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Crack issues afflicting a building integrated photovoltaics (BIPV) system are major concerns in terms of the system’s maintenance and power degradation. Although there may be many circumstances that bring about cracks in BIPV modules during the installation process, identifying the degradation of PV module efficiency resulting from the effects of cracks tends to be a very difficult task unless actual indoor or outdoor tests or detailed electroluminescence imaging tests are conducted. Many current studies have demonstrated that cracks may or may not impact the output performance of PV modules depending on the damage levels or where the damage is located. For BIPV applications such as replacement for building materials, there is still a lack of information and case studies addressing crack issues in a quantitative manner for evaluating BIPV output performance. Therefore, the objectives of this study are to investigate the effects of cracks in BIPV modules on power outputs and to identify detailed relationships between the cracks and power output based on experimental and simulated analysis. An experimental facility located in Daejeon, South Korea, was used to gather data from cracked and non-cracked BIPV modules. By using the field-measured data and facility’ information, a simulation model was developed using SolarPro software, and a simulated-based analysis was conducted to evaluate the impact of cracks in BIPV modules on output values after proper validation of the model. The results from this study reveal that cracks in BIPV modules exhibit significant degradation in BIPV modules’ outputs of up to 43% reduction during the experimental period. From the annual comparative results, output degradations of 34.6–35.4% were estimated when the BIPV modules included cracks. As a result, the cracks in the BIPV modules could be carefully addressed as issues occurring in the BIPV installation process.

The performance of the Operable Building Integrated Photovoltaic (OBIPV) system applied to the building envelope to reduce the building energy consumption varies significantly depending on the operation method and influence of the surrounding environment. Therefore, optimization through performance monitoring is necessary to maximize power generation of the system. This study used temperature-corrected normalized efficiency (NE*) to evaluate the power generation performance of the operation methods and predict that of the OBIPV system based upon the measured data. It was confirmed that power generation performance decreased when the photovoltaic (PV) operation angle changed, the system remaining the same. A decrease in power generation performance due to partial shading from an overhang was also observed. As a result of the power generation prediction for two months using NE*, the error of the measured values was found to be less than 3%. In addition, with or without any partial shading of the OBIPV system, its performance degradation was predicted with an annual electricity generation decrease by 36 kWh/yr (6.5%). Therefore, NE* can be used as an indicator for evaluating the power generation performance of PV systems, and to predict generation performance considering partial shading.

The application of a building-integrated photovoltaic (BIPV) module to an elevation means that the factors causing performance losses in a BIPV are relatively high compared to a photovoltaic (PV) that is installed at the optimal angle. Therefore, it is essential to evaluate the performance loss factors of BIPV and to examine the characteristics of each performance loss factor. Measured data were used to analyze the performance and loss factors (module temperature, dust and soiling, power conditioning system (PCS) standby mode, direct current–alternating current (DC-AC) conversion loss). A performance ratio of International Electrotechnical Commission (IEC) 61724 was used to power the generation performance analysis. The impact analysis of each loss factor is analyzed by using difference of the power generation, the module efficiency, irradiation, and the performance ratio according to the existence of a loss factor. The performance ratio analysis result of this BIPV system shows a range of 66.8–69.5%. The range of performance loss due to each loss factor was as follows; module temperature: 2.2–6.0%, dust and soiling: 2.2–23.1%, PCS standby loss: 4.9–15.7%, DC–AC conversion loss: 4.1–8.0%. Because the effects of the loss factors are different depending on the installation conditions, the performance loss of the system should be minimized by taking this into consideration in the design stage in the BIPV.

(1) Background: The application of high insulation to a building envelope helps reduce the heating load, but increases the cooling load. Evaluating the installation of high insulation glazing to buildings in climate zones with four distinct seasons, as in the case of South Korea, is very important; (2) Methods: This study compared the heating energy performance of four types of glazing, inside vacuum double glazing, outside vacuum double glazing, single vacuum glazing, and low-e double glazing, with fixed low-e coating positions on the inside of the room in a mock-up chamber under the same conditions. The annual energy consumption according to the building type was analyzed using a simulation; (3) Results: As the insulation performance of building envelopes has increased, the energy saving rate of inside vacuum double glazing has been increased further in office buildings. In residential buildings, the energy saving rate of inside vacuum double glazing with a low SHGC (solar heat gain coefficient) has become higher than that of outside vacuum double glazing; (4) Conclusions: Since the effects of SHGC on the energy saving rates are greater in high insulation buildings, SHGC should be considered carefully when selecting glazing in climate zones with distinct winter and summer seasons.

