321 research outputs found
The Pros and Cons of Prophylactic Central Compartment Lymph Node Dissection for Papillary Thyroid Carcinoma
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78140/1/thy.2009.1578.pd
Using Aerial Hyperspectral Remote Sensing Imagery to Estimate Corn Plant Stand Density
Since corn plant stand density is important for optimizing crop yield, several researchers have recently developed ground-based systems for automatic measurement of this crop growth parameter. Our objective was to use data from such a system to assess the potential for estimation of corn plant stand density using remote sensing images. Aerial hyperspectral remote sensing imagery was collected on three dates over three plots of corn in central Iowa during the 2004 growing season. The imagery had a spatial resolution of 1 m and a spectral resolution of 3 nm between 498 nm and 855 nm. A machine vision system for early-season measurement of corn plant stand density was also used to map every row of corn within the three plots, and a complete inventory of corn plants was generated as a rich ground reference dataset. A principal component regression analysis was used to assess relationships between plant stand density measurements and principal components of hyperspectral reflectance for each plot, on each image collection date, and at three different spatial resolutions (2, 6, and 10 m). The maximum R2 for regressions was 0.79. Estimates of corn plant stand density were best when using imagery collected at the later vegetative and early reproductive corn growth stages. Quantization effects due to row width complicated corn plant stand density estimates at 2 m spatial resolution, and better estimations were typically seen at resolutions of 6 m and 10 m. Among the different cases of plot, image date, and spatial resolution, the principal components of reflectance most highly correlated with plant stand density were able to be classified into four distinct types, denoted as types A, B, C, and D. Type A principal components contrasted all available visible red wavelengths with all available near-infrared wavelengths. Type B principal components contrasted green wavelengths (531 to 552 nm) plus shorter wave near-infrared (759 nm) with red wavelengths (675 to 693 nm) plus longer wave near-infrared (852 nm). Type C principal components summed green wavelengths (528 to 546 nm) and near-infrared wavelengths (717 to 855 nm). Type D principal components contrasted blue/green wavelengths (498 to 507 nm) with the red edge (717 nm). Remote sensing can be best used to estimate corn plant stand density at mid-season as long as plant stand variability exists and variability due to other factors is minimal
Expansion of Comprehensive Screening of Male Sexually Transmitted Infection Clinic Attendees with \u3cem\u3eMycoplasma genitalium\u3c/em\u3e and \u3cem\u3eTrichomonas vaginalis\u3c/em\u3e Molecular Assessment: a Retrospective Analysis
Of 1,493 encounters of males at a sexually transmitted infection (STI) clinic in a community with a high prevalence of STI, Chlamydia trachomatis was detected in 8.7% and Neisseria gonorrhoeae was detected in 6.6%. Additional Trichomonas vaginalis and Mycoplasma genitalium screening found 17.4% and 23.9% of the encounters, respectively, to be positive for STI. STI agents were detected in 13.7% of urine specimens; addition of pharyngeal and rectal collections to the analysis resulted in detection of STI agents in 19.0% and 23.9% of encounters, respectively. A total of 101 (23.8%) encounters of identified STI involved sole detection of M. genitalium. Expansion of the STI analyte panel (including M. genitalium) and additional specimen source sampling within a comprehensive STI screening program increase identification of male STI carriers
A multi-institutional study evaluating and describing atypical parathyroid tumors discovered after parathyroidectomy
Objective: To describe common intraoperative and pathologic findings of atypical parathyroid tumors (APTs) and evaluate clinical outcomes in patients undergoing parathyroidectomy.
Methods: In this multi-institutional retrospective case series, data were collected from patients who underwent parathyroidectomy from 2000 to 2018 from three tertiary care institutions. APTs were defined according to the AJCC eighth edition guidelines and retrospective chart review was performed to evaluate the incidence of recurrent laryngeal nerve injury, recurrence of disease, and disease-specific mortality.
Results: Twenty-eight patients were identified with a histopathologic diagnosis of atypical tumor. Mean age was 56 years (range, 23-83) and 68% (19/28) were female. All patients had an initial diagnosis of primary hyperparathyroidism with 21% (6/28) exhibiting clinical loss of bone density and 32% (9/28) presenting with nephrolithiasis or renal dysfunction. Intraoperatively, 29% (8/28) required thyroid lobectomy, 29% (8/28) had gross adherence to adjacent structures and 46% (13/28) had RLN adherence. The most common pathologic finding was fibrosis 46% (13/28). Postoperative complications include RLN paresis/paralysis in 14% (4/28) and hungry bone syndrome in 7% (2/28). No patients with a diagnosis of atypical tumor developed recurrent disease, however there was one patient that had persistent disease and hypercalcemia that is being observed. There were 96% (27/28) patients alive at last follow-up, with one death unrelated to disease.
