Carbon- and Binder- Free Cathode for Lithium Oxygen Batteries

Department of Energy Engineering(BatteryScienceandTechnology)Unstable oil prices and the effects of global warming have forced us to look for alternative energy storage and conversion systems. So battery industry especially lithium ion battery (LIB) have been developed so fast. A battery is usually made up of an anode on one side, a cathode on the other, and an electrolyte (and separator) in between. For a LIB, lithium ions move from the anode to the cathode through the electrolyte, creating a chemical reaction that allows electrons to be harvested along the way. And very recently portable electronic devices and electric vehicle (EV) have been developing at a rapid pace, and these progress demand much high energy and power density. So metal-air batteries have been shed light on due to their high energy density and extremely high power compared to those of other conventional batteries. A metal air battery is a battery that could use a metal - lithium, aluminum, iron, or zinc etc.- for the anode, air (technically oxygen) as the cathode and electrolyte. Many people have interests in the metal air batteries because oxygen is abundant in nature, free, and doesn’t require a heavy casing to keep it inside a battery cell. Among metal-air batteries, metals such as Li, Al, Fe, and Zn, Zinc-air and Li-O2 batteries in particular have potential for use as alternative energy storage devices. Although other metals like Al can show much high voltage and power, Zn has various advantages such as low cost, abundance, low equilibrium potential, environmental benignity. The theoretical specific energy density of Zn-air batteries is 1084 Wh · kg-1. And Li-air (or Lithium Oxygen) battery; Although li metal is explosively reactive with water, the lithium Oxygen (Li-O2) battery has attracted interest because of its extremely high theoretical energy density, 11,140 Wh · kg-1 (excluding O2) and power density is 3505 Wh · kg-1, which is about eight times larger than that of conventional rechargeable lithium-ion batteries. The Zn-air and Li-O2 battery, however, have many problems in the case of Zn air battery; ohmic loss, carbon dioxide absorption and zinc dendrite formation and in the case of Li-O2 battery; a low current density, instability of nonaqueous electrolytes, and poor cycle ability etc. Moreover, carbon cathode can lead to the inevitable reactions between the discharge product Li2O2. In addition, several recent studies have reported about binders including PVDF which are necessary to make a carbon electrode also react with chemically generated LiO2. So in this PhD thesis, I studied on the problems of Li-O2 battery. And the possibility of carbon- and binder free cathodes for the Li-O2 battery has been studied. Gold (Au) and Silver (Ag) nanoparticles coated Ni nanowire substrate were used as electrodes (Au/Ni, Ag/Ni electrode) for Li-O2 battery. The Au/Ni electrode demonstrates improved capacity of ~ 600 mAh g-1Au. More importantly, it exhibited improved cyclability over 200 cycles at full discharge and charge condition between 2.3 V and 4.3 V. Meanwhile, since Ag is not electrochemically stable as much as Pt and Au at high voltages. It is needed to be found proper electrolytes for Ag/Ni electrode. The stability and performance of different electrolyte solvents were investigated such as 1,2-dimethoxyethane (DME), diethylene glycol dimethyl ether (DEGDME), tetraethylene glycol dimethyl ether (TEGDME), dimethylformamide (DMA), dimethyl sulfoxide (DMSO) or N-methyl-2-pyrrolidone (NMP). It was found that the NMP based electrolyte exhibits superior electrochemical properties. The Ag/Ni electrode with NMP/1M LiTFSI delivers a capacity of 473 mAhg-1Ag at 100 mAg-1Ag under between 2.3 V and 3.8 V and shows stable cycling performance until 35th with 300 mAhg-1Ag cut off condition at 100 mAg-1Ag.openhttp://unist.dcollection.net/jsp/common/DcLoOrgPer.jsp?sItemId=00000223689

1-Methyl-3-(4-vinyl­benz­yl)imidazolium hexa­fluoro­phosphate

In the title compound, C13H15N2 +·PF6 −, the dihedral angle between the two aromatic rings is 85.48 (7)°. In the crystal, C—H⋯F hydrogen bonds connect the imidazolium and hexa­fluoro­phosphate ions

Perceptions of health status, physical fitness, and participation in physical activity among adolescents before and after COVID-19: analysis of 2019‑2021 data from the Republic of Korea national sports survey

Research has examined the detrimental effects of the coronavirus disease (COVID-19) pandemic on health and physical fitness in adolescents; however, studies comparing these parameters before and after the COVID-19 outbreak have been scarce. Therefore, this study investigated differences in perceived health status, perceived physical fitness, and participation in physical activity among adolescents in the Republic of Korea before and after the COVID-19 outbreak. We chose a sample of data from 2102 adolescents aged 14–19, collected as part of a national survey by the Republic of Korea Ministry of Culture, Sports, and Tourism from 2019 to 2021. We focused on five items from the survey related to health awareness and physical activity. Although perceived health status was lower in 2021 than in 2019 or 2020, there were no differences in perceived physical fitness during the three years of the study. Regular participation in physical activity was less common in 2020 than in 2019 or 2021. The proportion of adolescents reporting sufficient rest and sleep was lower in 2021 than in 2020. In addition, fewer adolescents reported eating regular meals and engaging in nutritional supplementation in 2021 than in 2019 and 2020. Rates of abstinence from alcohol and smoking cessation were higher in 2021 than in 2019 or 2020. For all three years, adolescents reported the following as the primary reasons for engaging in regular physical activity (in order): “maintenance of mental health”, “maintenance of physical health”, “help in daily life”, and “reduction of medical expenses”. In preparation for the post-COVID-19 era, these results highlight the need to prepare measures and countermeasures to promote health and physical activity among adolescents in the Republic of Korea

