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Giant magnetothermal anomalies and direct measurements of the magnetocaloric effect in Pr0.7Sr0.3_xBaxMnO3 manganites
No full textThe paper presents the results of a study of magnetization, specific heat (CP), thermal diffusivity (1), thermal conductivity (x) and direct measurements magnetocaloric effect of polycrystalline samples Pr0.7Sr0.3_xBaxMnO3 (x = 0-0.3). An increase in the Ba concentration leads to a decrease in the Curie temperature (TC), an increase in the disorder parameter (02) and a noticeable increase in thermal conductivity of the ferromagnetic phase (FM). The & kappa;(T) data near Tc revealed small minima and a sharp jump-like change in thermal conductivity upon transition to the FM phase. These results suggest that the anomalies in the temperature dependences of & eta;(T) and & kappa;(T) are associated with the scattering of thermal phonons both from distortions of the crystal lattice and from spin fluctuations. The giant change of & eta; (& UDelta;& eta;/& eta; -67%) and & kappa; (& UDelta;& kappa;/& kappa; -33%) was found in a magnetic field of 1.8 T for the x = 0 (Pr0.7Sr0.3MnO3) sample. The maximum values of & UDelta;T, & UDelta;S and relative cooling power (RCP), observed for this sample in a field of 1.8 T, are equal to 1.81 K, 3.38 J/kg K and 74.02 J/kg, respectively. In the studied Pr0.7Sr0.3_ xBaxMnO3 samples, the specific cooling power value at f = 0.2 Hz is 0.35, 0.29, 0.21, and 0.11 W/g for x = 0, 0.1, 0.2, and 0.3 sample, respectively
Explainable deep learning model for membrane capacitive deionization operated under fouling conditions
No full textTo avoid fouling problems during operation, membrane capacitive deionization (MCDI) requires proper cleaning processes. In this study, we assessed seven different conditions to investigate the effects of flushing conditions and foulant concentration on the recovery rate of the MCDI salt adsorption capacity. Two representative deep learning models, namely the long short-term memory (LSTM) and temporal fusion transformer (TFT) models, were developed to simulate effluent salt concentrations under fouling conditions. The prediction results obtained using the two models indicated that the TFT model (R2, 0.945-0.993; RMSE, 0.051-0.151) was superior to the LSTM model (R2, 0.631-0.993; RMSE, 0.051-0.740) in terms of performance and applicability. Analyses of the permutation importance and attention weights were performed to evaluate the importance of input variables and the model-training process. The interpretation of the models based on attention scores revealed that the TFT model used the applied voltage and implementation of flushing as important inputs, which contributed to higher prediction accuracy. Thus, the proposed model could be utilized as an interpretable artificial intelligence model in practical applications to improve the efficiency of MCDI operations involving flushing processes
Sensitive and highly rapid electrochemical measurement of airborne coronaviruses through condensation-based direct impaction onto carbon nanotube-coated porous paper working electrodes
No full textRapid detection of indoor airborne viruses is critical to prevent the spread of respiratory diseases. Herein, we present sensitive, highly rapid electrochemical measurement of airborne coronaviruses through condensation-based direct impaction onto antibody-immobilized, carbon nanotube-coated porous paper working electrodes (PWEs). Carboxylated carbon nanotubes are drop-cast on paper fibers to make three-dimensional (3D) porous PWEs. These PWEs have higher active surface area-to-volume ratios and electron transfer characteristics than conventional screen-printed electrodes. The limit of detection and detection time of the PWEs for liquid-borne coronaviruses OC43 are 65.7 plaque-forming units (PFU)/mL and 2 min, respectively. The PWEs showed sensitive and rapid detection of whole coronaviruses, which can be ascribed to the 3D porous electrode structure of the PWEs. Moreover, water molecules condense on airborne virus particles during air sampling, and these water-encapsulated virus particles (<4 ??m) are impacted on the PWE for direct measurement without virus lysis and elution. The whole detection takes ???10 min, including air sampling, at virus concentrations of 1.8 and 11.5 PFU/L of air, which can be due to the highly enriching and minimally damaging virus capture on a soft and porous PWE, demonstrating the potential for the rapid and low-cost airborne virus monitoring system
