A predictive scoring model to select suitable patients for surgery on primary tumor in metastatic esophageal cancer.

BACKGROUND: Surgery on primary tumor (SPT) has been a common treatment strategy for many types of cancer. AIMS: This study aimed to investigate whether SPT could be considered a treatment option for metastatic esophageal cancer and to identify the patient population that would benefit the most from SPT. METHODS: Data from 18 registration sites in the Surveillance, Epidemiology, and End Results Program database (SEER database) were analyzed to select patients with metastatic esophageal cancer. Multivariate Cox regression analysis was used to identify potential risk factors for pre-treatment survival. Variables with a p-value of less than 0.05 were used to construct a pre-treatment nomogram. A pre-surgery predictive model was then developed using the pre-surgery factors to score patients, called the "pre-surgery score". The optimal cut-off value for the "pre-surgery score" was determined using X-tile analysis, and patients were divided into high-risk and low-risk subsets. It was hypothesized that patients with a low "pre-surgery score" risk would benefit the most from SPT. RESULTS: A total of 3793 patients were included in the analysis. SPT was found to be an independent risk factor for the survival of metastatic esophageal cancer patients. Subgroup analyses showed that patients with liver or lung metastases derived more benefit from SPT compared to those with bone or brain metastases. A pre-treatment predictive model was constructed to estimate the survival rates at one, two, and three years, which showed good accuracy (C-index: 0.705 for the training set and 0.701 for the validation set). Patients with a "pre-surgery score" below 4.9 were considered to have a low mortality risk and benefitted from SPT (SPT vs. non-surgery: median overall survival (OS): 24 months vs. 4 months, HR = 0.386, 95% CI: 0.303-0.491, p < 0.001). CONCLUSION: This study demonstrated that SPT could improve the OS of patients with metastatic esophageal cancer. The pre-treatment scoring model developed in this study might be useful in identifying suitable candidates for SPT. The strengths of this study include the large patient sample size and rigorous statistical analyses. However, limitations should be noted due to the retrospective study design, and prospective studies are needed to validate the findings in the future.

Undoped Strained Ge Quantum Well with Ultrahigh Mobility of Two Million.

We develop a method to fabricate an undoped Ge quantum well (QW) under a 32 nm relaxed Si0.2Ge0.8 shallow barrier. The bottom barrier contains Si0.2Ge0.8 (650 °C) and Si0.1Ge0.9 (800 °C) such that variation of Ge content forms a sharp interface that can suppress the threading dislocation density (TDD) penetrating into the undoped Ge quantum well. The SiGe barrier introduces enough in-plane parallel strain (ε∥ strain -0.41%) in the Ge quantum well. The heterostructure field-effect transistors with a shallow buried channel obtain an ultrahigh two-dimensional hole gas (2DHG) mobility over 2 × 106 cm2/(V s) and a very low percolation density of (5.689 ± 0.062) × 1010 cm-2. The fractional indication is also observed at high density and high magnetic fields. This strained germanium as a noise mitigation material provides a platform for integration of quantum computation with a long coherence time and fast all-electrical manipulation.

Development of a risk model based on immune genes in patients with colon adenocarcinoma.

BACKGROUND: The rapidly increasing morbidity and the poor prognosis making the colon adenocarcinoma not only common but also highly malignant. On the other hand, immunotherapy emerges as a therapeutic modality of colon cancer recently. In this study, we developed a prognostic risk model that is based on immune genes, which could predict the overall survival (OS) of patients with colon adenocarcinoma. METHODS: The Cancer Genome Atlas (TCGA) database was used to download both transcriptomic and clinical data, and the ImmPort database was used to obtain immune genes. The least absolute shrinkage and selection operator (LASSO)-Cox regression was adopted to further select the key genes with prognostic value. Then the key genes were inputted into stepwise regression to calculated each patient's immune-related risk score (immune score). Survival, survminer packages and bilateral tests in R language were adopted to determine the optimal cut-off value (cut-off value) for the risk score. This threshold divides patients into immune-score high-risk and low-risk groups. The differences in the levels of infiltrating immune cells and stromal cells in the high and low immune risk groups were then calculated and compared by the CIBERSORT algorithm. RESULTS: According to our results, a prognostic risk model was constructed based upon 26 immune-related genes. High immune score was shown to be a poor prognostic factor for colon adenocarcinoma patients, such as overall survival, progress free survival for different therapies, and tumor stages. High immune score was also associated with the abundance of CD4+ T cells and CD8+ T cells. In addition, the high immune score group, the expression levels of LMTK3, LAG3 and PD-L1 were higher than those in the low score group. CONCLUSION: We developed a 26-immune gene model of colon adenocarcinoma to predict patient's survival. This model might be used in clinical practice as a prognostic instrument for patients diagnosed with colon adenocarcinoma.

CD274 (PD-L1) Methylation is an Independent Predictor for Bladder Cancer Patients' Survival.

