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Yan Liu, Jiebin Niu, Hongjuan Wang, Genquan Han, Chunfu Zhang, Qian Feng, Jincheng Zhang, Yue Hao
Well-behaved Ge quantum well (QW) p-channel metal-oxide-semiconductor field-effect transistors (pMOSFETs) were fabricated on silicon-on-insulator (SOI) substrate. By optimizing the growth conditions, ultrathin fully strained Ge film was directly epitaxially grown on SOI at about 450 °C using ultra-high vacuum chemical vapor deposition. In situ Si2H6 passivation of Ge was utilized to form a high-quality SiO2/Si interfacial layer between the high-κ dielectric and channels. Strained Ge QW pMOSFETs achieve the significantly improved effective hole mobility μ eff as compared with the relaxed Si and Ge control devices...
December 2017: Nanoscale Research Letters
Arathi Sreekumari, K S Shriram, Vivek Vaidya, Arathi Sreekumari, K S Shriram, Vivek Vaidya, Vivek Vaidya, K S Shriram, Arathi Sreekumari
Automated Breast Ultrasound (ABUS) is highly effective as breast cancer screening adjunct technology. Automation can greatly enhance the efficiency of the clinician sifting through the quantum of data in ABUS volumes to spot lesions. We have implemented a fully automatic generic algorithm pipeline for detection and characterization of lesions on such 3D volumes. We compare a wide range of features for region description on their effectiveness at the dual goals of lesion detection and characterization. On multiple feature images, we compute region descriptors at lesion candidate locations obviating the need for explicit lesion segmentation...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
N Rawat, Y Shin, I Balasingham, N Rawat, Y Shin, I Balasingham, I Balasingham, N Rawat, Y Shin
An electroencephalogram (EEG) based image encryption combined with Quantum walks (QW) is encoded in Fresnel domain. The computational version of EEG randomizes the original plaintext whereas QW can serve as an excellent key generator due to its inherent nonlinear chaotic dynamic behavior. First, a spatially coherent monochromatic laser beam passes through an SLM, which introduces an arbitrary EEG phase-only mask. The modified beam is collected by a CCD. Further, the intensity is multiply with the QW digitally...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Yuval Aharonovich, Mickey Scheinowitz, Sharon Zlochiver, Yuval Aharonovich, Mickey Scheinowitz, Sharon Zlochiver, Yuval Aharonovich, Sharon Zlochiver, Mickey Scheinowitz
Heart exposure to 16Hz magnetic fields (MFs) was shown to be cardio-protective for diseased hearts; still, the mechanism of this effect is unknown. We hypothesize that a possible one mechanism is an increased trans-membrane KATP channel open probability due to modulation of the degree of dissociation between K(+) ions, having a resonance frequency of 16Hz, and the channel selectivity filter. The Fan-Makielski Markovian KATP channel model was adopted, and the MF bio-effect was manifested by modulating the open probability of the channel using the predictive MF bio-effect parameter based on Binhi's quantum mechanics model...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Nagaiyan Sekar, Ramaiah D, Yogesh Gawale, Adarsh N, Joseph J, M Pramanik, S K Kalva
Four novel N-ethylcarbazole linked aza-BODIPY dyes (8a-b and 9a-b) were synthesized and characterized. The presence of N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, ca. 650-730 nm, of electromagnetic spectra. These dyes possess strong molar absorptivity in the range of 3-4 x 104 M-1cm-1 with low fluorescence quantum yields. The triplet excited state as well as singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core iodinated dyes 9a-b showed excellent triplet quantum yield of ca...
February 22, 2017: Chemistry: a European Journal
Marina Radulaski, Matthias Widmann, Matthias Niethammer, Jingyuan Linda Zhang, Sangyun Lee, Torsten Rendler, Konstantinos G Lagoudakis, Nguyen Tien Son, Erik Janzén, Takeshi Ohshima, Jörg Wrachtrup, Jelena Vuckovic
Silicon carbide is a promising platform for single photon sources, quantum bits (qubits) and nanoscale sensors based on individual color centers. Towards this goal, we develop a scalable array of nanopillars incorporating single silicon vacancy centers in 4H-SiC, readily available for efficient interfacing with free-space objective and lensed-fibers. A commercially obtained substrate is irradiated with 2 MeV electron beams to create vacancies. Subsequent lithographic process forms 800 nm tall nanopillars with 400-1,400 nm diameters...
