2,126 research outputs found

    A numerical study of added resistance, speed loss and added power of a surface ship in regular head waves using coupled urans and rigid-body motion equations

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    Coupled solutions of two-phase Unsteady Reynolds-Averaged Navier-Stokes equations (URANS) and six degrees-of-freedom (6-DOF) rigid-body motion (RBM) equations are pursued to compute ship’s speed loss and added power for a self-propelling ship in regular head sea. A case study is presented fora 1/49 scalemodel of the ONR Tumblehome (ONRT) (Model 5613)which was tested in the towing tank of the Iowa Institute of Hydraulic Research (IIHR). The computations were carried out for various combinations oftowed and self-propelled conditions, and in calm water and regular head waves witha rangeof wave length and amplitude.Thecase study demonstrates that the coupled URANS and RBM solution approach can predict added resistance, speed loss and added power of a ship cruising in head waves with commendable accuracy and shed light onthecomplex interactions among the ship,propeller, waves andflow-fields

    The Effect of Herbal Diet on Skeletal Muscle Mass After Resistance Training in Rats

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    Resistance training has been well established as an effective strategy for muscle hypertrophy, increase in skeletal muscle mass and strength. Herbal diet has been introduced as an alternative treatment to alleviate muscle atrophy and therapeutic intervention. However, there is little evidence on the effect of herbal diet on skeletal muscle mass. To investigate whether herbal diet affects skeletal muscle mass after resistance training in rats. Twenty-four rats were randomly divided into 3 groups: 1) Control (CON, N=8), 2) Resistance training (RT, N=8), 3) RT+Herb (RTH, N=8). Resistance training was performed every other day for 8 weeks using ladder climbing. The ladder climbing exercise consisted of 3 sets of 5 repetitions with a 1 min rest interval between the repetitions and a 2 min rest between the sets. Huang Qi (Radix Astragali Membranceus) was given via oral gavage once a day for 8 weeks (1 ml mixed with water based on concentration of 368 mg/kg). All rats received sham treatment, same as treatment groups. All data were analyzed using One-way ANOVA. After 8 weeks of interventions, muscle mass of Gastrocnemius, Plantaris, and Flexor hallucis longus showed significant increases in RT and RTH groups compared to CON (

    Dedicated preparation for in situ transmission electron microscope tensile testing of exfoliated graphene

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    Graphene, which is one of the most promising materials for its state-of-the-art applications, has received extensive attention because of its superior mechanical properties. However, there is little experimental evidence related to the mechanical properties of graphene at the atomic level because of the challenges associated with transferring atomically-thin two-dimensional (2D) materials onto microelectromechanical systems (MEMS) devices. In this study, we show successful dry transfer with a gel material of a stable, clean, and free-standing exfoliated graphene film onto a push-to-pull (PTP) device, which is a MEMS device used for uniaxial tensile testing in in situ transmission electron microscopy (TEM). Through the results of optical microscopy, Raman spectroscopy, and TEM, we demonstrate high quality exfoliated graphene on the PTP device. Finally, the stress???strain results corresponding to propagating cracks in folded graphene were simultaneously obtained during the tensile tests in TEM. The zigzag and armchair edges of graphene confirmed that the fracture occurred in association with the hexagonal lattice structure of graphene while the tensile testing. In the wake of the results, we envision the dedicated preparation and in situ TEM tensile experiments advance the understanding of the relationship between the mechanical properties and structural characteristics of 2D materials

    MOF-Derived Cu@Cu2O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

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    Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu2O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions

    Advancing Patient Care: Innovative Use of Near-Infrared Spectroscopy for Monitoring Urine Volume in Neurogenic Bladder

