Impact of water on toxic hydrogen fluoride generation from the decomposition of LiPF6 in lithium-ion battery electrolytes

PresentationToxic hydrogen fluoride (HF) gas can be generated when LiPF6, a salt used in lithium-ion battery electrolytes, thermally decomposes and/or reacts with trace water. Simultaneous thermal analysis and mass spectrometry (STA-MS) was conducted on five different organic solvents containing LiPF6 to determine the temperatures at which HF is generated and the activation energies of the decomposition reaction. STA-MS allows the simultaneous direct observation of electrolyte thermal stability and hydrogen fluoride generation, something that is not possible with gas chromatography–mass spectrometry alone, thus it represents a more efficient and simple experimental approach. The five solvents tested in this study were anhydrous tetrahydrofurfuryl alcohol (THFA), 1,3- dioxolane (1,3-DL), diethyl carbonate (DEC), 1,2-dimethoxyethane (DME), and ethyl carbonate (EC). STA-MS analysis of the LiPF6 in these solvents revealed that HF generation occurred at different temperatures for each electrolyte. In the case of 1M LiPF6 in THFA, the addition of 1000 ppm of water reduced the thermal decomposition temperature compared to solid neat LiPF6. Except for EC, all of the other electrolyte systems exhibited a lower HF generation temperature and a lower reaction activation energy (Ea) when water was present. Additionally, from a risk assessment perspective, the results indicate that the HF generation starts from the SEI layer decomposition stage which occurs early in the thermal runaway mechanism of the lithium-ion battery. This research can be used to develop more thermally stable and safer electrolytes in the future, especially with respect to HF generation. In addition, this study highlights the need for research into measures to combat large-capacity lithium-ion battery fires, which may occur in electric vehicles and grid-scale energy storage systems

Synchronous double primary malignant tumor of the gallbladder and liver: a case report

We report a case of synchronous double primary tumor of gallbladder and liver. A 63-year-old male was admitted to the hospital complaining of abdominal discomfort. Enhanced computed tomography of the abdomen showed acute cholecystitis with tiny gallbladder stones and a 2.2 cm size enhanced nodule in the left lobe of the liver. Under the impression of acute cholecystitis with gall bladder stones and hepatocellular carcinoma of the left Liver, the patient underwent a laparotomy. At laparotomy, a mass was palpated on the surface of the neck portion of the gall bladder. Intraoperative frozen diagnosis revealed adenocarcinoma of the gall bladder. The patient was diagnosed as having gall bladder cancer and hepatocellular carcinoma, so extended cholecystectomy with dissection of regional lymph nodes and left hemihepatectomy were performed. Histological examination revealed moderated differentiated adenocarcinoma of gallbladder and hepatocellular carcinoma of liver. To our knowledge, the simultaneous occurrence of primary malignant tumor of the gallbladder and liver has never been published before. The patient is doing well with no evidence of recurrence 17 months after surgery

Experimental observation of hidden Berry curvature in inversion-symmetric bulk 2H-WSe2

We investigate the hidden Berry curvature in bulk 2H-WSe2 by utilizing the surface sensitivity of angle resolved photoemission (ARPES). The symmetry in the electronic structure of transition metal dichalcogenides is used to uniquely determine the local orbital angular momentum (OAM) contribution to the circular dichroism (CD) in ARPES. The extracted CD signals for the K and K' valleys are almost identical but their signs, which should be determined by the valley index, are opposite. In addition, the sign is found to be the same for the two spin-split bands, indicating that it is independent of spin state. These observed CD behaviors are what are expected from Berry curvature of a monolayer of WSe2. In order to see if CD-ARPES is indeed representative of hidden Berry curvature within a layer, we use tight binding analysis as well as density functional calculation to calculate the Berry curvature and local OAM of a monolayer WSe2. We find that measured CD-ARPES is approximately proportional to the calculated Berry curvature as well as local OAM, further supporting our interpretation.Comment: 6 pages, 3 figure

Correlation between Histological Activity and Endoscopic, Clinical, and Serologic Activities in Patients with Ulcerative Colitis

