Weak Selection Research Articles

Niche Construction Affects the Variability and Strength of Natural Selection.

Consideration of the properties of the sources of selection potentially helps biologists account for variation in selection. Here we explore how the variability of natural selection is affected by organisms that regulate the experienced environment through their activities (whether by constructing components of their local environments, such as nests, burrows, or pupal cases, or by choosing suitable resources). Specifically, we test the predictions that organism-constructed sources of selection that buffer environmental variation will result in (i) reduced variation in selection gradients, including reduced variation between (a) years (temporal variation) and (b) locations (spatial variation), and (ii) weaker directional selection relative to nonconstructed sources. Using compiled data sets of 1,045 temporally replicated selection gradients, 257 spatially replicated selection gradients, and a pooled data set of 1,230 selection gradients, we find compelling evidence for reduced temporal variation and weaker selection in response to constructed compared to nonconstructed sources of selection and some evidence for reduced spatial variation in selection. These findings, which remained robust to alternative data sets, taxa, analytical methods, definitions of constructed/nonconstructed, and other tests of reliability, suggest that organism-manufactured or chosen components of environments may have qualitatively different properties from other environmental features.

Evolutionary dynamics of Chinese tourism market extremely low-priced strategies based on wright-fisher processes

Extremely low-priced of package tours is an important cause of Chinese tourism market price disorder. Regulating the price of package tours in Chinese tourism market, can solve the problem of Chinese tourism market price disorder. In order to research the reason of extremely low package tours price, consider the stochastic dynamics of N homogeneous mixed travel agency pricing strategies, and each travel agency could choose Extremely low-pricing or regular pricing. Based on Wright-Fisher processes, we obtain the dominant strategy of Extremely low-pricing and regular pricing under the weak selectivity in the package tours price setting, when the travel agency groups are finite. And then further verify these conditions by numerical simulation. The simulation shows that the Price elasticity of tourism demand, the transparency of the tourism market and the degree of government supervision strength have important effects on the stochastic evolution of package tours price setting. Reducing the demand elasticity of tourism market, increasing the transparency of the tourism market and the degree of government supervision strength can make travel agency choose regular pricing and solve chaotic of Chinese tourism market further. Therefore, this paper puts the suggestion of “two increases and one decrease” for the development of Chinese tourism market.

Cyclic voltammetry and galvanostatic effect on prepared Polypyrrole/Ni0.3Co2.7O4 for O2 electrocatalysis

Ni0.3Co2.7O4 oxide embedded Polypyrrole (Ppy) thin films were successfully synthesized over glassy carbon disk (GC) part of rotating ring disk electrode (RRDE) by two different electropolymerisation route i.e. galvanostatic (GS) and multi-cyclic voltammetry (CV), from a solution containing 0.1 mol L −1 pyrrole (Py) and 7 g L −1 of Ni0.3Co2.7O4. The Ppy electrodeposition signal has been studied by varying two parameters i.e. the oxide nanoparticles (NPs) presence and the preparation method. In addition, the obtained hybrid electrode morphology, stability especially in methanol presence, and electrocatalytic activity towards the oxygen reduction reaction (ORR) have been also investigated. The results reveal that the obtained films properties have been affected by the used route and furthermore by the oxide addition. The CV shape was maintained in the NPs presence, however the reversibility behavior was better, since the potential gap between doping/dedoping processes became closer and its corresponding currents are significantly risen. The two synthesis methods lead to hybrids electrodes with pronounced ORR electrocatalytic activity. Thus, the GS obtained material exhibits a weak selectivity regarding electrons exchanged number and the H2O2 produced amount was only about 50%. However, these interesting properties were enhanced i.e. mainly 2 electrons were exchanged by producing 96% of H2O2, when the composite electrode was prepared by CV route. Moreover, this catalyst has good stability, as well as a higher tolerance to methanol for relative long time. Therefore, the CV method can be very useful on conducting polymer/NPs materials synthesis for environmental applications requiring peroxides use.

