Freezing of Cells: Role of Ice and Solutes in Cell Damage

2007 ◽  
Author(s):  
Hiroshi Takamatsu
Keyword(s):  
Mechanical Stress ◽  
Cell Damage ◽  
Cellular Damage ◽  
Elevated Concentration ◽  
Cellular Injury ◽  
Extracellular Solution ◽  
Different Types ◽  
A Cell ◽  
The Difference

The mechanism of cellular damage associated with freezing of biological cells is discussed by summarizing the author’s recent studies that consists of four different types of experiments. The “solution effects” that designate the influence of elevated concentration of electrolytes during freezing is examined first by a nonfreezing experiment that exposes cells to hypertonic solutions using a perfusion microscope. The cell damage due to the solution effect is evaluated directly from a pseudo-freezing experiment, where cells were subjected to the milieu that simulated a freeze-thaw process in the absence of ice. Contribution of ice formed in the extracellular solution is then estimated from the difference in cell survival between the pseudo-freezing experiment and a corresponding freezing experiment. The cellular injury by the mechanical stress is also examined independently by a cell deformation experiment, which mimicked the situation that cells are compressed and deformed between ice crystals. This experiment was designed to examine a complex effect of mechanical stress from ice and elevated concentration of electrolytes. Based on all these experiments, the role of concentrated solutes and ice is revealed as a function of freezing conditions.

scholarly journals MiR-146a in Immunity and Disease

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Nicole Rusca ◽  
Silvia Monticelli
Keyword(s):  
Immune Responses ◽  
Recent Progress ◽  
Viral Infections ◽  
Cellular Functions ◽  
Adaptive Immune Responses ◽  
Adaptive Immune ◽  
Different Types ◽  
A Cell ◽  
And Function

MicroRNAs (miRNAs) are regulatory molecules able to influence all aspects of the biology of a cell. They have been associated with diseases such as cancer, viral infections, and autoimmune diseases, and in recent years, they also emerged as important regulators of immune responses. MiR-146a in particular is rapidly gaining importance as a modulator of differentiation and function of cells of the innate as well as adaptive immunity. Given its importance in regulating key cellular functions, it is not surprising that miR-146a expression was also found dysregulated in different types of tumors. In this paper, we summarize recent progress in understanding the role of miR-146a in innate and adaptive immune responses, as well as in disease.

Different Types of Business-to-Business Integration

2011 ◽  
pp. 1-17
Author(s):  
Frank Goethals ◽  
Jacques Vandenbulcke ◽  
Wilfried Lemahieu
Keyword(s):  
Web Services ◽  
Extended Enterprise ◽  
Enterprise Integration ◽  
Different Types ◽  
The Difference ◽  
Business To Business

In this chapter we argue that there exist two basic forms of business-to-business integration (B2Bi), namely extended enterprise integration and market B2Bi. This chapter clarifies the meaning of both concepts, shows that the difference between both is fundamental, and discusses the consequences of the difference in the realm of Web services development. The importance of coordination and the role of standards are studied for both types of e-business. The authors hope this chapter clearly shows the foundations of B2Bi and that the chapter as such brings clarity into B2Bi practices.

scholarly journals An Analysis of Differences in the Role of Friendships and the School Class in Children’s Perceptions of Bullying in England and Ijime in Japan: A Translation and Expansion of Kanetsuna (2009)

2021 ◽  
Vol 18 (15) ◽  
pp. 8234
Author(s):  
Tomoyuki Kanetsuna ◽  
Peter K. Smith
Keyword(s):  
Secondary School ◽  
Comparative Study ◽  
English Translation ◽  
School Class ◽  
Friendship Formation ◽  
Different Types ◽  
The Difference ◽  
Perceptions Of Bullying ◽  
The Impact

