Highly boosted trace-amount terahertz vibrational absorption spectroscopy based on defect one-dimensional photonic crystal.

Although terahertz (THz) spectroscopy demonstrates great application prospects in the fields of fingerprint sensing and detection, traditional sensing schemes face unavoidable limitations in the analysis of trace-amount samples. In this Letter, a novel, to the best of our knowledge, absorption spectroscopy enhancement strategy based on a defect one-dimensional photonic crystal (1D-PC) structure is proposed to achieve strong wideband terahertz wave-matter interactions for trace-amount samples. Based on the Fabry-Pérot resonance effect, the local electric field in a thin-film sample can be boosted by changing the length of the photonic crystal defect cavity, so that the wideband signal of the sample fingerprint can be greatly enhanced. This method exhibits a great absorption enhancement factor, of about 55 times, in a wide terahertz frequency range, facilitating the identification of different samples, such as thin α-lactose films. The investigation reported in this Letter provides a new research idea for enhancing the wide terahertz absorption spectroscopy of trace samples.

Enhanced trace-amount terahertz vibrational absorption spectroscopy using surface spoof polarization in metasurface structures.

Terahertz (THz) absorption spectroscopy is a powerful tool for molecular label-free fingerprinting, but it faces a formidable hurdle in enhancing the broadband spectral signals in trace-amount analysis. In this paper, we propose a sensing method based on the geometry scanning of metal metasurfaces with spoof surface polarization sharp resonances by numerical simulation. This scheme shows a significant absorption enhancement factor of about 200 times in an ultra-wide terahertz band to enable the explicit identification of various analytes, such as a trace-amount thin lactose film samples. The proposed method provides a new, to the best of our knowledge, choice for the enhancement of wide terahertz absorption spectra, and paves the way for the detection of trace-amount chemical, organic, or biomedical materials in the terahertz regime.

One-dimensional terahertz dielectric gradient metasurface for broadband spoof surface plasmon polaritons couplers.

At present, most of the gradient metasurfaces used to construct surface plasmon polaritons (SPPs)/spoof SPPs (SSPs) couplers are usually compact metal antennas working under reflection and transmission. In reflection mode, meta-couplers link propagating waves and surface waves (SWs), and SWs will undergo significant scattering before coupling to an Eigen SPP in the target system. In transmission mode, metal meta-couplers will encounter complex multilayer designing at the microwave/terahertz region and metal absorption loss at optical frequencies. In this Letter, to the best of our knowledge, a novel design using dielectric gradient metasurfaces instead of metal metasurface couplers is proposed to excite broadband SSPs on the metal groove array. We demonstrate that the well-designed phase dielectric gradient metasurface converts the normal incident terahertz wave to the predetermined angle in the dielectric substrate and then excites the broadband SSPs with the transmission coupling between the dielectric meta-coupler and SSPs surface. This research may open up new avenues in simple and broadband plane dielectric meta-couplers for SSPs in ultra-thin and compact functional devices for versatile applications.

One-dimensional terahertz dielectric gradient metasurface for broadband spoof surface plasmon polaritons couplers: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 290 (2021)OPLEDP0146-959210.1364/OL.412229.

Decoding spectro-temporal representation for motor imagery recognition using ECoG-based brain-computer interfaces.

One of the challenges in brain-computer interface systems is obtaining motor imagery recognition from brain activities. Brain-signal decoding robustness and system performance improvement during the motor imagery process are two of the essential issues in brain-computer interface research. In conventional approaches, ineffective decoding of features and high complexity of algorithms often lead to unsatisfactory performance. A novel method for the recognition of motor imagery tasks is developed based on employing a modified S-transforms for spectro-temporal representation to characterize the behavior of electrocorticogram activities. A classifier is trained by using a support vector machine, and an optimized wrapper approach is applied to guide selection to implement the representation selection obtained. A channel selection algorithm optimizes the wrapper approach by adding a cross-validation step, which effectively improves the classification performance. The modified S-transform can accurately capture event-related desynchronization/event-related synchronization phenomena and can effectively locate sensorimotor rhythm information. The optimized wrapper approach used in this scheme can effectively reduce the feature dimension and improve algorithm efficiency. The method is evaluated on a public electrocorticogram dataset with a recognition accuracy of 98% and an information transfer rate of 0.8586 bit/trial. To verify the effect of the channel selection, both electrocorticogram and electroencephalogram data are experimentally analyzed. Furthermore, the computational efficiency of this scheme demonstrates its potential for online brain-computer interface systems in future cognitive tasks.

