Perspectives in science最新文献

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Biocatalytic retrosynthesis: Redesigning synthetic routes to high-value chemicals 生物催化反合成:重新设计高价值化学品的合成路线
Perspectives in science Pub Date : 2016-12-01 DOI: 10.1016/j.pisc.2016.04.106
Anthony P. Green, Nicholas J. Turner
{"title":"Biocatalytic retrosynthesis: Redesigning synthetic routes to high-value chemicals","authors":"Anthony P. Green,&nbsp;Nicholas J. Turner","doi":"10.1016/j.pisc.2016.04.106","DOIUrl":"10.1016/j.pisc.2016.04.106","url":null,"abstract":"<div><p>Modern tools for enzyme discovery combined with the development of increasingly reliable strategies for protein engineering have greatly expanded the range of enzymes with suitable properties for practical applications. This situation presents enormous opportunities for the design of sustainable biocatalytic strategies for the production of high-value chemicals. Here, we highlight recent contributions from our laboratory concerning ω-transaminases and monoamine oxidases, two enzyme classes that have been exploited for the industrial scale production of active pharmaceutical ingredients or key chiral intermediates. Firstly, we describe the development of novel ‘smart’ amine donors which overcome inherent challenges associated with controlling the equilibrium position of ω-TA catalyzed processes. Subsequently, we demonstrate how engineered variants of monoamine oxidase developed in our laboratory have been applied as biocatalysts for the synthesis of a diverse range of active pharmaceutical ingredients and alkaloid natural products. Through these illustrative examples, we hope to promote the wider application of enzymes within the synthetic community.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"9 ","pages":"Pages 42-48"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.106","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73670234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 41
In search of lost time constants and of non-Michaelis–Menten parameters 寻找丢失的时间常数和非米切里斯-门腾参数
Perspectives in science Pub Date : 2016-12-01 DOI: 10.1016/j.pisc.2016.03.024
Maria F. Pinto , Pedro M. Martins
{"title":"In search of lost time constants and of non-Michaelis–Menten parameters","authors":"Maria F. Pinto ,&nbsp;Pedro M. Martins","doi":"10.1016/j.pisc.2016.03.024","DOIUrl":"10.1016/j.pisc.2016.03.024","url":null,"abstract":"<div><p>Upon completing 100 years since it was published, the work <em>Die Kinetik der Invertinwirkung</em> by Michaelis and Menten (MM) was celebrated during the 6th Beilstein ESCEC Symposium 2013. As the 7th Beilstein ESCEC Symposium 2015 debates enzymology in the context of complex biological systems, a post-MM approach is required to address cell-like conditions that are well beyond the steady-state limitations. The present contribution specifically addresses two hitherto ambiguous constants whose interest was, however, intuited in the original MM paper: (i) the characteristic time constant <em>τ</em><sub>∞</sub>, which can be determined using the late stages of any progress curve independently of the substrate concentration adopted; and (ii) the dissociation constant <em>K</em><sub><em>S</em></sub>, which is indicative of the enzyme–substrate affinity and completes the kinetic portrayal of the Briggs–Haldane reaction scheme. The rationale behind <em>τ</em><sub>∞</sub> and <em>K</em><sub><em>S</em></sub> prompted us to revise widespread concepts of enzyme's efficiency, defined by the specificity constant <em>k</em><sub><em>cat</em></sub>/<em>K</em><sub><em>M</em></sub>, and of the Michaelis constant <em>K</em><sub><em>M</em></sub> seen as the substrate concentration yielding half-maximal rates. The alternative definitions here presented should help recovering the wealth of published <em>k</em><sub><em>cat</em></sub>/<em>K</em><sub><em>M</em></sub> and <em>K</em><sub><em>M</em></sub> data from the criticism that they are subjected. Finally, a practical method is envisaged for objectively determining enzyme's activity, efficiency and affinity – (EA)<sup>2</sup> – from single progress curves. The (EA)<sup>2</sup> assay can be conveniently applied even when the concentrations of substrate and enzyme are not accurately known.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"9 ","pages":"Pages 8-16"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.03.024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87431725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 8
