scholarly journals Arrhenius' theory of partial dissociation and hydration of electrolytes in solutions replaces existing activity concepts

2011 ◽  
Author(s):  
Raji Heyrovska
Keyword(s):  
Arrhenius Theory ◽  
Partial Dissociation

scholarly journals REACTIONS BETWEEN INFLUENZA VIRUS AND A COMPONENT OF ALLANTOIC FLUID

1948 ◽  
Vol 88 (4) ◽  
pp. 463-484 ◽  
Author(s):  
Paul H. Hardy ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Influenza A Virus ◽  
Influenza A ◽  
Allantoic Fluid ◽  
Partial Dissociation

Evidence is presented which shows that there is a component present in normal allantoic fluid, probably mucoprotein in nature, capable of combining with influenza A virus (PR8), and that following combination between this component and the virus only partial dissociation of the complex occurs. Evidence is also presented which strongly suggests that the component is present in virus-infected allantoic fluid in which it is in part combined with the virus and in part free although altered by viral action. The probability that the component is present as well in highly purified preparations of influenza virus, and its effect upon various reactions obtained with this agent are discussed.

The distribution of cytoplasmic bacteria in the early Drosophila embryo is mediated by astral microtubules

1994 ◽  
Vol 107 (3) ◽  
pp. 673-682 ◽  
Author(s):  
G. Callaini ◽  
M.G. Riparbelli ◽  
R. Dallai
Keyword(s):  
Cortical Layer ◽  
Drosophila Embryo ◽  
Mitotic Spindles ◽  
Embryo Viability ◽  
Polar Bodies ◽  
Early Drosophila Embryo ◽  
Close Relationship ◽  
Different Strains ◽  
Partial Dissociation ◽  
Almost All

Maternally inherited cytoplasmic bacteria have occasionally been observed in embryos and adults of different strains of several Drosophila species. While there is a considerable body of data on the relationship between bacteria and embryo viability, little is known about the behavior of these bacteria during the early development of Drosophila. In eggs laid by infected Drosophila melanogaster females we showed that cytoplasmic bacteria were initially concentrated in a thin cortical layer and scattered in the yolk region. During the following syncytial blastoderm mitoses the bacteria mainly accumulated towards the poles of the mitotic spindles, suggesting that astral microtubules play a role in localizing bacteria. This is supported by the observation that treatment of the infected embryos with the microtubule-disrupting drug colchicine led to the partial dissociation of the bacteria from the spindle poles, whereas cytochalasin treatment left almost all the bacterial clusters intact. Moreover, bacteria were not found near the polar bodies and yolk nuclei, which were without astral microtubules. In mitosis-defective embryos, with centrosomes dissociated from the nuclei, the bacteria were concentrated in association with the isolated astral microtubules, and in cold-treated embryos, in which microtubules regrew from isolated centrosomes after recovering, the bacteria clustered around the newly formed asters. These observations, also supported by electron microscope analysis, indicate a close relationship between cytoplasmic bacteria and astral microtubules, and suggest that the latter were able to build discrete cytoplasmic domains ensuring the proper distribution of cytoplasmic components during the blastoderm mitoses, despite the lack of cell membranes.

scholarly journals ELECTRO-OSMOTIC FRACTIONATION OF HYDROGEN ISOTOPES IN ELECTROLYTIC SOLUTIONS USING COMPOSITE PROTON-PERMEABLE MEMBRANES

2021 ◽  
pp. 11-16
Author(s):  
O. Pushkar'ov ◽  
A. Zubko ◽  
I. Sevruk ◽  
V. Dolin
Keyword(s):  
Hydrogen Bonds ◽  
Proton Conductivity ◽  
Tritiated Water ◽  
High Mobility ◽  
Hydrogen Isotopes ◽  
Water Molecules ◽  
Proton Conducting ◽  
Partial Dissociation ◽  
Surface Modified ◽  
Conducting Membranes

Based on the analysis of the features of electroosmotic processes that are implemented in proton-conducting membranes, the possibility of fractioning hydrogen isotopes in electrolytes formed using tritiated water (HTO) is estimated. The interaction of the solution with the membranes in their channels leads to polarization and partial dissociation of the electrolyte molecules. In water molecules, when protium is replaced by a heavy isotope of hydrogen, the energy of breaking of hydrogen bonds increases and the process of their dissociation proceeds predominantly according to the scheme: HTO ↔ H+ + TO—. A part of the released protons can join water molecules to form the H3O+ ion. H3O+ and TO— ions are more mobile than other singly charged ions. The main characteristic that determines the suitability of electroosmotic membranes to the fractionation of hydrogen isotopes is proton conductivity. The released protons have anomalously high mobility due to their small size, tunnel and relay movement through hydrogen bonds between adjacent polar groups in the channels of the proton-conducting membranes. To ensure high proton conductivity in the pores and channels of the membranes, modifying substances are fixed, which contain the groups: –ОН- , –NH2, –NH, –SH, –COOH, –SO3H, acid salts and oxides, containing surface proton-conducting groups. To create proton-conducting membranes, it is possible to use surface-modified β-alumina (β-Al2O3(H3O+)) and protonated (H3O+) montmorillonite with ionic conductivity (5х103 – 4х104 Ohm х cm–1). The most effective are surface modifiers with negatively charged sulfonic groups. The imposition of an external electric field leads to the movement of ions in the electrolyte, which leads to a redistribution of the isotope ratio in the near-anode and cathode spaces.