This is an English translation with some expansion of the article originally published in Japanese as a university bulletin in 2009. Previous research has found both differences and similarities between ijime in Japan and bullying in England. Bullying is often by pupils in different classes or higher year groups whom the victim does not know very well; ijime is often by victims’ classmates whom the victim knows very well. However, it has not been shown whether these differences are found for all types of bullying, or how they relate to friendships generally and the impact of differing school systems. We aimed to see whether previously found differences between ijime and bullying could be replicated, and, if so, whether they held for six different types of victimization, and whether friendship characteristics were consistent with explaining why they occur. To investigate the role of friendships and their location, 1036 Japanese and 931 English secondary school pupils participated in a comparative study of perceptions of bullying and ijime. The previous differences were confirmed and found to hold irrespective of type of bullying. Japanese pupils mainly formed friendships on a class basis, English pupils on a broader basis including pupils in different years. In school, English pupils spent much time in the playground with their friends and saw this as a likely venue for bullying, whereas Japanese pupils spent more time in the classroom and saw this as a likely venue for ijime. The difference in friendship formation, together with differences in the organization of class-based teaching in the two countries, are hypothesized to play a significant role in explaining some differences between bullying and ijime.

Guides on the side? Tasks and challenges for teachers in telecollaborative projects

ReCALL ◽  
2004 ◽  
Vol 16 (1) ◽  
pp. 5-19 ◽  
Author(s):  
ROBERT O'DOWD ◽  
KATRIN EBERBACH
Keyword(s):  
Language Learning ◽  
Language Learners ◽  
Review Of The Literature ◽  
Intercultural Learning ◽  
Message Boards ◽  
Good Working ◽  
Different Types ◽  
On Line ◽  
The Difference

This paper reports on research carried out on an intercultural telecollaborative exchange between language learners in Germany and Ireland and focuses particularly on what was required of the teachers in the development of the project. The review of the literature looks at the role of telecollaboration within the field of network-based language learning and also offers an overview of the different types of interaction which have been identified on on-line message boards. Following that, the different tasks of the teachers in the German-Irish exchange are explored. These include developing learners’ understanding of intercultural learning, improving learners’ ability to make effective contributions to the on-line interaction, increasing their awareness of the difference between on-line monologues and dialogues and finally, establishing a good working relationship with the partner teacher. Based on these findings, recommendations are outlined on how to prepare teachers for telecollaborative projects.

Different Types of Business-to-Business Integration

2011 ◽  
pp. 137-151
Author(s):  
Frank Goethals ◽  
Jacgues Vandenbulcke ◽  
Wilfried Lemahieu ◽  
Monique Snoeck
Keyword(s):  
Web Services ◽  
Extended Enterprise ◽  
Enterprise Integration ◽  
Different Types ◽  
The Difference ◽  
Business To Business

In this chapter we argue that there exist two basic forms of business-to-business integration (B2Bi), namely extended enterprise integration and market B2Bi. This chapter clarifies the meaning of both concepts, shows that the difference between both is fundamental, and discusses the consequences of the difference in the realm of Web services development. The importance of coordination and the role of standards are studied for both types of e-business. The authors hope this chapter clearly shows the foundations of B2Bi and that the chapter as such brings clarity into B2Bi practices.

scholarly journals Mathematical model for biological cell deformation in a cylindrical pore

2012 ◽  
Vol 33 (3) ◽  
pp. 385-396 ◽  
Author(s):  
Maciej Szwast ◽  
Teresa Suchecka ◽  
Wojciech Piątkiewicz
Keyword(s):  
Mathematical Model ◽  
Blood Cell ◽  
Mechanical Stress ◽  
Red Blood Cell ◽  
Porous Membrane ◽  
Cylindrical Pore ◽  
Different Types ◽  
Cylindrical Holes ◽  
A Cell ◽  
The Mathematical Model

Abstract Some studies show that cells are able to penetrate through pores that are smaller than cell size. It concerns especially Red Blood Cells but it also may concern different types of biological cells. Such penetration of small pores is a very significant problem in the filtration process, for example in micro- or ultrafiltration. Deformability of cells allows them to go through the porous membrane and contaminate permeate. This paper shows how cells can penetrate small cylindrical holes and tries to assess mechanical stress in a cell during this process. A new mathematical approach to this phenomenon was presented, based on assumptions that were made during the microscopic observation of Red Blood Cell aspiration into a small capillary. The computational model concerns Red Blood Cell geometry. The mathematical model allows to obtain geometrical relation as well as mechanical stress relations.

