27 research outputs found
Production of Recombinant Human DNA Polymerase Delta in a Bombyx mori Bioreactor
Eukaryotic DNA polymerase δ (pol δ) plays a crucial role in chromosomal DNA replication and various DNA repair processes. It is thought to consist of p125, p66 (p68), p50 and p12 subunits. However, rigorous isolation of mammalian pol δ from natural sources has usually yielded two-subunit preparations containing only p125 and p50 polypeptides. While recombinant pol δ isolated from infected insect cells have some problems of consistency in the quality of the preparations, and the yields are much lower. To address these deficiencies, we have constructed recombinant BmNPV baculoviruses using MultiBac system. This method makes the generation of recombinant forms of pol δ containing mutations in any one of the subunits or combinations thereof extremely facile. From about 350 infected larvae, we obtained as much as 4 mg of pol δ four-subunit complex. Highly purified enzyme behaved like the one of native form by rigorous characterization and comparison of its activities on poly(dA)/oligo(dT) template-primer and singly primed M13 DNA, and its homogeneity on FPLC gel filtration. In vitro base excision repair (BER) assays showed that pol δ plays a significant role in uracil-intiated BER and is more likely to mediate LP BER, while the trimer lacking p12 is more likely to mediate SN BER. It seems likely that loss of p12 modulates the rate of SN BER and LP BER during the repair process. Thus, this work provides a simple, fast, reliable and economic way for the large-scale production of human DNA polymerase δ with a high activity and purity, setting up a new platform for our further research on the biochemical properties of pol δ, its regulation and the integration of its functions, and how alterations in pol δ function could contribute to the etiology of human cancer or other diseases that can result from loss of genomic stability
The Integrative Effects of Leading by Example and Follower Traits in Public Goods Game: A Multilevel Study
As an important way to understand leadership based on voluntary contribution mechanisms, the importance of leading by example to teamwork is becoming more and more evident in recent years. However, existing theories based on signaling and reciprocity perspectives, respectively, provide incomplete theoretical explaining. This study adds clarity by conducting a cross-level study that indicates a possible integrative framework of both signaling and reciprocity perspective on leading by example. Results were using data gathered from 130 Chinese college students, which were allocated into one baseline group and three experimental groups. A hierarchical model was used to examine the effects of leading by example on different levels. It is found that leading by example has positive effects on the cooperation of followers on both the group level and the individual level. Risk attitudes have positive effects on the cooperation of followers while trust attitudes have negative effects. Our findings suggest that both leading by example and personal traits significantly influence cooperation but on different levels. It also reminds us that a more systematic way to understand leadership is needed
OPTICAL AND ELECTRICAL PROPERTIES OF La2O3 FILMS PREPARED BY ION BEAM ASSISTANT ELECTRON BEAM EVAPORATION
La2O3 films were deposited on Si(100) substrates by ion beam assistant electron beam evaporation and were annealed at 450–900°C. Crystalline structure was found to change from amorphous structure to cubic and hexagonal structure with the rise in annealing temperature. The near infrared transmittance of the film annealed at 600°C was relatively high and could be further increased using assistant ion beam in deposition. The maximum leakage current density increased dramatically from 10-7 to 10-4 A/cm2 with the rise in annealing temperature. The film annealed at 600°C with cubic structure had a relatively high dielectric constant of ~18.La2O3 films, electron beam evaporation, film structure, optical and electrical properties
Corporate Social Responsibility and Employee Outcomes: A Moderated Mediation Model of Organizational Identification and Moral Identity