Effect of interleukin-1ß and lipoxin A4 in human endometriotic stromal cells: Proteomic analysis.

AIM: Lipoxin A4 (LXA4 ) can function as an endogenous 'breaking signal' in inflammation and plays an important role in the progression of endometriosis. The proteome responses to interleukin-1ß (IL-1ß) or LXA4 in human endometriotic stromal cells (ESC) are not well understood. METHODS: In this study, primary ESC were cultured from ovarian endometriosis tissue. Three groups were established: the control group; the IL-1ß stimulation group; and the IL-1ß and LXA4 incubation group. Proteins were assessed on 2-D polyacrylamide gel electrophoresis (2D-PAGE), and differentially expressed protein spots were further identified on matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MALDI-TOF-MS). Wound healing and transwell assays were performed to assess the migration and invasion of ESC after treatment. RESULTS: In total, 40 differentially expressed protein spots were identified successfully on MALDI-TOF-MS. The proteins identified were related to cell structure, metabolism, signal transduction, protein synthesis and membrane structure, processes that may be involved in the development of endometriosis. Vinculin and IL-4 were further analyzed on western blot and quantitative real-time polymerase chain reaction. Moreover, LXA4 could suppress the migration and invasion of ESC induced by IL-1ß. CONCLUSION: LXA4 may inhibit the progression of endometriosis partly by lowering or raising the effect of IL-1ß, mediated via some inflammation-related proteins (e.g. vinculin) and immune response-related protein (e.g. IL-4) in vitro.

[Near infrared Cavity enhanced absorption spectroscopy study of NO2O].

Using a tunable near infrared external cavity diode laser and a 650 mm long high finesse optical cavity consisting of two highly reflective (R=99.97% at 6561.39 cm(-1)) plan-concave mirrors of curvature radius approximately 1000 mm, a cavity enhanced absorption spectroscopy (CEAS) system was made. The absorption spectra centered at 6561.39 cm(-1) of pure N2O gas and gas mixtures of N2O and N2 were recorded. According to the absorption of N2O at 6561.39 cm(-1) in the cavity, the measured effective absorption path was about 1460 km. The spectra line intensity and line-width of N2O centered at 6561.39 cm(-1) were carefully studied. The relationship between the line-width of absorption spectra and the gas pressure was derived. The pressure broadening parameter of N2 gas for NO2O line centered at 6 561. 39 cm(-1) was deduced and given a value of approximately (0.114 +/- 0.004) cm(-1) x atm(-1). The possibility to detect trace N2O gas in mixture using this CEAS system was investigated. By recording the ab- sorption spectra of N2O gas mixtures at different concentration, the relationship between the line intensity and gas concentration was derived. The minimum detectable absorption was found to be 2.34 x 10(-7) cm(-1) using this cavity enhanced absorption spectroscopy system. And te measurement precision in terms of relative standard deviation (RSD) for N2O is approximately 1.73%, indicating the possibility of using the cavity enhanced absorption spectroscopy system for micro gas N2O analysis in the future.

[Determination of trace Cu in water by laser-induced breakdown spectroscopy].