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    Purpose Current guidelines recommend clean intermittent catheterization (CIC) at regular time intervals for patients with spinal cord injuries; however, many patients experience difficulties. Performing time-based CIC outside the home is a significant burden for patients. In this study, we aimed to overcome the limitations of the current guidelines by developing a digital device to monitor bladder urine volume in real-time. Methods The optode sensor is a near-infrared spectroscopy (NIRS)-based wearable device intended to be attached to the skin of the lower abdomen where the bladder is located. The sensor’s primary function is to detect changes in urine volume within the bladder. An in vitro study was conducted using a bladder phantom that mimicked the optical properties of the lower abdomen. To validate the data in the human body at the proof-of-concept level, one volunteer attached the device to the lower abdomen to measure the light intensity between the first voiding and immediately before the second voiding. Results The degree of attenuation at the maximum test volume was equivalent across experiments, and the optode sensor with multiplex measurements demonstrated robust performance for patient diversity. Moreover, the symmetric feature of the matrix was deemed a potential parameter for identifying the accuracy of sensor localization in a deep-learning model. The validated feasibility of the sensor showed almost the same results as an ultrasound scanner, which is routinely used in the clinical field. Conclusions The optode sensor of the NIRS-based wearable device can measure the urine volume in the bladder in real-time

    Depression and suicide risk prediction models using blood-derived multi-omics data

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    More than 300 million people worldwide experience depression; annually, ~800,000 people die by suicide. Unfortunately, conventional interview-based diagnosis is insufficient to accurately predict a psychiatric status. We developed machine learning models to predict depression and suicide risk using blood methylome and transcriptome data from 56 suicide attempters (SAs), 39 patients with major depressive disorder (MDD), and 87 healthy controls. Our random forest classifiers showed accuracies of 92.6% in distinguishing SAs from MDD patients, 87.3% in distinguishing MDD patients from controls, and 86.7% in distinguishing SAs from controls. We also developed regression models for predicting psychiatric scales with R2 values of 0.961 and 0.943 for Hamilton Rating Scale for Depression???17 and Scale for Suicide Ideation, respectively. Multi-omics data were used to construct psychiatric status prediction models for improved mental health treatment

    Weave Lamp

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    The lamp is created using four materials. The lampshade is constructed using electrical cables and wires, which are removed from computer cables. These wires are weaved and form a cylindrical shape to surround the light. The base is created using monitor baseboards/stands, and eight metal rods are connected to the baseboard to support the lampshade. Lastly, the bulb is connected to the lamp socket, located above the baseboard. The angle of the lamp can also be adjusted by sliding the body to its right or left.Ope

    In situ electrochemical surface modification for high-voltage LiCoO2 in lithium ion batteries

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    High-voltage LiCoO2 has been revisited to improve the energy density of lithium ion batteries. LiCoO2 can deliver the reversible capacity of about 200 mA h g(-1) when the upper cut-off voltage increases to 4.55 V (vs. Li/Li+). However, the high upper cut-off voltage causes the severe failures of LiCoO2 such as structural degradation, electrolyte decomposition, and Co dissolution. Various surface-modified LiCoO2 materials have been introduced to suppress electrolyte decomposition and Co dissolution, thereby leading to the improved electrochemical performance. Most of the coated LiCoO2 materials are obtained through a conventional coating process such as sol-gel synthesis, which is complex and high-cost. In this paper, the in situ electrochemical coating method is introduced as a simple and low-cost coating process, where the electrolyte additive of Mg salts is electrochemically decomposed to form a MgF2-based coating layer on the LiCoO2 surface. LiCoO2 electrochemically coated with MgF2 suppresses Co dissolution in electrolytes, resulting in excellent electrochemical performance such as high reversible capacity of 198 mA h g(-1) and stable cycle performance over 100 cycles in the voltage range between 3 and 4.55 V (vs. Li/Li+) at 45 degrees C. The formation mechanism of MgF2 is also demonstrated through ex situ XPS and XANES analyses.

    A Minimal TrpRS Catalytic Domain Supports Sense/Antisense Ancestry of Class I and II Aminoacyl-tRNA Synthetases

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    The emergence of polypeptide catalysts for amino acid activation, the slowest step in protein synthesis, poses a significant puzzle associated with the origin of biology. This problem is compounded as the 20 contemporary aminoacyl-tRNA synthetases belong to two quite distinct families. We describe here the use of protein design to show experimentally that a minimal class I aminoacyl-tRNA synthetase active site might have functioned in the distant past. We deleted the anticodon binding domain from tryptophanyl-tRNA synthetase and fused the discontinuous segments comprising its active site. The resulting 130 residue minimal catalytic domain activates tryptophan. This residual catalytic activity constitutes the first experimental evidence that the conserved class I signature sequences, HIGH and KMSKS, might have arisen in-frame, opposite motifs 2 and 1 from class II, as complementary sense and antisense strands of the same ancestral gene
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