Tail Part Research Articles

Minimum Rényi entropy portfolios

Accounting for the non-normality of asset returns remains one of the main challenges in portfolio optimization. In this paper, we tackle this problem by assessing the risk of the portfolio through the “amount of randomness” conveyed by its returns. We achieve this using an objective function that relies on the exponential of Renyi entropy, an information-theoretic criterion that precisely quantifies the uncertainty embedded in a distribution, accounting for higher-order moments. Compared to Shannon entropy, Renyi entropy features a parameter that can be tuned to play around the notion of uncertainty. A Gram–Charlier expansion shows that it controls the relative contributions of the central (variance) and tail (kurtosis) parts of the distribution in the measure. We further rely on a non-parametric estimator of the exponential Renyi entropy that extends a robust sample-spacings estimator initially designed for Shannon entropy. A portfolio-selection application illustrates that minimizing Renyi entropy yields portfolios that outperform state-of-the-art minimum-variance portfolios in terms of risk-return-turnover trade-off. We also show how Renyi entropy can be used in risk-parity strategies.

Aerodynamics of the turbulent flow around a multi­element airfoil in cruse configuration and in takeoff and landing configuration

Numerical modeling of multi-element airfoil's aerodynamics employs the Reynolds averaged Navier-Stokes equations of incompressible environment, which are related via a single-parametric differential turbulence model by Spalart-Allmaras. The system of initial equations has been recorded with respect to an arbitrary curvilinear coordinate system. The pressure and velocity fields have been aligned by using an artificial compressibility method modified for calculating the nonstationary problems. The system of initial equations has been integrated numerically by applying a control volume method. The counter-flow Rogers-Kwak approximation has been used for convection flows, based on the Roe scheme of third-order accuracy. The turbulence models, in order to approximate the convection components, employed a TVD scheme with the third-order flow limiter ISNAS. The paper reports results from calculating a turbulent flow around a multi-element airfoil in a wide range of the angles of attack. The result of the current research is the performed analysis of the flow field around a multi-element airfoil, pressure coefficients, the lifting force, as well as the drag force. Physical features in a flow structure at flowing around the multi-element airfoil 30P30N have been identified. In the investigated range of the angles of attack, flowing around a airfoil in the takeoff and landing configuration is stationary in nature except for the regions where the flow is detached from sharp edges, such as the slat's inside part and a region in the tail part of the main profile. There are recirculation currents within these regions. With an increase in the angle of attack, dimensions of the detachable zone at the slat's inner surface decrease while remaining almost unchanged in the tail part of the main profile. At the top surface of the main profile there forms a jet of air, due to the acceleration of the flow between the slat and the leading edge of the main profile. The existence of a gap between the main profile and the flap leads to the interference of jet currents at the upper surface of the slat. It has been shown that the takeoff and landing configuration demonstrates the higher values of the lifting force coefficient than the cruise configuration, especially at large angles of attack. The calculation results agree well with the data by other authors.

Effects of Fe3+ on Acute Toxicity and Regeneration of Planarian (Dugesia japonica) at Different Temperatures

