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The outbreak of infectious diseases often exhibits periodicity, and this periodic behavior can be mathematically represented as a limit cycle. However, the periodic behavior has rarely been considered in demonstrating the cluster phenomenon of infection induced by diffusion (the instability modes) in the SIR model. We investigate the emergence of Turing instability from a stable equilibrium and a limit cycle to illustrate the dynamical and biological mechanisms of pattern formation. We identify the Hopf bifurcation to demonstrate the existence of a stable limit cycle using First Lyapunov coefficient in our spatiotemporal diffusion-driven SIR model. The competition between different instability modes induces different types of patterns and eventually spot patterns emerge as stable patterns. We investigate the impact of susceptible, infected, and recovered individuals on the type of patterns. Interestingly, these instability modes play a vital role in selecting the pattern formations, which is directly related to the number of observed spot patterns. Subsequently, we explain the dynamical and biological mechanisms of spot patterns to develop an effective epidemic prevention strategy. [ABSTRACT FROM AUTHOR]

Merocyanine dyes are of great interest amongst researchers due to their nonlinear optical (NLO) properties and solvatochromism. Molecular structure of these dyes constitutes conjugated pathway between the donor and acceptor substituents, with lowest energy transition of π – π * character. To rationalize the design of these dyes and deduce structure-property relationship, it is eminent to unravel the excited state dynamics in these complex molecular structures in different solvents. Here we have studied excited state dynamics of a merocyanine dye known as HB194, which has shown commendable efficiency in small molecule based bulk heterojuction solar cells. We have employed femtosecond transient absorption in combination with the quantum chemistry calculations to unravel the solvent dependent charge transfer dynamics of HB194. The excited state decays of the HB194 in different solvents show multi-exponential components. The analysis of the time-resolved data reveals that the polar solvents induce conformationally relaxed intramolecular charge transfer state. In non-polar solvent cyclohexane, only solvent-stabilized ICT state is observed. Additionally, we observe an anomalously red-shifted emission in ethylene glycol centred at ∼ 750 nm. Our computational calculations suggest the presence of molecular dimers resulting into observed red-shifted emission band. Our work therefore underscores the importance of gathering molecular-level insight into the system-bath interactions for designing next generation merocynanine-based solvatochromic dyes. [ABSTRACT FROM AUTHOR]

Higher-order networks reveal intricate structural connections within neural brain models by exposing relationships between multiple nodes. Within human brain networks, information transmission among neurons invariably incurs a time delay, resulting in abnormal discharge of membrane potential. In this study, we analyze correlation visualizations of the Laplacian matrix derived from both general networks and higher-order networks, highlighting eigenvector distributions. The presence of time delay significantly influences the dynamical behavior of the system. Therefore, we examine the phase diagram, identifying firing patterns such as fast-spiking and mixed-mode oscillations. Ultimately, we demonstrate that both time delay and diffusion can alter the dynamical behavior of the FitzHugh–Nagumo model. Notably, within higher-order networks, the phenomenon of Turing instability becomes more pronounced, offering an analogous framework for studying associated diseases. This instability emerges as neuronal states approach abnormal levels, leading to the onset of related diseases. Numerical simulation and data also verify these results. [ABSTRACT FROM AUTHOR]

Turing instability is a prominent feature of reaction–diffusion systems, which is widely investigated in many fields, such as ecology, neurobiology, chemistry. However, although the inhomogeneous diffusion between prey and predators exist in their network space, there are few considerations on how network diffusion affects the stability of prey–predator models. Therefore, in this paper we study the pattern dynamics of a modified reaction–diffusion Holling–Tanner prey–predator model over a random network. Specifically, we study the relationship between the node degrees of the random network and the eigenvalues of the network Laplacian matrix. Then, we obtain conditions under which the network system instability, Hopf bifurcation as well as Turing bifurcation occur. Also, we find an approximate Turing instability region of the diffusion coefficient and the connection probability of the network. Finally, we apply the mean-field approximation theory with numerical simulation to confirm the correctness of our results. The instability region indicates the random migration of the prey and predators among different communities. [ABSTRACT FROM AUTHOR]

