George Gabriel Stokes as a biologist

2020 ◽  
Vol 378 (2179) ◽  
pp. 20200105
Author(s):  
Rhodri Ceredig
Keyword(s):  
Biological Knowledge ◽  
Theme Issue ◽  
Experimental Tool ◽  
Experimental Approaches ◽  
Haemoglobin Molecule

It is universally acknowledged that George Gabriel Stokes (1819–1903) was a polymath who made major contributions to the fields of mathematics, chemistry, physics, fluidics and optics. However, his contributions to biology have received far less attention and this brief communication examines two of Stokes' major biological contributions, namely his description of the phenomenon of fluorescence and his studies on the changes in the colour of blood following oxidation and reduction. The paper on fluorescence is discussed because in it, Stokes demonstrates his wide-ranging biological knowledge and because the use of fluorescence is an invaluable experimental tool in biology. It was by developing the experimental approaches and equipment used to investigate fluorescence that Stokes then applied these to other investigations, including that of blood. From what we now know, what Stokes was describing in his paper on blood were the changes in the configuration of the haemoglobin molecule upon the acquisition and release of oxygen. This article is part of the theme issue ‘Stokes at 200 (part 2)'.

scholarly journals Hierarchy and levels: analysing networks to study mechanisms in molecular biology

2020 ◽  
Vol 375 (1796) ◽  
pp. 20190320 ◽  
Author(s):  
William Bechtel
Keyword(s):  
Biological Networks ◽  
Large Scale ◽  
Biological Knowledge ◽  
Theme Issue ◽  
Epistatic Interactions ◽  
Philosophical Foundations ◽  
High Throughput Data ◽  
Cell Components ◽  
Large Scale Networks ◽  
Network Studies

Network representations are flat while mechanisms are organized into a hierarchy of levels, suggesting that the two are fundamentally opposed. I challenge this opposition by focusing on two aspects of the ways in which large-scale networks constructed from high-throughput data are analysed in systems biology: identifying clusters of nodes that operate as modules or mechanisms and using bio-ontologies such as gene ontology (GO) to annotate nodes with information about where entities appear in cells and the biological functions in which they participate. Of particular importance, GO organizes biological knowledge about cell components and functions hierarchically. I illustrate how this supports mechanistic interpretation of networks with two examples of network studies, one using epistatic interactions among genes to identify mechanisms and their parts and the other using deep learning to predict phenotypes. As illustrated in these examples, when network research draws upon hierarchical information such as provided by GO, the results not only can be interpreted mechanistically but provide new mechanistic knowledge. This article is part of the theme issue ‘Unifying the essential concepts of biological networks: biological insights and philosophical foundations’.

Dynamic Visual Noise Affects Visual Short-Term Memory for Surface Color, but not Spatial Location

2010 ◽  
Vol 57 (1) ◽  
pp. 17-26 ◽  
Author(s):  
Kevin Dent
Keyword(s):  
Short Term Memory ◽  
Spatial Location ◽  
Visual Noise ◽  
Dynamic Visual Noise ◽  
Short Term ◽  
Surface Color ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
Experimental Tool ◽  
Spatial Locations

In two experiments participants retained a single color or a set of four spatial locations in memory. During a 5 s retention interval participants viewed either flickering dynamic visual noise or a static matrix pattern. In Experiment 1 memory was assessed using a recognition procedure, in which participants indicated if a particular test stimulus matched the memorized stimulus or not. In Experiment 2 participants attempted to either reproduce the locations or they picked the color from a whole range of possibilities. Both experiments revealed effects of dynamic visual noise (DVN) on memory for colors but not for locations. The implications of the results for theories of working memory and the methodological prospects for DVN as an experimental tool are discussed.

