ARTICLE | doi:10.20944/preprints202107.0284.v1
Subject: Chemistry, Analytical Chemistry Keywords: entropy; enthalpy; equilibrium; ergal; free energy; Gibbs energy; Haber process; Helmholtz energy; hydrogen dissociation; transition state; water dissociation; virial theorem
Online: 13 July 2021 (09:57:00 CEST)
Clausius’ virial theorem set a basis for relating kinetic energy in a body of independent material particles to its potential energy, pointing to their complementary role with respect to the second law of maximum entropy. In action mechanics, expressing the entropy of ideal gases as a capacity factor for sensible heat or enthalpy plus the configurational work to sustain the relative translational, rotational and vibrational action yields algorithms for estimating chemical reaction rates and positions of equilibrium. All properties of state including entropy, work potential as Helmholtz and Gibbs energies and activated transition state reaction rates can be estimated, using easily accessible molecular properties, such as atomic weights, bond lengths, moments of inertia and vibrational frequencies. Understanding how Clausius’ virial theorem balances the internal kinetic energy with field potential energy justifies partitioning between thermal and statistical properties of entropy, yielding a more complete view of the evolutionary nature of the second law of thermodynamics. The ease of performing these operations is illustrated by three important chemical gas phase reactions, the reversible dissociation of the hydrogen molecules, lysis of water to hydrogen and oxygen and the reversible formation of ammonia from nitrogen and hydrogen. Employing the ergal also introduced by Clausius to define the reversible internal work to overcome molecular interactions plus the configurational internal work of negative Gibbs energy as a function of volume or pressure may provide a practical guide for managing risk in industrial processes and climate change at the global scale.
ARTICLE | doi:10.20944/preprints202212.0096.v1
Subject: Chemistry, Electrochemistry Keywords: bipolar membrane; mathematical modelling; water dissociation; water-splitting kinetics
Online: 6 December 2022 (09:39:51 CET)
A model is proposed that describes the transfer of ions and the process of water dissociation in a system with a bipolar membrane and adjacent diffusion layers. The model considers the transfer of four types of ions: the cation and anion of salt and the products of water dissociation – hydrogen and hydroxyl ions. To describe the process of water dissociation, a model for accelerating the dissociation reaction with the participation of ionogenic groups of the membrane is adopted. The boundary value problem is solved numerically using COMSOL® Multiphysics 5.5 software. An analysis of the results of a numerical experiment shows that, at least in a symmetric electromembrane system, there is a kinetic limitation of the water dissociation process, apparently associated with the occurrence of water recombination reaction at the of the bipolar region. An interpretation of the entropy factor (β) is given as a characteristic length which shows the possibility of an ion that appeared as a result of the water dissociation reaction to be removed from the reaction zone without participating in recombination reactions.
ARTICLE | doi:10.20944/preprints202002.0393.v1
Subject: Physical Sciences, Other Keywords: assessment of gases; carbon dioxide dissociation; plasma generator; OES spectroscopy method
Online: 26 February 2020 (11:28:16 CET)
The paper focuses of the interaction between tungsten (W) wire and microwave field in carbon dioxide (CO2) atmosphere. Our experimental set-up uses a microwave plasma generator in order to generate the plasma from the metallic wires. The microwave plasma generator contain a cylindrical cavity - TM_011 propagation modes, commercial source (magnetron) having the 2.45 GHz frequency at 800 W microwave and power supply. In the focal point of the cylindrical cavity we have a high energy of the electromagnetic radiation. The metallic wires from this area will be vaporized and ionized having as effect CO2 dissociation. The electron temperature regarding metallic plasma produced was estimated using the ratio of atomic emission lines acquired by a high definition of the optical multichannel spectrometer. Determination of the CO2 dissociation quantity was estimated measuring of the carbon monoxide (CO) resulting of the CO2 dissociation process. We obtained a high electron temperature of the plasma and a strong dissociation of the CO2.
ARTICLE | doi:10.20944/preprints202005.0427.v2
Subject: Medicine & Pharmacology, Allergology Keywords: Isolation; Neural Crest-derived Stem Cells; Mechanical Dissociation; Regenerative Periodontology, Enzymatic Digestion
Online: 2 November 2020 (11:35:16 CET)
Periodontitis is microbial infection affecting periodontium, the tooth supporting structure and affects >743 million people worldwide. Neural crest-derived stem cells (NCSCs) hold the promise to regenerate the damaged periodontium. These cells have been identified within adult adipose tissue, periodontal ligament, and palatal tissue. Typical enzymatic isolation protocols are expensive, time consuming and often not clinically compliant. Enzyme-free, mechanical dissociation has been suggested as an alternative method of generating cell suspensions required for cell separation and subsequent expansion ex vivo. In our study, samples of rat skeletal muscle tissue were used to appraise the suitability of a novel mincing method of mechanical dissociation against enzymatic digestion with collagenase and dispase. Skeletal muscle is readily available and has been shown to contain NCSC populations. We used a Rigenera-Human Brain Wave® prototype mincer to produce a suspension of skeletal muscle-derived cells modeling NCSCs. We have compared the resulting cell cultures produced via mechanical dissociation and enzymatic dissociation, producing single cell suspensions suitable for Magnetic Cell Sorting (MACs) and Fluorescence-activated cell sorting (FACS). Despite the Countess Automated Cytometry data demonstrating that cell suspensions produced by mechanical dissociation (n=24) contain on average 26.8 times as many viable cells as enzymatic cell suspensions (n=18), enzymatic suspensions produced more successful cell cultures. Spheroids and subsequently adherent cells formed from 4 enzymatic cell suspensions (44.4%) vs. 1 mechanical cell suspension (8.3%). Enzymatic digestion protocols formed spheroids faster and more plentifully than mechanical cell suspensions. Adherent cells and spheroids isolated via both methods appear morphologically similarly to NCSCs from our previous studies.