Objective To investigate the effects of different concentrations of Fe3+ on the acute toxicity and regeneration of planarian at different temperatures. Method The planarians were treated with 40 mg/l, 50 mg/l, 60 mg/l, and 70 mg/l Fe3+ solution and placed in 15°C, 20°C, and 25°C, respectively, to observe the mortality and the poisoning pattern of the planarian. In addition, the planarians were cut into three parts of head, trunk, and tail, then placed in Fe3+ solution at concentrations of 10 mg/l, 15 mg/l, 20 mg/l, and 30 mg/l, and placed in 15°C, 20°C, and 25°C respectively, and the regeneration rate of the planarian was investigated. Results At the same temperature, in the concentration of Fe3+ from 40 mg/l to 70 mg/l, the mortality of the planarian increased with the increasing of the concentration of Fe3+; at the same concentration and different temperatures, the death speed of the planarian is the fastest at 20°C, the next at 25°C, and the lowest at 15°C, indicating that the toxic effect of Fe3+ can be accelerated at a suitable temperature of 20°C. At the same temperature, in the low concentration of Fe3+ from 10 mg/l to 30 mg/l, the regeneration rate of the planarian gradually decreased with the increasing of the concentration of Fe3+; at the same concentration and different temperature, the regeneration rate of planarian was faster at 20°C and 25°C, but the difference between 20°C and 25°C was small, and the slowest at 15°C, indicating that the low temperature significantly affects the planarian regeneration speed. The study also found the regeneration rates of the head, trunk, and tail of the planarian were different; the head regeneration was the fastest, the trunk was the second, and the tail was the slowest. Conclusion Fe3+ had obvious toxic effects on the survival and regeneration of planarian; the planarian is sensitive to Fe3+ and may be used to detect Fe3+ water pollution; in addition, temperature can affect the toxic effects of Fe3+ and thus affect the survival and regeneration of the planarian. Therefore, the temperature should be taken into consideration when detecting water Fe3+ pollution.

Non-Gaussian Features of Local Wind Pressure for Typical Gable Roof of Low-rise Building

The non-Gaussian characteristics of local wind pressure of typical gable roof of low-rise building with a slop angle of 18.4° were monitored by means of the wind tunnel test under terrain roughness regimes of A,B and C. The probability density distribution features of wind pressure coefficient series are investigated, the characteristics of non-Gaussian zones distribution of wind pressure relative to different wind angles and different terrain conditions are analyzed and the relationships between non-Gaussian pressure and distinctions of flow field on roof are discussed. The studying results indicate that GEV distribution and Gamma distribution fit the probability density distribution of wind pressure coefficient better than Gaussian distribution and Lognormal distribution, but the fitting effect for long trailing tail part is undesirable, when skewness and kurtosis are large in magnitude (absolute value). The variation of terrain roughness and wind directions have significant influence on the distribution of non-Gaussian pressure regions on low-rise building roof. Under the oblique wind direction, the Gaussian pressure zone is divided into three sections along the approaching wind direction, along which the areas move with the change of terrain roughness regimes. The non-Gaussian features of wind pressure is positively related to mutual correlation coefficient of it’s time-history.

Evaluation and analysis on the green development of China's industrial parks using the long-tail effect model

Industrial parks (IPs) have always been an important driving force for China's economic development. China has a great number of IPs, and this number is continuing to increase. The rapid development of IPs has brought great pressure on national resources utilization and environmental protection. The Chinese government has committed to the green development of IPs. In recent years, a series of policies on the green development of IPs have been introduced and implemented. Different from the limitation on the number of IPs in previous studies, this study used a larger data set containing 911 IPs. These IPs were divided into eight types according to their leading industries. The long-tail effect model was attempted to be used to provide quantitative description and analysis of the numerical distribution patterns of the indicators of economic output, environmental pollution, and resource consumption in IPs. Based on the long-tail effect model, for this paper, the performance of green development (PGD) in different types of IPs and IPs in different regions was further analyzed. The results show that China's IPs exhibit the distribution pattern of a long-tail effect in all three aspects mentioned above. In terms of environmental pollution, for some types of IPs, the individual performance of IPs in the head part of the model is more prominent. For other types of IPs, the cumulative results caused by IPs in the tail part of the model should be of concern. The PGD of IPs is closely related to their types. There are also obvious differences in the PGD of IPs in eastern and western China. Based on detailed discussion of the research results, at the end, policy implications are provided for the government to make decisions on the green development of IPs.

Changes on the viral capsid surface during the evolution of porcine circovirus type 2 (PCV2) from 2009 till 2018 may lead to a better receptor binding.

