Negative Reflection and Negative Refraction in Biaxial van der Waals Materials.

Negative reflection and negative refraction are exotic phenomena that can be achieved by platforms such as double-negative metamaterial, hyperbolic metamaterial, and phase-discontinuity metasurface. Recently, natural biaxial van der Waals (vdW) materials, which support extremely anisotropic, low-loss, and highly confined polaritons from infrared to visible regime, are emerging as promising candidates for planar reflective and refractive optics. Here, we introduce three degrees of freedom, namely interface, crystal direction, and electric tunability, to manipulate the reflection and refraction of the polaritons. With broken in-plane symmetry contributed by the interface and crystal direction, distinguished reflection, and refraction such as negative and backward reflection, positive and negative refraction could exist simultaneously and exhibit high tunability. The numerical simulations show good consistency with the theoretical analysis. Our findings provide a robust recipe for the realization of negative reflection and refraction in biaxial vdW materials, paving the way for the polaritonics and on-chip integrated circuits.

Bowtie loaded meander antenna for a high-temperature superconducting terahertz detector and its characterization by the Josephson effect.

In a quasi-optical system, the high temperature superconducting terahertz detector often suffers from a fundamental problem of low coupling efficiency with the terahertz signal, especially for the detector based on YBa2Cu3O7-δ (YBCO) bicrystal Josephson junction (JJ) due to a small normal-state resistance. Here, we developed a bowtie loaded meander antenna to enhance coupling efficiency. Differing from the conventional characterization confining on vector network analyzers, we applied three methods to evaluate the antenna, including the measurements of the maximal size of the first order Shapiro step under per incident power, the coupling efficiency between the antenna and the junction, and voltage responsivity. Furthermore, with simulation analysis, we propose that the inductive reactance of the YBCO bicrystal JJ is around 60 ohms under terahertz irradiation at 210 GHz, thus, the reactance is comparable as that of the antenna.

Prolonging Gastrointestinal-Stromal-Tumor-free life, an optimal suggestion of imatinib intervention ahead of operation.

Background: Imatinib has been regarded as the first successful synthetic small molecule targeting at blocking tyrosine kinase. Its high efficacy stabilized disease in above 80% of chronic myeloid leukemia (CML) patients over 10 years survival. Due to the similar canceration of gastrointestinal stromal tumor (GIST) as to CML, imatinib has been approved to be used as first-line treatment. Study design: Our retrospective study was proposed to enroll 191 GIST patients with larger tumor size (≥8 cm) who preoperative accepted imatinib from those with direct operation. Analysis included demographics, cancer specific survival and relationship of their risk factors. Results: Male patients and gastrointestinal (GI) tract location took higher proportion in total cases, detection of KIT mutant took 89.7% among all traceable genetic testing. Patients with preoperative imatinib can achieve higher cancer specific survival (CSS) after both in 1 year and 3 years duration than their counterpart. Tumor size above its threshold of 8 cm would be a hazardous factor for poor prognosis. Conclusion: In conclusion, as for regressing tumor progression and creating operative chance, preoperative imatinib should be considered for the patients with high risk, although the precise duration of this intervention needs further validation.

Independent Mobility Achieved through a Wireless Brain-Machine Interface.

Individuals with tetraplegia lack independent mobility, making them highly dependent on others to move from one place to another. Here, we describe how two macaques were able to use a wireless integrated system to control a robotic platform, over which they were sitting, to achieve independent mobility using the neuronal activity in their motor cortices. The activity of populations of single neurons was recorded using multiple electrode arrays implanted in the arm region of primary motor cortex, and decoded to achieve brain control of the platform. We found that free-running brain control of the platform (which was not equipped with any machine intelligence) was fast and accurate, resembling the performance achieved using joystick control. The decoding algorithms can be trained in the absence of joystick movements, as would be required for use by tetraplegic individuals, demonstrating that the non-human primate model is a good pre-clinical model for developing such a cortically-controlled movement prosthetic. Interestingly, we found that the response properties of some neurons differed greatly depending on the mode of control (joystick or brain control), suggesting different roles for these neurons in encoding movement intention and movement execution. These results demonstrate that independent mobility can be achieved without first training on prescribed motor movements, opening the door for the implementation of this technology in persons with tetraplegia.

