56 research outputs found

    Hydroa vacciniforme lymphoproliferative disorder:a case report

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    In this study, we report a case of hydroa vacciniforme lymphoproliferative disorder (HVLPD). The patient, who was 21 years old at the time of initial consultation,suffering from recurrent papules, vesicular rashes, bleeding and black scabs on the neck, face and trunk. Serum EBV-DNA was significantly increased (2.88×107 copies/mL). The patient underwent skin biopsies twice within 2 years. The pathology of the first skin biopsy showed partial degeneration and loosening of the epidermal stratum spinosum, intraepidermal blister formation, partial epidermal detachment, and multifocal small abscesses seen in the blisters and stratum spinosum. Patchy infiltration of small lymphocytes, plasma cells, histiocytes, and eosinophils in the dermis, with no significant atypia of lymphocytes, EBER in situ hybridization was negative, which made it difficult to make a definitive diagnosis on pathology. The pathology of the second skin biopsy showed blisters visible within the patient's epidermis, and atypical lymphoid cells infiltrate around the hair follicles, sweat glands and blood vessels in the dermis. The immunohistochemical analysis indicated that lymphoid cells were positive for CD3, CD5, CD4, CD8, granzyme B and TIA-1, while CD56 and Perforin were negative, and the proliferation rate of Ki-67 was approximately 10%. EBER was positive by in situ hybridization consistent with clinicopathologic features of HVLPD. More than 1 year after receiving symptomatic treatment, the patient's rash worsened, with sometimes fever and left eyelid edema. The third skin biopsy performed in the other hospital showed that atypical lymphoid cells infiltrated the subcutaneous adipose tissue, and the proliferation rate of Ki-67 was 60%. The disease progressed to EBER-positive T-cell lymphoma. After 2 courses of chemotherapy with gemcitabine, cisplatin, dexamethasone and pegaspargase, the patient's edema subsided and the rash healed. This report demonstrates the clinical and pathologic features of the disease during its evolution and progression, with a view to enriching its diagnostic and therapeutic experience

    Timing Determination of Invasive Fungal Infection Prophylaxis According to Immune Function in HSCT Patients

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    Patients who receive a hematopoietic stem cell transplantation (HSCT) exhibit an immune defect after recovering from neutropenia. The current guidelines do not recommend fungal prophylaxis in these patients, except for grades III to IV GVHD in HSCT. Thus, the timing for the initiation and cessation of IFI prophylaxis in immune-compromised patients remains a challenging endeavor. We retrospectively analyzed patients who received auto or allo-HSCT and monitored their immune function after recovering from neutropenia by measuring the levels of IgG, IgA, IgM, as well as the number of T, B, NK cells. We found that the level of IgG and NK cell count exhibited a significant difference with the incidence of IFI by logistic regression (p = 0.000 vs. 0.000, respectively) and conditional logistic regression (p = 0.009 vs. p = 0.002). The initiation of IFI prophylaxis was determined to be IgG < 7 mg/mL and NK cell count < 6.5 × 104/mL by an receiver operating characteristic curve separately. Tests in parallel increased the test sensitivity and specificity. Thus, the optimal timing for initiating prophylaxis in patients after HSCT could be IgG < 7 mg/mL or NK cell count < 6.5 × 104/mL. Future large-scale prospective clinical trials are required to verify these findings. Patients who are immuno-compromised after auto or allo-HSCT may benefit from a lower fungi infection incidence with immune surveillance and proper fungal prophylaxis

    Application of a simultaneous iterations reconstruction technique for a 3-D water vapor tomography system

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    The simultaneous iterations reconstruction technique (SIRT) is one of several reconstruction algorithms of the ART family. It is used widely in tomography because of its convenience in dealing with large sparse matrices. Its theoretical background and iteration model are discussed at the beginning of this paper. Then, the implementation of the SIRT to reconstruct the three-dimensional distribution of water vapor by simulation is discussed. The results show that the SIRT can function effectively in water vapor tomography, obtain rapid convergence, and be implemented more easily than inversion

    Estimation of GLONASS Code Inter-frequency Biases with Multiple Parameters Based on a Single Station and Its Impact on Combined Precise Point Positioning

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    The disadvantages of ignoring GLONASS receiver code inter-frequency biases(IFBs) in GPS/GLONASS combined precise point positioning (PPP) are analysed in this contribution. A new algorithm of combined PPP and code IFBs estimation based on "multiple parameters" is proposed where inter-system bias parameter is merged with code IFB. Multiple independent inter-system and inter-frequency bias (ISFB) parameters are introduced to the observation equations which could compensate the GLONASS code IFBs in the function model. In the meantime, the GLONASS code IFBs can be estimated precisely based on a single station. GPS/GLONASS observation data from 30 IGS sites which involves 6 different GNSS receiver manufacturers is processed with the proposed algorithm. The results show that the GLONASS code IFBs could be several meters and a significant correlation exists between code IFB and signal frequency. It seems to be difficult to provide a priori code IFB precisely with simple function model. GLONASS code IFBs with the same receiver manufacturer mostly show similar characteristics, however, abnormal behaviors are also found in some receivers. It is worth to note that GLONASS code IFBs could be quite different with two receivers even if their receiver types, firmware versions and antenna types are all the same. The PPP results demonstrate that the new algorithm can significantly accelerate the convergence of combined PPP by compensating the GLONASS code IFBs efficiently. The combined PPP accuracy of "multiple parameters" method is comparable with that of traditional "single parameter" method and almost unaffected by freedom reduction of the function model