Porcine circovirus type 2 (PCV2) is the primary causative agent of porcine circovirus-associated diseases (PCVAD). Three major PCV2 genotypes (PCV2a, PCV2b, and PCV2d) have been identified globally. Despite their worldwide distribution, the prevalence and genetic evolution of PCV2 in Belgium has not previously been determined. In this study, 319 samples from animals suffering from diseases likely to be associated with PCV2 were collected from 2009 to 2018 and analysed by virus titration. The overall prevalence of PCV2 in PCVAD-suspected cases was 15.7 per cent (50/319). The phylogenetic analysis demonstrated that at least three genotypes (PCV2a, PCV2b, and PCV2d) circulated in Belgium from 2009 till 2018, and that PCV2 evolved from PCV2a to PCV2b and from PCV2d-1 to PCV2d-2. Sequence comparison among the forty-three PCV2 isolates showed that they had 89.7–100 per cent nucleotide-sequence and 88.5–100 per cent amino-acid-sequence identities. Three amino acid sites were under positive selection. Three-dimensional analysis of genotype-specific amino acids revealed that most of the mutations were on the outside of the cap protein with a few conserved mutations present on the inner side. Mutations toward more basic amino acids were found on the upper and tail parts of two connecting capsid proteins which form one big contact region, most probably involved in receptor binding. The lower part was relatively conserved. This polarity change together with the formation of an extruding part drive the virus to a more efficient GAG receptor binding. Taken together, these results showed a genotype shift from PCV2a to PCV2b and later on from PCV2d-1 to PCV2d-2, and a PCV2 evolution toward a better receptor binding capacity.

Multifractal analysis for core-periphery structure of complex networks

Revealing the properties of the core-periphery structure of complex networks can help us to deeply understand their organized principle and function. Studies in recent years have indicated that the k-core and peripheral subnetworks of some model and real-world networks exhibit the fractal behavior, but it remains unclear whether they possess the multifractal behavior. In this paper, we study the multifractal property of these networks and their subnetworks. First, we obtain the sequence of k-cores and their corresponding k-peripheries of original networks by using the k-core decomposition method. We find that the multifractal property exists in these k-cores and k-peripheries of the generalized minimal model network and some Brain networks. Furthermore, the multifractality of the k-cores becomes weaker and that of k-peripheries becomes stronger with the increase of k. The result is consistent with the fact that the k-core becomes more homogenous or cohesive with increasing k. Then we decompose each of these original networks into a densely connected core and a sparsely connected periphery. Although the periphery and the original network have almost the same fractal behavior at the tail part of the resulting curves in the log–log plot for some fractal networks, their multifractality are very different. This means that a unique fractal dimension is not enough to characterize the complexity or spatial heterogeneity of these networks when they take a multifractal structure. Our results show that the multifractal analysis is more powerful than the fractal analysis in characterizing the complexity of the core-periphery structure of complex networks.

Electronic Property and Negative Thermal Expansion Behavior of Si136-xGex (x = 8, 32, 40, 104) Clathrate Solid Solution from First Principles.

We present the electronic and vibrational studies on Si136-xGex (x = 8, 32, 40, 104) alloys, using the local density approximation (LDA) scheme. We find that a “nearly-direct” band gap exists in the band structure of Si104Ge32 and Si96Ge40, when compared with the similarly reported results obtained using a different computational code. The calculated electronic density of state (EDOS) profiles for the valence band remain nearly identical and independent of the Ge concentration (x = 32, 40, 104) even though some variation is found in the lower conduction band (tail part) as composition x is tuned from 8 (or 40) to 104. The negative thermal expansion (NTE) phenomenon is explored using quasi-harmonic approximation (QHA), which takes the volume dependence of the vibrational mode frequencies into consideration, while neglecting the temperature effect on phonon anharmonicity. Determined macroscopic Grüneisen parameter trends show negative values in the low temperature regime (1 K < T < 115 K), indicating the NTE behavior found in Si128Ge8 is analogous to the experimental result for Si136. Meanwhile, calculations for the ratio of the vibrational entropy change to the volume change at several characteristic temperatures reconfirm the existence of NTE in Si128Ge8 and Si104Ge32.

