Impact of intrapulmonary tumour location of non-small-cell lung cancer on surgical outcomes for segmentectomy.

OBJECTIVES: While segmentectomy is considered a viable option for small peripheral non-small-cell lung cancer, its efficacy for central lesions remains uncertain. This study aimed to assess the oncological outcomes of segmentectomy for central lesions compared to peripheral ones. METHODS: We retrospectively examined 338 clinical stage IA non-small-cell lung cancer patients who underwent thoracoscopic anatomical segmentectomy at our institution from January 2013 to December 2021. Patients were divided into 2 groups based on intrapulmonary tumour location: inner two-thirds (central group, n = 82) and outer one-third (peripheral group, n = 256). RESULTS: The gender, body mass index, performance score, smoking, comorbidities and preoperative pulmonary function were similar in both groups. On computed tomography images, tumour diameter and consolidation-to-tumour ratio were comparable between the groups. The central group had significantly greater tumour-to-pleura distances [mm, 23 (18-27) vs 11 (8-14); P < 0.001], shorter margin distances [mm, 20 (15-20) vs 20 (20-20); P < 0.001] and larger resected lung volumes based on subsegment count [4 (3-6) vs 3 (3-5); P = 0.004] than the peripheral group. Surgery duration, bleeding, hospitalization or drainage period, mortality, readmission and pathological stage were equivalent between the groups. The central group showed significantly more postoperative pleural effusions (5% vs 1%; P = 0.03) than the peripheral group, with no adverse impact on postoperative pulmonary functions. During the follow-up period, local-only recurrence rates were 0% and 8% in the respective groups (Gray test P = 0.07), and total recurrence rates were 6% and 11% (Gray test P = 0.70), with no significant differences. Moreover, no significant inter-group difference in overall survival rates was observed (82% vs 93%; P = 0.15). CONCLUSIONS: Segmentectomy may be a promising therapeutic option for early-stage non-small-cell lung cancer located in the inner two-thirds of the parenchyma.

Single-cell sequencing on CD8+ TILs revealed the nature of exhausted T cells recognizing neoantigen and cancer/testis antigen in non-small cell lung cancer.

BACKGROUND: CD8+tumor infiltrating lymphocytes (TILs) are often observed in non-small cell lung cancers (NSCLC). However, the characteristics of CD8+ TILs, especially T-cell populations specific for tumor antigens, remain poorly understood. METHODS: High throughput single-cell RNA sequencing and single-cell T-cell receptor (TCR) sequencing were performed on CD8+ TILs from three surgically-resected lung cancer specimens. Dimensional reduction for clustering was performed using Uniform Manifold Approximation and Projection. CD8+ TIL TCR specific for the cancer/testis antigen KK-LC-1 and for predicted neoantigens were investigated. Differentially-expressed gene analysis, Gene Set Enrichment Analysis (GSEA) and single sample GSEA was performed to characterize antigen-specific T cells. RESULTS: A total of 6998 CD8+ T cells was analyzed, divided into 10 clusters according to their gene expression profile. An exhausted T-cell (exhausted T (Tex)) cluster characterized by the expression of ENTPD1 (CD39), TOX, PDCD1 (PD1), HAVCR2 (TIM3) and other genes, and by T-cell oligoclonality, was identified. The Tex TCR repertoire (Tex-TCRs) contained nine different TCR clonotypes recognizing five tumor antigens including a KK-LC-1 antigen and four neoantigens. By re-clustering the tumor antigen-specific T cells (n=140), it could be seen that the individual T-cell clonotypes were present on cells at different stages of differentiation and functional states even within the same Tex cluster. Stimulating these T cells with predicted cognate peptide indicated that TCR signal strength and subsequent T-cell proliferation and cytokine production was variable but always higher for neoantigens than KK-LC-1. CONCLUSIONS: Our approach focusing on T cells with an exhausted phenotype among CD8+ TILs may facilitate the identification of tumor antigens and clarify the nature of the antigen-specific T cells to specify the promising immunotherapeutic targets in patients with NSCLC.