scholarly journals Rest-task Modulation of fMRI-derived Global Signal Topography is Mediated by Transient Co-activation Patterns

2019 ◽  
Author(s):  
Jianfeng Zhang ◽  
Zirui Huang ◽  
Shankar Tumati ◽  
Georg Northoff
Keyword(s):  
Resting State ◽  
Resting State Fmri ◽  
Peak Period ◽  
Physiological Noise ◽  
Activation Patterns ◽  
Global Signal ◽  
Co Activation ◽  
Human Connectome Project ◽  
Partial Dissociation ◽  
Signal Correlation

AbstractRecent resting-state fMRI studies have revealed that the global signal (GS) exhibits a non-uniform spatial distribution across the gray matter. Whether this topography is informative remains largely unknown. We therefore tested rest-task modulation of global signal topography by analyzing static global signal correlation and dynamic co-activation patterns in a large sample of fMRI dataset (n=837) from the Human Connectome Project. The GS topography in the resting-state and in seven different tasks was first measured by correlating the global signal with the local timeseries (GSCORR). In the resting state, high GSCORR was observed mainly in the primary sensory and motor regions, while low GSCORR was seen in the association brain areas. This pattern changed during the seven tasks, with mainly decreased GSCORR in sensorimotor cortex. Importantly, this rest-task modulation of GSCORR could be traced to transient co-activation patterns at the peak period of global signal (GS-peak). By comparing the topography of GSCORR and respiration effects, we observed that the topography of respiration mimicked the topography of global signal in the resting-state whereas both differed during the task states; due to such partial dissociation, we assume that GSCORR could not be equated with a respiration effect. Finally, rest-task modulation of GS topography could not be exclusively explained by other sources of physiological noise. Together, we here demonstrate the informative nature of global signal topography by showing its rest-task modulation, the underlying dynamic co-activation patterns, and its partial dissociation from respiration effects during task states.

scholarly journals DEET Degradation by Titanium Dioxide–Zeolite Nanocomposites: Effects of Aggregation State, Water Chemistry, and Natural Organic Matter

2020 ◽  
Author(s):  
Tchemongo B. Berté ◽  
Anthony S. Chen ◽  
Riya A. Mathew ◽  
Sheyda Shakiba ◽  
Stacey M. Louie
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Water Treatment ◽  
Water Chemistry ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Hard Water ◽  
Aggregation State ◽  
Byproduct Formation ◽  
Partial Dissociation

Immobilization of titanium dioxide nanoparticles (TiO<sub>2</sub> NPs) facilitates their removal and reuse in water treatment applications. Composite materials of electrostatically-bound TiO<sub>2</sub> NPs and zeolite particles have been proposed, but limited mechanistic studies are available on their performance in complex media. This study delineates the relative importance of homo- and heteroaggregation, water chemistry, and surface fouling by natural organic matter (NOM) on the photocatalytic degradation of diethyltoluamide (DEET) by TiO<sub>2</sub>-zeolite composites. Zeolite adsorbs a portion of the DEET, rendering it unavailable for degradation; corrections for this adsorption depletion allowed appropriate comparison of the reactivity of the composites to the NPs alone. The TiO<sub>2</sub>-zeolite composites showed enhanced DEET degradation in moderately hard water (MHW) compared to deionized water (DIW), likely attributable to the influence of HCO<sub>3</sub><sup>−</sup>, whereas a net decline in reactivity was observed for the TiO<sub>2</sub> NPs alone upon homoaggregation in MHW. The composites also better maintained reactivity in the presence of NOM in MHW, as removal of Ca<sup>2+</sup> onto the zeolite mitigated fouling of the TiO<sub>2</sub> surface by NOM. However, NOM induced partial dissociation of the composites. DEET byproduct formation, identified by quadrupole–time of flight (QTOF) mass spectrometry, was generally unaffected by the zeolite, while NOM fouling favored de-ethylation over hydroxylation products. Overall, the most significant factor influencing TiO<sub>2</sub> reactivity toward DEET was NOM adsorption, followed by homoaggregation, electrolytes (here, MHW versus DIW), and heteroaggregation. These findings can inform a better understanding of NP reactivity in engineered water treatment applications.

Partial dissociation of water on a MgO(100) film

2003 ◽  
Vol 68 (11) ◽  
Author(s):  
Yinghui Yu ◽  
Qinlin Guo ◽  
Shuang Liu ◽  
Enge Wang ◽  
Preben J. Møller
Keyword(s):  
Partial Dissociation
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