Strong Two-Mode Parametric Interaction and Amplification in a Nanomechanical Resonator

We demonstrate a scheme for amplifying nanomechanical motion based on strong parametric interactions between two independent flexural modes of a single nanobeam. A static electric field polarizes a dielectric nanobeam and additional radio-frequency voltage excites the motion of the beam. When the excitation frequency equals the difference of the two resonance frequencies, we observe a mode- splitting feature in the strong-coupling regime. If the excitation frequency overlaps the sum of the two resonance frequencies, the optical signal from the thermal motion of the nanomechanical resonator is amplified by more than 30 dB. We demonstrate that coupling between the odd- and even-numbered oscillatory mode can be realized and a coupled-mode theory is developed from a simple capacitor model to explain our observations. We conclude that the results are thoroughly explained by parametric interactions between two independent nanomechanical modes in thermal motion. This observation of parametric control can be employed in nanomechanical force detection and molecular sensing applications. © 2018 American Physical Societ

Van Der Waals Epitaxial Growth of Superconductive NbS2

Metallic NbS2 is one of the layered transition metal dichalcogenides (TMDCs) that exhibits intrinsic physical phenomena at low temperature limits such as superconductivity and charge density waves (CDW), although it has not been studied as extensively as other compounds. The unique properties of NbS2 were sufficiently confirmed in mechanically exfoliated NbS2. Chemical synthesis of NbS2 with atomically thickness is of great importance to property investigation and device applications. However, it is of great challenge to synthesize NbS2 with uniform layer. Unlike chemical vapor deposition (CVD) which loads the sources into a process chamber with a substrate, metalorganic chemical vapor deposition (MOCVD) can regulate the flow of the sources and control the material growth by supplying the sources in separate canisters. Several TMDCs such as MoS2 and WS2 can be grown well by MOCVD, and various studies using these materials have already been conducted. However, MOCVD for NbS2 has been rarely reported due to still lacking suitable MO precursors. In this study, heteroepitaxial growth of single crystalline NbS2 monolayer over a large area of graphene is achieved uniformly by MOCVD. By transmission electron microscope studies, it is verified that single crystalline NbS2 monolayer has high crystallinity and epitaxial relationship with graphene. We also try scanning tunneling microscope (STM) on single crystalline NbS2/graphene heterostructures for studying about its intrinsic superconductivity. In order to protect the unique properties of NbS2 from oxidation, synthesized NbS2 was unloaded after in-situ passivation with S film that was thermally removed in the analysis chamber. Our synthetic process provides a new way towards uniform synthesis of NbS2 nanosheets and could be widely applied to further study.1

C-phycocyanin from <i>Limnothrix</i> Species KNUA002 Alleviates Cisplatin-Induced Ototoxicity by Blocking the Mitochondrial Apoptotic Pathway in Auditory Cells

Ototoxicity, or adverse pharmacological effects on the inner ear or auditory nerve, is a common side effect of cisplatin, a platinum-based drug widely used in anticancer chemotherapy. Although the incidence of ototoxicity is high among patients that receive cisplatin therapy, there is currently no effective treatment for it. The generation of excessive reactive oxygen species (ROS) is considered to be the major cause of cisplatin-induced ototoxicity. C-phycocyanin (C-PC), a blue phycobiliprotein found in cyanobacteria and red algae, has antioxidant and anticancer activities in different experimental models in vitro and in vivo. Thus, we tested the ability of C-PC from Limnothrix sp. KNUA002 to protect auditory cells from cisplatin-induced ototoxicity in vitro. Pretreatment with C-PC from Limnothrix sp. KNUA002 inhibited apoptosis and protected mitochondrial function by preventing ROS accumulation in cisplatin-treated House Ear Institute-Organ of Corti 1 (HEI-OC1) cells, a mouse auditory cell line. Cisplatin increased the expression of Bax and reduced the expression of Bcl-2, which activate and inhibit, respectively, the mitochondrial apoptotic pathway in response to oxidative stress. Pretreatment with C-PC prior to cisplatin treatment caused the Bax and Bcl-2 levels to stay close to the levels in untreated control cells. Our results suggest that C-PC from Limnothrix sp. KNUA002 protects cells against cisplatin-induced cytotoxicity by inhibiting the mitochondrial apoptotic pathway

Quantitative radiological analysis and clinical outcomes of urgent EC-IC bypass for hemodynamic compromised patients with acute ischemic stroke

This study aimed to demonstrate the effectiveness of urgent extracranial-to-intracranial bypass (EIB) in acute ischemic stroke (AIS) through quantitative analysis of computed tomography perfusion (CTP) results using RAPID software. We retrospectively analyzed 41 patients who underwent urgent EIB for AIS under strict operation criteria. The quantitative data from CTP images were reconstructed to analyze changes in pre- and postoperative perfusion status in terms of objective numerical values using RAPID software. Short- and long-term clinical outcomes, including complications and neurological status, were also analyzed. Postoperatively, the volume of time-to-max (Tmax) &gt; 6 s decreased significantly; it continued to improve significantly until 6 months postoperatively (preoperative, 78 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 7 ml; p = 0.000). Ischemic core-penumbra mismatch volumes were also significantly improved until 6 months postoperatively (preoperative, 72 ml (median); immediate postoperative, 23 ml; postoperative 6 months, 5 ml; p = 0.000). In addition, the patients&apos; neurological condition improved significantly (p &lt; 0.001). Only one patient (2.3%) showed progression of infarction. Urgent EIB using strict indications can be a feasible treatment for IAT-ineligible patients with AIS due to large vessel occlusion or stenosis.N

