Theoretical study on the Cerenkov-type second-harmonic generation in optical superlattices without paraxial approximation.

In this paper, the Cerenkov-type second-harmonic generation in bulk optical superlattices has been studied theoretically with the non-paraxial wave equations, where the paraxial approximation is avoided. The corresponding phase-matching condition is determined strictly by solving the non-paraxial wave equations under proper boundary conditions, and the result coincides well with the traditional Cerenkov phase-matching condition. In addition, a backward Cerenkov phase-matching condition is deduced from the wave equations as well, and the physical requirement of this condition is clarified.

2D wave-front shaping in optical superlattices using nonlinear volume holography.

Nonlinear volume holography is employed to realize arbitrary wave-front shaping during nonlinear processes with properly designed 2D optical superlattices. The concept of a nonlinear polarization wave in nonlinear volume holography is investigated. The holographic imaging of irregular patterns was performed using 2D LiTaO3 crystals with fundamental wave propagating along the spontaneous polarization direction, and the results agree well with the theoretical predictions. This Letter not only extends the application area of optical superlattices, but also offers an efficient method for wave-front shaping technology.

Nonlinear optical Fourier transform in an optical superlattice with "x+2" structure.

We proposed a simple method to realize optical Fourier transform during the nonlinear wave shaping processes. In this method, an integrated optical superlattice is designed to realize multiple optical functions, which plays important roles in both the nonlinear harmonic generation process and the optical Fourier Transform process. We demonstrated our method by the nonlinear generation of Airy beams as an example. It is a universal method for beam shaping and is of practical importance for designing compact nonlinear optical devices.

[One-step methylation variable position analysis technology in single-tube].

OBJECTIVE: To develop the single-tube one-step methylation variable position (MVP) analysis technology-single-tube post-digestion PCR-melting curve analysis (PDP-MCA). METHODS: Based on differentially methylated region (DMR) reported previously as the model, a set of primers with different melting temperatures of products in the two sides of MVP were designed. By using the FastDigest methylation-sensitive restriction enzyme (MSRE), DNA digestion, multiplex amplification, MCA detection and MCA profiles were performed in a single reaction tube. Same samples (peripheral venous blood, semen, and vaginal fluid, 5 samples each type) were tested by single-tube one step MVP and traditional MSRE-PCR MCA technology. To verify the feasibility of this method, the results were compared with that of the traditional technology. The MCA/HRM profiles of different samples were analyzed and compared. RESULTS: When the melting temperature of the fragments had a differential of 2 degrees C, the MCA melting peaks separated well, and MCA detection after multiplex amplification was successful. The single-tube PDP-MCA assay was developed, which integrated multiple reactions (digestion, amplification and detection) into one tube. By this method, the sample-specific profiles and data were analyzed in 2 h, which is similar to that of the traditional method. The rapid classifications of the samples were also realized. CONCLUSION: Multiplex MVPs can be analyzed in a single closed-tube. The single-tube PDP-MCA technology is a simple, fast, and automatable method. It can be used for detection of DNA methylation variations.

Trends in the Incidence of Vulvar and Vaginal Cancers With Different Histology by Race, Age, and Region in the United States (2001-2018).

Objectives: The race, age, and region-stratified incidence of vulvar (VUC) and vaginal (VAC) cancers with different histology were unclear. Methods: Data was retrieved from the United States Cancer Statistics database. Average annual percent change (AAPC) and incidence rate ratio (IRR) were calculated. Results: Overall, VUC incidence increased from 18.3 (per 1,000,000 woman-years) to 19.6, but VAC incidence decreased from 5.6 to 4.4. VUC squamous cell carcinoma (SCC) incidence increased (AAPC, 0.96; 95% CI, 0.66-1.25), VUC adenocarcinoma (ADE) incidence stabilized (AAPC, -0.24; 95% CI, -1.44 to 0.98), and VUC other malignancies (OM) incidence decreased (AAPC, -1.31; 95% CI, -2.58 to -0.02). While VAC incidence decreased for any histology (AAPC, -0.63; 95% CI, -1.03 to -0.22; AAPC, -1.60; 95% CI, -2.80 to -0.39; and AAPC, -1.57; 95% CI, -2.24 to -0.89 for SCC, ADE, and OM). Similar trends were observed in most of the stratifications. Conclusion: VUC and VAC incidences varied by histology overall and within stratifications by race, age, and region. The incidence decreased for VUC and VAC with all histologies, except for the increasing VUC SCC incidence.

Development and validation of models for predicting the overall survival and cancer-specific survival of patients with primary vaginal cancer: A population-based retrospective cohort study.

Background: No models have been developed to predict the survival probability for women with primary vaginal cancer (VC) due to VC's extreme rareness. We aimed to develop and validate models to predict the overall survival (OS) and cancer-specific survival (CSS) of VC patients. Methods: A population-based multicenter retrospective cohort study was carried out using the 2004-2018 Surveillance, Epidemiology, and End Results Program database in the United States. The final multivariate Cox model was identified using the Brier score and Harrell's C concordance statistic (C-statistic). The decision curve, calibration plot, and area under the time-dependent receiver operating characteristic curve (AUC) were used to evaluate model prediction performance. Multiple imputation followed by bootstrap was performed. Bootstrap validation covered the entire statistic procedure from model selection to baseline survival and coefficient calculation. Nomograms predicting OS and CSS were generated. Results: Of the 2,417 eligible patients, 1,692 and 725 were randomly allocated to the training and validation cohorts. The median age (Interquartile range) was 66 (56-78) and 65 (55-76) for the two cohorts, respectively. Our models had larger net benefits in predicting the survival of VC patients than the American Joint Committee on Cancer stage, presenting great discrimination ability and excellent agreement between the expected and observed events. The performance metrics of our models were calculated in three cohorts: the training cohort, complete cases of the validation cohort, and the imputed validation cohort. For the OS model in the three cohorts, the C-statistics were 0.761, 0.752, and 0.743. The slopes of the calibration plots were 1.017, 1.005, and 0.959. The 3- and 5-year AUCs were 0.795 and 0.810, 0.768 and 0.771, and 0.770 and 0.767, respectively. For the CSS model in the three cohorts, the C-statistics were 0.775, 0.758, and 0.755. The slopes were 1.021, 0.939, and 0.977. And the 3- and 5-year AUCs were 0.797 and 0.793, 0.786 and 0.788, and 0.757 and 0.757, respectively. Conclusion: We were the first to develop and validate exemplary survival prediction models for VC patients and generate corresponding nomograms that allow for individualized survival prediction and could assist clinicians in performing risk-adapted follow-up and treatment.