Thoracoscopic Anatomical Sublobar Resection Including Subsegmentectomy for Non-Small Cell Lung Cancer.

BACKGROUND: Among anatomical sublobar resection techniques for non-small cell lung cancer (NSCLC), the clinical benefit of subsegmentectomy remains unclear. We investigated whether anatomical sublobar resection including subsegmentectomy-segmental resection with subsegmental additional resection or subsegmental resection alone-is an effective and feasible surgical procedure for NSCLC. METHODS: We retrospectively reviewed data of 285 patients with clinical stage I NSCLC who underwent anatomical sublobar resection at our institution from January 2013 to March 2021 and compared surgical outcomes between patients who underwent anatomical sublobar resection including (IS; n = 50) and excluding (ES; n = 235) subsegmentectomy. RESULTS: No significant intergroup differences were noted in terms of age, sex, smoking, comorbidities, tumor size or location, consolidation tumor ratio, and preoperative pulmonary function. The IS group had more preoperative computed tomography-guided markings (34 vs. 15%; p = .004) and smaller resected lung volumes converted to the total subsegment number [3 (2-4) vs. 3 (3-6); p = .02] than the ES group. No significant differences in margin distance [mm, 20 (15-20) vs. 20 (20-20); p = .93], readmission rate (2% vs. 3%; p > .99), and intraoperative (8% vs. 7%; p = .77) or postoperative (8% vs. 10%; p = .80) complication rates were observed, and the 5-year local recurrence-free survival (91% vs. 90%; p = .92) or postoperative pulmonary function change were comparable between both groups. CONCLUSIONS: Although further investigations are required, anatomical sublobar resection including subsegmentectomy for clinical stage I NSCLC could be an acceptable therapeutic option.

Association of the KRAS genotype and clinicopathologic findings of resected non-small-cell lung cancer: A pooled analysis of 179 patients.

BACKGROUND: This study assessed the clinicopathological background of early-stage KRAS-mutated non-small-cell lung cancer and analyzed the biological process of KRAS-mutated tumor using an RNA sequencing procedure. PATIENTS AND METHODS: We used a cohort of consecutive series of 179 surgically resected early-stage non-small-cell lung cancers harboring KRAS mutations and analyzed the clinicopathological features, including the KRAS genotypes, affecting the recurrence-free survival and prognosis. Consequently, we performed RNA sequencing to determine the gene expression profiles of nineteen KRAS-mutated non-small-cell cancers. RESULTS: The most common KRAS genotype was p.G12C (57; 31.8%). A high p-stage (hazard ratio [HR], 4.181; P < 0.0001) and solid predominant adenocarcinoma histology (HR, 2.343; P = 0.0076) were significant independent prognostic factors for the recurrence-free survival. A high p-stage (HR, 3.793; P < 0.0001), solid predominant adenocarcinoma histology (HR, 2.373; P = 0.0147), and KRAS p.G12V genotype (HR, 1.975; P = 0.0407) were significant independent prognostic factors for the overall survival. A gene expression analysis of the two factors revealed the p.G12V genotype to be closer to those of stem cells, and the traits of e an enhanced fatty acid and amino acid metabolism. as well as And a solid predominant phenotype were shown to an acquired a trait that can withstand hypoxia and the effect of prostaglandin-endoperoxide synthase. CONCLUSION: The KRAS p.G12V genotype and solid predominant adenocarcinoma phenotype may be independent predictive factors of a poor clinical course in resected early-stage non-small-cell lung cancers, possibly due to the differentiation tendency observed in stem cells, the trait of an enhanced fatty acid and amino acid metabolism, and the effect of prostaglandin-endoperoxide synthase.

New evaluation of the tumor immune microenvironment of non-small cell lung cancer and its association with prognosis.

