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Robotic surgical systems enable surgeons to perform precise movement in the surgical field using high-resolution 3D vision and flexible robotic instruments. We aimed to evaluate the feasibility and safety of performing axillary lymph node dissection using a robotic surgical system in patients with node-positive breast cancer.Thirty-two women with breast cancer who underwent robot-assisted nipple-sparing mastectomy (RNSM) and level I/II axillary lymph node dissection were analyzed. Patients were divided into two groups: RNSM with conventional axillary lymph node dissection (CALND) vs. RNSM with robotic axillary lymph node dissection (RALND). Clinicopathological features and surgical outcomes were analyzed.The median age of the patients was 44 (range 20-59) years. Eleven patients underwent RALND. None of the clinicopathologic features differed between the two groups. There were no statistically significant differences in surgical outcomes, except for the final incision size, between the two groups. The proportion of cases with an incision ≤ 40 mm was 63.6% in the RALND group and 36.4% in the CALND group (p = 0.020).RALND can be safely performed in RNSM. RNSM with RALND is comparable to RNSM with CALND in terms of early surgical outcomes. The incision size can be reduced when using RALND.

Introduction: More than half of the results of axillary lymph node dissection followed by metastasis in sentinel lymph node(SLN) biopsy are negative. For deescalating axillary surgery, it is necessary to predict the non-SLN metastasis state, where metastasis was confirmed in the SLN biopsy. Method: Breast cancer patients with T1 and T2 stage were retrospectively reviewed from January 2008 to December 2016. A total of 818 patients underwent surgery as the primary treatment and the result of SLN biopsy was positive for metastasis. Patients who skipped SLN biopsy procedure and were proven metastatic axillary lymph nodes by needle-aspiration biopsy (NAB) were excluded. SLN was defined as lymph nodes detected by the dual method with hot-uptake by radioisotope and dyed by blue dye, or lymph nodes with palpable or suspected metastatic findings during SLN biopsy. Clinicopathological factors including and extra-nodal invasiveness were analyzed. Result: The median follow-up period was 73 months. Non-SLN metastasis was significantly seen in patients with older than 50 years, positive node metastases by preoperative NAB, high T stage, and extra-nodal invasion. In subgroup analysis, patients who underwent total mastectomy had the similar patterns of the increased risk of having non-SLN. Poor overall survival was observed in the patients with the presence of non-SLN metastasis. Conclusion: We confirmed predictive factors with a high probability of non-SLN metastasis. Axillary lymph node dissection cannot be overlooked in the patients proven the metastatic result of preoperative NAB. Citation Format: Jee Hyun Ahn, Suk Jun Lee, Jieon Go, Hyung Seok Park, Jee Ye Kim, Seung Il Kim, Byeong Woo Park, Seho Park. The clinical impact of preoperatively needle-aspiration biopsy for axillary lymph nodes in T1-T2 breast cancer patients with axillary lymph node metastasis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-05-56.

Backgroud Since the results of TAILORx trial were published, it was shown that premenopausal young patients with intermediate Oncotype Dx(ODx) recurrence score(RS) (16-25) may benefit from adjuvant chemotherapy. In secondary analysis of the TAILORx trial, clinicopathological features can provide complementary information in addition to Oncotype Dx results. Although ambiguous benefit of adjuvant chemotherapy in premenopausal women with intermediate risk makes clinical decision difficult, the baseline characteristic may vary depending on menopausal status. This study intends to analyze whether the intermediate-risk group shows differences in characteristics by menopausal status. Materials and Methods 760 early breast cancer patients with ER positive, HER2 negative and lymph node negative patients who have been tested ODx from July 2013 to December 2020 at Severance Hospital were retrospectively reviewed. Results Of the 760 patients, 262 patients were postmenopausal status and 498 patients were premenopausal status. Among 262 postmenopausal patients, 152 patients were in low-risk group(RS 0-20), 43 patients were in intermediate-risk group(RS 21-25), 67 patients were in high-risk group(RS 26-100). Among 498 patients, 353 patients were in low-risk group(RS 0-20), 75 patients were in intermediate-risk group(RS 21-25), 70 patients were in high-risk group(RS 26-100), respectively. In premenopausal patients with intermediate risk, clinical risk group, PR score, and Ki-67 showed a significant difference from the low risk group(p-value 0.003, Citation Format: Jung Min Park, Jee Hyun Ahn, Soon Bo Choi, Jieon Ko, Jee Ye Kim, Hyung Seok Park, Seung Il Kim, Byeong-Woo Park, Seho Park. Distinctive clinicopathological features of premenopausal women with intermediate 21-gene recurrence score [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-11-13.