Objectives. Recent studies suggest that histological healing is a treatment goal in ulcerative colitis (UC). We aimed to evaluate the correlation between histological activity and clinical, endoscopic, and serologic activities in patients with UC. Methods. We retrospectively reviewed medical records from patients with UC who underwent colonoscopy or sigmoidoscopy with biopsies. The Mayo endoscopic subscore was used to assess endoscopic activity. Biopsy specimens were reviewed by two blinded pathologists and scored using the Geboes scoring system. Results. We analyzed 154 biopsy specimens from 82 patients with UC. Histological scores exhibited strong correlation with endoscopic subscores (Spearman’s rank correlation coefficient r=0.774, p<0.001) and moderate correlation with C-reactive protein levels (r=0.422, p<0.001) and partial Mayo scores (r=0.403, p<0.001). Active histological inflammation (Geboes score ≥ 3.1) was observed in 6% (2 of 33) of the endoscopically normal mucosa samples, 66% (19 of 29) of mild disease samples, and 98% (90 of 92) of moderate-to-severe disease samples. Conclusions. Histological activity was closely correlated with the endoscopic, clinical, and serologic UC activities. However, several patients with mild or normal endoscopic findings exhibited histological evidence of inflammation. Therefore, histological assessment may be helpful in evaluating treatment outcomes and determining follow-up strategies

Isolated vestibular nuclear infarction: report of two cases and review of the literature

Cerebral infarction presenting with isolated vertigo remains a diagnostic challenge. To define the clinical characteristics of unilateral infarctions restricted to the vestibular nuclei, two patients with isolated unilateral vestibular nuclear infarction had bedside and laboratory evaluation of the ocular motor and vestibular function, including video-oculography, bithermal caloric irrigation, the head impulse test (HIT) using magnetic scleral coils, and cervical and ocular vestibular-evoked myogenic potentials (VEMPs). We also reviewed the literature on isolated vertigo from lesions restricted to the vestibular nuclei, and analyzed the clinical features of seven additional patients. Both patients showed spontaneous torsional-horizontal nystagmus that beat away from the lesion side, and direction-changing gaze-evoked nystagmus. Recording of HIT using a magnetic search coil system documented decreased gains of the vestibular-ocular reflex for the horizontal and posterior semicircular canals on both sides, but more for the ipsilesional canals. Bithermal caloric tests showed ipsilesional canal paresis in both patients. Cervical and ocular VEMPs showed decreased or absent responses during stimulation of the ipsilesional ear. Initial MRIs including diffusion-weighted images were normal or equivocal, but follow-up imaging disclosed a circumscribed acute infarction in the area of the vestibular nuclei. Infarctions restricted to the vestibular nuclei may present with isolated vertigo with features of both peripheral and central vestibulopathies. Central signs should be sought even in patients with spontaneous horizontal-torsional nystagmus and positive HIT. In patients with combined peripheral and central vestibulopathy, a vestibular nuclear lesion should be considered especially when hearing is preserved.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000004487/4SEQ:4PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000004487ADJUST_YN:YEMP_ID:A075641DEPT_CD:801CITE_RATE:3.841FILENAME:kimhj-isolated vn inf-j neurol-2014-261(1)121.pdfDEPT_NM:의학과SCOPUS_YN:YCONFIRM:

Sulforaphane Increases Cyclin-Dependent Kinase Inhibitor, p21 Protein in Human Oral Carcinoma Cells and Nude Mouse Animal Model to Induce G2/M Cell Cycle Arrest

Previously, our group reported that sulforaphane (SFN), a naturally occurring chemopreventive agent from cruciferous vegetables, effectively inhibits the proliferation of KB and YD-10B human oral squamous carcinoma cells by causing apoptosis. In this study, treatment of 20 and 40 µM of SFN for 12 h caused a cell cycle arrest in the G2/M phase. Cell cycle arrest induced by SFN was associated with a significant increase in the p21 protein level and a decrease in cyclin B expression, but there was no change in the cyclin A protein level. In addition, SFN increased the p21 promoter activity significantly. Furthermore, SFN induced p21 protein expression in a nude mouse xenograft model suggesting that SFN is a potent inducer of the p21 protein in human oral squamous carcinoma cells. These findings show that SFN is a promising candidate for molecular-targeting chemotherapy against human oral squamous cell carcinoma

Experimental Study on Electromagnetic Forming of High Strength Steel Sheets with Different Dimensions of Aluminum Driver Plate

Recently, the potential of the electromagnetic forming process has been introduced to form the shallow longitudinal reinforcement ribs in the lateral walls of roll formed parts, made of high strength steel sheets of 340MPa tensile stress grade [1]. However, it seems that the application may not be easy for high strength steel sheet because of its high tensile strength and low electric conductivity. In order to overcome this difficulty, aluminum driver plate could be considered to enhance the formability of high strength steel sheets in the electromagnetic forming process. In this paper, in order to investigate the effect of aluminum driver plate on forming height of high strength steel sheet in electromagnetic forming process, DP780 workpiece sheets were formed into a hemi elliptical protrusion shape with Al1050 driver plate of various thicknesses and sizes. Experiments were performed with a flat spiral coil actuator connected to an electromagnetic forming system. The results, the aluminum driver plate helps to increase the forming height of high strength steel sheets. In addition, the forming height of high strength steel sheet increases as the thickness and size of a driver plate increases