Corporate social responsibility (CSR) research is not new, but its importance to today’s socially conscious market environment is even more evident in recent years. This study moves beyond CSR as simply the socially responsible actions and policies of organizations and focuses on the complex psychology of CSR as it relates to individuals within the organization. Given CSR can positively affect both the individuals within the organization and the organization itself, better understanding and leveraging the mechanisms and conditions of CSR that facilitate desired employee outcomes is crucial for organizational performance. However, scholars lack consensus in determining a theoretical framework for understanding how and under what conditions CSR will make an impact on employees and ultimately organizational performance. This study adds clarity by exploring the effect of perceived CSR on a more comprehensive set of employees’ attitudinal and behavioral reactions (i.e., turnover intention, in-role job performance, and helping behavior) via the mediating mechanism of organizational identification and the moderating condition of moral identity. Hypotheses were derived using social identity theory. Results were based on data obtained from 340 Chinese manufacturing employee-supervisor dyads. This study found that employees’ perceived CSR had an indirect relationship via organizational identification with each of the variables: (1) turnover intention, (2) in-role job performance, and (3) helping behavior. Specifically, the negative relationship between perceived CSR and turnover intention was stronger when employees had higher moral identity and the positive relationship between perceived CSR and in-role job performance and helping behavior was amplified by moral identity. Our findings show how the mediating mechanism of organizational identity and the moderating condition of moral identity work together to improve organizational effectiveness. The findings reveal several ways in which organizations can strategically focus their CSR and human resource efforts, such as applying this model and focusing on moral identity as a key indicator when evaluating employees
EFFECTS OF THERMAL EXPANSION COEFFICIENT MISMATCH ON STRUCTURE AND ELECTRICAL PROPERTIES OF TiO2 FILM DEPOSITED ON Si SUBSTRATE
Effects of thermal expansion coefficient (CTE) mismatch on structure and electrical properties of TiO2 film deposited on Si substrate by ion beam assistant electron beam evaporation have been investigated. Because of a high CTE mismatch between TiO2 film and Si substrate, microcracks appeared in the TiO2 film deposited directly on Si substrate after the as-deposited film was annealed at 600°C. In order to decrease the CTE mismatch, TiO2 film was deposited on Si substrate which was covered by a ZrO2 thin layer. As a result, crack–free TiO2 film after annealed at the same temperature was obtained. Meanwhile, corresponding to the crack–free structure, the TiO2 thin film has more stable dielectric properties and excellent I–V characteristics.Thin film, deposition, thermal expansion coefficient mismatch, microcracks, electrical properties
A Novel Multi-Task Learning Model with PSAE Network for Simultaneous Estimation of Surface Quality and Tool Wear in Milling of Nickel-Based Superalloy Haynes 230
For data-driven intelligent manufacturing, many important in-process parameters should be estimated simultaneously to control the machining precision of the parts. However, as two of the most important in-process parameters, there is a lack of multi-task learning (MTL) model for simultaneous estimation of surface roughness and tool wear. To address the problem, a new MTL model with shared layers and two task-specific layers was proposed. A novel parallel-stacked auto-encoder (PSAE) network based on stacked denoising auto-encoder (SDAE) and stacked contractive auto-encoder (SCAE) was designed as the shared layers to learn deep features from cutting force signals. To enhance the performance of the MTL model, the scaled exponential linear unit (SELU) was introduced as the activation function of SDAE. Moreover, a dynamic weight averaging (DWA) strategy was implemented to dynamically adjust the learning rate of different tasks. Then, the time-domain features were extracted from raw cutting signals and low-frequency reconstructed wavelet packet coefficients. Frequency-domain features were extracted from the power spectrum obtained by the Fourier transform. After that, all features were combined as the input vectors of the proposed MTL model. Finally, surface roughness and tool wear were simultaneously predicted by the trained MTL model. To verify the superiority and effectiveness of the proposed MTL model, nickel-based superalloy Haynes 230 was machined under different cutting parameter combinations and tool wear levels. Some other intelligent algorithms were also implemented to predict surface roughness and tool wear. The results showed that compared with the support vector regression (SVR), kernel extreme learning machine (KELM), MTL with SDAE (MTL_SDAE), MTL with SCAE (MTL_SCAE), and single-task learning with PSAE (STL_PSAE), the estimation accuracy of surface roughness was improved by 30.82%, 16.67%, 14.06%, 26.17%, and 16.67%, respectively. Meanwhile, the prediction accuracy of tool wear was improved by 46.74%, 39.57%, 41.51%, 38.68%, and 39.57%, respectively. For practical engineering application, the dimensional deviation and surface quality of the machined parts can be controlled through the established MTL model