Comprehensive analysis of mycobacterium tuberculosis antigen-specific CD4+ T cell responses restricted by single HLA class II allotype in an individual

Mycobacterium tuberculosis infection is generally asymptomatic as latent tuberculosis, but it is still known as the world’s leading bacterial cause of death. The diagnosis of latent tuberculosis infection relies on the evidence of cellular immunity to mycobacterial antigens. Since the association between HLA class II and tuberculosis infection has been reported in several population groups, a detailed study on the CD4+ T cell response to major tuberculosis antigens is needed. To elucidate which HLA class II allotypes in an individual are preferentially used in tuberculosis, CD4+ T cells specific to TB10.4, Ag85b, ESAT-6, and CFP-10 of Mycobacterium tuberculosis antigens were analyzed comprehensively. A total of 33 healthy donors were analyzed by ex vivo and cultured ELISPOT using panels of artificial antigen-presenting cells expressing a single HLA class II allotype. The CD4+ T cell responses were increased by an average of 39-fold in cultured ELISPOT compared with ex vivo ELISPOT. In ex vivo and cultured ELISPOT, CD4+ T cell responses showed significantly higher by HLA-DR than those of HLA-DQ and HLA-DP locus. In cultured ELISPOT, 9 HLA-DR allotypes, 4 HLA-DQ allotypes, and 3 HLA-DP allotypes showed positive CD4+ T cell responses. Among ten donors with positive CD4+ T cell responses when tested for mixed Mycobacterium tuberculosis antigens, seven donors were positive for only a single allotype, and three were positive for two allotypes in an individual. However, only one allotype was used for a single antigen-specific response when a single tuberculosis antigen was used individually. These results on the distribution of HLA class II allotypes showing high CD4+ T-cell responses to Mycobacterium tuberculosis antigens and the intra-individual allotype dominance will provide valuable information for understanding the immunobiology and immunogenetics of tuberculosis, which can contribute to the development of more effective vaccines

Lemierre Syndrome: A Case of Postanginal Sepsis

Lemierre syndrome is a rare disease that's characterized by internal jugular vein thrombosis and septic emboli. These symptoms typically develop after acute oropharyngeal infection by Fusobacterium necrophorum1). Although this syndrome is less frequently seen in modern times due to the availability of antibiotics, physicians must be aware of the syndrome in order to initiate prompt antibiotics therapy, including coverage of the anerobic organisms. We discuss here the case of an 18-year-old female with Lemierre syndrome and we review the relevant literature on this syndrome

Successful Radiofrequency Catheter Ablation for Wolff-Parkinson-White Syndrome Within the Neck of a Coronary Sinus Diverticulum

Posteroseptal accessory pathways are often associated with coronary sinus diverticula. These diverticula contain myocardial coats which serve as a bypass tract. We report a 54-year-old woman who underwent radiofrequency (RF) catheter ablation for Wolff-Parkinson-White (WPW) syndrome. The surface electrocardiography (ECG) demonstrated pre-excitation, indicating a posteroseptal accessory pathway. A catheter ablation via a transaortic approach failed to ablate the accessory pathway. Coronary sinus venography revealed the presence of a diverticulum near the ostium. An electrogram in the neck of the diverticulum showed the coronary sinus myocardial extension potential, which was successfully ablated by delivery of RF energy

Potential effectiveness of digital therapeutics specialized in executive functions as adjunctive treatment for clinical symptoms of attention-deficit/hyperactivity disorder: a feasibility study

IntroductionThe role of digital therapeutics (DTx) in the effective management of attention deficit/hyperactivity disorder (ADHD) is beginning to gain clinical attention. Therefore, it is essential to verify their potential efficacy.MethodWe aimed to investigate the improvement in the clinical symptoms of ADHD by using DTx AimDT01 (NUROW) (AIMMED Co., Ltd., Seoul, Korea) specialized in executive functions. NUROW, which consists of Go/No-go Task- and N-Back/Updating-based training modules and a personalized adaptive algorithm system that adjusts the difficulty level according to the user’s performance, was implemented on 30 Korean children with ADHD aged 6 to 12 years. The children were instructed to use the DTx for 15 min daily for 4 weeks. The Comprehensive attention test (CAT) and Childhood Behavior Checklist (CBCL) were used to assess the children at baseline and endpoint. In contrast, the ADHD-Rating Scale (ARS) and PsyToolkit were used weekly and followed up at 1 month, for any sustained effect. Repeated measures ANOVA was used to identify differences between the participants during visits, while t-tests and Wilcoxon signed-rank tests were used to identify changes before and after the DTx.ResultsWe included 27 participants with ADHD in this analysis. The ARS inattention (F = 4.080, p = 0.010), hyperactivity (F = 5.998. p < 0.001), and sum (F = 5.902, p < 0.001) significantly improved. After applying NUROW, internalized (t = −3.557, p = 0.001, 95% CI = −3.682-−0.985), other (Z = −3.434, p = 0.001, effect size = −0.661), and sum scores (t = −3.081, p = 0.005, 95% CI = −10.126-−2.022) were significantly changed in the CBCL. The overall effect was confirmed in the ARS sustained effect analysis even after 1 month of discontinuing the DTx intervention.DiscussionAccording to caregivers, the findings indicate that DTx holds potential effect as an adjunctive treatment in children with ADHD, especially in subjective clinical symptoms. Future studies will require detailed development and application targeting specific clinical domains using DTx with sufficient sample sizes.Clinical trial registration: KCT0007579

