128 research outputs found

    Ferromagnetic shape memory alloy microwires

    Get PDF

    Surgical treatment of primary hepatic neuroendocrine tumor diagnosed by Al18F-NOTA-Octreotide PET/CT: a case report

    Get PDF
    Neuroendocrine tumors (NETs) are a heterogeneous group of tumors originating from peptide-producing neurons and neuroendocrine cells. The liver is the most common site of metastasis for NETs, while primary hepatic neuroendocrine tumors (PHNETs) are exceedingly rare. While somatostatin receptor scintigraphy (SRS) has demonstrated superior efficacy compared to [18F]FDG PET imaging in the diagnosis of neuroendocrine tumors, [18F]AlF-NOTA-Octreotide ([18F]AlF-OC) PET/CT also exhibits specific advantages over SRS. This article presents a case study of a patient with a liver mass who underwent sequential [18F]FDG and [18F]AlF-OC PET/CT scans, ruling out hepatocellular carcinoma and confirming the diagnosis of PHNETs. Subsequently, the patient underwent surgical treatment. From another perspective, [18F]AlF-OC exhibits distinct advantages. The postoperative pathology revealed a PHNETs, which further emphasizes its clinical rarity

    Semidiscrete optical vortex droplets in quasi-phase-matched photonic crystals

    Full text link
    A new scheme for producing semidiscrete self-trapped vortices (\textquotedblleft swirling photon droplets\textquotedblright ) in photonic crystals with competing quadratic (χ(2)\chi ^{(2)}) and self-defocusing cubic (χ(3)\chi ^{(3)}) nonlinearities is proposed. The photonic crystal is designed with a striped structure, in the form of spatially periodic modulation of the χ(2)\chi ^{(2)} susceptibility, which is imposed by the quasi-phase-matching technique. Unlike previous realizations of semidiscrete optical modes in composite media, built as combinations of continuous and arrayed discrete waveguides, the semidiscrete vortex droplets are produced here in the fully continuous medium. This work reveals that the system supports two types of semidiscrete vortex droplets, \textit{viz}., onsite- and intersite-centered ones, which feature, respectively, odd and even numbers of stripes, N\mathcal{N}. Stability areas for the states with different values of N\mathcal{N} are identified in the system's parameter space. Some stability areas overlap with each others, giving rise to multistability of states with different N\mathcal{N}. The coexisting states are mutually degenerate, featuring equal values of the Hamiltonian and propagation constant. An experimental scheme to realize the droplets is outlined, suggesting new possibilities for the long-distance transmission of structured light carrying orbital angular momentum in nonlinear media.Comment: 9 pages, 7 figures, and 82 reference

    Case Report: Camrelizumab combined with gemcitabine and oxaliplatin in the treatment of advanced intrahepatic cholangiocarcinoma: a case report and literature review

    Get PDF
    Intrahepatic cholangiocarcinoma (ICC) is one of the most common invasive malignant tumors, with a 5-year survival rate of less than 5%. Currently, radical surgical resection is the preferred treatment for ICC. However, most patients are only diagnosed at an advanced stage and are therefore not eligible for surgery. Herein, we present a case of advanced ICC in which radical surgery was not possible due to tumor invasion of the second porta hepatis and right hepatic artery. Six treatment cycles with a gemcitabine and oxaliplatin (GEMOX) regimen combined with camrelizumab immunotherapy achieved a partial response and successful tumor conversion, as tumor invasion of the second porta hepatis and right hepatic artery was no longer evident. The patient subsequently underwent successful radical surgical resection, including hepatectomy, caudate lobe resection, and cholecystectomy combined with lymph node dissection. Cases of patients with advanced ICC undergoing surgical resection after combined immunotherapy and chemotherapy are rare. The GEMOX regimen combined with camrelizumab demonstrated favorable antitumor efficacy and safety, suggesting that it might be a potential feasible and safe conversion therapy strategy for patients with advanced ICC