Radiotherapy Plus Chemotherapy Is Associated With Improved Survival Compared to Radiotherapy Alone in Patients With Primary Vaginal Carcinoma: A Retrospective SEER Study.

BACKGROUND: The efficacy of radiotherapy plus chemotherapy (RTCT) versus radiotherapy alone (RT) in the treatment of primary vaginal carcinoma has been controversial. We aimed to evaluate the up-to-date efficacy of RTCT on primary vaginal carcinoma in a real-world cohort. METHODS: We performed a retrospective analysis in patients with primary vaginal carcinoma retrieved from the Surveillance, Epidemiology, and End Results Program database from 2004 to 2016. Kaplan-Meier survival curves were plotted and compared by the log-rank test. Inverse probability weighting (IPW)-adjusted multivariate Cox proportional hazards and Fine-Gray competing-risk model was applied. RESULTS: Of the 1,813 qualified patients with primary vaginal carcinoma from 2004 to 2016, 1,137 underwent RTCT and 676 underwent RT. The median survival time was 34 months for the RT group and 63 months for the RTCT group. RTCT was significantly associated with improved overall survival (unadjusted HR = 0.71, 95% CI 0.62-0.82, p < 0.001; adjusted HR = 0.73, 95% CI 0.63-0.84, p < 0.001) and cancer-specific survival (unadjusted sHR = 0.81, 95% CI 0.69-0.95, p = 0.012; adjusted sHR = 0.81, 95% CI 0.69-0.96, p = 0.016). Age, histological type, tumor size, surgery, and FIGO stage were all independent prognostic factors for survival (p < 0.05 for all). Subgroup analysis demonstrated that RTCT was significantly associated with better survival in most subgroups, except for those with adenocarcinoma, tumor size <2 cm, or FIGO stage I. Moreover, sensitivity analysis did not alter the beneficial effects of RTCT. CONCLUSION: RTCT is significantly correlated with prolonged survival in patients with primary vaginal carcinoma. RTCT should be applied to most patients with primary vaginal carcinoma instead of RT alone, except for those with adenocarcinoma, tumor size <2 cm, or FIGO stage I.

Hepatic Resection Is Associated With Improved Long-Term Survival Compared to Radio-Frequency Ablation in Patients With Multifocal Hepatocellular Carcinoma.

Background: The prognosis of patients with hepatocellular carcinoma (HCC) is of major public health interest. However, studies comparing hepatic resection (HR) and radio-frequency ablation (RFA) applied to multifocal HCC are limited. This study aimed to compare the efficacies of HR and RFA in patients with multifocal HCC. Methods: We retrospectively analyzed a cohort from the Surveillance, Epidemiology, and End Results database between 2004 and 2015. Disease-specific survival and overall survival rates were assessed before and after propensity score matching (PSM). Results: In total, 2,201 patients with multifocal HCC treated with HR (n = 1,095) or RFA (n = 1,106) were included; 1,096 patients were identified after nearest-neighbor PSM at a ratio of 1:1 (HR: n = 548; RFA: n = 548). In the multivariate Cox regression model, HR was associated with significantly improved disease-specific survival [before PSM: hazard ratio 0.67, 95% confidence interval (CI) 0.57-0.79, p < 0.001; after PSM: hazard ratio 0.69, 95% CI 0.58-0.82, p < 0.001] and overall survival (before PSM: hazard ratio 0.67, 95% CI 0.58-0.78, p < 0.001; after PSM: hazard ratio 0.69, 95% CI 0.59-0.80, p < 0.001) compared to RFA in patients with multifocal HCC. In the survival curve analysis, the disease-specific survival of the HR group was similar to that of the RFA group before PSM (p = 0.936, log-rank test) but was significantly longer after PSM (p < 0.001) in all patients. Multivariate analyses revealed that differentiation grade, alpha-fetoprotein, tumor size, and tumor extension were independent predictors of poor prognosis in patients with multifocal HCC. Conclusions: The long-term survival rate of HR is better than that of RFA in patients with multifocal HCC. HR may serve as a first-line treatment for patients with multifocal HCC. The presence of large tumors and vascular invasion are not contraindications for HR.

Rigorous intensity and phase-shift manipulation in optical frequency conversion.

A simple method is employed to investigate the nonlinear frequency conversion in optical superlattices (OSL) with pump depletion. Four rigorous phase-matching conditions for different purposes are obtained directly from the nonlinear coupled equations, and the resulting OSL domain structures are generally aperiodic rather than periodic. With this method, not only the intensity but also the phase-shift of the harmonic waves can be manipulated at will. The second-harmonic generation of Gaussian beam is further investigated. This work may provide a guidance for the practical applications of designing nonlinear optical devices with high conversion efficiency.