The extent of thyroid surgery for patients with low- and interm ediate-risk differentiated thyroid carcinoma (DTC), with a primary tumour <4 cm and no ext rathyroidal extension (ETE) or lymph node (LN) metastases, has shifted in a more cons ervative direction. However, clinicopathological risk factors, including microscopic ETE, aggressive histology, vascular invasion in papillary thyroid carcinoma (PTC) and intermediate volume of LN metastases, can only be identified after completing thyroid lobectomy. It is controversial whether patients with these risk factors should immediately undergo complete thyroidectomy and/or radioactive iodine remnant ablation or should be monitored without further treatments. Data are conflicting about the prognostic impact of these risk factors on clinical DTC outcomes. Notably, the recurrence rate in patients who underwent thyroid lobectomy is low and the few recurrences that develop during longterm follow-up can readily be detected by neck ultrasonography and treated by salvage surgery with no impact on survival. These findings suggest that a more conservative approach may be a preferred management strategy over immediate completion surgery, despite a slightly higher risk of structural recurrence. Regarding follow-up of postlobectomy DTC patients, it is reasonable that an initial risk s tratification system based on clinicohistological findings be used to guide the short-term follow-up prior to evaluating the response to initial therapy and that the dynamic risk strat ification system based on the response to initial therapy be used to guide long-term foll ow-up. [ABSTRACT FROM AUTHOR]

Objective: Papillary thyroid microcarcinoma (PTMC) accounts for most of the increase in thyroid cancer in recent decades. We compared clinical outcomes and surgical complications of lobectomy and total thyroidectomy (TT) in PTMC patients. Design and methods: In this retrospective individual risk factor-matched cohort study, 2031 patients with PTMC were initially included. Patients who underwent lobectomy or TT were one-to-one matched according to individual risk factors, including age, sex, primary tumor size, extrathyroidal extension, multifocality and cervical lymph node (LN) metastasis. Results: In total, 688 patients were assigned to each group. During the median 8.5 years of follow-up, 26 patients (3.8%) in the lobectomy group and 11 patients (1.6%) in the TT group had recurrences. The relative risk of recurrence was significantly less in the TT than that in the lobectomy group (hazard ratio (HR) 0.41; 95% confidence interval (CI) 0.21-0.81; P = 0.01). Most recurrences (84.6%) in the lobectomy group occurred in the contralateral lobe, and all patients were disease-free after completion of thyroidectomy. There were no significant differences in recurrencefree survival between the two groups after exclusion of contralateral lobe recurrences (HR, 2.75; 95% CI, 0.08-8.79; P = 0.08). There were significantly more patients with transient and permanent hypoparathyroidism in the TT than that in the lobectomy group (P < 0.001). Conclusions: Lobectomy could be appropriate for most patients with PTMC when there is no evidence of extrathyroidal disease in the preoperative work-up. Preoperative and postoperative imaging studies are important for patients who undergo lobectomy for PTMC, because most recurrences are in the contralateral lobe. [ABSTRACT FROM AUTHOR]

Ectopic adrenocorticotropic hormone (ACTH) syndrome is caused most frequently by a bronchial carcinoid tumor or by small cell lung cancer. Medullary thyroid carcinoma (MTC) is a rare etiology of ectopic ACTH syndrome. We describe a case of Cushing syndrome due to ectopic ACTH production from MTC in a 48-year-old male. He was diagnosed with MTC 14 years ago and underwent total thyroidectomy, cervical lymph node dissection and a series of metastasectomies. MTC was confirmed by the pathological examination of the thyroid and metastatic mediastinal lymph node tissues. Two years after his last surgery, he developed Cushingoid features, such as moon face and central obesity, accompanied by uncontrolled hypertension and new-onset diabetes. The laboratory results were compatible with ectopic ACTH syndrome. A bilateral adrenalectomy improved the clinical and laboratory findings that were associated with Cushing syndrome. This is the first confirmed case of ectopic ACTH syndrome caused by MTC in Korea. [ABSTRACT FROM AUTHOR]

