scholarly journals Tailoring hydrogel microstructure via phase separation and kinetic trapping

2021 ◽  
Author(s):  
Simon Vieth
Keyword(s):  
Phase Separation ◽  
Drug Release ◽  
Controlled Drug Release ◽  
Continuous Phase ◽  
The Other ◽  
Phase Iii ◽  
Droplet Growth ◽  
Aqueous Mixtures ◽  
Kinetic Trapping ◽  
Over Time

Control of the microstructure of a biopolymeric phase-separated system is presented as part of an effort to develop a novel platform for controlled drug release. Under certain conditions, aqueous mixtures of biopolymers exhibit thermodynamic incompatibility and separate into distinct phases, each concentrated in one component and poor in the other. Upon initiation of phase separation (PS), droplets of one phase, the included phase, appear and ripen over time such that shared surface area with the continuous phase is minimized. Gelation is a means of halting droplet growth prior to bulk PS (BPS). The purpose of this research is to establish the means to dictate the microstructure of a PS system by: (i) understanding the effects of biopolymer concentration on PS temperature, TPS; (ii) modeling the growth of droplets within the included-phase; (iii) examining the efficacy of gelation as a means of trapping microstructure and (iv) investigating the characteristic microstructures of biopolymer systems undergoing a two-step temperature quench.

scholarly journals Tailoring hydrogel microstructure via phase separation and kinetic trapping

2021 ◽  
Author(s):  
Simon Vieth
Keyword(s):  
Phase Separation ◽  
Drug Release ◽  
Controlled Drug Release ◽  
Continuous Phase ◽  
The Other ◽  
Phase Iii ◽  
Droplet Growth ◽  
Aqueous Mixtures ◽  
Kinetic Trapping ◽  
Over Time

Control of the microstructure of a biopolymeric phase-separated system is presented as part of an effort to develop a novel platform for controlled drug release. Under certain conditions, aqueous mixtures of biopolymers exhibit thermodynamic incompatibility and separate into distinct phases, each concentrated in one component and poor in the other. Upon initiation of phase separation (PS), droplets of one phase, the included phase, appear and ripen over time such that shared surface area with the continuous phase is minimized. Gelation is a means of halting droplet growth prior to bulk PS (BPS). The purpose of this research is to establish the means to dictate the microstructure of a PS system by: (i) understanding the effects of biopolymer concentration on PS temperature, TPS; (ii) modeling the growth of droplets within the included-phase; (iii) examining the efficacy of gelation as a means of trapping microstructure and (iv) investigating the characteristic microstructures of biopolymer systems undergoing a two-step temperature quench.

scholarly journals Stealth Magnetoliposomes Based on Calcium-Substituted Magnesium Ferrite Nanoparticles for Curcumin Transport and Release

2020 ◽  
Vol 21 (10) ◽  
pp. 3641 ◽  
Author(s):  
Beatriz D. Cardoso ◽  
Ana Rita O. Rodrigues ◽  
Bernardo G. Almeida ◽  
Carlos O. Amorim ◽  
Vítor S. Amaral ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Drug Release ◽  
Natural Compound ◽  
Controlled Drug Release ◽  
Magnetic Hyperthermia ◽  
Ferrite Nanoparticles ◽  
Pharmacological Properties ◽  
Magnesium Ferrite ◽  
Superparamagnetic Properties ◽  
Over Time

Despite the promising pharmacological properties of curcumin, the transport and effective release of curcumin is still a challenge. The advances in functionalized nanocarriers for curcumin have also been motivated by the anticancer activity of this natural compound, aiming at targeted therapies. Here, stealth (aqueous and solid) magnetoliposomes containing calcium-substituted magnesium ferrite nanoparticles, CaxMg1−xFe2O4 (with x = 0.25, 0.50, 0.75) were developed as nanocarriers for curcumin. The magnetic nanoparticles exhibit superparamagnetic properties and crystalline structure, with sizes below 10 nm. The magnetoliposomes based on these nanoparticles have hydrodynamic diameters around or below 150 nm and a low polydispersity. The influence of an alternating magnetic field (AMF) on drug release over time was evaluated and compared with curcumin release by diffusion. The results suggest the potential of drug-loaded magnetoliposomes as nanocarriers that can be magnetically guided to the tumor sites and act as agents for a synergistic effect combining magnetic hyperthermia and controlled drug release.