Remote Sensing of Tropical Rainforest Biomass Changes in Hainan Island, China from 2003 to 2018
The largest area of tropical rainforests in China is on Hainan Island, and it is an important part of the world’s tropical rainforests. The structure of the tropical rainforests in Hainan is complex, the biomass density is high, and conducting ground surveys is difficult, costly, and time-consuming. Remote sensing is a good monitoring method for biomass estimation. However, the saturation phenomenon of such data from different satellite sensors results in low forest biomass estimation accuracy in tropical rainforests with high biomass density. Based on environmental information, the biomass of permanent sample plots, and forest age, this study established a tropical rainforest database for Hainan. Forest age and 14 types of environmental information, combined with an enhanced vegetation index (EVI), were introduced to establish a tropical rainforest biomass estimation model for remote sensing that can overcome the saturation phenomenon present when using remote sensing data. The fitting determination coefficient R2 of the model was 0.694. The remote sensing estimate of relative bias was 2.29%, and the relative root mean square error was 35.41%. The tropical rainforest biomass in Hainan Island is mainly distributed in the central mountainous and southern areas. The tropical rainforests in the northern and coastal areas have been severely damaged by tourism and real estate development. Particularly in low-altitude areas, large areas of tropical rainforest have been replaced by economic forests. Furthermore, the tropical rainforest areas in some cities and counties have decreased, affecting the increase in tropical rainforest biomass. On Hainan Island, there were few tropical rainforests in areas with high rainfall. Therefore, afforestation in these areas could maximize the ecological benefits of tropical rainforests. To further strengthen the protection, there is an urgent need to establish a feasible, reliable, and effective tropical rainforest loss assessment system using quantitative scientific methodologies
Analytical parameters for direct and indirect UV detection of BCAAs.
<p>Analytical parameters for direct and indirect UV detection of BCAAs.</p
Quantitation of underivatized branched-chain amino acids in sport nutritional supplements by capillary electrophoresis with direct or indirect UV absorbance detection - Fig 2
<p>Indirect UV detection of BCAAs affected by the concentration of PAS (A) and the wavelength (B). The optimization process in A was obtained by different PAS concentration in 40.0 mM β-CD, 2.0 mmol/L Na<sub>2</sub>HPO<sub>4</sub> (pH12.2), and detected at 264 nm. The separation profiles in B were at optimal BGE. Sample: 1.0 mmol/L Leu, Ile and Val. Others as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0179892#pone.0179892.g001" target="_blank">Fig 1</a>.</p
Design, synthesis, and anti-HIV evaluation of novel triazine derivatives targeting the entrance channel of the NNRTI binding pocket
A novel series of triazine derivatives targeting the entrance channel of the HIV-1 non-nucleoside reverse transcriptase inhibitor binding pocket (NNIBP) were designed and synthesized on the basis of our previous work. The results of a cell-based antiviral screening assay indicated that most compounds showed good-to-moderate activity against wild-type HIV-1 with EC50 values within the concentration range of 0.0078-0.16 μm (compound DCS-a4, EC50  = 7.8 nm). Some compounds displayed submicromolar activity against the K103N/Y181C resistant mutant strain (such as compound DCS-a4, EC50  = 0.65 μm). Molecular modeling studies confirmed that the new compounds could bind into the NNIBP similarly as the lead compound, and the newly introduced flexible heterocycles could occupy the entrance channel effectively. In addition, the preliminary structure-activity relationship and the RT inhibitory assay are presented in this study.status: publishe