Production of azimuthally polarized beam with helical phase by use of the axicons and annular glass cylinder.

In this paper, we proposed a method for producing the azimuthally polarized vector beam experimentally. The experimental setup includes two of the same axicons and one annular glass cylinder. The top angles of the two axicons were placed facing each other and the annular cylinder was set among the two axicons. One circular polarized beam was passed through the first axicon, the annular cylinder, and the second axicon in turn. When the beam incident on the inner surface of the annular cylindrical satisfied the Brewster angle, we obtained the azimuthally polarized beam for the reflected light from the annular cylindrical that only contains the $s$s-polarization component. We have derived that the azimuthally polarized vector beam has the helical phase factor with the helical phase factor of ${\exp}( - {\rm i}\varphi )$exp(-iφ) for the left circularly polarized beam incident and ${\exp}({\rm i}\varphi )$exp(iφ) for the right circularly polarized beam incident.

Generation of propagation-invariant vector beams with square array by use of 2D binary phase mask and pentagonal prism.

In this paper, we realize the generation of propagation-invariant vector beams with square array by use of a 2D binary phase mask and pentagonal prism in a typical Mach-Zehnder optical system. The binary phase mask set in the optical system is perpendicular to the optical axis, and its periodic orientation is 45° relative to the horizontal and vertical directions. One polarizer was used to produce the linearly polarized beam with the angle of 45° relative to the horizontal and vertical directions. One mirror in the Mach-Zehnder optical system was replaced by a pentagonal prism, as the light will be reflected twice inside the pentagonal prism. The intensity distribution of the two branches with the mirror and pentagonal prism have mirror symmetry, and the output optical field of the two branches has an orthogonal polarization state. By adjusting the position of the phase plate accordingly, the total optical field of the two branches can form a vector beam with a square array. The experimental results coincide with the simulation results very well and demonstrate the feasibility of this method.

Generation of arbitrary vector beams with cascaded liquid crystal spatial light modulators.

A flexible approach is presented to generate vector beams with arbitrary polarization and complex amplitude by means of two cascaded transmissive liquid crystal spatial light modulators (LCSLMs). The configuration of the cascaded LCSLM system and its modulation characteristic are introduced. Theoretical analysis and experimental demonstration prove that the system in combination with a double-pass computer-generated hologram and a black-and-white pattern can generate vector beams with arbitrary polarization and complex amplitude by respectively controlling the complex amplitudes of two orthogonal polarization components of the beams. Using this system, we successfully generate radially polarized vector beams with helical phase distributions and vector Bessel beams with inhomogeneous amplitude distributions in experiments.

Radial Hilbert transform with the spatially variable half-wave plate.

We analyzed the point spread function (PSF) of the typical 4f optical image processing system by use of a spatially variable half-wave plate as the spatial filter and found that the PSF is an elementary vector beam. Theoretical analysis and real experiments show that the optical system can be used for a radially symmetric Hilbert transform that permits two-dimensional edge enhancement as the spiral phase plate. This kind of radial Hilbert transform is useful for image processing because it can enhance the edges of an input image selectively by exerting a polarization analyzer before the output plane. The optical system also can be used for generation of vector beams with arbitrary array and shape in real time conveniently.

Preoperative Cyfra21-1 and SCC-Ag serum titers predict survival in patients with stage II esophageal squamous cell carcinoma.

BACKGROUND: The purpose of this study is to evaluate the predictive significance of preoperative serum level of cytokeratin 19 fragments (Cyfra21-1) and squamous cell carcinoma antigen (SCC-Ag) after complete resection in patients with stage II esophageal squamous cell carcinoma (ESCC). METHODS: Between 1995 and 2006, a total of 379 patients in stage II ESCC who underwent complete resection were consecutively recruited. Statistical analyses were applied to test the associations between preoperative serum titers of Cyfra21-1 and SCC-Ag, clinicopathological factors and prognoses. RESULTS: Preoperative high and normal serum level of Cyfra21-1 and SCC-Ag were found in 47.8%, 52.2% and 72.8%, 27.2%, respectively. The 1-, 3-, 5-year overall survival rate for the entire cohort of patients was 95%, 78%, and 56%, respectively. Median overall survival (OS) was 45.3 months longer in patients with low preoperative serum level of Cyfra21-1 (91.9 months) than those with high preoperative serum level of Cyfra21-1 (46.6 months) (P < 0.001). Median OS among patients with SCC-Ag-low level was also longer than those with SCC-Ag-high level (89.7 vs. 63.7 months, P < 0.001), especially for those with stage IIB (P < 0.001). After multivariate analysis, along with pTNM stage, preoperative serum level of Cyfra21-1 and SCC-Ag were independently and significantly predictive factors (P < 0.001, P < 0.001). Furthermore, the five-year survival rate in double-low subset, either-low subset and double-high subset was 100%, 83% and 27%, respectively (P < 0.001). CONCLUSIONS: The preoperative serum level of Cyfra21-1 and SCC-Ag are independently significant predictors which negatively affected the survivals of patients with stage II ESCC.