E2F-1 promotes DAPK2-induced anti-tumor immunity of gastric cancer cells by targeting miR-34a.

Activation of the transcription factor E2F-1 gene is a negative event in dendritic cell (DC) maturation process. Down-regulation of E2F1 causes immaturity of DC thereby stopping antigen production which in turn leads to inhibition of immune responses. E2F-1-free stimulates the NF-kB signaling pathway, leading to activation of monocytes and several other transcription factor genes. In the study, we report that down-regulation of E2F-1 in DCs promote anti-tumor immune response in gastric cancer (GC) cells through a novel mechanism. DCs were isolated from peripheral blood mononuclear cells. E2F-1 small interfering RNA (E2F-1-shRNA) induced down-regulation of E2F-1 mRNA and protein expression in DCs. Furthermore, we identified the E2F-1-shRNA targeted the CD80, CD83, CD86, and MHC II molecules, promoted their expression, and induced T lymphocytes proliferation activity and up-regulation of IFN-I³ production and GC cell killing effect, which significantly correlated with the cytotoxic T lymphocytes activated by E2F-1-shRNA DCs. The higher expression of miR-34a was found which was significantly correlated with the DC enhancing anti-tumor immunity against gastric cancer cell, and miR-34a potently targeted DAPK2 and Sp1, both of which were involved in the deactivation of E2F-1. Moreover, in E2F-1-DC-down-regulation in mice, GC transplantation tumors displayed down-regulation of Sp1, DAPK2, Caspase3, and Caspase7 and progressed to anti-tumor immunity. Collectively, our data uncover an E2F-1-mediated mechanism for the control of DC anti-tumor immunity via miR-34a-dependent down-regulation of E2F-1 expression and suggest its contribution to GC immunotherapy.

miR-135a promotes gastric cancer progression and resistance to oxaliplatin.

Resistance to oxaliplatin (OXA)-based chemotherapy regimens continues to be a major cause of gastric cancer (GC) recurrence and metastasis. We analyzed GC samples and matched non-tumorous control stomach tissues from 280 patients and found that miR-135a was overexpressed in GC samples relative to control tissues. Tumors with high miR-135a expression were more likely to have aggressive characteristics (high levels of carcino-embryonic antigen, vascular invasion, lymphatic metastasis, and poor differentiation) than those with low levels. Patients with greater tumoral expression of miR-135a had shorter overall survival times and times to disease recurrence. Furthermore, miR-135a, which promotes the proliferation and invasion of OXA-resistant GC cells, inhibited E2F transcription factor 1 (E2F1)-induced apoptosis by downregulating E2F1 and Death-associated protein kinase 2 (DAPK2) expression. Our results indicate that higher levels of miR-135a in GC are associated with shorter survival times and reduced times to disease recurrence. The mechanism whereby miR-135a promotes GC pathogenesis appears to be the suppression of E2F1 expression and Sp1/DAPK2 pathway signaling.

Consumptive hypothyroidism due to a gastrointestinal stromal tumor expressing type 3 iodothyronine deiodinase.