Phototoxicity Generated by Silicon Quantum Dot Nanoparticles on Zebrafish Embryos.

We demonstrate phototoxicity generated by silicon quantum dot nanoparticles (SiQDNPs) using zebrafish as an animal model. Having long exciton lifetime, the SiQDNPs can function as photosensitizers which absorb incident optical light and transfer the energy to oxygen molecules in close proximity, generating cytotoxic singlet oxygens. First, the zebrafish embryos were soaked in the SiQDNP suspension in E3 medium, while being illuminated under blue light or kept in the dark for 6 h. Through neutral red staining immediately afterward, the illuminated embryos showed more prominent injuries at their head, yolk sac and tail parts than those in the dark. Furthermore, prolonged observation after the treatment revealed that the illuminated embryos had mortality rates significantly higher than those without illumination, clearly showing the phototoxicity effect generated by the SiQDNPs. However, adverse effect due to the immersion of whole embryos in the SiQDNP suspension was also observed. To alleviate this issue, minute amounts of the SiQDNPs were microinjected to the embryos, followed by blue light illumination. By acridine orange staining subsequently, cell apoptosis localized near the microinjection site was revealed, whereas no apoptosis was found for those also microinjected with the SiQDNPs but without illumination. The phototoxicity effect demonstrated on zebrafish embryos in this work manifests the potential of using the SiQDNPs as a photosensitizer for photodynamic therapy.

Influence of Contacting Schemes on Electromagnetic Force and Current Density Distribution in Armature

The current density and electromagnetic force distribution of the armature directly affect the performance of electromagnetic railgun. In this paper, the electromagnetic thrust, electromagnetic pressure, and current density of the C-shaped armature and H-shaped armature are calculated, respectively, by the finite-element method under different Armature–rail contact modes (different contact areas and positions), and the calculation results under different contact modes are compared. The calculation results show that the maximum current density of the armature head is independent of the contact mode, and the position of the maximum current density of the armature tail moves with the advance of the contact position. The separation of the rear part of the armature tail and rail will result in a sharp decrease in electromagnetic pressure, so the armature tail and rail need to maintain contact to ensure a stable current transfer. At the same time, only the head and the rear part of the armature tail are in contact with the rail, the electrical performance of the armature in complete contact with the rail can be achieved. Therefore, the armature adopts the structural design scheme of interference at both ends, which is more conducive to electromagnetic emission and greatly reduces the difficulty of the armature structural design.

HVEM signaling in pulmonary epithelial cells is required for protection against Streptococcus pneumoniae

Abstract The most common cause of community-acquired pneumonia in the world is Streptococcus pneumoniae (S. pneumoniae). It is a serious and urgent issue to develop new therapies including non-antibiotic treatments for this pathogen. The herpes virus entry mediator (HVEM), a member of the tumor necrosis receptor super family 14 (TNFRSF14), has been reported to provide host innate immune defense in intestinal mucosal barriers against Citrobacter rodentium infection. Here we show using C10-Cre transgenic mice crossed to mice with a floxed Hvemallele that mice with pulmonary bronchiolar non-ciliated Clara cell-specific deletion of HVEM (HvemdelCC10) display higher bacterial burden and increased mortality after S. pneumoniae infection. Injection of an HVEM neutralizing antibody had a similar effect. This indicates that epithelial HVEM is also critical for pulmonary mucosal protection during the infection. In response to S. pneumonia, HVEM-deficiency led to reduced CXCL1 secretion, accompanied by impaired neutrophil recruitment to the lung. Likewise, deletion of part of the cytoplasmic tail of HVEM (HvemdelCT), causing loss of the ability of HVEM to signal, showed a similar susceptibility to S. pneumonia, indicating the importance of the intracellular signaling of HVEM in epithelial cells for the bacterial clearance. Taken together, these results reveal the protective role of HVEM in epithelial cells against S. pneumonia infection and suggest that activated HVEM signaling in epithelial cells could be used for the treatment of S. pneumoniae infection.