Discordant patterns of introgression across a narrow hybrid zone between two cryptic lineages of an Iberian endemic newt.

The study of natural hybrid zones can illuminate aspects of lineage divergence and speciation in morphologically cryptic taxa. We studied a hybrid zone between two highly divergent but morphologically similar lineages (south-western and south-eastern) of the Iberian endemic Bosca's newt (Lissotriton boscai) in SW Iberia with a multilocus dataset (microsatellites, nuclear and mitochondrial genes). STRUCTURE and NEWHYBRIDS analyses retrieved few admixed individuals, which classified as backcrosses involving parental individuals of the south-western lineage. Our results show asymmetric introgression of mtDNA beyond the contact from this lineage into the south-eastern lineage. Analysis of nongeographic introgression patterns revealed asymmetries in the direction of introgression, but except for mtDNA, we did not find evidence for nonconcordant introgression patterns across nuclear loci. Analysis of a 150-km transect across the hybrid zone showed broadly coincident cline widths (ca. 3.2-27.9km), and concordant cline centres across all markers, except for mtDNA that is displaced ca. 60km northward. Results from ecological niche modelling show that the hybrid zone is in a climatically homogenous area with suitable habitat for the species, suggesting that contact between the two lineages is unlikely to occur further south as their distributions are currently separated by an extensive area of unfavourable habitat. Taken together, our findings suggest the genetic structure of this hybrid zone results from the interplay of historical (biogeographic) and population-level processes. The narrowness and coincidence of genetic clines can be explained by weak selection against hybrids and reflect a degree of reproductive isolation that is consistent with cryptic speciation.

Weak selection can filter environmental noise in the evolution of animal behavior.

Weak selection is an important assumption in theoretical evolutionary biology, but its biological significance remains unclear. In this study, we investigate the effect of weak selection on stochastic evolutionary stability in a two-phenotype evolutionary game dynamics with a random payoff matrix assuming an infinite, well-mixed population undergoing discrete, nonoverlapping generations. We show that, under weak selection, both stochastic local stability and stochastic evolutionary stability in this system depend on the means of the random payoffs but not on their variances. Moreover, although stochastic local stability or instability of an equilibrium may not depend on environmental noise if selection is weak enough, the growth rate near an equilibrium not only depends on environmental noise, but can even be enhanced by environmental noise if selection is weak. This is the case, for instance, when the variances of the random payoffs as well as the covariances are equal. These results suggest that natural selection could be able to filter (or resist) the effect of environmental noise on the evolution of animal behavior if selection is weak.

Evolutionary dynamics with game transitions

The environment has a strong influence on a population's evolutionary dynamics. Driven by both intrinsic and external factors, the environment is subject to continual change in nature. To capture an ever-changing environment, we consider a model of evolutionary dynamics with game transitions, where individuals' behaviors together with the games that they play in one time step influence the games to be played in the next time step. Within this model, we study the evolution of cooperation in structured populations and find a simple rule: Weak selection favors cooperation over defection if the ratio of the benefit provided by an altruistic behavior, b, to the corresponding cost, c, exceeds [Formula: see text], where k is the average number of neighbors of an individual and [Formula: see text] captures the effects of the game transitions. Even if cooperation cannot be favored in each individual game, allowing for a transition to a relatively valuable game after mutual cooperation and to a less valuable game after defection can result in a favorable outcome for cooperation. In particular, small variations in different games being played can promote cooperation markedly. Our results suggest that simple game transitions can serve as a mechanism for supporting prosocial behaviors in highly connected populations.

Structure-Based Pharmacophore Modeling, Virtual Screening, Molecular Docking and Biological Evaluation for Identification of Potential Poly (ADP-Ribose) Polymerase-1 (PARP-1) Inhibitors.