Flow-Assisted Ultrasonic Exfoliation Enabling Scalable and Rapid Graphene Production for Efficient Inkjet-Printable Graphene Ink
No full textAchieving high efficiency in graphene production andprinting processsimultaneously is challenging, but it needs to be addressed as itis critical for realizing the commercial viability of printed graphenedevices. This study successfully substantiates these requirementsby significantly improving the efficiency of graphene production andsubsequently developing an inkjet-printable graphene ink that enablesthe rapid formation of the percolation network of graphene flakes.The integration of a flow coil reactor into an ultrasonic bath resultsin scalable and rapid graphene production, with graphene productivityup to three orders of magnitude higher than conventional liquid-phaseexfoliation (LPE), offering the potential that ultrasonic LPE canbenefit the scalability and simplicity of graphene production. Inaddition, the graphene ink, optimized by ink formulation, has a stablehigh graphene concentration of 3.5 g L-1, resultingin the formation of stable percolation networks of graphene flakesonly after two printing passes under optimized printing conditions.The printed graphene patterns are also confirmed to be conformableto various substrates and durable against repeated stretching andbending stress. By ensuring high efficiency in graphene productionand inkjet-printable ink preparation, this study would promote thecommercialization of graphene production and the resulting printedgraphene devices
Minimally Invasive Implant Type Electromagnetic Biosensor for Continuous Glucose Monitoring System: In Vivo Evaluation
No full textObjective: Continuous glucose monitoring system (CGMS) is growing popular and preferred by diabetes over conventional methods of self-blood glucose monitoring (SBGM) systems. However, currently available commercial CGMS in the market is useful for few days to few months. This paper presents a durable, highly sensitive and minimally invasive implant type electromagnetic sensor for continuous glucose monitoring that is capable of tracking minute changes in blood glucose level (BGL). Methods: The proposed sensor utilizes strong oscillating nearfield to detect minute changes in dielectric permittivity of interstitial fluid (ISF) and blood due to changes in BGL. A biocompatible packaging material is used to cover the sensor. It helps in minimizing foreign body reactions (FBR) and improves stability of the sensor. Results: The performance of the proposed sensor was evaluated on live rodent models (C57BL/6J mouse and Sprague Dawley rat) through intravenous glucose and insulin tolerance tests. Biocompatible polyolefin was used as the sensor packaging material, and the effect of packaging thickness on the sensitivity of sensor was examined in in-vivo test. Proposed sensor could track real-time BGL change measured with a commercial blood glucose meter. High linear correlation (R-2 > 0.9) with measured BGL was observed during in vivo experiments. Conclusion: The experimental results demonstrate that the proposed sensor is suitable for long term CGMS applications with a high accuracy. Significance: Present work offers a new perspective towards development of long term CGM system using electromagnetic based implant sensor. The in vivo evaluation of the sensor shows excellent tracking of BGL changes
Empirical relationship between TEM-derived myelin volume fraction and MRI-R2 values in aging ex vivo rat corpus callosum
No full textEx vivo ratiometric measurements of short- and long-T2 components using the multiple spin echo sequence of MRI are often employed to evaluate alterations in myelin content in the white matter (WM) of the brain. However, the relationship between absolute MRI-T2 values (long-T2 component) and myelin volumetric information in aged ex vivo rodent WM appears to be influenced by factors such as animal species, field strength, and fixation durations/washing. Here, multiple spin echo sequence-based MRI-R2 (the reciprocal of T2) values were measured in the corpus callosum (CC) region in the post-mortem rat brains (n = 9) of different age groups with common fixation techniques without washing at 7 T. Transmission electron microscopy (TEM)-based quantification of myelin volume fraction (MVF) and corresponding Monte-Carlo simulation to estimate relaxation