[Rule of acupoint combination in acupuncture treatment of hiccup: a study based on complex network analysis].

OBJECTIVE: To explore the rule of acupoint combination in acupuncture treatment of hiccups. METHODS: Original research articles on acupuncture treatment of hiccup were collected from databases of CNKI, Wanfang, VIP, and Pubmed by using key words of "hiccup", "acupuncture" "diaphragmatic spasm" "body acupuncture" "filiform needle" and "electroacupuncture". According to our inclusive and exclusive criteria, the collected data were extracted to establish an acupuncture prescription database for hiccup. Then, the regularities of acupoint combinations for hiccup were analyzed by using Gephi complex network analysis software. RESULTS: ;A total of 606 articles containing 634 acupoint prescriptions for acupuncture treatment of hiccups were brought into analysis. There were 133 single-acupoint prescriptions (20.98%), which was significantly lower than the multi-acupoint prescription (501, accounting for 79.02%). There were mainly acupoints in multi-acupoint prescriptions, and distal-proximal acupoint combination method were often used as the basis of acupoint selection (326, accounting for 65.07%). A total of 163 acupoints were involved, with a total frequency of 2 969. Among them, Neiguan(PC6) was used most frequently (400 times, accounting for 13.47%), followed by Zusanli (ST36), Zhongwan (CV12), Danzhong (CV17), and Taichong (LR3). The acupoints of the Conceptional Vessel(666 times, accounting for 22.43%), and Stomach Meridian, Pericardium Meridian and Liver Meridian were chiefly used. There were 67 specific acupoints, the frequency of use was 2 555 times(accounting for 86.05% of the total frequency), among which the frequency of the five Shu-points was the highest (875 times, accounting for 29.47% of the total frequency), and followed by eight confluence points. CONCLUSION: ;The core acupoints are PC6, ST36, CV12, etc. and the distal-proximal acupoint combination method found in this study are often used as the basis of acupoint selection and acupoint prescription for acupuncture treatment of hiccup.

Establishment and characterization of a new cell line derived from human colorectal laterally spreading tumor.

AIM: To study the molecular mechanism of laterally spreading tumor (LST), a cell line [Laterally Spreading Tumor-Rectum 1 (LST-R1)] was derived and the characteristics of this cell line were investigated. METHODS: A new cell line (LST-R1) originated from laterally spreading tumor was established. Properties of the cell line were characterized using scanning and transmission electron microscopy, immunohistochemistry method, cytogenetic analysis and nude mice xenograft experiments. In vitro invasion assay, cDNA microarray and Western blotting were used to compare the difference between the LST-R1 and other colorectal cancer cell lines derived from prudent colon cancer. RESULTS: Our study demonstrated that both epithelial special antigen (ESA) and cytokeratin-20 (CK20) were expressed in LST-R1. The cells presented microvilli and tight junction with large nuclei. The karyotypic analysis showed hyperdiploid features with structural chromosome aberrations. The in vivo tumorigenicity was also demonstrated in nude mice xenograft experiments. The invasion assay suggested this cell line has a higher invasive ability. cDNA microarray and Western blotting show the loss of the expression of E-cadherin in LST-R1 cells. CONCLUSION: We established and characterized a colorectal cancer cell line, LST-R1 and LST-R1 has an obvious malignant tendency, which maybe partially attributed to the changes of the expression of some adhesion molecules, such as E-cadherin. It is also a versatile tool for exploring the original and progressive mechanisms of laterally spreading tumor and the early colon cancer genesis.

Tyrosine-protein phosphatase non-receptor type 12 expression is a good prognostic factor in resectable non-small cell lung cancer.