Poly (ADP-ribose) polymerase-1 (PARP-1) plays critical roles in many biological processes and is considered as a potential target for anticancer therapy. Although some PARP-1 inhibitors have been reported, their clinical application in cancer therapy is limited by some shortcomings such as weak affinity, low selectivity and adverse side effects. To identify highly potent and selective PARP-1 inhibitors, an integrated protocol that combines pharmacophore mapping, virtual screening and molecular docking was constructed. It was then used as a screening query to identify potent leads with unknown scaffolds from an in-house database. Finally, four retrieved compounds were selected for biological evaluation. Biological testing indicated that the four compounds showed strong inhibitory activities on the PARP-1 (IC50 < 0.2 μM). MTT assay confirmed that compounds 1–4 inhibited the growth of human lung cancer A549 cells in a dose-dependent manner. The obtained compounds from this study may be potential leads for PARP-1 inhibition in the treatment of cancer.

Effects of linear features on resource selection and movement rates of wood bison (Bison bison athabascae)

Human-mediated disturbances can lead to novel environmental features that can affect native biota beyond simple habitat loss. In boreal forests of western Canada, linear features (LFs; e.g., pipelines, seismic lines, and roads) are known to alter behaviour, movements, and interactions among species. Understanding LF impacts on native species has therefore been a management priority. Here, we investigate how LFs affect the spatial behaviour of wood bison (Bison bison athabascae Rhoads, 1898), which are designated as “threatened” in Canada. Using data collected from the Ronald Lake population in northeastern Alberta, we assessed how LFs influenced habitat selection and movement of bison by testing support among three hypotheses explaining whether LFs (i) increased forage availability, (ii) enhanced movement efficiency, or (iii) increased predation risk. Results supported the movement efficiency hypothesis as bison were generally ambivalent toward LFs, showing weak selection or avoidance depending on land-cover type, but moved slightly faster when on them. These findings contrast with avoidance behaviours reported for sympatric woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)), which are also “threatened.” Our results should inform critical habitat decisions for wood bison, but we caution that further research is needed to understand the effects of LFs on bison demography.

Occupancy Patterns in a Reintroduced Fisher Population during Reestablishment

ABSTRACTMonitoring population performance in the years following species reintroductions is key to assessing population restoration success and evaluating assumptions made in planning species restoration programs. From 2008–2010 we translocated 90 fishers (Pekania pennanti) from British Columbia, Canada, to Washington's Olympic Peninsula, USA, providing the opportunity to evaluate modeling assumptions used to identify the most suitable reintroduction areas in Washington and enhance understanding of fisher habitat associations in the late‐successional forest ecosystems in the coastal Pacific Northwest. From 2013–2016, we deployed 788 motion‐sensing cameras and hair (DNA)‐snaring devices distributed among 263 24‐km2 primary sampling units across the Olympic Peninsula. Our objectives were to determine whether occupancy patterns of the reestablishing population supported assumptions of the initial habitat assessment models, whether the population had expanded or shifted in distribution since the initial reintroductions, compare physical habitat attributes among land‐management designations, and determine whether the founding fishers had successfully reproduced. We predicted that site occupancy by fishers would be associated with landscapes characterized by high proportional coverage of dense forest canopies and medium‐sized and large trees, a diversity of stand structural classes, and area near the administrative boundary separating wilderness from more intensively managed forest lands. We detected fishers across designated wilderness, federal lands outside of wilderness, and other land designations in proportion to land availability on the Peninsula. We found negligible support for predictions that occupancy by fishers was associated with percent forest cover, tree‐size class, or structural class diversity. Rather, occupancy was strongly associated with lands near the wilderness boundary on both sides. We speculate that the boundary between wilderness and more intensively managed forest lands provided fishers with the most suitable prey in proximity to contiguous expanses of low‐ to mid‐elevation late‐successional forests that provided optimal resting, denning, and security values. Occupancy patterns shifted toward the west and south along a precipitation gradient during the study, indicating that population distribution had not yet stabilized 5–8 years following translocation. Genetic results indicated that ≥2 generations of fishers have been produced on the Peninsula. Annual occupancy rates across the Peninsula (0.08–0.24) were lower than in other previously studied and established fisher populations, indicating that not all habitat was fully occupied or that initial estimates of the extent of habitat was overestimated. The strong selection fishers exhibited for wilderness edge and weak selection against extensive forested wilderness areas suggested that habitat managers should strive for maintaining a suitable interspersion of required forest structures and biotic habitat components, such as prey resource availability. © 2019 The Wildlife Society.

