scholarly journals Advances in Design Strategies of Multiplex Electrochemical Aptasensors

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 161
Author(s):  
Iwona Grabowska ◽  
Maria Hepel ◽  
Katarzyna Kurzątkowska-Adaszyńska
Keyword(s):  
Simultaneous Detection ◽  
High Sensitivity ◽  
Clinical Diagnostics ◽  
The Other ◽  
Design Strategies ◽  
Detection Systems ◽  
Advantages And Disadvantages ◽  
Target Analytes ◽  
The One

In recent years, the need for simple, fast, and economical detection of food and environmental contaminants, and the necessity to monitor biomarkers of different diseases have considerably accelerated the development of biosensor technology. However, designing biosensors capable of simultaneous determination of two or more analytes in a single measurement, for example on a single working electrode in single solution, is still a great challenge. On the other hand, such analysis offers many advantages compared to single analyte tests, such as cost per test, labor, throughput, and convenience. Because of the high sensitivity and scalability of the electrochemical detection systems on the one hand and the specificity of aptamers on the other, the electrochemical aptasensors are considered to be highly effective devices for simultaneous detection of multiple-target analytes. In this review, we describe and evaluate multi-label approaches based on (1) metal quantum dots and metal ions, (2) redox labels, and (3) enzyme labels. We focus on recently developed strategies for multiplex sensing using electrochemical aptasensors. Furthermore, we emphasize the use of different nanomaterials in the construction of these aptasensors. Based on examples from the existing literature, we highlight recent applications of multiplexed detection platforms in clinical diagnostics, food control, and environmental monitoring. Finally, we discuss the advantages and disadvantages of the aptasensors developed so far, and debate possible challenges and prospects.

Hybrid polymer composite materials. Part 2. Preparation technology

2020 ◽  
pp. 8-13
Keyword(s):  
Composite Materials ◽  
Impact Toughness ◽  
Polymer Composites ◽  
The Other ◽  
Polymer Materials ◽  
Hybrid Polymer ◽  
Preparation Technology ◽  
Advantages And Disadvantages ◽  
Hybrid Polymer Composite ◽  
The One

The main methods (pressing and winding) of the processing of hybrid polymer composites to obtain items were examined. Advantages and disadvantages of the methods were noted. Good combinations of different-module fibers (carbon, glass, boron, organic) in hybrid polymer materials are described, which allow one to prepare materials with high compression strength on the one hand, and to increase fracture energy of samples and impact toughness on the other hand.

A Validated 2D-LC-UV Method for Simultaneous Determination of Imatinib and N-demethylimatinib in Plasma and Its Clinical Application for Therapeutic Drug Monitoring with GIST Patients

2020 ◽  
Vol 17 ◽  
Author(s):  
Houli Li ◽  
Di Zhang ◽  
Xiaoliang Cheng ◽  
Qiaowei Zheng ◽  
Kai Cheng ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
One Dimension ◽  
Therapeutic Drug ◽  
Plasma Samples ◽  
Column Temperature ◽  
Injection Volume ◽  
Target Analytes ◽  
The One ◽  
Middle Column

Background: The trough concentration (Cmin) of Imatinib (IM) is closely related to the treatment outcomes and adverse reactions of patients with gastrointestinal stromal tumors (GIST). However, the drug plasma level has great interand intra-individual variability, and therapeutic drug monitoring (TDM) is highly recommended. Objective: To develop a novel, simple, and economical two-dimensional liquid chromatography method with ultraviolet detector (2D-LC-UV) for simultaneous determination of IM and its major active metabolite, N-demethyl imatinib (NDIM) in human plasma, and then apply the method for TDM of the drug. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Method: Sample was processed by simple protein precipitation. Two target analytes were separated on the one-dimension column, captured on the middle column, and then transferred to the two-dimension column for further analysis. The detection was performed at 264 nm. The column temperature was maintained at 40˚C and the injection volume was 500 μL. Totally 32 plasma samples were obtained from patients with GIST who were receiving IM. Conclusion: The novel 2D-LC-UV method is simple, stable, highly automated and independent of specialized technicians, which greatly increases the real-time capability of routine TDM for IM in hospital.

scholarly journals Determination of the Height of Hard X-Ray Sources in the Solar Atmosphere by Measurement of Photospheric Albedo Photons

1975 ◽  
Vol 68 ◽  
pp. 239-241
Author(s):  
John C. Brown ◽  
H. F. Van Beek
Keyword(s):  
Solar Atmosphere ◽  
The Other ◽  
X Ray ◽  
Theoretical Predictions ◽  
Source Models ◽  
The One

SummaryThe importance and difficulties of determining the height of hard X-ray sources in the solar atmosphere, in order to distinguish source models, have been discussed by Brown and McClymont (1974) and also in this Symposium (Brown, 1975; Datlowe, 1975). Theoretical predictions of this height, h, range between and 105 km above the photosphere for different models (Brown and McClymont, 1974; McClymont and Brown, 1974). Equally diverse values have been inferred from observations of synchronous chromospheric EUV bursts (Kane and Donnelly, 1971) on the one hand and from apparently behind-the-limb events (e.g. Datlowe, 1975) on the other.