Tyrosine-protein phosphatase non-receptor type 12 (PTPN12) has been considered to be a tumor suppressor in human cancer, but its clinical and prognostic significance in non-small cell lung cancer (NSCLC) has not been well elucidated.A retrospective analysis of 215 patients with surgically resected NSCLCs from Sun Yat-Sen University Cancer Center between April 2002 and March 2005 was performed using immunohistochemistry and Western Blot to analyze PTPN12 expression. The association between PTPN12 expression and patient survival was investigated.Western Blots showed that the expression level of PTPN12 were higher in normal paracancerous lung tissues than in NSCLC tissues. High PTPN12 expression was less common in the presence than in the absence of visceral pleural invasion (p=0.038). Patients with PTPN12-high tumors had a longer disease-free survival (DFS) (P<0.001) and overall survival (OS) (p<0.001), especially for those with non-squamous cell carcinoma (non-SCC) (DFS, p<0.001; OS, p<0.001). Multivariate analysis confirmed that PTPN12 positivity was associated with increased survival duration (DFS, p<0.001; OS, p<0.001), independent of prognostic indicator.High PTPN12 expressive levels are associated with favorable survival duration in patients with NSCLC, especially those with non-SCC. Our study suggests that PTPN12 expression is a valuable prognostic biomarker for NSCLC patients.

Expression of Cystatin SN significantly correlates with recurrence, metastasis, and survival duration in surgically resected non-small cell lung cancer patients.

Cystatin SN has been considered to be involved in human cancer, but its clinical significance in non-small cell lung cancer (NSCLC) has not been elucidated. The aim of this study was to evaluate the clinical value of Cystatin SN expression in patients with surgically resected NSCLCs. A retrospective analysis of 174 patients with surgically resected NSCLCs from April 2002 to March 2005 was performed with immunohistochemistry and fluorescence in situ hybridization to analyze the protein expression and amplification of Cystatin SN. The associations between Cystatin SN expression and recurrence, metastasis, and survival were investigated. In recurrence and metastasis analysis, compared with low-Cystatin SN expression NSCLCs, high expression tumors were more likely to recur and metastasize (P < 0.001). Disease-free survival (DFS) and overall survival (OS) were significantly prolonged in the low-Cystatin SN expression subgroup compared with the high-Cystatin SN expression subgroup (DFS, P < 0.001; OS, P = 0.001). A multivariate analysis confirmed that high expression of Cystatin SN was associated with poor survival (DFS, P = 0.001; OS, P = 0.006) and was an independent prognostic indicator. The present study indicates that high expression of Cystatin SN is a significant prognostic indicator of a higher rate of recurrence, metastatic risk, and poor survival in patients with surgically resected NSCLCs.

Quasi-steady-state air plasma channel produced by a femtosecond laser pulse sequence.

A long air plasma channel can be formed by filamentation of intense femtosecond laser pulses. However, the lifetime of the plasma channel produced by a single femtosecond laser pulse is too short (only a few nanoseconds) for many potential applications based on the conductivity of the plasma channel. Therefore, prolonging the lifetime of the plasma channel is one of the key challenges in the research of femtosecond laser filamentation. In this study, a unique femtosecond laser source was developed to produce a high-quality femtosecond laser pulse sequence with an interval of 2.9 ns and a uniformly distributed single-pulse energy. The metre scale quasi-steady-state plasma channel with a 60-80 ns lifetime was formed by such pulse sequences in air. The simulation study for filamentation of dual femtosecond pulses indicated that the plasma channel left by the previous pulse was weakly affected the filamentation of the next pulse in sequence under our experimental conditions.

[Pit pattern and endoscopic mucosal resection in diagnosis and treatment of colorectal tumors].

OBJECTIVE: To explore the effective methods to diagnose and treat colorectal cancer in its early stage. METHODS: 1 205 patients were examined by colonoscopy and mucosa staining with indigocarmine. The pit patterns were observed with magnifying endoscope and stereomicroscope according to the Kudo classification. The pathological diagnoses of the lesions were compared with their pit patterns. Electrocoagulation resection was performed on the prominent lesions and endoscopic mucosal resection (EMR) or endoscopic partial mucosal resection (EPMR) was performed on the flat lesions. RESULTS: In the 282 patients 478 prominent and flat lesions were found. There were 16 cases of laterally spreading tumor (LST), including I case of pit pattern II, 6 of pit pattern IIIL, 8 of pit pattern IV, and 1 of pit pattern Va, with 2 cases of intramembrane cancer and 1 case of IIa + IIc lesions invading the superficial myometrium among them. EMR and EPMR were performed on 14 LST lesions, 22 IIa lesions, and 14 IIb lesions. CONCLUSION: The examination of pit pattern is very important in early diagnosis of colorectal cancer and differentiation tumorous from non-tumorous lesions. V type pit pattern is an indicator of colorectal cancer. EMR and EPMR are safe and effective for flat lesions.