Local recurrence and subsequent endoscopic treatment after endoscopic piecemeal mucosal resection with or without precutting in the colorectum

Background/Aims: Precutting before endoscopic piecemeal mucosal resection (EPMR) may increase colorectal polyp resection effectiveness. We aimed to identify risk factors for recurrence after conventional EPMR (CEPMR) and precut EPMR (PEPMR) and investigated endoscopic treatment outcomes for recurrent cases.Methods: The medical records of patients with colorectal polyps treated by EPMR were analyzed. Patients without follow-up surveillance colonoscopies were excluded.Results: Among 359 lesions, the local recurrence rate on the first surveillance colonoscopy was 5.8% (18/312) and 6.4% (3/47) after CEPMR and PEPMR, respectively. Among lesions without recurrence at the first surveillance colonoscopy, the rates of late recurrence on subsequent surveillance colonoscopy were 3.9% (6/152) and 0% after CEPMR and PEPMR, respectively. Larger tumor size was the only independent risk factor for recurrence (odds ratio, 7.93; 95% confidence interval, 1.95–32.30; P<0.001). Endoscopic treatment was performed for all 27 recurrences. A combination of ≥2 endoscopic treatment modalities was used in 19 of 27 recurrences (70.4%). Surveillance colonoscopies were performed in 20 of 27 recurrences after endoscopic treatment. One (5.0%) had a re-recurrence and was treated by surgical resection because recurrence occurred at the appendiceal orifice. Nineteen of 20 lesions (95.0%) could be cured endoscopically, although 3 of the 19 showed second or third recurrences and were treated by repeat endoscopic resection.Conclusions: The local recurrence rates after CEPMR and PEPMR were similar. Larger tumor size was an independent risk factor for local recurrence after EPMR. Endoscopic treatment of recurrences resulted in high cure rates, although combination methods were necessary in many cases

Ultra-stable and tough bioinspired crack-based tactile sensor for small legged robots

Abstract For legged robots, collecting tactile information is essential for stable posture and efficient gait. However, mounting sensors on small robots weighing less than 1 kg remain challenges in terms of the sensor’s durability, flexibility, sensitivity, and size. Crack-based sensors featuring ultra-sensitivity, small-size, and flexibility could be a promising candidate, but performance degradation due to crack growing by repeated use is a stumbling block. This paper presents an ultra-stable and tough bio-inspired crack-based sensor by controlling the crack depth using silver nanowire (Ag NW) mesh as a crack stop layer. The Ag NW mesh inspired by skin collagen structure effectively mitigated crack propagation. The sensor was very thin, lightweight, sensitive, and ultra-durable that maintains its sensitivity during 200,000 cycles of 0.5% strain. We demonstrate sensor’s feasibility by implementing the tactile sensation to bio-inspired robots, and propose statistical and deep learning-based analysis methods which successfully distinguished terrain type

Elevated C-reactive protein level during clinical remission can predict poor outcomes in patients with Crohn's disease.

Intestinal inflammation and mucosal damage in Crohn's disease (CD) are believed to progress even during clinical remission. We investigated the long-term prognosis of CD patients in clinical remission according to serum C-reactive protein (CRP) levels. This study included 339 CD patients in clinical remission (Crohn's disease activity index < 150) for more than 6 months between January 2008 and December 2010. Clinical outcomes were compared between patients with normal and elevated CRP levels during clinical remission. During clinical remission, 150 patients had normal CRP consistently and 189 had elevated CRP at least once. During follow-up (median, 7.9 years [interquartile range, 6.8-8.0]), the Kaplan-Meier analysis with the log-rank test showed that normal CRP group had a longer CD-related hospitalization-free survival (P = 0.007) and a longer CD-related intestinal resection-free survival (P = 0.046) than elevated CRP group. In multivariate analysis, elevated CRP was significantly and independently associated with an increased risk of subsequent CD-related hospitalization (adjusted hazard ratio [aHR] 1.787, 95% confidence interval [CI]: 1.245-2.565, P = 0.002) and of subsequent CD-related intestinal resection (aHR 1.726, 95% CI: 1.003-2.969, P = 0.049). The most common reason for CD-related hospitalization was penetrating complications (35.6%). Even when CD patients are in clinical remission, elevated CRP is significantly associated with subsequent CD-related hospitalization and CD-related intestinal resection during follow-up. CD patients in clinical remission but elevated CRP should receive more careful attention and timely interventions to improve long-term outcomes