Evolutionary games on isothermal graphs

Population structure affects the outcome of natural selection. These effects can be modeled using evolutionary games on graphs. Recently, conditions were derived for a trait to be favored under weak selection, on any weighted graph, in terms of coalescence times of random walks. Here we consider isothermal graphs, which have the same total edge weight at each node. The conditions for success on isothermal graphs take a simple form, in which the effects of graph structure are captured in the ‘effective degree’—a measure of the effective number of neighbors per individual. For two update rules (death-Birth and birth-Death), cooperative behavior is favored on a large isothermal graph if the benefit-to-cost ratio exceeds the effective degree. For two other update rules (Birth-death and Death-birth), cooperation is never favored. We relate the effective degree of a graph to its spectral gap, thereby linking evolutionary dynamics to the theory of expander graphs. Surprisingly, we find graphs of infinite average degree that nonetheless provide strong support for cooperation.

Evolution of Codon Usage Bias in Diatoms.

Codon usage bias (CUB)—preferential use of one of the synonymous codons, has been described in a wide range of organisms from bacteria to mammals, but it has not yet been studied in marine phytoplankton. CUB is thought to be caused by weak selection for translational accuracy and efficiency. Weak selection can overpower genetic drift only in species with large effective population sizes, such as Drosophila that has relatively strong CUB, while organisms with smaller population sizes (e.g., mammals) have weak CUB. Marine plankton species tend to have extremely large populations, suggesting that CUB should be very strong. Here we test this prediction and describe the patterns of codon usage in a wide range of diatom species belonging to 35 genera from 4 classes. We report that most of the diatom species studied have surprisingly modest CUB (mean Effective Number of Codons, ENC = 56), with some exceptions showing stronger codon bias (ENC = 44). Modest codon bias in most studied diatom species may reflect extreme disparity between astronomically large census and modest effective population size (Ne), with fluctuations in population size and linked selection limiting long-term Ne and rendering selection for optimal codons less efficient. For example, genetic diversity (pi ~0.02 at silent sites) in Skeletonema marinoi corresponds to Ne of about 10 million individuals, which is likely many orders of magnitude lower than its census size. Still, Ne ~107 should be large enough to make selection for optimal codons efficient. Thus, we propose that an alternative process—frequent changes of preferred codons, may be a more plausible reason for low CUB despite highly efficient selection for preferred codons in diatom populations. The shifts in the set of optimal codons should result in the changes of the direction of selection for codon usage, so the actual codon usage never catches up with the moving target of the optimal set of codons and the species never develop strong CUB. Indeed, we detected strong shifts in preferential codon usage within some diatom genera, with switches between preferentially GC-rich and AT-rich 3rd codon positions (GC3). For example, GC3 ranges from 0.6 to 1 in most Chaetoceros species, while for Chaetoceros dichaeta GC3 = 0.1. Both variation in selection intensity and mutation spectrum may drive such shifts in codon usage and limit the observed CUB. Our study represents the first genome-wide analysis of CUB in diatoms and the first such analysis for a major phytoplankton group.

Protective Effect of RIVA Against Sunitinib-Induced Cardiotoxicity by Inhibiting Oxidative Stress-Mediated Inflammation: Probable Role of TGF-β and Smad Signaling.

