Quantifying surface roughness on UO2 fuel pellets using optical techniques.

Rapid, non-destructive nuclear forensic techniques can aid in signature development and provide valuable information for provenance assessments. Using optical profilometry and digital microscopy, we studied the surface roughness of fuel pellets to probe its usefulness as a forensic signature and its relationship to a given producer's grinding techniques. Arithmetic average areal (Sa) surface roughness measurements provide a rapid, non-destructive technique, producing efficient measurements with smaller standard uncertainties relative to 2D, arithmetic average profile (Ra) surface roughness measurements. Digital microscopy proved to be the superior technique over optical profilometry, in part due to its higher image quality, faster data acquisition capabilities, and multi-purpose potential in physical surface characterization. Using digital microscopy, fuel pellet Sa surface roughness varies in commercial reactor fuel pellets from 1.54±0.17µm to 2.11±0.12µm and does not appear to depend solely on the use of wet versus dry grinding techniques. Populations of pellets produced at three different commercial reactor fuel production facilities were distinguishable on the basis of Sa. Complementary to other key forensic characteristics, such as dimensions and enrichment, Sa measurements provide a promising nuclear forensic signature for sintered UO2 fuel pellets.

Parathyroidectomy for Patients With Primary Hyperparathyroidism and Associations With Hypertension.

Importance: Hyperparathyroidism is associated with cardiovascular disease. However, evidence for a beneficial consequence of parathyroidectomy on hypertension is limited. Objective: To investigate if parathyroidectomy improves hypertension in patients with primary hyperparathyroidism (PHPT). Design, Setting, and Participants: In this cohort study and retrospective database review, patients with PHPT and hypertension between January 1, 2008, and December 31, 2016, were identified. The mean arterial pressure (MAP) and number of antihypertensive medications were compared between those who did and did not undergo parathyroidectomy. The setting was a large health care system. Primary hyperparathyroidism was defined using biochemical data, and hypertension was identified by International Classification of Diseases, Ninth Revision codes. Exposure: Parathyroidectomy was identified in the database by Current Procedural Terminology codes. Main Outcomes and Measures: The MAP and use of antihypertensive medications were compared for patients who underwent parathyroidectomy and those who did not at 6 months, 1 year, and 2 years. Multivariable logistic regression was used to assess the adjusted odds ratios for both increased and decreased use of antihypertensive medications. Results: In this cohort study of 2380 participants (79.0% female), patients undergoing parathyroidectomy (n = 501) were younger (mean [SD] age, 65.3 [9.7] vs 71.9 [10.4] years; P < .001) and took fewer antihypertensive medications at baseline (mean [SD] number of medications, 1.2 [1.1] vs 1.5 [1.3], P < .001) than nonsurgical patients (n = 1879). Patients with parathyroidectomy showed greater improvement in their MAP at all follow-up time points (the median [SD] MAP change from baseline to 1 year was 0.1 [8.7] mm Hg without parathyroidectomy vs -1.2 [7.7] mm Hg after parathyroidectomy, P = .002). Nonsurgical patients were more likely vs those with parathyroidectomy to require more antihypertensive medications at 6 months (15.9% [n = 298] vs 9.8% [n = 49], P = .001), 1 year (18.1% [n = 340] vs 10.8% [n = 54], P < .001), and 2 years (17.6% [n = 330] vs 12.2% [n = 61], P = .004). By multivariable analysis, parathyroidectomy was independently associated with freedom from an increased number of antihypertensive medications at all periods (eg, adjusted odds ratio, 0.49; 95% CI, 0.34-0.70; P < .001 at 1 year). Among patients who were initially not taking antihypertensive medications, patients with parathyroidectomy were less likely vs no surgery to start antihypertensive medication treatment at all periods (eg, 10.2% [13 of 127] vs 30.4% [136 of 447], P < .001 at 1 year). Conclusions and Relevance: This study's findings suggest that, among hypertensive patients with PHPT, parathyroidectomy may be associated not only with greater decreases in their MAP but also with reduced requirements for antihypertensive medications. Parathyroidectomy decreased the number of patients who began taking antihypertensive medications. Additional study will be required to find whether there are downstream cardiovascular benefits of parathyroidectomy. Preexisting hypertension, particularly in those not already taking antihypertensive medications, should be considered when weighing surgical treatment.