Science education with handheld devices: A comparison of Nintendo WiiMote and iPod touch for kinematics learning 手持设备的科学教育:任天堂WiiMote和iPod touch运动学学习的比较
Perspectives in science Pub Date : 2016-12-01 DOI: 10.1016/j.pisc.2016.01.008
K. Hochberg , J. Kuhn , A. Müller
{"title":"Science education with handheld devices: A comparison of Nintendo WiiMote and iPod touch for kinematics learning","authors":"K. Hochberg ,&nbsp;J. Kuhn ,&nbsp;A. Müller","doi":"10.1016/j.pisc.2016.01.008","DOIUrl":"10.1016/j.pisc.2016.01.008","url":null,"abstract":"<div><p>Experiential science learning based on the in-built sensors of handheld devices such as smartphones, tablet computer and game consoles has seen quite a strong development in recent years. In particular, such devices with internal acceleration sensors offer an innovative approach to kinematics learning in classroom physics, a notoriously difficult topic for pupils. In view of research and teaching in this domain, the practical advantages and disadvantages of two such devices, the Nintendo WiiMote and the Apple iPod touch, are discussed.</p><p>Beyond the specific examples, this comparison of the advantages and disadvantages of two different “philosophies” of instructional technology with regard to their use in science learning experiments provides arguments for discussions and decisions related to such technology in other and future settings, which can be of interest to both researchers and practitioners in the field.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"10 ","pages":"Pages 13-18"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.01.008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80156946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 10
From enzymology to systems biology and back – Epilog 从酶学到系统生物学,再到后记
Perspectives in science Pub Date : 2016-12-01 DOI: 10.1016/j.pisc.2015.11.057
Peter Halling
{"title":"From enzymology to systems biology and back – Epilog","authors":"Peter Halling","doi":"10.1016/j.pisc.2015.11.057","DOIUrl":"10.1016/j.pisc.2015.11.057","url":null,"abstract":"","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"9 ","pages":"Pages 67-69"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2015.11.057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77507687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The bacterial catabolism of polycyclic aromatic hydrocarbons: Characterization of three hydratase-aldolase-catalyzed reactions 细菌对多环芳烃的分解代谢:三个水合酶-醛缩酶催化反应的表征
Perspectives in science Pub Date : 2016-12-01 DOI: 10.1016/j.pisc.2016.03.025
Jake A. LeVieux, William H. Johnson Jr., Kaci Erwin, Wenzong Li, Yan Jessie Zhang, Christian P. Whitman
{"title":"The bacterial catabolism of polycyclic aromatic hydrocarbons: Characterization of three hydratase-aldolase-catalyzed reactions","authors":"Jake A. LeVieux,&nbsp;William H. Johnson Jr.,&nbsp;Kaci Erwin,&nbsp;Wenzong Li,&nbsp;Yan Jessie Zhang,&nbsp;Christian P. Whitman","doi":"10.1016/j.pisc.2016.03.025","DOIUrl":"10.1016/j.pisc.2016.03.025","url":null,"abstract":"<div><p>Polycyclic aromatic hydrocarbons (PAHs) are highly toxic, pervasive environmental pollutants with mutagenic, teratogenic, and carcinogenic properties. There is interest in exploiting the nutritional capabilities of microbes to remove PAHs from various environments including those impacted by improper disposal or spills. Although there is a considerable body of literature on PAH degradation, the substrates and products for many of the enzymes have never been identified and many proposed activities have never been confirmed. This is particularly true for high molecular weight PAHs (e.g., phenanthrene, fluoranthene, and pyrene). As a result, pathways for the degradation of these compounds are proposed to follow one elucidated for naphthalene with limited experimental verification. In this pathway, ring fission produces a species that can undergo a non-enzymatic cyclization reaction. An isomerase opens the ring and catalyzes a <em>cis</em> to <em>trans</em> double bond isomerization. The resulting product is the substrate for a hydratase-aldolase, which catalyzes the addition of water to the double bond of an α,β-unsaturated ketone, followed by a retro-aldol cleavage. Initial kinetic and mechanistic studies of the hydratase-aldolase in the naphthalene pathway (designated NahE) and two hydratase-aldolases in the phenanthrene pathway (PhdG and PhdJ) have been completed. Crystallographic work on two of the enzymes (NahE and PhdJ) provides a rudimentary picture of the mechanism and a platform for future work to identify the structural basis for catalysis and the individual specificities of these hydratase-aldolases.