Sunitinib (SUN) is an oral tyrosine kinase inhibitor approved in 2006 as a first-line treatment for metastatic renal cell cancer. However, weak selectivity to kinase receptors and cardiotoxicity have limited the use of sunitinib. Rivaroxaban (RIVA) is a Factor Xa inhibitor with cardioprotective action. It inhibits atherosclerosis and numerous inflammatory cascades. The present study was designed to investigate the cardioprotective effects of RIVA in sunitinib-induced cardiotoxicity. Thirty male Wistar rats were divided into five groups. Group 1 was the normal control (control). Group 2 was administered i.p. SUN 25mgkg-1 thrice weekly for 3weeks. Groups 3 and 4 received the same treatment as Group 2 followed by the administration of RIVA 5mgkg-1 day-1 and 10mgkg-1 day-1, respectively, for 3weeks. Group 5 received only 10mgkg-1 day-1 RIVA for 3weeks. Serum levels of Ca2+, Mg2+, Fe3+/Fe2+, lipid profiles, and cardiac enzymes were measured. Cardiac tissues were isolated for the measurements of oxidant/antioxidant balance gene and protein expressions. Relative to the controls, the administration of SUN significantly altered serum levels of (Ca2+, Mg2+, Fe3+/Fe2+, lipid profiles, and cardiac enzymes), intracellular antioxidant enzymes, and the expression levels of the genes encoding certain proteins. RIVA treatment significantly restored these parameters to near-normal levels. RIVA treatment significantly mitigated SUN-induced cardiac injuries by restoring antioxidant enzyme levels and attenuating the proinflammatory cascades resulting from SUN-induced cardiac injuries.

Evidence for adaptive introgression of exons across a hybrid swarm in deer

BackgroundSecondary contact between closely related lineages can result in a variety of outcomes, including hybridization, depending upon the strength of reproductive barriers. By examining the extent to which different parts of the genome introgress, it is possible to infer the strength of selection and gain insight into the evolutionary trajectory of lineages. Following secondary contact approximately 8000 years ago in the Pacific Northwest, mule deer (Odocoileus hemionus hemionus) and black-tailed deer (O. h. columbianus) formed a hybrid swarm along the Cascade mountain range despite substantial differences in body size (up to two times) and habitat preference. In this study, we examined genetic population structure, extent of introgression, and selection pressures in freely interbreeding populations of mule deer and black-tailed deer using mitochondrial DNA sequences, 9 microsatellite loci, and 95 SNPs from protein-coding genes.ResultsWe observed bi-directional hybridization and classified approximately one third of the 172 individuals as hybrids, almost all of which were beyond the F1 generation. High genetic differentiation between black-tailed deer and mule deer at protein-coding genes suggests that there is positive divergent selection, though selection on these loci is relatively weak. Contrary to predictions, there was not greater selection on protein-coding genes thought to be associated with immune function and mate choice. Geographic cline analyses were consistent across genetic markers, suggesting long-term stability (over hundreds of generations), and indicated that the center of the hybrid swarm is 20-30 km to the east of the Cascades ridgeline, where there is a steep ecological transition from wet, forested habitat to dry, scrub habitat.ConclusionsOur data are consistent with a genetic boundary between mule deer and black-tailed deer that is porous but maintained by many loci under weak selection having a substantial cumulative effect. The absence of clear reproductive barriers and the consistent centering of geographic clines at a sharp ecotone suggests that ecology is a driver of hybrid swarm dynamics. Adaptive introgression in this study (and others) promotes gene flow and provides valuable insight into selection strength on specific genes and the evolutionary trajectory of hybridizing taxa.