REVIEW | doi:10.20944/preprints201906.0269.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: subjective paranormal experience, homeostasis, trauma, dissociation, depersonalisation, compartmentalisation, fantasy proneness, safety, control, survival
Online: 26 June 2019 (13:59:44 CEST)
Subjective paranormal experience (SPE) has been a notable part of the human historical narrative. Alleged miracles, telepathy, clairvoyance, precognition, witchcraft, spiritualism, monsters and ghosts have received a supernatural interpretation. The incidence and prevalence of reported SPE remains at high levels in all populations investigated to date. Previous research on SPE has focused on the cognitive and social factors that facilitate paranormal beliefs and experiences. I consider here developmental factors in the brain’s responses to trauma that appear to predispose certain individuals towards SPE. The theory draws upon the established mechanisms of dissociation and fantasy generation to describe and explain the origins of paranormal experience. The theory hypothesizes that childhood abuse and victimization trigger autonomic responses of dissociation, depersonalization and compartmentalization. Freezing and associated releases of fantasy serve as a survival strategy in the homeostatic regaining of safety and control. The predictions from the homeostasis theory are consistent with the findings of multiple studies and falsifying evidence has yet to be identified.
REVIEW | doi:10.20944/preprints202002.0458.v1
Subject: Life Sciences, Biophysics Keywords: LacI; Lac repressor; TetR; TAL-Effector; transcription activator-like effector; Cas9d; dissociation rate constant
Online: 29 February 2020 (09:13:12 CET)
The recent developments in the delivery and design of transcription factors put their therapeutic applications within reach, exemplified by cell replacement, cancer differentiation and T-cell based cancer therapies. The success of such applications depends on the efficacy and precision in the action of transcription factors. The biophysical and genetic characterization of the paradigmatic prokaryotic repressors, LacI and TetR and the designer transcription factors, TALE and CRISPR-Cas9 revealed common rules, which can help the optimization of activators and repressors. Further studies will be required to analyze the linkage between dissociation constants and enzymatic activity, the role of phase separation and squelching in activation and repression, and the long-range interaction of transcription factors with epigenetic regulators in the context of the chromosomes. Understanding these mechanisms will help to tailor systematically optimized designer transcription factors to the needs of specific applications.
ARTICLE | doi:10.20944/preprints201812.0082.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Brain injury, coma, consciousness, cognitive motor dissociation, disorders of consciousness, ethics, neurorehabilitation, traumatic brain injury
Online: 6 December 2018 (10:05:52 CET)
Background: The vegetative state (VS)/unresponsive wakefulness syndrome (UWS) denotes brain-injured, awake patients who are seemingly without awareness. Still, up to 15% of these patients show signs of covert consciousness when examined by functional magnetic resonance imaging (fMRI) or EEG, which is known as cognitive motor dissociation (CMD). Most experts prefer the term unresponsive wakefulness syndrome to avoid the negative connotations associated with vegetative state and to highlight the possibility for CMD. However, the perception of VS/UWS by the public has never been studied systematically. Methods: Using an online crowdsourcing platform, we recruited 1297 participants from 32 countries. We investigated if vegetative state and unresponsive wakefulness syndrome might have a different influence on attitudes towards VS/UWS and CMD. Results: Participants randomized to be inquired about the vegetative state believed that CMD was less common (mean estimated frequency in unresponsive patients 38.07% ± SD 25.15) than participants randomized to unresponsive wakefulness syndrome (42.29% ± SD 26.63; p=0.016). Attitudes towards treatment withdrawal were similar. Most participants preferred unresponsive wakefulness syndrome (60.05%), although a sizeable minority favored vegetative state (24.21%; difference 35.84%, 95% CI 29.36 to 41.87; p<0.0001). Searches on PubMed and Google Trends revealed that unresponsive wakefulness syndrome is increasingly used by academics but not lay people.Discussion: Simply replacing vegetative state with unresponsive wakefulness syndrome may not be fully appropriate given that 1 of 4 prefer the first term. We suggest that physicians take advantage of the controversy around the terminology to explain relatives the concept of CMD and its ethical implications.
ARTICLE | doi:10.20944/preprints202207.0110.v1
Subject: Mathematics & Computer Science, Applied Mathematics Keywords: associative learning; molecular circuits; synthetic biology; mathematical modeling; Hill equation; Pavlov’s dog; reinforcement; dissociation; non-dimensionalization
Online: 7 July 2022 (04:38:20 CEST)
The development of synthetic biology has enabled us to make massive progress on biotechnology and to approach research questions from a brand new perspective. In particular, the design and study of gene regulatory networks in vitro, in vivo and in silico, have played an increasingly indispensable role in understanding and controlling biological phenomena. Among them, it is of great interest to understand how associative learning is formed at the molecular circuit level. Noticeably, mathematical models have been increasingly used to predict the behaviors of molecular circuits. The Fernando’s model, which is thought to be one of the first works in this line of research using the Hill equation, attempted to design a synthetic circuit that mimics Hebbian learning in the neural network architecture. In this article, we carry out in-depth computational analysis of the model and demonstrate that the reinforcement effect can be achieved by choosing the proper parameter values. We also construct a novel circuit that can demonstrate forced dissociation, which was not observed in the Fernando’s model. Our work can be readily used as reference for synthetic biologists who consider implementing the circuits of this kind in biological systems.