Substantive nature of sleep in updating the temporal conditions necessary for inducing units of internal sensations

Unlike other organs that operate continuously, such as the heart and kidneys, many of the operations of the nervous system shut down during sleep. The evolutionarily conserved unconscious state of sleep that puts animals at risk from predators indicates that it is an indispensable integral part of systems operation. A reasonable expectation is that any hypothesis for the mechanism of the nervous system functions should be able to provide an explanation for sleep. In this regard, the semblance hypothesis is examined. Postsynaptic membranes are continuously being depolarized by the quantally released neurotransmitter molecules arriving from their presynaptic terminals. In this context, an incidental lateral activation of the postsynaptic membrane is expected to induce a semblance (cellular hallucination of arrival of activity from its presynaptic terminal, which forms a unit for internal sensation) of the arrival of activity from its presynaptic terminal as a systems property. This restricts induction of semblance to a context of a very high ratio of the duration of the default state of neurotransmitter-induced postsynaptic depolarization to the total duration of incidental lateral activations of the postsynaptic membrane. This requirement spans within a time-bin of a few sleep-wake cycles. Since the duration of quantal release remains maximized, the above requirement can be achieved only by ceiling the total duration of incidental lateral activations of the postsynaptic membrane, which necessitates a state of sleep

A pressure-reversible cellular mechanism of general anesthetics capable of altering a possible mechanism of consciousness

Different anesthetics are known to modulate different types of membrane-bound receptors. Their common mechanism of action is expected to alter the mechanism for consciousness. Consciousness is hypothesized as the integral of all the units of internal sensations induced by reactivation of inter-postsynaptic membrane functional LINKs during mechanisms that lead to oscillating potentials. The thermodynamics of the spontaneous lateral curvature of lipid membranes induced by lipophilic anesthetics can lead to the formation of non-specific inter-postsynaptic membrane functional LINKs by different mechanisms. These include direct membrane contact by excluding the inter-membrane hydrophilic region and readily reversible partial membrane hemifusion. The constant reorganization of the lipid membranes at the lateral edges of the postsynaptic terminals (dendritic spines) resulting from AMPA receptor-subunit vesicle exocytosis and endocytosis can favor the effect of anesthetic molecules on lipid membranes at this location. Induction of a large number of non-specific LINKs can alter the conformation of the integral of the units of internal sensations that maintain consciousness. Anesthetic requirement is reduced in the presence of dopamine that causes enlargement of dendritic spines. Externally applied pressure can transduce from the middle ear through the perilymph, cerebrospinal fluid, and the recently discovered glymphatic pathway to the extracellular matrix space, and finally to the paravenular space. The pressure gradient reduce solubility and displace anesthetic molecules from the membranes into the paravenular space, explaining the pressure reversal of anesthesia. Changes in membrane composition and the conversion of membrane hemifusion to fusion due to defects in the checkpoint mechanisms can lead to cytoplasmic content mixing between neurons and cause neurodegenerative changes. The common mechanism of anesthetics presented here can operate along with the known specific actions of different anesthetics

Framework of Consciousness from Semblance of Activity at Functionally LINKed Postsynaptic Membranes

Consciousness is seen as a difficult “binding” problem. Binding, a process where different sensations evoked by an item are associated in the nervous system, can be viewed as a process similar to associative learning. Several reports that consciousness is associated with some form of memory imply that different forms of memories have a common feature contributing to consciousness. Based on a proposed synaptic mechanism capable of explaining different forms of memory, we developed a framework for consciousness. It is based on the formation of semblance of sensory stimulus from (1) synaptic semblances when excitatory postsynaptic potentials arrive at functionally LINKed postsynaptic membranes, and (2) network semblances when these potentials summate to elicit action potential initiating activity in a network of neurons. It is then possible to derive a framework for consciousness as a multi-dimensional semblance. According to this framework, a continuum of semblances formed from background sensory stimuli and oscillating neuronal activities serve to maintain consciousness. Feasibility of this framework to explain various physiological and pathological states of consciousness, its subjective nature and qualia is examined

The nature of “internal sensations” of higher brain functions may be derived from the design rules for artificial machines that can produce them

Modeling various neuronal functions in search of emergent properties may achieve success when the gold standard of replicating the models in physical systems starts exhibiting some of these properties. Since very large number of functions can be modeled and need testing, we suggest an alternate method of examining higher brain functions: seeing them as internal sensations formed from their hypothetical basic units. Here, we explain the need to replicate the natural mechanism using electronic circuits, discuss some of the technical aspects and introduce some concepts for searching for properties of internal sensations evolving from them

Processing Semblances Induced through Inter-Postsynaptic Functional LINKs, Presumed Biological Parallels of K-Lines Proposed for Building Artificial Intelligence

