Drug delivery by a self-assembled DNA tetrahedron for overcoming drug resistance in breast cancer cells

A DNA tetrahedron is employed for efficient delivery of doxorubicin into drug-resistant breast cancer cells. The drug delivered with the DNA nanoconstruct is considerably cytotoxic, whereas free doxorubicin is virtually non-cytotoxic for the drug-resistant cells. Thus, the DNA tetrahedron, made of the inherently natural and biocompatible material, can be a good candidate for the drug carrier to overcome MDR in cancer cells.close11

Examining Disproportionality in Adult Protective Services Decisions in Southern California

Adult protective services (APS) are the primary form of state intervention in cases of elder mistreatment in the United States. Accurate and unbiased identification of elder abuse and neglect is crucial to protect elders from mistreatment and also to reduce overpolicing of vulnerable groups. This study uses APS report microdata (N=14,448) from a county APS agency in Southern California to identify racial disproportionality in the rate of confirmed elder abuse. Our analysis finds that APS investigators are significantly less likely to confirm reported cases of elder mistreatment for Latinx victims than for white victims. While we found no significant relationship between APS case confirmation and API identity overall, disaggregation of the API identity group reveals a bimodal effect. East Asian APS victims are significantly more likely to be confirmed for elder abuse than whites, while Southeast Asians are significantly less likely to be confirmed. English proficiency also moderates APS confirmation rate for Southeast Asians, with non-English-speaking Southeast Asians being significantly more likely to be confirmed for elder abuse. Contrary to expectations, Black racialized identity did not have a statistically significant relationship with APS case confirmation as compared to whites. Study findings illustrate the need for improved outreach and reporting practices around elder mistreatment and the importance of examining inter-ethnic differences within the API monolith when designing policy interventions for older adults

Manipulation of oxygen atoms on epitaxial graphene by a variable-temperature scanning tunneling microscope

Graphene, consisting of atomically thin honeycomb lattice of sp2-bonded carbon atoms, is one of the most popular 2D materials. To modify electronic properties of graphene, one can chemically functionalize graphene with hydrogen [1,2], fluorine [3], and oxygen [4]. Chemically homogeneous oxidation of epitaxial graphene was realized by depositing atomic oxygen in ultrahigh vacuum (UHV), suggesting a new possibility of nanopatterning on graphene oxide [5]. In this talk, we would like to show electronic properties and atomic structures of oxidized epitaxial graphene, which we measured using scanning tunneling microscopy (STM). To prepare oxidized epitaxial graphene, we generated atomic oxygen beams by passing oxygen molecules through a hot Ir capillary. Then we deposited atomic oxygen beams on the epitaxial graphene substrate. Once the atomic oxygen was identified, we brought a STM tip on it and applied a voltage pulse to manipulate it. This manipulation of oxygen atoms on epitaxial graphene allows us to tailor local electronic properties of graphene in atomic scale. Furthermore, to minimize thermal drift in temperature-dependent STM measurements, we constructed a variable-temperature STM with a small piezoelectric motor called KoalaDrive [6], which has been working well at low temperature. [1] D. C. Elias, R. R. Nair, T. M. G. Mohiuddin, S. V. Morozov, P. Blake, M. P. Halsall, A. C. Ferrari, D. W. Boukhvalov, M. I. Katsnelson, A. K. Geim, and K. S. Novoselov, Science 323, 610 (2009). [2] R. Balog, B. Jørgensen, L. Nilsson, M. Andersen, E. Rienks, M. Bianchi, M. Fanetti, E. Lægsgaard, A. Baraldi, S. Lizzit, Z. Sljivancanin, F. Besenbacher, B. Hammer, T. G. Pedersen, P. Hofmann, and L. Hornekær, Nat. Mater. 9, 315 (2010). [3] F. Karlický, K. Kumara Ramanatha Datta, M. Otyepka, and R. Zbořil, ACS Nano 7, 6434 (2013). [4] D. R. Dreyer, S. Park, C. W. Bielawski, and R. S. Ruoff, Chem. Soc. Rev. 39, 228 (2010). [5] M. Z. Hossain, J. E. Johns, K. H. Bevan, H. J. Karmel, Y. T. Liang, S. Yoshimoto, K. Mukai, T. Koitaya, J. Yoshinobu, M. Kawai, A. M. Lear, L. L. Kesmodel, S. L. Tait, and M. C. Hersam, Nat. Chem. 4, 305 (2012). [6] V. Cherepanov, P. Coenen, and B. Voigtländer, Rev. Sci. Instrum. 83, 23703 (2012).2

