Dynamic Stability of a Rectangular Plate Subjected to In-plane Dynamic Shearing Force

Dynamic instability of a rectangular plate subjected to in-plane sinusoidally time-varying shearing force is analyzed. The small deflection theory of the thin plate is used. The problem is solved by using a Galerkin method and the harmonic balance method. After presenting the problem in the form of divided matrix equations, numerical results are presented first for natural frequencies of the loaded plate and second for dynamic unstable regions of the rectangular plate with various boundary conditions

Anti-prion activity of an RNA aptamer and its structural basis.

Prion proteins (PrPs) cause prion diseases, such as bovine spongiform encephalopathy. The conversion of a normal cellular form (PrP(C)) of PrP into an abnormal form (PrP(Sc)) is thought to be associated with the pathogenesis. An RNA aptamer that tightly binds to and stabilizes PrP(C) is expected to block this conversion and to thereby prevent prion diseases. Here, we show that an RNA aptamer comprising only 12 residues, r(GGAGGAGGAGGA) (R12), reduces the PrP(Sc) level in mouse neuronal cells persistently infected with the transmissible spongiform encephalopathy agent. Nuclear magnetic resonance analysis revealed that R12, folded into a unique quadruplex structure, forms a dimer and that each monomer simultaneously binds to two portions of the N-terminal half of PrP(C), resulting in tight binding. Electrostatic and stacking interactions contribute to the affinity of each portion. Our results demonstrate the therapeutic potential of an RNA aptamer as to prion diseases

Internet-Based Inquiries From Users With the Intention to Overdose With Over-the-Counter Drugs: Qualitative Analysis of Yahoo! Chiebukuro

市販薬乱用に関して投稿された質問の分析 --Yahoo!知恵袋内テキストデータの定性分析--. 京都大学プレスリリース. 2023-12-05.[Background:] Public concern with regard to over-the-counter (OTC) drug abuse is growing rapidly across countries. OTC drug abuse has serious effects on the mind and body, such as poisoning symptoms, and often requires specialized treatments. In contrast, there is concern about people who potentially abuse OTC drugs whose symptoms are not serious enough to consult medical institutions or drug addiction rehabilitation centers yet are at high risk of becoming drug dependent in the future. [Objective:] Consumer-generated media (CGM), which allows users to disseminate information, is being used by people who abuse (and those who are trying to abuse) OTC drugs to obtain information about OTC drug abuse. This study aims to analyze the content of CGM to explore the questions of people who potentially abuse OTC drugs. [Methods:] The subject of this research was Yahoo! Chiebukuro, the largest question and answer website in Japan. A search was performed using the names of drugs commonly used in OTC drug abuse and the keywords overdose and OD, and the number of questions posted on the content of OTC drug abuse was counted. Furthermore, a thematic analysis was conducted by extracting text data on the most abused antitussive and expectorant drug, BRON. [Results:] The number of questions about the content of overdose medications containing the keyword BRON has increased sharply as compared with other product names. Furthermore, 467 items of question data that met the eligibility criteria were obtained from 528 items of text data on BRON; 26 codes, 6 categories, and 3 themes were generated from the 578 questions contained in these items. Questions were asked about the effects they would gain from abusing OTC drugs and the information they needed to obtain the effects they sought, as well as about the effects of abuse on their bodies. Moreover, there were questions on how to stop abusing and what is needed when seeking help from a health care provider if they become dependent. It has become clear that people who abuse OTC drugs have difficulty in consulting face-to-face with others, and CGM is used as a means to obtain the necessary information anonymously. [Conclusions:] On CGM, people who abused or tried to abuse OTC drugs were asking questions about their abuse expectations and anxieties. In addition, when they became dependent, they sought advice to quit their abuse. CGM was used to exchange information about OTC drug abuse, and many questions on anxieties and hesitations were posted. This study suggests that it is necessary to produce and disseminate information on OTC drug abuse, considering the situation of those who abuse or are willing to abuse OTC drugs. Support from pharmacies and drugstores would also be essential to reduce opportunities for OTC drug abuse