Conclusion: Despite the new AJCC categorization of atypical tumors staged as Tis, we observed no recurrence of disease after resection and no disease-specific mortality. However, patients with atypical tumors may be at increased risk for recurrent laryngeal nerve injury and incomplete resection
All Weather Calibration of Wide Field Optical and NIR Surveys
The science goals for ground-based large-area surveys, such as the Dark
Energy Survey, Pan-STARRS, and the Large Synoptic Survey Telescope, require
calibration of broadband photometry that is stable in time and uniform over the
sky to precisions of a per cent or better. This performance will need to be
achieved with data taken over the course of many years, and often in less than
ideal conditions. This paper describes a strategy to achieve precise internal
calibration of imaging survey data taken in less than photometric conditions,
and reports results of an observational study of the techniques needed to
implement this strategy. We find that images of celestial fields used in this
case study with stellar densities of order one per arcmin-squared and taken
through cloudless skies can be calibrated with relative precision of 0.5 per
cent (reproducibility). We report measurements of spatial structure functions
of cloud absorption observed over a range of atmospheric conditions, and find
it possible to achieve photometric measurements that are reproducible to 1 per
cent in images that were taken through cloud layers that transmit as little as
25 per cent of the incident optical flux (1.5 magnitudes of extinction). We
find, however, that photometric precision below 1 per cent is impeded by the
thinnest detectable cloud layers. We comment on implications of these results
for the observing strategies of future surveys.Comment: Accepted for publication in The Astronomical Journal (AJ
Consensus Statement on the Terminology and Classification of Central Neck Dissection for Thyroid Cancer
Background: The primary goals of this interdisciplinary consensus statement are to review the relevant anatomy of the central neck compartment, to identify the nodal subgroups within the central compartment commonly involved in thyroid cancer, and to define a consistent terminology relevant to the central compartment neck dissection. Summary: The most commonly involved central lymph nodes in thyroid carcinoma are the prelaryngeal (Delphian), pretracheal, and the right and left paratracheal nodal basins. A central neck dissection includes comprehensive, compartment-oriented removal of the prelaryngeal and pretracheal nodes and at least one paratracheal lymph node basin. A designation should be made as to whether a unilateral or bilateral dissection is performed and on which side (left or right) in unilateral cases. Lymph node plucking or berry picking implies removal only of the clinically involved nodes rather than a complete nodal group within the compartment and is not recommended. A therapeutic central compartment neck dissection implies that nodal metastasis is apparent clinically (preoperatively or intraoperatively) or by imaging (clinically N1a). A prophylactic/elective central compartment dissection implies nodal metastasis is not detected clinically or by imaging (clinically N0). Conclusion: Central neck dissection at a minimum should consist of removal of the prelaryngeal, pretracheal, and paratracheal lymph nodes. The description of a central neck dissection should include both the indication (therapeutic vs. prophylactic/elective) and the extent of the dissection (unilateral or bilateral).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78103/1/thy.2009.0159.pd
Constraining bacterial production, conversion efficiency and respiration in the Ross
Abstract Bacteria consume dissolved organic carbon at rates averaging about 50% of primary production across a wide spectrum of marine ecosystems. However, total utilization rates are poorly constrained due to a lack of data on conversion eciencies and/or bacterial respiration rates. We estimated total community dark respiration rates (DCR) from in vitro oxygen utilization and estimated bacterial production from H-leucine incorporation during January}February 1997 in the Ross Sea, Antarctica. Bacterial respiration rates (BR) were estimated by assuming that BR was less than some fraction of DCR, and by choosing values for the bacterial growth eciency. By comparing these derived bacterial respiration rates with the DCR we were able to constrain conversion eciencies had to be in the range of 35}45%, similar to independent discrete measurements made during the summer season on this cruise. Dark respiration rates are an absolute constraint on the estimates of bacterial carbon demand. A low value of the leucine conversion factor (1.5 kgC mol\) was required to meet this strong constraint
Prognosis of Differentiated Thyroid Cancer in Relation to Serum Thyrotropin and Thyroglobulin Antibody Status at Time of Diagnosis
BACKGROUND: Serum thyrotropin (TSH) concentration and thyroid autoimmunity may be of prognostic importance in differentiated thyroid cancer (DTC). Preoperative serum TSH level has been associated with higher DTC stage in cross-sectional studies; data are contradictory on the significance of thyroid autoimmunity at the time of diagnosis.
OBJECTIVE: We sought to assess whether preoperative serum TSH and perioperative antithyroglobulin antibodies (TgAb) were associated with thyroid cancer stage and outcome in DTC patients followed by the National Thyroid Cancer Treatment Cooperative Study, a large multicenter thyroid cancer registry.
METHODS: Patients registered after 1996 with available preoperative serum TSH (n=617; the TSH cohort) or perioperative TgAb status (n=1770; the TgAb cohort) were analyzed for tumor stage, persistent disease, recurrence, and overall survival (OS; median follow-up, 5.5 years). Parametric tests assessed log-transformed TSH, and categorical variables were tested with chi square. Disease-free survival (DFS) and OS was assessed with Cox models.
RESULTS: Geometric mean serum TSH levels were higher in patients with higher-stage disease (Stage III/IV=1.48 vs. 1.02 mU/L for Stages I/II; p=0.006). The relationship persisted in those aged ≥45 years after adjusting for sex (p=0.01). Gross extrathyroidal extension (p=0.03) and presence of cervical lymph node metastases (p=0.003) were also significantly associated with higher serum TSH. Disease recurrence and all-cause mortality occurred in 37 and 38 TSH cohort patients respectively, which limited the power for survival analysis. Positive TgAb was associated with lower stage on univariate analysis (positive TgAb in 23.4% vs. 17.8% of Stage I/II vs. III/IV patients, respectively; p=0.01), although the relationship lost significance when adjusting for age and sex (p=0.34). Perioperative TgAb was not an independent predictor of DFS (hazard ratio=1.12 [95% confidence interval=0.74-1.69]) or OS (hazard ratio=0.98 [95% confidence interval=0.56-1.72]).
CONCLUSIONS: Preoperative serum TSH level is associated with higher DTC stage, gross extrathyroidal extension, and neck node metastases. Perioperative TgAb is not an independent predictor of DTC prognosis. A larger cohort is required to assess whether preoperative serum TSH level predicts recurrence or mortality
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