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At least 235 records · Page 13Linked to original sources
arXiv2013

Correlation of multiple sclerosis incidence in the UK 1990-2010 with geomagnetic disturbances

Recently, Mackenzie et al. reported incidence and prevalence of multiple sclerosis (MS) in the UK from 1990-2010. Authors of this report indicated that they could not explain the cause of decreasing MS incidence trend in the UK during this time period. Such inability mainly resulted from the fact that often-cited hypotheses of MS, such as vitamin D deficiency hypothesis, cannot provide any answer for MS incidence trends. However, the newly proposed hypothesis of MS that is based on the biological effects of geomagnetic disturbances (GMD) has the ability to provide explanations for this observed trend. In this commentary, we showed that there is a significant correlation among alterations in GMD with changes in MS incidence and explained how researchers can use GMD hypothesis to evaluate such relations. Moreover, we clarified why we need a revision in the method of reporting MS incidence data to find actual environmental factor of MS.

q-bio.OT↗
arXiv2013

Genetic proof of chromatin diminution under mitotic agamospermy

The previously published data are examined on the base of the hypothesis about existence of differential polyteny of chromosomes and excess chromatin diminution during the first stages of embryogenesis. It has been concluded that available data provide the genetic proof that chromatin diminution is one of the mechanisms underlying the origin of polymorphism in sugar beet agamospermous progenies.

q-bio.OT↗
arXiv2013

Time series analysis of Parkinson's disease, Huntington's disease and Amyotrophic Lateral Sclerosis

The aim of this paper is to study the (clinical) time-series data of three diseases with complex dynamics: Parkinson's disease, Huntington's disease and Amyotrophic Lateral Sclerosis. For this purpose, first all of the time series data are embedded in a vector space of suitable dimension and then the correlation dimension of the above mentioned diseases is estimated. The results are also compared with healthy control subjects. At the next step, existence of chaos in these diseases is investigated by means of the so-called 0-1 test. The simulations show that none of the above mentioned diseases are chaotic.

q-bio.OT↗
arXiv2014

Possibilities of life around Alpha Centauri B

We make a preliminary assessment on the habitability of potential rocky exoplanets around Alpha Centauri B. We use several indexes: the Earth Similarity Index, a mathematical model for photosynthesis, and a biological productivity model. Considering the atmospheres of the exoplanets similar to current Earth's atmosphere, we find consistent predictions of both the Earth Similarity Index and the biological productivity model. The mathematical model for photosynthesis clearly failed because does not consider the temperature explicitly. For the case of Alpha Centauri B, several simulation runs give 11 planets in the habitable zone. Applying to them above mentioned indexes, we select the five exoplanets more prone for photosynthetic life; showing that two of them in principle have better conditions than Earth for this kind of life.

astro-ph.EP↗
arXiv2014

Foundations of biology

It is often stated that there are no laws in biology, where everything is contingent and could have been otherwise, being solely the result of historical accidents. Furthermore, the customary introduction of fundamental biological entities such as individual organisms, cells, genes, catalysts and motors remains largely descriptive; constructive approaches involving deductive reasoning appear, in comparison, almost absent. As a consequence, both the logical content and principles of biology need to be reconsidered. The present article describes an inquiry into the foundations of biology. The foundations of biology are built in terms of elements, logic and principles, using both the language and the general methods employed in other disciplines. This approach assumes the existence of a certain unity of human knowledge that transcends discipline boundaries. Leibniz's principle of sufficient reason is revised through the introduction of the complementary concepts of symmetry and asymmetry and of necessity and contingency. This is used to explain how these four concepts are involved in the elaboration of theories or laws of nature. Four fundamental theories of biology are then identified: cell theory, Darwin's theory of natural selection, an informational theory of life (which includes Mendel's theory of inheritance) and a physico-chemical theory of life. Atomism and deductive reasoning are shown to enter into the elaboration of the concepts of natural selection, individual living organisms, cells and their reproduction, genes as well as catalysts and motors. This work contributes to clarify the philosophical and logical structure of biology and its major theories. This should ultimately lead to a better understanding of the origin of life, of system and synthetic biology, and of artificial life.

q-bio.OT↗
arXiv2014

On the habitability of exoplanets orbiting Proxima Centauri

We apply a mathematical model for photosynthesis to quantitatively assess the habitability of a hypothetical planet orbiting Proxima Centauri, inside the so called habitability zone. Results suggest significant viability for primary biological productivity, provided living organisms have evolved to reach the ability of using infrared light for photosynthesis.