In the present article, the ordinary printing paper was immerged in the aqueous solution of CuCl2, and used as an absorber for the enrichment of heavy metal copper in liquid. After being taken from the solution and dried, the paper was then analyzed using laser-induced breakdown spectroscopy. This method overcomes the drawbacks of splashing and low sensitivity in the process of direct analysis of heavy metal in water sample with LIBS. The Cu 324.7 nm spectral line was used as the analysis line in experiment. The variation in the line intensity at different enrichment time was studied. The calibration curve for the quantitative measurement of Cu in water was established, the detection limit was 0.023 mg x L(-1), which is about three orders of magnitude improvement compared with that in ordinary LIBS analysis of heavy metal in solution. It is likely that this technique will be practically helpful in the sensitive analysis of the heavy metal in water.

[Laser ablation and fast pulse discharge plasma spectroscopy analysis of Sn in soil].

A developing technique, laser ablation and fast pulse discharge plasma spectroscopy technique (LA-FPDPS), was used for the first time to analyze the Sn concentration in soil. The peak intensity of Sn (284.0 nm) line from soil plasma emission was greatly enhanced in comparison with using the traditional single pulse (SP) LIBS system. Using the technique, calibration curve of Sn in soil was derived. The limit of detection (LOD) for Sn in soil was reduced to be 0.16 microg x g(-1). The value is significantly improved compared with the results reported in literature when using LIBS technique, which usually was between 8.2 to 54 microg x g(-1) depending on the experimental condition, indicating that this technique possibly will be useful for rapid quantitative elemental analysis in soil.

[Effects of Hematocrit on the Parameters of Thromboelastography in Healthy Adults].

OBJECTIVE: To explore the effects of hematocrit (HCT) on the parameters of thromboelastography (TEG) in healthy adults, so as to judge coagulation and fibrinolysis more accurately. METHODS: Three hundred and ninety-three healthy adults examined in Chengdu 363 Hospital Affiliated to Southwest Medical University from May 2018 to May 2019 were selected. HCT and TEG were detected at the same time. The differences of TEG parameters between the high HCT group and the low HCT group were compared. The correlation between HCT and TEG parameters was analyzed. The differences of TEG parameters between the healthy adults in Plateau and plain areas were compared. RESULTS: Among the parameters of TEG, R and K in high HCT group were significantly higher, and Angle, MA and CI were significantly lower than those in low HCT group, which showed statistically significance (P<0.05). There was no significant difference in LY30 and EPL between the two groups (P>0.05). R and K positively correlated with HCT (r=0.112, 0.517, P=0.027, 0.000), and Angle, MA and CI negatively correlated with HCT (r=-0.490, -0.408, -0.414, P=0.000). LY30 and EPL not correlated with HCT (P>0.05). HCT in plateau area was significantly higher than that in plain area (P<0.05). Among the parameters of TEG, K value was significantly higher, and Angle, MA and CI were significantly lower than those in plain area (P<0.05). R, LY30 and EPL were not significantly different from those in plain area (P>0.05). CONCLUSION: The difference of HCT may affect the values of R, K, Angle, MA and CI in TEG parameters. R and K positively correlate with HCT, while Angle, MA and CI negatively correlate with HCT. It is suggested that a suitable TEG reference range for the local population should be established, in plateau area especially K, Angle, MA and CI, which will be more conducive to the accurate evaluation of patients' coagulation and fibrinolysis status.

Enzalutamide-Induced Upregulation of PCAT6 Promotes Prostate Cancer Neuroendocrine Differentiation by Regulating miR-326/HNRNPA2B1 Axis.

