Read by QxMD icon Read

Neutral evolution

Sengeni Anantharaj, Jeevarathinam Kennedy, Subrata Kundu
Molecular hydrogen (H2) generation through water splitting with minimum energy loss has become practically possible due to the recent evolution of high performance electrocatalysts. In this study, we had fabricated, evaluated and presented such a high performance catalyst which is the Ni3Se4 nanoassemblies that can efficiently catalyze water splitting in neutral and alkaline media. A hierarchical nanoassemblies of Ni3Se4 was fabricated by functionalizing the surface cleaned Ni foam using NaHSe solution as Se source with the assistance of microwave irradiation (300 W) for 3 min followed by 5 h of aging at room temperature (RT)...
February 20, 2017: ACS Applied Materials & Interfaces
Bahram Houchmandzadeh
The advent of modern genome sequencing techniques allows for a more stringent test of the neutrality hypothesis of Darwinian evolution, where all individuals have the same fitness. Using the individual-based model of Wright and Fisher, we compute the amplitude of neutral aggregation in the genome space, i.e., the probability of finding two individuals at genetic (Hamming) distance k as a function of the genome size L, population size N, and mutation probability per base ν. In well-mixed populations, we show that for Nν<1/L, neutral aggregation is the dominant force and most individuals are found at short genetic distances from each other...
January 2017: Physical Review. E
Melissa K Ha, Christopher T Ivey
PREMISE OF THE STUDY: Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. METHODS: We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C...
February 15, 2017: American Journal of Botany
Francesca Merlin, Livio Riboli-Sasco
The current debate over extending inheritance and its evolutionary impact has focused on adding new categories of non-genetic factors to the classical transmission of DNA, and on trying to redefine inheritance. Transmitted factors have been mainly characterized by their directions of transmission (vertical, horizontal, or both) and the way they store variations. In this paper, we leave aside the issue of defining inheritance. We rather try to build an evolutionary conceptual framework that allows for tracing most, if not all forms of transmission and makes sense of their different tempos and modes...
February 14, 2017: Acta Biotheoretica
Carlos Y Valenzuela
Direct tests of the random or non-random distribution of nucleotides on genomes have been devised to test the hypothesis of neutral, nearly-neutral or selective evolution. These tests are based on the direct base distribution and are independent of the functional (coding or non-coding) or structural (repeated or unique sequences) properties of the DNA. The first approach described the longitudinal distribution of bases in tandem repeats under the Bose-Einstein statistics. A huge deviation from randomness was found...
February 13, 2017: Biological Research
Kyle E Ballantine, Benjamin L Lev, Jonathan Keeling
Previous realizations of synthetic gauge fields for ultracold atoms do not allow the spatial profile of the field to evolve freely. We propose a scheme which overcomes this restriction by using the light in a multimode cavity with many nearly degenerate transverse modes, in conjunction with Raman coupling, to realize an artificial magnetic field which acts on a Bose-Einstein condensate of neutral atoms. We describe the evolution of such a system and present the results of numerical simulations which show dynamical coupling between the effective field and the matter on which it acts...
January 27, 2017: Physical Review Letters
Michael S Reichert, Jonas Finck, Bernhard Ronacher
A major challenge in evolutionary biology is explaining the origins of complex phenotypic diversity. In animal communication, complex signals may evolve from simpler signals because novel signal elements exploit pre-existing biases in receivers' sensory systems. Investigating the shape of female preference functions for novel signal characteristics is a powerful, but underutilized, method to describe the adaptive landscape potentially guiding complex signal evolution. We measured female preference functions for characteristics of acoustic appendages added to male calling songs in the grasshopper Chorthippus biguttulus, which naturally produces only simple songs...
February 10, 2017: Evolution; International Journal of Organic Evolution
Samatha Bevara, S Nagabhusan Achary, Karuna Kara Mishra, T R Ravindran, Anil K Sinha, P U Sastry, Avesh Kumar Tyagi
Herein we report the evolution of the crystal structure of K3Gd5(PO4)6 in the temperature range from 20 K to 1073 K, as observed from variable temperature X-ray diffraction and Raman spectroscopic studies. K3Gd5(PO4)6 has an open tunnel containing a three dimensional structure built by [Gd5(PO4)6](3-) ions which in turn are formed of PO4 tetrahedra and GdOn (n = 8 and 9) polyhedra. The empty tunnels in the structure are occupied by K(+) ions and maintain charge neutrality in the lattice. Evolution of unit cell parameters with temperature shows a systematic increase with temperature...