BACKGROUND: A better understanding of the tumor immune microenvironment (TIME) will facilitate the development of prognostic biomarkers and more effective therapeutic strategies in patients with lung cancer. However, little has been reported on the comprehensive evaluation of complex interactions among cancer cells, immune cells, and local immunosuppressive elements in the TIME. METHODS: Whole-exome sequencing and RNA sequencing were carried out on 113 lung cancers. We performed single sample gene set enrichment analysis on TIME-related gene sets to develop a new scoring system (TIME score), consisting of T-score (tumor proliferation), I-score (antitumor immunity) and S-score (immunosuppression). Lung cancers were classified according to a combination of high or low T-score, I-score, and S-scores (eight groups; G1-8). Clinical and genomic features, and immune landscape were investigated among eight groups. The external data sets of 990 lung cancers from The Cancer Genome Atlas and 76 melanomas treated with immune checkpoint inhibitors (ICI) were utilized to evaluate TIME scoring and explore prognostic and predictive accuracy. RESULTS: The representative histological type including adenocarcinoma and squamous cell carcinoma, and driver mutations such as epidermal growth factor receptor and TP53 mutations were different according to the T-score. The numbers of somatic mutations and predicted neoantigens were higher in Thi (G5-8) than Tlo (G1-4) tumors. Immune selection pressure against neoantigen expression occurred only in Thi and was dampened in Thi/Ilo (G5-6), possibly due to a reduced number of T cells with a high proportion of tumor specific but exhausted cells. Thi/Ilo/Shi (G5) displayed the lowest immune responses by additional immune suppressive mechanisms. The T-score, I-score and S-scores were independent prognostic factors, with survival curves well separated into eight groups with G5 displaying the worst overall survival, while the opposite group Tlo/Ihi/Slo (G4) had the best prognosis. Several oncogenic signaling pathways influenced on T-score and I-scores but not S-score, and PI3K pathway alteration correlated with poor prognosis in accordance with higher T-score and lower I-score. Moreover, the TIME score predicted the efficacy of ICI in patients with melanoma. CONCLUSION: The TIME score capturing complex interactions among tumor proliferation, antitumor immunity and immunosuppression could be useful for prognostic predictions or selection of treatment strategies in patients with lung cancer.

Pulmonary Mucormycosis Involving the Left Main Bronchus and the Pulmonary Artery.

Pulmonary mucormycosis is an extremely rare disease. It often occurs in immunocompromised patients, such as patients with diabetes and those on long-term steroid use. The prognosis of the disease is poor despite the administration of antifungal agents and removal of the necrotic tissue. Herein, we present a successfully treated case of pulmonary mucormycosis in a patient with type 2 diabetes who underwent left pneumonectomy because of the involvement of the left main pulmonary artery and the left main bronchus. Irrespective of the infected organ, complete debridement of the infected tissue and treatment with antifungal agents are essential for treating mucormycosis.

Postoperative Delirium in Lung Cancer Anatomical Resection-Analysis of Risk Factors and Prognosis.

BACKGROUND: The incidence of postoperative delirium after anatomical lung resection ranges from 5 to 16%. This study aimed to analyze the risk factors and prognosis of postoperative delirium in anatomical lung resection for lung cancer. METHODS: This study included 1351 patients undergoing anatomical lung resection between April 2010 and October 2020. We analyzed the perioperative risk factors of postoperative delirium. We also compared postoperative complications and survival between the delirium and non-delirium groups. RESULTS: Postoperative delirium was identified in 44 (3.3%) of 1351 patients who underwent anatomical lung resection for lung cancer. Age, peripheral vascular disease, depression, and current smoking status were independent risk factors for postoperative delirium in the multivariate analysis. The percentage of postoperative delirium was 0.6% in never smokers and 6.0% in current smokers. The delirium and non-delirium groups showed significant differences in overall survival (p = 0.0144) and non-disease-specific survival (p = 0.0080). After propensity score matching, the two groups did not significantly differ in overall survival (p = 0.9136), non-disease-specific survival (p = 0.8146), or disease-specific survival (p = 0.6804). CONCLUSIONS: Age, peripheral vascular disease, depression, and current smoking status were considered independent risk factors for postoperative delirium in anatomical lung resection for lung cancer. Smoking cessation for at least four weeks before surgery is recommended for reducing incidence of post-operative delirium.

