scholarly journals The Effects of Three-Dimensional Ligand Immobilization on Kinetic Measurements in Biosensors

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 241
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Monireh Bakhshpour ◽  
Nese Lortlar Ünlü ◽  
M. Selim Ünlü

The field of biosensing is in constant evolution, propelled by the need for sensitive, reliable platforms that provide consistent results, especially in the drug development industry, where small molecule characterization is of uttermost relevance. Kinetic characterization of small biochemicals is particularly challenging, and has required sensor developers to find solutions to compensate for the lack of sensitivity of their instruments. In this regard, surface chemistry plays a crucial role. The ligands need to be efficiently immobilized on the sensor surface, and probe distribution, maintenance of their native structure and efficient diffusion of the analyte to the surface need to be optimized. In order to enhance the signal generated by low molecular weight targets, surface plasmon resonance sensors utilize a high density of probes on the surface by employing a thick dextran matrix, resulting in a three-dimensional, multilayer distribution of molecules. Despite increasing the binding signal, this method can generate artifacts, due to the diffusion dependence of surface binding, affecting the accuracy of measured affinity constants. On the other hand, when working with planar surface chemistries, an incredibly high sensitivity is required for low molecular weight analytes, and furthermore the standard method for immobilizing single layers of molecules based on self-assembled monolayers (SAM) of epoxysilane has been demonstrated to promote protein denaturation, thus being far from ideal. Here, we will give a concise overview of the impact of tridimensional immobilization of ligands on label-free biosensors, mostly focusing on the effect of diffusion on binding affinity constants measurements. We will comment on how multilayering of probes is certainly useful in terms of increasing the sensitivity of the sensor, but can cause steric hindrance, mass transport and other diffusion effects. On the other hand, probe monolayers on epoxysilane chemistries do not undergo diffusion effect but rather other artifacts can occur due to probe distortion. Finally, a combination of tridimensional polymeric chemistry and probe monolayer is presented and reviewed, showing advantages and disadvantages over the other two approaches.

2015 ◽  
Vol 40 (3) ◽  
pp. 467-473
Author(s):  
P. Masłowski ◽  
J. Gniot-Sulżycka ◽  
G. Rześniowiecka

Treatment of maize seedes with GA3 increased the content of water, the phosphate acid soluble fraction, the phospholipid fraction and the low molecular weight r-RNA, s-RNA, DNA-RNA fractions in 5-days-old seedlings. On the other hand, the contents of RNA and DNA in such seedlings decreased.


Author(s):  
Oscar Gutiérrez-Bolívar ◽  
Oscar Gutiérrez-Bolívar ◽  
Pedro Fernández Carrasco ◽  
Pedro Fernández Carrasco

The opening of relationships between United States and Cuba could be a drive for a huge increase in the affluence of tourism to Cuba and especially to the coast areas. Cuba has been for many years an important tourist destination for people from many countries, but almost forbidden for US citizens. The proximity of the USA, its amount of population as well as their great acquisition power will increase in a very substantial way the demand for accommodation and other uses in the proximity of the coasts. There will be a need to implement a package of measures that reduce the impact of such sudden increase in the coastal line. On the other hand that augment in tourism could be an opportunity to improve the standard of life of Cubans. The consideration of different possibilities of such development, the analysis of the damages that each one could cause as well as the measures that could avoid, ameliorate or compensate such effects are the goals that are going to be presented in this paper.


Author(s):  
Anna Peterson

This book examines the impact that Athenian Old Comedy had on Greek writers of the Imperial era. It is generally acknowledged that Imperial-era Greeks responded to Athenian Old Comedy in one of two ways: either as a treasure trove of Atticisms, or as a genre defined by and repudiated for its aggressive humor. Worthy of further consideration, however, is how both approaches, and particularly the latter one that relegated Old Comedy to the fringes of the literary canon, led authors to engage with the ironic and self-reflexive humor of Aristophanes, Eupolis, and Cratinus. Authors ranging from serious moralizers (Plutarch and Aelius Aristides) to comic writers in their own right (Lucian, Alciphron), to other figures not often associated with Old Comedy (Libanius) adopted aspects of the genre to negotiate power struggles, facilitate literary and sophistic rivalries, and provide a model for autobiographical writing. To varying degrees, these writers wove recognizable features of the genre (e.g., the parabasis, its agonistic language, the stage biographies of the individual poets) into their writings. The image of Old Comedy that emerges from this time is that of a genre in transition. It was, on the one hand, with the exception of Aristophanes’s extant plays, on the verge of being almost completely lost; on the other hand, its reputation and several of its most characteristic elements were being renegotiated and reinvented.


Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 213
Author(s):  
Hamid Ait Said ◽  
Hassan Noukrati ◽  
Hicham Ben Youcef ◽  
Ayoub Bayoussef ◽  
Hassane Oudadesse ◽  
...  

Three-dimensional hydroxyapatite-chitosan (HA-CS) composites were formulated via solid-liquid technic and freeze-drying. The prepared composites had an apatitic nature, which was demonstrated by X-ray diffraction and Infrared spectroscopy analyses. The impact of the solid/liquid (S/L) ratio and the content and the molecular weight of the polymer on the composite mechanical strength was investigated. An increase in the S/L ratio from 0.5 to 1 resulted in an increase in the compressive strength for HA-CSL (CS low molecular weight: CSL) from 0.08 ± 0.02 to 1.95 ± 0.39 MPa and from 0.3 ± 0.06 to 2.40 ± 0.51 MPa for the HA-CSM (CS medium molecular weight: CSM). Moreover, the increase in the amount (1 to 5 wt%) and the molecular weight of the polymer increased the mechanical strength of the composite. The highest compressive strength value (up to 2.40 ± 0.51 MPa) was obtained for HA-CSM (5 wt% of CS) formulated at an S/L of 1. The dissolution tests of the HA-CS composites confirmed their cohesion and mechanical stability in an aqueous solution. Both polymer and apatite are assumed to work together, giving the synergism needed to make effective cylindrical composites, and could serve as a promising candidate for bone repair in the orthopedic field.


Agriculture ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 542
Author(s):  
Dariusz Kulus ◽  
Natalia Miler

Lamprocapnos spectabilis (L.) Fukuhara (bleeding heart) is valued both in the horticultural and pharmaceutical markets. Despite its great popularity, information on the in vitro tissue culture technology in this species is limited. There is also little knowledge on the application of plant extracts in the tissue culture systems of plants other than orchids. The aim of this study is to compare the utility of traditional plant growth regulators (PGRs) and natural extracts—obtained from the coconut shreds, as well as oat, rice, and sesame seeds—in the micropropagation and cryopreservation of L. spectabilis ‘Gold Heart’ and ‘White Gold’. The biochemical analysis of extracts composition is also included. In the first experiment related to micropropagation via axillary buds activation, the single-node explants were cultured for a 10-week-long propagation cycle in the modified Murashige and Skoog medium fortified either with 1.11 µM benzyladenine (BA) and 1.23 µM indole-3-butritic acid (IBA) or with 10% (v/v) plant extracts. A PGRs- and extract-free control was also considered. In the cryopreservation experiment, the same 10% (v/v) extracts were added into the medium during a seven-day preculture in the encapsulation-vitrification cryopreservation protocol. It was found that the impact of natural additives was cultivar- and trait-specific. In the first experiment, the addition of coconut extract favoured the proliferation of shoots and propagation ratio in bleeding heart ‘Gold Heart’. Rice extract, on the other hand, promoted callus formation in ‘White Gold’ cultivar and was more effective in increasing the propagation ratio in this cultivar than the conventional plant growth regulators (4.1 and 2.6, respectively). Sesame extract suppressed the development of the explants in both cultivars analysed, probably due to the high content of polyphenols. As for the second experiment, the addition of plant extracts into the preculture medium did not increase the survival level of the cryopreserved shoot tips (sesame and oat extracts even decreased this parameter). On the other hand, coconut extract, abundant in simple sugars and endogenous cytokinins, stimulated a more intensive proliferation and growth of shoots after rewarming of samples. Analysing the synergistic effect of conventional plant growth regulators and natural extracts should be considered in future studies related to L. spectabilis.


2012 ◽  
Vol 602-604 ◽  
pp. 776-780
Author(s):  
Zhi Qiang Li ◽  
Mei Li ◽  
Wei Jia Fan

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)copolymer [P(3HB-co-4HB)] is a kind of biodegradable high molecular polymer produced by bioaccumulation. Because of the good biodegradability and biocompatibility, P(3HB-co-4HB)s have attracted wide attention . At first, the intrinsic viscosity[η] in good solvent of P(3HB-co-4HB) s with varying contents of 4HB was investigated in different temperature. Second, observed the changes of crystallization gathered state caused by the varying contents of 4HB by polarizing microscope. The results show that to the P(3HB-co-4HB)s in same molecular weight, the intrinsic viscosity[η] in good solvent barely changes when the mole fractions of 4HB increase. On the other hand, the mean square end to end distances[0] of macromolecular flexible chains increase with the mole fractions of 4HB. At the same time, the states of aggregation change from spherulites to dendrites. In this investigation, we discuss the reasons of the differences in depth.


