Finite element modeling of a textured seal design for reduced wear

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.Includes bibliographical references (p. 173-175).by Oscar C.H. Yeh.M.S

Different Renal Function Equations and Dosing of Direct Oral Anticoagulants in Atrial Fibrillation

BACKGROUND: Randomized trials of direct oral anticoagulants (DOACs) adopted the Cockcroft-Gault (CG) formula to calculate estimated glomerular filtration rate (eGFR) to determine the dosages of DOACs. OBJECTIVES: The authors aimed to investigate the agreements/disagreements of eGFRs calculated using different equations (CG, Modified Diet in Renal Disease [MDRD], and Chronic Kidney Disease Epidemiology Collaboration [CKD-EPI] formulas), and their impacts on the dosages of DOACs and clinical outcomes. METHODS: Medical data from a multicenter health care provider in Taiwan including 39,239 patients with atrial fibrillation were used. Among these patients, there were 11,185 and 2,323 patients treated with DOACs and warfarin, respectively. RESULTS: At the cutoff values of eGFR of 50 mL/min, the agreements were 78% between MDRD and CG and 81% between CKD-EPI and CG. The disagreements among the different equations were largely due to overestimations, especially for patients aged >75 years and with a body weight of <50 kg (58.8% for MDRD and 50.9% for CKD-EPI). Among patients receiving DOACs whose dosages were defined as “on label” based on MDRD or CKD-EPI, only those whose dosages were “truly on label” based on CG were associated with a lower risk of major bleeding (adjusted HR: 0.34; 95% CI: 0.26-0.45) compared to warfarin. CONCLUSIONS: The adoptions of MDRD or CKD-EPI rather than CG would result in inappropriate dosing of DOACs (mainly overdosing), which would attenuate the advantages of DOACs compared to warfarin. The CG equation should be used as the gold standard to calculate eGFRs and guide the DOAC dosages

Learning Fine-Grained Visual Understanding for Video Question Answering via Decoupling Spatial-Temporal Modeling

While recent large-scale video-language pre-training made great progress in video question answering, the design of spatial modeling of video-language models is less fine-grained than that of image-language models; existing practices of temporal modeling also suffer from weak and noisy alignment between modalities. To learn fine-grained visual understanding, we decouple spatial-temporal modeling and propose a hybrid pipeline, Decoupled Spatial-Temporal Encoders, integrating an image- and a video-language encoder. The former encodes spatial semantics from larger but sparsely sampled frames independently of time, while the latter models temporal dynamics at lower spatial but higher temporal resolution. To help the video-language model learn temporal relations for video QA, we propose a novel pre-training objective, Temporal Referring Modeling, which requires the model to identify temporal positions of events in video sequences. Extensive experiments demonstrate that our model outperforms previous work pre-trained on orders of magnitude larger datasets.Comment: BMVC 2022. Code is available at https://github.com/shinying/des

Tectonic Implication of the 5th March 2005, Doublet Earthquake in Ilan, Taiwan

The 5th March 2005 earthquake doublet focal mechanism was determined as strike-slip faulting from Harvard and BATS moment tensor inversion. However, based on first motion polarities, the first shock has a normal focal mechanism (Wu et al. 2008a). This discrepancy has caused a debate over the focal mechanism solution because different focal mechanisms have different tectonic implications. Based on the dislocation determination from Global Position System (GPS) measurements, we find this event includes both tensile and strike-slip components. This finding illustrates the reason for the differences in the determined focal mechanisms using two different types of seismic data and analyzing methods. Field mapping and microstructure examination results indicate that the ductile deformation around the study area was characterized by the evolution from transpression to transtension with a predominant strike-slip component, but present-day active structures may be dominated by normal faulting. Thus, the active tensile slip result determined from dislocation modeling strongly suggests that the back arc extension of the Okinawa trough influences the stress state in this region, and changes the major transtension from strike-slip faulting to normal faulting

Screening and isolating eastern redcedar phytochemicals for creating economic opportunities in Missouri [abstract]

Eastern Redcedar (ERC) is one of the most widely distributed tree species in Missouri. The ERC is an important source of bioactive secondary metabolites, but very few of these biologically active compounds have been identified, purified or commercialized. An interdisciplinary collaboration between MU scientists was initiated in 2007 to identify and isolate biologically active phytochemicals from ERC tissues for possible commercial application. Our team has identified and purified biologically active compounds from leaves (needles) and fruit of the ERC. Many of these isolated diterpenoids not only have shown strong anti-microbial activities against a wide range of pathogenic bacteria, but also strong inhibitory activities against melanin biosynthesis. Recently, the isolated tricyclic diterpenoids have been recognized as promising anti-inflammatory, anti-microbial, and skin whitening agents by cosmetic and pharmaceutical industries. The objectives of the proposed study are to: 1) isolate and characterize the biologically active phytochemicals, and 2) elucidate chemical structures of active compounds and their associated mode of actions. The first of these compounds to be characterized is the purified bioactive diterpenoid. The purified bioactive diterpenoid was found to have a significant inhibitory effect on the growth of all Gram positive pathogens tested. This inhibition of Gram positive bacteria is likely due to action on the cell division machinery, for affected cells elongate without proper separation. Additional compounds have activity on fungal agents, as well as potential anti-melanin activities. The knowledge generated from our research will provide the opportunities to turn abundant, low-value, renewable materials from the ERC into a lucrative, high technology industry in Missouri. INVENTOR(S): Chun-Ho Lin; Brian M. Thompson; Hsin-Yeh Hsieh; Robert J. Kremer; Robert N. Lerch; Michael A. Gold and Harold E. Garrett CONTACT INFO: Harriet F. Francis, MS; J.D.; [email protected]; 573.884.0374 Per Stromhaug, Ph.D., MBA; [email protected]; 573.884.355