In this paper, we show some dynamical and biological mechanisms of the short-term memory (the fixed point attractor) through the toggle switch in the FitzHugh-Nagumo model (FN). Firstly, we obtain the bistable conditions, show the effect of Gaussian noise on the toggle switch, and explain the short-term memory's switch mechanism by mean first passage time (MFPT). Then, we obtain a Fokker-Planck equation and illustrate the meaning of the monostable and bistable state in the short-term memory. Furthermore, we study the toggle switch under the interaction of network and noise. Meanwhile, we show that network structure and noise play a vital role in the toggle switch based on network mean first passage time (NMFPT). And we illustrate that the modest clustering coefficient and noise are necessary to maintain memories. Finally, the numerical simulation shows that the analytical results agree with it. [ABSTRACT FROM AUTHOR]

P53 plays a vital role in DNA repair, and several mathematical models of the p53-Mdm2 feedback loop were used to explain the biological mechanism. In this paper, a p53-Mdm2 model described by a delay reaction–diffusion equation is studied both analytically and numerically. This research aims to provide an understanding of the impact of delay and sustained pressure on the p53-Mdm2 dynamics and tries to explain some biological mechanism. It is found that the type of pattern formation is affected by Hopf bifurcation. Also, the amplitude equation in delay diffusive system is derived and it is shown that sustained stress plays an essential role in the function of p53. Finally, simulation is used to verify the theoretical results. [ABSTRACT FROM AUTHOR]

We established a two‐dimensional strong cation exchange/reversed‐phase liquid chromatography protocol to isolate and purify isoquinoline alkaloids from Corydalis impatiens. Isoquinoline alkaloids were first enriched from a C. impatiens extract in which liposoluble components were removed using a medium‐pressure chromatographic tower containing middle chromatogram isolated gel. A strong cation exchange column was employed to separate and obtain 30 fractions. We chose fractions 22–29 for reversed‐phase liquid chromatography purification using characteristic isoquinoline alkaloid ultraviolet absorption spectra. Several isoquinoline alkaloid fractions (22–29) were further separated, and those of low resolution were isolated via two‐dimensional liquid chromatography in the orthogonal plane. A total of eight novel isoquinoline alkaloids with characteristic ultraviolet spectra were obtained from C. impatiens. We thus demonstrate the benefits of off‐line two‐dimensional strong cation exchange/reversed‐phase liquid chromatography to isolate isoquinoline alkaloids from C. impatiens. [ABSTRACT FROM AUTHOR]

The spread of infectious diseases often presents the emergent properties, which leads to more difficulties in prevention and treatment. In this paper, the SIR model with both delay and network is investigated to show the emergent properties of the infectious diseases' spread. The stability of the SIR model with a delay and two delay is analyzed to illustrate the effect of delay on the periodic outbreak of the epidemic. Then the stability conditions of Hopf bifurcation are derived by using central manifold to obtain the direction of bifurcation, which is vital for the generation of emergent behavior. Also, numerical simulation shows that the connection probability can affect the types of the spatio-temporal patterns, further induces the emergent properties. Finally, the emergent properties of COVID-19 are explained by the above results. [ABSTRACT FROM AUTHOR]

