In the cytoplasm of practically all living cells, potassium is the major cation while sodium dominates in the media (seawater, extracellular fluids). Both prokaryotes and eukaryotes have elaborate mechanisms and spend significant energy to maintain this asymmetric K+/Na+ distribution. This essay proposes an original line of evidence to explain how bacteria selected potassium at the very beginning of the evolutionary process and why it remains essential for eukaryotes.

Although Boyle has been regarded as a champion of the seventeenth century Cartesian mechanical philosophy, I defend the position that Boyle’s views conciliate between a strictly mechanistic conception of fundamental matter and a non-reductionist conception of chemical qualities. In particular, I argue that this conciliation is evident in Boyle’s ontological distinction between fundamental corpuscles endowed with mechanistic properties and higher-level corpuscular concretions endowed with chemical properties. Some of these points have already been acknowledged by contemporary scholars, and I actively engage (...) with their ideas in this paper. However I attempt to contribute to the debate over Boyle’s mechanical philosophy by arguing that Boyle’s writings suggest an emergentist, albeit still mechanistic, notion of chemical properties. I contrast Boyle’s views against those of strict reductionist mechanical philosophers, focusing on the famous debate with Spinoza over the redintegration of niter, and argue that Boyle’s complex chemical ontology provides a more satisfactory understanding of chemical phenomena than is provided by a strictly reductionist and Cartesian mechanical philosophy. (shrink)

The importance of electrical signalling in bacteria is an emerging paradigm. Bacillus subtilis biofilms exhibit electrical communication that regulates metabolic activity and biofilm growth. Starving cells initiate oscillatory extracellular potassium signals that help even the distribution of nutrients within the biofilm and thus help regulate biofilm development. Quorum sensing also regulates biofilm growth and crucially there is convergence between electrical and quorum sensing signalling axes. This makes B. subtilis an interesting model for cell signalling research. SpoOF is predicted to (...) act as a logic gate for signalling pathway convergence, raising interesting questions about the functional nature of this gate and the relative importance of these disparate signals on biofilm behaviour. How is an oscillating signal integrated with a quorum signal? The model presented offers rich opportunities for future experimental and theoretical modelling research. The importance of direct cell‐to‐cell electrical signalling in prokaryotes, so characteristic of multicellular eukaryotes, is also discussed. (shrink)

N‐type inactivation of potassium channels is controlled by cytosolic loops that are intrinsically disordered. Recent experiments have shown that the mechanism of N‐type inactivation through disordered regions can be stereospecific and vary depending on the channel type. Variations in mechanism occur despite shared coarse grain features such as the length and amino acid compositions of the cytosolic disordered regions. We have adapted a phenomenological model designed to explain how specificity in molecular recognition is achieved through disordered regions. We propose (...) that the channel‐specific observations for N‐type inactivation represent distinct mechanistic choices for achieving function through conformational selection versus induced fit. It follows that the dominant mechanism for binding and specificity can be modulated through subtle changes in the amino acid sequences of disordered regions, which is interesting given that specificity in function is realized in the absence of autonomous folding. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Philosophy, Psychiatry, & Psychology 9.3 (2002) 219-227 [Access article in PDF] The Practical Kinds Model as a Pragmatist Theory of Classification Peter Zachar Pragmatist theories of scientific classification are intended to be pluralistic models that recognize different ways of cutting up the world as valuable, but do not require us to adopt whatever-goes relativism or metaphysical antirealism. How ironic that my application of pragmatism to psychopathology has been charged (...) with not being sufficiently pluralistic because it tries to fit all psychiatric disorders into the Procrustean bed of practical kinds. The Practical Kinds Model in General As a point of clarification, the practical kinds model is not a description of a type of category combined with an argument that all psychiatric disorders should be seen as belonging to that type. If it were that kind of model, I would fully agree with Haslam that practical kinds, fuzzy kinds, and discrete kinds are all potential types of psychiatric disorders. Like Nick Haslam, I believe that there are many different things in the DSM-IV and the ICD-10, and they cannot neatly be classified as the same type of thing.Rather than identifying a type of category, the practical kinds model is a general theory of scientific classification. It is a nonessentialistic theory. Essentialism is the view that things have real essences. In the Aristotelian version of essentialism, an essence is an internal structure, and it is the internal structure that makes anything be the kind of thing it really is. In this classical category model, category members either have the essence or they do not, and everything that has the appropriate essence is a member of that category. The world is supposed to therefore have a well-defined structure, and the job of the scientist is to discover that structure. Ian Hacking (1999) has termed this view of categorization inherent structurism.The practical kinds model does not deny that things have internal structures; it only denies that internal structure by itself determines category membership. Internal structure is an important consideration in identifying categories, but external criteria can always play a role. External or relational criteria play more important roles in some cases than they do in others, but they cannot be eliminated once and for all. Essentialistic theories, which favor an almost exclusive focus on inherent structures, have the advantage of being more parsimonious, but they do so by ignoring real complexity.The best way to illustrate this point is to examine a category whose identification is heavily weighted in terms of internal criteria, or an inherent structure, such as a chemical element. [End Page 219] For example, hydrogen is defined as the element that has an atomic number of 1. This means that it has one proton in its nucleus and normally one electron orbiting its nucleus. The atomic number reflects an internal property, and anything that has an atomic number of 1 is hydrogen. The same is true for the other elements. Anything that has an atomic number of 79 is gold; anything that has an atomic number of 19 is potassium, and so on. Also part of the essentialistic view is the notion that all the important properties of an element are systematically (or lawfully) related to its internal structure.It would be foolish to deny the practical utility of the atomic theory of chemistry. But even in this strongest of cases, external criteria can potentially play a role in how we decide to carve up the world and what we identify as the relevant categories. The point can be clearly illustrated with a Gedanken experiment based on the ideas of Donnellan (1983). Assume that we were to make contact with extraterrestrial life, and the result of that contact was our initiation into a larger galactic community like those portrayed on Star Trek or Babylon 5. Fortunately for us, it turns out that all planets in the community use a gold-based currency, just like we do on Earth. What we call gold, however, is too common to be the galactic basis of a currency, but a particular isotope... (shrink)

