Herein, the structure resulting from in situ turnover in a chemically challenging quaternary ammonium oxidative demethylation reaction was captured via crystallographic analysis and analyzed via ...single-crystal spectroscopy. Crystal structures were determined for the Rieske-type monooxygenase, stachydrine demethylase, in the unliganded state (at 1.6 Å resolution) and in the product complex (at 2.2 Å resolution). The ligand complex was obtained from enzyme aerobically cocrystallized with the substrate stachydrine (N,N-dimethylproline). The ligand electron density in the complex was interpreted as proline, generated within the active site at 100 K by the absorption of X-ray photon energy and two consecutive demethylation cycles. The oxidation state of the Rieske iron–sulfur cluster was characterized by UV–visible spectroscopy throughout X-ray data collection in conjunction with resonance Raman spectra collected before and after diffraction data. Shifts in the absorption band wavelength and intensity as a function of absorbed X-ray dose demonstrated that the Rieske center was reduced by solvated electrons generated by X-ray photons; the kinetics of the reduction process differed dramatically for the liganded complex compared to unliganded demethylase, which may correspond to the observed turnover in the crystal.
As the unparalleled ability of big data to capture and process real-time information signals a revolution in public administration, countries around the world have begun to explore the application of ...the technology to government functions. At the forefront of these efforts is China, which is planning to launch the social credit system (SCS), a data-powered project to monitor, assess, and shape the behavior of all citizens and enterprises. This new frontier of digital surveillance raises questions about how the United States will incorporate data technology into its own politics and economy. This article argues that the U.S. needs a comprehensive nationwide data protection framework that places limits on surveillance by both private business and the government. Without drawing its own baseline for personal data protection, the United States risks missing the already narrowing opportunity to define its balance between democracy, security, and growth.
To cope with data communication explosion, the alternative, "D2D communication" which enables mobile devices to communicate each other without base station is studied. D2D providing service at a ...lower cost than cellular network is advantageous for user and also helpful when infra system is out of order by natural disaster. Even if D2D communication has a lot of benefits, that the D2D communication interferes cellular links as well as D2D link each other should be managed. This paper proposes a radio resource allocation policy for D2D link. Firstly, in frequency domain, by introducing D2D belt concept (the area where users cannot user frequency available only for D2D link) orthogonality between cellular links and D2D links is guaranteed in frequency domain. Secondly, by allocating un-overlapping subframe to D2D links, the interferences between D2D links can be eliminated.
With the rapid development and multifarious application of artificial intelligence technology, elementary learners are demanded to learn about AI. At the same time, due to the pandemic, classes ...without face-to-face contact have been increasing. This study aims to develop teaching-learning contents instructing core principles of artificial intelligence, respectively in face-to-face and non-face-to-face learning environments. Proposed teaching-learning contents mainly target elementary learner and provide simplified experience for convolutional neural network(CNN) algorithm. Learners accomplish convolution operation with simple numbers then extract feature map. Students experience CNN process with 5x5 virtual input image consists of numbers. 2x2 filter is given for convolution operation, and students fill 4x4 feature map with the results. These same teaching-learning activities can be also offered with online interactive worksheets, using ‘LIVEWORKSHEETS’ website. By transforming printed worksheets into online ones, learners in distance learning classes can accomplish identical coursework clicking and typing then score themselves. Teachers and learners can choose appropriate teaching-learning way or mix both of them flexibly based on their situation. Subsequent studies are expected to revise the contents after sufficient pilot classes with diverse learner groups and devise additional physical teaching-learning activity suitable for elementary learners. This study proposes the importance of continuous research on artificial intelligence education for young learners and versatile teaching-learning contents for various learning environment.
X-ray free-electron lasers (XFELs) provide very intense X-ray pulses suitable for macromolecular crystallography. Each X-ray pulse typically lasts for tens of femtoseconds and the interval between ...pulses is many orders of magnitude longer. Here we describe two novel acoustic injection systems that use focused sound waves to eject picoliter to nanoliter crystal-containing droplets out of microplates and into the X-ray pulse from which diffraction data are collected. The on-demand droplet delivery is synchronized to the XFEL pulse scheme, resulting in X-ray pulses intersecting up to 88% of the droplets. We tested several types of samples in a range of crystallization conditions, wherein the overall crystal hit ratio (e.g., fraction of images with observable diffraction patterns) is a function of the microcrystal slurry concentration. We report crystal structures from lysozyme, thermolysin, and stachydrine demethylase (Stc2). Additional samples were screened to demonstrate that these methods can be applied to rare samples.
