Screening of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is one of head and neck cancer. It has a complicated etiology involving Epstein–Barr virus (EBV) infection, environment changes, and genetic susceptibility. Early symptoms of NPC are unspecific, so most NPC patients are diagnosed at a late stage. An effective population screening strategy could increase the early detection and early diagnosis rate. As far, serological detection of EBV antibodies such as VCA-IgA, EA-IgA, and EBNA1-IgA, are widely used in NPC mass screening; EBV DNA load detection in plasma or nasopharyngeal swab was applied to screen in endemic populations for assessing the feasibility. However, the current screening schemes still have disadvantages such as lowly positive predictive value, unclear effectiveness of screening and cost-effectiveness. In the present chapter, we try to review the different screening strategies for NPC to understand the future direction of development

Thermal Error Modeling of the CNC Machine Tool Based on Data Fusion Method of Kalman Filter

This paper presents a modeling methodology for the thermal error of machine tool. The temperatures predicted by modified lumped-mass method and the temperatures measured by sensors are fused by the data fusion method of Kalman filter. The fused temperatures, instead of the measured temperatures used in traditional methods, are applied to predict the thermal error. The genetic algorithm is implemented to optimize the parameters in modified lumped-mass method and the covariances in Kalman filter. The simulations indicate that the proposed method performs much better compared with the traditional method of MRA, in terms of prediction accuracy and robustness under a variety of operating conditions. A compensation system is developed based on the controlling system of Siemens 840D. Validated by the compensation experiment, the thermal error after compensation has been reduced dramatically

Comparison of Different Risk-Stratification Systems for the Diagnosis of Benign and Malignant Thyroid Nodules

Introduction: To compare the efficacy of four different ultrasound-based risk-stratification systems in assessing the malignancy risk of thyroid nodules in the Chinese population.Methods: We retrospectively reviewed the digital ultrasound images of 1,568 patients (1,612 thyroid nodules) who underwent surgery in our hospital between January 2012 and December 2017. All thyroid nodules were pathologically identified as malignant or benign. We evaluated the following ultrasound characteristics: size, location, composition, echogenicity, shape, margins, calcification or echogenic foci, and extrathyroidal extension. Each nodule was categorized using four risk-stratification systems: the American Thyroid Association (ATA) classification, the Thyroid Imaging, Reporting, and Data System (TIRADS) of the American College of Radiology (ACR-TIRADS), the European Thyroid Association TIRADS (EU-TIRADS), and the TIRADS developed by Kwak et al. (Kwak-TIRADS). The diagnostic performance of each risk-stratification system relative to the pathological results was analyzed. We used receiver operating characteristic curves to identify cutoff values that yielded optimal sensitivity (SEN), specificity (SPE), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC).Results: Of the 1,612 nodules, 839 (52.0%) were benign, and 773 (48.0%) were malignant. The AUCs of the ACR-TIRADS, EU-TIRADS, Kwak-TIRADS, and ATA classification were 0.879, 0.872, 0.896, and 0.869, respectively. The Kwak-TIRADS had the best SEN, NPV, ACC, and AUC, while the ACR-TIRADS had the best SPE and PPV.Conclusion: All four risk-stratification systems had good diagnostic performances (AUCs > 86%). Considering its high SEN, NPV, ACC, and AUC, we believe that the Kwak-TIRADS may be the more effective risk-stratification system in the Chinese population

Analysis of Serum Levels of IgA Antibodies to Epstein Barr Virus Capsid Antigens in the Spouses and the Children of Patients with Nasopharyngeal Carcinoma

OBJECTIVE To analyze the serum levels of IgA antibodies to Epstein Barr virus capsid antigens (EBV/IgA/VCA) in patients with nasopharyngeal carcinoma (NPC) and in their spouses and children in order to further evaluate the risk of developing the disease in family members of NPC patients. METHODS Four categories of sera were used to detect EBV/ IgA/VCA using the immunoenzyme method. In our study 317 biopsy-con fi rmed NPC patients, 317 spouses and 317 children of the NPC patients, as well as 413 healthy subjects as the controls that came from the same area were enrolled. RESULTS The positive rate of EBV/IgA/VCA was 97.2%, 14.2%, 19.9% and 3.1% in the NPC patients, the spouse and child groups, and in the control group, respectively. The positive rate was significantly higher in the NPC group than in the other 3 groups, and it was also significantly higher in the spouse and in the child groups than in the control group (P < 0.001). The results of the relative to identified distribution unit (Ridit) analysis showed that the average Ridit values were 0.860, 0.404, 0.424 and 0.356 respectively in the NPC patients, in the spouse and child groups, and in the control group. The antibody titer of IgA/VCA was significantly higher in the NPC group than in the other 3 groups, and it was also signifi cantly higher in both the spouse and child groups than in the control group (P < 0.001). The OR values of positive EBV/IgA/VCA antibody were 5.09 and 7.63, respectively in the spouse and child groups. No significant differences were found in the positive rates or in the titers of IgA/VCA antibody between the groups of spouses and children (P > 0.05). CONCLUSION Positive detection of EBV/IgA/VCA antibody occurs in familial aggregation, as there is ample opportunity for EBV reactivation in the spouses and in the children of NPC patients. These individuals with a high risk of developing the NPC should be closely followed in order to detect the disease at an early stage