• Two novel pharmaceutical salts of letermovir (LM) were successfully achieved. • This is the first report of a single crystal structure of LM, which could contribute to the development of corresponding drugs. • Salt 1 and salt 2 showed better solubility and stability under wet conditions, and had the potential to replace the bulk drug. Two novel pharmaceutical salts of letermovir (LM) were successfully achieved by a slow reaction in solution containing LM with ethylenediamine (EDA) and diisopropylamine (DIPA). In this article, crystal structure, X-ray diffraction, thermal properties, 1H NMR, 13C NMR, HPLC analysis, stability and solubility of salt 1 and salt 2 have been discussed. Salt 1 crystalized in R 3 space group and salt 2 crystalized in P 3 2 21 space group. The formation of salt was proved by p K a rule and single crystal determination. From the perspective of crystal structure, for salt 1 and salt 2 , the strong hydrogen bond makes the crystal structure more stable. The weak interaction between molecules is further studied by Hirshfeld surface and 2D-fingerprint plots. Notably, this is the first report of a single crystal structure of LM, which could contribute to the development of corresponding drugs. In addition, salt 1 and salt 2 showed better solubility and stability under wet conditions, and had the potential to replace the bulk drug. Two novel pharmaceutical salts of letermovir (LM) were successfully synthesized. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, a predator–prey system with double Allee effects and time delay is considered. On the one hand, by using time delay as bifurcation parameter, the stability of the interior equilibrium point is studied. It is shown that under certain assumptions the equilibrium point of the delay model is locally asymptotically stable for all delay values, otherwise, there is a critical value, such that the equilibrium point is locally stable when time delay is less than the critical value, and Hopf bifurcation occurs when the delay crosses the critical value. Numerical simulations are carried out to validate the analytical results. On the other hand, we investigate the following four submodels respectively: the time-delayed system without Allee effect, the time-delayed system with Allee effect on predator, the time-delayed system with Allee effect on prey and the time-delayed system with double Allee effects. Compared with the situation without Allee effects, Allee effect on predator causes a decline of the equilibrium state of the predator, the equilibrium state of the prey and critical time delay are almost unaltered; Allee effect on prey and Allee effect on prey and predator all lead to the descent of the equilibrium state of the predator and prey, inversely, and critical time delay has an obvious rise. A comparison of the four cases indicates that Allee effect can alter the magnitudes of predator density and prey density at future time, the time that predator and prey cost to keeping steady state is also changed. [ABSTRACT FROM AUTHOR]

Somitogenesis, the sequential formation of a periodic pattern along the anteroposterior axis of vertebrate embryos, is one of the most obvious examples of the segmental patterning processes that take place during embryogenesis and also one of the major unresolved events in developmental biology. In this paper, we investigate the effect of diffusion on pattern formation use a modified two dimensional model which can be used to explain somitogenesis during embryonic development. This model is suitable for exploring a design space of somitogenesis and can explain many aspects of somitogenesis that previous models cannot. In the present paper, by analyzing the local linear stability of the equation, we acquired the conditions of Hopf bifurcation and Turing bifurcation. In addition, the amplitude equation near the Turing bifurcation point is obtained by using the methods of multi-scale expansion and symmetry analysis. By analyzing the stability of the amplitude equation, we know that there are various complex phenomena, including Spot pattern, mixture of spot–stripe patterns and labyrinthine. Finally, numerical simulation are given to verify the correctness of our theoretical results. Somitogenesis occupies an important position in the process of biological development, and as a pattern process can be used to investigate many aspects of embryogenesis. Therefore, our study helps greatly to cell differentiation, gene expression and embryonic development. What is more, it is of great significance for the diagnosis and treatment of human diseases to study the related knowledge of model biology. [ABSTRACT FROM AUTHOR]

Abstract: There is a great challenge to overcome the limitation of tissue penetration depth, while maximizing the benefit of light‐triggered biochemical cascades in a well‐defined mode simultaneously. Here, a new method of near‐infrared (NIR) light‐triggered release of nitric oxide (NO) by developing upconversion nanoparticles (UCNPs)‐based conjugate chemistry is reported. As the key nanotransducer in the design, core–shell‐structured UCNPs are encapsulated with a layer of SiO2 and then covalently linked with a potent NO‐releasing donor (S‐nitroso‐N‐acetyl‐ dl‐penicillamine, SNAP). It is featured with highly localized breakage of chemical bonds of SNAP molecules by NIR–UV upconversion, enabling simultaneous NO release in a light dosage‐dependent manner. The biological effects of NO releasing are demonstrated by cellular imaging and inhibition of platelet aggregation from blood samples. This work provides a flexible and robust platform to generate cell‐signaling gas molecules trigged by NIR laser with deep tissue penetration. [ABSTRACT FROM AUTHOR]

In this paper, we will investigate the effect of diffusion, which is ubiquitous in nature, on the immune system using a reaction-diffusion model in order to understand the dynamical behavior of complex patterns and control the dynamics of different patterns. Through control theory and linear stability analysis of local equilibrium, we obtain the optimal condition under which the system loses stability and a Turing pattern occurs. By combining mathematical analysis and numerical simulation, we show the possible patterns and how these patterns evolve. In addition, we establish a bridge between the complex patterns and the biological mechanism using the results from a previous study in Nature Cell Biology. The results in this paper can help us better understand the biological significance of the immune system. [ABSTRACT FROM AUTHOR]

