A gel polymer electrolyte (GPE) is a liquid electrolyte (LE) entrapped by a small amount of polymer network less than several wt%, which is characterized by properties between those of liquid and ...solid electrolytes in terms of the ionic conductivity and physical phase. Electrolyte leakage and flammability, demerits of liquid electrolytes, can be mitigated by using GPEs in electrochemical cells. However, the contact problems between GPEs and porous electrodes are challenging because it is difficult to incorporate GPEs into the pores and voids of electrodes. Herein, the focus is on GPEs that are gelated in situ within cells instead of covering comprehensive studies of GPEs. A mixture of LE and monomer or polymer in a liquid phase is introduced into a pre‐assembled cell without electrolyte, followed by thermal gelation based on physical gelation, monomer polymerization, or polymer cross‐linking. Therefore, GPEs are formed omnipresent in cells, covering the pores of electrode material particles, and even the pores of separators. As a result, different from ex situ formed GPEs, the in situ GPEs have no electrode/electrolyte contact problems. Functional GPEs are introduced as a more advanced form of GPEs, improving lithium‐ion transference number or capturing transition metals released from electrode materials.
Gel polymer electrolytes characterized by in situ gelation are presented. Different from ex situ gelated GPEs outside of electrochemical cells, in situ GPEs are formed omnipresent within cells covering the pores of the electrode material particles, and even the pores of the separators. The merits of in situ GPEs are demonstrated in electrochemical energy systems such as lithium‐ion batteries and lithium–sulfur batteries.
The lithium metal battery has attracted considerable attention as the ultimate lithium secondary battery for high energy density. However, safety issues and battery performance deterioration due to ...the growth of lithium dendrites have hampered the practical use of lithium metal batteries. Recently, lithium fluoride has been considered as a lithium metal protective layer to solve this problem. In this review, firstly, the results of the studies on dendrites and SEI that have been carried out to date are reviewed. Secondly, the results of studies on lithium fluoride are divided into additive, artificial SEI, and other methods and the possibilities of their practical use are discussed. Finally, the significance and limitations of the lithium fluoride studies are summarized, and general conclusions and prospects for recommended research directions to accelerate the commercialization of lithium metal batteries are presented.
Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period.
We evaluated the viral dynamics in various body fluid ...specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR).
SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log
copies/mL; patient 2 = 7.49 log
copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log
copies/mL; patient 2 = 7.10 log
copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash.
SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.
Accurate analysis of specific biomarkers in clinical serum is essential for early diagnosis and treatment of cancer. Here, a surface-enhanced Raman scattering (SERS)-based immunoassay, using magnetic ...beads and SERS nano tags, was developed for the determination of free to total (f/t) prostate specific antigen (PSA) ratio to improve the diagnostic performance of prostate cancer. To assess the clinical applicability of the proposed method, SERS-based assays for the simultaneous detection of dual PSA markers, free PSA (f-PSA) and complexed PSA (c-PSA), were performed for clinical samples in the gray zone between 4.0 and 10.0 ng/mL. Our assay results for f/t PSA ratio showed a good linear correlation with those measured using the electrochemiluminescence (ECL) system installed in the clinical laboratory of the University Hospital. In addition, the simultaneous assay provided better precision than parallel assays for the detection of f-PSA and c-PSA in 13 clinical serum samples. Therefore, our SERS-based assay for simultaneous detection of dual PSA markers in clinical fluids has strong potential for application in the accurate diagnosis of prostate cancer.
There have been extensive efforts to synthesize crystalline covalent triazine‐based frameworks (CTFs) for practical applications and to realize their potential. The phosphorus pentoxide ...(P2O5)‐catalyzed direct condensation of aromatic amide instead of aromatic nitrile to form triazine rings. P2O5‐catalyzed condensation was applied on terephthalamide to construct a covalent triazine‐based framework (pCTF‐1). This approach yielded highly crystalline pCTF‐1 with high specific surface area (2034.1 m2 g−1). At low pressure, the pCTF‐1 showed high CO2 (21.9 wt % at 273 K) and H2 (1.75 wt % at 77 K) uptake capacities. The direct formation of a triazine‐based COF was also confirmed by model reactions, with the P2O5‐catalyzed condensation reaction of both benzamide and benzonitrile to form 1,3,5‐triphenyl‐2,4,6‐triazine in high yield.
A covalent triazine‐based framework was synthesized by phosphorus pentoxide (P2O5)‐catalyzed direct condensation of aromatic amides to form a triazine ring. Highly crystalline covalent triazine frameworks (pCTF‐1) were produced with high specific surface area (2034.1 m2 g−1). At low pressure, pCTF‐1 shows a high carbon dioxide (CO2) uptake capacity of 21.9 wt % at 273 K and a hydrogen (H2) uptake capacity of 1.75 wt % at 77 K.
Background
Currently, SARS‐CoV‐2 RNA detection using real‐time reverse‐transcription PCR (rRT‐PCR) is the standard diagnostic test for COVID‐19 infection. Various rRT‐PCR assays are currently used ...worldwide, targeting different genes of the SARS‐CoV‐2. Here, we compared the analytical sensitivity and clinical performance (sensitivity and specificity) of Allplex SARS‐CoV‐2/FluA/FluB/RSV assay (Seegene), Standard M nCoV real‐time detection kit (SD Biosensor), and U‐TOP COVID‐19 detection kit (Seasun Biomaterials) for SARS‐CoV‐2 detection.