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"9 ","pages":"Pages 33-41"},"PeriodicalIF":0.0,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.03.025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87381499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Multi-Level Optimization in Encoding to Balance Video Compression and Retention of 8K Resolution 平衡视频压缩和保持8K分辨率的多层优化编码
Perspectives in science Pub Date : 2016-09-01 DOI: 10.1016/j.pisc.2016.04.069
S.V.N. Murthy , B.K. Sujatha
{"title":"Multi-Level Optimization in Encoding to Balance Video Compression and Retention of 8K Resolution","authors":"S.V.N. Murthy ,&nbsp;B.K. Sujatha","doi":"10.1016/j.pisc.2016.04.069","DOIUrl":"10.1016/j.pisc.2016.04.069","url":null,"abstract":"<div><p>This paper presents a technique that aimed to accomplish an efficient balance between video compression using H.265 protocol and retention of 8K resolution. The study implements multi-level of optimization in the encoding process using H.265 where JPEG2000 standards play a crucial role. The study also applies a novel concept of orthogonal projection that manages pixels metadata required in every frame transition followed by motion compensation. By using multiple file formats of 30 video datasets, the outcome of the study is found to be accomplishing approximately 49% of enhancement in data quality and around 59% of improvement in video compression in comparison to the existing techniques of HEVC-based video compression.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"8 ","pages":"Pages 338-344"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55213665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
An analytical study on performance of a diagrid structure using nonlinear static pushover analysis 用非线性静力推覆分析方法对网格结构的性能进行了分析研究
Perspectives in science Pub Date : 2016-09-01 DOI: 10.1016/j.pisc.2016.04.004
Kiran Kamath, Sachin Hirannaiah, Jose Camilo Karl Barbosa Noronha
{"title":"An analytical study on performance of a diagrid structure using nonlinear static pushover analysis","authors":"Kiran Kamath,&nbsp;Sachin Hirannaiah,&nbsp;Jose Camilo Karl Barbosa Noronha","doi":"10.1016/j.pisc.2016.04.004","DOIUrl":"10.1016/j.pisc.2016.04.004","url":null,"abstract":"<div><p>In this study, an attempt has been made to study the performance characteristics of diagrid structures using nonlinear static pushover analysis. The models studied are circular in plan with aspect ratio <em>H</em>/<em>B</em> (where <em>H</em> is total height and <em>B</em> is the base width of structure) varying from 2.67 to 4.26. The three different angles of external brace considered are 59°, 71° and 78° (<span>Kim et al., 2010</span>). The width of the base is kept constant at 12<!--> <!-->m and height of the structure is varied accordingly. The nonlinear behaviour of the elements is modelled using plastic hinges based on moment–curvature relationship as described in <span>FEMA 356</span> guidelines. Seismic response of structure in terms of base shear and roof displacement corresponding to performance point were evaluated using nonlinear static analysis and the results are compared. For 71° brace angle model base shear at performance shows an increase in all the aspect ratio considered in the study. The performance of the structure is influenced by brace angle and aspect ratio.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"8 ","pages":"Pages 90-92"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75869121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Introduction of fractional elements for improvising the performance of PID controller for heating furnace using AMIGO tuning technique 介绍了利用AMIGO整定技术改进加热炉PID控制器性能的分数元件
Perspectives in science Pub Date : 2016-09-01 DOI: 10.1016/j.pisc.2016.04.065
Amlan Basu, Sumit Mohanty , Rohit Sharma