February 10, 2017: Physical Chemistry Chemical Physics: PCCP
Reed A Cartwright, Rachel S Schwartz, Alexandra L Merry, Megan M Howell
BACKGROUND: Blindness has evolved repeatedly in cave-dwelling organisms, and many hypotheses have been proposed to explain this observation, including both accumulation of neutral loss-of-function mutations and adaptation to darkness. Investigating the loss of sight in cave dwellers presents an opportunity to understand the operation of fundamental evolutionary processes, including drift, selection, mutation, and migration. RESULTS: Here we model the evolution of blindness in caves...
February 7, 2017: BMC Evolutionary Biology
Bibhuti Bhusan Sahu, Jeon Geon Han, Holger Kersten
Understanding the science and engineering of thin films using plasma assisted deposition methods with controlled growth and microstructure is a key issue in modern nanotechnology, impacting both fundamental research and technological applications. Different plasma parameters like electrons, ions, radical species and neutrals play a critical role in nucleation and growth and the corresponding film microstructure as well as plasma-induced surface chemistry. The film microstructure is also closely associated with deposition energy which is controlled by electrons, ions, radical species and activated neutrals...
February 7, 2017: Physical Chemistry Chemical Physics: PCCP
Tofik Ahmed Shifa, Fengmei Wang, Kaili Liu, Zhongzhou Cheng, Kai Xu, Zhenxing Wang, Xueying Zhan, Chao Jiang, Jun He
The rational design of Earth abundant electrocatalysts for efficiently catalyzing hydrogen evolution reaction (HER) is believed to lead to the generation of carbon neutral energy carrier. Owing to their fascinating chemical and physical properties, transition metal dichalcogenides (TMDs) are widely studied for this purpose. Of particular note is that doping by foreign atom can bring the advent of electronic perturbation, which affects the intrinsic catalytic property. Hence, through doping, the catalytic activity of such materials could be boosted...
February 6, 2017: Small
Laura R Delgui, María I Colombo
Viruses are lifeless particles designed for setting virus-host interactome assuring a new generation of virions for dissemination. This interactome generates a pressure on host organisms evolving mechanisms to neutralize viral infection, which places the pressure back onto virus, a process known as virus-host cell co-evolution. Positive-single stranded RNA (+sRNA) viruses are an important group of viral agents illustrating this interesting phenomenon. During replication, their genomic +sRNA is employed as template for translation of viral proteins; among them the RNA-dependent RNA polymerase (RdRp) is responsible of viral genome replication originating double-strand RNA molecules (dsRNA) as intermediates, which accumulate representing a potent threat for cellular dsRNA receptors to initiate an antiviral response...
2017: Frontiers in Cellular and Infection Microbiology
Pia Bükmann Larsen, Elin Storjord, Åsne Bakke, Tone Bukve, Mikael Christensen, Joakim Eikeland, Vegar Engeland Haugen, Kristin Husby, Rie McGrail, Solveig Meier Mikaelsen, Grete Monsen, Mette Fogh Møller, Jan Nybo, Jesper Revsholm, Aslaug Johanne Risøy, Unni Marie Skålsvik, Heidi Strand, Reyes Serrano Teruel, Elvar Theodorsson
Regular measurement of prothrombin time as an international normalized ratio PT (INR) is mandatory for optimal and safe use of warfarin. Scandinavian evaluation of laboratory equipment for primary health care (SKUP) evaluated the microINR portable coagulometer (microINR(®)) (iLine Microsystems S.L., Spain) for measurement of PT (INR). Analytical quality and user-friendliness were evaluated under optimal conditions at an accredited hospital laboratory and at two primary health care centres (PHCCs). Patients were recruited at the outpatient clinic of the Laboratory of Medical Biochemistry, St Olav's University Hospital, Trondheim, Norway (n = 98) and from two PHCCs (n = 88)...