CONTEXT: Gastrointestinal stromal tumors (GISTs) are responsive to sunitinib (the tyrosine kinase inhibitor), this agent is widely used in prevention relapse of GISTs and neo-adjuvant chemotherapy in GIST patients without operation opportunity. The use of these agents has both advantages and disadvantages. On the one hand, it can improve the outcome for patient. On the other hand, it may lead to consumptive hypothyroidism, a rare syndrome caused by increased catabolism of T4 and T3 by increased type 3 iodothyronine deiodinase (D3) activity. D3 is the major physiologic inactivator of thyroid hormone, this selenoenzyme catalyzes the inner-ring deiodination of T(4) to reverse T(3) and T(3) to 3, 3;-diiodothyronine, both of which are biologically inactive [1]. Increased monitoring and supernormal thyroid hormone supplementation are required for affected patient. OBJECTIVE: The aim of the study was to report the first case of consumptive hypothyroidism in an athyreotic patient after surgical resection of gastrointestinal stromal tumor. DESIGN, SETTING, AND PATIENT: A 60-year-old athyreotic male was presented and he was euthyroid when receiving a stable therapeutic dose of thyroid hormone which was used to treat consumptive hypothyroidism resulting from the side effects of sunitinib, which is used for treatment of neo-adjuvant chemotherapy in gastrointestinal stromal tumor. With a discovery of large D3-expressing gastrointestinal stromal tumor, this patient suffered from marked Hyperthyrotropinemia, which instantly worsened after surgical resection of the gastrointestinal stromal tumor and then continued for 12 weeks after the surgical resection, in spite of further increases in levothyroxine therapy. The patient also had low serum T3 and elevated serum reverse T3 (rT3). INTERVENTION: The patient's consumptive hypothyroidism caused by marked overexpression of the thyroid hormone-inactivating D3 within the gastrointestinal stromal tumor and adjacent normal gastrointestinal tissue. MAIN OUTCOME MEASURES AND RESULTS: D3 immunostaining of the patient's gastrointestinal stromal tumor was positive, with no significant immunoreactivity in adjacent normal gastrointestinal tissue. The expression levels of CD34, CD117, and DOG1 in peri-tumor tissue samples was lower than that in tumor tissue. The mRNA expression level of KIT exon17 in peri-tumor tissue was higher than that in tumor tissue. CONCLUSIONS: This is the first case report of consumptive hypothyroidism in an adult after surgical partial resection of the gastrointestinal stromal tumor. This case demonstrates that hyperthyrotropinemia may worsen after surgical resection of the gastrointestinal stromal tumor.

Manipulation of acoustic focusing with an active and configurable planar metasurface transducer.

It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area. However, previous researches seldom consider the focal resolution, whose focal size is much larger than one wavelength. Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns. Here, an active and configurable planar metasurface PT prototype is proposed to manipulate the acoustic focal pattern and the focal resolution freely. By suitably optimized ring configurations of the active metasurface PT, we demonstrate the manipulation of focal patterns in acoustic far fields, such as the designed focal needle and multi foci. Our method is also able to manipulate and improve the cross-sectional focal resolution from subwavelength to the extreme case: the deep sub-diffraction-limit resolution. Via the acoustic Rayleigh-Sommerfeld diffraction integral (RSI) cum the binary particle swarm optimization (BPSO), the free manipulation of focusing properties is achieved in acoustics for the first time. Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.

Split-step finite-difference time-domain method with perfectly matched layers for efficient analysis of two-dimensional photonic crystals with anisotropic media.

This Letter presents a split-step (SS) finite-difference time-domain (FDTD) method for the efficient analysis of two-dimensional (2-D) photonic crystals (PhCs) with anisotropic media. The proposed SS FDTD method is formulated with perfectly matched layer boundary conditions and caters for inhomogeneous anisotropic media. Furthermore, the proposed method is derived using the efficient SS1 splitting formulas with simpler right-hand sides that are more efficient and easier to implement. A 2-D PhC cavity with anisotropic media is used as an example to validate the efficiency of the proposed method.

Modeling magnetic photonic crystals with lossy ferrites using an efficient complex envelope alternating-direction-implicit finite-difference time-domain method.

In this Letter, we present an efficient complex-envelope alternating-direction-implicit finite-difference time-domain (CE-ADI-FDTD) method for the transient analysis of magnetic photonic crystals with lossy ferrites. The proposed CE-ADI-FDTD method is generally formulated for a saturated ferrite with anisotropic permittivity tensor and ferrite loss. Auxiliary differential equations for modeling saturated ferrite and Maxwell's curl equations are first cast into a first-order differential system in a CE form. Then, by using an efficient ADI splitting formulas, the proposed CE-ADI-FDTD method is attained in a very concise form with few and simple right-hand side terms. The performance of the proposed method is validated and compared with the explicit FDTD method.