{"title":"Introduction of fractional elements for improvising the performance of PID controller for heating furnace using AMIGO tuning technique","authors":"Amlan Basu,&nbsp;Sumit Mohanty ,&nbsp;Rohit Sharma","doi":"10.1016/j.pisc.2016.04.065","DOIUrl":"10.1016/j.pisc.2016.04.065","url":null,"abstract":"<div><p>The paper demonstrates about melioration of integer order and fractional order model of heating furnace. Both models are being placed in closed loop along with the proportional integral derivative (PID) controller and fractional order proportional integral derivative (FOPID) controller so that the various time domain performance characteristics of the heating furnace can be meliorated. The tuning parameters (<em>K</em><sub>p</sub>, <em>K</em><sub>i</sub> and <em>K</em><sub>d</sub>) of the controllers has been found using the Astrom-Hagglund tuning technique and the differ-integrals (<em>λ</em> and <em>μ</em>) are found using the Nelder-Mead optimisation technique.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"8 ","pages":"Pages 323-326"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.065","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74686244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Energy consumption in Hodgkin–Huxley type fast spiking neuron model exposed to an external electric field 外加电场作用下霍奇金-赫胥黎型快速尖峰神经元模型的能量消耗☆
Perspectives in science Pub Date : 2016-09-01 DOI: 10.1016/j.pisc.2016.04.015
K. Usha , M.K. Sreepriya , P.A. Subha
{"title":"Energy consumption in Hodgkin–Huxley type fast spiking neuron model exposed to an external electric field","authors":"K. Usha ,&nbsp;M.K. Sreepriya ,&nbsp;P.A. Subha","doi":"10.1016/j.pisc.2016.04.015","DOIUrl":"10.1016/j.pisc.2016.04.015","url":null,"abstract":"<div><p>This paper evaluates the change in metabolic energy required to maintain the signalling activity of neurons in the presence of an external electric field. We have analysed the Hodgkin–Huxley type conductance based fast spiking neuron model as electrical circuit by changing the frequency and amplitude of the applied electric field. The study has shown that, the presence of electric field increases the membrane potential, electrical energy supply and metabolic energy consumption. As the amplitude of applied electric field increases by keeping a constant frequency, the membrane potential increases and consequently the electrical energy supply and metabolic energy consumption increases. On increasing the frequency of the applied field, the peak value of membrane potential after depolarization gradually decreases as a result electrical energy supply decreases which results in a lower rate of hydrolysis of ATP molecules.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"8 ","pages":"Pages 132-134"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78416224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Improving the performance of jaggery making unit using solar energy 提高太阳能制钢机组的性能
Perspectives in science Pub Date : 2016-09-01 DOI: 10.1016/j.pisc.2016.04.019
Lakshmi Pathi Jakkamputi, Mohan Jagadeesh Kumar Mandapati
{"title":"Improving the performance of jaggery making unit using solar energy","authors":"Lakshmi Pathi Jakkamputi,&nbsp;Mohan Jagadeesh Kumar Mandapati","doi":"10.1016/j.pisc.2016.04.019","DOIUrl":"10.1016/j.pisc.2016.04.019","url":null,"abstract":"<div><p>The thermal performance of open earth pan furnace used conventionally for preparing jaggery (gur) is very low. Dry bagasse is used as a fuel to produce heat in a combustion process in the open earth furnace. The energy loss due to inefficient combustion process, the energy loss through exhaust gases and other losses due to furnace wall, convection and radiation bring the thermal efficiency of open earth pan furnace to a low value. Certain quantity of energy produced in combustion process is used to sensibly heat the sugarcane juice to its evaporation temperature. Solar collectors can supply the sensible heat required to raise the sugarcane juice temperature up to its boiling point, thereby reducing the total quantity of heat required in preparing the <em>jaggery</em>. Solar drier can be used to supply hot air required for the combustion process to burn the bagasse in more efficient manner. This paper presents analytical calculations done to study the performance improvement of the jaggery making unit using solar collector and solar drier.</p></div>","PeriodicalId":92112,"journal":{"name":"Perspectives in science","volume":"8 ","pages":"Pages 146-150"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.pisc.2016.04.019","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81896769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 32
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