Yeast impact homolog 1 (Yih1), or IMPACT in mammals, is part of a conserved regulatory module controlling the activity of General Control Nonderepressible 2 (Gcn2), a protein kinase that regulates ...protein synthesis. Yih1/IMPACT is implicated not only in many essential cellular processes, such as neuronal development, immune system regulation and the cell cycle, but also in cancer. Gcn2 must bind to Gcn1 in order to impair the initiation of protein translation. Yih1 hinders this key Gcn1‐Gcn2 interaction by binding to Gcn1, thus preventing Gcn2‐mediated inhibition of protein synthesis. Here, we solved the structures of the two domains of Saccharomyces cerevisiae Yih1 separately using Nuclear Magnetic Resonance and determined the relative positions of the two domains using a range of biophysical methods. Our findings support a compact structural model of Yih1 in which the residues required for Gcn1 binding are buried in the interface. This model strongly implies that Yih1 undergoes a large conformational rearrangement from a latent closed state to a primed open state to bind Gcn1. Our study provides structural insight into the interactions of Yih1 with partner molecules.
Polyimides (PIs) have attracted wide attention because of their exceptional thermal stability and applications in areas such as printed circuit boards and multichip modules. It remains a great ...challenge, however, to control the morphologies and properties of PI‐based nanomaterials, especially porous PI‐based nanotubes. In this work, a versatile method to fabricate porous PI nanotubes via the template method is developed, with a solvent vapor–induced transformation process. First, polyamic acid (PAA) solutions are used as precursors and infiltrated into the nanochannels of anodic aluminum oxide templates, forming PAA nanotubes. After the samples are annealed in tetrahydrofuran or dimethylformamide vapors, depression of the PAA tubes occurs, causing the formation of pores. The porous PAA nanotubes can be further converted to porous PI and carbon nanotubes by imidization and carbonization processes, respectively. The pore sizes of the porous nanomaterials can be controlled by changing the type of the annealing solvent and the solvent annealing time.
A versatile method to fabricate porous polyimide (PI) nanotubes via the template method is presented. Polyamic acid (PAA) solutions are infiltrated into the nanochannels of anodic aluminum oxide templates, forming PAA nanotubes. After the solvent annealing process, porous PAA nanotubes are formed, which are further converted to porous PI and carbon nanotubes by imidization and carbonization processes, respectively.
An environmentally friendly method using real or artificial bovine milk permeate to both depilate and preserve sheepskins has been reported which completely and cleanly removed the wool from the hair ...follicle and had no detrimental effects on the skin. A proteomic analysis, assessing the relative abundance of proteins in matched permeate-depilated and chemically depilated (sulfide) sheepskins, showed variations in the levels of specific collagen types in the skin's basement membrane and other proteins associated with the follicles. These findings were corroborated by biochemical analyses of matched permeate depilated and raw skin samples, and provide clues to the mechanism of non-invasive and complete depilation. They also support the observation that permeate-depilated skins were smoother than their sulfide-depilated counterparts and resulted in leather with a superior surface.
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Block copolymers have attracted great attention because of their abilities to self-assemble into well-ordered microphase-separated structures. To generate nanopatterns of block copolymers with ...long-range ordering and low-defect densities in shorter time scales, microwave annealing has recently been applied. Microwave annealing, however, has so far only been used for block copolymer bulks and thin films. In this work, we discover that microwave annealing can be successfully applied to three-dimensional block copolymer nanostructures by studying the infiltration and microphase separation of block copolymers in cylindrical nanopores upon microwave irradiation. Cylinder-forming and lamella-forming poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) are introduced into the nanopores of anodic aluminum oxide (AAO) templates. In addition, AAO templates with different pore sizes are used to study the effect of the commensurabilities between the pore diameters and the repeating periods of the block copolymers on the morphologies of the block copolymer nanostructures.
The applications of Inertial Measurement Unit (IMU) based on Micro Electro Mechanical System (MEMS) are widely used because of its low-cost, small volume and low energy consumption. Unlike the ...accelerometers and magnetometers, which are respectively sensitive to vibrations and ferrous materials interference, MEMS type gyroscope is able to provide stable orientation information for a short period of time. Compared with these two sensors, gyroscopes are neither disturbed by vibrations nor affected by metallic materials, and therefore it would be one of the primary sensors for industrial applications. Reviewing the most recently related works, accurate attitude estimations are usually obtained by fusing gyro integration. However, it is well known that series drifts will be induced after a long-term integration. Furthermore, according to the literature and the associated experiments, they all demonstrated that MEMS type gyroscopes have strong temperature correlation because of the silicon structure. Put it simply, the temperature variations will give rise to gyro drifts severely and thereby degrade the orientation estimation precision. To address this problem, this article proposed a temperature modeling technique and a real-time drift pre-compensation procedure by applying autoregressive moving average (ARMA) technology. Different from the traditional modeling methods, the proposed method is able to describe transient drifting behaviors as well as steady state ones. Moreover, comparison studies using artificial neural networks (ANNs) are also presented. Experiments show that the proposed method provides a stable and reliable temperature-caused gyroscope drift pre-compensation. The developed method is also very suitable for the realization in a low-cost embedded system.