Reliable Flying IoT Networks for UAV Disaster Rescue Operations

Recently, UAVs (unmanned air vehicles) have been developed with high performance, and hence, the range of system utilizing UAVs has also been widening. UAVs are even considered as connected mobile sensors and are claimed to be the future of IoT (Internet of Things). UAVs’ mission fulfillment is relying on the efficiency and performance of communication in a FANET (Flying Ad hoc NETwork) environment where UAVs communicate with each other through an ad hoc network without infrastructure. Especially, for mission-critical applications such as disaster rescue operations, reliable and on-time transmission of rescue information is very critical. To develop the reliable FANETs, a realistic network simulation platform for UAV communication has become an important role. Motivated by this observation, this paper first presents a study on realistic FANET environment simulation platform. On top of the proposed platform, we also design a stable UAV communication protocol with high packet delivery and bounded end-to-end communication delay

Systematic investigation of wear-induced cold welding in ultrahigh vacuum piezoelectric motors with non-metallic coatings

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ATOMIC MANIPULATION OF ATOMIC OXYGEN ON GRAPHENE

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Layer-by-Layer Assembly for Graphene-Based Multilayer Nanocomposites: The Field Manual

With its superior electrical, optical, thermal, and mechanical properties, graphene offers a versatile platform for fabricating innovative hybrid composite materials with diverse potential applications. The preparation of graphene-based composites, particularly as thin films with nanoscale precision, is highly important for fabricating electrodes for energy and electronic devices as well as for facilitating understanding of the interplay between each component within the composites. In this context, the layer-by-layer (LbL) assembly technique offers a simple and versatile process for the fabrication of highly ordered multilayer film structures from various types of materials in a controllable manner. This paper presents details of the preparation and functionalization of these materials and the techniques for the LbL assembly of different graphene-based nanocomposites using polymers and nanoparticles. We anticipate that the protocols presented in this paper will guide researchers in the reproducible assembly of various high-quality graphene-based nanocomposites for fundamental researches and for diverse potential applications.clos

An immunoassay utilizing the DNA-coated polydiacetylene micelles as a signal generator

Immunoassay is an important technique to detect the disease biomarkers and pathogenic biological agents which often present at low levels in clinical samples. To improve sensitivity of the immunoassay, here we described the DNA-coated, nano-sized micelles in which the DNA strands play a role as signal generators in an immunoassay. This micelle-based immunoassay was evaluated for quantitation of a liver cancer biomarker and the sensitivity of the method was compared with those of the conventional methods.close

Atomic-scale tailoring of chemisorbed atomic oxygen on epitaxial graphene for graphene-based electronic devices

Graphene, with its unique band structure, mechanical stability, and high charge mobility, holds great promise for next-generation electronics. Nevertheless, its zero bandgap challenges the control of current flow through electrical gating, consequently limiting its practical applications. Recent research indicates that atomic oxygen can oxidize epitaxial graphene in a vacuum without causing unwanted damage. In this study, we have investigated the effects of chemisorbed atomic oxygen on the electronic properties of epitaxial graphene using scanning tunneling microscopy (STM). Our findings reveal that oxygen atoms effectively modify the electronic states of graphene, resulting in a bandgap at its Dirac point. Furthermore, we demonstrate that it is possible to selectively induce desorption or hopping of oxygen atoms with atomic precision by applying appropriate bias sweeps with an STM tip. These results suggest the potential for atomic-scale tailoring of graphene oxide, enabling the development of graphene-based atomic-scale electronic devices. © 2023 Author(s).11Nsciescopu