Revealing the Hidden Spin-Polarized Bands in a Superconducting Tl Bilayer Crystal.

The interplay of spin-orbit coupling and crystal symmetry can generate spin-polarized bands in materials only a few atomic layers thick, potentially leading to unprecedented physical properties. In the case of bilayer materials with global inversion symmetry, locally broken inversion symmetry can generate degenerate spin-polarized bands, in which the spins in each layer are oppositely polarized. Here, we demonstrate that the hidden spins in a Tl bilayer crystal are revealed by growing it on Ag(111) of sizable lattice mismatch, together with the appearance of a remarkable phenomenon unique to centrosymmetric hidden-spin bilayer crystals: a novel band splitting in both spin and space. The key to success in observing this novel splitting is that the interaction at the interface has just the right strength: it does not destroy the original wave functions of the Tl bilayer but is strong enough to induce an energy separation.

Dynamic topological domain walls driven by lithium intercalation in graphene.

Stacking engineering in van der Waals (vdW) materials is a powerful method to control topological electronic phases for quantum device applications. Atomic intercalation into the vdW material can modulate the stacking structure at the atomic scale without a highly technical protocol. Here we report that lithium intercalation in a topologically structured graphene/buffer system on SiC(0001) drives dynamic topological domain wall (TDW) motions associated with stacking order change by using an in situ aberration-corrected low-energy electron microscope in combination with theoretical modelling. We observe sequential and selective lithium intercalation that starts at topological crossing points (AA stacking) and then selectively extends to AB stacking domains. Lithium intercalation locally changes the domain stacking order to AA and in turn alters the neighbouring TDW stacking orders, and continuous intercalation drives the evolution of the whole topological structure network. Our work reveals moving TDWs protected by the topology of stacking and lays the foundation for controlling the stacking structure via atomic intercalation. These findings open up new avenues to realize intercalation-driven vdW electronic devices.

Direct Probe of the Ferromagnetic Proximity Effect at the Interface of SnTe/Fe Heterostructure by Polarized Neutron Reflectometry.

Introducing magnetic order into a topological insulator (TI) system has attracted much attention with an expectation of realizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) and axion insulator states. The magnetic proximity effect (MPE) is one of the promising schemes to induce the magnetic order on the surface of a TI without introducing disorder accompanied by doping magnetic impurities in the TI. In this study, we investigate the MPE at the interface of a heterostructure consisting of the topological crystalline insulator (TCI) SnTe and Fe by employing polarized neutron reflectometry. The ferromagnetic order penetrates ∼2.2 nm deep into the SnTe layer from the interface with Fe, which persists up to room temperature. This is induced by the MPE on the surface of the TCI preserving the coherent topological states without introducing the disorder by doping magnetic impurities. This would open up a way for realizing next-generation spintronics and quantum computational devices.

External Validation of a Prognostic Model Predicting Metastatic Castration-Resistant Prostate Cancer Survival in Patients Receiving Post-Docetaxel Second-Line Chemotherapy.

Introduction: The Halabi model predicts the overall survival (OS) of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with second-line therapy after docetaxel. We aimed to validate this model externally with an independent cohort, outside the setting of a clinical trial. Methods: In a multi-institutional study, we included 66 patients treated with cabazitaxel after docetaxel for mCRPC. Patients were stratified according to the two- and three-risk groups of the Halabi nomogram. Kaplan-Meier and Cox proportional hazard analyses were performed to estimate survival and hazard ratios (HRs). The model performance was assessed using receiver operating characteristic curves, and the associated c-index (area under the curve [AUC]). Results: The median OS in the two-risk groups was 5.06 months in the high-risk group (n=22) and 12.9 months in the low-risk group (n=44, p<0.001). High-risk patients had an HR of 9.50 (95% confidence interval (CI) 4.12-21.6, p<0.001) compared to low-risk patients. For the three-risk groups, the median OS was 6.44 months in the high-risk group (n=15), 5.75 months in the intermediate-risk group (n=11), and 13.7 months in the low-risk group (n=40, p=0.84). Compared to low-risk patients, intermediate-risk patients had an HR of 7.49 (95% CI 3.08-20.4, p<0.001), and high-risk patients had an HR of 8.48 (95% CI, 3.39-21.7, p<0.001). The AUC was 0.72 (95% CI 0.64-0.76) for the two-risk stratification. When comparing different risks, the AUCs were 0.48 (high vs intermediate), 0.66 (high vs low), and 0.65 (intermediate vs low). Conclusions: The two-risk stratification version but not the three-risk group analysis confirmed the ability of the model to predict survival. These results support the value of the Halabi nomogram in men receiving post-docetaxel second-line chemotherapy for mCRPC.