April 2017: Scandinavian Journal of Clinical and Laboratory Investigation
M Ji, J Bernard, L Chen, R Brédy, C Ortéga, C Joblin, A Cassimi, S Martin
We report on a direct measurement of the Internal Energy Distribution (IED) shift rate of an initially hot polycyclic aromatic hydrocarbon (PAH) molecular ensemble, anthracene cations (C14H10(+)). The ions were produced in an electron cyclotron resonance (ECR) ion source and stored in an electrostatic ion storage ring, the Mini-Ring. Laser pulses of two wavelengths were sent successively to merge the stored ion bunch at different storage times to enhance the neutral fragment yield due to fast laser induced dissociation...
January 28, 2017: Journal of Chemical Physics
Shenshen Wang
Affinity maturation is a Darwinian process in which B lymphocytes evolve potent antibodies to encountered antigens and generate immune memory. Highly mutable complex pathogens present an immense antigenic diversity that continues to challenge natural immunity and vaccine design. Induction of broadly neutralizing antibodies (bnAbs) against this diversity by vaccination likely requires multiple exposures to distinct but related antigen variants, and yet how affinity maturation advances under such complex stimulation remains poorly understood...
January 2017: PLoS Computational Biology
Mattia Bonsignori, Hua-Xin Liao, Feng Gao, Wilton B Williams, S Munir Alam, David C Montefiori, Barton F Haynes
Induction of HIV-1 broadly neutralizing antibodies (bnAbs) to date has only been observed in the setting of HIV-1 infection, and then only years after HIV transmission. Thus, the concept has emerged that one path to induction of bnAbs is to define the viral and immunologic events that occur during HIV-1 infection, and then to mimic those events with a vaccine formulation. This concept has led to efforts to map both virus and antibody events that occur from the time of HIV-1 transmission to development of bnAbs...
January 2017: Immunological Reviews
S S Ling, Y Zhu, D Lan, D S Li, H Z Pang, Y Wang, D Y Li, R P Wei, H M Zhang, C D Wang, Y D Hu
The giant panda, Ailuropoda melanoleuca (Ursidae), has a unique bamboo-based diet; however, this low-energy intake has been sufficient to maintain the metabolic processes of this species since the fourth ice age. As mitochondria are the main sites for energy metabolism in animals, the protein-coding genes involved in mitochondrial respiratory chains, particularly cytochrome c oxidase subunit II (COX2), which is the rate-limiting enzyme in electron transfer, could play an important role in giant panda metabolism...
January 23, 2017: Genetics and Molecular Research: GMR
Rintaro Takahashi, Theyencheri Narayanan, Takahiro Sato
We have monitored the kinetic process of polyelectrolyte complex formation between sodium polyacrylate (SPA) and polyallylamine hydrochrolide (PAH) in aqueous NaCl solution by time-resolved ultra-small-angle X-ray scattering (TR-USAXS) combined with rapid mixing. SPA and PAH with different NaCl concentrations from 0 to 1 M were rapidly mixed in equimolar concentration of the monomer units using a stopped-flow apparatus with a dead time of about 2.5 ms. Within the dead time, percolated aggregate-like structures were observed suggesting that the initially formed small charge neutral aggregates further assembled to form higher order agglomerates...
January 30, 2017: Journal of Physical Chemistry Letters
Anders Forsman, Hanna Berggren
Spatial sorting is a process that can contribute to microevolutionary change by assembling phenotypes through space, owing to nonrandom dispersal. Here we first build upon and develop the "neutral" version of the spatial sorting hypothesis by arguing that in systems that are not characterized by repeated range expansions, the evolutionary effects of variation in dispersal capacity and assortative mating might not be independent of but interact with natural selection. In addition to generating assortative mating, variation in dispersal capacity together with spatial and temporal variation in quality of spawning area is likely to influence both reproductive success and survival of spawning migrating individuals, and this will contribute to the evolution of dispersal-enhancing traits...
January 2017: Ecology and Evolution
Alexander Davis, Ruli Gao, Nicholas Navin
Intratumor heterogeneity has been widely reported in human cancers, but our knowledge of how this genetic diversity emerges over time remains limited. A central challenge in studying tumor evolution is the difficulty in collecting longitudinal samples from cancer patients. Consequently, most studies have inferred tumor evolution from single time-point samples, providing very indirect information. These data have led to several competing models of tumor evolution: linear, branching, neutral and punctuated. Each model makes different assumptions regarding the timing of mutations and selection of clones, and therefore has different implications for the diagnosis and therapeutic treatment of cancer patients...
January 18, 2017: Biochimica et Biophysica Acta
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"