    Indigo: a natural molecular passivator for efficient perovskite solar cells

    Get PDF
    Organic–inorganic hybrid lead halide perovskite solar cells have made unprecedented progress in improving photovoltaic efficiency during the past decade, while still facing critical stability challenges. Herein, the natural organic dye Indigo is explored for the first time to be an efficient molecular passivator that assists in the preparation of high-quality hybrid perovskite film with reduced defects and enhanced stability. The Indigo molecule with both carbonyl and amino groups can provide bifunctional chemical passivation for defects. In-depth theoretical and experimental studies show that the Indigo molecules firmly binds to the perovskite surfaces, enhancing the crystallization of perovskite films with improved morphology. Consequently, the Indigo-passivated perovskite film exhibits increased grain size with better uniformity, reduced grain boundaries, lowered defect density, and retarded ion migration, boosting the device efficiency up to 23.22%, and ˜21% for large-area device (1 cm2). Furthermore, the Indigo passivation can enhance device stability in terms of both humidity and thermal stress. These results provide not only new insights into the multipassivation role of natural organic dyes but also a simple and low-cost strategy to prepare high-quality hybrid perovskite films for optoelectronic applications based on Indigo derivatives.Peer ReviewedPostprint (author's final draft

    Selection response and estimation of the genetic parameters for multidimensional measured breast meat yield related traits in a long-term breeding Pekin duck line

    Get PDF
    Objective This study was conducted to estimate the genetic parameters and breeding values of breast meat related traits of Pekin ducks. Selection response was also determined by using ultrasound breast muscle thickness (BMT) measurements in combination with bosom breadth (BB) and keel length (KL) values. Methods The traits analyzed were breast meat weight (BMW), body weight (BW), breast meat percentage (BMP) and the three parameters of breast meat (BB, KL, and BMT). These measurements were derived from studying 15,781 Pekin ducks selected from 10 generations based on breast meat weight. Genetic parameters and breeding value were estimated for the analysis of the breeding process. Results Estimated heritability of BMW and BMP were moderate (0.23 and 0.16, respectively), and heritability of BW was high (0.48). Other traits such as BB, KL, and BMT indicated moderate heritability ranging between 0.11 and 0.28. Significant phenotypic correlations of BMW with BW and BMP were discovered (p<0.05), and genetic correlations of BMW with BW and BMP were positive and high (0.83 and 0.66, respectively). It was noted that BMW had positive correlations with all the other traits. Generational average estimated breeding values of all traits increased substantially over the course of selection, which demonstrated that the ducks responded efficiently to increased breast meat yield after 10 generations of breeding. Conclusion The results indicated that duck BMW had the potential to be increased through genetic selection with positive effects on BW and BMP. The ultrasound BMT, in combination with the measurement of BB and KL, is shown to be essential and effective in the process of high breast meat yield duck breeding

    Resistive switching phenomena in stacks of binary transition metal oxides grown by atomic layer deposition