Calcium-Facilitated Aggregation and Precipitation of the Uranyl Peroxide Nanocluster U60 in the Presence of Na-Montmorillonite.

The unique and diverse features of uranyl peroxide nanoclusters may contribute to the enhanced mobility of uranium in the environment. This study examines the sorption of the uranyl peroxide nanocluster [UO2(O2)(OH)]6060- (U60) to Na-montmorillonite (SWy-2), plagioclase (anorthite), and quartz (SiO2) as a function of time, U60 concentration, and mineral concentration. SWy-2 was studied in both its untreated form as well as after two different pretreatments, denoted as partially treated SWy-2 and fully treated SWy-2. U60 was removed (∼99%) from solution in the presence of untreated and partially treated SWy-2. However, U60 was not removed from suspensions containing anorthite, quartz, or fully treated SWy-2, even after several months. The removal of U60 from suspensions containing untreated SWy-2 is promoted in part by the exchange of Li+ counter-ions, normally weakly associated with U60 in solution, for Ca2+ ions naturally present in the clay. In solution, Ca2+ ions induce the aggregation of nanoclusters, which precipitate on the surface of SWy-2. Ca-rich U60 aggregates associated with SWy-2 were identified and characterized by scanning electron microscopy with energy dispersive spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. This research enhances our understanding of the molecular-scale processes controlling U60 behavior at the mineral-water interface.

Preferential Use of Total Thyroidectomy without Prophylactic Central Lymph Node Dissection for Early-Stage Papillary Thyroid Cancer: Oncologic Outcomes in an Integrated Health Plan.

CONTEXT: The oncologic benefit of prophylactic central lymph node dissection (pCLND) in node-negative papillary thyroid cancer has been debated. OBJECTIVE: To determine the use of pCLND in an integrated health care system and to evaluate recurrence in the cohort. DESIGN: Retrospective cohort study of patients with clinically node-negative papillary thyroid cancer who underwent total thyroidectomy with or without pCLND in Kaiser Permanente Southern California Region hospitals between January 1996 and December 2008. Chart review of all patients was performed to collect demographic data, tumor features, stage, and recurrences. MAIN OUTCOME MEASURES: Proportion undergoing pCLND and recurrence rate of papillary thyroid cancer. RESULTS: There were 864 patients identified (mean age, 46.1 years). Almost all patients had total thyroidectomy alone, and 34 (3.9%) underwent pCLND. The TNM (tumor, node, metastasis) stages for the 2 groups were not significantly different (p = 0.18). Overall recurrence was 24 (2.8%). There were 23 (2.8%) recurrences in the no-pCLND group and 1 (2.9%) recurrence in the pCLND group (p = 0.95). The rate of recurrence in the central neck compartment in those without pCLND was 1.1% and 0% in the pCLND group (p = 0.54). The recurrence rate in the lateral neck compartment in the no-pCLND group was 2.2%, and this rate was 2.9% in the pCLND group (p = 0.76). The no-pCLND group had a recurrence-free survival rate of 96.4% at 10 years vs 96.8% in the pCLND patients (p = 0.80). CONCLUSION: Presently, routine pCLND is difficult to advocate in our medical system.

The Mount Sinai clinical pathway for the management of pheochromocytoma.

OBJECTIVE: Pheochromocytomas are complex tumors that require a comprehensive and systematic management plan orchestrated by a multidisciplinary team. METHODS: To achieve these ends, The Mount Sinai Adrenal Center hosted an interdisciplinary retreat where experts in adrenal disorders assembled with the aim of developing a clinical pathway for the management of pheochromocytomas. RESULTS: The result was a consensus for the diagnosis, perioperative management, and postoperative management of pheochromocytomas, with specific recommendations from our team of adrenal experts, as well as a review of the current literature. CONCLUSION: Our clinical pathway can be applied by other institutions directly or may serve as a guide for institution-specific management.

Hypothyroidism after hemithyroidectomy.