Precise control of nanoscale spacing between electrodes using different natured self-assembled monolayers

Herein, we introduce an interdigitated horizontal electrode (IHE) structure with a metal-based electron-collecting (or -injecting) electrode and a hole-collecting (or -injecting) electrode composed of a conductive polymeric material that has a nanoscale distance and is horizontally separated. In the IHE, a metal electrode is fabricated on a silicon-oxide substrate, and a self-assembled monolayer (SAM) is selectively bonded to the metal and the oxide to form a conductive polymer electrode by dip coating. Each of the SAM materials is composed of a head part bonded to the substrate surface and a tail part that is hydrophilic or hydrophobic. This inherent property makes the metal electrode hydrophobic and the oxide substrate hydrophilic. Ag is used as a metal electrode material and is combined with alkanethiol SAMs. The alkylsilane SAMs are combined with the silicon oxide substrate to make them hydrophilic, using poly (3, 4-ethylenedioxythiophene)-poly (PEDOT: PSS) as the conductive polymer material. In this study, we have found that there is a difference in the spacing between the two electrodes that depends on the combination of SAM materials. Each interval was spaced from a minimum of 140 nm to a maximum of 385 nm.

Design and synthesis of novel PARP-1 inhibitors based on pyridopyridazinone scaffold

Various pyridopyridazinone derivatives were designed as Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors. The pyridopyridazinone scaffold was used as an isostere of the phthalazine nucleus of the lead compound Olaparib in addition to some modifications in the tail part of the molecule. Preliminary biological evaluation indicated that most compounds possessed inhibitory potencies comparable to Olaparib in nanomolar level. The best PARP-1 inhibitory activity was observed for compound 8a with (IC50 = 36 nM) compared to Olaparib as a reference drug (IC50 = 34 nM). Molecular modeling simulation revealed that, the designed compounds docked well into PARP-1 active site and their complexes are stabilized by three key hydrogen bond interactions with both Gly863 and Ser904 as well as other favorable π-π and hydrogen-π stacking interactions with Tyr907 and Tyr896, respectively. Computational ADME study predicted that the target compounds 8a and 8e have proper pharmacokinetic and drug-likeness properties. These outcomes afford a new structural framework for the design of novel inhibitors for PARP-1.

Adhesion Control of Elastomer Sheet on the Basis of Interfacial Segregation of Hyperbranched Polymer.

Adhesion of a model rubbery material, cross-linked poly(dimethylsiloxane) (PDMS), onto a solid surface was studied by sum-frequency generation spectroscopy and X-ray photoelectron spectroscopy. To do so, here, we have focused on the adhesive deposit and insoluble layer. The former and latter were defined as the residual amount on the substrate after the peeling and residual layer after washing with a good solvent, respectively. The peel strength of a PDMS sheet adhered onto a glass plate increased with the contact time. Both adhesive deposit and insoluble layer also exhibited comparable contact time dependence. Once a hyperbranched polymer (HBP), which was segregated to the adhesive interface, was incorporated into PDMS, the peel strength and adhesive deposit decreased, although the thickness of the insoluble layer remained almost unchanged. These results suggest that the formation of loosely adsorbed chains on the solid surface, which possess not only trains but also many loop portions and tail parts, plays an important role in the macroscopic adhesion behavior of the PDMS sheet and the interfacial segregation of HBP can prevent it.