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

The LIL facility: An experimental tool for laser-matter interaction

2006 ◽  
Vol 133 ◽  
pp. 727-730 ◽  
Author(s):  
P. Eyharts ◽  
J. M. Di-Nicola ◽  
C. Féral ◽  
E. Germain ◽  
H. Graillot ◽  
...  
Keyword(s):  
Experimental Tool ◽  
Matter Interaction

Nuklearmedizin trifft Strahlentherapie

2010 ◽  
Vol 49 (S 01) ◽  
pp. S11-S15
Author(s):  
C. Schütze ◽  
M. Krause ◽  
A. Yaromina ◽  
D. Zips ◽  
M. Baumann
Keyword(s):  
Nuclear Medicine ◽  
Radiation Oncology ◽  
External Beam Radiotherapy ◽  
Biological Knowledge ◽  
Important Research ◽  
Tumour Control ◽  
Research Areas ◽  
Normal Tissue Damage ◽  
Local Tumour Control ◽  
Local Tumour

SummaryRadiobiological and cell biological knowledge is increasingly used to further improve local tumour control or to reduce normal tissue damage after radiotherapy. Important research areas are evolving which need to be addressed jointly by nuclear medicine and radiation oncology. For this differences of the biological distribution of diagnostic and therapeutic nuclides compared with the more homogenous dose-distribution of external beam radiotherapy have to be taken into consideration. Examples for interdisciplinary biology-based cancer research in radiation oncology and nuclear medicine include bioimaging of radiobiological parameters characterizing radioresistance, bioimage-guided adaptive radiotherapy, and the combination of radiotherapy with molecular targeted drugs.

EXPERIMENTAL APPROACHES TO INVESTIGATING LIQUEFIED LPG SPRAY CHARACTERISTICS

2010 ◽  
Vol 20 (6) ◽  
pp. 553-564 ◽  
Author(s):  
Kwan-Soo Lee ◽  
Ki-Hyung Lee ◽  
Ki-Bum Kim ◽  
Yung-Jin Kim
Keyword(s):  
Spray Characteristics ◽  
Experimental Approaches

Ability of Naphthoquinondiazide Photoresists to Exothermic Decomposition

2020 ◽  
pp. 90-96
Author(s):  
A.N. Shushpanov ◽  
◽  
A.Ya. Vasin ◽  
V.M. Raykova ◽  
G.G. Gadzhiev ◽  
...  
Keyword(s):  
Convective Heat Exchange ◽  
Inert Atmosphere ◽  
Necessary Condition ◽  
Critical Temperatures ◽  
Good Convergence ◽  
Measuring Devices ◽  
Explosive Transformation ◽  
Exothermic Decomposition ◽  
Experimental Approaches ◽  
Experimental Values

The article considers two intermediate products of positive photoresists (1,2-naphthoquinonediazide-(2)-5-sulfonic acid of monosodium salt — Dye M and 1,2-naphthoquinonediazide-(2)-5-sulfochloride — Dye N2) from the standpoint of the tendency to explosive transformation. The experimental values of flash points determined on the OTP setup were 130 °C for Dye M and 95 °C for Dye N2. These values are close to the temperatures of the beginning of intensive exothermic decomposition (132 and 111 °C, respectively) obtained by thermogravimetric analysis. In addition, this analysis showed the presence of exothermic peaks in the studied samples both in the air and in an inert atmosphere of helium, which is a necessary condition for the manifestation of a tendency to explosive transformation. To confirm the possibility of explosive transformation, the flash points of substances were also determined by the calculation method according to the formula, which is a consequence of the problem of thermal explosion during convective heat exchange with the environment, and gave a result close to the experimental one (the values were 138 and 105 °C, respectively). For this calculation the following was used: the kinetic parameters determined by the Kissinger method, the values of the density of substances determined on an automatic pycnometer, as well as the values of the heat of explosive transformation obtained with the help of the Real computer thermodynamic program. The research results confirming the tendency of the investigated compounds to explosive transformation, as well as the critical temperatures, exceeding which is unacceptable, were transferred to the production of FGUP GNTs NIOPIK to create a safe technological process, safe storage and transportation conditions. Considering the accuracy of the measuring devices, the process temperature should not exceed 125 °C for Dye M and 90 °C for Dye N2. The conducted studies and calculations show that the computational and experimental approaches have good convergence, give values in a close temperature range, and increase the reliability of the obtained results.

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