Two-Dimensional Superconductivity of Ca-Intercalated Graphene on SiC: Vital Role of the Interface between Monolayer Graphene and the Substrate.

Ca-intercalation has enabled superconductivity in graphene on SiC. However, the atomic and electronic structures that are critical for superconductivity are still under discussion. We find an essential role of the interface between monolayer graphene and the SiC substrate for superconductivity. In the Ca-intercalation process, at the interface a carbon layer terminating SiC changes to graphene by Ca-termination of SiC (monolayer graphene becomes a bilayer), inducing more electrons than a free-standing model. Then, Ca is intercalated in between the graphene layers, which shows superconductivity with the updated critical temperature (TC) of up to 5.7 K. In addition, the relation between TC and the normal-state conductivity is unusual, "dome-shaped". These findings are beyond the simple C6CaC6 model in which s-wave BCS superconductivity is theoretically predicted. This work proposes a general picture of the intercalation-induced superconductivity in graphene on SiC and indicates the potential for superconductivity induced by other intercalants.

Soft-Magnetic Skyrmions Induced by Surface-State Coupling in an Intrinsic Ferromagnetic Topological Insulator Sandwich Structure.

A magnetic skyrmion induced on a ferromagnetic topological insulator (TI) is a real-space manifestation of the chiral spin texture in the momentum space and can be a carrier for information processing by manipulating it in tailored structures. Here, a sandwich structure containing two layers of a self-assembled ferromagnetic septuple-layer TI, Mn(Bi1-xSbx)2Te4 (MnBST), separated by quintuple layers of TI, (Bi1-xSbx)2Te3 (BST), is fabricated and skyrmions are observed through the topological Hall effect in an intrinsic magnetic topological insulator for the first time. The thickness of BST spacer layer is crucial in controlling the coupling between the gapped topological surface states in the two MnBST layers to stabilize the skyrmion formation. The homogeneous, highly ordered arrangement of the Mn atoms in the septuple-layer MnBST leads to a strong exchange interaction therein, which makes the skyrmions "soft magnetic". This would open an avenue toward a topologically robust rewritable magnetic memory.

Efficacy and safety of cabazitaxel therapy in elderly (≥75 years) patients with castration-resistant prostate cancer: A multiinstitutional study.

BACKGROUND: There is little data on the outcome of cabazitaxel (CBZ) treatment of elderly patients with castration-resistant prostate cancer (CRPC). This study assessed the efficacy and safety of CBZ chemotherapy in patients with CRPC aged 75 years or older in a multiinstitutional study. METHODS: We retrospectively reviewed the 74 patients with CRPC treated with CBZ enrolled in 10 institutions. Clinicopathological backgrounds, prognosis including prostate-specific antigen decline, time to treatment failure, progression-free survival, overall survival, and safety profiles were compared between younger (<75 years) and elder (≥75 years) patients. RESULTS: In total, 74 patients were enrolled; 50 patients were younger than 75 years and 24 were ≥75 years. Clinicopathological characteristics were comparable between younger and elder patients, with the exception of serum albumin values at the time of CBZ treatment. The median prostate-specific antigen decline in younger and elder men was -8.8% and -32.3% from baseline, respectively. The median time to treatment failure, progression-free survival, and overall survival for younger and elder men were 0.24 and 0.33 years, 0.23 and 0.43 years, and 0.69 and 1.17 years, respectively. In addition, safety profiles were comparable between younger and elder patients. CONCLUSIONS: This multiinstitutional study suggests that patients with CRPC aged 75 years or older eligible for CBZ treatment can be treated safely and with noninferior efficacy compared with those younger than 75 years.

Prognostic Impact of Prior Androgen Receptor Axis-targeting Agents in Cabazitaxel Chemotherapy After Docetaxel.

BACKGROUND/AIM: The novel taxane cabazitaxel has been shown to exert excellent anticancer effects after androgen receptor axis-targeting (ARAT) agents in clinical data, but not in in vitro data. We investigated the clinical outcome of cabazitaxel chemotherapy after docetaxel according to use of ARAT agents. PATIENTS AND METHODS: Prostate specific antigen (PSA) response, progression-free survival, and overall survival were compared between cases with and without prior use of ARAT agents in 74 Japanese patients with metastatic castration-resistant prostate cancer treated with cabazitaxel chemotherapy. RESULTS: Background characteristics were comparable between patients with and without prior use of ARAT agents. PSA response, progression-free survival, and overall survival in cabazitaxel chemotherapy were comparable between patients with and without prior use of ARAT agents. CONCLUSION: No detrimental effects of prior ARAT agents on clinical outcome were observed for cabazitaxel chemotherapy in the post-docetaxel setting, suggesting that cabazitaxel can be expected to remain active even after ARAT agent therapy.