Background: Achieving pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) is known important for predicting survival. However, few studies have reported prognosis of minimal residual disease. In this study, we evaluated the long term survival of the patients with breast or nodal pCR and compare patients with minimal residual disease to the breast and node pCR group. As it is difficult to analyze residual cancer burden and tumor-infiltrating lymphocytes in the retrospective study, we assessed the residual tumor or nodal status according to the pathologic report after surgery based on the AJCC 8th edition staging system. Methods: This study retrospectively reviewed 753 patients who achieved pCR of breast or node after NAC from 2010 to 2017 at Severance Hospital. We divided patients into five groups based on the residual disease; breast and node pCR (ypT0/TisN0), minimal residual disease (ypT1mi/T1aN0, ypT0/TisN0i+/N1+), breast-only pCR (ypT0/TisN1+), node-only pCR with residual tumor size no larger than 20mm (ypT1b/T1cN0), and node-only pCR with residual tumor size larger than 20mm (ypT2+N0). The basic characteristics and the 10-year event free survival (EFS) were evaluated. EFS was defined as time from surgery to last follow-up date without any events. Results: We analyzed the data until May 26, 2021, and 50.2% (n=378) of the patients achieved breast and node pCR. Minimal residual disease, defined as residual tumor size no larger than 5mm and residual nodal size 2mm, included 126 patients (16.7%). Overall, there was significant difference in 10-year EFS among five groups (ypT0/TisN0; 94.7%, ypT1mi/T1aN0, ypT0/TisN0i+/N1+; 93.7%, ypT1b/T1cN0; 86.8%, ypT0/TisN1+; 87.9%, ypT2+N0; 71.9%, p Citation Format: Jieon Go, Jee Hyun Ahn, Jung Min Park, Soon Bo Choi, Jee Ye Kim, Hyung Seok Park, Seung Il Kim, Byeong-Woo Park, Seho Park. Long-term prognosis of minimal residual disease in breast cancer patients with breast or nodal pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-07-14.

Background: Ki67 has been studied a lot as a prognostic factor, but ambiguity exists as a value of a prognostic factor that conforms to the guideline due to analytical and methodological issues. However, Ki67 is still represented as IHC representing proliferation, and it is evaluated as an important prognostic factor in many studies. Recently, the international Ki67 in breast cancer working group (IKWG) suggested that in early breast cancer with Estrogen receptor positive (ER+) and HER2 negative (HER2-), Ki67 5% or less could predict a good prognosis and 30% or more could predict a bad prognosis. However, the reality and limitation is that it is still difficult to predict the prognosis at Ki67 5% to 30%. The aim of our study intends to identify that if Progestrone receptor (PR) information is added to Ki67, which has such an ambiguous section, it can give additional prognostic information. Methods: We selected 2668 patients with early breast cancer who underwent surgery and were pathologically diagnosed with ER+ and HER2-. We divided these patients into three groups by Ki67 30%. PR was divided into low and high based on 20%. In each of the three groups, multivariate analysis was performed to identify whether PR is an important factor in prognosis. We set the Ki67 cutoff to 15% in the 5%≤Ki67≤30% group. In this group, we made three combinations of Ki67 and PR with Low group (Ki-6730%. Multivariate analysis was performed in total patients, and hazard ratio(HR) of Ki67 30% was 1, 2.978, and 6.203, respectively, and also it was statistically significant (p=0.004). In the clinical risk (combination of T size, N status, and Histologic grade), HR of clinical high was significantly higher than clinical low (HR: Clinical low : Clinical high = 1: 2.234, p20%, which was statistically significant (HR: PR >20 : PR ≤20% = 1: 1.550, p=0.016). Multivariate analysis was performed for each of the three groups. In the Ki67 30% groups, PR had no statistical significance, but in 5%≤ Ki67 ≤30%, PR was statistically significant (HR: PR >20% vs PR ≤20% = 1 vs 1.613, p= 0.029). In the multivariate analysis of 5%≤ Ki67 ≤30% performed with the Ki67/PR combination, HR of Low, intermediated, and high was 1, 2.139, and 2,054, respectively, and also it was statistically significant (p=0.003, and 0.030). Conclusion: Ki67 can be used as a single prognostic value in at least 30% of early breast cancer with ER+ and HER2-. In the case of 5% ≤Ki67≤ 30%, additional prognostic prediction is possible with the combination of Ki67 and PR. Keywords: Ki67, Progesterone receptor, Prognosis, Estrogen receptor positive, HER2 negative, Early breast cancer Citation Format: Soon Bo Choi, Jung Min Park, Jee Hyun Ahn, Jieon Go, Jeeye Kim, Hyung Seok Park, Seung Il Kim, Byeong-Woo Park, Seho Park. The prognostic significance of Ki67 and progesterone receptor; could they really have prognostic importance in early breast cancer with estrogen receptor positive, HER-2 negative? [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-08-13.

