P<0.001 on day 5 and P<0.01 on day 5), and their expression was obviously lowered in rats with TobraDex treatment. Immunohistochemical examination revealed that the expression of SDF-1 and CXCR4, found mainly in the corneal epithelium and stroma, was significantly increased in the allografts in rats with saline treatment. CONCLUSION: SDF-1/CXCR4 may participate in corneal graft rejection in rats early after transplantation possibly through the mechanism that SDF-1 specifically induces CXCR4+ cell maturation and chemotaxis toward the allograft to promote corneal neovascularization.

Increased expression of Lgr5 is associated with chemotherapy resistance in human gastric cancer.

Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5), a marker of adult stem cells and cancer stem cells, plays important roles in tumor progression. Furthermore, Lgr5 also contributes to chemoradiotherapy resistance. However, the function of Lgr5 in the prediction of preoperative chemotherapy efficacy has not been reported. We evaluated the potential of Lgr5 in predicting tumor response and overall survival in advanced gastric cancer treated with preoperative chemotherapy. The association between Lgr5 and chemotherapy resistance was also investigated in gastric cancer cell lines. Hematoxylin and eosin staining and immunohistochemical analysis of Lgr5 expression were performed in 68 cases of gastric cancer treated with preoperative chemotherapy. Lgr5 expression was specifically silenced in the AGS gastric cancer cell lines by RNA interference. Levels of Lgr5 mRNA and protein in cell lines were detected by quantitative reverse transcription-polymerase chain reaction or western blotting. Cell viability was evaluated by an MTT assay. Cell apoptosis was assessed by Annexin V-FITC/propidium iodide dual staining analysis. We found that Lgr5 expression was significantly associated with tumor regression grade after preoperative chemotherapy. The rate of positive Lgr5 expression was significantly higher in patients with poor tumor regression compared with those exhibiting tumor regression (P=0.001). Lgr5-positive patients had a significantly shorter survival time than Lgr5-negative patients (P=0.001). Inhibition of Lgr5 expression with small interfering RNA increased the sensitivity of AGS gastric cancer cells to chemotherapy. Our findings suggest that Lgr5 expression may be implicated in the chemoresistance of gastric cancer cells and is a potential novel biomarker for predicting response to chemotherapy and prognosis in gastric cancer patients, and may also represent a potential new therapeutic target for cancer therapy.

High-mobility Bi2Se3 nanoplates manifesting quantum oscillations of surface states in the sidewalls.

Magnetotransport measurements of topological insulators are very important to reveal the exotic topological surface states for spintronic applications. However, the novel properties related to the surface Dirac fermions are usually accompanied by a large linear magnetoresistance under perpendicular magnetic field, which makes the identification of the surface states obscure. Here, we report prominent Shubnikov-de Haas (SdH) oscillations under an in-plane magnetic field, which are identified to originate from the surface states in the sidewalls of topological insulator Bi2Se3 nanoplates. Importantly, the SdH oscillations appear with a dramatically weakened magnetoresistance background, offering an easy path to probe the surface states directly when the coexistence of surface states and bulk conduction is inevitable. Moreover, under a perpendicular magnetic field, the oscillations in Hall conductivity have peak-to-valley amplitudes of 2 e(2)/h, giving confidence to achieve a quantum Hall effect in this system. A cross-section view of the nanoplate shows that the sidewall is (015) facet dominant and therefore forms a 58° angle with regard to the top/bottom surface instead of being perpendicular; this gives credit to the surface states' behavior as two-dimensional transport.

Improvement of ultraviolet photoresponse of bent ZnO microwires by coupling piezoelectric and surface oxygen adsorption/desorption effects.

Localized ultraviolet photoresponse properties of bent ZnO microwires bridging two perfect Ohmic contacts in both atmospheric and high vacuum (8 × 10(-6) torr) environments have been investigated for the first time to explore the bending strain effect on the photoelectrical properties of ZnO. It is found that the ZnO microwire has higher photoconductivity and faster rising speed when photo-excitation is localized at the bending region in an atmospheric environment, while the rising speeds are almost the same when photo-excitations are localized at the bending and straight regions under vacuum. The bending strain induced improvement of the UV photoresponse in air was well explained by considering the coupling of piezoelectric effects and the surface oxygen adsorption/desorption procedure on the bent ZnO microwire. Our results are valuable for designing and fabricating strain modulated photoelectrical micro/nano-devices.

Synthesis and quantum transport properties of Bi2Se3 topological insulator nanostructures.

Bi2Se3 nanocrystals with various morphologies, including nanotower, nanoplate, nanoflake, nanobeam and nanowire, have been synthesized. Well-distinguished Shubnikov-de Haas (SdH) oscillations were observed in Bi2Se3 nanoplates and nanobeams. Careful analysis of the SdH oscillations suggests the existence of Berry's phase π, which confirms the quantum transport of the surface Dirac fermions in both Bi2Se3 nanoplates and nanobeams without intended doping. The observation of the singular quantum transport of the topological surface states implies that the high-quality Bi2Se3 nanostructures have superiorities for investigating the novel physical properties and developing the potential applications.

Aberrant expression of EphA3 in gastric carcinoma: correlation with tumor angiogenesis and survival.

BACKGROUND: EphA3, a member of the Eph receptor tyrosine kinases, plays important roles in tumor angiogenesis and progression. However, the function of EphA3 in solid tumors has not been widely studied. We aimed to explore EphA3 expression in gastric carcinoma and analyze its role as a potential prognostic factor. METHODS: Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess EphA3 mRNA in a normal gastric mucosa cell line and carcinoma cell lines. Immunohistochemistry for EphA3 and vascular endothelial growth factor (VEGF) was performed in 318 cases of gastric carcinoma. CD34 immunohistochemical staining was used for microvessel density (MVD) counting. Western blotting was used to analyze EphA3 expression in the cell lines and to determine the expression of EphA3 and VEGF in 75 cases of gastric carcinoma and matched normal mucosa. RESULTS: EphA3 mRNA and protein expression was significantly higher in gastric cancer than that in normal mucosa (all P < 0.001). EphA3 was significantly correlated with TNM stage and poor prognosis (all P < 0.001). Multivariate analysis showed that EphA3 had an independent effect on survival (P = 0.037). EphA3 was positively correlated with VEGF (P < 0.001), and MVD (P < 0.001). According to Western blot analysis, both EphA3 and VEGF expression were significantly higher in carcinoma than that in normal mucosa (all P < 0.001). A positive correlation was observed between EphA3 and VEGF expression in cancer (P < 0.001, r = 0.513). CONCLUSIONS: EphA3 may play important roles in the angiogenesis and prognosis of gastric carcinoma, and thus may become a useful target for therapeutic intervention and a potential indicator for clinical assessment of tumor prognosis.