Phenotypic Characterization of Indonesian Native Chicken with Different Combs

The study was conducted to characterize the phenotypic appearance of Indonesian native chickens with difference combs. A total forty chickens were divided onto four groups based on comb type: single, pea, rose and walnut. Qualitative data were tabulated onto head, body and tail parts, and analysed statisticaly using desciptive statistics. As a results, beak color of chicken was vary from dark yellow, light yellow, pale yelow and white. The dark yellow of beak was dominated by chicken with single comb (40%). Light yellow mostly found in chicken with rose comb and, walnut have dominantly pale yellow (50%). Only Chicken with single and pea have white beak color in a few percentage (10%). All comb types of chicken have dark eye color. Chicken with single, pea and walnut combs dominantly have red brown crown color 50%, 40% and 80%, respectively. Chickens with rose comb were most found havnig red crown color (50%). Similary in neck feather color was dominated by single, pea and walnut. Chickens with rose comb indicated yellow (50%) and red crown (40%) color. For chest feather color, chicken with single and walnut comb were dominanted black color (50% and 40%, respectively). The pea and rose comb of chicken mostly have whitebrown (40%) and red (40%) color of chest feather. For abdomen feather color, chicken with single (50%), pea (40%) and walnut (40%) were mostly have black color, but chicken with rose comb indicated mostly red (40%). Similary in back feather color, balck feather was dominated in single, pea and walnut. Both primer and seconder wing feather color were found black in all comb types. The tail feather color was vary, chicken with single comb was dominantly have black color (40%).Chicken with rose and walnut comb have black-white tail feather, 50% and 60%, respectively. Most of chicken with pea comb have black-green tail feather color. All the comb type dominantly have black thigh color. Inconclusion, this study may provide an important view for designing conservation and breeding strategies to efficiently protect and utilize the existing variation phenotypics among local chicken populations.

Investigation of density and form factor of some F isotopes using Hartree-Fock and shell model calculations

Structure of unstable 21,23,25,26F nuclei have been investigatedusing Hartree – Fock (HF) and shell model calculations. The groundstate proton, neutron and matter density distributions, root meansquare (rms) radii and neutron skin thickness of these isotopes arestudied. Shell model calculations are performed using SDBAinteraction. In HF method the selected effective nuclear interactions,namely the Skyrme parameterizations SLy4, Skeσ, SkBsk9 andSkxs25 are used. Also, the elastic electron scattering form factors ofthese isotopes are studied. The calculated form factors in HFcalculations show many diffraction minima in contrary to shellmodel, which predicts less diffraction minima. The long tailbehaviour in nuclear density is noticeable seen in HF more than shellmodel calculations. The deviation occurs between shell model andHF results are attributed to the sensitivity of charge form factors tothe change of the tail part of the charge density. Calculations donefor the rms radii in shell model showed excellent agreement withexperimental values, while HF results showed an overestimation inthe calculated rms radii for 21,23F and good agreement for 25,26F. Ingeneral, it is found that the shell model and HF results have the samebehaviour when the mass number (A) increase.

Charge density distributions and electron scattering form factors of 25Mg, 27Al and 29Si nuclei

An effective two-body density operator for point nucleon systemfolded with the tenser force correlations( TC's), is produced and usedto derive an explicit form for ground state two-body charge densitydistributions (2BCDD's) applicable for 25Mg, 27Al and 29Si nuclei. It isfound that the inclusion of the two-body TC's has the feature ofincreasing the central part of the 2BCDD's significantly and reducingthe tail part of them slightly, i.e. it tends to increase the probability oftransferring the protons from the surface of the nucleus towards itscenteral region and consequently makes the nucleus to be more rigidthan the case when there is no TC's and also leads to decrease the1/ 2r 2 of the nucleus. It is also found that the effect of the TC's and theeffect of increasing the values of  on the 2BCDD's, elasticelectron scattering form factors and r2 1/ 2 are in the same directionfor all considered nuclei.

Structural signatures of the class III lasso peptide BI-32169 and the branched-cyclic topoisomers using trapped ion mobility spectrometry-mass spectrometry and tandem mass spectrometry.