In the year 2060, sophisticated investigative tools can help catch a killer. But there are some questions even the most advanced technologies cannot answer... Harlan Coben says, “J.D. Robb’s In Death novels are can’t-miss pleasures.” Her latest is no exception, as the priest at a Catholic funeral mass brings the chalice to his lips—and falls over dead... When Detective Lieutenant Eve Dallas confirms that the consecrated wine contained potassium cyanide, she’s determined to solve the murder of Father Miguel Flores, (...) despite her discomfort with her surroundings. It’s not the bodegas and pawn shops of East Harlem that bother her, though the neighborhood is a long way from the stone mansion she shares with her billionaire husband Roarke. It’s all that holiness flying around at St. Christobal’s that makes her uneasy. A search of the victim’s sparsely furnished room reveals little—except for a carefully hidden religious medal with a mysterious inscription, and a couple of underlined Bible passages. The autopsy reveals more: faint scars of knife wounds, a removed tattoo—and evidence of plastic surgery suggesting “Father Flores” may not be the man his parishioners thought. Now, as Eve pieces together clues that suggest identity theft, gang connections, and a deeply personal act of revenge, she hopes to track down whoever committed this unholy act. Until a second murder—in front of an even larger crowd of worshippers—knocks the whole investigation sideways. Raves for the In Death novels: “A taut, nerve-jangling, thriller.”—Ridley Pearson “A thrills-to-chills ratio that will raise the neck hairs of even the most jaded reader.”—Dennis Lehane “An authentic page-turner.”—Stephen King. (shrink)

This chapter examines the work in chemistry that led to the discovery of boron and explores the implications of this episode for the scientific realism debate. This episode begins with Lavoisier’s oxygen theory of acidity and his prediction that boracic acid contains oxygen and a hypothetical, combustible substance that he called the boracic radical. And it culminates in the work of Davy, Gay-Lussac, and Thénard, who used potassium to extract oxygen from boracic acid and thereby discovered boron. This episode (...) constitutes a novel predictive success of Lavoisier’s theory of acidity, which was not even approximately true. Selective realists attempt to accommodate such false-but-successful theories by showing that their success is due to the fact that they have approximately true parts. This episode poses a strong challenge to selective realism because the parts of Lavoisier’s theory that are responsible for its success are not even approximately true. (shrink)

SUR2, similar to SUR1, is a regulatory subunit of the ATP‐sensitive potassium channel (KATP), which plays a key role in numerous important physiological processes and is implicated in various diseases. Recent structural studies have revealed that, like SUR1, SUR2 can undergo ligand‐dependent dynamic conformational changes, transitioning between an inhibitory inward‐facing conformation and an activating occluded conformation. In addition, SUR2 possesses a unique inhibitory Regulatory helix (R helix) that is absent in SUR1. The binding of the activating Mg‐ADP to NBD2 (...) of SUR2 competes with the inhibitory Mg‐ATP, thereby promoting the release of the R helix and initiating the activation process. Moreover, the signal generated by Mg‐ADP binding to NBD2 might be directly transmitted to the TMD of SUR2, prior to NBD dimerization. Furthermore, the C‐terminal 42 residues (C42) of SUR2 might allosterically regulate the kinetics of Mg‐nucleotide binding on NBD2. These distinctive properties render SUR2 intricate sensors for intracellular Mg‐nucleotides. (shrink)