Structural basis for recognition of cognate tRNA by tyrosyl-tRNA synthetase from three kingdoms

The specific aminoacylation of tRNA by tyrosyl-tRNA synthetases (TyrRSs) relies on the identity determinants in the cognate tRNATyrs. We have determined the crystal structure of Saccharomyces cerevisiae TyrRS (SceTyrRS) complexed with a Tyr-AMP analog and the native tRNATyr(GΨA). Structural information for TyrRS–tRNATyr complexes is now full-line for three kingdoms. Because the archaeal/eukaryotic TyrRSs–tRNATyrs pairs do not cross-react with their bacterial counterparts, the recognition modes of the identity determinants by the archaeal/eukaryotic TyrRSs were expected to be similar to each other but different from that by the bacterial TyrRSs. Interestingly, however, the tRNATyr recognition modes of SceTyrRS have both similarities and differences compared with those in the archaeal TyrRS: the recognition of the C1-G72 base pair by SceTyrRS is similar to that by the archaeal TyrRS, whereas the recognition of the A73 by SceTyrRS is different from that by the archaeal TyrRS but similar to that by the bacterial TyrRS. Thus, the lack of cross-reactivity between archaeal/eukaryotic and bacterial TyrRS-tRNATyr pairs most probably lies in the different sequence of the last base pair of the acceptor stem (C1-G72 vs G1-C72) of tRNATyr. On the other hand, the recognition mode of Tyr-AMP is conserved among the TyrRSs from the three kingdoms

Synchronous neuroendocrine tumors in both the pancreas and ileum: A case report

AbstractIntroductionAlthough it is well-known that in multiple endocrine neoplasia type 1 (MEN 1) disease, multiple endocrine lesions frequently occur, synchronous or metachronous neuroendocrine tumors (NETs) in non-MEN 1 patients are extremely rare.Presentation of caseAn asymptomatic 72-year-old woman with an ileal NET was referred to our hospital. Abdominal computed tomography revealed another circular tumor within the pancreatic head. She was classified as a non-MEN 1 patient. An operative procedure was performed with a preoperative diagnosis of synchronous NET, which was confirmed by pathological examination.DiscussionBoth morphologic and immunophenotypic findings were different between in the ileum and pancreas. Therefore, it was reasonable to consider that both tumors were primary tumors. The synchronous occurrence of these tumors is unusual, and it may be considered as a chance occurrence.ConclusionWe here report the first case of synchronous pancreatic NET and ileal NET in a non-MEN 1 patient

Antitumor effects of inductive hyperthermia using magnetic ferucarbotran nanoparticles on human lung cancer xenografts in nude mice

Background: The effects of inductive hyperthermia on lung cancer have yet to be fully investigated. Magnetic nanoparticles used in inductive hyperthermia are made-to-order and expensive. This study was performed to investigate the use of ferucarbotran in inductive hyperthermia and to clarify whether inductive hyperthermia using ferucarbotran promotes antitumor effects in vivo using a lung cancer cell line. Methods: We injected A549 cells subcutaneously into the right thighs of BALB/c nu/nu nude mice. Forty mice with A549 xenografts were then classified into three groups. Group 1 was the control group. All mice in groups 2 and 3 had ferucarbotran injected into their tumors, and mice in group 3 were then subjected to alternating magnetic field irradiation. We evaluated tumor temperature during the hyperthermic procedure, the time course of tumor growth, histologic findings in tumors after hyperthermic treatment, and adverse events. Results: Intratumor temperature rose rapidly and was maintained at 43°C-45°C for 20 minutes in an alternating magnetic field. Tumor volumes in groups 1 and 2 increased exponentially, but tumor growth in group 3 was significantly suppressed. No severe adverse events were observed. Histologic findings for the tumors in group 3 revealed mainly necrosis. Conclusion: Inductive hyperthermia using ferucarbotran is a beneficial and promising approach in the treatment of lung cancer. Ferucarbotran is a novel tool for further development of inductive hyperthermia. © 2013 Araya et al, publisher and licensee Dove Medical Press Ltd