Prognostic significance of lactate dehydrogenase in cabazitaxel chemotherapy for castration-resistant prostate cancer: a multi-institutional study.

This multi-institutional study aimed to identify prognostic factors for cabazitaxel treatment of castration-resistant prostate cancer (CRPC). This study included 74 Japanese patients with CRPC who were treated with cabazitaxel between 2014 and 2017. Associations between clinicopathological factors including serum markers and progression-free survival (PFS) and overall survival (OS) were investigated. On multivariate analysis, high Gleason score [≥9 vs. ≤7; hazard ratio (HR), 95% confidence interval (CI): 2.00 (1.01-4.34); P = 0.047], presence of pain [HR, 95% CI: 2.02 (1.14-3.58); P = 0.016], and lactate dehydrogenase (LDH) level [HR, 95% CI: 47.31 (3.79-577.49); P = 0.0019] were significantly associated with PFS. Similarly, number of docetaxel cycles [HR, 95% CI: 0.050 (0.0037-0.45); P = 0.0057], performance status [≥2 vs. 0; HR, 95% CI: 5.07 (1.57-16.24); P < 0.0001], and LDH level [HR, 95% CI: 2946 (50-420994); P = 0.0001] were significantly associated with OS. This study showed that LDH level is robustly prognostic for both PFS and OS in cabazitaxel chemotherapy for CRPC.

Therapeutic Outcome of >10 Cycles of Cabazitaxel for Castration-resistant Prostate Cancer: A Multi-institutional Study.

BACKGROUND/AIM: Cabazitaxel use has usually been limited to up to 10 cycles in most countries according to the protocol in the TROPIC trial. Therefore, clinical data on cabazitaxel use beyond 10 cycles is limited. The aim of this study was to report the therapeutic outcome of cabazitaxel chemotherapy administered for >10 cycles. PATIENTS AND METHODS: This study included 74 Japanese patients with prostate cancer between 2014 and 2017. Patients background, and treatment outcomes including PSA decline, progression-free survival, treatment-failure-free survival, overall survival, and adverse events were investigated, comparing patients treated with ≤10 and >10 cycles. RESULTS: Patients characteristics were favorable as indicated by the higher number of cycles of prior docetaxel chemotherapy, absence of pain, and absence of bony and visceral metastases among men who received >10 cycles of cabazitaxel. PSA response, progression-free survival, treatment-failure-free survival and overall survival were better among patients treated with >10 cycles of cabazitaxel compared to those treated with ≤10 cycles. The incidence of severe adverse events was similar between the two groups. CONCLUSION: Taken together, this study suggested that continuous chemotherapy with cabazitaxel beyond 10 cycles may be beneficial.

Efficacy and safety of 4-weekly cabazitaxel for castration-resistant prostate cancer: a multi-institutional study.

OBJECTIVE: This study aimed to reveal the efficacy and safety profiles of 4-weekly cabazitaxel in patients with castration-resistant prostate cancer (CRPC). METHODS: The study included 62 Japanese patients who were treated for CRPC with ≥ 2 courses of cabazitaxel between 2014 and 2017. The oncological outcomes and adverse events were compared between 16 (25.8%) and 46 (74.2%) men who were treated with standard 3-weekly and alternative 4-weekly regimens, respectively. RESULTS: The prostate-specific antigen (PSA) response was comparable between the 3-weekly and 4-weekly regimens (median [interquartile range]: - 9.9% [- 64.5 to 13.0%] and - 30.7% [- 52.8 to 10.9%], P = 0.89), respectively. For patients on the 4-weekly regimen, the risks of progression (hazard ratio [HR], 95% confidence interval [CI] 1.27, 0.71-2.43, P = 0.44), treatment failure (HR, 95% CI 0.84, 0.48-1.55, P = 0.57) and any-cause mortality (HR, 95% CI 1.09, 0.58-2.17, P = 0.79) were comparable to those for patients on the 3-weekly regimen. The incidences of severe adverse events were also similar between the 3-weekly and 4-weekly regimens. CONCLUSIONS: 3-weekly and 4-weekly regimens of cabazitaxel showed similar efficacy and safety profiles in a real-world clinical setting. These data suggest that a 4-weekly regimen may be acceptable for selected patients.