Mr. Paul Mills suffered from cancer of the esophagus. Three major surgeries were unsuccessful in correcting the problem, and other treatment methods likewise failed. His condition deteriorated to the point where there was no longer any hope of recovery. Dr. Morrison, who was Mr. Mills's intensive care physician at the Queen Elizabeth II Health Sciences Centre in Halifax, and Mr. Mills's family agreed that active life support should be discontinued. Dr. Morrison then removed Mr. Mills's ventilator. To everyone's surprise, and (...) dismay, Mr. Mills did not die. He continued to breathe spontaneously and started to show signs of distress. Dr. Morrison increased the dosage of morphine, to no effect. She increased it again to the point where death could reasonably be expected to occur; signs of distress continued. Dr. Morrison at this point administered a dose of potassium chloride and Mr. Mills died. (shrink)

The Classical Theory of function in the nervous system postulates that the nerve impulse is the result of a sequential reversal of the membrane potential due to an increased permeability of the membrane, first to sodium ions, then to potassium ions. The new theory presents a bio-physical model which depicts the nerve impulse as an event involving the motions of electrons and waves, and their interactions with sodium and potassium atoms and ions. The velocity of the nerve impulse (...) (the most important parameter of nerve function) is determined by the product of two constants: c = the speed of light, which is a constant for all nerves; k =a constant for each nerve and is believed to be a specific property of nerve matter related in some way to the atomic process. The theory proposes that the nerve impulse in the axon is dualistic in nature (particles and waves play equally significant roles). The dualistic nature accounts for the three most fundamental characteristics of conduction of the nerve impulse: periodicity (conduction of a nerve impulse over long distances with constant velocity and form); non-summing (two nerve impulses cannot be in the same place at the same time); quantum nature of each nerve impulse — i.e., the unit message of the nerve impulse is an indivisible unit. (shrink)