Our previous studies have demonstrated that Enzalutamide-induced upregulation of long non-coding RNA p21 (lncRNA-p21) facilitates prostate cancer (PCa) neuroendocrine differentiation (NED). Given the important role of lncRNAs in PCa pathogenesis, and given that lots of lncRNAs are dys-regulated in neuroendocrine PCa (NEPC) patients, we next explored the biological function and underlying mechanism of lncRNA-PCAT6 (PCAT6) in mediating Enzalutamide-induced NED. The level of PCAT6 in Enzalutamide-treated PCa cells and NEPC samples were assessed using quantitative RT-PCR (qPCR). The effect of PCAT6 on PCa cell proliferation, invasion, and NED was evaluated through CCK-8, transwell, qPCR, western blot analysis, Xenograft mouse model, and in vivo lung metastasis model. We found that PCAT6 was highly expressed in NE-like cells (PC3, DU145, and NCI-H660) compared with androgen-sensitive LNCaP cells. PCAT6 was also highly expressed in NEPC tissues. Enzalutamide treatment resulted in a significant increase of PCAT6 level in a dose- and time-dependent fashion. Functionally, PCAT6 overexpression promoted NED of C4-2 cells, as evidenced by an increased expression of NE markers (NSE, ChgA, and SYP), whereas PCAT6 knockdown in NCI-H661 cells repressed NED. Furthermore, PCAT6 overexpression promoted PCa cell proliferation and invasion in vitro and in vivo. Mechanistically, PCAT6 functioned as competing endogenous (ce) RNA via absorbing miR-326, thus resulting in a de-suppression of Hnrnpa2b1 target gene. The current results demonstrate that PCAT6 acted as a tumor activator in PCa progression by sponging miR-326 and increasing Hnrnpa2b1 expression and that the PCAT6/miR-326/Hnrnpa2b1 signaling might be a new therapeutic target for PCa.

Long Non-coding RNA AFAP1-AS1 Facilitates Prostate Cancer Progression by Regulating miR-15b/IGF1R Axis.

BACKGROUND: Prostate cancer (PCa) is a commonly diagnosed malignant cancer and is the second- highest cause of cancer death in men worldwide. Enzalutamide is the second-generation inhibitor of androgen receptor signaling and is the fundamental drug for the treatment of advanced PCa. However, the disease will eventually progress to metastatic castration-resistant prostate cancer (CRPC) and aggressive neuroendocrine prostate cancer (NEPC) because of androgen-deprivation therapy (ADT) resistance. The aim of the study was to investigate the role of long non-coding RNA (lncRNA) AFAP1-AS1 in ADT resistance. METHODS: Quantitative real-time PCR analysis (qPCR) was used to assess the expression of AFAP1-AS1 in PCa cell lines and tissues. Cell proliferation and invasion were assessed after AFAP1-AS1 knockdown using Cell Counting Kit (CCK)-8 and Transwell assay, respectively. A dual-luciferase reporter gene assay was carried out to validate the regulatory relationship among AFAP1-AS1, microRNA (miR)-15b, and insulin-like growth factor1 receptor (IGF1R). RESULTS: AFAP1-AS1 level was markedly increased in castration-resistant C4-2 cells and NE-like cells (PC3, DU145, and NCI-H660), compared with androgen-sensitive LNCaP cells. Enzalutamide treatment increased the expression of AFAP1-AS1 in vitro and in vivo. Functionally, AFAP1-AS1 knockdown repressed tumor cell proliferation and invasion. Mechanistically, AFAP1-AS1 functioned as an oncogene in PCa through binding to miR-15b and destroying its tumor suppressor function. Finally, we identified that AFAP1-AS1 up-regulated IGF1R expression by competitively binding to miR-15b to de-repress IGF1R. CONCLUSION: AFAP1-AS1 facilitates PCa progression by regulating miR-15b/IGF1R axis, indicating that AFAP1-AS1 may serve as a diagnostic biomarker and therapeutic target for PCa.

SB203580, a p38 mitogen-activated protein kinase inhibitor, suppresses the development of endometriosis by down-regulating proinflammatory cytokines and proteolytic factors in a mouse model.

