Vitrectomy with internal limiting membrane peeling versus its flap insertion for macular hole in high myopia: a Meta-analysis.

AIM: To compare the anatomic and functional outcomes between vitrectomy with internal limiting membrane (ILM) peeling and internal ILM flap insertion technique for high myopia macular hole (MH). METHODS: PubMed, Cochrane Library, EMBASE, and CNKI were systematically searched, and all studies involved MH were included. The closure rate of MH and the postoperative best-corrected visual acuity (BCVA) at 6mo after the initial surgery were the primary measures. All statistical tests were performed in Review Manager 5.3. RESULTS: Five studies that included 151 eyes of 151 patients were finally included, all of which were retrospectively comparative studies. Between the pars plana vitrectomy (PPV) with ILM peeling surgery and the ILM insertion technique, the latter had significantly better efficacy with respect to the closure rate of MH (OR=21.32, 95%CI=7.25-62.67, P<0.001); However, regarding BCVA at 6mo after the initial surgery in MH, there was no statistical significance between the groups (OR=-0.04, 95%CI=-0.22-0.14, P=0.66). In addition, regarding the rate of retinal reattachment after the initial surgery, the two different methods were not significantly different (OR=2.22, 95%CI=0.34-14.32, P=0.4). CONCLUSION: Both ILM peeling and ILM insertion technique could significantly improve anatomic outcomes of MH in high myopia with or without retinal detachment (RD), and anatomic outcomes are more effective. However, there is no statistical significance in BCVA at 6mo after the initial surgery in MH, or in the rate of retinal reattachment after the first surgery, between the two methods.

Risk factors for postoperative recurrence of ovarian endometriosis: long-term follow-up of 358 women.

OBJECTIVE: To explore the risk factors for the recurrence of endometrioma and the risk factors for the recurrence of endometriosis-related pain after long-term follow-up. METHODS: This study retrospectively analyzed 358 women with endometriomas who had a minimum of 5-years follow up after laparoscopic endometrioma excision, which was performed at Peking Union Medical College Hospital from January 2009 to April 2013. All women were divided into recurrence group and nonrecurrence group. Analysis was performed with regard to preoperative history, laboratory analysis, findings during surgery, and symptoms during follow-up, including improvement and recurrence. RESULTS: The cumulative incidence rates of recurrence from 5 to 10 years after surgery were 15.4, 16.8, 19.3, 22.5, 22.5, and 22.5%, respectively. Significant differences were found between two groups in terms of age at surgery (RR: 0.764, 95% CI: 0.615-0.949, p = 0.015), duration of dysmenorrhea (RR: 1.120, 95% CI: 1.054-1.190, p < 0.001), presence of adenomyosis (RR: 1.629, 95% CI: 1.008-2.630, p = 0.046), CA125 level (RR: 1.856, 95% CI: 1.072-3.214, p = 0.021) and severity of dysmenorrhea. The severity of dysmenorrhea (RR: 1.711, 95% CI: 1.175-2.493, p = 0.005) and postoperative pregnancy (RR: 0.649, 95% CI: 0.460-0.914, p = 0.013) were significantly correlated with endometrioma recurrence in the multivariate analysis. No significant associations were found between the recurrence rate and gravida, parity, body mass index, infertility, leiomyoma presence, the size of ovarian endometrioma, the presence of deep infiltrating endometriosis, disease stage or postoperative medication. CONCLUSIONS: The severity of dysmenorrhea and postoperative pregnancy were independent risk factors for the recurrence of ovarian endometriomas after surgery during the long-time follow up.

[Research Advances in Ocular Myasthenia Gravis].

Ocular myasthenia gravis(OMG)is an autoimmune disease caused by neuromuscular junction transmission disorders and manifested mainly as fluctuating blepharoptosis and diplopia,with the extraocular muscles as the main involveed sites.While the pathogenesis of OMG remains unclear,some antibodies,complements,and cytokines may be the contributing factors.The diagnosis and treatment of OMG have been defined in recent years.This article reviews the pathogenesis,diagnosis,and treatment of OMG.

[Advances in Retinopathy of Prematurity].

