1,982 research outputs found
Realizing a Superconducting Square-Lattice Bismuth Monolayer
Interplay of crystal symmetry, strong spinorbit coupling (SOC), and
many-body interactions in low dimensional materials provides a fertile ground
for the discovery of unconventional electronic and magnetic properties and
versatile functionalities. Two-dimensional (2D) allotropes of group 15 elements
are appealing due to their structures and controllability over symmetries and
topology under strong SOC. Here, we report the heteroepitaxial growth of a
proximity-induced superconducting 2D square-lattice bismuth monolayer on
superconducting Pb films. The square lattice of monolayer bismuth films in a
symmetry together with a stripey moir\'e structure is clearly resolved by
our scanning tunneling microscopy and its atomic structure is revealed by
density functional theory (DFT) calculations. A Rashba-type spin-split Dirac
band is predicted by DFT calculations to exist at the Fermi level and becomes
superconducting through the proximity effect from the Pb substrate. We suggest
the possibility of a topological superconducting state in this system with
magnetic dopants/field. This work introduces an intriguing material platform
with 2D Dirac bands, strong SOC, topological superconductivity, and the moir\'e
superstructure.Comment: 21 pages, 4 figure
Infrared-Mediated Drug Elution Activity of Gold Nanorod-Grafted TiO 2
The purpose of this research was to prepare gold nanorod- (GNR-) grafted TiO2 nanotubes by thiolactic acid treatment and evaluate remote-controlled drug elution and antibacterial activity by infrared (IR) light irradiation. Tetracycline used as an antibiotic was loaded into GNR-grafted TiO2 nanotubes by using 2 w/v% polylactic acid solutions. A near-IR laser (830 nm) was used for remote-controlled IR light irradiation. Results of SEM, TEM, XRD, and EDX revealed that GNR chemically bonded to the whole surface of the TiO2 nanotubes. An antibiotic release test revealed that on-off drug elution was triggered effectively by the photothermal effect of GNR grafted on TiO2 nanotubes. Furthermore, an antibacterial agar zone test indicated that the annihilated zone of Streptococcus mutans in the experimental group with IR light irradiation was significantly larger than that of the corresponding group without IR light irradiation (P<0.05). Therefore, GNR-grafted TiO2 nanotubes would be expected to extend the limited usage of TiO2, which show photocatalytic activity only within the ultraviolet (UV) to IR region, thereby allowing the development of novel fusion technologies in the field of implant materials
Technological Progress in Generation of Induced Pluripotent Stem Cells for Clinical Applications
Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) is achieved by viral-mediated transduction of defined transcription factors. Generation of iPSCs is of great medical interest as they have the potential to be a source of patient-specific cells. For the eventual goal of clinical application, it is necessary to overcome the limitations of low reprogramming efficiency and chromosomal abnormalities due to viral DNA integration. In this paper, we summarize the current state of reprogramming technology for generation of iPSCs and also discuss potential approaches to the development of safe iPSCs for personalized cell-based replacement therapy
Real-time response estimation of structural vibration with inverse force identification
This study aimed to develop a virtual sensing algorithm of structural
vibration for the real-time identification of unmeasured information. First,
certain local point vibration responses (such as displacement and acceleration)
are measured using physical sensors, and the data sets are extended using a
numerical model to cover the unmeasured quantities through the entire spatial
domain in the real-time computation process. A modified time integrator is then
proposed to synchronize the physical sensors and the numerical model using
inverse dynamics. In particular, an efficient inverse force identification
method is derived using implicit time integration. The second-order ordinary
differential formulation and its projection-based reduced-order modeling is
used to avoid two times larger degrees of freedom within the state space form.
Then, the Tikhonov regularization noise-filtering algorithm is employed instead
of Kalman filtering. The performance of the proposed method is investigated on
both numerical and experimental testbeds under sinusoidal and random excitation
loading conditions. In the experimental test, the algorithm is implemented on a
single-board computer, including inverse force identification and unmeasured
response prediction. The results show that the virtual sensing algorithm can
accurately identify unmeasured information, forces, and displacements
throughout the vibration model in real time in a very limited computing
environment.Comment: 24 Pages, 15 Figures, 10 Table
Cognitive improvement after long-term electrical stimulation of bilateral anterior thalamic nucleus in refractory epilepsy patients
AbstractIntroductionThe cognitive and behavioral effect of deep brain stimulation (DBS) administered to the deep cerebral nuclei for epilepsy treatment is unknown. We investigated the cognitive outcomes at least 12 months after DBS to the bilateral anterior thalamic nucleus (ATN) for controlling intractable epilepsy.MethodsNine patients with intractable epilepsy who were not candidates for resective surgery, but who were treated by bilateral ATN DBS underwent cognitive and behavioral assessments before implantation and more than 1 year after DBS surgery. Postoperative cognitive assessments were carried out under a continuous stimulation mode.ResultsThe mean seizure-reduction rate of these patients after ATN DBS was 57.9% (35.6–90.4%). Cognitive testing showed favorable results for verbal fluency tasks (letter and category, p<0.05), and a significant improvement in delayed verbal memory was observed (p=0.017). However, we did not observe any significant changes in general abilities (IQ, MMSE), information processing (digit forward and backward, Trail A, and Digit Symbol), or executive function (Trail B and WCST). Interestingly, we did not observe any significant cognitive decline approximately 1 year (mean, 15.9 months) after ATN DBS surgery.ConclusionsWe showed that ATN DBS not only resulted in promising clinical effects but was also associated with improvements in both verbal recall and oral information processing, which may be related to the bilateral activation of the fronto-limbic circuit following DBS surgery. Further controlled, long-term studies with larger populations are warranted for elucidating the clinical effects of ATN DBS
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