BACKGROUND: The risk of hypothyroidism after hemithyroidectomy is variable, and most estimates come from single institutional studies. The purpose of the present study was to determine the incidence of hypothyroidism at the population level, and to evaluate predictive factors for hypothyroidism after hemithyroidectomy. METHODS: This retrospective study identified euthyroid patients who underwent hemithyroidectomy between 2000 and 2010 for benign disease in Kaiser Permanente Southern California regional hospitals. The incidence of hypothyroidism [thyroid stimulating hormone (TSH) levels >4 µIU/ml] was analyzed. The independent effect of age-quartile, gender, race, thyroiditis, and preoperative TSH level on the development of hypothyroidism was evaluated. RESULTS: Of 1,240 euthyroid patients identified, 417 (34 %) developed hypothyroidism, and 314 (25 % of total group) needed levothyroxine. Hypothyroidism was more common in age-quartile 2 (32 %), age-quartile 3 (37 %), and age-quartile 4 (42 %) than in age-quartile 1 (25 %) [adjusted odds ratio (OR) = 1.87; 95 % confidence interval (CI) 1.27-2.76, p = 0.002; age-quartile 4 compared to age-quartile 1]. Hypothyroidism was more frequent with increasing preoperative TSH levels 36, 72, and 92 % in patients with TSH levels of 1.0-2, 2.01-3, and 3.01-4 µIU/ml, respectively, compared to 17 % in those with TSH levels <1 µIU/ml [adjusted OR = 45.1; 95 % CI 13.5-151, p < 0.0001; 3.01-4 µIU/ml compared to <1 µIU/ml]. Thyroiditis was also an independent predictor of hypothyroidism. CONCLUSIONS: About one third of euthyroid patients who undergo hemithyroidectomy develop hypothyroidism. The most significant predictor is the preoperative TSH level, with an approximate doubling of risk for each 1 unit of TSH increase over 1 µIU/ml. Our categorical scale is simple and allows for easy recall when counseling patients preoperatively.

Ultrasound measurements in hypertrophic pyloric stenosis: don't let the numbers fool you.

BACKGROUND: Ultrasound guidelines for hypertrophic pyloric stenosis (HPS) have fixed minimum measurements and do not account for variation in patient weight or age. We sought to determine if preoperative pyloric measurements correlated with weight and age in patients with surgically proven HPS. METHODS: A retrospective analysis was conducted of 189 patients with HPS treated at a single institution over a 5-year period (2005 to 2010). Pearson correlation and linear regression analyses were used to determine if there were statistically significant associations between these combinations of factors: age and pyloric muscle thickness, weight and pyloric muscle thickness, age and pyloric length, and weight and pyloric length. RESULTS: Patients' mean age was 4.6 weeks (range, 1 to 17 weeks). Their mean weight was 3.9 kg (range, 2.5 to 8.0 kg). Mean pyloric muscle thickness was 0.42 cm (range, 0.18 to 0.86 cm), and mean pyloric length was 1.89 cm (range, 0.8 to 2.8 cm). Pearson correlation coefficient analysis showed a significant relationship between age and muscle thickness (r = 0.35, p < 0.001) as well as weight and muscle thickness (r = 0.24, p = 0.001). No significant relationship existed between pyloric length and age or weight. Linear regression analysis demonstrated similar results. CONCLUSION: In patients with HPS, pyloric muscle thickness was directly related to age and weight. Practitioners should be aware that smaller and younger infants with a clinical diagnosis of HPS may still truly have HPS even though the minimum diagnostic criterion for muscle thickness or length is not found on ultrasound.

Bilobed fibula flap for reconstruction of through-and-through oromandibular defects.

BACKGROUND: The role of fibula free flaps for reconstruction of through-and-through oromandibular defects is examined. METHODS: Thirty-four patients underwent reconstruction of through-and-through oromandibular defects using fibula free flaps that contain large, bilobed skin paddles for simultaneous reconstruction of intraoral mucosa and external skin. We examined the incidence of wound healing complications, the need for revision reconstructive surgery, and factors affecting the incidence of complications. RESULTS: Wound healing complications occurred in 50% of patients. There was a relatively high incidence of partial flap necrosis (26%) and revision surgery (41%). The area of the flap skin paddle was significantly associated with the risk of partial flap necrosis and the need for revision surgery. CONCLUSIONS: Many through-and-through oromandibular defects can be successfully reconstructed using a fibula free flap that contains a large, bilobed skin paddle. However, wound healing complications are increased when the flap skin paddle area exceeds 300 cm2.