948 research outputs found

    Prediction of compressive behavior of laser powder bed fusion processed TPMS lattices by linear regression analysis

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    Triply periodic minimal surface (TPMS) structures offer lightweight and high-stiffness solutions to different industrial applications. However, testing of these structures to calculate their mechanical properties is expensive. Therefore, it is important to predict the mechanical properties of these structures effectively. This study focuses on the effectiveness of using regression analysis and equations based on experimental results to predict the mechanical properties of diamond, gyroid, and primitive TPMS structures with different volume fractions and build orientations. Gyroid, diamond, and primitive specimens with three different volume fractions (0.2, 0.3, and 0.4) were manufactured using a laser powder bed fusion (LPBF) additive manufacturing process using three different build orientations (45°, 60°, and 90°) in the present study. Experimental and statistical results revealed that regression analysis and related equations can be used to predict the mass, yield stress, elastic modulus, specific energy absorption, and onset of densification values of TPMS structures with an intermediate volume fraction value and specified build orientation with an error range less than 1.4%, 7.1%, 19.04%, 21.6%, and 13.4%, respectively

    Impedimetric detection of miRNA biomarkers using paper-based electrodes modified with bulk crystals or nanosheets of molybdenum disulfide

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    Paper-based electrodes modified with molybdenum disulfide (MoS2) in the form of bulk crystals or exfoliated nanosheets were developed and used as a biosensing platform for the impedimetric detection of miRNAs (miRNA-155 and miRNA-21) related to early diagnosis of lung cancer. For this purpose, MoS2 crystals or nanosheets were used for the modification of the working electrode area of paper-based platform for the first time in this study. The proposed assay offers sensitive and selective detection of microRNAs by electrochemical impedance spectroscopy (EIS) technique. The entire assay, both the electrode modification and the miRNA detection being completed in 30 min and a single sample droplet (5 mu L) was enough to cover working electrode area which enabled analysis in low sample volumes. The limits of detection (LOD) for miRNA-21 and miRNA-155 were calculated both in buffer and fetal bovine serum media. It is found that the LOD is varying between 1 and 200 ng/mL. In comparison to nanosheets, a larger electroactive surface area was obtained with bulk MoS2 resulting in lower LOD values on miRNA detection. The paper-based electrodes showed high specificity towards their target sequences. Moreover, they effectively discriminated single base mismatched non-target sequences. The advantages of these MoS2 paper based electrodes include high sensitivity, and low-cost provide great potential for improved monitoring of miRNA biomarkers even in artificial serum media.Newton-Katip Celebi funding program; Turkish Scientific and Technological Research Council TUBITAK [215Z702]; British Council [216182787]; Turkish Academy of Sciences (TUBITAK); Invest Northern Ireland under a Biodevices grant [RD0714186]; TUBITAK [215Z702]This project was supported by the Newton-Katip Celebi funding program, and authors acknowledge financial support from the Turkish Scientific and Technological Research Council TUBITAK Project no. 215Z702) and the British Council (Newton Fund, Institutional Links, Ref: 216182787). A.E. would also like to express her gratitude to the Turkish Academy of Sciences (TUBA) as a principal member for its partial support. E.Y. and E.E., master's students and PhD, respectively, acknowledge a project scholarship (TUBITAK Project no. 215Z702). Authors also acknowledge to helpful discussion of Assoc. Prof. Yildiz Uludag as the project consultant during project (TUBITAK; Project no. 215Z702). P.P. acknowledges support from Invest Northern Ireland under a Biodevices grant, Ref. RD0714186

    Effect of ornithine on the ileal histology, nitric oxide production and lipid peroxidation in LPS-induced endotoxemia.