BACKGROUND: p38 mitogen-activated protein kinase (p38 MAPK), a regulator of inflammation, may play a role in the pathogenesis of endometriosis (EM). We studied the effect of SB203580, a p38 MAPK inhibitor, on the development of EM in a mouse model. METHODS: EM was induced in BALB/c mice by peritoneal injection of endometrium-rich fragments. Mice (n = 15) were injected i.p. for 24 days with SB203580 and 15 mice served as positive controls (EM group). Sham-operated mice received carrier only. Peritoneal fluid (PF) cells were collected for protein/mRNA analysis. Interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, matrix metalloproteinase-2 (MMP-2) and MMP-9 proteins were measured using enzyme-linked immunosorbent assay and mRNAs by RT-PCR. Phosphorylation of p38 MAPK was evaluated by western blotting. RESULTS: SB203580 decreased the weight and size (P < 0.05 versus EM) of endometriotic lesions in BALB/c mice. IL-1ß, TNF-α, MMP-2 and MMP-9 mRNA levels were decreased in peritoneal cells of the SB203580 versus EM group (P < 0.01, P < 0.05, P < 0.05 and P < 0.05, respectively). Concentrations of IL-1ß, TNF-α, MMP-2 and MMP-9 proteins in PF were reduced in the SB203580 versus EM group (P < 0.05, P < 0.01, P < 0.05 and P < 0.05, respectively). Compared with the sham-operated group, phosphorylation of p38 MAPK in the EM group was increased, and this was down-regulated by SB203580 (P < 0.01). CONCLUSIONS: SB203580 may suppress the development of EM by inhibiting expression of proinflammatory cytokines and proteolytic factors. p38 MAPK might play a key role in progression of EM.

[The action of p38 MAP kinase and its inhibitors on endometriosis].

Endometriosis, an oestrogen-dependent disorder, is related to inflammation, p38 Mitogen activated protein kinases (p38 MAPK) can be activated by sex hormone and inflammatory factors, which plays an important role in many cellular reactions such as apoptosis, proliferation, inflammation and stresses, etc. Many studies showed that p38 MAPK was participated directly in regulating the pathogenesis of endometriosis. The special regulatory action of p38 MAPK on sex hormone and inflammation may help us to understand the intricate endometriosis pathological hypothesis. p38 MAPK inhibitors play a key role in the the study of endometriosis, and show great promise for the future. Blocking and regulating the expression of p38 MAPK on the signal transduction pathway level may hope to be a new strategy to prevent and treat endometriosis.

[Association of CTLA-4 + 49A/G and CT60 gene polymorphism with type 1 diabetes and thyroid autoimmunity].

OBJECTIVE: To investigate the association of CTLA-4 + 49A/G and CT60 gene polymorphisms with type 1 diabetes (T1DM) and thyroid autoimmunity. Subjects Three hundred thirty-two T1DM patients and 476 controls were recruited in the study. METHOD: The CTLA-4 + 49 A/G and CT60 polymorphisms of CTLA-4 gene were analyzed by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method. Thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) were determined by radioimmunoassay. Glutamic acid decarboxylase antibody (GADA) and protein tyrosine phosphatase antibody (IA-2A) were measured by radioligand immunoassay. RESULTS: (1) The CTLA-4 + 49 A/G polymorphism was significantly associated with T1DM complicated with thyroid autoimmunity (OR = 2.43, P < 0.01) and with T1DM alone (OR = 1.66, P < 0.05). (2) The CTLA-4 CT60 polymorphism was also significantly associated with T1DM complicated with thyroid autoimmunity (OR = 2.67, P < 0.01) and with T1DM alone (OR = 1.60, P = 0.02). (3) T1DM with thyroid autoimmunity was characterized by a significantly higher frequency of CTLA-4 CT60 GG genotype (77.8% vs 62.3%, P < 0.05) and GADA (77.8% vs 57.4%, P < 0.05) compared to the patients without thyroid antibodies. CONCLUSION: CTLA-4 + 49 A/G and CT60 gene polymorphism confers genetic susceptibility to type 1 diabetes, particularly in patients with thyroid autoimmunity.

[Immunological characteristics and islet function in first-degree relatives of latent autoimmune diabetes in adults].