Lasso peptides are a class of bioactive ribosomally synthesized and post-translationally modified peptides (RiPPs) characterized by a mechanically interlocked topology, where the C-terminal tail of the peptide is threaded and trapped within an N-terminal macrolactam ring. BI-32169 is a class III lasso peptide containing one disulfide bond that further stabilizes the lasso structure. In contrast to its branched-cyclic analog, BI-32169 has higher stability and is known to exert a potent inhibitory activity against the human glucagon receptor. In the present work, tandem mass spectrometry, using collision-induced dissociation (CID) and electron capture dissociation (ECD), and trapped ion mobility spectrometry-mass spectrometry (TIMS-MS) experiments were carried out to evidence specific structural signatures of the two topologies. CID experiments showed similar fragmentation patterns for the two topoisomers, where a part of the C-terminal tail remains covalently linked to the macrolactam ring by the disulfide bond, which cannot clearly constitute a signature of the lasso topology. ECD experiments of BI-32169 showed an increase of hydrogen migration events in the loop region when compared with those of its branched-cyclic topoisomer evidencing specific structural signatures for the lasso topology. The high mobility resolving power of TIMS resulted in the identification of multiple conformations for the protonated species but did not allow the clear differentiation of the two topologies in mixture. When in complex with cesium metal ions, a reduced number of conformations led to a clear identification of the two structures. Experiments reducing and alkylating the disulfide bond of BI-32169 showed that the lasso structure is preserved and heat stable and the associated conformational changes provide new insights about the role of the disulfide bond in the inhibitory activity against the human glucagon receptor. Graphical abstract ᅟ.

Influence of operating conditions on the accuracy of the automated system for measuring geometric parameters of graphical methods and measuring deviations of technological channels from the vertical of channel reactors

During operation of the reactor, along its active zone, the energy release is unevenly distributed, consequently also the temperature. These operational parameters introduce an error in the measurement of the system. Of practical interest is the study of the temperature stability of ultrasound sensors, as well as the effect of vibration on the oscillations of the ultrasonic signal. The system solves the problem of controlling the curvature and the diameter of the cells of the graphite masonry of the EGP-6 reactors in two mutually perpendicular planes during the routine preventive and overhaul repairs. Diameter control is carried out by means of 4 sensors of displacement of the resistor type fixed on the sensor probe block. Each of the sensors is mechanically connected to the roller, which is in direct contact with the channel wall. Diameter measurement uses data from sensors connected to two opposite rollers. Curvature control is performed using an ultrasonic inclinometer filled with liquid, which is located in the tail part of the probe. The inclinometer is designed for measuring angles of inclination in 2 mutually perpendicular planes. The data from the inclinometer is transmitted via the interface to an analog-to-digital converter, which is located in the measuring unit and is designed to convert the interface to USB.

JmjC Domain-Encoding Genes Are Conserved in Highly Regenerative Metazoans and Are Associated with Planarian Whole-Body Regeneration.

The capacity for regeneration varies greatly among metazoans, yet little is known about the evolutionary processes leading to such different regeneration abilities. In particular, highly regenerative species such as planarians and cnidarians can regenerate the whole body from an amputated fragment; however, a common molecular basis, if any, among these species remains unclear. Here, we show that genes encoding Jumonji C (JmjC) domain-containing proteins are associated with high regeneration ability. We classified 132 fully sequenced metazoans into two groups with high or low regeneration abilities and identified 118 genes conserved in the high regenerative group that were lost in species in the low regeneration group during evolution. Ninety-six percent of them were JmjC domain-encoding genes. We denoted the candidate genes as high regenerative species-specific JmjC domain-encoding genes (HRJDs). We observed losses of HRJDs in Helobdella robusta, which lost its high regeneration ability during evolution based on phylogenetic analysis. By RNA sequencing analyses, we observed that HRJD orthologs were differentially expressed during regeneration in two Cnidarians, as well as Platyhelminthes and Urochordata, which are highly regenerative species. Furthermore, >50% of the head and tail parts of amputated planarians (Dugesia japonica) died during regeneration after RNA interference of HRJD orthologs. These results indicate that HRJD are strongly associated with a high regeneration ability in metazoans. HRJD paralogs regulate gene expression by histone demethylation; thus, HRJD may be related to epigenetic regulation controlling stem cell renewal and stem cell differentiation during regeneration. We propose that HRJD play a central role in epigenetic regulation during regeneration.