Display omitted
•Acoustic methods inject crystal-containing droplets directly from microplate wells•On-demand acoustic injection uses crystals efficiently without orifices or clogging•Diffraction patterns from crystals measuring several tens of μm are of high quality•Complete datasets can be obtained from fewer than 50,000 crystals
Acoustic droplet ejection provides an automated tool for efficient use of protein crystals in SFX experiments. Roessler et al. used this method to deliver crystal-containing droplets into the XFEL beam to coincide with each X-ray pulse.
Objective: We wanted to determine the optimal dose of intravenous penicillin (PCN) in the third trimester of pregnancy for the prophylaxis of group B Streptococcus. Study Design: Healthy women in the ...third trimester with a singleton pregnancy were recruited. Eligibility included no previous penicillin or cephalosporin allergy and no history of renal disease. We obtained a baseline 24-hour urine collection for total protein concentration and creatinine clearance. Two intravenous catheters were placed, and 1 million units of penicillin G (PCN G) sodium was infused through one catheter. Serial blood samples were obtained through the second catheter at 1, 5, 15, 30, 60, 90, 120, 150, 180, 210, and 240 minutes. Serum was stored at –80°C until assays were performed. Reverse-phase highperformance liquid chromatography was used to determine serum concentrations. Results: Fifteen patients met the requirements for eligibility. The average 24-hour urine sample for total protein concentration was 187 mg/dL (range, 11-252), and creatinine clearance was 191 mL/min (range, 137-245). Average maximum serum concentration (Cmax) was 67 μg/mL (range, 34-132) and was reached within 5 minutes. Average serum PCN concentration was 12 μg/mL (range, 9-25) after 4 hours of urine collection. Conclusion: The Cmax was 67 μg/mL (670 × minimum inhibitory concentration). One million units of intravenous PCN G exceeds MIC in the treatment of GBS. The dosing interval should be 4 hours to ensure anti-GBS activity in all patients. More frequent dosing does not increase activity. Current recommendations for GBS prophylaxis which use PCN G should be modified pending future studies of neonatal PCN concentrations. (Am J Obstet Gynecol 2001;185: 850-3.)
Six isocaloric diets containing 30, 40, 45, 50, 55 and 60% crude protein (CP) were fed to juvenile yellow puffer Takifugu obscurus to determine their optimum dietary level of protein. After a 12-week ...feeding trial, weight gain of fish fed 50% CP diet was not significantly different from that of fish fed 55% CP diet, but significantly higher (P<0.05) than that of fish fed 30, 40, 45 and 60% CP diet. Also, a broken-line model analysis for weight gain indicated that the optimum dietary protein level was 50 plus or minus 3.7% (mean plus or minus SD). Fish fed 50% CP also had the highest feed efficiency and hepatosomatic index. Condition factor increased with dietary protein level. No significant differences existed in haematocrit, hemoglobin and survival rate among the dietary treatments. Therefore, these findings suggest that the optimum protein level is approximately 50% of dry diet for maximum growth in juvenile yellow puffer.
X-ray free-electron lasers (XFELs) provide very intense X-ray pulses suitable for macromolecular crystallography. Each X-ray pulse typically lasts for tens of femtoseconds and the interval between ...pulses is many orders of magnitude longer. Here we describe two novel acoustic injection systems that use focused sound waves to eject picoliter to nanoliter crystal-containing droplets out of microplates and into the X-ray pulse from which diffraction data are collected. The on-demand droplet delivery is synchronized to the XFEL pulse scheme, resulting in X-ray pulses intersecting up to 88% of the droplets. We tested several types of samples in a range of crystallization conditions, wherein the overall crystal hit ratio (e.g., fraction of images with observable diffraction patterns) is a function of the microcrystal slurry concentration. Lastly, we report crystal structures from lysozyme, thermolysin, and stachydrine demethylase (Stc2). In addition, samples were screened to demonstrate that these methods can be applied to rare samples
PDF
