47 research outputs found

    Hyperfine interaction induced decoherence and deterministic teleportation of electrons in a quantum dot nanostructure

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    Recently, de Visser and Blaauboer [Phys. Rev. Lett. {\bf 96}, 246801 (2006)] proposed the most efficient deterministic teleportation protocol T\cal T for electron spins in a semiconductor nanostructure consisting of a single and a double quantum dot. However, it is as yet unknown if T\cal T can be completed before decoherence sets in. In this paper we analyze the detrimental effect of nuclear spin baths, the main source of decoherence, on T\cal T. We show that nonclassical teleportation fidelity can be achieved with T\cal T provided certain conditions are met. Our study indicates that realization of quantum computation with quantum dots is indeed promising.Comment: 10 page

    Effects of contusion load on cervical spinal cord:A finite element study

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    Injury of cervical spine is a common injury of locomotor system usually accompanied by spinal cord injury, however the injury mechanism of contusion load to the spinal cord is not clear. This study aims to investigate its injury mechanism associated with the contusion load, with different extents of spinal cord compression. A finite element model of cervical spinal cord was established and two scenarios of contusion injury loading conditions, i.e. back-to-front and front-to-back loads, were adopted. Four different compression displacements were applied to the middle section of the cervical spinal cord. The distributions of von Mises stress in middle transverse cross section were obtained from the finite element analysis. For the back-to-front loading scenario, the stress concentration was found in the area at and near the central canal and the damage may lead to the central canal syndrome from biomechanical point of view. With the front-to-back load, the maximum von Mises stress located in central canal area of gray matter when subject to 10% compression, whilst it appeared at the anterior horn when the compression increased. For the white matter, the maximum von Mises stress appeared in the area of the anterior funiculus. This leads to complicated symptoms given rise by damage to multiple locations in the cervical spinal cord. The illustrative results demonstrated the need of considering different loading scenarios in understanding the damage mechanisms of the cervical spinal cord, particularly when the loading conditions were given rise by different pathophysiological causes

    Dual functionalized hyaluronic acid micelles loading paclitaxel for the therapy of breast cancer

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    Although many carriers for the delivery of chemotherapeutic drugs have been investigated, the disadvantages of passive targeting and uncontrolled drug release limit their utility. Herein, hyaluronic acid (HA) was hydrophobically modified to serve as a carrier for binding to cluster determinant 44 (CD44) overexpressed on tumor cell surfaces. Specifically, after deacetylation, HA was grafted to dodecylamine or tetradecylamine to afford amphiphilic zwitterionic polymer micelles, designated dHAD and dHAT, respectively, for the delivery of paclitaxel (PTX). The micelles were negatively charged at pH 7.4 and positively charged at pH 5.6, and this pH sensitivity facilitated PTX release under acidic conditions. The cell uptake efficiencies of the dHAD-PTX and dHAT-PTX micelles by MCF-7 cells after 4 h of incubation were 96.9% and 95.4%, respectively, and their affinities for CD44 were twice that of HA. Furthermore, the micelles markedly inhibited tumor growth both in vitro and in vivo, with IC50 values of 1.943 μg/mL for dHAD-PTX and 1.874 μg/mL for dHAT-PTX for MCF-7 cells; the tumor inhibition rate of dHAD-PTX (92.96%) was higher than that of dHAT-PTX (78.65%). Importantly, dHAD and dHAT micelles showed negligible systemic toxicity. Our findings suggest that these micelles are promising delivery vehicles for antitumor drugs

    Spousal concordance in adverse childhood experiences and the association with depressive symptoms in middle-aged and older adults: findings across China, the US, and Europe