Retinopathy of prematurity(ROP)is a pathological neovascularization with fibrotic changes in the fundus of premature infants.It is a major cause of preventable blindness in children in both developing and developed countries.Treatment of ROP has long been a hot research topic in ophthalmology and pediatrics.With a clearer knowledge of the pathogenesis of ROP,more basic and clinical studies have been carried out.The anti-vascular endothelial growth factor therapy and surgical treatment have become mature strategies,and a variety of therapeutic drugs including insulin-like growth factor-1,transforming growth factor-ß,polyunsaturated fatty acids,and ß-adrenergic receptor blockers have been developed.This article reviews the recent advances in ROP.

[Mechanism of Th1/Th2 Cytokines in HLA-DQ8 Transgenic Mice Model of Ocular Experimental Autoimmune Myasthenia Gravis].

Objective To analyze the levels of cytokines (IL-2,IFN-γ,IL-6,IL-10) associated with Th1 and Th2 cells in HLA-DQ8 transgenic mice model of ocular experimental autoimmune myasthenia gravis (oEAMG) induced by recombinant H-AChR γ subunit immunization.Methods DQ8 mice were immunized with 20 µg of AChR γ subunit,20 µg of crude E. coli extract (E. coli group),or complete Freund's adjuvant (CFA) only (CFA group). All mice were immunized on days 0,30,and 60. Mice were euthanized 28 days after the third immunization,and draining lymph node cells (LNC) and spleen lymphocytes were cultured in vitro. The supernatant was collected to observe the interleukin(IL)-2,interferon(IFN)-γ,IL-6,IL-10 production by ELISA.Results LNCs and spleen lymphocytes of H-AChR γ subunit-immunized mice exhibited significantly enhanced IFN-γ (F=76.332,P<0.001;F=34.865,P<0.001) and IL-2 (F=42.835,P<0.001;F=38.030,P<0.001),which associated with Th1 cells,as compared to E. coli group and CFA group. There were no significant differences in IL-6 (F=1.325,P=0.284;F=1.935,P=0.166) and IL-10 (F=0.908,P=0.417;F=1.189,P=0.322) levels,which secreted by Th2 cells,among these three groups.Conclusion Th1 cytokines play key roles in the pathogenesis of oEAMG,while the mechanism of Th2 cytokines for oEAMG remains unclear.

Abnormal resting-state functional network centrality in patients with high myopia: evidence from a voxel-wise degree centrality analysis.

AIM: To investigate the functional networks underlying the brain-activity changes of patients with high myopia using the voxel-wise degree centrality (DC) method. METHODS: In total, 38 patients with high myopia (HM) (17 males and 21 females), whose binocular refractive diopter were -6.00 to -7.00 D, and 38 healthy controls (17 males and 21 females), closely matched in age, sex, and education levels, participated in the study. Spontaneous brain activities were evaluated using the voxel-wise DC method. The receiver operating characteristic curve was measured to distinguish patients with HM from healthy controls. Correlation analysis was used to explore the relationship between the observed mean DC values of the different brain areas and the behavioral performance. RESULTS: Compared with healthy controls, HM patients had significantly decreased DC values in the right inferior frontal gyrus/insula, right middle frontal gyrus, and right supramarginal/inferior parietal lobule (P<0.05). In contrast, HM patients had significantly increased DC values in the right cerebellum posterior lobe, left precentral gyrus/postcentral gyrus, and right middle cingulate gyrus (P<0.05). However, no relationship was found between the observed mean DC values of the different brain areas and the behavioral performance (P>0.05). CONCLUSION: HM is associated with abnormalities in many brain regions, which may indicate the neural mechanisms of HM. The altered DC values may be used as a useful biomarker for the brain activity changes in HM patients.

Identification of Circular RNAs as a Novel Biomarker for Ovarian Endometriosis.