Efficacy and safety of cabazitaxel for castration-resistant prostate cancer in patients with > 10 cycles of docetaxel chemotherapy: a multi-institutional study.

This multi-institutional study aimed to investigate the efficacy and safety profiles of cabazitaxel after prior docetaxel chemotherapy in patients with castration-resistant prostate cancer (CRPC). This study included 63 Japanese patients with CRPC who were treated with cabazitaxel from 2014 to 2017. The oncological outcomes and adverse events (AEs) were documented, and prognostic factors for oncological outcomes and predictive factors for AEs were analysed. PSA decline was observed in 68.3% of patients, including 25.4% who achieved a ≥ 50% decline. The median progression-free survival, treatment failure-free survival, and overall survival were 4.3, 4.1, and 9.0 months, respectively. More cycles of prior docetaxel therapy was identified as common favourable prognostic factors for progression-free survival, treatment failure-free survival, and overall survival. Severe neutropenia, febrile neutropenia, and severe non-haematological AEs were observed in 73.0%, 33.3%, and 23.8% of patients, respectively. However, > 10 cycles of docetaxel was not associated with increased incidence of AEs. In conclusion, cabazitaxel chemotherapy was still active in Japanese CRPC patients treated with > 10 cycles of docetaxel chemotherapy, with an acceptable risk of AE burden. Treatment with cabazitaxel after > 10 cycles of docetaxel may be an appropriate option when it can be administered.

Charge and spin transport on surfaces and atomic layers measured by multi-probe techniques.

Thanks to advances in in situ measurement techniques for electrical transport in ultra-high vacuum together with emergent materials such as Rashba-type surfaces, topological insulators, atomic-layer superconductors, and 2D materials like graphene, surface states and edge states on crystals provide intriguing topics, e.g. dissipation-less currents, spin-polarized electric current, and pure spin current. This is due to broken symmetry and strong spin-orbit and electron-phonon interactions. Here we review some examples of experimental techniques of multi-probe methods at macroscopic and microscopic scales, followed by transport phenomena revealed by them. These are opening a field in condensed matter physics driven by symmetry breaking at surfaces and atomic layers.

[A CASE OF RENAL CELL CARCINOMA THAT ONCE NIVOLUMAB HAD BEEN EFFECTIVE IN METASTATIC LESION AND MADE PRIMARY TUMOR RESECTABLE].

A 70-year-old woman, with an 8 cm tumor in the left kidney and multiple lung tumor and was diagnosed with Renal Cell Carcinoma (cT3aN0M1). The kidney tumor were unresectable and we started treatment with Tyrosine Kinase Inhibitors (sunitinib, pazopanib, axitinib, temsirolimus), but they failed because of disease progression or adverse events. We used nivolumab for 5th line treatment; then, interstitial pneumonia was observed. The renal tumor shrunk and pulmonary metastatic foci revealed prominent disappearance. The renal tumor became resectable and we tried nephrectomy. Pathological findings were clear cell carcinoma with marked necrosis, hyperplasia and internal bleeding.

Shubnikov-de Haas oscillations in p and n-type topological insulator (Bi x Sb1-x )2Te3.

We show Shubnikov-de Haas (SdH) oscillations in topological insulator (Bi x Sb1-x )2Te3 flakes whose carrier types are p-type (x = 0.29, 0.34) and n-type (x = 0.42). The physical properties such as the Berry phase, carrier mobility, and scattering time significantly changed by tuning the Fermi-level position with the concentration x. The analyses of SdH oscillations by Landau-level fan diagram, Lifshitz-Kosevich theory, and Dingle-plot in the p-type samples with x = 0.29 and 0.34 showed the Berry phase of zero and a relatively low mobility (2000-6000 cm2 V-1 s-1). This is due to the dominant bulk component in transport. On the other hand, the mobility in the n-type sample with x = 0.42 reached a very large value ~17 000 cm2 V-1 s-1 and the Berry phase of near π, whereas the SdH oscillations were neither purely two- nor three-dimensional. These suggest that the transport channel has a surface-bulk coupling state which makes the carrier scattering lesser and enhances the mobility and has a character between two- and three-dimension.

Large-Gap Magnetic Topological Heterostructure Formed by Subsurface Incorporation of a Ferromagnetic Layer.