Structure evolution during phase separation in spin-coated ethylcellulose/hydroxypropylcellulose films

Soft Matter ◽  
2021 ◽  
Author(s):  
Pierre Carmona ◽  
Magnus Röding ◽  
Aila Särkkä ◽  
Christian von Corswant ◽  
Eva Olsson ◽  
...  
Keyword(s):  
Phase Separation ◽  
Drug Release ◽  
Film Thickness ◽  
Spin Coating ◽  
Good Control ◽  
Controlled Drug Release ◽  
Structure Evolution ◽  
Length Scale ◽  
Method Optimization

Porous phase-separated films made of ethylcellulose (EC) and hydroxypropylcellulose (HPC) for controlled drug release were made using spin-coating. The method optimization gave good control over the film thickness and the length scale.

Emotional Impact Feedback Changes How We Remember Negative Autobiographical Experiences

2010 ◽  
Vol 57 (5) ◽  
pp. 354-359 ◽  
Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange
Keyword(s):  
Well Being ◽  
The Other ◽  
Personal Perspective ◽  
Emotional Impact ◽  
Potential Mechanism ◽  
Negative Experiences ◽  
Negative Memory ◽  
The Relationship ◽  
Negative Memories ◽  
Over Time

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.

Coevolution

2017 ◽  
Author(s):  
Avi Max Spiegel
Keyword(s):  
The Other ◽  
The Political ◽  
Over Time ◽  
Islamist Movements

This chapter seeks to understand how Islamist movements have evolved over time, and, in the process, provide important background on the political and religious contexts of the movements in question. In particular, it shows that Islamist movements coevolve. Focusing on the histories of Morocco's two main Islamist movements—the Justice and Spirituality Organization, or Al Adl wal Ihsan (Al Adl) and the Party of Justice and Development (PJD)—it suggests that their evolutions can only be fully appreciated if they are relayed in unison. These movements mirror one another depending on the competitive context, sometimes reflecting, sometimes refracting, sometimes borrowing, sometimes adapting or even reorganizing in order to keep up with the other.

Correspondances étymologiques, lexicales et sémantiques dans le processus de féminisation de noms de profession, métiers et activités dans les sociétés française et roumaine

2020 ◽  
Vol 65 (4) ◽  
pp. 401-422
Author(s):  
Estelle Variot
Keyword(s):  
The Other ◽  
Roman World ◽  
Other Hand ◽  
The One ◽  
Over Time

"Etymological, Lexical and Semantic Correspondences in the Process of Feminization of Professional Names, Trades and Activities in French and Romanian Societies. The feminization of thought represented by language and of its varieties in the Roman World has allowed to highlight some convergences that come from a common linguistic heritage, often from Greek and Latin and some hesitation about adapting society to its realities. The feminization of some words which comes from an ancient process illustrates on the one hand the potential of the language and on the other hand some constraints sometimes linked to the society itself, which creates transitional periods, between matching grammatical correction and the evolution of linguistic uses over time. The possibilities of lexical enrichment (internal creation or loan) show the means available in French and Romanian and some convergences in the area of derivation, of lexical units and their etymologies. The grammatical perspective and word constructing methods make it possible to give keys for the feminization of names of trades or professions. Likewise, recording entries in the lexicon, their evolution, their assimilation or sometimes their forgetfulness, for the benefit of new constructions highlight the existence of objective and subjective criteria which teach us a lot about society as a whole. Keywords: feminization of professions, internal and external enrichment, suffixal match, use of words, grammar, lexicon, French and Romanian."