astro-ph.EP↗
arXiv2015

Entropy, biological evolution and the psychological arrow of time

We argue that in Universes where future and past differ only by the entropy content a psychological arrow of time pointing in the direction of entropy increase can arise from natural selection in biological evolution. We show that this effect can be demonstrated in very simple toy computer simulations of evolution in an entropy increasing or decreasing environment.

physics.gen-ph↗
arXiv2014

Responding to the AIDS epidemic in Angola

The epidemic of HIV in Angola started later and stabilized at lower levels than elsewhere in southern Africa. With a relatively small population and a high GDP, Angola is in a good position to intervene decisively to control HIV. The effectiveness, availability and affordability of anti-retroviral therapy (ART) make it possible to contemplate ending the epidemic of HIV/AIDS in Angola. We consider what would have happened without ART, the No ART counterfactual, the impact on the epidemic if the current roll-out of ART is maintained, the Current Programme, the impact if coverage is rapidly increased to reach 90% of people with CD4+ cell counts below 350/micro-litre by 2015 and HIV-positive pregnant women are all offered ART for life (Option B+), the Accelerated Programme, and what might be possible under the 2013 guidelines from the World Health Organization, starting in 2015 and reaching full coverage of ART by 2018, the Expanded Programme.If Angola is to reach the 2015 targets in the Presidents Acceleration Plan testing services will need to be expanded. A regular, uninterrupted supply of drugs will have to be assured. Existing health staff will need to be strengthened. Community health workers will need to be mobilized and trained to encourage people to be tested and accept treatment, to monitor progress and to support people on treatment; this in turn will help to reduce stigma and discrimination, loss to follow up of people diagnosed with HIV, and improve adherence for those on treatment. Effective monitoring and evaluation systems will have to be in place and data collection will have to be extended and improved to support the development of reliable estimates of the current and future state of the epidemic, the success of the programme, levels of viral load suppression for those on ART and the incidence of infection.

q-bio.OT↗
arXiv2014

Technological integration and hyper-connectivity: Tools for promoting extreme human lifespans

Artificial, neurobiological, and social networks are three distinct complex adaptive systems (CAS), each containing discrete processing units (nodes, neurons, and humans respectively). Despite the apparent differences, these three networks are bound by common underlying principles which describe the behaviour of the system in terms of the connections of its components, and its emergent properties. The longevity (long-term retention and functionality) of the components of each of these systems is also defined by common principles. Here, I will examine some properties of the longevity and function of the components of artificial and neurobiological systems, and generalise these to the longevity and function of the components of social CAS. In other words, I will show that principles governing the long-term functionality of computer nodes and of neurons, may be extrapolated to the study of the long-term functionality of humans (or more precisely, of the noemes, an abstract combination of existence and digital fame). The study of these phenomena can provide useful insights regarding practical ways that can be used in order to maximize human longevity. The basic law governing these behaviours is the Law of Requisite Usefulness, which states that the length of retention of an agent within a CAS is proportional to the contribution of the agent to the overall adaptability of the system. Key Words: Complex Adaptive Systems, Hyper-connectivity, Human Longevity, Adaptability and Evolution, Noeme

q-bio.OT↗
arXiv2013

Parkinson disease is a TH17 dominant autoimmune disorder against accumulated alpha-synuclein

Parkinson disease is a very common neurodegenerative disorder. Patients usually undergo destruction of substantia nigra to develop typical symptoms such as resting tremor, hypokinesia, and rigidity. However, the exact mechanism of Parkinson disease is still unknown, so it is called idiopathic Parkinsonism. According to my microarray analysis of peripheral blood leukocytes and substantia nigra brain tissue, I propose that Parkinson disease is actually a TH17 dominant autoimmune disease. Based on the microarray data in substantia nigra, HSP40, HSP70, HSP90, HSP27, HSP105, TLR5, TLR7, CEBPB, CEBPG, FOS, and caspase1 are significantly up-regulated. In peripheral leukocytes, NFKB1A, CEBPD, FOS, retinoic receptor alpha, suppressor of IKK epsilon, S100A11, G-CSF, MMP9, IL-1 receptor, IL-8 receptor, TNF receptor, caspase8, c1q receptor, cathepsin Z, HLA-G, complement receptor1, and complement 5a receptor. General immune related genes are also up-regulated including ILF2, CD22, CD3E, BLNK, ILF3, TCR alpha, TCR zeta, TCR delta, LAT, ITK, Ly9, and BANK1. The autoantigen is mainly alpha-synuclein. After knowing the exact disease pathophysiology, we can develop better drugs to prevent or control the detrimental disorder.