OBJECTIVE: To investigate the immunological features and pancreatic beta cell function of first-degree relatives of latent autoimmune diabetes in adults (LADA). METHODS: Oral glucose tolerance test (OGTT) was performed in 209 first-degree relatives of LADA patients and 340 first-degree relatives of classic T1DM patients. Radioligand assay was used to detect glutamic acid decarboxylase antibody (GADAb) and protein tyrosine phosphatase antibody (IA-2Ab). Intravenous glucose tolerance tests were performed in 39 normal controls and 46 first-degree relatives. Among them, 9 were GAD-Ab positive and 9 GAD-Ab negative first-degree relatives of patients with LADA while 12 were GAD-Ab positive and 16 GAD-Ab negative first-degree relatives of patients with classic T1DM. RESULTS: (1) Immunological characteristics of first-degree relatives of patients with LADA. Similar with the first-degree relatives of patients with classic T1DM (18/340, 5.3%), the detection rate of GAD-Ab was 4.3% (9/209) in first-degree relatives of patients with LADA. (2) Islet function of first-degree relatives of patients with LADA. Compared with the control group, the first phase insulin release and the first phase insulin peak secretion averages were lower in the antibody positive group of first-degree relatives of patients with LADA (P < 0.05); HOMA-IR was higher in the antibody negative group of first-degree relatives of patients with LADA (P < 0.05). (3) Analysis on glucose metabolism of different immune status for first-degree relatives of patients with LADA. (1) The detection rate of impaired glucose tolerance (IGT) was 16.7% (35/209) and diabetes (DM) rate 10.0% (21/209). (2) The detection rate of IGT was higher in the antibody positive group than the antibody negative group in first-degree relatives of patients with LADA (37.5% vs 15.0%, P < 0.05). CONCLUSIONS: Among first-degree relatives of patients with LADA, a certain extent of islet autoimmune antibody markers could be measured, and insulin resistance and insulin secretion defects were detected. The rate of IGT was higher in the antibody positive group than the antibody negative group.

[Immunological features of fulminant type 1 diabetes].

OBJECTIVE: To investigate the immunological features of fulminant type 1 diabetes. METHODS: Twenty patients with fulminant type 1 diabetes (F1D) were recruited based upon the criteria proposed by Hanafusa, and 40 patients with classical type 1 diabetes were matched with age, gender and duration for comparison. GADA, IA2A and ZnT8A were determined with radioligand assay, and GAD-reactive T cells were measured by enzyme-linked immunospot (ELISPOT) assay. The HLA-DQ were analyzed by sequence-based genotyping (SBT). RESULTS: Eight of 20 patients with F1D were antibody-positive, including 7 GADA positive, 4 ZnT8A positive, and 3 both GADA and ZnT8A positive. The index of 3 GADA positive patients were less than 0.4 at first visit, two turned to be negative by two or three years. While the GADA index of the patient was 0.343 at onset and increased to 1.467 three years later. Among subjects with F1D (3/6) and classical type 1 diabetes (3/6), were recorded significant GAD-stimulated responses by ELISPOT assay. The frequencies of HLA-DQA1*0102-DQB1*0601 and DQA1*03-DQB1*0401 were significantly higher in F1D than those in classical type 1 diabetes (P = 0.005, P = 0.035, respectively). CONCLUSION: Humoral and cellular immunoreactivity and susceptible HLA-DQ genotype existed in part of F1D patients, indicating autoimmunity may involve in the pathogenesis of F1D.

[Dual regulation of cell cycles by Shuanghuang Shengbai Granule in Lewis-bearing mice with chemotherapy-induced myelosuppression and its mechanism].