BACKGROUND: Endometriosis is a challenging disease with symptoms such as dysmenorrhea and infertility. However, its etiology is still vague and there is still no effective markers or treatment. This study aimed to profile the circular RNAs (circRNAs) expressed in eutopic endometrium from patients with ovarian endometriosis and explore potential clues to the pathogenesis of endometriosis, providing an evidence for clinical diagnosis and treatment. METHODS: A total of 63 clinical samples, including control endometrium (n = 22) and eutopic endometrium (n = 41), were collected from Peking Union Medical College Hospital between May 1, 2016, and December 31, 2016. Of them, four samples in each group were used for circRNA microarray. Then, four upregulated circRNAs were screened out for quantitative real-time polymerase chain reaction (qRT-PCR) validation. After that, bioinformatics analysis was performed to predict miRNAs targeted by validated circRNAs and investigate the circRNA-miRNA-mRNA interactions. RESULTS: Among 88 differentially expressed circRNAs, 11 were upregulated and 77 were downregulated in eutopic endometrium of patients with endometriosis. qRT-PCR validation results for two upregulated circRNAs (circ_0004712 and circ_0002198) matched the microarray results. The area under the receiver operating characteristic curve of circ_0002198 for distinguishing ovarian endometriosis was 0.846 (95% confidence interval [CI]: 0.752-0.939; P < 0.001) while that of circ_0004712 was 0.704 (95% CI: 0.571-0.837; P = 0.008). On the basis of target prediction, we depicted the molecular interactions between the identified circRNAs and their dominant target miRNAs, as well as constructed a circRNA-miRNA-mRNA network. CONCLUSIONS: This study provides evidence that circRNAs are differentially expressed between eutopic and normal endometrium, which suggests that circRNAs are candidate factors in the activation of endometriosis. circ_0002198 and circ_0004712 may be potential novel biomarkers for the diagnosis of ovarian endometriosis.

The prognostic value of lymphocyte-to-monocyte ratio in retinopathy of prematurity.

AIM: To evaluate the associations between development of retinopathy of prematurity (ROP) and serum lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR). METHODS: A retrospective cohort study was performed, involving infants who were screened for ROP from January 2015 to December 2015. Preterm newborns of ≤32 gestational weeks with ROP were enrolled as the observation group, and non-ROP infants were enrolled as the control group, whose complete blood cell were measured within the first 24h of life. The levels of NLR, LMR and PLR were determined in all groups. The data obtained were analyzed using univariate and multivariate logistic regression analysis. RESULTS: In this study, 40 cases of ROP were enrolled and 40 cases of non-ROP as controls. The LMR levels were significantly higher (P<0.001) in ROP group (3.96±1.16) compared to non-ROP group (2.85±0.79). The NLR levels were significantly lower (P=0.035) in ROP group {median [interquartile range (IQR)], 0.88 (0.67-1.46)} compared to non-ROP group [median (IQR), 1.20 (0.85-1.89)]. The median PLR values were 61.99 (IQR, 50.23-75.98) in ROP group and 69.24 (IQR, 55.52-88.12) in non-ROP group (P=0.104). Logistic regression analysis suggested that LMR was an independent risk factor for ROP (OR: 0.275; 95% CI: 0.134-0.564; P=0.001). CONCLUSION: The findings demonstrate that higher LMR is independently and significantly associated with the development of ROP, and the LMR may be invoked as a predictive tool for identifying risk for ROP.

Menorrhagia and Uterine Volume Associated with Lower Urinary Tract Symptoms in Patients with Adenomyosis.