4. Asking Questions

2017 ◽  
Author(s):  
Sandra Halperin ◽  
Oliver Heath
Keyword(s):  
Research Question ◽  
Research Process ◽  
The Other ◽  
General Question ◽  
Different Types ◽  
Asking Questions ◽  
Research Questions ◽  
The Difference ◽  
The One

This chapter deals with the first step of the research process: the formulation of a well-crafted research question. It explains why political research should begin with a research question and how a research question structures the research process. It discusses the difference between a topic or general question, on the one hand, and a focused research question, on the other. It also considers the question of where to find and how to formulate research questions, the various types of questions scholars ask, and the role of the ‘literature review’ as a source and rationale for research questions. Finally, it describes a tool called the ‘research vase’ that provides a visualization of the research process, along with different types of questions: descriptive question, explanatory question, predictive question, prescriptive question and normative question.

Visual figure–ground discrimination in the honeybee: the role of motion parallax at boundaries

1990 ◽  
Vol 238 (1293) ◽  
pp. 331-350 ◽  
Keyword(s):  
Apparent Motion ◽  
Motion Parallax ◽  
The Other ◽  
Neural Models ◽  
Height Difference ◽  
Sugar Water ◽  
Different Types ◽  
Series Of Experiments ◽  
The Difference

Free flying bees were trained to collect a reward of sugar-water from a structured figure, placed at a randomly varying location on a sheet of transparent Perspex, positioned 5 cm above a structured Background. During subsequent tests, done in the absence of a reward, the bees’ landings on the boundaries of the figure, as well as within the figure and outside it, were recorded. The same bees were also tested with the figure placed directly on the background, thus eliminating the difference in height between the figure and the background. The results of both types of tests were then compared to identify and investigate the cues that bees use to detect a structured figure, when presented over a structured background. The structure of both the figure and the background were varied in a series of experiments, training a fresh group of bees in each experiment. A randomly structured figure presented against a randomly structured background cannot be detected by the bees unless it is raised above the background. A height difference of 2 cm is sufficient to elicit a rate of landings on the figure that is significantly higher than the chance level. The detectability of the figure does not depend upon the shape of the figure or on differences in density between the structures of the figure and the background. Thus, in detecting the raised figure, the only cue used by the bees appears to be the apparent motion of the figure relative to the background. The majority of landings on a raised figure occur at its boundaries. This shows that the visual stimulus that is crucial in detecting the figure is the local discontinuity in apparent motion that occurs at the boundary. We refer to this as ‘boundary parallax ’. In a series of experiments that used a striped background and a variety of structured figures, three different types of boundary parallax were offered to the bees. These were: (i) ‘covering parallax’, at a boundary in which stripes on either side of the boundary are parallel to the boundary; (ii) ‘shearing parallax’, in which stripes on either side are perpendicular to the boundary and (iii) ‘orthogonal parallax’, in which the stripes on one side are perpendicular to those on the other side. The bees performed very well at detecting raised boundaries that offered covering or shearing parallax, despite the fact that such boundaries are not readily discernible on the basis of their static geometry. On the other hand, bees performed poorly in detecting raised boundaries that offered orthogonal parallax, despite the fact that such boundaries are geometrically quite vivid to the human eye. We propose two neural models for the detection of boundary parallax that account for the sensitivity of bees to covering and shearing parallax and their insensitivity to orthogonal parallax.