This study was carried out to demonstrate the prognostic value of CD274 (PD-L1 promoter gene) methylation in bladder cancer patients. UCSC Xena database was searched for relevant information on PD-L1 (CD274) methylation and PD-L1 mRNA expression in bladder cancer. 407 bladder patients were included in our analyses. Multivariate analysis revealed that PD-L1 methylation was an independent predictor for OS (P = 0.037). Moreover, PD-L1 methylation might be a prognostic biomarker for immunotherapy response. However, PD-L1 methylation and PD-L1 mRNA expression was not statistically associated with chemotherapy response. In conclusion, PD-L1 methylation was an independent prognostic factor for bladder cancer patients.

Flatbands and Emergent Ferromagnetic Ordering in Fe_{3}Sn_{2} Kagome Lattices.

A flatband representing a highly degenerate and dispersionless manifold state of electrons may offer unique opportunities for the emergence of exotic quantum phases. To date, definitive experimental demonstrations of flatbands remain to be accomplished in realistic materials. Here, we present the first experimental observation of a striking flatband near the Fermi level in the layered Fe_{3}Sn_{2} crystal consisting of two Fe kagome lattices separated by a Sn spacing layer. The band flatness is attributed to the local destructive interferences of Bloch wave functions within the kagome lattices, as confirmed through theoretical calculations and modelings. We also establish high-temperature ferromagnetic ordering in the system and interpret the observed collective phenomenon as a consequence of the synergetic effect of electron correlation and the peculiar lattice geometry. Specifically, local spin moments formed by intramolecular exchange interaction are ferromagnetically coupled through a unique network of the hexagonal units in the kagome lattice. Our findings have important implications to exploit emergent flat-band physics in special lattice geometries.

Atomically flat and thermally stable graphene on Si(111) with preserved intrinsic electronic properties.

Silicon and graphene are two wonder materials, and their hybrid heterostructures are expected to be very interesting fundamentally and practically. In the present study, by adopting fast dry transfer and ultra-high vacuum annealing, atomically flat monolayer graphene is successfully prepared on the chemically active Si(111) substrate. More importantly, the graphene overlayer largely maintains its intrinsic electronic properties, as validated by the results of the energy-dependent electronic transparency, Dirac point observation and quantum coherence characteristics, and further confirmed by first-principles calculations. The intrinsic properties of graphene are retained up to 1030 K. The system of atomically flat and thermally stable graphene on a chemically active silicon surface with preserved inherent characteristics renders the graphene/silicon hybrid a promising system in the design of high-performance devices and the exploitation of interfacial topological quantum effects.

Quantum Control of Graphene Plasmon Excitation and Propagation at Heaviside Potential Steps.

Quantum mechanical effects of single particles can affect the collective plasmon behaviors substantially. In this work, the quantum control of plasmon excitation and propagation in graphene is demonstrated by adopting the variable quantum transmission of carriers at Heaviside potential steps as a tuning knob. First, the plasmon reflection is revealed to be tunable within a broad range by varying the ratio γ between the carrier energy and potential height, which originates from the quantum mechanical effect of carrier propagation at potential steps. Moreover, the plasmon excitation by free-space photos can be regulated from fully suppressed to fully launched in graphene potential wells also through adjusting γ, which defines the degrees of the carrier confinement in the potential wells. These discovered quantum plasmon effects offer a unified quantum-mechanical solution toward ultimate control of both plasmon launching and propagating, which are indispensable processes in building plasmon circuitry.

Optical Manipulation of Rashba Spin-Orbit Coupling at SrTiO3-Based Oxide Interfaces.

Spin-orbit coupling (SOC) plays a crucial role for spintronics applications. Here we present the first demonstration that the Rashba SOC at the SrTiO3-based interfaces is highly tunable by photoinduced charge doping, that is, optical gating. Such optical manipulation is nonvolatile after the removal of the illumination in contrast to conventional electrostatic gating and also erasable via a warming-cooling cycle. Moreover, the SOC evolutions tuned by illuminations with different wavelengths at various gate voltages coincide with each other in different doping regions and collectively form an upward-downward trend curve: In response to the increase of conductivity, the SOC strength first increases and then decreases, which can be attributed to the orbital hybridization of Ti 3d subbands. More strikingly, the optical manipulation is effective enough to tune the interferences of Bloch wave functions from constructive to destructive and therefore to realize a transition from weak localization to weak antilocalization. The present findings pave a way toward the exploration of photoinduced nontrivial quantum states and the design of optically controlled spintronic devices.

Substantially Enhancing Quantum Coherence of Electrons in Graphene via Electron-Plasmon Coupling.

The interplays between different quasiparticles in solids lay the foundation for a wide spectrum of intriguing quantum effects, yet how the collective plasmon excitations affect the quantum transport of electrons remains largely unexplored. Here we provide the first demonstration that when the electron-plasmon coupling is introduced, the quantum coherence of electrons in graphene is substantially enhanced with the quantum coherence length almost tripled. We further develop a microscopic model to interpret the striking observations, emphasizing the vital role of the graphene plasmons in suppressing electron-electron dephasing. The novel and transformative concept of plasmon-enhanced quantum coherence sheds new insight into interquasiparticle interactions, and further extends a new dimension to exploit nontrivial quantum phenomena and devices in solid systems.