Small-signal stability analysis of photovoltaic generation connected to weak AC grid

Abstract A small-signal model of photovoltaic (PV) generation connected to weak AC grid is established based on a detailed model of the structure and connection of a PV generation system. An eigenvalue analysis is then employed to study the stability of PV generation for different grid strengths and control parameters in a phase-locked loop (PLL) controller in the voltage source converter. The transfer function of the power control loop in the dq rotation frame is developed to reveal the influence mechanism of PLL gains on the small-signal stability of PV generation. The results can be summarized as follows: ① oscillation phenomena at a frequency of about 5 Hz may occur when the grid strength is low; ② the tuning control parameters of the PLL have a noticeable effect on the damping characteristics of the system, and larger proportional gain can improve the system damping;③ within a frequency range of 4-5 Hz, the PLL controller has positive feedback on the power loop of PV generation. A virtual inductance control strategy is proposed to improve the operational stability of PV generation. Finally, a simulation model of PV generation connected to weak AC grid is built in PSCAD/EMTDC and the simulation results are used to validate the analysis

The Correlation between Volatile Compounds Emitted from Sitophilus granarius (L.) and Its Electrophysiological and Behavioral Responses

The granary weevil Sitophilus granarius (L.) is one of the most serious primary insect pests of stored products. When S. granarius present in grains, various volatile organic compounds are released as chemical signals which can be used to detect the insects. In this study, volatile chemical compounds released from S. granarius were analyzed using the headspace solid phase micro-extraction (HS-SPME) coupled with gas chromatography (GC)&ndash;mass spectrometry (MS) techniques. Two key compounds, 3-hydroxy-2-butanone and 1-pentadecene, were identified from mixed gender of S. granarius adults at high density. Moreover, both male and female adults showed dose-dependent electroantennography (EAG) responses to 3-hydroxy-2-butanone. In behavioral assays, S. granarius was attracted to 3-hydroxy-2-butanone at 0.001 &micro;g/10 &micro;L but repelled at 10 &micro;g/10 &micro;L or higher. S. granarius was consistently repelled by 1-pentadecene at concentrations at 0.001 and 1000 &micro;g/10 &micro;L. 3-hydroxy-2-butanone and 1-pentadecene have considerable potential to offer in the development of new approaches for the monitoring and management of this destructive stored grain insect pest

Identification of Biomarker Volatile Organic Compounds Released by Three Stored-Grain Insect Pests in Wheat

Monitoring and early detection of stored-grain insect infestation is essential to implement timely and effective pest management decisions to protect stored grains. We report a reliable analytical procedure based on headspace solid-phase microextraction coupled with gas chromatography&ndash;mass spectrometry (HS-SPME-GC-MS) to assess stored-grain infestation through the detection of volatile compounds emitted by insects. Four different fibre coatings were assessed; 85 &micro;m CAR/PDMS had optimal efficiency in the extraction of analytes from wheat. The headspace profiles of volatile compounds produced by Tribolium castaneum (Herbst), Rhyzopertha dominica (Fabricius), and Sitophilus granarius (Linnaeus), either alone or with wheat, were compared with those of non-infested wheat grains. Qualitative analysis of chromatograms showed the presence of different volatile compound profiles in wheat with pest infestation compared with the wheat controls. Wheat-specific and insect-specific volatile compounds were identified, including the aggregation pheromones, dominicalure-1 and dominicalure-2, from R. dominica, and benzoquinones homologs from T. castaneum. For the first time, the presence of 3-hydroxy-2-butanone was reported from S. granarius, which might function as an alarm pheromone. These identified candidate biomarker compounds can be utilized in insect surveillance and monitoring in stored grain to safeguard our grain products in future