February 22, 2017: Nano Letters
Chao-Xian Yan, Fan Yang, Xing Yang, Da-Gang Zhou, Pan-Pan Zhou
The Diels-Alder reaction between 3-vinylindoles and methyleneindolinone can proceed both with catalyst-free and bisthiourea catalyst, the reaction with bisthiourea is much faster and yields product with even higher stereoselectivity. The reaction mechanisms, origin of stereoselectivity and role of catalyst were elaborated based on quantum mechanical calculations and theoretical methods of reactivity indexes, NCI, QTAIM and distortion/interaction models. In uncatalyzed reaction, the two C-C bonds formed undergo the conversion from noncovalent to covalent bonding via concerted asynchronous mechanism...
February 22, 2017: Journal of Organic Chemistry
Hao Shen, Li Chen, Lorenzo Ferrari, Meng-Hsien Lin, N Asger Mortensen, Shangjr Gwo, Zhaowei Liu
The advances in recent nanofabrication techniques have facilitated explorations of metal structures into nanometer scales, where the traditional local-response Drude model with hard-wall boundary conditions fails to accurately describe their optical responses. The emerging nonlocal effects in single ultrasmall silver nanoparticles have been experimentally observed in single-particle spectroscopy enabled by the unprecedented high spatial resolution of electron energy loss spectroscopy (EELS). However, unambiguous optical observation of such new effects in gold nanoparticles has yet not been reported, due to the extremely weak scattering and the obscuring fingerprint of strong interband transitions...
February 22, 2017: Nano Letters
Jinglei Chen, Guanyong Wang, Yanan Tang, Hao Tian, Jinpeng Xu, Xianqi Dai, Hu Xu, Jinfeng Jia, Wingkin Ho, Maohai Xie
Monolayer (ML) transition-metal dichalcogenides exist in different phases, such as hexagonal (2H) and monoclinic (1T') structures. They show very different properties: semiconducting for 2H-MoTe2 and semi-metallic for 1T'-MoTe2. The formation energy difference between 2H and 1T' phase MoTe2 is small, so there is a high chance to tune the structures of MoTe2 and thereby to bring in applications of phase-change electronics. In this paper, we report growth of both 2H- and 1T'-MoTe2 ML by molecular-beam epitaxy (MBE) and demonstrate its tenability by changing the conditions of MBE...
February 22, 2017: ACS Nano
Christian Slawik, Christiane Rickmeyer, Martin Brehm, Alexander Böhme, Gerrit Schüürmann
Glutathione (GSH) has so far been considered to facilitate detoxification of soft organic electrophiles through covalent binding at its cysteine (Cys) thiol group, followed by stepwise catalyzed degradation and eventual elimination along the mercapturic acid pathway. Here we show that in contrast to expectation from HSAB theory, Michael-acceptor ketones, aldehydes and esters may form also single, double and triple adducts with GSH involving β-carbon attack at the much harder N-terminus of the γ-glutamyl (Glu) unit of GSH...
February 22, 2017: Environmental Science & Technology
Jean-Alexandre Richard, Michelle Jui Hsien Ong, Sylvain Debieu, Mathieu Moreau, Anthony Romieu
The effective synthesis of extended conjugated N,N-dialkylamino-nor-dihydroxanthene-based fluorophores is described from diversely functionalized salicylic aldehydes. The access to these original fluorescent derivatives proceeded in two steps through a one-pot construction of the unusual nor-dihydroxanthene (nor-DHX) scaffold followed by a diversification step providing a wide variety of nor-DHX-hemicyanine fused dyes emitting in the range 730-790 nm. The versatility of our approach has enabled a further extension to the late-stage introduction of negatively/positively charged polar groups onto their terminal nitrogen heterocyclic subunit giving access to the first water-soluble and/or bioconjugatable members of this emerging class of NIR fluorophores...
February 22, 2017: Chemistry, An Asian Journal
Igor Altfeder, Andrey A Voevodin, Michael H Check, Sarah M Eichfeld, Joshua A Robinson, Alexander V Balatsky
Using quantum tunneling of electrons into vibrating surface atoms, phonon oscillations can be observed on the atomic scale. Phonon interference patterns with unusually large signal amplitudes have been revealed by scanning tunneling microscopy in intercalated van der Waals heterostructures. Our results show that the effective radius of these phonon quasi-bound states, the real-space distribution of phonon standing wave amplitudes, the scattering phase shifts, and the nonlinear intermode coupling strongly depend on the presence of defect-induced scattering resonance...
February 22, 2017: Scientific Reports
Fangchao Lu, Ning Tang, Liangliang Shang, Hongming Guan, Fujun Xu, Weikun Ge, Bo Shen
Magnetic transport spectroscopy is investigated in quantum point contacts (QPCs) fabricated in Al0.25Ga0.75N/GaN heterostructures. The magnetic field perpendicular to the two-dimensional electron gas (2DEG) is shown to depopulate the quasi-one-dimensional energy levels in the first two-dimensional (2D) subband faster than those in the second one. In GaN based heterostructures, the energy levels in the second 2D subband is generally concealed in the fast course of depletion and hence rarely detected. The perpendicular magnetic field facilitates the observation of the second 2D subband, and provides a method to study the properties of these energy levels...
