Signal-to-Noise Ratio Enhancement Using Graphene-Based Passive Microelectrode Arrays

This work is aimed toward the goal of investigating the influence of different materials on the signal-to-noise ratio (SNR) of passive neural microelectrode arrays (MEAs). Noise reduction is one factor that can substantially improve neural interface performance. The MEAs are fabricated using gold, indium tin oxide (ITO), and chemical vapor deposited (CVD) graphene. 3D-printed Nylon reservoirs are then adhered to the glass substrates with identical MEA patterns. Reservoirs are filled equally with a fluid that is commonly used for neuronal cell culture. Signal is applied to glass micropipettes immersed in the solution, and response is measured on an oscilloscope from a microprobe placed on the contact pad external to the reservoir. The time domain response signal is transformed into a frequency spectrum, and SNR is calculated from the ratio of power spectral density of the signal to the power spectral density of baseline noise at the frequency of the applied signal. We observed as the magnitude or the frequency of the input voltage signal gets larger, graphene-based MEAs increase the signal-to-noise ratio significantly compared to MEAs made of ITO and gold. This result indicates that graphene provides a better interface with the electrolyte solution and could lead to better performance in neural hybrid systems for in vitro investigations of neural processes

Fully Inkjet-Printed Multilayered Graphene-Based Flexible Electrodes for Repeatable Electrochemical Response

Graphene has proven to be useful in biosensing applications. However, one of the main hurdles with printed graphene-based electrodes is achieving repeatable electrochemical performance from one printed electrode to another. We have developed a consistent fabrication process to control the sheet resistance of inkjet-printed graphene electrodes, thereby accomplishing repeatable electrochemical performance. Herein, we investigated the electrochemical properties of multilayered graphene (MLG) electrodes fully inkjet-printed (IJP) on flexible Kapton substrates. The electrodes were fabricated by inkjet printing three materials – (1) a conductive silver ink for electrical contact, (2) an insulating dielectric ink, and (3) MLG ink as the sensing material. The selected materials and fabrication methods provided great control over the ink rheology and material deposition, which enabled stable and repeatable electrochemical response: bending tests revealed the electrochemical behavior of these sensors remained consistent over 1000 bend cycles. Due to the abundance of structural defects (e.g., edge defects) present in the exfoliated graphene platelets, cyclic voltammetry (CV) of the graphene electrodes showed good electron transfer (k = 1.125 × 10−2 cm s−1) with a detection limit (0.01 mM) for the ferric/ferrocyanide redox couple, [Fe(CN)6]−3/−4, which is comparable or superior to modified graphene or graphene oxide-based sensors. Additionally, the potentiometric response of the electrodes displayed good sensitivity over the pH range of 4–10. Moreover, a fully IJP three-electrode device (MLG, platinum, and Ag/AgCl) also showed quasi-reversibility compared to a single IJP MLG electrode device. These findings demonstrate significant promise for scalable fabrication of a flexible, low cost, and fully-IJP wearable sensor system needed for space, military, and commercial biosensing applications

「緩和ケアを推進する看護師教育プログラム」の評価 : 修了者およびその上司への調査から

京都府立医科大学医学部看護学科京都府立医科大学附属病院看護部京都府立医科大学看護実践キャリア開発センター京都府立医科大学附属病院地域医療推進部School of Nursing, Kyoto Prefectural University of MedicineDepartment of Nursing, University Hospital Kyoto Prefectural University of MedicineKyoto Prefectural University of Medicine, Career Development Center for NursingPromotion Division of Regional Medicine, University Hospital Kyoto Prefectural University of Medicine　本研究の目的は、「緩和ケア実践看護師養成コース（以下Aコース）」「在宅緩和ケア推進看護師養成コース（以下Bコース）」を受講した修了者とその上司への調査からプログラム評価および看護実践への活用状況を指標にしてプログラムを評価することである。【方法】平成27～31年度の間に京都府立医科大学看護実践キャリア開発センターが開催する「緩和ケアを推進する看護師教育プログラム」のAコースまたはBコースを受講した修了者25名のうち、調査時点で受講時と同じ施設・病院で就労を継続している21名（Aコース14名、Bコース7名）、とその上司21名（Aコース14名、Bコース7名）を研究対象者とした。修了生の施設・病院に質問紙を郵送し、令和3年7月～8月に無記名の自記式質問紙調査を行った。調査項目は、基本属性、カリキュラムについて、教育目標について、受講内容の適切性について、学習内容の臨床での活用について、とした。なお所属する大学の医学倫理審査委員会の承認を得て実施した（ERB-E-444）。【結果】回答者は、Aコース修了者9名、Aコース上司7名、Bコース修了者5名、Bコース上司3名であった。受講した修了者の評価においては、プログラムの内容についてAコースの8割以上が、Bコースの全員が（とても・まあまあ）適切としている。自己能力の発揮状況について、Aコースは4～6割、Bコースについては4～8割ができているとしている。　上司からの評価では、両コースとも受講した講義・演習・実習が7割程度現在の看護実践に役立っていると答えた。期待される能力については両コースとも8割以上が現在の看護活動に活きていると答えた。【結論】平成27年度から開始された「緩和ケアを推進する看護師教育プログラム」に対して、受講した修了者とその上司に，研修が有用であったかを問うたところ、受講した修了者はプログラムの内容が看護の実践で活かされていると実感していることが明らかとなった。さらに、上司は、受講した修了者が研修を踏まえた看護実践ができていると評価していることが明らかになった。修了者、上司の評価からプログラムの効果を評価することができた

