1,720,966 research outputs found
An insulating material in a structured host enables sustainable formation of a granular Li metal for highly durable Li metal battery
No full text© 2022 Elsevier B.V.For using Li metal anode, controlling Li metal morphology for long-term cycles is an essential requirement, but the porous Li metal easily form due to a dendritic Li growth. Here, we report on a novel strategy to reversibly form a granular Li metal by confining Li deposition sites and controlling the Li metal morphology via a structured functional host that is composed of small portion of a Li-alloying region and large portion of an insulating region. The insulating region confines the nucleation sites to the Li-alloying region because the nucleation cannot occur in the insulating region, and strongly affects the growth/morphology of the Li metal because the insulating particles mitigate the Li+ concentration around the Li-alloying particles. The persistent effects of the confinement and control of the Li metal morphology enable to sustainably form the granular Li metal. The Cu electrode with the functional host structure achieve Coulombic efficiency of >98% over 500 cycles, and can reversibly deposit Li metal with LiCoO2 cathode even in typical standard carbonate electrolytes. The findings reveal novel capabilities of insulating materials for sustainable use of Li and provide a new avenue for designing practical use of Li metal for durable Li metal batteries.11Nsciescopu
Stereo vision with image-guided structured-light pattern matching
No full textAn accurate stereo matching method developed by exploiting the two techniques, discrete-coded structured-light projection and image-guided cost volume filtering, is proposed. The former increases the distinctiveness of pixels by projecting a discrete pattern to the scene, and the latter helps to recover accurate object boundaries. In addition, a previous fast cost volume filtering approach is extended to better preserve slanted surfaces, and a suitable post-processing algorithmis also suggested for the proposed method. The performance of the proposed method is experimentally verified by comparing the results with those of other algorithms qualitatively and quantitatively in an indoor environment.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Tandem Mass Spectrometry를 활용한 혈청, 소변, 양봉 시료 및 대표작물 중 다종농약다성분 동시분석
Get PDF학위논문 (박사)-- 서울대학교 대학원 : 농업생명과학대학 농생명공학부, 2018. 8. 김정한.Pesticides are used for the effective control of pests, microorganisms, and weeds from crops and have contributed to food security. It is necessary to determine as many pesticides as possible in human, the environment, and agricultural products due to the intrinsic toxicity and ecotoxicity of pesticides. In this study, a tandem mass spectrometry coupled to a gas chromatography (GC-MS/MS) or liquid chromatography (LC-MS/MS) was utilized to determine approximately four hundreds of pesticides in biological samples (serum and urine), apiculture samples (bee, pollen, and honey), and representative crops (pepper, orange, brown rice, and soybean). The scheduled multiple reaction monitoring (MRM) of the tandem mass spectrometer was employed in all methodologies to achieve rapid and simultaneous analysis and to obtain optimal sensitivity and selectivity of target analytes. The preparation methods for serum and urine were selected by comparing with the three versions of Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) procedures. The optimized method was validated for 379 (serum) and 380 (urine) pesticides using LC-MS/MS. As a result, 94.5% (serum) and 95.8% (urine) of the total pesticides satisfied a limit of quantitation of 10 ng/mL. The established analytical method was applied to GC-MS/MS amenable pesticides (54 for serum and 55 for urine) and 53 analytes showed a limit of quantitation of 10 ng/mL. It was enough low sensitivity to determine pesticides in biological samples for forensic, clinical, and occupational exposure application. Apiculture samples, that is, bee (dead, healthy imago, and larva), pollen, and honey were treated by optimized QuEChERS methods. Among the pesticide multiresidues, three neonicotinoids (clothianidin, imidacloprid, and thiamethoxam), which are expected to be totally banned for outdoor use in the European Union (EU) by the end of 2018, were subjected to method validation. The limit of quantitation of each analyte was 1 ng/g and it was sufficiently low to determine pesticide residues below the levels of acute oral toxicity (LD50) of the bee. The field monitoring was conducted in two area near the apple orchard and pepper field in 2014. The analysis of the neonicotinoids and 391 multiresidue pesticides in apiculture samples were carried out. Based on residue levels, comprehensive honey bee exposure near farmland was able to be understood. Four representative crops were treated using miniaturized Multiclass Pesticide Multiresidue Method (No. 2) of the Korea Food Code, and the analytical method was evaluated for 384 pesticides using GC-MS/MS. As a result, 95.1-99.5% of the total pesticides satisfied the method limit of quantitation