February 22, 2017: Scientific Reports
László Deák, László Bottyán, Tamás Fülöp, Dániel Géza Merkel, Dénes Lajos Nagy, Szilárd Sajti, Kai Sven Schulze, Hartmut Spiering, Ingo Uschmann, Hans-Christian Wille
Reciprocity is when wave or quantum scattering satisfies a symmetry property, connecting a scattering process with the reversed one. While reciprocity involves the interchange of source and detector, it is fundamentally different from rotational invariance, and is a generalization of time reversal invariance, occurring in absorptive media as well. Due to its presence at diverse areas of physics, it admits a wide variety of applications. For polarization dependent scatterings, reciprocity is often violated, but violation in the phase of the scattering amplitude is much harder to experimentally observe than violation in magnitude...
February 22, 2017: Scientific Reports
Wojciech Kozlowski, Santiago F Caballero-Benitez, Igor B Mekhov
A many-body atomic system coupled to quantized light is subject to weak measurement. Instead of coupling light to the on-site density, we consider the quantum backaction due to the measurement of matter-phase-related variables such as global phase coherence. We show how this unconventional approach opens up new opportunities to affect system evolution. We demonstrate how this can lead to a new class of final states different from those possible with dissipative state preparation or conventional projective measurements...
February 22, 2017: Scientific Reports
Marta P Estarellas, Irene D'Amico, Timothy P Spiller
We consider spin chain families inspired by the Su, Schrieffer and Hegger (SSH) model. We demonstrate explicitly the topologically induced spatial localisation of quantum states in our systems. We present detailed investigations of the effects of random noise, showing that these topologically protected states are very robust against this type of perturbation. Systems with such topological robustness are clearly good candidates for quantum information tasks and we discuss some potential applications. Thus, we present interesting spin chain models which show promising applications for quantum devices...
February 22, 2017: Scientific Reports
Joel D Cox, Andrea Marini, F Javier García de Abajo
High-harmonic generation in condensed-matter systems is both a source of fundamental insight into quantum electron motion and a promising candidate to realize compact ultraviolet and ultrafast light sources. While graphene is anticipated to efficiently generate high-order harmonics due to its anharmonic charge-carrier dispersion, experiments performed on extended samples using THz illumination have revealed only a weak effect. The situation is further complicated by the enormous electromagnetic field intensities required by this highly nonperturbative nonlinear optical phenomenon...
February 22, 2017: Nature Communications
S Poran, T Nguyen-Duc, A Auerbach, N Dupuis, A Frydman, Olivier Bourgeois
The superconductor-insulator transition (SIT) is considered an excellent example of a quantum phase transition that is driven by quantum fluctuations at zero temperature. The quantum critical point is characterized by a diverging correlation length and a vanishing energy scale. Low-energy fluctuations near quantum criticality may be experimentally detected by specific heat, cp, measurements. Here we use a unique highly sensitive experiment to measure cp of two-dimensional granular Pb films through the SIT. The specific heat shows the usual jump at the mean field superconducting transition temperature marking the onset of Cooper pairs formation...
February 22, 2017: Nature Communications
Christos Kokkinos, Anastasios Economou
Over the last years, nanomaterials have found many applications in the development of electrochemical biosensors. Among other functions, metal nanoparticles (NPs) and quantum dots (QDs) (semiconducting nanocrystals composed of metal salts) are increasingly being used as voltammetric labels in affinity biosensing. Labeling is based on the attachment of the label(s) on the target biomolecules or on a biorecognition reporting probe. After an appropriate specific affinity interaction between the target and the reporting probe, the metallic nanolabels are converted to the respective cations which are quantified by a voltammetric technique...
April 8, 2017: Analytica Chimica Acta
Bing Qu, Lei Yao, Hua-Ling Ma, Hong-Lei Chen, Zhi Zhang, Jiang Xie
Gastric adenocarcinoma (GC) is one of the most common malignancies in the world and one of the most frequent causes of cancer-related death. Autophagy is a highly regulated catabolic pathway responsible for the degradation of long-lived proteins and damaged intracellular organelles. However, the mechanism and guiding significance of autophagy in the development and progression of GC have remained to be elucidated. This study aimed to explore the clinicopathological significances and prognostic values of autophagy-related proteins AMBRA1 and Beclin-1 in GC...
February 2017: Journal of Huazhong University of Science and Technology. Medical Sciences
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