Objective: The presence of central neck lymph node (LN) metastases (defined as pN1a according to Tumor Node Metastasis classification) in papillary thyroid cancer (PTC) is known as an independent risk factor for recurrence. Extent of LN metastasis and the completeness of removal of metastatic LN must have an impact on prognosis but they are not easy to measure. Moreover, the significance of the size of metastatic tumors in LNs has not been clarified. This study was to evaluate the impact of the extent of LN metastasis and size of metastatic tumors on the recurrence in pathological N1a PTC. Design: This retrospective observational cohort study enrolled 292 PTC patients who underwent total thyroidectomy with central neck dissection from 1999 to 2005. LN ratio was defined as the number of metastatic LNs divided by the number of removed LNs, which was regarded as variable reflecting both extent of LN metastasis and completeness of resection, and LN size as the maximal diameter of tumor in metastatic LN. Results: The significant risk factors for recurrence in univariate analysis were large primary tumor size (defined as larger than 2 cm), high LN ratio (defined as higher than 0.4), and presence of macrometastasis (defined as larger than 0.2 cm). Age, sex, clinical node status, and microscopic perithyroidal extension had no effect on recurrence. In multivariate analysis, high LN ratio and presence of macrometastasis were independent risk factors for recurrence. Conclusion: LN ratio and size of metastatic nodes had a significant prognostic value in pathological N1a PTC. We suggest that risk stratification of pathological N1a PTC according to the pattern of LN metastasis such as LN ratio and size would give valuable information to clinicians. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the clinical outcomes of persistent radioiodine uptake (RAIU) in the neck by diagnostic whole body scan (DxWBS) after initial therapy and the efficacy of the second ablation in patients with differentiated thyroid carcinoma (DTC). Design Patients with DTC who underwent bilateral surgery and high-dose remnant ablation between 2000 and 2004 were included. Patients with elevated serum stimulated thyroglobulin (sTg) or extensive lateral neck lymph node involvement at initial surgery underwent a second ablation, and patients with undetectable sTg or in very low-risk groups were observed. Results Among 572 patients, 25 had persistent RAIU in the neck at first DxWBS. After a median 65·7 months of follow-up, five of these patients (20%) had persistent disease, whereas another 20 patients had no abnormal findings by ultrasonography (US) or other imaging modalities. Seven of 20 patients underwent second ablation and 13 were observed. RAIU disappeared spontaneously in about half of the patients in the observation group. There were no significant between-group differences in change of RAIU at follow-up DxWBS ( P = 0·62). Serum sTg decreased and eventually disappeared over a few years in both groups. Ablation failure was not an independent risk factor for recurrence ( P = 0·169). Conclusions Neck US and serum sTg, but not DxWBS, were useful diagnostic tools during follow-up of patients with persistent uptake in the neck at DxWBS. A second ablation was not necessary when neck US showed no evidence of disease, especially in patients with very low sTg concentration. [ABSTRACT FROM AUTHOR]

Background Surgery for metachronous adrenal metastases from solid primary carcinoma has increased with the development of technical skills. Here we analyzed the postoperative clinical outcomes of patients who underwent adrenalectomy for metachronous adrenal metastases from solid primary carcinomas. Methods Patients who underwent adrenalectomy for metachronous adrenal metastases after initial treatment of primary carcinoma at Asan Medical Center from 2000 to 2010 were included. Clinicopathological parameters were analyzed to evaluate prognostic outcomes. Results A total of 30 patients with 19 hepatocellular carcinomas and 11 lung carcinomas were included. The mean age was 54.3 years. The mean time until adrenalectomy was 23 months. The size of the metastatic adrenal tumor and the disease status of the primary carcinoma at the time of adrenalectomy were associated with second recurrence after adrenalectomy (P < 0.05). There was no significant difference in disease-specific recurrence-free survival between patients who underwent open adrenalectomy and laparoscopic adrenalectomy (P = 0.646). Conclusions Surgical treatment should be recommended for metachronous adrenal metastases in patients with no evidence of primary carcinoma and/or in those having metastatic adrenal tumors ≤4.4 cm. This approach may increase the recurrence-free interval related to second recurrence. Further, laparoscopic adrenalectomy appears sufficient for the treatment of such patients. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the learning curve of robotic thyroid surgery with regard to both operation time and temporary hypoparathyroidism using quantitative statistical analysis. A total of 194 patients who underwent total thyroidectomy and concomitant central compartment node dissection for papillary thyroid carcinoma by a single surgeon between December 2008 and September 2017 were enrolled. The learning curve for operation time was assessed using the cumulative sum (CUSUM) technique, and the number of procedures required to reduce the incidence of temporary hypoparathyroidism to less than 30% was determined using the CUSUM and risk-adjusted CUSUM (RA-CUSUM) techniques. The learning curve for operation time was divided into three phases: phase 1 (the initial learning period, 1st–19th cases), phase 2 (the challenging period, 20th–121st cases), and phase 3 (the competent phase, 122nd–194th cases). To reduce the incidence of temporary hypoparathyroidism to