The diffusion of the susceptible and infected is a vital factor in spreading infectious diseases. However, the previous SIR networks cannot explain the dynamical mechanism of periodic behavior and endemic diseases. Here, we incorporate the diffusion and network effect into the SIR model and describes the mechanism of periodic behavior and endemic diseases through wavenumber and saddle–node bifurcation. We also introduce the standard network structured entropy (NSE) and demonstrate diffusion effect could induce the saddle–node bifurcation and Turing instability. Then we reveal the mechanism of the periodic outbreak and endemic diseases by the mean-field method. We provide the Turing instability condition through wavenumber in this network-organized SIR model. In the end, the data from COVID-19 authenticated the theoretical results. • SIR model with an ER network is constructed to show the effects of the network on Turing instability. • the network structured entropy (NSE) and diffusion could induce the bifurcation and Turing instability. • Mechanism of the periodic outbreak and endemic diseases is revealed. • Turing instability condition was given and verified through wavenumber. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the effect of diffusion on pattern formation in FitzHugh–Nagumo model. Through the linear stability analysis of local equilibrium we obtain the condition how the Turing bifurcation, Hopf bifurcation and the oscillatory instability boundaries arise. By using the method of the weak nonlinear multiple scales analysis and Taylor series expansion, we derive the amplitude equations of the stationary patterns. The analysis of amplitude equations shows the occurrence of different complex phenomena, including Turing instability Eckhaus instability and zigzag instability. In addition, we apply this analysis to FitzHugh–Nagumo model and find that this model has very rich dynamical behaviors, such as spotted, stripe and hexagon patterns. Finally, the numerical simulation shows that the analytical results agree with numerical simulation. [ABSTRACT FROM AUTHOR]

We demonstrate a simple method for the determination of the magnetic field in an ion trap using laser-cooled Be ions. The method is not based on magnetic resonance and thus does not require delivering radiofrequency (RF) radiation to the trap. Instead, stimulated Raman spectroscopy is used, and only an easily generated optical sideband of the laser cooling wave is required. The d.c. magnetic vector, averaged over the Be ion ensemble, is determined. Furthermore, the field strength can be minimized and an upper limit for the field gradient can be determined. The resolution of the method is 0.04 G at present. The relevance for precision rovibrational spectroscopy of molecular hydrogen ions is briefly discussed. [ABSTRACT FROM AUTHOR]

Black band disease (BBD), characterized by the Cyanobacterial dominated pathogenic consortium, is thought to play a key role in the global decline of the coral reef ecosystems. The present paper originally documents a case of BBD from Yongxing Island (Xisha Islands, South China Sea), and further probes the reasons of this abnormal phenomenon. Prior to 2007, corals at northern reef-flat of Yongxing Isand were in healthy growth. Catastrophic coral mortality occurred between 2007 and 2008. The 16S rRNA gene sequencing and PCR amplification, with universally conserved primers, were applied to detect the contagious bacterial community of the microbial mat. The results demonstrated that six bacterial divisions constituted the clone libraries derived from the BBD mat, and that Cyanobacteria are the most diversely represented group that inhabit BBD bacterial mats, despite the fact that species in five others divisions (α-Proteobacteria, γ-Proteobacteria, Bacteroidetes, Verrucomicrobia and Actinobacteria) are also consistently diverse within the BBD mats of diseased coral. Other factors such as coral bleaching, typhoons, ocean acidification and crown-of-thorns starfish outbreaks, are not primarily responsible for the coral mortality within such a short time interval. The disaster expansion of BBD associated with Cyanobacterial blooms is a more likely mechanism impacting these coral reefs. Excessive human activity enhances the eutrophication of the marine water of the reefal region and may result in occurrence of the BBD. [ABSTRACT FROM AUTHOR]