Successful excision of a giant subcarinal bronchogenic cyst by video-assisted thoracoscopic surgery.

Mediastinal bronchogenic cysts, regarded as congenital foregut abnormalities, are uncommon. These cysts can compress adjacent structures, causing obstructive symptoms and complications. A 57-year-old man was admitted to our hospital with complaints of tachycardia, dyspnea, and chest pain. Enhanced computed tomography revealed a 90 × 90 mm, well-defined subcarinal cystic mass causing significant compression and stenosis of the right main bronchus, right pulmonary artery, and right inferior pulmonary vein. The mass was successfully excised using one window and two-port video-assisted thoracoscopic surgery with partial resection and repair of pulmonary artery, and the postoperative course was good with no recurrence.

Clinical Guideline-Guided Outcome Consistency for Surgically Resected Stage III Non-Small Cell Lung Cancer: A Retrospective Study.

Clinical guidelines can help reduce the use of inappropriate therapeutics due to localism and individual clinician perspectives. Nevertheless, despite the intention of clinical guidelines to achieve survival benefit or desirable outcomes, they cannot ensure a robust outcome. This retrospective study aimed to investigate whether guideline-consistency, including adjuvant treatments after surgical resection (ATSR) and guideline-matched first-line treatment for recurrence (GMT-R), according to the genomic profiles and immune status, could influence overall survival (OS). From 2006 to 2017, the clinical data of 308 patients with stage III non-small cell lung cancer (NSCLC) after surgical resection were evaluated. ATSR and GMT-R were allowed in 164 (53.2%) and 129 (62.3%) patients cases after surgical pulmonary resection, among which 207 (67.2%) recurrences were identified. The 5-year OS in guideline-consistent cases was significantly better than that in guideline-inconsistent cases (p < 0.01). Subgroup analyses further showed that the 5-year OS after propensity adjustment was significantly better in guideline-consistent than in guideline-inconsistent cases (p < 0.01), but not in either ATSR or GMT-R (p = 0.24). These data suggest that the guideline-consistent alternatives, which comprise ATSR or GMT-R, can contribute to survival benefits in pathological stage III NSCLC. However, only either ATSR or GMT-R has a potential survival benefit in these patients.

Feasibility of intraoperative diagnosis of lung adenocarcinoma in situ to avoid excessive resection.

BACKGROUND: Limited lung resection is generally believed to be available for lung adenocarcinoma in situ (AIS). At our institute, intraoperative hematoxylin-eosin staining of frozen-section slides is routinely performed for evaluating tumor invasiveness after partial resection to avoid excessive lung resection. This study aimed to evaluate the feasibility and usefulness of intraoperative frozen-section diagnosis of AIS. METHODS: We retrospectively reviewed 143 patients with 151 AISs diagnosed by intraoperative frozen sections between 2012 and 2019 at our institute. All patients underwent limited resection because of the result of intraoperative frozen-section diagnosis. RESULTS: The total concordance rate between the diagnoses of AIS by intraoperative frozen sections and postoperative paraffin-embedded sections was 82.7% for 151 nodules. Although 21 minimally invasive adenocarcinomas (MIA) and 5 invasive adenocarcinomas were diagnosed as AIS intraoperatively, no patient had tumor recurrence after resection. Among 125 pathologically proven cases of AIS postoperatively, there were 67 (53.6%) radiologically invasive tumors including ground-glass nodules (GGNs) with part-solid component or pure-solid nodules. CONCLUSIONS: This intraoperative evaluation of frozen-section slides will help surgeons avoid excessive lung resection for AIS that was radiologically diagnosed as invasive adenocarcinoma. Intraoperative frozen-section diagnosis will provide to be clinically useful and lead to less invasive surgical treatment for lung nodules.