Inducing magnetism into topological insulators is intriguing for utilizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) for technological applications. While most studies have focused on doping magnetic impurities to open a gap at the surface-state Dirac point, many undesirable effects have been reported to appear in some cases that makes it difficult to determine whether the gap opening is due to the time-reversal symmetry breaking or not. Furthermore, the realization of the QAHE has been limited to low temperatures. Here we have succeeded in generating a massive Dirac cone in a MnBi2Se4/Bi2Se3 heterostructure, which was fabricated by self-assembling a MnBi2Se4 layer on top of the Bi2Se3 surface as a result of the codeposition of Mn and Se. Our experimental results, supported by relativistic ab initio calculations, demonstrate that the fabricated MnBi2Se4/Bi2Se3 heterostructure shows ferromagnetism up to room temperature and a clear Dirac cone gap opening of ∼100 meV without any other significant changes in the rest of the band structure. It can be considered as a result of the direct interaction of the surface Dirac cone and the magnetic layer rather than a magnetic proximity effect. This spontaneously formed self-assembled heterostructure with a massive Dirac spectrum, characterized by a nontrivial Chern number C = -1, has a potential to realize the QAHE at significantly higher temperatures than reported up to now and can serve as a platform for developing future "topotronics" devices.

Superconducting Calcium-Intercalated Bilayer Graphene.

We report the direct evidence for superconductivity in Ca-intercalated bilayer graphene C6CaC6, which is regarded as the thinnest limit of Ca-intercalated graphite. We performed the electrical transport measurements with the in situ 4-point-probe method in ultrahigh vacuum under zero- or nonzero-magnetic field for pristine bilayer graphene, Li-intercalated bilayer graphene (C6LiC6) and C6CaC6 fabricated on SiC substrate. We observed that the zero-resistance state occurs in C6CaC6 with the onset temperature (T(c)(onset)) of 4 K, while the T(c)(onset) is gradually decreased upon applying the magnetic field. This directly proves the superconductivity origin of the zero resistance in C6CaC6. On the other hand, both pristine bilayer graphene and C6LiC6 exhibit nonsuperconducting behavior, suggesting the importance of intercalated atoms and its species to drive the superconductivity.

In situ magnetotransport measurements in ultrathin Bi films: evidence for surface-bulk coherent transport.

We performed in situ magnetotransport measurements on ultrathin Bi(111) films [4-30 bilayers (BLs), 16-120 Å thick] to elucidate the role of bulk or surface states in the transport phenomena. We found that the temperature dependence of the film conductivity shows no thickness dependence for the 6-16 BL films and is affected by the electron-electron scattering, suggesting surface-state dominant contribution. In contrast, the weak antilocalization effect observed by applying a magnetic field shows clear thickness dependence, indicating bulk transport. This apparent inconsistency is explained by a coherent bulk-surface coupling that produces a single channel transport. For the films thicker than 20 BLs, the behavior changes drastically which can likely be interpreted as a bulk dominant conduction.

Redox control and high conductivity of nickel bis(dithiolene) complex π-nanosheet: a potential organic two-dimensional topological insulator.

A bulk material comprising stacked nanosheets of nickel bis(dithiolene) complexes is investigated. The average oxidation number is -3/4 for each complex unit in the as-prepared sample; oxidation or reduction respectively can change this to 0 or -1. Refined electrical conductivity measurement, involving a single microflake sample being subjected to the van der Pauw method under scanning electron microscopy control, reveals a conductivity of 1.6 × 10(2) S cm(-1), which is remarkably high for a coordination polymeric material. Conductivity is also noted to modulate with the change of oxidation state. Theoretical calculation and photoelectron emission spectroscopy reveal the stacked nanosheets to have a metallic nature. This work provides a foothold for the development of the first organic-based two-dimensional topological insulator, which will require the precise control of the oxidation state in the single-layer nickel bisdithiolene complex nanosheet (cf. Liu, F. et al. Nano Lett. 2013, 13, 2842).

Magnetoresistance measurements of a superconducting surface state of in-induced and Pb-induced structures on Si(111).

In situ micro-four-point-probe conductivity measurements in ultrahigh vacuum revealed that the Si(111)-striped incommensurate-Pb surface showed the superconductivity transition at 1.1 K. Both of the hexagonal and rectangular phases of Si(111)√[7]×√[3]-In surface showed superconductivity at 2.4 and 2.8 K, respectively. By applying magnetic field perpendicular to the surface, the upper critical field was deduced to be 0.1-1 T. The derived Ginzburg-Landau coherence length of the Cooper pairs was several tens of nm, which was much smaller than the Pippard's coherence length estimated from the band structures. The short coherence length is determined by the carrier mean free path.