[Magnifying endoscope and stereomicroscope in diagnosing colon tumor: experience with 139 cases].

OBJECTIVE: To explore the practical means for identifying early large bowel carcinoma and precancerous lesions with magnifying endoscope. METHODS: We examined 139 patients with polyp using colonoscopy and mucosal staining, and observed the pit patterns (proposed by Kudo) with magnifying endoscope and stereomicroscope to identify the relations between the pit patterns and the pathologic diagnosis. RESULTS: Polyps were identified in 124 patients and advanced cancers in 9. Five laterally spreading tumors (LST) ranging from 10 to 50 mm in diameter, including 1 of pit IIIL, and 4 of pit IV. were found. The findings of the pit patterns by magnifying endoscope were highly consistent with those by stereomicroscope in these patients. CONCLUSIONS: Pit patterns are crucial to distinguish the cancerous lesions form non-cancerous one and helpful for early detection of colorectal cancers. Pit V may serve as warning sign of early cancerous lesions.

[Electron microscopic observation of primary cultured laterally spreading tumor cell line].

OBJECTIVE: To observe the microscopic characteristics of laterally spreading tumor (LST) cell line in primary culture. METHODS: The cells isolated from a rectum LST specimen obtained by endoscopic mucosal resection was primary cultured, followed by observation with scanning and transmission electron microscope in comparison with the cells of adenocarcinoma and normal mucosa of the rectum. RESULTS: Scanning and transmission electron microscopes both revealed numerous microvilli covering the surface of the LST cells, and the cytoplasm contained large quantity of lysosomes, mitochondria and phagosomes. Obviously heterogeneous cell nuclei were present with abnormal nuclear fossa and huge nucleoli. CONCLUSION: The cultured LST cells are highly malignant.

Overexpression of hTERT in potentially malignant colorectal laterally spreading tumors.

Human telomerase reverse transcriptase (hTERT) is the main subunit of the core enzyme telomerase, which consists of three subunits. Telomeres are essential for chromosomal stability and integrity, protecting the ends of chromosomes from degradation and preventing chromosomal end fusions and recombination. A loss of telomere function is a major mechanism for the generation of chromosomal abnormalities. Telomere shortening leads to mutations, chromosome rearrangements and translocations. Colorectal laterally spreading tumors (LSTs) are a special type of superficial colorectal tumor. They are considered to have a high malignancy potential. The aim of the present study was to characterize the expression of hTERT in an LST cell line and paraffin sections. Immunohistochemistry was utilized to examine the protein expression of hTERT in the LST cell line, 48 resected LSTs, 48 protruded-type colorectal adenomas (PAs) and 48 normal mucosa samples. Statistical analyses were applied to test the associations between hTERT expression and clinicopathological parameters. The present study demonstrated that the positive expression levels of hTERT in LSTs, PAs and normal mucosa were 60.4, 22.9 and 10%, respectively. Compared with polypi and normal mucosa, the expression levels of hTERT were significantly increased in LSTs. The expression of hTERT was also observed in the LST cell line. The expression of hTERT was significantly higher in LSTs, which may indicate a potential for malignancy.

[Expression of PAK4 in breast cancer and benign breast pathological changes].

OBJECTIVE: To study the role of p21-activated kinase-4 (PAK4) in the occurrence, progression and metastasis of breast cancer. METHOD: PAK4 expression was detected in 35 cases of normal breast, 22 breast cystic hyperplasia, 28 breast adenofibroma, 37 breast cancer (including 7 non-invasive cancer, 9 early invasive cancer and 21 invasive cancer) and 13 metastatic breast cancer tissues using immunohistochemistry for a comparison of PAK4 expression and distribution. RESULTS: PAK4 was expressed mainly in the cytoplasm of the cancer cells, occasionally in the cell nuclei, and virtually not expressed in the matrix surrounding the breast cells. PAK4 positivity rates increased in the order of normal breast tissues, benign changes (including breast cystic hyperplasea and breast adenoma), breast cancer and metastatic cancer tissues; in the cancer tissues, the positivity rates increased in the order of non-invasive breast tumor, early invasive tumor and invasive tumor tissues. CONCLUSION: PAK4 is closely correlated to the progression and metastasis of breast cancer and may become a new diagnostic and therapeutic target of breast cancer.