Subsegmental resection preserves regional pulmonary function: A focus on thoracoscopy.

BACKGROUND: The aim of this study was to evaluate regional postoperative preserved pulmonary function (PPPF) and three-dimensional (3D) volumetric changes according to the number of resected subsegments and investigate the factors that most affected pre-/post PPPF. METHODS: Patients who underwent thoracoscopic lobectomy (n = 73), and segmentectomy (n = 87) were eligible for inclusion in the study. They were classified according to the number of resected subsegments which ranged from 1 to 10. The percentage of pre-/postoperative forced expiratory volume in 1 s (FEV1) was used for comparison. Furthermore, lung volumetric changes were calculated using 3D computed tomography (CT) volumetry. RESULTS: The percentage of pre-/postoperative EFV1 between 4 and 5-7 and between 5-7 and 10 were significant (p = 0.03 and p < 0.01, respectively), but not between 1-2 to 4 (p = 0.99). The difference between volumetric changes in the left lower lobe of patients with a number of resected subsegments was significant (p < 0.01). On univariate and multivariate analyses, chronic inflammation was significant for decrease in recovery percentages. When the PPPF was compared among resected subsegments, it gradually decreased with an increase in the number of patients without a postoperative procrastination of inflammation (p < 0.01). CONCLUSIONS: Segmentectomy is feasible and useful for PPPF. Even a relatively large-volume resection procedure where 5-7 subsegments are resected can preserve pulmonary function. Chronic inflammation was statistically identified as a risk factor for postoperative preserved pulmonary function. KEY POINTS: .

Lymphatic permeation and vascular invasion should not be integrated as lymphovascular invasion in lung adenocarcinoma.

OBJECTIVE: Lymphatic permeation (LY) and vascular invasion (VI) are well-known as postoperative prognostic factors in non-small cell lung cancer (NSCLC). Some reports use the term "lymphovascular invasion (LVI)" in reference to the integration of LY and VI. The purpose in this study is to elucidate whether NSCLC with LY or VI can be labeled as LVI-positive NSCLC or it should be treated as an LY- or VI-positive tumor, respectively. METHODS: We reviewed 601 completely resected lung adenocarcinomas and squamous cell carcinomas, and examined the respective prognostic and biological significance of LY and VI. RESULTS: Among 454 adenocarcinomas, multivariate survival analyses showed that LY and VI were unfavorable prognostic factors in stages II and III and stages I and II, respectively. Conversely, this relationship was not found among 147 squamous cell carcinomas. Patients with adenocarcinomas with LY and VI had a significantly worse prognosis than those with adenocarcinomas with LY or VI in stage II, but not in stage I. Among 149 recurrent adenocarcinomas, only VI had a strong effect on early recurrence and shorter post-recurrence survival. LY and VI were predictors for multiple organ recurrence of adenocarcinoma. The recurrence of adenocarcinoma with LY was high in the ipsilateral mediastinal lymph nodes, whereas VI was significantly correlated with distant metastasis to organs, such as the brain, liver, and adrenal gland. CONCLUSIONS: LY and VI have differing effects postoperative prognosis and recurrence-relevant events, suggesting that these pathological findings should not be integrated as LVI.

How preserved regional pulmonary function after thoracoscopic segmentectomy in clinical stage I non-small cell lung cancers in right upper lobe.