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    Effect of ornithine which is known to inhibit L-arginine uptake via cationic amino acid transport system has been tested, and compared to aminoguanidine, an iNOS inhibitor in lypopolysaccharide (LPS)-induced endotoxemia in rats. Serum nitrite/nitrate and malondialdehyde (MDA) level have been measured, and ileal histology has also been examined. Endotoxin increased serum nitrite/nitrate and MDA levels from 15.7+/- 2.4 micromol/ml and 2.1 +/-0.2 nmol/ml to 23.1 +/- 1.0 micromol/ml and 5.2+/- 0.3 nmol/ml (both P&#60;0.05), respectively. In addition, LPS caused ileal degeneration. L-ornithine (500 mg/kg) did not improve septic manifestations, i.e., serum nitrite/nitrate and MDA levels did not differ from those in endotoxemia. Neither does it have an improving action on ileal histology. However, higher dose of L-ornithine (2,500 mg/kg) lowered the increased level of nitrite/nitrate and MDA by LPS. Moreover, it restored ileal histology from grade 3 (median) to 0 (median) (P&#60;0.05). On the other hand, aminoguanidine (100 mg/kg) normalized serum nitrite/nitrate and MDA levels but not ileal histology in endotoxemic rats. In conclusion, high dose of L-ornithine could improve endotoxemic parameters in LPS-treated rats.</p

    Paper-Based Electrochemical Biosensors for Voltammetric Detection of miRNA Biomarkers Using Reduced Graphene Oxide or MoS 2 Nanosheets Decorated with Gold Nanoparticle Electrodes

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    Paper-based biosensors are considered simple and cost-efficient sensing platforms for analytical tests and diagnostics. Here, a paper-based electrochemical biosensor was developed for the rapid and sensitive detection of microRNAs (miRNA-155 and miRNA-21) related to early diagnosis of lung cancer. Hydrophobic barriers to creating electrode areas were manufactured by wax printing, whereas a three-electrode system was fabricated by a simple stencil approach. A carbon-based working electrode was modified using either reduced graphene oxide or molybdenum disulfide nanosheets modified with gold nanoparticle (AuNPs/RGO, AuNPs/MoS2) hybrid structures. The resulting paper-based biosensors offered sensitive detection of miRNA-155 and miRNA-21 by differential pulse voltammetry (DPV) in only 5.0 ”L sample. The duration in our assay from the point of electrode modification to the final detection of miRNA was completed within only 35 min. The detection limits for miRNA-21 and miRNA-155 were found to be 12.0 and 25.7 nM for AuNPs/RGO and 51.6 and 59.6 nM for AuNPs/MoS2 sensors in the case of perfectly matched probe-target hybrids. These biosensors were found to be selective enough to distinguish the target miRNA in the presence of single-base mismatch miRNA or noncomplementary miRNA sequences

    Aktivna deformacija Zemljine povrơine utvrđena preciznim nivelmanskim premjerom u Afyon-AkƟehir grabenu u Zapadnoj Anadoliji u Turskoj

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    In the actively deforming region of western Anatolia, crustal deformation is accommodated by destructive earthquakes and a variety of aseismic events. In this study, we investigated the 2016–2017 aseismic sequence located in the Bolvadin Fault, one of the segments of the AkƟehir-Simav Fault System of western Anatolia by analysing surface deformation derived from detailed geological mapping. Our findings suggest that surface deformation in the Bolvadin Fault is accommodated by aseismic episodes. During the field studies in the Bolvadin area, progressive surface deformations, such as surface faults and earth fissures with a length of 800 meters to 3 kilometres and strike of N15°E to N70°E were mapped on a 1/5000 scale. Furthermore, a levelling network was established to calculate the vertical displacements and deformation rate along the surface deformations. Precision level measurements were undertaken in 2016 and 2017. On the routes to the NW of the Bolvadin settlement, a vertical deformation rate of 30 mm/yr was detected in the period of 2016–2017, and a large deformation rate of 40 mm/yr was detected in the same period.Aktivna deformacija Zemljine kore se u regiji Zapadne Anadolije kompenzira razornim potresima i drugim seizmičkim događajima. U ovom smo radu na temelju detaljnog geoloĆĄkog kartiranja analizirali deformaciju povrĆĄine kako bismo proučili niza seizmičkih događaja u razdoblju 2016.–2017. na lokaciji rasjeda Bolvadin, jednoga od segmenata rasjednoga sustava AkƟehir-Simav u Zapadnoj Anadoliji. NaĆĄi rezultati ukazuju na to da se povrĆĄinska deformacije kompenzira tijekom aseizmičkih epizoda. Tijekom terenskih istraĆŸivanja u području Bolvadin, progresivne su povrĆĄinske deformacije, poput povrĆĄinskih rasjeda ili pukotina duljina od 800 m do 3 km, pruĆŸanja N15°E do N70°E, kartirane u mjerilu 1:5 000. Nadalje, uspostavljena je nivelmanska mreĆŸa kako bi se izmjerila brzina pomaka i deformacija. Precizna nivelmanska mjerenja izvedena su 2016. i 2017. godine. Na pravcima usmjerenima SZ od naselja Bolvadin, ustanovljena je brzina vertikalne deformacije od 30 mm/god., a u istom je razdoblju izmjerena i velika brzina deformacije od 40 mm/god