[Effect of p21-activated kinase-1 on the invasiveness of colorectal carcinoma cells in vitro].

OBJECTIVE: To observe the effect of p21-activated kinase-1 (PAK1) gene transfection on the invasiveness of human colorectal carcinoma SW480 cells in vitro. METHODS: SW480 cells in routine culture were transfected with the recombinant plasmid EGFP-C1/PAK1 via Lipofectamine(TM) 2000. The expression of PAK1 protein in SW480 cells was detected using Western blotting, and the changes of the invasiveness of SW480 cells were evaluated using Boyden chamber invasion assay. RESULTS: Forty-eight hours after transfection with pEGFP-C1/ PAK1, the PAK1 protein expression increased significantly in comparison with those in negative and vector control groups. The invasiveness of the SW480 cells was significantly enhanced after the transfection. CONCLUSION: The PAK1 gene transfection can increase the expression of PAK1 in SW480 cells and enhance the invasiveness of the cells. PAK1 can be associated with the invasiveness and metastasis of colorectal carcinoma cells.

[Cloning of human PAK6 cDNA, preparation of anti-PAK6 polyclonal antibody and PAK6 expression in prostate cancer].

OBJECTIVE: To study the role of PAK6 in prostate cancer by cloning PAK6-N terminal sequence into E.coli and preparing its polyclonal rabbit antibody to detect PAK6 expression in prostate cancer. METHODS: Based on human PAK6 cDNA sequence, we designed a pair of primers to amplify the PAK6-N terminal sequence by PCR. The PCR product was subcloned into the bacterial expression vector pGEX-4T-1 via EcoRI/XhoI sites, and the recombinant plasmids were identified by enzymatic cleavage followed by DNA sequence analysis. By transforming the expression vector into component E.coli BL21 cells, the GST-PAK6-N fusion protein was expressed with IPTG induction. Glutathione-Sepharose beads were used to purify GST- PAK6-N fusion protein. Anti-PAK6 polyclonal antibody was produced by immunizing rabbits with purified GST-PAK6 N-terminal fusion protein. Anti-PAK6 polyclonal antibody was purified by protein A beads and used for detection of PAK6 expression in 3 prostate cancer specimens. RESULTS AND CONCLUSION: We cloned PAK6-N terminal gene fragment successfully, purified GST-PAK6 N-terminal fusion protein, and obtained polyclonal rabbit PAK6 antibody. Immunohistochemistry indicated that PAK6 expressed in the stroma instead of the cancer cells in prostate cancer. All of the 3 prostate cancer specimens showed positive staining in the stroma, suggesting that PAK6 may participate in the stroma-cancer cell interaction in prostate cancer.

Radial Hilbert transform with Laguerre-Gaussian spatial filters.

We analyze the point spread function (PSF) of the image processing system for radial Hilbert transform and propose a novel spiral phase filter, called the Laguerre-Gaussian spatial filter (LGSF). Theoretical analysis and real experiments show that the LGSF possesses some advantages in comparison with the conventional spiral phase plate (SPP). For example, the PSF of the imaging system with a LGSF presents smaller suboscillations than that with the conventional SPP, which allows us to realize a radial Hilbert transform for achieving a high contrast edge enhancement with high resolution.

[Expression and significance of ADP-ribosylation factor 1 (ARF1) in colorectal laterally spreading tumor].

BACKGROUND & OBJECTIVE: Laterally spreading tumor (LST) behaves close to malignant tumor. This study was to search for the genes and functional proteins correlated to growth and development of colorectal LST (CLST), and to reveal the molecular mechanisms of CLST growth pattern and malignant transformation. METHODS: cDNA microarray was used to screen differentially expressed genes among CLST cell line and other 2 colorectal cell lines LoVo and SW480. Different mRNA and protein expressions of the genes were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: Compared with LoVo and SW480 cells, 58 genes were up-regulated and 39 genes were down-regulated in CLST cells. mRNA level of ADP-ribosylation factor 1 (ARF1) was significantly higher in CLST cells than in SW480 and LoVo cells (0.93 vs. 0.74 and 0.47, P = 0.04); protein level of ARF1 was significantly higher in CLST cells than in LoVo cells. CONCLUSIONS: CLST has specific gene expression profile. ARF1 is overexpressed in CLST, and may mediate specific biological function of CLST.