Underwater Acoustic Sparse Channel Estimation Based on DW-SACoSaMP Reconstruction Algorithm

The compressive sampling matching pursuit (CoSaMP) algorithm is widely used in orthogonal frequency division multiplexing (OFDM) underwater acoustic (UWA) sparse channel estimation with good estimation accuracy. However, the algorithm requires channel sparsity a priori information as well as a large number of columns in the measurement matrix because of the large delay of the UWA channel during channel estimation, which greatly increases the complexity of CoSaMP. Therefore, a sparsity adaptive CoSaMP based on a dynamic threshold and weak selection of atoms (DW-SACoSaMP) is proposed in this letter. The algorithm can quickly estimate the channel impulse response (CIR) without channel sparsity when used for UWA sparse channel estimation. Simulation results show that, compared with other reconstruction algorithms, the estimation accuracy of this algorithm is higher and the complexity is lower; when the signal to noise ratio (SNR) is greater than 8dB, the advantage of estimation accuracy is more obvious.

Amidoxime Functionalization of Algal/Polyethyleneimine Beads for the Sorption of Sr(II) from Aqueous Solutions.

There is a need for developing new sorbents that incorporate renewable resources for the treatment of metal-containing solutions. Algal-polyethyleneimine beads (APEI) (reinforced with alginate) are functionalized by grafting amidoxime groups (AO-APEI). Physicochemical characteristics of the new material are characterized using FTIR, XPS, TGA, SEM, SEM-EDX, and BET. AO-APEI beads are tested for the recovery of Sr(II) from synthetic solutions after pH optimization (≈ pH 6). Uptake kinetics is fast (equilibrium ≈ 60–90 min). Sorption isotherm (fitted by the Langmuir equation) shows remarkable sorption capacity (≈ 189 mg Sr g−1). Sr(II) is desorbed using 0.2 M HCl/0.5 M CaCl2 solution; sorbent recycling over five cycles shows high stability in terms of sorption/desorption performances. The presence of competitor cations is studied in relation to the pH; the selectivity for Sr(II) is correlated to the softness parameter. Finally, the recovery of Sr(II) is carried out in complex solutions (seawater samples): AO-APEI is remarkably selective over highly concentrated metal cations such as Na(I), K(I), Mg(II), and Ca(II), with weaker selectivity over B(I) and As(V). AO-APEI appears to be a promising material for selective recovery of strontium from complex solutions (including seawater).

When Do Individuals Maximize Their Inclusive Fitness?

Adaptation is often described in behavioral ecology as individuals maximizing their inclusive fitness. Under what conditions does this hold, and how does this relate to the gene-centered perspective of adaptation? We unify and extend the literature on these questions to class-structured populations. We demonstrate that the maximization (in the best-response sense) of class-specific inclusive fitness obtains in uninvadable population states (meaning that all deviating mutants become extinct). This defines a genuine actor-centered perspective on adaptation. But this inclusive fitness is assigned to all bearers of a mutant allele in a given class and depends on distributions of demographic and genetic contexts. These distributions, in turn, usually depend on events in previous generations and are thus not under individual control. This prevents, in general, envisioning individuals themselves as autonomous fitness maximizers, each with its own inclusive fitness. For weak selection, however, the dependence on earlier events can be neglected. We then show that each individual in each class appears to maximize its own inclusive fitness when all other individuals exhibit inclusive fitness-maximizing behavior. This defines a genuine individual-centered perspective of adaptation and justifies formally, as a first-order approximation, the long-heralded view of individuals appearing to maximize their own inclusive fitness.

Are the better cooperators dormant or quiescent?

Despite the wealth of empirical and theoretical studies, the origin and maintenance of cooperation is still an evolutionary riddle. In this context, ecological life-history traits which affect the efficiency of selection may play a role despite being often ignored. We consider here species such as bacteria, fungi, invertebrates and plants which exhibit resting stages in the form of a quiescent state or a seed bank. When quiescent, individuals are inactive and reproduce upon activation, while under seed bank parents produce offspring remaining dormant for different amount of time. We assume weak frequency-dependent selection modeled using game-theory and the prisoner’s dilemma (cooperation/defect) as payoff matrix. The cooperators and defectors are allowed to evolve different quiescence or dormancy times. By means of singular perturbation theory we reduce the model to a one-dimensional equation resembling the well known replicator equation, in which the gain functions are scaled with lumped parameters reflecting the time scale of the resting state of the cooperators and defectors. If both time scales are identical cooperation cannot persist in a homogeneous population. If, however, the time scale of the cooperator is distinctively different from that of the defector, cooperation may become a locally asymptotically stable strategy. Interestingly enough, in the seed bank case the cooperator needs to become active faster than the defector, while in the quiescent case the cooperator has to be slower. We use adaptive dynamics to identify situations where cooperation may evolve and form a convergent stable ESS. We conclude by highlighting the relevance of these results for many non-model species and the maintenance of cooperation in microbial, invertebrate or plant populations.