OBJECTIVE: To investigate the efficacy of regional respiratory preservation after pulmonary resection for clinical stage I non-small cell lung cancer (NSCLC) in right upper lobe. METHODS: This retrospective study analysed patients with clinical stage I NSCLC who underwent open thoracotomy lobectomy (OTL, n = 45), thoracoscopic lobectomy (TSL, n = 137), and thoracoscopic segmentectomy (TSS, n = 37) in right upper lobe. The forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were examined at 3 and 6-12 months after the operation. The pre- and post-operative lung volumes were evaluated by three-dimensional reconstructed computed tomography. The rates of post- and pre-operative FVC, FEV1, and lung volumes were compared amongst the three groups. RESULTS: Significant differences were found in both FVC and FEV1 at 6-12 months between TSL and OTL (p < 0.01 and p = 0.02, respectively). The respiratory recovery rates of FVC and FEV1 at 6-12 months were significantly higher in TSS (98.6% ± 1.52% and 96.5% ± 1.66%) than in TSL (93.4% ± 0.79% and 90.4% ± 0.86%) (FVC: p < 0.01 and FEV1: p < 0.01). The volumetric changes were greater in TSL than in TSS for the right middle lobe (19.6% ± 2.39% and 9.59% ± 4.66%; p = 0.06) and right lower lobe (48.3% ± 2.84% and 27.9% ± 5.47%; p < 0.01) CONCLUSION: TSS might be superior to TSL or OTL depending on the moderate expansion of the remaining right lobes.

How long is cessation of preoperative smoking required to improve postoperative survival of patients with pathological stage I non-small cell lung cancer?

BACKGROUND: Smoking can cause non-small cell lung cancer (NSCLC). However, the effects of preoperative smoking on tumor progression are not well-known. In addition, the duration of smoking cessation that can provide NSCLC patients with smoking history similar postoperative prognosis as that of nonsmokers remains unknown. This study aimed to investigate the period of smoking cessation that may "compensate" for past smoking history regarding postoperative survival in cases of resected pathological stage I NSCLC by examining the relationship between clinicopathological factors and preoperative smoking. METHODS: We retrospectively examined clinicopathological factors including preoperative smoking status and postoperative survival in 453 patients with pathologically proven stage I NSCLC at our Institute. Smoking status was evaluated using the following four parameters: cigarettes per day, number of years of smoking, pack-years, and number of years since smoking cessation. RESULTS: Pathological factors that reflect tumor invasiveness including vascular invasion (VI) and pleural invasion (PL) were associated with the degree of preoperative smoking in adenocarcinomas, particularly invasive diameters of 2-3 cm. Such a relationship was not identified for non-adenocarcinomas. Heavy smoking status was significantly related to PL in lepidic or papillary predominant adenocarcinomas and to VI in acinar or solid predominant adenocarcinomas. Former smokers who quit smoking for ≥10 years had similar postoperative survival as non-smokers for adenocarcinoma ≤3 cm. CONCLUSIONS: Accumulative smoking habit correlated with VI and PL, particularly in 2-3 cm adenocarcinoma, whereas larger adenocarcinomas and non-adenocarcinomas of any size appear to grow and become invasive independent of preoperative smoking status. Longer smoking cessation ≥10 years can result in postoperative survival similar to that of non-smokers with adenocarcinomas ≤3 cm. Current smokers should quit smoking immediately to ensure longer survival even though they suffer from small-sized lung adenocarcinomas in the future.

Clinicopathological Factors Related to Recurrence Patterns of Resected Non-Small Cell Lung Cancer.

Even after complete resection, non-small cell lung cancer (NSCLC) shows preferential recurrence in the mediastinal lymph nodes, lungs, brain, bone, liver, and adrenal gland. However, the relationship between clinicopathological factors and recurrence patterns after resection has not been well-evaluated. Among 688 NSCLC cases with complete resection between 2004 and 2016, 233 cases recurred at our institute. On multivariate analyses, NSCLCs with lymph node metastasis and pulmonary metastasis at surgery commonly recurred in the mediastinal lymph nodes and lungs, respectively. Young age, adenocarcinoma, and vascular invasion were correlated with brain metastasis. Although no variable was associated with bone metastasis, vascular invasion was correlated with postoperative liver and adrenal gland metastasis. Pathologically proven stage II or III NSCLC, adenocarcinoma, and the presence of lymphatic permeation would result in multiple metastases. Vascular invasion, larger invasive size, and advanced stage were independent risk factors of early recurrence. Considering survival, vascular invasion, elderly age, and non-adenocarcinoma were unfavorable prognostic factors after recurrence. Some clinicopathological variables were correlated with organ-specific metastasis and post-recurrence survival. Particularly, vascular invasion was a biomarker of brain, liver, and adrenal gland metastases and a prognostic marker after recurrence among completely resected NSCLC. This information is useful for more frequent patient follow-up and identifying organ-specific distant metastasis.