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    BackgroundAdverse childhood experiences (ACEs) are associated with higher depressive risks in adulthood. Whether respondents’ ACEs are associated with their own depressive symptoms in adulthood and whether this association extends to their spouses’ depressive symptoms remain unexplored.MethodsData were from China Health and Retirement Longitudinal Study (CHARLS), the Health and Retirement Study (HRS), and the Survey of Health, Ageing and Retirement in Europe (SHARE). ACEs were categorized into overall, intra-familial, and extra-familial ACEs. Correlations of couples’ ACEs were calculated using Cramer’s V and partial Spearman’s correlation. Associations of respondents’ ACEs with spousal depressive symptoms were assessed using logistic regression, and mediation analyses were conducted to explore the mediating role of respondents’ depressive symptoms.ResultsSignificant associations between husbands’ ACEs and wives’ depressive symptoms, with odds ratios (ORs) and 95% confidence intervals (CIs) of 2.09 (1.36–3.22) for 4 or more ACEs in CHARLS, and 1.25 (1.06–1.48) and 1.38 (1.06–1.79) for 2 or more ACEs in HRS and SHARE. However, wives’ ACEs were associated with husbands’ depressive symptoms only in CHARLS and SHARE. Findings in intra-familial and extra-familial ACEs were consistent with our main results. Additionally, respondents’ depressive symptoms mediated more than 20% of the effect of respondents’ ACEs on spousal depressive symptoms.ConclusionWe found that ACEs were significantly correlated between couples. Respondents’ ACEs were associated with spousal depressive symptoms, with respondents’ depressive symptoms mediating the association. The bidirectional implications of ACEs on depressive symptoms should be considered within household and effective interventions are warranted

    Converging lasing from floating GaN Penrose microcavity

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    A floating GaN Penrose microcavity is fabricated by standard micro-and-nano fabrication techniques. Ultraviolet whispering gallery mode and Fabry-Pérot (F-P) mode lasings are obtained under optical pumping conditions at room temperature. The lasing characteristics of the emission intensity, the threshold and the resonance mechanism are presented. It should be noted that the Fabry-Pérot mode lasing could be converged due to the focusing effect of half-ellipse shape mirrors. Analysis of the lasing mode number is also given to confirm the lasing resonance mechanism. A commercial two-dimensional finite difference time domain simulation software is used to study near-field distribution and far-field distribution of a Penrose microcavity, presenting the resonance mechanism of two types of lasing modes. It is significant for improving devices' coupling efficiency, as well as the high-density integrated optoelectronics system

    Dual-band light-emitting diode based on microwheel cavity

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    Compact and broadband electroluminescent (EL) devices have garnered considerable interest in recent years. In this study, we have fabricated a light-emitting diode (LED) based on a GaN microwheel cavity with a peak emission wavelength of 438 nm. Another emission peak at 512 nm is realized by coating CH3NH3PbBr3 on the LED. The microwheel-cavity–based LED is fabricated by photolithography and inductively coupled plasma etching process. The opto-electrical performance of the device is characterized in terms of the EL spectrum, luminescence intensity, full width at half maximum, and 3 dB bandwidth. Compared to the device without the CH3NH3PbBr3 layer, the proposed device exhibits dual-band illumination and higher 3 dB bandwidth with potential applications in optical communication

    Wet Oxidation of Pharmaceutical Sludge for the Treatment and Production of Value-Added Materials

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    The wet oxidation of pharmaceutical sludge for the treatment and production of value-added materials was investigated. The experiments were carried out in a stainless-steel autoclave reactor with chemical synthetic pharmaceutical sludge. The highest removal rate of total suspended solids (90.1%) and volatile suspended solids (98.4%) was achieved at 260 °C for 60 min with an initial oxygen pressure of 0.8 MPa. Simultaneously, the total chemical oxygen demand removal rate (78.7%) and the soluble chemical oxygen demand removal rate (81.6%) were obtained. The volatile fatty acid concentration—including acetic acid, propanoic acid, isobutyric acid and isovaleric acid—increased to 4819 mg/L with pH 12.56, which indicated the possibility of improving the quality of wet oxidized sludge solution as a potential carbon source by adding reagents. Scanning electron microscopy images showed that the sludge became a loose porous structure after wet oxidation, which is beneficial for dewatering performance. Energy dispersive spectroscopy images illustrate that carbon elements in sludge migrate from solid to liquid phases during the wet oxidation process. These results provide meaningful data for the design of further works and demonstrate that wet oxidation is a promising method for the treatment of pharmaceutical sludge, and the produced volatile fatty acids, including acetic acid and propanoic acid, are potential carbon sources for the biological treatment of wastewater