Cycles in symbol production? A new model to explain concentration, diversity and innovation in the music industry

Popular Music ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 55-93 ◽  
Author(s):  
Michael Christianen
Keyword(s):  
Negative Correlation ◽  
Music Industry ◽  
The Other ◽  
Recording Industry ◽  
Cultural Goods ◽  
New Model ◽  
Advantages And Disadvantages ◽  
Factors Influencing ◽  
Using Data ◽  
The One

With the publication of the article ‘Cycles in symbol production’ (Peterson and Berger 1975) a discussion started concerning the advantages and disadvantages of the production of cultural goods under market conditions. The analysis by Peterson and Berger showed a negative correlation between concentration in the recording industry, on the one hand, and the diversity and innovativeness of the music, on the other. Repetition of the analysis using data from the 1980s (Burnett 1990; Lopes 1992) has shown that for this period Peterson and Berger's hypotheses should be rejected. Is there a connection between concentration and diversity and innovation? Are there cycles in symbol production? There seems to be no conclusive answer. In this article, I will attempt to clear up this matter. First, I will repeat the analysis of the relation between concentration and diversity/innovation, using the same model as Peterson and Berger, but with different definitions for the variables concentration, diversity and innovation. Then I will suggest a new model, which can be helpful in uncovering other factors influencing diversity and innovation in the music industry. I will come to that later. Let me first give the reader a brief overview of previous research.

Augustus and the Senate: 23 B.C.

Antichthon ◽  
1985 ◽  
Vol 19 ◽  
pp. 57-67 ◽  
Author(s):  
W.K. Lacey
Keyword(s):  
The Other ◽  
The One ◽  
Res Publica

While the exact meaning of Res Gestae 34, the powers of Augustus at various moments in his principate, and the significance of his auctoritas have been extensively argued, more practical questions about how his political arrangements might have been set into action have not generally excited much interest. In 1974 I put forward a suggestion about how the so-called first settlement of 27 B.C. came about. It was, in brief, that Octavian, as he then was, used the traditional consular mechanisms, and proposed for debate in the Senate a motion, de provinciis consularibus, and this explains why, on the one hand, the result of the debate was that he had provinces allocated to him, and, on the other, claims could be made that the res publica was restored, because one of the things which characterized res publica (as distinct from dictatorship or triumviral rule) was that the determination of who should command which army stationed in the provinces now lay, ostensibly at least, with the publicum consilium, the Senate.

Table II : Quantitative determination of carbonyl compounds at different odour sources (concentrations in ppb) Rendering plant Gelatine plant neighbourhood neighbourhood Formaldehyde 40 16 Acetaldehyde 39 24 Acetone 36 73 Prcpanal 10 -Isobutyraldehyde 10 30 Pentanal 15 19 Hexanal 3.52 Heptanal 12.5 Octanal 10.5 Nonanal 1 2 acids (figure 7). However extractions always involve a serious decrease in sensitivity, while evaporation of the extract produces a solution in 0.1-0.5 ml of solvent, and only 1 pi of it can be brought in the gas chromatograph. Therefore work is in progress to enhance sensitivity by converting acids in­ to halogenated derivatives, which can be GC-analysed with the more sensitive electron-capture detector. For thiols a similar procedure is investigated as with aldehydes. One possibility is absorption of thiols in an alkaline solution and reaction with 2,4-dinitrochlorobenzene, yielding 2,4-dinitrofenylsulfides, which are analysed by HPLC (9). Sane improvements on removal of reagents at the one hand and on separation of sane by-products on the other hand have to be achieved in order to in­ crease the sensitivity with another factor of ten. 5. CONCLUSION The actual scope and limitations of chemical analysis of odour show that all problems can be tackled as far as emission is concerned. For iititiission measurements seme progress is necessary, but there is no essential reason why chemical analysis would be unable to attain the desired sensitivity for all types of odorants. There is no doubt that in a few years the last dif­ ficulties will be solved. In order to achieve real control of odour nui­ sance, automatic measurement is necessary on a long time basis. There again seme technical development is to be expected. Does this mean that machines are going to decide if an odour is pre­ sent or not? By no means, while the population will always be the reference, and psychophysical measurements will be necessary to make chemical analysis possible.