    No full text
    Information technology is approaching the era of artificial intelligence. New computing architectures are required to cope with the huge amount of data that has to be processed in all types of cognitive applications. This requires dedicated energy efficient solutions on the level of the computing hardware. The new concepts of neuromorphic computing (NC), like artificial neural networks (ANNs) and computation in memory (CIM), aim to overcome the limitations of classical computers based on von Neumann architecture. Redox-type resistive random access memory (ReRAM) devices are intensively investigated for NC applications due to their non-volatility and energy efficiency, process compatibility with standard complementary metal oxide semiconductor (CMOS) technology, and the ability for device scaling and three-dimensional (3D) integration. The variety of applications requests for different desired properties of the ReRAM devices ranging from an analog-type programmable multilevel behavior to a binary-type switching at high resistance ratio and with linear resistance states. ReRAM research today focuses on devices built of metal oxide layers with nano-meter thickness sandwiched between a chemically inert electrode like Pt or TiN and a chemically reactive electrode. The precise thickness control is achieved by vapor phase deposition techniques, in particular, atomic layer deposition (ALD). However, some basic issues like switching stability and resistance variability are still obstacles on the way towards massive integration. One of the efforts to improve the device performance is the use of combinations of two metal oxides layers, so called bilayer oxide stacks. The two different metal oxide layers are selected regarding their insulation resistance and oxidation enthalpy. Here, especially the bilayer ReRAM stack of TiO2 and Al2O3 has drawn attention of researches worldwide. TiO2 belongs to the materials integrated into ReRAM devices since the early start in the beginning of this millennium. However, most of the single-layer TiO2 devices lack stability in the standard valence change mechanism (VCM)-type filamentary switching behavior and suffer from a too high residual leakage current. One approach for improvement is the addition of an Al2O3 barrier layer into the TiO2 ReRAM device. So far, in the scientific literature, there is no clear consensus if this type of Al2O3/TiO2 bilayer cells reveal a standard VCM-type filamentary switching or an area-dependent switching behavior. The present study aims at a clarification of different phenomena associated with the bipolar resistive switching in bilayer ReRAM devices built from Al2O3 and TiO2 layers. In order to cope with device sizes, which are close to the industrial scale, nano-crossbar ReRAM cells were fabricated with an electrode area of (60 nm)2 to (100 nm)2 and oxide layer thickness below 10 nm. Nanometer-thin, dense oxide layers of reproducible quality were grown by means of ALD. Here a Pt bottom electrode was used as the Schottky electrode. In contrast, for the Pt/oxide/metal structures the metal top electrode was varied between Ti and TiN. A systematic study was performed regarding the effect of the resistive switching oxide comparing single-layers of Al2O3 and TiO2 and bilayers with different stack sequence, this means, Al2O3/TiO2 and TiO2/Al2O3. Study of the electroforming behavior in the various device stacks Pt/Al2O3/Pt cells reveals the identical breakdown strength as observed for other reported Al2O3 single-layer devices. In contrast, Pt/Al2O3/Ti devices show a linear dependence of the electroforming voltage for the Al2O3 thickness of 2 to 5 nm. Pt/TiO2/Ti devices are conductive in their initial state for TiO2 thickness below 10 nm. In bilayer stacks the electroforming voltage is dominated by the thickness of the Al2O3 layer, but the additional TiO2 layer is not negligible. According to the different oxidation enthalpies, the use of a Ti electrode results in a more reproducible and stable switching compared to TiN. Pt/metal oxide/Ti nano-crossbar devices with a thin Al2O3 layer show filamentary VCM-type counter-eightwise (c8w) bipolar resistive switching after successful electroforming and first RESET step. The resistance ratio is controlled by choosing values of current compliance and RESET stop voltage between high and low resistance state, respectively. Deep RESET behavior is obtained for the Al2O3 film thicker than 4 nm. However, effects appear which are attributed to a filling of trap states in the Al2O3 layer adjacent to the Pt Schottky electrode. The charge transport behavior of the different cells was systematically analyzed considering the voltage and temperature dependence of the initial state, the high (HRS) and low resistance state (LRS). The current transport in the insulating devices, i.e. Al2O3 and the bilayers with Al2O3, was successfully simulated by the Simmons' equation for tunneling through a trapezoidal barrier. This also holds for the HRS state with differences in tunneling barrier and tunneling area. The area of 100 nm2 attributed to the HRS fits well to the physical diameter of the filament of about 10 nm that was determined from the crystallized regime appearing in the cross-section of a switched device via transmission electron microscopy. For all devices the LRS exhibits an almost metallic-type conduction characteristic. Pulse switching analysis leads to a SET kinetic, which is well described by the ion hopping model utilizing Mott-Gurney law for oxygen vacancy drift.Pt/TiO2/Ti nano-crossbar devices show an extraordinary behavior of the coexistence of standard filamentary counter-eightwise (c8w) and stable eightwise (8w) switching at significantly reduced currents. The two switching modes with opposite polarity share a common state, this is, the c8w HRS equals the 8w LRS*. A model is proposed which describes this coexistence as a competition between oxygen vacancy drift/diffusion and oxygen incorporation/extraction at the Pt/TiO2-x interface. The reduced/increased amount of oxygen vacancies in the regime of the conductive filament's disc leads to a band bending and a change of the parabolic shaped tunneling barrier at the switching interface. In the Pt/TiO2/Ti nano-devices the 8w-switching process occurs at switching voltages of about 2 V, but at a significantly reduced current level with resistance values of about Mega- and Giga-Ohm in LRS* and HRS*, respectively. The deeper understanding of switching phenomena and conduction behavior in the various Al2O3 and TiO2 single-layer and bilayer nano-crossbar devices can be utilized for improvement of existing switching models and for future cell design addressing particular applications
    • …
    corecore