Background: Adjuvant endocrine therapy against hormone receptor for more than 5 years has a better prognosis in a subset of patients with hormone receptor-positive breast cancer. The Clinical Treatment Score post-5 years(CTS5) is well known as a promising tool to predict survival outcomes such as distant recurrence after 5-years adjuvant endocrine therapy. The purpose of this study was to determine whether CTS5 is sufficiently relevant to predict the effectiveness of extended endocrine therapy. Method: 3193 breast cancer patients treated between January 2001 and December 2014 were reviewed. The extracted patients were free from disease recurrence or death for 5 years after surgical treatment. The duration of prior adjuvant endocrine therapy was defined as 4.5 to 5.5 years with patients receiving anti-hormonal agents. We investigated the risk of disease-free survival(DFS) and overall survival(OS) according to the premenopausal(age≤50) and postmenopausal(age>50) status, and additionally applied three CTS5 risk groups (low-risk 3.86) to predict the prognosis. Result: The median follow-up period was 8.1(4.5-15.5) years. For total patients, CTS5 showed a distinct division of survival outcomes according to risk groups (p Citation Format: Jee Hyun Ahn, Jung Min Park, Soon Bo Choi, Jieon Go, Jee Ye Kim, Hyung Seok Park, Seung Il Kim, Byeong-Woo Park, Seho Park. Clinical treatment score post-5 years (CTS5) and the prediction of survival benefit from extended endocrine therapy for breast cancer patients under and over 50 years of age [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-07-03.

Purpose This study aimed to identify the association between Ki-67 level and the prognosis of patients with breast cancer, regardless of the timing of Ki-67 testing (using preoperative biopsy vs. postoperative specimen). Methods A total of 4177 patients underwent surgery between January 2008 and December 2016. Immunohistochemical Ki-67 levels, using either preoperative (1673) or postoperative (2831) specimens, were divided into four groups using cutoff points of 10%, 15%, and 20%. Results Groups with higher-Ki-67 levels, in both the pre- and postoperative periods, showed significantly larger tumor size, higher grade, more frequent hormone receptor-negativity and human epidermal growth factor receptor 2 overexpression, and active adjuvant treatments than groups with lower-Ki-67 levels. High-Ki-67 levels were also significantly associated with poor survival, irrespective of the timing of specimen examination. Conclusion Despite the problems associated with Ki-67, Ki-67 level is an important independent prognostic factor, regardless of the timing of Ki-67 testing, i.e., preoperative or postoperative testing.

Background: Axillary evaluation is unnecessary for pure ductal carcinoma in situ (DCIS); however, it is performed because of upstaging risks. Purpose of this study is to decrease the upstaging rate to invasive cancer and unnecessary axillary evaluation in patients with preoperative DCIS. Methods: We reviewed patients with preoperative DCIS who underwent breast-conserving surgery (BCS) with IOF biopsy. Positive Intra-operative frozen section (IOF) biopsy findings were defined as the presence of invasive or micro-invasive cancer. The IOF biopsy and permanent pathology findings were compared. Result: Seventy-eight patients underwent BCS with IOF biopsy. Six patients showed positive IOF biopsy findings; five of these patients showed concordant permanent pathology findings. Sentinel lymph node biopsy (SLNB) was positive in one patient. Thirteen patients with invasive breast cancer were not diagnosed with IOF biopsy; they underwent SLNB during the second surgery. None of them had metastatic lymph nodes. The sensitivity and specificity of IOF biopsy were 27.7% and 98.3%, respectively, with 82.1% accuracy. None of the other factors showed statistically significant relationships with the permanent pathology findings, except for the IOF biopsy findings. Conclusion: IOF evaluation can aid in detecting the invasiveness of tumors in patients with preoperative DCIS.