rates (R2,IE) due to diffusion in the presence of inhomogeneous magnetic field perturbation in intra- and extra-cellular (IE) spaces were respectively performed. To determine whether the short-T2 components originating from myelin water were mixed with long-T2 components from IE water or were undetectable, the MVF values obtained from TEM results were respectively compared with MRI-R2 and R2,IE values. A significant correlation (Pearson's correlation coefficient r = 0.8763; p < 0.01) of average MRI-R2 and MVF values was observed. Estimated R2,IE values from Monte-Carlo simulations in IE water signals were also positively correlated (r = 0.8281; p < 0.01) with MVF values. However, the magnitudes of R2,IE values were much smaller than those observed for MRI-R2 values, indicating that changes in R2 related MVF are likely dominated by myelin water components. Such comparisons between independent parameters from MRI, TEM, and simulations support the suggestion that myelin water signals were indistinguishably mixed to exhibit mono-exponential T2 relaxation, and multiple spin echo sequence-based MRI-R2 values in aging ex vivo rat CC without prolonged washing still reflect the volumetric information of myelin, likely due to enhanced water exchange across the myelin
Interface-Engineered Organic Near-Infrared Photodetector for Imaging Applications
No full textWe report a high-speed low dark current near-infrared(NIR) organicphotodetector (OPD) on a silicon substrate with amorphous indium galliumzinc oxide (a-IGZO) as the electron transport layer (ETL). In-depthunderstanding of the origin of dark current is obtained using an elaborateset of characterization techniques, including temperature-dependentcurrent-voltage measurements, current-based deep-level transient spectroscopy(Q-DLTS), and transient photovoltage decay measurements. These characterizationresults are complemented by energy band structures deduced from ultravioletphotoelectron spectroscopy. The presence of trap states and a strongdependency of activation energy on the applied reverse bias voltagepoint to a dark current mechanism based on trap-assisted field-enhancedthermal emission (Poole-Frenkel emission). We significantlyreduce this emission by introducing a thin interfacial layer betweenthe donor: acceptor blend and the a-IGZO ETL and obtain a dark currentas low as 125 pA/cm(2) at an applied reverse bias of -1V. Thanks to the use of high-mobility metal-oxide transport layers,a fast photo response time of 639 ns (rise) and 1497 ns (fall) isachieved, which, to the best of our knowledge, is among the fastestreported for NIR OPDs. Finally, we present an imager integrating theNIR OPD on a complementary metal oxide semiconductor read-out circuit,demonstrating the significance of the improved dark current characteristicsin capturing high-quality sample images with this technology
Development of Comprehensive Ultraperformance Liquid Chromatography-High-Resolution Mass Spectrometry Assays to Quantitate Cisplatin-Induced DNA-DNA Cross-Links
No full textCisplatin(CP) is a common antitumor drug that is usedto treatmany solid tumors. The activity of CP is attributed to the formationof DNA-DNA cross-links, which consist of 1,2-intra-, 1,3-intra-,and interstrand cross-links. To better understand how each intrastrandcross-link contributes to the activity of CP, we have developed comprehensiveultraperformance liquid chromatography-selective ion monitoring (UPLC-SIM)assays to quantify 1,2-GG-, 1,2-AG-, 1,3-GCG-, and 1,3-GTG-intrastrandcross-links. The limit of quantitation for the developed assays rangedfrom 5 to 50 fmol or as low as 6 cross-links per 10(8) nucleotides.To demonstrate the utility of the UPLC-SIM assays, we first performed in vitro cross-link formation kinetics experiments. We confirmedthat the 1,2-GG-intrastrand cross-links were the most abundant intrastrandcross-link and formed at a faster rate compared to 1,2-AG- and 1,3-intrastrandcross-links. Furthermore, we investigated the repair kinetics of intrastrandcross-links in CP-treated wild-type and nucleotide excision repair(NER)-deficient U2OS cells. We observed a slow decrease of both 1,2-and 1,3-intrastrand cross-links in wild-type cells and no evidenceof direct repair in the NER-deficient cells. Taken together, we havedemonstrated that our assays are capable of accurately quantifyingintrastrand cross-links in CP-treated samples and can be utilizedto better understand the activity of CP