Conformational surveillance of Orai1 by a rhomboid intramembrane protease prevents inappropriate CRAC channel activation

Calcium influx through plasma membrane calcium release-activated calcium (CRAC) channels, which are formed of hexamers of Orai1, is a potent trigger for many important biological processes, most notably in T cell-mediated immunity. Through a bioinformatics-led cell biological screen, we have identified Orai1 as a substrate for the rhomboid intramembrane protease RHBDL2. We show that RHBDL2 prevents stochastic calcium signaling in unstimulated cells through conformational surveillance and cleavage of inappropriately activated Orai1. A conserved disease-linked proline residue is responsible for RHBDL2’s recognizing the active conformation of Orai1, which is required to sharpen switch-like signaling triggered by store-operated calcium entry. Loss of RHBDL2 control of CRAC channel activity causes severe dysregulation of downstream CRAC channel effectors, including transcription factor activation, inflammatory cytokine expression, and T cell activation. We propose that this surveillance function may represent an ancient activity of rhomboid proteases in degrading unwanted signaling proteins

Second-Hand Smoke–Induced Cardiac Fibrosis Is Related to the Fas Death Receptor Apoptotic Pathway without Mitochondria-Dependent Pathway Involvement in Rats

Exposure to environmental tobacco smoke has been epidemiologically linked to heart disease among nonsmokers. However, the molecular mechanism behind the pathogenesis of cardiac disease is unknown. In this study, we found that Wistar rats, exposed to tobacco cigarette smoke at doses of 5, 10, or 15 cigarettes for 30 min twice a day for 1 month, had a dose-dependently reduced heart weight to body weight ratio and enhanced interstitial fibrosis as identified by histopathologic analysis. The mRNA and activity of matrix metalloprotease-2 (MMP-2), representing the progress of cardiac remodeling, were also elevated in the heart. In addition, we used reverse-transcriptase polymerase chain reaction and Western blotting to demonstrate significantly increased levels of the apoptotic effecter caspase-3 in treated animal hearts. Dose-dependently elevated mRNA and protein levels of Fas, and promoted apoptotic initiator caspase-8 (active form), a molecule of a death-receptor–dependent pathway, coupled with unaltered or decreased levels of cytosolic cytochrome c and the apoptotic initiator caspase-9 (active form), molecules of mitochondria-dependent pathways, may be indicative of cardiac apoptosis, which is Fas death-receptor apoptotic-signaling dependent, but not mitochondria pathway dependent in rats exposed to second-hand smoke (SHS). With regard to the regulation of survival pathway, using dot blotting, we found cardiac insulin-like growth factor-1 (IGF-1) and IGF-1 receptor mRNA levels to be significantly increased, indicating that compensative effects of IGF-1 survival signaling could occur. In conclusion, we found that the effects of SHS on cardiomyocyte are mediated by the Fas death-receptor–dependent apoptotic pathway and might be related to the epidemiologic incidence of cardiac disease of SHS-exposed non-smokers

Triboelectrification-Enabled Self-Powered Detection and Removal of Heavy Metal Ions in Wastewater

route that works in a self-powered manner by harnessing the ambient energy using the triboelectrification effect. Relying on modified anodic aluminum oxide (AAO) a nanoporous surface with a layer of appropriate ligand molecules, serving as recognition element, the as-developed tribo-nanosensors can selectively capture and detect Cu 2+ , Pb 2+ , and Cr 3+ , which are commonly existing toxic heavy metal ions in industrial wastewater, in a sensing range of 0-200 × 10 −6 m with a sensitivity of 0.005 × 10 −6 , 0.003 × 10 −6 , and 0.004 × 10 −6 m −1 , respectively. The presented tribo-nanosensors are also proved to possess good stability after continuous working for up to 50,000 cycles. Moreover, the ambient triboelectrification effect was further utilized to develop a water-driven triboelectric nanogenerator (WD-TENG) as a sustainable power source for heavy metal ion removal by recycling the kinetic energy from flowing wastewater. The self-provided electric field can boost the migration and combination of ions as well as the electrolysis effect. The later induced a generation of large amount of OH − at the cathode in the wastewater, which promoted the precipitation of heavy metal ions. By controlling the wastewater pH values, Cu 2+ , Pb 2+ , and Cr 3+ were demonstrated to be fractionally precipitated from the wastewater. Under a fixed water flow rate of 3 L min −1 and initial heavy metal ion concentration of 100 × 10 −6 m, the self-powered cleaning system was capable of removing 97.4% of the heavy metal ions in the wastewater in 100 min. In addition, a further step was taken to recycle and collect the precipitated metals. Through a filtration, acidification, and chemical reduction process, pure metals are respectively obtained, which realizes the clean production and recycling economy. Featured as high detection sensitivity and removal efficiency, cost-effectiveness, simplicity as well as stability, the reported work not only opens a new and innovative pathway to environmentally friendly treatment of the ambient heavy metal ions, but also promotes substantial advancements in the fields of clinical toxicology, immunological surveillance, environmental monitoring, industrial waste management, and recycling economy. The triboelectrification enabled self-powered heavy metal ion treatment systematically consists of two steps, a tribonanosensor for metal ion detection and a water-driven triboelectric nanogenerator for metal ion removal. As demonstrated i