Unravelling how adjuvants work, and what their roles are in vaccination and allergy

Impact ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. 44-46
Author(s):  
Etsushi Kuroda
Keyword(s):  
Immune System ◽  
Allergic Inflammation ◽  
Adaptive Immune System ◽  
Adaptive Immune ◽  
Different Types ◽  
Pros And Cons ◽  
Disease Agent ◽  
The Difference ◽  
Excessive Activation

The development of safe and effective vaccines is essential to tackling a variety of infectious diseases. Vaccines fall into a variety of different types, depending on how they are produced. The inclusions of live attenuated, inactivated, toxoid, subunit or conjugate vaccines contain key antigens which are used in the vaccines to encourage the immune system to mount an immune response. This response will eventually trigger the creation of targeted memory B cells that persist and can quickly multiple and tackle future interactions with the disease agent. This is the cornerstone of our adaptive immune system, protecting us against getting many diseases more than once. Vaccines often contain more than just the antigen. They also commonly contain a facilitating agent known as an adjuvant. Adjuvants enhance the effect of the vaccine, making it more likely to work and to work well, however, it has long been thought that they themselves confer no immunity if presented to the immune system without the antigen. One of the biggest mysteries in immunology is how exactly adjuvants function. They certainly do function, often making the difference between an ineffectual vaccine and one that can help tackle a disease. However, answering the question of 'how?' may well prove key to the development of better vaccines and even treatments in other fields of human disease. Investigating the mode of action of adjuvants is Dr Etsushi Kuroda, Senior Researcher at NIBIOHN, Japan. He works in the Center for Vaccine and Adjuvant Research under Dr Ken J. Ishii in a large lab with multiple researchers focussing on a different aspect of adjuvants. Kuroda's field of interest is the role of pollution particulates as adjuvants to allergy and asthma. Kuroda explains his area of research in greater detail: 'Particle pollutants that we focused on are also thought to be adjuvants and induce inflammation when they are inhaled. There are pros and cons in adjuvants, and excessive activation of immune cells by adjuvant might induce immune-related diseases such as allergic inflammation.'

scholarly journals Laccase Protects Cryptococcus neoformansfrom Antifungal Activity of Alveolar Macrophages

1999 ◽  
Vol 67 (11) ◽  
pp. 6034-6039 ◽  
Author(s):  
Lide Liu ◽  
Ram P. Tewari ◽  
Peter R. Williamson
Keyword(s):  
Antifungal Activity ◽  
Hydroxyl Radical ◽  
Oxidase Activity ◽  
Radical Scavenger ◽  
Free System ◽  
Recombinant Laccase ◽  
Hydroxyl Radical Scavenger ◽  
A Cell ◽  
The Difference

ABSTRACT While laccase of Cryptococcus neoformans is implicated in the virulence of the organism, our recent studies showing absence of melanin in the infected mouse brain has led us to a search for alternative roles for laccase in cryptococcosis. We investigated the role of laccase in protection of C. neoformans against murine alveolar macrophage (AM)-mediated antifungal activity by using a pair of congenic laccase-positive (2E-TUC) and laccase-deficient (2E-TU) strains. The laccase-positive cells with laccase derepression were more resistant to the antifungal activity of AM than a laccase-deficient strain ([28.9 ± 1.2]% versus [40.2 ± 2.6]% killing). Addition of l-dopa toCryptococcus to produce melanin in a laccase-positive strain resulted in a slight increase in protection of C. neoformans from the antifungal activity of macrophages ([25.4 ± 3.4]% versus [28.9 ± 1.2]% killing). Recombinant cryptococcal laccase exhibited iron oxidase activity in converting Fe(II) to Fe(III). Moreover, recombinant laccase inhibited killing of C. neoformans by hydroxyl radicals catalyzed by iron in a cell-free system. Addition of the hydroxyl radical scavenger mannitol or dimethyl sulfoxide to AMs prior to the introduction of cryptococcal cells decreased killing of both strains and reduced the difference in susceptibility between the laccase-positive and laccase-deficient strains. Furthermore, laccase-mediated protection from AM killing was inhibited by the addition of Fe(II), presumably by overcoming the effects of the iron oxidase activity of cryptococcal laccase. These results suggest that the iron oxidase activity of laccase may protect C. neoformans from macrophages by oxidation of phagosomal iron to Fe(III) with a resultant decrease in hydroxyl radical formation.

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