    Analysis of Seismic Deformation from Global Three-Decade GNSS Displacements: Implications for a Three-Dimensional Earth GNSS Velocity Field

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    With the rapid development of Global Navigation Satellite System (GNSS) technology, the long-term accumulated GNSS observations of global reference stations have provided valuable data for geodesy and geodynamics studies since the 1990s. Acquiring the precise velocity of GNSS stations is very important for the study of global plate movement, crustal deformation, etc. However, the seismic activities nearby some GNSS observation stations may seriously change the station’s motion trajectory. Therefore, our research was motivated to propose a method allowing for station seismic deformation, and apply it to construct an updated global GNSS velocity field. The main contributions of this work included the following. Firstly, we improved the GNSS data processing procedures and seismic data selection strategies to obtain GNSS coordinate time series with mm-level precision (3–5 and 6–8 mm in the horizontal and vertical, respectively) and information of each site impacted by seismic events, which provides necessary input data for further analysis. Secondly, an Integrated Time Series Method (ITSM) concerning the effect of seismic deformation was proposed to model the station’s nonlinear motion accurately. Distinguished with existing studies, all parameters including seismic relaxation time can be simultaneously estimated by ITSM, which improves the accuracy and reliability of GNSS station velocity significantly. Thirdly, to optimize the ITSM-based model, the influences of seismic relaxation time (a. 0.1 × true, b. 10 × true, c. true), parameterization mode (a. Offset + Velocity, b. Offset + Velocity + PSD, c. Offset + Velocity + PSD + Period), and the Post-Seismic Deformation (PSD) model (a. None, b. Exp, c. Log, d. Exp + Log) on results of GNSS time series analyzing were discussed. The results showed that the fitting accuracy of GNSS displacements was better than 5 mm and 10 mm in the horizontal and vertical, respectively. Finally, the global GNSS station velocity field (referred to as GGV2020 hereafter) was refined by ITSM using global GNSS observations and seismic data during 1990–2020. This not only helps interpret plate tectonic motion, establish and maintain a Dynamic Terrestrial Reference Frame (DTRF) but also contributes to better investigating geodynamic processes. GGV2020 results showed that the accuracy of global velocity was better than 1 mm/a, and the averages of Root Mean Square Error (RMSE) were 0.19 mm/a, 0.19 mm/a, and 0.33 mm/a in the north, east, and up direction, respectively. Besides, the RMSE obeys normal distribution. Compared with ITRF2014, there was a difference of about 1–2 mm/a between them due to differences in terms of observation span, processing model, and geodetic technology. Moreover, GGV2020 is expected to enrich and update the existing velocity field products to describe the characteristics of regional crustal movement in more detail, especially in Antarctica

    Analysis and combination of four technique-individual EOP time series

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    Based on four intra-technique combined solutions in SINEX format, we tried at first to assess the accuracy of each single-technique Earth Orientation Parameters (EOPs) series over a past time interval of at least15 years by comparison with IERS EOP 08C04 combined solution as the reference in this paper. The EOPs studied here mainly consist of four elements, i.e. polar motion (XPO, YPO), Universal Time (UT1-UTC) and length-of-day (LOD). We combined these intra-technique EOP series, each of them associated with a given space geodetic technique by taking advantage of the relationship of the first three EOP components and three rotational parameters which carry the orientation of technique-related reference frame with respect to the estimated weekly inter-technique combined reference frame. Results indicated that the discrepancy between the pole coordinates (XPO, YPO) series, extracted from the intra-SLR combined loose-constraint solutions and the IERS EOP 08C04, seemed to be clearly characterized by systematic errors. Although both the XPO and YPO series determined by intra-VLBI combination had no significant characteristic of system error, they had relatively large difference values at some point with respect to the IERS EOP 08C04, which may be limited by the quantity of observation stations. Since the number of GPS stations is on the increase aimed at better global coverage, the accuracy of pole coordinates provided by IGS was superior to that derived from other space-geodetic techniques. As for DORIS XPO and YPO series from intra-DORIS combined minimal-constraint solutions, the discrepancy range of the former with respect to IERS EOP 08C04 was a little smaller than that of the latter. The objective of this study is twofold: on the one hand to analysis individual EOP series derived from the various space-geodetic techniques, on the other hand to present the new inter-technique combined EOP solution consistent with weekly inter-technique combined reference frame. Keywords: Earth Orientation Parameter (EOP), Inter-technique combination, Terrestrial reference fram

    Preprocessing of GPS Coordinate Sequence Based on Singular Spectrum Analysis

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    Abstract Since it is inevitable existence of unknown mutation signals, gross error and data missing in the GPS station coordinates, while the nonlinear signals and misalignment are also neglected by means of piecewise linear detection, thus a novel algorithm called jump determination scheme, which is based on singular spectrum analysis (SSA), is proposed here. The results of real data analysis and simulation tests indicate that the SSA-based pre-processing method has properly detected the gross error and recovered the missing data. Meanwhile, owing to taking into account the correlation in the position time series, it can effectively avoid the influence of gross error on the accurate determination of each uncertain jump. In addition, it can retain the intrinsic characteristics in station coordinates, which has vital significance for the gross error detection and missing data recovery. By this new method, even if the missing rate of data reaches 10% or more, we can eliminate the gross error and then obtain complete data with an accuracy of better than 5 mm and 1 cm for the horizontal components and the height component, respectively
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