The internal sensation of memory, which is available only to the owner of an individual nervous system, is difficult to analyze for its basic elements of operation. We hypothesize that associative learning induces the formation of functional LINK between the postsynapses. During memory retrieval, the activation of either postsynapse re-activates the functional LINK evoking a semblance of sensory activity arriving at its opposite postsynapse, nature of which defines the basic unit of internal sensation – namely, the semblion. In neuronal networks that undergo continuous oscillatory activity at certain levels of their organization re-activation of functional LINKs is expected to induce semblions, enabling the system to continuously learn, self-organize, and demonstrate instantiation, features that can be utilized for developing artificial intelligence (AI). This paper also explains suitability of the inter-postsynaptic functional LINKs to meet the expectations of Minsky’s K-lines, basic elements of a memory theory generated to develop AI and methods to replicate semblances outside the nervous system

Prevalence of type and etiology of lung cancer among the patients presented to a tertiary care hospital at central Kerala: a descriptive study

Background: Lung cancer remains the most common cause of premature mortality in men in developing countries. This study was aimed to evaluate the type and etiological factors of lung cancer in patients presented to a tertiary care hospital of central Kerala.Methods: A retrospective descriptive study was conducted in patients who were diagnosed as lung cancer. The medical records of such patients were reviewed. The data such as age, gender, etiological risk factors and type of lung cancer were collected. Patients with incomplete reports or repeated tests, or histopathological findings were negative for lung cancers were excluded from the study.Results: Total 228 patients were included in the study with age of 64.71± 9.75. The male (198) and female (30) ratio was 6.6:1, indicated the male dominance. Among the histological types, the squamous cell carcinoma was 29% (68/228) found as the most prevalent type which is followed by adenocarcinoma 26 % (61/228). The right side (132/228) lobe was the major segment than the left side (91/228). Similarly, incidence in the central region (128/228) was more than the peripheral region (69/228). Among the right side, the upper lobe was dominant when compared to the lower or middle lobe. The lower left lobe incidence was found in 47/228 cases. Among the total, 188 cases were tobacco smokers while the remaining were nonsmokers.Conclusions: Squamous cell carcinoma with right side upper lobe of lung was prevalent among the lung cancer cases. Tobacco smoking was found to be the major etiological factor

Transport in Flat Heat Pipes at High Heat Fluxes from Multiple Discrete Sources

A three-dimensional model has been developed to analyze the transient and steady-state performance of flat heat pipes subjected to heating with multiple discrete heat sources. Three-dimensional flow and energy equations are solved in the vapor and liquid regions, along with conduction in the wall. Saturated flow models are used for heat transfer and fluid flow through the wick. In the wick region, the analysis uses an equilibrium model for heat transfer and a Brinkman-Forchheimer extended Darcy model for fluid flow. Averaged properties weighted with the porosity are used for the wick analysis. The state equation is used in the vapor core to relate density change to the operating pressure. The density change due to pressurization of the vapor core is accounted for in the continuity equation. Vapor flow, temperature and hydrodynamic pressure fields are computed at each time step from coupled continuity/momentum and energy equations in the wick and vapor regions. The mass flow rate at the interface is obtained from the application of kinetic theory. Predictions are made for the magnitude of heat flux at which dryout would occur in a flat heat pipe. The input heat flux and the spacing between the discrete heat sources are studied as parameters. The location in the heat pipe at which dryout is initiated is found to be different from that of the maximum temperature. The location where the maximum capillary pressure head is realized also changes during the transient. Axial conduction through the wall and wick are seen to play a significant role in determining the axial temperature variation

Comparison of diagnostic yield and complications of bronchoscopy, closed pleural biopsy and medical thoracoscopic pleural biopsies in undiagnosed pleural effusions

Background: Undiagnosed exudative pleural effusion is a commonly encountered clinical scenario, which requires further evaluation. This study was aimed to analyze the diagnostic yield and complications of three procedures- Bronchoscopy, closed (Abram’s) pleural biopsy and medical thoracoscopy. Further, this study assessed whether combining closed pleural biopsy with bronchoscopy can be a substitute for medical thoracoscopy.Methods: An observational study was conducted among people with undiagnosed exudative pleural effusion. Initially, closed pleural biopsies were performed with Abrams needle and multiple tissue fragments were taken through the incision and the samples were sent in formalin to the laboratory for histopathology examination. For thoracoscopy, a cannula of 10 mm diameter with blunt trocar was inserted into the pleural cavity and semi rigid thoracoscope was introduced through the trocar. Bronchoscopy was performed 48 hours after thoracoscopy. Sensitivity, specificity and positive and negative predictive values were calculated and compared.Results: Out of 25 people, 14 were diagnosed to have malignancy and 7 were diagnosed tuberculosis. The overall sensitivity of the three procedures were 28.5% for closed pleural biopsy, 14.2% for bronchoscopy, 95.2% for medical thoracoscopy, 42.8% for the combined pleural biopsy and bronchoscopy. The complication rate was lowest for bronchoscopy (4%), followed by medical thoracoscopy (8%) and closed pleural biopsy (16%).Conclusions: Medical thoracoscopy is a comparatively safe procedure which has got the highest sensitivity for the diagnosis of undiagnosed exudative pleural effusions. Bronchoscopy combined with closed pleural biopsy, the diagnostic yield was increased (than that of individual yield), but cannot be a substitute for medical thoracoscopy