Turner syndrome has multiple comorbidities such as osteoporosis, obesity, diabetes, hypothyroidism, and hypertension. As they are treatable conditions in Turner syndrome, early recognition and proper treatment should be needed. We report on a 23-year-old woman with Turner syndrome who presented with severe osteoporosis and hypercalcemia. Laboratory tests showed elevated levels of serum calcium and parathyroid hormone. Dual-energy X-ray absorptiometry showed severe osteopo-rosis (z score, -3.5). Ultrasound and 99mTc scintigraphy of parathyroid glands showed an adenoma in the right inferior gland. She was diagnosed with primary hyperparathyroidism due to an adenoma of the parathyroid gland. After excision of the adenoma, the patient's serum calcium and parathyroid hormone levels returned to normal. Although only a few cases of Turners syndrome with primary hyperparathyroidism have been reported, hyperparathyroidism should be considered in cases of Turner syndrome with severe osteoporosis and hypercalcemia.

The aim of this study was to evaluate the oncologic safety of robot thyroid surgery compared to open thyroid surgery for papillary thyroid carcinoma (PTC). We enrolled 722 patients with PTC who underwent a total thyroidectomy with central compartment node dissection (CCND) from January 2009 to December 2010. These patients were classified into open thyroid surgery (n = 610) or robot thyroid surgery (n = 112) groups. We verified the impact of robot thyroid surgery on clinical recurrence and ablation/control-stimulated thyroglobulin (sTg) levels predictive of non-recurrence using weighted logistic regression models with inverse probability of treatment weighting (IPTW). Age, sex, thyroid weight, extent of CCND, and TNM were significantly different between the two groups (p < 0.05); however, there was no significant difference in recurrence between the open and robot groups (1.5% vs. 2.7%; p = 0.608). The proportion of patients with ablation sTg < 10.0 ng/mL and control sTg < 1.0 ng/mL was comparable between the two groups (p > 0.05). Logistic regression with IPTW using the propensity scores estimated by adjusting all of the parameters demonstrated that robot thyroid surgery did not influence the clinical recurrence (OR; 0.784, 95% CI; 0.150-3.403, p = 0.750), ablation sTg (OR; 0.950, 95% CI; 0.361-2.399, p = 0.914), and control sTg levels (OR; 0.498, 95% CI; 0.190-1.189, p = 0.130). Robot thyroid surgery is comparable to open thyroid surgery with regard to oncologic safety in PTC patients.

BACKGROUND:Although patients with minimally invasive follicular thyroid carcinoma (MIFTC) generally have an excellent prognosis, distant metastasis occurs in some patients. Risk factors for distant metastasis have been reported, none has been found to be conclusive. This study evaluated risk factors for distant metastasis, including protein markers, in patients with MIFTC. METHODS:A review of patient records identified 259 patients who underwent surgery at Asan Medical Center from 1996 to 2010 and were subsequently diagnosed with MIFTC. After review of pathological slides, 120 patients with paraffin blocks suited for tissue microarrays (TMA) were included in this study. Immunohistochemical stain of TMA slides was performed by protein markers; β-catenin, C-MET, CK19, estrogen receptor (ER) α, ER β, HBME-1, MMP2, PPAR γ and progesterone receptor. RESULTS:120 patients included 28 males (23.3%) and 92 females (76.7%), of mean age 41.5±10.8 years (range, 13-74 years). Eight patients (6.7%) had distant metastases during follow-up. Univariate analysis showed that age (≥45 years), male sex, and extensive vascular invasion (≥4 foci) were associated with distant metastasis. Multivariate regression analysis showed that extensive vascular invasion was the only independent risk factor for distant metastasis (p = 0.012). Although no protein markers on TMA analysis were directly related to distant metastasis of MIFTC, CK19 expression was more frequent in patients with than without extensive vascular invasion (p = 0.036). CONCLUSION:Extensive vascular invasion was the only independent risk factor for distant metastasis of MIFTC. No proteins markers were directly related to distant metastasis, but CK19 was associated with extensive vascular invasion.