Photo by Hannah Busing on Unsplash INTRODUCTION Religion has long provided guidance that has led to standards reflected in some aspects of medical practices and traditions. The recent bioethical literature addresses numerous new problems posed by advancing medical technology and demonstrates an erosion of standards rooted in religion and long widely accepted as almost axiomatic. In the deep soul-searching that pervades the publications on bioethics, several disturbing and dangerous trends neglect some basic lessons of philosophy, logic, and history. The bioethics (...) discourse on medical aid in dying emphasizes similarity over previously recognized important distinguishing features. For example, it overplays a likeness between assistance in dying and the withdrawal of life-saving technology. In many bioethics’ topics, arguments based on a logical continuum are used to question the lines demarcating important moral differences. l. The Line Between Ethical and Not: Logic Based on Continuum Careful case selection, often either end of a continuum, allows the tearing down or ridiculing of many rules and codes across most professions and fields of interest. This situation holds true for traffic laws as well as medical ethics guidelines. It is relatively simple for those who desire to attack a particular viewpoint by selecting a case that makes that position seem untenable. In the ethics realm, good and bad medicine exist at opposite ends of an ethical continuum, with many practices lying in between. For example, much of medical ethics exists between the Nazi criminal physicians and the most sainted nurse or physician. A gradual progression occurred over less than two decades from a utilitarian position that supported limited euthanasia for those with certain mental illnesses to genocide. German society embraced a utilitarian ethic in which the value of human life no longer was intrinsic but instrumental.[1] Many morally significant points on a continuum were then ignored as the misguided utilitarian policy rampantly continued. A point in the continuum to distinguish between ethically justifiable and that which is not can be difficult to identify compared to the two extremes. This continuum is not unique to ethics but can be applied to almost any other aspect of human life and endeavor. Between a severely ill schizophrenic person and a superbly well-adjusted individual, there is a continuum of mental and psychological function. The existence of a continuum should not paralyze thinking and prevent us from drawing lines and identifying moral differences based on objective criteria as well as moral philosophy. Yet, by focusing on a continuum, many bioethicists use logic to disregard dividing lines between an "ethical" and an "unethical" act. Unfortunately, sometimes bioethicists draw revolutionary conclusions that would change the scope of medical practices which is accepted as ethical. There are many examples of similar shifts on the continuum. Many authors argue for the ethical permissibility of abortion by pointing out that the human fetus is no different in various characteristics, one arguing it is as like an ape or chick as it is like a person,[2] and does not achieve unique human and individual characteristics until well into the first year of life.[3] While human fetuses arguably do not have certain distinctive qualities of personhood, most people shy away from the logical next conclusion: permitting infanticide. For example, Joshua Lederberg condemns infanticide, in the face of biological illogic, because of our emotional commitment to infants, to me, a relatively weak explanation. Sir Francis Crick suggests we might consider birth at two days of life in order to decide whether an infant is a "suitable" member of society.[4] Giublini and Minerva suggest that infanticide should be permissible since late pregnancy abortions are permissible, arguing there is no significant difference between a fetus just before birth and an infant just after birth.[5] Clearly the continuum approach would allow for subjective arguments in favor of later infanticide at other points many days post-birth. Years ago, with a cynical tone, I mentioned infanticide as a further step on the continuum beyond abortion, and I was rightly shouted down as being deliberately provocative to assert the logic would ever stretch so far. While it is not an accepted mainstream position, the movement in academic settings from widespread condemnation to limited possible acceptance of infanticide has taken place in an incredibly short time. Public opinion and medical opinion in these areas have shifted dramatically in a short time. In another area, from a biological and chemical point of view, there is a continuum from man down to a single carbon atom. Yet, it would not seem logical to ignore the emotional differences, the meaning of personhood, or the moral distinction between killing an insect and killing a person. ll. A False Continuum: Medical Aid in Dying I assert that there has been an erosion of ethical guidelines in recent years attributable to using continuums to camouflage important distinctions. James Rachels’ work on active and passive euthanasia, which contends that the two are ethically identical, exemplifies that logic.[6] He illustrates this thesis, using a continuum to compare different scenarios with like consequences as morally equivalent, by comparing the deliberate drowning of a child with a deliberate failure to rescue a drowning child when easily able to do so. The author's comparison proposes that since much of the medical profession has already made peace with withholding treatment in order to hasten death, consistency inexorably demands that we permit active euthanasia as well.[7] When permission for active euthanasia was first introduced, it was limited exclusively to patients suffering severely from an intractable, incurable, and irreversible disease. These guidelines have been continuously eroded. There is now a substantial serious consideration for permitting active euthanasia of healthy elderly individuals who feel that they have completed their lives and are "tired of living."[8] There are many moral and factual differences along the ethical continuum. In human life, there is a difference between a live baby and a fetus, between a viable fetus and one that is not, between a fetus and a zygote, and between a zygote and a sperm cell. Similarly, there is a difference between pulling a trigger to kill someone and not interfering in preventing his death, which is reprehensible though both may be. There is a difference between not resuscitating an 80-year-old man with cancer when his heart stops and injecting him with a fatal dose of potassium chloride. I argue that an overt act of taking life repels civilized human beings is to be commended and encouraged as the reverence for human life or even for just a moment of human life is one of the great contributions of our civilization. CONCLUSION As an orthodox Jew, I feel that divinely inspired guidelines that have stood the test of centuries shape my beliefs, and such guidelines contradict medical aid in dying. I cannot speak to the viewpoint of those who do not access religion in defining their moral stance, nor do I implicate them in the current bioethics' trends, as I am not aware of the personal role of religion in the lives of most such authors. While many nonreligious people have a firm philosophical grounding and oppose medical aid in dying, I suggest that in the absence of any religious or other absolute standards, developing logically defensible ethical guidelines may be challenging. At the least, religion may play a role in defining the points on the continuums that are ethically meaningful and refuting the trending beliefs that if the endpoint is the same, allowing different methods of arriving at that end are somehow ethically equal. The continuum of ways death may result does not negate analysis of whether death is brought about in ways that recognize the importance of life. The German philosopher Hans Jonas said, "It is a question whether without restoring the category of the sacred, the category most thoroughly destroyed by the scientific enlightenment, we can have an ethics able to cope with the extreme powers that we possess today and constantly increase and are compelled to use."[9] While countries vary on the role of religion in policy, with many emphasizing freedoms of religion, a recent position paper released by a group of Jewish, Christian, and Moslem leaders suggested the need for agreement on the unique sanctity of human life.[10] I would recommend that such a document serve as an example of consensus on critical foundational bioethical guidelines for democratic secular societies. - [1] Alexander L Medical science under dictatorship. New England Journal of Medicine, 241, p39-47 DOI10.1056/NEJM194907142410201 [2] Lederberg J. A geneticist looks at contraception and abortion, Annals of Internal Medicine 67, sup 2, 25-27. https:/doi.org/10.7326/0003-4819-67-3-25 [3] Ibid. [4] Editorial, Sociology: Logic of biology. Nature 220, 429 https://www.nature.com/articles/220429b0 [5] Giublini A Minerva F After-birth abortion: why should the baby live. J Med Ethics 39, 261- [6] Rachels J Active and passive euthanasia. New England Journal of Medicine 292, 78-80 [7] Ibid. [8] Cohen-Almagor R Euthanizing people who are "tired of life". in Euthanasia and Assisted Suicide-Lessons from Belgium. Ch 11 of Euthanasia and Assisted Suicide, Cambridge University Press pp173-187. 2017 and DOI; https://doi.org/10.1017/9781108182799.012 [9] Hans Jonas, Technology and Responsibility: Reflections on the New Tasks of Ethics, 1972, found as Chapter IX, Philosophical Essays, 1980. https://inters.org/jonas-technology-responsability [10] A position paper of the Abrahamic Monotheistic religions on matters concerning the end-of-life. Vatican Press 28 October 2019 https://press.vatican.va/content/salastampa/en/bollettino/pubblico/2019/10/28/191028f.html. (shrink)