    Platform agnostic electrochemical sensing app and companion potentiostat

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    Electrochemical sensing is ubiquitous in a number of fields ranging from biosensing, to environmental monitoring through to food safety and battery or corrosion characterisation. Whereas conventional potentiostats are ideal to develop assays in laboratory settings, they are in general, not well-suited for field work due to their size and power requirements. To address this need, a number of portable battery-operated potentiostats have been proposed over the years. However, most open source solutions do not take full advantage of integrated circuit (IC) potentiostats, a rapidly evolving field. This is partly due to the constraining requirements inherent to the development of dedicated interfaces, such as apps, to address and control a set of common electrochemical sensing parameters. Here we propose the PocketEC, a universal app that has all the functionalities to interface with potentiostat ICs through a user defined property file. The versatility of PocketEC, developed with an assay developer mindset, was demonstrated by interfacing it, via Bluetooth, to the ADuCM355 evaluation board, the open-source DStat potentiostat and the Voyager board, a custom-built, small footprint potentiostat based around the LMP91000 chip. The Voyager board is presented here for the first time. Data obtained using a standard redox probe, Ferrocene Carboxylic Acid (FCA) and a silver ion assay using anodic stripping multi-step amperometry were in good agreement with analogous measurements using a bench top potentiostat. Combined with its Voyager board companion, the PocketEC app can be used directly for a number of wearable or portable electrochemical sensing applications. Importantly, the versatility of the app makes it a candidate of choice for the development of future portable potentiostats. Finally, the app is available to download on the Google Play store and the source codes and design files for the PocketEC app and the Voyager board are shared via Creative Commons license (CC BY-NC 3.0) to promote the development of novel portable or wearable applications based on electrochemical sensing

    High-Capacity Conductive Nanocellulose Paper Sheets for Electrochemically Controlled Extraction of DNA Oligomers

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    Highly porous polypyrrole (PPy)-nanocellulose paper sheets have been evaluated as inexpensive and disposable electrochemically controlled three-dimensional solid phase extraction materials. The composites, which had a total anion exchange capacity of about 1.1 mol kg−1, were used for extraction and subsequent release of negatively charged fluorophore tagged DNA oligomers via galvanostatic oxidation and reduction of a 30–50 nm conformal PPy layer on the cellulose substrate. The ion exchange capacity, which was, at least, two orders of magnitude higher than those previously reached in electrochemically controlled extraction, originated from the high surface area (i.e. 80 m2 g−1) of the porous composites and the thin PPy layer which ensured excellent access to the ion exchange material. This enabled the extractions to be carried out faster and with better control of the PPy charge than with previously employed approaches. Experiments in equimolar mixtures of (dT)6, (dT)20, and (dT)40 DNA oligomers showed that all oligomers could be extracted, and that the smallest oligomer was preferentially released with an efficiency of up to 40% during the reduction of the PPy layer. These results indicate that the present material is very promising for the development of inexpensive and efficient electrochemically controlled ion-exchange membranes for batch-wise extraction of biomolecules

    MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

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    Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

    Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

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    A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

    Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

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    The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe
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