Abdominal Grey Color Variation along an Elevation Gradient in a Lizard

Color variation among populations is thought to be either due to genetic variation or phenotype plasticity.In this study,we found that an agamid lizard,Phrynocephalus theobaldi,inhabiting elevations greater than any other reptile,displayed a significantly darker spotted marking on the central ventral abdomen in higher populations than in lower populations.The grey spotted area only occurred in elevations>4200 m,and also increased with increased elevation.The ratio of the size of the dark colored area to the degree of skin luminance/reflectance was used to test whether the lizard has a larger and darker spotted area at higher elevations.This ratio was significantly positively associated with elevation rather than substrate color.The lizard did not display sexual difference in this phenotype.Temperature had a significant influence on the brightness of central abdomen,but temperature-related plasticity of this trait was much smaller than the magnitude of the difference between higher(>4200 m)and lower populations(<4200 m).Common garden experiments showed that genetic inheritance,rather than phenotype plasticity,played a dominant role in this variation.Our research addressed the darkness of a body region that is rarely analyzed because it is shielded from direct insolation.The idea that ventral color could be related to thermoregulation is shown to be worthy of further research.

Review of blue perovskite light emitting diodes with optimization strategies for perovskite film and device structure

Perovskite light emitting diodes(PeLEDs)have attracted considerable research attention because of their external quantum efficiency(EQE)of>20%and have potential scope for further improvement.However,compared to red and green PeLEDs,blue PeLEDs have not been extensively investigated,which limits their commercial applications in the fields of luminance and full-color displays.In this review,blue-PeLED-related research is categorized by the composition of perovskite.The main challenges and corresponding optimization strategies for perovskite films are summarized.Next,the novel strategies for the design of device structures of blue PeLEDs are reviewed from the perspective of transport layers and interfacial layers.Accordingly,future directions for blue PeLEDs are discussed.This review can be a guideline for optimizing perovskite film and device structure of blue PeLEDs,thereby enhancing their development and application scope.

The complete mitochondrial genome of Parachiloglanis hodgarti and its phylogenetic position within Sisoridae

The complete mitogenome of Parachiloglanis hodgarti was sequenced and characterized,which is the first mitogenome of the genus Parachiloglanis within Sisoridae.The mitogenome is 16511-bp long and included 13 protein-coding genes,22 transfer RNAs,two ribosomal RNAs,and one control region.The genome composition was A+T biased(58.64%)and exhibited a positive AT-skew(0.095)and a negative GC-skew(-0.283).Compared with other Sisoridae fishes,the characteristics of nucleotide skews,codon usage,and amino acid usage of the P.hodgarti mitogenome are more similar to those of non-Glyptosternoid fishes.Furthermore,the phylogenetic trees show that Sisoridae fishes fall into four major clades and P.hodgarti(CladeⅠ)is basal to the Sisoridae family,forming a sister clade to the Glyptosternoids(CladeⅣ).The topological structures constructed in this study raised doubts over the traditional classification system.These results will help better understand the feature s of the P.hodgarti mitogenome and provide a reference for further phylogenetic research on Sisoridae species.

New perspectives on the genetic structure of dotted gizzard shad(Konosirus punctatus)based on RAD-seq

To maintain,develop and rationally utilize marine organisms,understanding their genetic structure and habitat adaptation pattern is necessary.Konosirus punctatus,which is a commercial fish species inhabiting the Indo-west Pacific Ocean,has shown an obvious annual global capture and aquaculture production decline due to climate changes and human activities.In the present study,restriction-site associated DNA sequencing(RAD-seq)was used to describe its genome-wide single nucleotide polymorphisms panel(SNPs).Among 146 individuals collected at nine locations scattered in China,Korea and Japan,a set of 632,090 SNPs were identified.Population genetic analysis showed that K.punctatus individuals were divided into two significant genetic clusters.Meanwhile,potential genetic differentiation between northern and southern population of K.punctatus was found.Treemix results indicated that gene flow existed among sampling locations of K.punctatus,especially from southern Japan to others.Moreover,candidate genes associated with habitat adaptations of K.punctatus were identified,which are involved in diverse physiological processes of K.punctatus including growth and development(e.g.,KIDINS220,PAN3),substance metabolism(e.g.,PGM5)and immune response(e.g.,VAV3,CCT7,HSPA12B).Our findings may aid in understanding the possible mechanisms for the population genetic structure and local adaptation of K.punctatus,which is beneficial to establish the management and conservation units of K.punctatus,guiding the rational use of resources,with reference significance for a profound understanding of the adaptative mechanisms of other marine organisms to the environment.

Elevation as a selective force on mitochondrial respiratory chain complexes of the Phrynocephalus lizards in the Tibetan plateau

Animals living in extremely high elevations have to adapt to low temperatures and low oxygen availability(hypoxia),but the underlying genetic mechanisms associated with these adaptations are still unclear.The mitochondrial respiratory chain can provide>95%of the ATP in animal cells,and its efficiency is influenced by temperature and oxygen availability.Therefore,the respiratory chain complexes(RCCs)could be important molecular targets for positive selection associated with respiratory adaptation in high-altitude environments.Here,we investigated positive selection in 5 RCCs and their assembly factors by analyzing sequences of 106 genes obtained through RNA-seq of all 15 Chinese Phrynocephalus lizard species,which are distributed from lowlands to the Tibetan plateau(average elevation>4,500 m).Our results indicate that evidence of positive selec-tion on RCC genes is not significantly different from assembly factors,and we found no difference in selective pressures among the 5 complexes.We specifically looked for positive selection in line-ages where changes in habitat elevation happened.The group of lineages evolving from low to high altitude show stronger signals of positive selection than lineages evolving from high to low elevations.Lineages evolving from low to high elevation also have more shared codons under positive selection,though the changes are not equivalent at the amino acid level.This study advan-ces our understanding of the genetic basis of animal respiratory metabolism evolution in extreme high environments and provides candidate genes for further confirmation with functional analyses.

Design and optimization of fluid lubricated bearings operated with extreme working performances——a comprehensive review

Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology,semiconductor devices,aviation,strategic defense,ultraprecision manufacturing,medical treatment,and power generation.In all these applications,the equipment must deliver extreme working performances such as ultraprecise movement,ultrahigh rotation speed,ultraheavy bearing loads,ultrahigh environmental temperatures,strong radiation resistance,and high vacuum operation,which have challenged the design and optimization of reliable fluid lubricated bearings.Breakthrough of any related bottlenecks will promote the development course of high-end equipment.To promote the advancement of high-end equipment,this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances,targeting the realization of extreme working performances,current challenges and solutions,underlying deficiencies,and promising developmental directions.This paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances.

Relative vibration identification of cutter and workpiece based on improved bidimensional empirical mode decomposition

In the process of cutting,the relative vibration between the cutter and the workpiece has an important effect on the surface topography.In this study,the bidimensional empirical mode decomposition(BEMD)method is used to identify such effect.According to Riesz transform theory,a type of isotropic monogenic signal is proposed.The boundary data is extended on the basis of a similarity principle that deals with serious boundary effect problem.The decomposition examples show that the improved BEMD can effectively solve the problem of boundary effect and decompose the original machined surface topography at multiple scales.The characteristic surface topography representing the relative vibration between the cutter and the workpiece through feature identification is selected.In addition,the spatial spectrum analysis of the extracted profile is carried out.The decimal part of the frequency ratio that has an important effect on the shape of the contour can be accurately identified through contour extraction and spatial spectrum analysis.The decomposition results of simulation and experimental surface morphology demonstrate the validity of the improved BEMD algorithm in realizing the relative vibration identification between the cutter and the workpiece.