Methods
Two hundred and forty‐nine nasopharyngeal swab samples were evaluated to compare the clinical performance of the rRT‐PCR assays. For the analytical performance evaluation, two RNA controls with known viral loads—SARS‐CoV‐2 RNA control and SARS‐COV‐2 B.1.351 RNA control—were used to investigate the potential impact of SARS‐CoV‐2 variants, particularly the B.1.351 lineage.
Results
Limits of detection ranged from 650 to 1300 copies/ml for rRT‐PCR assays, and the mean differences in cycle threshold (Ct) values of the two RNA controls were within 1.0 for each target in the rRT‐PCR assays (0.05–0.73), without any prominent Ct value shift or dropouts in the SARS‐COV‐2 B.1.351 RNA control. Using the consensus criterion as the reference standard, 89 samples were positive, whereas 160 were negative. The overall clinical performance of rRT‐PCR assays was comparable (sensitivity 98.88%–100%; specificity 99.38%–100%), whereas the sensitivities of each target gene were more variable.
Conclusions
The three rRT‐PCR assays showed comparable analytical sensitivity and clinical performance. The analytical and clinical sensitivities of each target gene were influenced more by the primer and probe design than the target gene itself.
For the analytical performance evaluation, two RNA controls with known viral loads—SARS‐CoV‐2 RNA control and SARS‐COV‐2 B.1.351 RNA control—were used to investigate the potential impact of SARS‐CoV‐2 variants, particularly the B.1.351 lineage. Limits of detection ranged from 650 to 1300 copies/ml for rRT‐PCR assays and the mean differences in cycle threshold (Ct) values of the two RNA controls were within 1.0 for each target in the rRT‐PCR assays (0.05–0.73), without any prominent Ct value shift or dropouts in the SARS‐CoV‐2 B.1.351 RNA control. The overall clinical performance of rRT‐PCR assays was comparable (sensitivity 98.88%–100%; specificity 99.38%–100%), whereas the sensitivities of each target gene were more variable. Both analytical and clinical performances of each target gene appear to be influenced more by the primer and probe design rather than the target gene. Clinical performance results were in line with the analytical sensitivity results. The S and ORF1ab genes were the most sensitive target genes using the Allplex SARS‐CoV‐2/FluA/FluB/RSV assay and U‐TOP COVID‐19 detection kit. In the case of the Standard M nCoV real‐time detection kit, although the difference in analytical sensitivity was not evident, RdRp showed higher sensitivity than the E gene.
Calcium‐ion batteries (CIBs) are considered to be promising next‐generation energy storage systems because of the natural abundance of calcium and the multivalent calcium ions with low redox ...potential close to that of lithium. However, the practical realization of high‐energy and high‐power CIBs is elusive owing to the lack of suitable electrodes and the sluggish diffusion of calcium ions in most intercalation hosts. Herein, it is demonstrated that calcium‐ion intercalation can be remarkably fast and reversible in natural graphite, constituting the first step toward the realization of high‐power calcium electrodes. It is shown that a graphite electrode exhibits an exceptionally high rate capability up to 2 A g−1, delivering ≈75% of the specific capacity at 50 mA g−1 with full calcium intercalation in graphite corresponding to ≈97 mAh g−1. Moreover, the capacity stably maintains over 200 cycles without notable cycle degradation. It is found that the calcium ions are intercalated into graphite galleries with a staging process. The intercalation mechanisms of the “calciated” graphite are elucidated using a suite of techniques including synchrotron in situ X‐ray diffraction, nuclear magnetic resonance, and first‐principles calculations. The versatile intercalation chemistry of graphite observed here is expected to spur the development of high‐power CIBs.
Graphite as a reliable anode material for calcium‐ion batteries is realized. By selecting a proper dimethylacetamide‐based electrolyte, reversible Ca (de)insertion is enabled in graphite at room temperature with large Ca‐storage capacities, remarkable reversibility, and exceptionally high power capability (≈75% capacity retention at 2 A g−1 to that at 50 mA g−1).
A novel deep-learning algorithm for artificial neural networks (ANNs), completely different from the back-propagation method, was developed in a previous study. The purpose of this study was to ...assess the feasibility of using the algorithm for the detection of intracranial haemorrhage (ICH) and the classification of its subtypes, without employing the convolutional neural network (CNN). For the detection of ICH with the summation of all the computed tomography (CT) images for each case, the area under the ROC curve (AUC) was 0.859, and the sensitivity and the specificity were 78.0% and 80.0%, respectively. Regarding ICH localisation, CT images were divided into 10 subdivisions based on the intracranial height. With the subdivision of 41-50%, the best diagnostic performance for detecting ICH was obtained with AUC of 0.903, the sensitivity of 82.5%, and the specificity of 84.1%. For the classification of the ICH to subtypes, the accuracy rate for subarachnoid haemorrhage (SAH) was considerably excellent at 91.7%. This study revealed that our approach can greatly reduce the ICH diagnosis time in an actual emergency situation with a fairly good diagnostic performance.
This study investigated the mechanical properties of ultra high performance fiber reinforced cementitious composites (UHPFRCC) with four different fiber volume fractions (Vf=1%, 2%, 3%, and 4%) ...within an identical mortar matrix. The higher amount of fiber resulted in an improvement of load carrying capacity and elastic modulus in compression up to 3vol.% of fibers. A higher pullout strength was obtained from the inclusion of fibers in the matrix, and 2vol.% of fibers provided the best performance in all aspects of fiber pullout behavior including average and equivalent bond strengths and pullout energy. The flexural strength was pseudo-linearly increased with increase in fiber volume fraction, despite an insignificant difference in the first cracking load. Furthermore, a bi-linear softening curve for UHPFRCC was suggested based on the result of inverse analysis, and it was verified through comparison with the experimental data.
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