As patients tend to be diagnosed with breast cancer at an early stage, the demand for better cosmetic outcomes has increased. Several studies revealed that robot-assisted nipple-sparing mastectomy (RNSM) shows favorable outcomes. The aim of the study was to reveal the feasibility of RNSM using the da Vinci single-port (SP) system with a minimal incision, hidden in the arm.From 2018 to 2021, 81 cases (70 patients) were retrospectively reviewed. Clinicopathologic characteristics, operative outcomes, and postoperative complications were evaluated. The operative outcomes were analyzed using the Mann-Whitney U test.The median age was 42 years (range, 26-60 years). Bilateral RNSM was performed in 11 (27.2%) patients. The median size of the initial skin incision was 40 mm (range, 20-55 mm). Immediate reconstruction with direct-to-implant was performed in 54 (66.7%) patients and deep inferior epigastric perforator (DIEP) flaps in 15 (18.5%) patients. Postoperative complications of Clavien-Dindo Classification III occurred in six (7.5%) patients. Patients reconstructed with a DIEP flap had large breasts with more severe ptosis, yet grade III complications did not occur.RNSM using the SP system can be applied for curative and risk-reducing mastectomy, regardless of breast size or ptosis grade.

Background: Most of breast cancer patients survive for a long-term period. The existing assessment of survivors’ prognosis has had some limitations in breast cancer because it is based on an evaluation at the time of diagnosis. Conditional survival reflects change over time after diagnosis and treatment of cancer. Conditional disease-free survival (CDFS) and conditional overall survival (COS) can provide more accurate prognosis to breast cancer patients. In this study, we aimed to determine 5-years CDFS and COS according to disease-free period after diagnosis and treatment of breast cancer in Korea. Method: We retrospectively reviewed clinical data of 5664 patients aged 16 to 86 who underwent curative surgery for breast cancer between January 2000 and December 2008 at Samsung Medical Center, a single tertiary hospital in Korea. The CDFS and COS rates were based on cumulative DFS and OS estimates up to 15 years using the Kaplan-Meier method. Results: At baseline, each 5-years DFS and OS were 88.0% and 93.8%. For patients who kept disease free status from 1 to 9 years after surgery, the 5-years CDFS rates were calculated as 88.7%, 90.7%, 91.6%, 91.1%, 91.5%, 91.0%, 89.5%, 86.1% and 86.1%, respectively. The 5-year COS rates of the patients who had survived from 1 to 9 years after surgical treatment were calculated as 92.6%, 92.1%, 91.2%, 91.0%, 89.4%, 85.6%, 80.7%, 75.3%, and 73.0%, respectively. Conclusion: Our study showed that 5-years CDFS and COS for most patients who have breast cancer in Korea seemed to be good prognosis for a long time. However, cancer recurrence tended to occur after a long period postoperatively. Further study is required to identify risk factors associated with recurrence after several years in Korean breast cancer patients. Citation Format: Jee Hyun Ahn, Seok Jin Nam, Seok Won Kim, Jeong Eon Lee, Byung-Joo Chae, Se Kyung Lee, Jai Min Ryu, Jonghan Yu. The 5-years conditional disease free survival and overal survival for breast cancer patients in Korea [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-08-25.