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

The Effects of Colloidal C60 Particle Size on Zeta Potential

Multiple methods are used to synthesize C60 to what is believed to be its most environmentally and biologically relevant form, an aqueous colloidal suspension (nC60). Stability of the suspension is attributed to a relatively large negative zeta potential that has been shown to develop upon the formation of nC60. Investigations of the spontaneous development of this negative surface charge have provided partial explanations towards the identification of its origin, but a mechanism that completely identifies it has yet to be actualized. A relatively uncontrollable variable in nC60 formation, size, is investigated to help elucidate this mechanism. Four different synthesis methods were evaluated to determine the effects, if any, that particle size has on zeta potential. Aqueous suspensions from each method were subjected to a particle-by-particle zeta potential analysis using NanoSight Model NS500HSB. Zeta potential as it relates to particle size will be discussed

Computational Methods for Bullvalene

Tricyclo(3.3.2.0)deca-2,7,9-triene (bullvalene) is a unique molecule in that all of its bond are constantly rearranging. This constant rearrangement is also is known as the cope rearrangement. The kinetic parameters of this rearrangement have been determined experimentally, but the computational method that demonstrates the highest accuracy for this system has yet to be determined. The initial determination of the ground state and transition state of bullvalene were determined through ab initio methods using the 6-311G++ basis set. The Gaussian and Complete Basis Set methods were used to calculate the kinetic parameters of bullvalene’s ground and transition state. The accuracy was determined from comparison to previously reported experimental values

Additive Manufacturing of Sensors for Extreme Environments

Advanced manufacturing based direct-write technologies have emerged as the predominant enabler for the fabrication of active and passive sensors for use in harsh operating environments. The ability to directly write and integrate electronic components onto physical packaging can be achieved with additive manufacturing (AM) methods such as direct write technologies (DWT) which include aerosol jet printing (AJP), Ink Jet Printing (IJP), Plasma Jet Printing (PJP), and Micro-Dispense Printing (MDP). In this work, we investigate the use of these methods to accelerate, modernize, and enhance the functionality of sensors and instrumentation to achieve the goal of improving the safety and efficiency of processes that take place within harsh environments. This dissertation accomplishes these objectives with the following activities: (1) an investigation targeting structural health monitoring of space habitats with the development of AJP capacitive strain gauges, (2) an investigation on the melt behavior of AM melt wires by benchmarking the performance of AM melt wires to their classically fabricated counterparts for peak temperature monitoring in nuclear reactors, and (3) the development of AM neutron dosimeters for directional flux monitoring in the TREAT reactor. The results from these activities highlight DWTs as potential solutions for the development of miniature and robust sensors that are difficult to achieve with traditional fabrication methods for nuclear and aerospace instrumentation

High-Temperature, Dynamic Strain Test Platform to Evaluate Capacitance Based Strain Gauges for In-Pile Deployment

This paper presents a test platform capable of applying representative in-pile thermal and monotonic, cyclic, and dynamic force loadings which induce target strain into representative in-pile components. The system\u27s form is that of two concentric linear delta robots and an intermediate vertical furnace. The enabled relative motion between the end effector platforms will result in enhanced performance compared to single delta or nearly any other Cartesian translational system by doubling the speed, quadrupling the workspace, and being able to actively prevent vibrational damage to its mechanical components. The employed force/torque sensors and motors are sized to apply/measure the target ranges, sensitivities, and bandwidths representative of in-pile loadings for objects of interest. The system has been designed to accommodate many in-pile geometries including a conventional (15mm OD x 12mm ID) fuel pin. Collet chucks attached to the force/torque sensors are designed to secure the pin ends as it transgresses through a furnace tube cavity allowing it to be thermally and/or force loaded. Such a configuration allows material characterization and sensor qualification/development to be performed. The system\u27s current configuration will have the ability to execute a comprehensive thermal and force loaded strain gauge study. Considered strain gauges in this future study will include conventional resistive strain gauges, weldable resistive strain gauges, and printed capacitive based strain gauges. The printed capacitive strain gauges being developed by this effort are of highest interest due to preliminary results indicating that their performance measures are more compatible with in-pile environments than their commercial counterparts. The test platform will be a critical element in validating the performance of the employed nuclear grade inks for aerosol jet printing, the printing and physical characterization of the printed structures, and the evaluation of sensor performance pre and post-irradiation

Additive Manufacturing of Miniaturized Peak Temperature Monitors for In-Pile Applications

Passive monitoring techniques have been used for peak temperature measurements during irradiation tests by exploiting the melting point of well-characterized materials. Recent efforts to expand the capabilities of such peak temperature detection instrumentation include the development and testing of additively manufactured (AM) melt wires. In an effort to demonstrate and benchmark the performance and reliability of AM melt wires, we conducted a study to compare prototypical standard melt wires to an AM melt wire capsule, composed of printed aluminum, zinc, and tin melt wires. The lowest melting-point material used was Sn, with a melting point of approximately 230 °C, Zn melts at approximately 420 °C, and the high melting-point material was aluminum, with an approximate melting point of 660 °C. Through differential scanning calorimetry and furnace testing we show that the performance of our AM melt wire capsule was consistent with that of the standard melt-wire capsule, highlighting a path towards miniaturized peak-temperature sensors for in-pile sensor applications