Ascorbic acid increases demethylation in somatic cell nuclear transfer embryos of the pig ()

Objective Investigated the effect and mechanism of ascorbic acid on the development of porcine embryos produced by somatic cell nuclear transfer (SCNT). Methods Porcine embryos were produced by SCNT and cultured in the presence or absence of ascorbic acid. Ten-eleven translocation 3 (TET3) in oocytes was knocked down by siRNA injection. After ascorbic acid treatment, reprogramming genes were analyzed by realtime reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, relative 5-methylcytosine and 5-hydroxymethylcytosine content in pronucleus were detected by realtime PCR. Results Ascorbic acid significantly increased the development of porcine embryos produced by SCNT. After SCNT, transcript levels of reprogramming genes, Pou5f1, Sox2, and Klf were significantly increased in blastocysts. Furthermore, ascorbic acid reduced 5-methylcytosine content in pronuclear embryos compared with the control group. Knock down of TET3 in porcine oocytes significantly prevents the demethylation of somatic cell nucleus after SCNT, even if in the presence of ascorbic acid. Conclusion Ascorbic acid enhanced the development of porcine SCNT embryos via the increased TET3 mediated demethylation of somatic nucleus

Machine learning-based evaluation of spontaneous pain and analgesics from cellular calcium signals in the mouse primary somatosensory cortex using explainable features

IntroductionPain that arises spontaneously is considered more clinically relevant than pain evoked by external stimuli. However, measuring spontaneous pain in animal models in preclinical studies is challenging due to methodological limitations. To address this issue, recently we developed a deep learning (DL) model to assess spontaneous pain using cellular calcium signals of the primary somatosensory cortex (S1) in awake head-fixed mice. However, DL operate like a “black box”, where their decision-making process is not transparent and is difficult to understand, which is especially evident when our DL model classifies different states of pain based on cellular calcium signals. In this study, we introduce a novel machine learning (ML) model that utilizes features that were manually extracted from S1 calcium signals, including the dynamic changes in calcium levels and the cell-to-cell activity correlations.MethodWe focused on observing neural activity patterns in the primary somatosensory cortex (S1) of mice using two-photon calcium imaging after injecting a calcium indicator (GCaMP6s) into the S1 cortex neurons. We extracted features related to the ratio of up and down-regulated cells in calcium activity and the correlation level of activity between cells as input data for the ML model. The ML model was validated using a Leave-One-Subject-Out Cross-Validation approach to distinguish between non-pain, pain, and drug-induced analgesic states.Results and discussionThe ML model was designed to classify data into three distinct categories: non-pain, pain, and drug-induced analgesic states. Its versatility was demonstrated by successfully classifying different states across various pain models, including inflammatory and neuropathic pain, as well as confirming its utility in identifying the analgesic effects of drugs like ketoprofen, morphine, and the efficacy of magnolin, a candidate analgesic compound. In conclusion, our ML model surpasses the limitations of previous DL approaches by leveraging manually extracted features. This not only clarifies the decision-making process of the ML model but also yields insights into neuronal activity patterns associated with pain, facilitating preclinical studies of analgesics with higher potential for clinical translation

Clinical Application of 7.0 T Magnetic Resonance Images in Gamma Knife Radiosurgery for a Patient with Brain Metastases

In the study we assessed the distortion of 7.0 T magnetic resonance (MR) images in reference to 1.5 T MR images in the radiosurgery of metastatic brain tumors. Radiosurgery with Gamma Knife Perfexion® was performed for the treatment of a 54-yr-old female patient with multiple brain metastases by the co-registered images of the 7.0 T and 1.5 T magnetic resonance images (MRI). There was no significant discrepancy in the positions of anterior and posterior commissures as well as the locations of four metastatic brain tumors in the co-registered images between 7.0 T and 1.5 T MRI with better visualization of the anatomical details in 7.0 T MR images. This study demonstrates for the first time that 7.0 T MR images can be safely utilized in Perfexion® Gamma Knife radiosurgery for the treatment of metastatic brain tumors. Furthermore 7.0 T MR images provide better visualization of brain tumors without image distortion in comparison to 1.5 T MR images