Cross PHY/APP Layer User Grouping and Power Allocation for Uplink Multiantenna NOMA Video Communication Systems

The previous suboptimal user pairing and optimal power control for uplink multiantenna NOMA systems considers the physical-layer-only to maximize the sum data rates. For video communications, the objective is changed to minimize the sum video distortion and then maximize the peak signal-to-noise ratio (PSNR). For uplink multiantenna NOMA systems, we propose 1) a novel weak set user selection scheme to maximize the ratio of signal power and the interference to the strong set users, 2) a novel iterative user substitution scheme based on video distortion in the application layer that increases the PSNR, and the video quality, 3) a novel optimal power allocation derived to minimize the video distortion in the application layer. 1) considers the physical-layer only and 2) and 3) consider the application layer too. The numerical results indicate that the proposed cross-layer scheme outperforms the previous physical-layer-only by 1.1 dB, and is only 0.8 dB away from the exhaustive upper bound in PSNR with 20 users and SNR = 15 dB. The complexity of the proposed scheme is slightly greater than that of the previous physical-layer-only scheme, but still much lower than that of the exhaustive upper bound.

Nanotetrahedron-assisted electrochemical aptasensor with cooperatively-folding aptamer chimera for sensitive and selective detection of lysozyme in red wines

Although aptamers show great potential in the field of analytical chemistry, their intrinsic shortcomings of relatively weak affinity and selectivity in complex working environment limit their applicability to real analysis, because the flexibility of aptamers makes the specific aptatopes (i.e., binding sites for targets) in the conformational structure unstable and deficient. Herein, an anti-lysozyme aptamer and lysozyme were chosen as models. An aptamer chimera which could cooperatively fold to provide stable aptatopes for lysozyme was designed for improvement of the anti-lysozyme aptamers’ recognition ability, and an electrochemical aptasensor was then developed based on the aptamer chimera, with assistance of a rigid DNA nanotetrahedron as a spacer to orientate the aptamer chimera on the electrodes. The nanotetrahedron-aptamer chimera-based aptasensor presented highly sensitive and selective detection towards lysozyme in red wines, furnishing a 42-fold lower LOD (17.9 pmol L−1) and better selectivity than that of the aptasensor with the original aptamer. Moreover, the developed aptasensor was characterized by good recovery (91.3–109.0%), good accuracy, repeatability and stability, indicating the excellent practical applicability of the cooperatively-folding aptamer chimera in real world. This proof-of-concept study can be referred for any other aptamers, analytes, and samples.

Acoustic-resonance method for control of the location of hidden hollow objects

There are quite a number of methods for monitoring the location of buried pipelines: radio wave method, radiation method, acoustic location, resonant-acoustic profiling, infrared thermography, electromagnetic method.However, these methods have several disadvantages: they are not applicable to pipelines of non-metallic materials, and also have a weak selectivity in controlling the location of buried pipelines when many different communications pass in close proximity to the object under control.In this work, an improved acoustic-resonance method for controlling the location of hidden hollow objects has been developed and implemented as an information-measuring complex consisting of devices for exciting and receiving forced vibrations. The algorithmic and software-technical support of the processes of controlling the information-measuring complex and processing of vibroacoustic signals in the LabVIEW environment has been developed and created.