Classic voltaic batteries of the silver/zinc and copper/zinc types are the ancestors of today's primary cells, and facilitated the development of many aspects of electrical technology. Nevertheless, they appear never to have been studied and evaluated in a quantitative manner, with results recorded in terms of volts, amps, ohms, and watts. Research of this nature is reported here, and has been conducted for the most part with copper/zinc cells. Log–log graphs of voltage versus load and current, and power versus load, (...) are presented for many electrolyte systems. It has been shown that, although the textbook electrolyte of dilute sulphuric acid does work, it is an order of magnitude inferior to a solution containing some additional nitric acid. The latter diminishes the current‐limiting phenomenon of polarization, and was in fact used by Davy, Faraday, and other early investigators. A quantitative consideration of Nicholson and Carlisle's discovery of the electrolysis of water with a silver/zinc voltaic pile is followed by examination of the electrolysis of pure water, trough batteries, and Davy's isolation of potassium and sodium. Every battery gives maximum power when its resistance is adjusted to match the resistance of the load: the maximum output of the ‘Great Battery’ of the Royal Institution is assessed at no more than 3 kW. The paper concludes with a note on the recognized hazard of long‐term exposure to mercury vapour and its possible relevance to the health of Michael Faraday. (shrink)

In photoreceptors of a dark adapted eye, the inward flux of sodium and calcium ions in the outer segment is balanced by the outward flux of potassium ions. But in the presence of light the creation of cyclic guanosine monophosphate in the outer segment decreases. Due to low concentration of cG the channels in the outer segment open relatively less and thus the influx of calcium ion decreases, leading finally to hyperpolarization of the photoreceptors. We have analyzed theoretically the (...) effect of oxidizing iron ions on the photoreceptors. In order to explain the effects of iron-induced oxidative stress, the different molecules and ions involved in phototransduction are quantified leading to a differential equation for calculating the electroretinogram a-wave voltage. The theoretical results are compared with published experimental data. In the presence of light, the iron ions could push outward the similarly charged calcium ions resulting in a small increase in the amount of inward calcium flux. Again, the presence of iron ions generates Reactive Oxygen Species, and ROS could attract the calcium ions which also increases the calcium flux. This will result in a reduction in the amplitude and slope of the a-wave voltage in the electroretinogram. These results are parametrized in terms of calcium ion concentrations. As the amplitude of the a-wave shows how much electrical signal is produced, its reduction indicates reduction in the visual signal. Thus, the increase in iron ions could explain the reduction in the electrical signal due to iron-induced oxidative stress. (shrink)

A questionnaire survey was conducted at the annual meeting of the Japanese Society for Hospice and Home Care to study attitudes toward euthanasia. Respondents were asked how they agreed with the doctor's decision regarding several forms of euthanasia in hypothetical clinical situations dealing with terminal and non-terminal patients. Their acceptance of euthanasia was correlated with respect to patient's autonomy. Results showed 54% and 62% of respondents agreed with voluntary and non-voluntary passive euthanasia at the terminal stage, respectively. Indirect euthanasia was (...) accepted by 71%. In voluntary active euthanasia, 21% agreed with the doctor's act. In non-voluntary active euthanasia, 13% and 37% agreed with the use of potassium chloride and sedative, respectively. In dealing with a quadriplegic patient, 18% and 37% agreed with voluntary active euthanasia with a sedative and voluntary passive euthanasia. Voluntary passive euthanasia in the terminal stage and voluntary active and passive euthanasia and mercy killing were more likely to be favoured by the respondents who respected patient's autonomy than those who did not. (shrink)