OBJECTIVE: To explore the dual regulatory effects of Shuanghuang Shengbai Granule, a compound traditional Chinese herbal medicine, on cell cycle in Lewis-bearing mice with chemotherapy-induced myelosuppression. METHODS: Thrity Lewis-bearing mice were randomly divided into control group, untreated group and treated group. A model of myelosuppression was established by peritoneal injection of cyclophosphamide to Lewis-bearing mice. Mice in the treated group were treated with Shuanghaung Shengbai Granule for 6 days. Cell cycle progressions of cells collected from bone marrow and tumor tissues were assayed by flow cytometry, and proliferation index (PI) was also calculated. Expressions of cyclin-dependent kinase 4 (CDK4), cyclin-dependent kinase 6 (CDK6) and cyclin D1 in bone marrow and tumor tissues were detected by Western blotting and immunohistochemical method. RESULTS: Percentages of bone marrow and tumor cells in G0/G1 phase in the untreated group were lower than those in the control group; however, the PI of untreated group was higher than that of the control group. The expressions of CDK4, CDK6 and cyclin D1 in bone marrow and tumor tissues in the untreated group were increased as compared with the control group. Compared with the untreated group and the control group, the percentage of bone marrow cells in G0/G1 phase was decreased, and the PI of bone marrow cells and the expressions of CDK4, CDK6 and cyclin D1 were increased in bone marrow in the treated group. However, the percentage of tumor cells in G0/G1 phase in the treated group was increased, and the PI of tumor cells and the expressions of CDK4, CDK6 and cyclin D1 in tumor tissues were decreased as compared with the untreated and control groups. CONCLUSION: Shuanghuang Shengbai Granule may have a function of cell cycle dual regulation in Lewis-bearing mice with chemotherapy-induced myelosuppression by regulating the expressions of CDK4, CDK6 and cyclin D1 in bone marrow and tumor tissues.

Lead enrichment in different genotypes of rice grains.

Using environmental scanning electron microscopy and X-ray electron probe microanalysis, the lead content was studied in inner and outer surface of rice glume, surface of caryopsis, center of caryopsis, near aleuronic layer and aleuronic layer in 21 genotypes of rice grains. The results showed that the lead content in different part of 21 genotypes of rice grains changed as inner surface of rice glume > aleuronic layer > near aleuronic layer > surface of caryopsis > outer surface of rice glume > center of caryopsis. There were genetic differences in lead enrichment in different genotypes of rice grains, which reflected as the differences of lead content in the same part and different part of rice grains. In different genotypes of rice grains, there were significant non-linear correlations between lead content in the inner surface of rice glume, center of caryopsis, aleuronic layer and that in the other parts of rice grain. The results also indicated that the lead enrichment in the center of caryopsis regulated by glume and aleuronic layer. In addition, in different genotypes of rice grains, there were differences in regulation of lead enrichment among different parts, which changed non-linearly.

[Using MSR model to analyze the impact of gene-gene interaction with related to the genetic polymorphism of metabolism enzymes on the risk of breast cancer].

OBJECTIVE: To identify the interactions of susceptive genes with related to the genetic polymorphism of metabolism enzymes (CYP1A1, GSTT1 and GSTM1) and their impacts on the risk of breast cancer; and to test the feasibility of using Multifactor Dimensionality Reduction (MDR) model in analyzing gene-gene interactions. METHODS: A paired case-control study, matched by age and menstruate state, was conducted. From December 2003 to September 2004, 78 pairs of people with and without breast cancers were investigated. The variant genotypes of CYP1A1 Msp I and GSTT1/M1 were identified by PCR-RFLP and multiplex PCR assays. The gene-gene interactions were analyzed with the MDR model. Based on the result of the MDR model, a conditional logistic regression model was constructed as the final cause-effect interpretative model. RESULTS: The interaction between CYP1A1 Msp I variant genotype (vv) and GSTT1 null genotype gave the best MDR model with statistical significance (Sign Test, P = 0.05). The model Testing Balance Accuracy was 0. 5920. The Cross-Validation consistency was 10/10. The final conditional logistic regression based on the MDR model showed that passive smoking, abortion and gene-gene interaction were risks of breast cancers, with an OR (95% confidence interval) of 12.234 (1.7459-85.7279), 4.554 (1.3250-15.6507) and 9.597 (1.5783-58.3599), respectively. CONCLUSION: The MDR model may be an effective method for estimating risks of breast cancers due to gene-gene and gene-environment interactions. The gene-gene interaction with related to the genetic polymorphism of metabolism enzymes (CYP1A1 and GSTT1) may increase the risk of breast cancer by disturbing the metabolism of estrogen.