The GenesWell™ breast cancer test (BCT) is a recently developed multigene assay that predicts the risk of distant recurrence in patients with hormone receptor-positive (HR+) and human epidermal growth factor-2 negative (HER2-) early breast cancer (BC). The ability of this assay to predict the response to neoadjuvant chemotherapy (NACT) has not been established to date.Biopsy specimens from HR+/HER2- BC patients with axillary lymph node (LN) metastasis who underwent NACT were analyzed using the BCT score. The modified BCT score was developed and patients classified into high-and low-response groups. A total of 88 patients were available for the BCT score among the 108 eligible patients. The median follow-up duration was 35.9 (7.8-128.5) months.Among them, 61 (65.1%) had cN1 and 53 (60.2%) had cT1 or cT2 disease. The BCT score was low in 25 (28.4%) patients and high in 63 (71.6%). Among the 50 patients with pathologic complete response or partial response, 41 (82.0%) were in the high BCT score group and 9 (18.0%) were in the low BCT score group. Among the 38 patients with stable or progressive disease, 22 (57.9%) were in the high BCT score group and 16 (42.1%) were in the low BCT score group (We demonstrated that the BCT score predicts NACT responsiveness in HR+/HER2- BC with LN metastasis and might help determine whether NACT should be performed. Further studies are required to validate these results.

Simple Summary Patients whose breast cancers express low levels of hormone receptor (HR) could be eligible for adjuvant endocrine therapy; however, limited data are available to support this notion. Our retrospective study investigated the characteristics and survival of 6042 breast cancer patients according to four HR groups of combined estrogen and progesterone receptor expression. HR expression levels were prognostic for its recurrence and death of patients with breast cancer. Patients whose tumors expressed high levels of a single HR had the worst survival outcomes, and their risk of death continuously increased even after the 10-year follow-up. Endocrine therapy had a significant benefit for those whose tumors expressed high HR levels and a favorable tendency for patients with tumors expressing low HR levels. We established the value of HR expression level as a prognostic factor and the possible benefit of endocrine therapy for patients whose breast tumors expressed low HR levels. Abstract Hormone receptor (HR)-positive breast cancer has a heterogeneous pattern according to the level of receptor expression. Patients whose breast cancers express low levels of estrogen receptor (ER) or progesterone receptor (PgR) may be eligible for adjuvant endocrine therapy, but limited data are available to support this notion. We aimed to determine whether HR expression level is related to prognosis. Tumors from 6042 patients with breast cancer were retrospectively analyzed for combined HR levels of ER and PgR. Low expression was defined as ER 1–10% and PgR 1–20%. Four HR groups were identified by combining ER and PgR expression levels. Patients whose tumors expressed high levels of a single receptor showed the worst survival outcomes, and their risk continuously increased even after the 10-year follow-up. Endocrine therapy had a significant benefit for patients whose tumors expressed high HR levels and a favorable tendency for patients with tumors expressing low HR levels. We established the possible benefit of endocrine therapy for patients whose breast tumors expressed low HR levels. Thus, HR level was a prognostic factor and might be a determinant of extended therapy, especially for patients with high expression of a single receptor.

The GenesWell™ BCT (BCT score) is a recently developed multigene assay that predicts the risk of distant recurrence in patients with hormone receptor-positive (HR+) and HER2 negative (HER2-) early breast cancer (BC). The ability of the assay to predict the response to neoadjuvant chemotherapy (NACT) has not been established to date. Biopsy specimens of HR+/HER2- BC patients with axillary lymph node (LN) metastasis who underwent NACT were analyzed using the BCT score. The modified breast cancer test (BCT) score was developed and classified into high-and low-response groups. A total of 88 patients were available for the BCT score among 108 eligible patients. The median follow-up duration was 35.9 (7.8-128.5) months. Among these, 61 (65.1%) had cN1 and 53 (60.2%) had cT1 or T2. The BCT score was low in 25 (28.4%) patients and high in 63 (71.6%) patients. Among 50 patients with pathologic complete response or partial response, 41 (82.0%) were in the high-response group, and 9 (18.0%) were in the low-response group. Among 38 patients with stable disease or progressive disease, 22 (57.9%) patients were in the high-response group, and 16 (42.1%) were in the low-response group (p = 0.025). Ki-67 before NACT was a significant factor for predicting tumor response (p = 0.006; 3.81 [1.50-10.16]). The BCT score showed a significant response to NACT (p = 0.016; 4.18 [1.34–14.28]). A significant difference was found in distant metastasis-free survival between the high and low response groups (p = 0.004). We demonstrated that the BCT score predicts NACT responsiveness of HR+/HER2- BC with LN metastasis and might help determine whether to undergo NACT or not. Further studies are warranted to validate these findings.