BACKGROUND: Adenomyosis is a gynecological disorder with symptoms most presenting as dysmenorrhea and heavy menstrual bleeding. However, the presence of lower urinary tract symptoms (LUTS) among women with adenomyosis remains unclear. This study was designed to determine the prevalence of LUTS and factors related to the severity of these symptoms in this population. METHODS: From July 2016 to November 2016, a total of 298 untreated symptomatic adenomyosis patients and 280 age-matched controls were enrolled. Demographics, LUTS, pain symptoms, ultrasonographic uterine size, and serum CA125 level were recorded. LUTS were evaluated using the International Prostate Symptom Score (IPSS) questionnaire. Factors related to the severity of LUTS were detected using the logistic regression analysis presented as odds ratio (OR) and 95% confidence interval (CI). RESULTS: Compared with the control group, patients with adenomyosis had a greater IPSS total (4 [2-8] vs. 2 [0-3], Z = -8.159, P 0.001), IPSS storage (2 [1-4] vs. 1[0-2], Z = -7.361 P 0.001), and IPSS voiding (2 [0-4] vs. 0 [0-1], Z = -7.194, P 0.001). Of the patients with adenomyosis, 30.2% had moderate-to-severe lower urinary tract symptoms (IPSS ≥8). The most prevalent LUTS were daytime frequency (40.9%), followed by nocturia (24.8%), weak stream (24.2%), and incomplete emptying (23.5%). In study group, patients with an IPSS total score ≥8 had higher proportion of menorrhagia (51.1% vs. 30.8%, χ2= 11.162 P= 0.025) and larger uterine volumes (183.3 [109.8-273.8] cm3 vs. 148.5 [96.4-262.7] cm3, Z = -1.441, P= 0.150) compared to patients with an IPSS total score <8. On multivariate logistic regression analysis, patients with menorrhagia were associated with an increased risk of an IPSS total score ≥8 (OR: 2.309, 95% CI: 1.310-4.070, P= 0.004), an IPSS storage subscore ≥4 (OR: 2.422, 95% CI: 1.395-4.206, P= 0.002), and an IPSS voiding subscore ≥5 (OR: 1.971, 95% CI: 1.176-3.302, P= 0.010). However, patients with uterine volume more than 180 cm3 had more than 2-fold risk of bearing IPSS total score ≥8 (OR: 2.437, 95% CI: 1.381-4.300, P= 0.002), IPSS storage subscore ≥4 (OR: 2.486, 95% CI: 1.433-4.314, P= 0.001), and IPSS voiding subscore ≥5 (OR: 2.700, 95% CI: 1.485-4.908, P= 0.001). CONCLUSIONS: Lower urinary tract symptoms are prevalent in patients with symptomatic adenomyosis and greatly affect patients' quality of life. Menorrhagia and large uterine volume could be potential risk factors that increase the occurrence of moderate-to-severe LUTS.

Sevoflurane postconditioning attenuates reactive astrogliosis and glial scar formation after ischemia-reperfusion brain injury.

Cerebral ischemia leads to astrocyte's activation and glial scar formation. Glial scar can inhibit axonal regeneration during the recovery phase. It has demonstrated that sevoflurane has neuroprotective effects against ischemic stroke, but its effects on ischemia-induced formation of astrogliosis and glial scar are unknown. This study was designed to investigate the effect of sevoflurane postconditioning on astrogliosis and glial scar formation in ischemic stroke model both in vivo and in vitro. The results showed that 2.5% of sevoflurane postconditioning could significantly reduce infarction volume and improve neurologic deficits. And it could also decrease the expression of the glial scar marker glial fibrillary acidic protein (GFAP), neurocan and phosphacan in the peri-infarct region and markedly reduce the thickness of glial scar after ischemia/reperfusion (I/R). Consistent with the in vivo data, in the oxygen and glucose deprivation/reoxygenation (OGD/Re) model, sevoflurane postconditioning could protect astrocyte against OGD/Re-induced injury, decrease the expression of GFAP, neurocan and phosphacan. Further studies demonstrated that sevoflurane postconditioning could down-regulate the expression of Lamp1 and active cathepsin B, and block I/R or OGD/Re-induced release of cathepsin B from the lysosomes into cytoplasm. In order to confirm whether inhibition of cathepsin B could attenuate the formation of glial scar, we used cathepsin B inhibitor CA-074Me as a positive control. The results showed that inhibition of cathepsin B could decrease the expression of GFAP, neurocan and phosphacan. Taken together, sevoflurane postconditioning can attenuate astrogliosis and glial scar formation after ischemic stroke, associating with inhibition of the activation and release of lysosomal cathepsin B.

Altered spontaneous brain activity pattern in patients with high myopia using amplitude of low-frequency fluctuation: a resting-state fMRI study.