q-bio.OT↗
arXiv2014

Construction d'une plate-forme intégrée pour la cartographie de l'exposition des populations aux substances chimiques de l'environnement

L'analyse du lien entre l'environnement et la santé est devenue une préoccupation majeure de santé publique comme en témoigne l'émergence des deux Plans nationaux santé environnement. Pour ce faire, les décideurs sont confrontés au besoin de développement d'outils nécessaires à l'identification des zones géographiques dans lesquelles une surexposition potentielle à des substances toxiques est observée. L'objectif du projet Système d'information géographique (SIG), facteurs de risques environnementaux et décès par cancer (SIGFRIED 1) est de construire une plate-forme de modélisation permettant d'évaluer, par une approche spatiale, l'exposition de la population française aux substances chimiques et d'en identifier ses déterminants. L'évaluation des expositions est réalisée par le biais d'une modélisation multimédia probabiliste. Les problèmes épistémologiques liés à l'absence de données sont palliés par la mise en œuvre d'outils utilisant les techniques d'analyse spatiale. Un exemple est fourni sur la région Nord-Pas-de-Calais et Picardie, pour le cadmium, le nickel et le plomb. Le calcul de l'exposition est réalisé sur une durée de 70 ans sur la base des données disponibles autour de l'année 2004 sur une maille de 1 km de côté. Par exemple pour le Nord-Pas-de-Calais, les indicateurs permettent de définir deux zones pour le cadmium et trois zones pour le plomb. Celles-ci sont liées à l'historique industriel de la région : le bassin minier, les activités métallurgiques et l'agglomération lilloise. La contribution des différentes voies d'exposition varie sensiblement d'un polluant à l'autre. Les cartes d'exposition ainsi obtenues permettent d'identifier les zones géographiques dans lesquelles conduire en priorité des études environnementales de terrains. Le SIG construit constitue la base d'une plate-forme où les données d'émission à la source, de mesures environnementales, d'exposition, puis sanitaires et socio-économiques pourront être associées. -- Analysis of the association between the environment and health has become a major public health concern, as shown by the development of two national environmental health plans. For such an analysis, policy-makers need tools to identify the geographic areas where overexposure to toxic agents may be observed. The objective of the SIGFRIED 1 project is to build a work station for spatial modeling of the exposure of the French population to chemical substances and for identifying the determinants of this exposure. Probabilistic multimedia modeling is used to assess exposure. The epistemological problems associated with the absence of data are overcome by the implementation of tools that apply spatial analysis techniques. An example is furnished for the region of Nord-Pas-de-Calais and Picardie, for cadmium, nickel and lead exposure. The calculation of exposure is performed for duration of 70 years on the basis of data collected around 2004 fora grid of squares 1 km in length. For example, for Nord-Pas-de-Calais, the indicators allow us to define two areas for cadmium and three for lead. They are linked to the region's industrial history: mining basin, metallurgy activities, and the Lille metropolitan area. The contribution of various exposure pathways varied substantially from one pollutant to another. The exposure maps thus obtained allow us to identify the geographic area where environmental studies must be conducted in priority. The GIS thus constructed is the foundation of a workstation where source emission data, environmental exposure measurements, and finally health and socioeconomic measurements can be combined.

q-bio.OT↗
arXiv2014

Cybernetic Principles of Aging and Rejuvenation: the buffering-challenging strategy for life extension

Aging is analyzed as the spontaneous loss of adaptivity and increase in fragility that characterizes dynamic systems. Cybernetics defines the general regulatory mechanisms that a system can use to prevent or repair the damage produced by disturbances. According to the law of requisite variety, disturbances can be held in check by maximizing buffering capacity, range of compensatory actions, and knowledge about which action to apply to which disturbance. This suggests a general strategy for rejuvenating the organism by increasing its capabilities of adaptation. Buffering can be optimized by providing sufficient rest together with plenty of nutrients: amino acids, antioxidants, methyl donors, vitamins, minerals, etc. Knowledge and the range of action can be extended by subjecting the organism to an as large as possible variety of challenges. These challenges are ideally brief so as not to deplete resources and produce irreversible damage. However, they should be sufficiently intense and unpredictable to induce an overshoot in the mobilization of resources for damage repair, and to stimulate the organism to build stronger capabilities for tackling future challenges. This allows them to override the trade-offs and limitations that evolution has built into the organism's repair processes in order to conserve potentially scarce resources. Such acute, "hormetic" stressors strengthen the organism in part via the "order from noise" mechanism that destroys dysfunctional structures by subjecting them to strong, random variations. They include heat and cold, physical exertion, exposure, stretching, vibration, fasting, food toxins, micro-organisms, environmental enrichment and psychological challenges.