Preface 1
Chapter I. Development and Validation of Pesticide Multiresidue Analysis in Human Serum and Urine Using LC-MS/MS and GC-MS/MS. 3
Introduction 4
Pesticide intoxication. 4
Pesticide analysis in biological samples. 5
Advantage of the tandem mass spectrometry 10
Preparation methodology for biological sample. 10
Purpose of the present study 12
Part 1. Development and Validation of Pesticide Multiresidue Analysis in Human Serum and Urine Using LC-MS/MS 13
Materials and Methods 14
Chemicals and reagents 14
Preparation of standard solutions 14
LC-MS/MS parameters 15
Comparison of three versions of QuEChERS. 16
Final established sample preparation 17
Validation of analytical methods. 17
Safety information 19
Results and Discussion. 20
Optimization of multiple reaction monitoring (MRM) in LC-MS/MS. 20
Relationship between partition-coefficient and retention time. 21
Optimization of sample extraction step 26
Method validation 38
Limit of quantitation (LOQ) 38
Linearity of calibration. 44
Accuracy and precision. 50
Recovery. 64
Matrix effect 79
Conclusions. 90
Part 2. Development and Validation of Pesticide Multiresidue Analysis in Human Serum and Urine Using GC-MS/MS. 91
Materials and Methods 92
Chemicals and reagents 92
GC-MS/MS instrumental conditions 92
Establishment of scheduled MRM 93
Sample preparation using modified QuEChERS 94
Validation of methodology 94
Safety information 95
Results and Discussion. 96
Characteristics of pesticide to be studied 96
Optimization of MRM 99
Determination of final selected pesticides to be validated 102
Validation of analytical method 103
Limit of quantitation (LOQ) and linearity of calibration. 103
Accuracy and precision. 110
Recovery. 111
Matrix effect 114
Conclusions. 115
Chapter II. Analysis of Neonicotinoids (Clothianidin, Imidacloprid, and Thiamethoxam) and Pesticide Multiresidues in Honey Bee, Pollen, and Honey Using LC-MS/MS and GC-MS/MS. 119
Introduction 120
Benefits from honey bee. 120
Honey bee Colony Collapse Disorder (CCD) 120
Neonicotinoid, a suspicious chemical leading to CCD. 121
Analysis of pesticide residues in apiculture samples 122
Purpose of the present study 123
Materials and Methods 126
Chemicals and reagents 126
Preparation of matrix-matched standards. 127
Sample collection. 127
Instrumental conditions of LC-MS/MS and GC-MS/MS. 133
LC-MS/MS 133
GC-MS/MS. 134
MRM optimization in LC-MS/MS and GC-MS/MS 135
Sample preparation. 136
Method validation for clothianidin, imidacloprid, and thiamethoxam 137
Pesticide multiresidue screening in bee, pollen, and honey. 137
Statistical analysis 138
Safety information 138
Results and Discussion. 139
Body weights of honey bees. 139
MRM optimization. 141
Method validation for neonicotinoids. 143
Analysis of neonicotinoids (clothianidin, imidaclprid, and thiamethoxam) in bee, pollen, and honey. 145
Bee 145
Pollen 154
Honey 162
Analysis of pesticide multiresidues in bee, pollen, and honey. 164
Conclusions. 180
Chapter III. Multiresidue Analysis for 384 Pesticides in Pepper, Orange, Brown Rice, and Soybean Using Florisil Solid-phase Extraction and GC-MS/MS 183
Introduction 184
Introduction of positive list system. 184
Tandem mass spectrometry for pesticide multiresidue analysis 186
Solid-phase extraction for pesticide purification 192
Multiclass Pesticide Multiresidue Method (No. 2) . 193
Purpose of the present study 195
Materials and Methods 196
Chemicals and reagents 196
Preparation of matrix-matched standard. 196
Instrumental conditions of GC-MS/MS 197
Multiple reaction monitoring (MRM) profile optimization 198
Sample preparation of pepper, orange, brown rice, and soybean 198
Defatting procedure in soybean using n-hexane/acetonitrile partitioning. 199
Method validation 199
Results and Discussion. 201
MRM optimization and selection of pesticides to be validated. 201
Characteristics of 384 pesticides. 202
Comparison of the preparation procedures with/without n-hexane/ acetonitrile partitioning 203
Method limit of quantitation (MLOQ) 206
Instrumental repeatability. 209
Linearity of calibration. 210
Recovery. 215
Matrix effect. 224
Conclusions. 225
Supplementary Information. 228
References. 255
초록. 273Docto
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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