1981 ◽  
Vol 32 (3) ◽  
pp. 265-283 ◽  
Author(s):  
Nicholas Orme

During the last hundred years our knowledge of the educational institutions of medieval England has steadily increased, both of schools and universities. We know a good deal about what they taught, how they were organised and where they were sited. The next stage is to identify their relationship with the society which they existed to serve. Whom did they train, to what standards and for what ends? These questions pose problems. They cannot be answered from the constitutional and curricular records which tell us about the structure of educational institutions. Instead, they require a knowledge of the people—the pupils and scholars—who went to the medieval schools and universities. We need to recover their names, to compile their biographies and thereby to establish their origins, careers and attainments. If this can be done on a large enough scale, the impact of education on society will become clearer. In the case of the universities, the materials for this task are available and well known. Thanks to the late Dr A. B. Emden, most of the surviving names of the alumni of Oxford and Cambridge have been collected and published, together with a great many biographical records about them. For the schools, on the other hand, where most boys had their literary education if they had one at all, such data are not available. Except for Winchester and Eton, we do not possess lists of the pupils of schools until the middle of the sixteenth century, and there is no way to remedy the deficiency.


2021 ◽  
Vol 13 (20) ◽  
pp. 11193
Author(s):  
Karol Król ◽  
Dariusz Zdonek

Content published in social media (SM) can be motivating. It can induce action, stimulate demand, and shape opinions. On the other hand, it can demotivate, cause helplessness, or overwhelm with information. Still, the impact of SM is not always the same. The paper aims to analyse the relations between sex, personality, and the way social media is used and motivation to take specific actions. The conclusions are founded on a survey (n = 462). The data were analysed with statistical methods. The study revealed that the use of SM has a significant impact on the motivation to act. Browsing through descriptions and photographs of various achievements posted by others in SM increased the intrinsic motivation of the respondents. Positive comments and emojis had a similar effect. Moreover, women and extraverts noted a significantly greater impact of SM on their intrinsic motivation concerning health and beauty effort, travel, hobby, and public expression of opinions than men and introverts. The results can be useful to recruiters. Extravert women that are open to cooperation, thorough, and well-organised are more likely to be active in SM.


2020 ◽  
Vol 7 (2) ◽  
pp. 411-430
Author(s):  
Maja Tabea Jerrentrup

Abstract The art of bodypainting that is fairly unknown to a wider public turns the body into a canvas - it is a frequently used phrase in the field of bodypainting that illustrates the challenge it faces: it uses a three-dimensional surface and has to cope with its irregularities, but also with the model’s abilities and characteristics. This paper looks at individuals who are turned into art by bodypainting. Although body painting can be very challenging for them - they have to expose their bodies and to stand still for a long time while getting transformed - models report that they enjoy both the process and the result, even if they are not confident about their own bodies. Among the reasons there are physical aspects like the sensual enjoyment, but also the feeling of being part of something artistic. This is enhanced and preserved through double staging - becoming a threedimentional work of art and then being staged for photography or film clips. This process gives the model the chance to experience their own body in a detached way. On the one hand, bodypainting closely relates to the body and on the other hand, it can help to over-come the body.


2021 ◽  
Vol 8 (12) ◽  
pp. 374-377
Author(s):  
Prapattra Hongwisat ◽  
Thanawat Wuthikanokkan ◽  
Nathakan Preechakansakul

Covid-19 are one of the viruses that were widely spreaded in 2019 and are still separate until nowadays. Thailand is one of the countries that are highly infected. The majority of people who are infected with this virus tend to have mild to severe respiratory symptoms. Furthermore, anyone can get sick, and it can lead to death. However, the most common symptoms of this virus are fever, cough, tiredness, and loss of taste or smell, on the other hand, characteristics in a minority of people, such as diarrhea and headaches. Due to the impact of the Covid-19 virus, people have to change their lifestyle to the online form. These changes have impacted mostly on economics and education in particular countries, so this problem also affects anxiety among high school students; who must prepare to apply to the university during the COVID-19 outbreak. In addition, we have collected 151 answers from high school students by surveying in order to know the feelings for entrance to the university during the pandemic situation. We found out that 81.3% of the students are highly affected by covid, and only 0.7% of students are slightly affected. We also found out that 55% of the students are worried about university entrance, and only 2.6% of the students were not worried at all. According to the result, most of the students in Thailand are facing the problem about their education and their entrance for the university which are caused by Covid-19. This may lead to illnesses like depression and anxiety. Keywords: Students, Learning, COVID-19, Thailand, University.


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