576 Background: To obtain a clear resection margin during breast-conserving surgery (BCS) after neoadjuvant chemotherapy (NCT), accurate targeting of the location and assessment extent of the tumor are essential. However, conventional targeting methods such as USG/MMG guided hook wire insertion have disadvantages in that they could only localize the tumor, not reflecting its extent. To assess this problem, we developed an MRI-based 3D printed breast surgical guide (3DP-BSG) and conducted a multicenter randomized clinical study to prove its clinical effectiveness. Methods: In this multicenter, randomized (1:1), controlled trial (KCT0004469), we assigned 566 patients who underwent NCT and planned to undergo BCS, to use customized 3DP-BSG for lumpectomy, or not to use 3DP-BSG for lumpectomy. We assumed that 3DP-BSG group achieve non-inferior outcomes compared with control group with conventional targeting method. The primary endpoint was the margin positivity of the first resected margin. Under the assumption that the proportion of margin positivity would be 23% in both groups, a total of 438 patients were calculated to have 80% power to establish non-inferiority with a margin of 10% at a one-sided significance level of 0.05. Efficacy was assessed in the intention-to-treat (ITT) population. Results: Between 2019 and 2021, 282 (49.8%) patients were assigned to 3DP-BSG group, and 284 (50.2%) patients were assigned to control group with conventional targeting method. The median age was 51 years. In the ITT analysis, first resected margin was positivity in 5 (2.1%) of 235 patients in 3DP-BSG group and 7 (2.9%) of 244 patients in control group (difference -1.15 [95% CI -3.58 to -1.28], pnon-inferiority

Xylene is a hazardous volatile organic compound, which should be measured precisely for monitoring of indoor air quality. The selective detection of ppm-level xylene using oxide semiconductor chemiresistors, however, remains a challenging issue. In this study, NiO/NiMoO4 nanocomposite hierarchical spheres assembled from nanosheets were prepared by hydrothermal reaction, and the potential of sensors composed of these nanocomposites to selectively detect xylene gas was investigated. The sensors based on the NiO/NiMoO4 nanocomposite hierarchical spheres exhibited high responses (maximum resistance ratio =101.5) to 5 ppm p-xylene with low cross-responses (resistance ratios

The pure and 0.3 wt% Pt-doped SnO2 hollow nanospheres were prepared by the oxidation of pure and Pt-doped Sn nanoscrystals embedded in carbon matrix and their gas sensing characteristics were investigated. The formation of hollow morphology was attributed to the nanoscale Kirkendall effect due to rapid outward diffusion of Sn ions and relatively slow inward diffusion of oxygen. Pure SnO2 hollow nanospheres showed a high response (resistance ratio) of 93.3 when exposed to 5 ppm ethanol. The response to 5 ppm ethanol was significantly increased to 1399.9 with doping 0.3 wt% Pt. In addition, selectivity to ethanol was also enhanced by Pt doping. Ultrasensitive and selective detection of ethanol in pure and Pt-doped SnO2 nanospheres is explained by the effective electron depletion in hollow structures and catalytic promotion of gas sensing reaction.

Phase-pure β-NiMoO 4 yolk-shell spheres for lithium-ion battery anodes were prepared for the first time by one-pot spray pyrolysis, and their electrochemical properties were investigated. The yolk-shell-structured β-NiMoO 4 powders exhibited high initial discharge/charge capacities (1634/1253 mA h g −1 ) at a current density of 1000 mA g −1 . After 200 cycles, these powders exhibited a high discharge capacity of 1292 mA h g −1 , whereas the initial discharge capacity (1341 mA h g −1 ) of the filled structured NiMoO 4 powders was dramatically decreased to 479 mA h g −1 . The significant enhancement of the cycling performance of the β-NiMoO 4 powders with ultrafine crystallite size was attributed to the structural stability of the yolk-shell structure.