Antiferromagnet-Semiconductor Van Der Waals Heterostructures: Interlayer Interplay of Exciton with Magnetic Ordering.

Van der Waals (vdW) heterostructures have attracted great interest because of their rich material combinations. The discovery of two-dimensional magnets has provided a new platform for magnetic vdW heterointerfaces; however, research on magnetic vdW heterointerfaces has been limited to those with ferromagnetic surfaces. Here, we report a magnetic vdW heterointerface using layered intralayer-antiferromagnetic MPSe3 (M = Mn, Fe) and monolayer transition-metal dichalcogenides (TMDs). We found an anomalous upshift of the excitonic peak in monolayer TMDs below the antiferromagnetic transition temperature in the MPSe3, capturing a signature of the interlayer exciton-magnon coupling. This is a concept extended from single materials to heterointerfaces. Moreover, this coupling strongly depends on the in-plane magnetic structure and stacking direction, showing its sensitivity to their magnetic interfaces. Our finding offers an opportunity to investigate interactions between elementary excitations in different materials across interfaces and to search for new functions of magnetic vdW heterointerfaces.

Materials design of Kitaev spin liquids beyond the Jackeli-Khaliullin mechanism.

The Kitaev spin liquid provides a rare example of well-established quantum spin liquids in more than one dimension. It is obtained as the exact ground state of the Kitaev spin model with bond-dependent anisotropic interactions. The peculiar interactions can be yielded by the synergy of spin-orbit coupling and electron correlations for specific electron configuration and lattice geometry, which is known as the Jackeli-Khaliullin mechanism. Based on this mechanism, there has been a fierce race for the materialization of the Kitaev spin liquid over the last decade, but the candidates have been still limited mostly to 4d- and 5d-electron compounds including cations with the low-spin d 5 electron configuration, such as Ir4+ and Ru3+. Here we discuss recent efforts to extend the material perspective beyond the Jackeli-Khaliullin mechanism, by carefully reexamining the two requisites, formation of the j eff = 1/2 doublet and quantum interference between the exchange processes, for not only d- but also f-electron systems. We present three examples: the systems including Co2+ and Ni3+ with the high-spin d 7 electron configuration, Pr4+ with the f 1-electron configuration, and polar asymmetry in the lattice structure. In particular, the latter two are intriguing since they may realize the antiferromagnetic Kitaev interactions, in contrast to the ferromagnetic ones in the existing candidates. This partial overview would stimulate further material exploration of the Kitaev spin liquids and its topological properties due to fractional excitations.

Favorable clinical application for segmental bronchial closure based on experiment results.

BACKGROUND: We previously reported the clinical application of powered vascular staple (PVS) for closure of subsegmental or segmental bronchus (SSB). This study aimed to measure breakdown pressure in experiment and to investigate bronchopleural fistula (BPF) after thoracoscopic segmentectomy (TS). METHODS: Part 1: a total of 30 cadaveric pigs were used, and bronchi were categorized into the following four groups: small [S, bronchial outer diameter (BOD) of 4-8 mm, n=8], medium (M, 9-10 mm, n=9), and large (L, >10 mm, n=13). We additionally added a single additional suture to compensate for weak sites with large BOD (group R, n=6). The pressure was slowly increased, and stump breakdown was observed. Part 2: we investigated the morbidity of BPF formation at follow-up of at least 6 months in a total of 217 patients. RESULTS: Part 1: the mean leak pressure was the highest in M, followed by groups S, R and L'. However, the significant difference was not found between S and R. Part 2: no BPF was observed, clinically. CONCLUSIONS: Based on experimental results and clinical experience, the proper selection of PVS should contribute to the safety, feasibility, and success as SSB closure.