The Values and Norms of Islam

2010 ◽  
Vol 1 (1) ◽  
pp. 1-19
Author(s):  
Ahmed Akgunduz
Keyword(s):  
Islamic Law ◽  
Legal Theory ◽  
The Other ◽  
Moral Norms ◽  
Simple Fact ◽  
Value System ◽  
Legal Norms ◽  
Islamic Legal Theory ◽  
The World ◽  
Over Time

AbstractIslamic Law is one of the broadest and most comprehensive systems of legislation in the world. It was applied, through various schools of thought, from one end of the Muslim world to the other. It also had a great impact on other nations and cultures. We will focus in this article on values and norms in Islamic law. The value system of Islam is immutable and does not tolerate change over time for the simple fact that human nature does not change. The basic values and needs (which can be called maṣlaḥa) are classified hierarchically into three levels: (1) necessities (Ḍarūriyyāt), (2) convenience (Ḥājiyyāt), and (3) refinements (Kamāliyyāt=Taḥsīniyyāt). In Islamic legal theory (Uṣūl al‐fiqh) the general aim of legislation is to realize values through protecting and guaranteeing their necessities (al-Ḍarūriyyāt) as well as stressing their importance (al‐ Ḥājiyyāt) and their refinements (taḥsīniyyāt).In the second part of this article we will draw attention to Islamic norms. Islam has paid great attention to norms that protect basic values. We cannot explain all the Islamic norms that relate to basic values, but we will classify them categorically. We will focus on four kinds of norms: 1) norms (rules) concerned with belief (I’tiqādiyyāt), 2) norms (rules) concerned with law (ʿAmaliyyāt); 3) general legal norms (Qawā‘id al‐ Kulliyya al‐Fiqhiyya); 4) norms (rules) concerned with ethics (Wijdāniyyāt = Aḵlāqiyyāt = Ādāb = social and moral norms).

Fostering Collaborative Autonomy: The Roles of Cooperative and Collaborative Learning

Relay Journal ◽  
2018 ◽  
pp. 360-381
Author(s):  
Gordon Myskow ◽  
Phillip A. Bennett ◽  
Hisako Yoshimura ◽  
Kyoko Gruendel ◽  
Takuto Marutani ◽  
...  
Keyword(s):  
Collaborative Learning ◽  
Cooperative Learning ◽  
Learner Autonomy ◽  
The Other ◽  
Learning Activities ◽  
Educational Context ◽  
Learning Approaches ◽  
Group Interactions ◽  
Collaborative Autonomy ◽  
Over Time

The distinction between Cooperative and Collaborative Learning approaches is not a clear one. Some use the terms interchangeably while others consider Cooperative Learning to be a type of Collaborative Learning. Still others clearly differentiate between them, characterizing Cooperative Learning as more highly structured in its procedures, involving a great deal of intervention by the teacher to plan and orchestrate group interactions. Collaborative Learning, on the other hand, presupposes some degree of learner autonomy－that groups can work effectively toward shared goals and monitor their own progress. This paper takes the view that the distinction between Cooperative and Collaborative Learning is a useful one and that both approaches can play valuable roles in fostering autonomous interaction. It argues that while Collaborative Learning formations may be the ultimate goal for teachers wishing to develop learner autonomy, Cooperative Learning is a valuable means for modeling the skills and abilities to help students get there. The discussion begins with an overview of the two approaches, focusing on their implementation in the Japanese educational context. It then presents seven highly structured Cooperative Learning activities and shows how they can be modified and extended over time to encourage more autonomous interaction.

Reducing the Risk in Controlled Drug Release by Using Tannic Acid in Liposomal Formulations

2018 ◽  
Vol 68 (12) ◽  
pp. 2925-2918
Author(s):  
Gabriela Cioca ◽  
Maricel Agop ◽  
Marcel Popa ◽  
Simona Bungau ◽  
Irina Butuc
Keyword(s):  
Drug Release ◽  
Tannic Acid ◽  
Release Rate ◽  
Controlled Drug Release ◽  
Toxicity Threshold ◽  
Release System ◽  
Liposomal Formulations ◽  
Cross Linker ◽  
Natural Cross

One of the main challenges in designing a release system is the possibility to control the release rate in order to maintain it at a constant value below a defined limit, to avoid exceeding the toxicity threshold. We propose a method of overcoming this difficulty by introducing the drug into liposomes, prior to its inclusion in the hydrogel. Furthermore, a natural cross linker (as is tannic acid) is used, instead of the toxic cross linkers commonly used, thus reducing the toxicity of the release system as a whole.

Sign in / Sign up

Export Citation Format

Share Document