q-bio.OT↗
arXiv2014

A probabilistic model to describe the dual phenomena of biochemical pathway damage and biochemical pathway repair

Biochemical pathways emerge from a series of Brownian collisions between various types of biological macromolecules within separate cellular compartments and in highly viscous cytosol. Functioning of biochemical networks suggests that such serendipitous collisions, as a whole, result into a perfect synchronous order. Nonetheless, owing to the very nature of Brownian collisions, a small yet non-trivial probability can always be associated with the events when such synchronizations fail to emerge consistently; which account for a damage of a biochemical pathway. The repair mechanism of the system then attempts to minimize the damage, in the pursuit to bring restore the appropriate level of synchronization between reactant concentrations. Present work presents a predictive probabilistic model that describes the various facets of this complicated and coupled process(damaging and repairing). By describing the cytosolic reality of Brownian collisions with Chapman-Kolmogorov equations, the model presents analytical answers to the questions, with what probability a fragment of any pathway may suffer damage within an arbitrary interval of time? and with what probability the damage to a pathway can be repaired within any arbitrary interval of time?

q-bio.OT↗
arXiv2014

Success of Chemotherapy in Soft Matter

The success of chemotharapy in soft matter as a survival is found in the paper. Therefore, it is found the analogous tumor stretching force in soft matter; ultrasonography is performed for this tumor; restoration in soft matter with such a tumor is found; Bayes estimate of the probability of chemotherapy success is derived from the transferred chemical energy and from soft matter entropy; survival probability is juxtaposed to this probability of success.

q-bio.OT↗
arXiv2014

Social well-being of a sample of Iranian nurses: a descriptive-analytic study

Nurses social well-being deserves special attention. Effective well-being promotion strategies should be executed for promoting their social well-being particularly in areas of social integration and social acceptance. Moreover, nurses, particularly female nurses, need strong financial, emotional, informational, and social support for ensuring their social well-being.

q-bio.OT↗
arXiv2014

A Logical Framework for Systems Biology

We propose a novel approach for the formal verification of biological systems based on the use of a modal linear logic. We show how such a logic can be used, with worlds as instants of time, as an unified framework to encode both biological systems and temporal properties of their dynamic behaviour. To illustrate our methodology, we consider a model of the P53/Mdm2 DNA-damage repair mechanism. We prove several properties that are important for such a model to satisfy and serve to illustrate the promise of our approach. We formalize the proofs of these properties in the Coq Proof Assistant, with the help of a Lambda Prolog prover for partial automation of the proofs.

cs.LO↗
arXiv2014

LEDs for Energy Efficient Greenhouse Lighting

Light energy is an important factor for plant growth. In regions where the natural light source, i.e. solar radiation, is not sufficient for growth optimization, additional light sources are being used. Traditional light sources such as high pressure sodium lamps and other metal halide lamps are not very efficient and generate high radiant heat. Therefore, new sustainable solutions should be developed for energy efficient greenhouse lighting. Recent developments in the field of light source technologies have opened up new perspectives for sustainable and highly efficient light sources in the form of light-emitting diodes, i.e. LEDs, for greenhouse lighting. This review focuses on the potential of LEDs to replace traditional light sources in the greenhouse. In a comparative economic analysis of traditional vs. LED lighting, we show that the introduction of LEDs allows reduction of the production cost of vegetables in the long-run of several years, due to the high energy efficiency, low maintenance cost and longevity of LEDs. In order to evaluate LEDs as a true alternative to current lighting sources, species specific plant response to different wavelengths is discussed in a comparative study. However, more detailed scientific studies are necessary to understand the effect of different LED spectra on plants physiology. Technical innovations are required to design and realize an energy efficient light source with a spectrum tailored for optimal plant growth in specific plant species.

q-bio.OT↗