OBJECTIVE: Many previous reports have demonstrated significant neural anatomy changes in the brain of high myopic (HM) patients, whereas the spontaneous brain activity changes in the HM patients at rest are not well studied. Our objective was to use amplitude of low-frequency fluctuation (ALFF) method to investigate the changes in spontaneous brain activity in HM patients and their relationships with clinical features. METHODS: A total of 38 patients with HM (17 males and 21 females) and 38 healthy controls (HCs) (17 males and 21 females) closely matched in age, sex, and education underwent resting-state functional magnetic resonance imaging scans. The ALFF method was used to assess local features of spontaneous brain activity. The relationship between the mean ALFF signal values in many brain regions and the clinical features in HM patients was calculated by correlation analysis. RESULTS: Compared with HCs, the HM patients had significantly lower ALFF in the right inferior and middle temporal gyrus, left middle temporal gyrus, left inferior frontal gyrus/putamen, right inferior frontal gyrus/putamen/insula, right middle frontal gyrus, and right inferior parietal lobule and higher ALFF values in the bilateral midcingulate cortex, left postcentral gyrus, and left precuneus/inferior parietal lobule. However, no relationship was found between the mean ALFF signal values of the different areas and the clinical manifestations in HM. CONCLUSION: The HM patients were affected with brain dysfunction in many regions, which may indicate the presence of neurobiological changes involving deficits in language understanding and attentional control in HM patients.

[Strong and tunable field enhancement obtained by periodic rectangular pit structure].

The authors have designed a novel type of periodic rectangular pit nanostructure substrate based on the surface plasmon principle. Finite element method was employed to simulate the optical near-field distribution. Strongly enhanced field whose electric intensity Emax/E0 can be as high as 20 at resonance frequency appears around pithead of the periodic structure. As the period of structure, pit length l, width w and environment change, the authors observe the regular shifting of plasmon resonant wavelength which can cover the range from 500 to 1000 nm. The red shifts of SPR resonance peaks are increased with the increment of period Px when incident light is polarized along x axis. An abrupt decrease in localized electric field in the pit is observed as incident wavelength approaches Px. This is due to the satisfaction of wave vector matching condition and the excitation of propagating SPP. SPR resonance peaks also red shifts with the increment on pit length l and environment dielectric refractive index, presenting a linear dependence with pit length l. While the resonance peaks are blue shifted with the increment of pit width w. The results presented in this paper will provide a way to tune the plasmon resonant wavelength. Inspired by Jain's report, SPR resonance peaks' shifting with the changing of structure parameters can be explained by viewing the rectangular pit nanostructure as combination of two pairs of dipole-dipole coupling models along x and y axis respectively.

[Rapid quantitative analysis of hydrocarbon composition of furfural extract oils using attenuated total reflection infrared spectroscopy].

A set of rapid analysis system for hydrocarbon composition of heavy oils was designed using attenuated total reflection FTIR spectrometer and chemometrics to determine the hydrocarbon composition of furfural extract oils. Sixty two extract oil samples were collected and their saturates and aromatics content data were determined according to the standard NB/SH/T0509-2010, then the total contents of resins plus asphaltenes were calculated by the subtraction method in the percentage of weight. Based on the partial least squares (PLS), calibration models for saturates, aromatics, and resin+asphaltene contents were established using attenuated total reflection FTIR spectroscopy, with their SEC, 1.43%, 0.91% and 1.61%, SEP, 1.56%, 1.24% and 1.81%, respectively, meeting the accuracy and repeatability required for the standard. Compared to the present standard method, the efficiency of hydrocarbon composition analysis for furfural extract oils is significantly improved by the new method which is rapid and simple. The system could also be used for other heavy oil analysis, with excellent extension and application foreground.

Significance of serum procalcitonin as biomarker for detection of bacterial peritonitis: a systematic review and meta-analysis.