    Morphological Characteristics of Postembryonic Early Development of the Thamnaconus septentrionalis

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    The morphological characteristics, ecological habits, and physiological structures of fish vary rapidly in the early growth and development stage. Understanding the changes in the postembryonic early development morphology of organs or tissues could provide basic information for the classification or identification of fish and the investigation or utilization of early resources. Morphological characteristic observation is one of the most commonly used methods. The existing studies on the early development of a certain trait in the late larval and juvenile stage are unclear. Most of the digital images are side views, resulting in a lack of dorsal views, ventral views, or local images, which is not conducive to the understanding of larval and juvenile. In this study, the variations in observable, measurable, and countable traits in postembryonic early development of Thamnaconus septentrionalis were explored using optical microscopy and stereomicroscopy. The observable traits included the developmental changes of yolk sac, scales, and notochord curvature. The measurable traits included the growth changes of total length, body length, body height, and oral fissure. The countable characters included the number of fins in the second dorsal fin, anal fin, caudal fin, and the number of pterygiophore. The results showed that at (23.0±1.0) ℃, the newly hatched larvae moved up and down in the water, with a phenomenon of convergent clustering under light irradiation; the pectoral fin appeared at 1 d, and the heart rate was approximately 50 beats/min; the optic capsule was completely black, the maxillar appeared, the oral fissure extended below the eyes, the yolk sac disappeared, and the first dorsal fin base appeared at 4 d; the girdle was single and colorless and began from the front edge of the belly, the oil globule disappeared, and the pelvic fin base appeared at 7 d; the first dorsal fin base and pelvic fin base broke membrane at 8 d; the first dorsal fin and pelvic fin were significantly longer than before, transparent rounded scales were observed at 9 d; swimming ability was improved, indicated by hovering back and forth gnawing pool wall, transversally conical barbs appeared at the base of the first dorsal fin at 11 d; the swim bladder and postcleithrum on both sides of the belly were clearly visible at 12 d; the second dorsal fin and anal fin pterygiophore appeared at 14 d, the second dorsal fin pterygiophore spans seven sarcomeres and the anal fin pterygiophore spans six sarcomeres. There are 10~12 melanin masses in the second dorsal fin and 5~6 in the anal fin, the conical teeth appeared on the upper and lower jaws at 16 d; the second dorsal fin and anal fin were differentiated at 19 d; the swim bladder fills about 25% of the abdominal cavity; notochord curves upward clearly and the stalk of caudal fin came out at 20 d; the fin strips of the second dorsal fin, anal fin, and caudal fin were well-developed at 24 d; the open mouth was round and changed from swallowing to sucking at 30 d, and the rainbow cells were colorful and the body surface near the gill was the most dense; the abdominal cavity has a strong metallic texture, the hard spine of the pelvic fin was degraded, close to the girdle at 39 d; 4~5 black bands were arranged regularly on the body, and the lateral line was consistent with the vertebral column at 50 d. The R2 values of the curve equations of measurable traits were all greater than 0.90. The height of the first dorsal fin increased exponentially 4~30 d. The visual sac increased linearly from 0~11 d to 11~20 d, and the increment of 0~11 d was less than that of 11~20 d, while the increment of 21~30 d was exponential. The oral fissure in 4~13 d and 22~30 d increased linearly, while that in 13~22 d decreased linearly. The total length, body length, and body height increased linearly before the inflection point and exponentially after the inflection point, which was concentrated in 19~23 d. The number of fin pterygiophore of the second dorsal fin was 31~36, while that in the anal fin was 33~35. The number of pectoral fins and caudal fins were 15~18 and 12, respectively. In conclusion, metamorphosis occurs in the postembryonic early development of T. septentrionalis, showing an allometric growth pattern, with a slow linear growth in the rotifer-feeding stage and a fast exponential growth in the artemia-feeding stage. The changes in the first dorsal fin and pelvic fin were correlated with age in days. The changes in the second dorsal and anal fins were correlated with the total length. This study enriches the early biological theory of T. septentrionalis and provides basic data for the investigation or utilization of its seedling breeding and resources. The partial enlarged detail is helpful for scholars to further understand the larval or juvenile fish and perform deep research
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