BACKGROUND:The follicular variant of papillary thyroid cancer (FVPTC), especially the encapsulated non-invasive subtype, is a controversial entity. Recent study suggested using 'non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP)' for these indolent carcinomas. We evaluated the impact of reclassification from non-invasive encapsulated FVPTCs (EFVPTCs) to NIFTPs in the diagnosis of thyroid nodules with architectural atypia. METHODS:We reviewed 1301 thyroid nodules with architectural atypia in core needle biopsy (CNB) specimens obtained from March 2012 to February 2013. Nodules were classified into atypia of undetermined significance with architectural atypia (AUS-A, 984, 76%) or follicular neoplasm/suspicious for a follicular neoplasm (FN/SFN, 317, 24%). Among them, diagnostic surgery was performed in 384 nodules (30%). RESULTS:In total, 160 nodules (42%) presented final malignant diagnoses including 39 non-invasive encapsulated FVPTCs (10%). The malignancy rate was estimated to be 7-35% in AUS-A nodules and 28-49% in FN/SFN nodules. After reclassification, the malignancy rate was much decreased and estimated to be 5-24% in AUS-A nodules, and 23-39% in FN/SFN nodules. Thyroid nodules with final malignant diagnoses were significantly more likely to have a FN/SFN CNB diagnosis, malignant US features and concomitant nuclear atypia in CNB specimens. However, these factors could not differentiate NIFTPs from other malignancies. CONCLUSIONS:After reclassification of non-invasive EFVPTCs to NIFTPs, the malignancy rate of thyroid nodules with architectural atypia in CNB specimens was decreased. However, there were no preoperative factors differentiating other malignancies from NIFTPs. The presence of malignant US features or concomitant nuclear atypia might help clinicians deciding diagnostic surgery but, these features also might indicate NIFTPs.

BACKGROUND:Lateral cervical lymph node (LCLN) metastasis, or pathologic N1b disease, is an important risk factor in papillary thyroid carcinoma (PTC). However, many patients have favorable prognosis even with pathologic N1b patients in clinical practice. The study aims to identify high- and intermediate-risk groups based on initial pathologic characteristics in these patients. PATIENTS:This study included 518 classical PTC patients confirmed as pathologic N1b at initial surgery between 2001 and 2010. All patients underwent a single fixed activity (5.6 GBq) of radioactive I-131 remnant ablation. RESULTS:Patients with a primary tumor larger than 4 cm, gross extrathyroidal extension, metastatic LN larger than 3 cm, or greater than 10 metastatic LCLN were classified as high-risk group. These comprehensive pathologic criteria were retrieved from cox proportional hazard models. Twenty two percent of patients (n = 113) were classified as high-risk and 78% (n = 405) as intermediate-risk group. Successful ablation was identified in only 32% of the patients in the high-risk group and 61% in the intermediate-risk group (p < 0.001). The difference between the two risk groups was independent to gender. There was a significant difference in disease-free survival between the high- and intermediate- risk N1b groups during 5.1 years of median follow-up (84% vs. 59%, p < 0.001). Distant metastasis was more prevalent in the high-risk group (20%) than in the intermediate-risk group (4%, p < 0.001). CONCLUSIONS:The prognosis of PTC patients with LCLN metastasis varies depending on initial pathologic characteristics. We proposed the comprehensive pathologic criteria for sub-classification of N1b into high- and intermediate-risk groups and this sub-classification may permit personalized management of N1b PTC patients.

To determine the clinicopathological risk factors and reliable biochemical predictors of the development of hypocalcemic symptoms after total thyroidectomy on the basis of serum calcium and intact parathyroid hormone (PTH) levels measured 1 hour after surgery, a prospective study was performed on 817 patients who underwent a total thyroidectomy with central compartment node dissection (CCND) due to well-differentiated thyroid cancer. We evaluated the correlations between hypocalcemic symptom development and clinicopathological factors. And the predictability for hypocalcemic symptom development of intact PTH cut-offs (

The present study compared the long-term outcome of subtotal thyroidectomy (ST) to that of total thyroidectomy (TT) in Graves’ disease (GD). Patients with GD requiring surgery were divided between two groups: ST and TT. Postoperative thyroid function (PoTF) changes, including hypothyroidism, euthyroidism, and hyperthyroidism, and surgical complications were analyzed 3 months and 2 years after surgery. During the study period, 350 GD patients underwent surgery, of whom 254 underwent ST and 96 underwent TT. In the ST group, the rates of hypothyroidism, euthyroidism, and hyperthyroidism were 92.5%, 6.7%, and 0.4%, respectively, after 3 months, and 86.1%, 8.6%, and 5.3%, respectively, after 2 years. No difference in the rate of surgical complication was observed between the ST and TT groups (p=0.089). Most of the ST patients showed hypothyroidism after surgery, and euthyroidism was rare. The long-term outcome of ST included noticeable PoTF changes and recurrence of GD. These results suggest that TT should be considered as a treatment option in GD requiring surgery.