BACKGROUND: Bacterial peritonitis is serious disease and remains a diagnostic challenge for clinicians. Many studies have highlighted the potential usefulness of procalcitonin (PCT) for identification of bacterial peritonitis, however, the overall diagnostic value of PCT remains unclear. Therefore, we performed a meta-analysis to assess the accuracy of PCT for detection of bacterial peritonitis. METHODS: We performed a systematic searched in MEDLINE, EMBASE, SCOPUS, China Biology Medicine Database (CBM), China National Knowledge Infrastructure Database (CNKI) and Cochrane databases for trials that evaluated the diagnostic role of PCT for bacterial peritonitis. Sensitivity, specificity and other measures of accuracy of PCT were pooled using bivariate random effects models. RESULTS: Eighteen studies involving 1827 patients were included in the present meta-analysis. The pooled sensitivity and specificity of serum PCT for the diagnosis bacterial peritonitis were 0.83 (95% CI: 0.76-0.89) and 0.92 (95% CI: 0.87-0.96), respectively. The positive likelihood ratio was 11.06 (95% CI: 6.31-19.38), negative likelihood ratio was 0.18 (95% CI: 0.12-0.27) and diagnostic odds ratio (DOR) was 61.52 (95% CI: 27.58-137.21). The area under the receiver operating characteristic curve (AUROC) was 0.94. Use of a common PCT cut-off value could improve the DOR to 75.32 and the AUROC to 0.95. Analysis of the seven studies that measured serum C-reactive protein (CRP) indicated that PCT was more accurate than CRP for the diagnosis of bacterial peritonitis. CONCLUSIONS: Our results indicate that PCT determination is a relatively sensitive and specific test for the diagnosis of bacterial peritonitis. However, with regard to methodological limitations and significant heterogeneity, medical decisions should be based on both clinical findings and PCT test results.

Effects of vitamin E-coated dialyzer on oxidative stress and inflammation status in hemodialysis patients: a systematic review and meta-analysis.

BACKGROUND: Vitamin E-coated dialyzer may have an effect on oxidative stress and inflammation status in hemodialysis (HD) patients. Therefore, we performed a systematic review to assess the anti-oxidation and anti-inflammatory effects of vitamin E-coated dialyzer in HD patients. METHODS: The randomized controlled trials (RCTs) and quasi-RCTs of vitamin E-coated dialyzer versus conventional dialyzer for HD patients were searched from multiple databases. We screened relevant studies according to predefined inclusion criteria and performed meta-analyses using RevMan 5.1 software. RESULTS: Meta-analysis showed vitamin E-coated dialyzer therapy could significantly decrease the serum thiobarbituric acid reacting substances (TBARS) (SMD, -0.95; 95% CI, -1.28 to -0.61; p < 0.00001), oxLDL (SMD, -0.61; 95% CI, -1.04 to -0.19; p = 0.005), interleukin-6 (IL-6) (SMD, -0.65; 95% CI, -0.97 to -0.32; p < 0.0001) and C-reactive protein (CRP) levels (SMD, -0.46; 95% CI, -0.87 to -0.05; p = 0.03) compared with that of the control group. However, vitamin E-coated dialyzer did not result in increasing the total antioxidant status (TAS) (SMD, 0.23; 95% CI, -0.16 to 0.61; p = 0.25) and the fractional clearance of urea index (Kt/v) levels (MD, -0.07; 95% CI, -0.14 to 0.00; p = 0.06), in addition, there was no significant difference in plasma superoxide dismutase (SOD) level compared with that of the conventional dialyzer & oral vitamin E group (SMD, 0.28; 95% CI, -0.20 to 0.75; p = 0.26). CONCLUSIONS: Vitamin E-coated dialyzer can reduce the oxidative stress and inflammation status reflected by the decreasing of serum TBARS, oxLDL, CRP, and IL-6 levels, and this new dialyzer does not affect the dialysis adequacy.

Is lead chelation therapy effective for chronic kidney disease? A meta-analysis.

The heavy metal lead (Pb) is a major environmental and occupational hazard. Epidemiological studies have demonstrated a strong association between lead exposure and the presence of chronic kidney injury. Some studies have suggested that chelation therapy with calcium disodium ethylenediaminetetraacetic acid (calcium disodium EDTA) might help decrease the progression of chronic kidney disease among patients with measurable body lead burdens. However, calcium disodium EDTA chelation in lead exposure is controversial due to the potential for adverse effects such as acute tubular necrosis. Therefore, we investigated the available randomized controlled trials assessing the renoprotective effects of calcium disodium EDTA chelation therapy. Our meta-analysis shows that calcium disodium EDTA chelation therapy can effectively delay the progression of chronic kidney disease in patients with measurable body lead burdens reflected by increasing the levels of estimated glomerular filtration rate (eGFR) and creatinine clearance rate (Ccr). There appears to be no conclusive evidence that calcium disodium EDTA can decrease proteinuria.