1986 ◽  
pp. 171-171
Keyword(s):  
Chemical Analysis ◽  
Quantitative Determination ◽  
Alkaline Solution ◽  
Automatic Measurement ◽  
The Other ◽  
Long Time ◽  
Time Basis ◽  
The One ◽  
By Products

scholarly journals DEVELOPMENT OF THE MODEL OF STUDENTS’ INDEPENDENT WORK UNDER CONDITIONS OF DISTANCE LEARNING

2021 ◽  
pp. 273-289
Author(s):  
Olena Osadcha
Keyword(s):  
Distance Learning ◽  
Information Technologies ◽  
The Other ◽  
Advantages And Disadvantages ◽  
Other Hand ◽  
The One ◽  
Independent Work ◽  
Further Development

The article deals with the development of the model of students’ independent work under conditions of distance learning. The importance of the research into this problem is determined, on the one hand, by the growing possibilities of using various information technologies and, on the other hand by the necessity to adapt to the conditions of today’s world where independent work of students is becoming increasingly important. The advantages and disadvantages of distance learning have been explored. The author studied the role of independent work in the formation of the professional competences of students. The issue of modeling in the area of education has been tackled. The approaches to the development of the model of independent work have been identified and analyzed. The components of the model, such as the goal, the tasks, the content, the methods, the means and evaluation of results have been determined and characterized. The prospects of further development of this research are related to the exploration of models of independent work of students majoring in different areas.

scholarly journals Systematization and analysis of approaches to assessing the competitiveness of business entities

2018 ◽  
Vol 193 ◽  
pp. 05077
Author(s):  
Vadim Krivorotov ◽  
Aleksandr Tarasenko ◽  
Evgeniy Tikhanov ◽  
Petr Chepur ◽  
Alesya Gruchenkova
Keyword(s):  
The Other ◽  
Multivariate Models ◽  
Management Decisions ◽  
Competitive Position ◽  
Advantages And Disadvantages ◽  
Other Hand ◽  
Business Entities ◽  
The One

Assessment of competitiveness is an objective need of every business entity seeking to maintain or improve their own competitive position and make informed management decisions. The authors propose to classify the diversity of methods of assessment of the competitiveness of the enterprise through three main approaches: graphic, factor and value. In order to identify the advantages and disadvantages of each of the approaches described by the authors, the content of the main methods used in the study was analyzed. It is concluded that there is no universal tool for assessing the competitiveness of the enterprise, which is due to, on the one hand, the limited reliability and low estimates obtained by using matrix and product methods, and on the other hand, the complexity and cost of the estimates using existing multivariate models.

scholarly journals XXII. On the extensive atmosphere of Mars

1831 ◽  
Vol 121 ◽  
pp. 417-422 ◽  
Keyword(s):  
The Other ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
Formed Part ◽  
The One

That several of the planets as well as that which we inhabit are surrounded by atmosphere, astronomical observations have long since established; the extent, however, to which in particular planets such atmospheres are diffused, is as yet not satisfactorily determined. The former rests principally upon phenomena observed on the planets’ discs, whilst the latter derives its support chiefly from those detected at or near their respective limbs. Every night, nay almost every hour, may give us indication of the one, whilst years are sometimes necessary, as in the case of planets unattended by satellites, to help us to the other; thus the hypothesis of the extensive atmosphere of Mars derives its origin from the observations of Cassini and Roëmer, and has stood more than a century and a half without refutation or support. The observations to which I allude formed part of a series undertaken for the determination of the parallax of Mars, and are recorded in the Mémoires de l’Académie des Sciences. Cassini’s were made at Briare and at La Charité sur Loire; whilst Roémer’s was obtained at the Royal Observatory of Paris.

Serological characteristics of Streptomyces species using cell wall immunizing antigens

1970 ◽  
Vol 16 (2) ◽  
pp. 107-115 ◽  
Author(s):  
Gerald R. Taylor ◽  
Rufus K. Guthrie ◽  
Elwood B. Shirling
Keyword(s):  
Cell Wall ◽  
Morphological Characteristics ◽  
The Other ◽  
Streptomyces Species ◽  
Dichotomous Key ◽  
Specific Antisera ◽  
Combination Of Methods ◽  
The One ◽  
Taxonomic Studies

A dichotomous key for determination of serological groups among Streptomyces is described. This key is limited in that only seven specific antisera are used for testing. The utility and reliability of the application of this key were tested and compared to the results of previous taxonomic studies reported on the basis of biochemical and morphological characteristics of these organisms. Results indicate the desirability of using a combination of methods including serological characteristics on the one hand, and biochemical–morphological characteristics on the other, to increase the reliability of taxonomic studies.

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