Polyimides (PIs) possess excellent mechanical properties, thermal stability, and chemical resistance and can be converted to carbon materials by thermal carbonization. The preparation of carbon ...nanomaterials by carbonizing PI‐based nanomaterials, however, has been less studied. In this work, the fabrication of PI nanofibers is investigated using electrospinning and their transformation to carbon nanofibers. Poly(amic acid) carboxylate salts (PAASs) solutions are first electrospun to form PAAS nanofibers. After the imidization and carbonization processes, PI and carbon nanofibers can then be obtained, respectively. The Raman spectra reveal that the carbon nanofibers are partially graphitized by the carbonization process. The diameters of the PI nanofibers are observed to be smaller than those of the PAAS nanofibers because of the formation of the more densely packed structures after the imidization processes; the diameters of the carbon nanofibers remain similar to those of the PI nanofibers after the carbonization process. The thermal dissipation behaviors of the PI and carbon nanofibers are also examined. The infrared images indicate that the transfer rates of thermal energy for the carbon nanofibers are higher than those for the PI nanofibers, due to the better thermal conductivity of carbon caused by the covalent sp2 bonding between carbon atoms.
The fabrication of polyimide (PI) nanofibers is investigated using electrospinning and their transformation to carbon nanofibers. The thermal dissipation behaviors of the PI and carbon nanofibers are also examined. The infrared images indicate that the transfer rates of thermal energy for the carbon nanofibers are higher than those for the PI nanofibers, due to the better thermal conductivity of carbon.
Template wetting methods have been broadly applied to fabricate diverse one-dimensional polymer nanomaterials. The currently used template wetting methods, however, have shortcomings and ...disadvantages such as long processing times, thermal degradation, and difficulties in controlling the lengths. In this work, we develop a novel microwave-annealing-induced nanowetting (MAIN) method to fabricate one-dimensional polymer nanomaterials using porous anodic aluminum oxide (AAO) templates. Upon microwave annealing, the polymer chains are infiltrated into the nanopores of the AAO templates, and the morphologies of the polymer nanomaterials can be controlled by the annealing conditions. The growth rates of the polymer nanomaterials using the MAIN method are faster than those using the traditional thermal annealing method. This work not only provides a time-saving method to fabricate one-dimensional polymer nanomaterials with controlled morphologies, but also offers a better understanding of the effect of microwave annealing on the wetting behaviors of polymer melts.
Influenza is a major cause of acute respiratory infection burden worldwide, leading to many hospitalizations. An annual influenza vaccine is believed to be the best way to prevent influenza-related ...illnesses. We focused on the efficacies of other possible preventive measures such as increasing sun exposure time and dietary supplements to prevent these illnesses.
We conducted a matched-pair case–control study along with the Taiwan Pediatric Infectious Disease Alliance. We included influenza-related hospitalized patients with age ranging from 6 months to 5 years during the 2012–2013, 2013–2014, 2014–2015, and 2015–2016 influenza seasons. The controls were comparable to cases in age, sex, and residential area and had no influenza-related hospitalization records in the same season. We extracted data from vaccination histories and got the patients’ guardians to complete questionnaires. Data were analyzed using conditional logistic regression.
We enrolled 1514 children (421 influenza-infected cases and 1093 controls) in the study. We found seasonal influenza vaccination to be an independent protective factor against hospitalizations owing to influenza p < 0.01; odds ratio (OR), 0.427; 95% confidence interval (CI), 0.306–0.594. Children with mean sun exposure time of >7 h/week had a significantly lower risk of influenza-related hospitalizations than those with the mean sun exposure time of ≤7 h/week (p < 0.05; OR, 0.667; 95% CI, 0.491–0.906).
Seasonal influenza vaccination effectively prevents influenza-related hospitalizations in children aged ≤5 years. Besides, >7 h of sun exposure/week may also be associated with lower risk of influenza-related hospitalizations in children.
This study aimed to compare the safety and efficacy of clarithromycin-naproxen-oseltamivir combination therapy to that of oseltamivir therapy alone in hospitalized pediatric influenza patients.
This ...prospective, single-blind study included children aged 1–18 years hospitalized with influenza, in MacKay Children's Hospital, Taiwan, between December 2017 and December 2019. The primary outcomes were the time to defervescence and decrease of the Pediatric Respiratory Severity Score (PRESS) during hospitalization. The secondary outcomes were serial changes in virus titers, measured using real-time polymerase chain reaction.
Fifty-four patients were enrolled (28 in the control group and 26 in the combination group) in total. There were no differences in the patients’ baseline characteristics between the groups. The time to defervescence was significantly shorter in the combination group than the oseltamivir group (13.2 h vs. 32.1 h, p = 0.002). The decrease in the virus titer from days 1–3 (log Δ13) was more pronounced in the combination group than the oseltamivir group. (39% vs. 19%, p = 0.001). There were no differences in adverse effects such as vomiting, diarrhea, and abdominal pain during the study or within 30 days after antiviral therapy.
The clarithromycin-naproxen-oseltamivir combination group experienced a more rapid defervescence and a more rapid decline of influenza virus titer than the group treated with oseltamivir alone. Further consideration should be given to whether the overall benefits of combination therapy in hospitalized pediatric influenza patients outweigh the risks.
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