[The evaluation of hydrocarbon potential generation for source rocks by near-infrared diffuse reflection spectra].

Near-infrared (NIR) and mid-infrared (MIR) diffuse reflection spectra were compared and evaluated for hydrocarbon potential generation of source rocks. Near-infrared diffuse reflectance often exhibits significant differences in the spectra due to the non-homogeneous distribution of the particles, so the signal-to-noise ratio of NIR is much lower than MIR It is too difficult to get accurate results by NIR without using a strong spectral preprocessing method to remove systematic noise such as base-line variation and multiplicative scatter effects. In the present paper, orthogonal signal correction (OSC) and an improved algorithm of it, i.e. direct orthogonal signal correction (DOSC), are used as different methods to preprocess both the NIR and MIR spectra of the hydrocarbon source rocks. Another algorithm, wavelet multi-scale direct orthogonal signal correction (WMDOSC), which is a combination of discrete wavelet transform (DWT) and DOSC, is also used as a preprocessing method. Then, the calibration model of hydrocarbon source rocks before and after pretreatment was established by interval partial least square (iPLS). The experimental results show that WMDOSC is more successfully applied to preprocess the NIR spectra data of the hydrocarbon source rocks than other two algorithms, and NIR performed as good as MIR in the analysis of hydrocarbon potential generation of source rocks with WMDOSC-iPLS pretreatment calibration model.

[Using PAA template to fabricate SERS substrate and the SERS detection of melamine].

The authors have got silver film with orderly arranged nanoparticles as the surface-enhanced Raman spectra (SERS) substrates using porous anodic alumina templates (PAA). A silver film (99.99%) with the thickness of several millimeters was thermally evaporated onto the PAA templates and the SERS substrate was got after removing the PAA templates in hydrochloric acid. SERS spectra of pyridine (0.01 mol x L(-1)) were measured on Renishaw 2000 Ramanscope with a He-Ne (632.8 nm) laser as an excitation source in backscattering geometry, and the average enhancement factors were more than 10(5). The authors compared SERS spectra of pyridine from the SERS substrates and from Ag film evaporated directly on glass slide, and the former was 30 times stronger than the latter. The authors got different SERS spectra of pyridine while changing the excitation laser power. It was found that the relationship between the peak intensity of SERS spectra and the excitation laser power was linear as the normal Raman spectrum. We used the substrates to detect melamine, 2.5 mg x L(-1) melamine solution could be recognized al though excitation laser power was below 1 mW.

[Quantities analysis of the infrared diffuse reflection spectrum of hydrocarbon source rocks by OSC-iPLS].

In many cases, the scattering can be an overpowering contributor to the spectrum, sometimes accounting for most of the variance in the data. Although the degree of scattering is dependent on the wavelength of the light that is used and the particle size and refractive index of the sample, the scattering is not uniform throughout the spectrum. In order to remove the effects of scattering and noise on multivariate calibration of IR spectral signals, orthogonal signal correction (OSC) was used as a method to preprocess the infrared spectra of the hydrocarbon source rocks to be quantitatively determined, thus to establish the calibration model of hydrocarbon source rocks before and after pretreatment by inetval partial least square (iPLS). Pretreatment was smoother and more orderly array. This indicated that the major information in hydrocarbon source rocks spectra could be reserved while part of noise was removed by OSC method. In this study, pretreatment calibration model was obtained, the model's correlation coefficient is 0.994 04 and RMSE is 0.635 2, but with no pretreatment the calibration model's correlation coefficient is 0.770 9 and RMSE is 3.925 7.

[Raman spectra studies of MBE-grown n-GaAs/SI-GaAs films].

n-GaAs films doped with Si were grown by MBE on semi-insulated GaAs (100) substrates. The films with different doping concents were characterized by Raman spectra at room temperature. It is obviously that the Raman peaks shifted. Some peaks were enhanced and some were weakened. This is attributed to the fact that the higher the doping contents, the highertge lattice mismatch. And the lattice misfit induced the imperfection in epitaxy layers. This experimental result coincides with the theory.