Highly porous NiO–gadolinium-doped ceria (GDC) nano-composite powders are synthesized by a one-pot glycine nitrate process and applied to the fabrication of Ni–YSZ (yttria-stabilized zirconia)-supported tubular solid oxide fuel cells (SOFCs) with a cell configuration of Ni–YSZ/Ni/Ni–GDC/GDC/LSCF (La0.6Sr0.4Co0.2Fe0.8O3−δ)–GDC/LSCF. The power density of the cell is as high as 413mWcm−2 at 600°C, which is 1.37 times higher than that of an identically configured cell fabricated using ball milling-derived NiO–GDC powders (301mWcm−2). The high porosity of the powders and the good mixing between the NiO and GDC primary nanoparticles due to the abrupt combustion of the precursors effectively suppress the densification, coarsening, and agglomeration of NiO and GDC particles during sintering, resulting in a highly porous Ni–GDC anode layer with good dispersion of Ni and GDC particles and a cell with significantly enhanced power density.

Highly sinterable gadolinia doped ceria (GDC) powders are prepared by carbonate coprecipitation and applied to the GDC interlayer in Ni–YSZ (yttria stabilized zirconia)-supported tubular solid oxide fuel cell in order to prevent the reaction between YSZ electrolyte and LSCF (La0.6Sr0.4Co0.2Fe0.8O3−δ) cathode materials. The formation of highly resistive phase at the YSZ/LSCF interface was effectively blocked by the low-temperature densification of GDC interlayer using carbonate-derived active GDC powders and the suppression of Sr diffusion toward YSZ electrolyte via GDC interlayer by tuning the heat-treatment temperature for cathode fabrication. The power density of the cell with the configuration of Ni–YSZ/YSZ/GDC/LSCF–GDC/LSCF was as high as 906 mW cm−2, which was 2.0 times higher than that (455 mW cm−2) of the cell with the configuration of Ni–YSZ/YSZ/LSM(La0.8Sr0.2MnO3−δ)–YSZ/LSM at 750 °C.

A cylindrical Li 7 La 3 Zr 2 O 12 specimen in contact with an Al 2 O 3 crucible is sintered and the effect of Al diffusion on the microstructure, phase composition, and Li-ion conductivity of Li 7 La 3 Zr 2 O 12 is investigated. The decrease in the Li-ion conductivity and Al concentration with increasing distance from the contact area with the Al 2 O 3 crucible is confirmed using spatially resolved local-impedance spectroscopy and compositional analysis. The region close to the Al 2 O 3 crucible shows abnormally large grains (size > 0.7 mm) within a matrix of fine grains (size: ∼10 μm), abundant intergranular liquid, the Li 7 La 3 Zr 2 O 12 phase mostly in cubic form, and a high Li-ion conductivity (8.5 × 10 −5 S cm −1 ). In contrast, the region far from the Al 2 O 3 crucible exhibits uniform fine grains (size: ∼10 μm), scarce intergranular liquid, the tetragonal form of the Li 7 La 3 Zr 2 O 12 phase, and a low Li-ion conductivity (1.1 × 10 −6 S cm −1 ). The incorporation of Al into the Li 7 La 3 Zr 2 O 12 lattice and the resulting increase in the number of Li-ion vacancies is suggested to be the main reason for the increase in the Li-ion conductivity. The origins of the abnormal grain growth induced by the diffusion of Al are discussed in relation to the atomic surface structures of Li 7 La 3 Zr 2 O 12 and the presence of intergranular liquid phase.

Xylene is a hazardous volatile organic compound, which should be measured precisely for monitoring of indoor air quality. The selective detection of ppm-level xylene using oxide semiconductor chemiresistors, however, remains a challenging issue. In this study, NiO/NiMoO

Gadolinia-doped ceria (GDC, Gd0.1Ce0.9O1.95) powders with high sinterability are prepared by carbonate coprecipitation and applied in the fabrication of Ni–YSZ (yttria-stabilized zirconia)-supported tubular solid oxide fuel cells (SOFCs) with a cell configuration of Ni–YSZ/Ni/Ni–GDC/GDC/LSCF(La0.6Sr0.4Co0.2Fe0.8O3−δ)–GDC/LSCF. A high power density (594 mW cm−2) at 600 °C is achieved using the cell (diameter: 6 mm) prepared by sintering of the electrolyte at 1400 °C. This result is attributed to the dense electrolyte and good adherence between GDC and the electrode. The carbonate-derived GDC powders can be sintered to 97% of the theoretical density even at 1050 °C, which demonstrates that the fabrication temperature of tubular SOFCs can potentially be lowered by using cost-effective Ni–YSZ supports.