Microbes and microbial carbonates in reef-flat and coral community dynamics and submarine geomorphologic features in reef crest and fore reef of Yongxing Island, the Xisha Islands, South China Sea, were studied by means of scuba diving, underwater investigation, and line intercept transect survey. Studies indicate a very high coral mortality with few living corals in the reef flat of Yongxing Island. Moreover, macro algae, sea grass and cyanobacteria are common in reef flat. Microbes and microbially induced carbonates occur in reef flat. Living corals grow mainly in the reef crest and fore reef, but are also declined dramatically. From coast to off shore, the southeast reef flat of Yongxing Island can be divided into beach, inner reef flat, outer reef flat, reef flat front (reef crest and fore reef), and fore-reef slope settings. Sedimentary facies include coast, reef flat, reef crest and fore reef, and fore-reef slope. Reefal carbonate sediments are composed of coral skeletons and framework, coral fragments, bioclasts, and lime mud. With the deterioration of environment and water quality, the coral communities tend to be distributed in the reef crest and fore reef with clean sea water, well circulation and moderate water energy. Reef flat is occupied mainly by the macro algae and Heliopora coerulea communities. The coverage statistics on the reef crest demonstrate that the coverage of Acropora cytherea is more than 28% and represents a dominant species with wave-resistant ecological type. Sedimentary characteristics and geomorphologic features are different between the southeast and northwest reef-flat fronts (reef crest and fore reef) of Yongxing Island. The former shows discontinuously tidal channels in outer reef flat and different dimensional and deep reef ponds in reef crest and fore reef, and the latter presents a typical spur-and-groove system. Microbes (cyanobacteria Lyngbya sp.) occur generally in the inner reef flat and reef ponds of reef crest with restricted water circulation. Widely algae growth indicates a eutrophic environment, and the common microbes on the coral surface in the reef flat and reef ponds also demonstrate eutrophication in seawater and deteriorated water quality. [ABSTRACT FROM AUTHOR]

Polychaete serpulids are globally distributed tubeworms mostly in marine environments from Late Triassic to modern time. These calcareous tubeworms could be rock-forming, reef-building, or a principal fouling organism in harbor and bays. Carbonates of the Paleogene Kalatar Formation in southwest Tarim Basin yield abundant serpulid fossils, which, together with oyster fossils, constitute the characteristic fossil assemblage of the Kalatar Formation. Other common fossils include bivalves, gastropods, ostracods, echinoderms, and bryozoans. Lithologies that yielded serpulid fossils are characterized by micritic bioclastic limestone, sandy limestone, and shelly limestone, indicating a semi-restricted to open shallow marine environment with medium to low water energy. The research data about serpulids and their fossil materials from China are relatively rare. Based on the studies of fossils taxonomy, community palaeoecology, and fossil taphonomy, this paper analyzed and studied the types, occurrence, distribution, and morphological characteristics of serpulids and their palaeoecological features in the Kalatar Formation. Two serpulid community compositions were recognized in the Kalatar Formation, including a rock-forming Ditrupa community and a cluster-growth Propomatoceros community. The Ditrupa community was distributed in coastal environment of the west Kunlun piedmont, lived on sandy hard substrates with little mud, and rarely occurred in lagoon and tidal settings. The Propomatoceros community occurred in offshore middle carbonate ramp in the piedmont of the south Tianshan Mountains and in offshore shelf in the piedmont of the west Kunlun Mountains. According to the analysis on the host-rock lithologies, preservation and symbionts, it is inferred that serpulids in the Kalatar Formation grew on the oyster shell or other hard substrate, and they did not form reefs or bioherms. [ABSTRACT FROM AUTHOR]

Modern fringing reefs are developed on the intertidal to subtidal area of Xiaodonghai bay, Sanya, Hainan Island. The reef flat extends several dozen meters toward the sea. Various ecological and sedimentary zonations can be distinguished, including, from land to sea, beachrocks, large massive corals, inner reef flat, outer reef flat, and fore-reef slope. The carbonate sediments and constituent hermatypic coral communities are different in these zones. The beachrocks are composed mainly of biological sands, including coral skeletons, algae, gastropods, bivalves, and benthic foraminifera. Quartz sands are less common in this zone. Carbonate diagenesis in beachrocks is characterized by early cementation. The fringing reef flat is progradationally developed toward the sea. Large massive corals grew in the zone next to the beachrocks. These corals are large, flat-toped, and autochthonous in the production of bioclastic grains and lime mud. Large and massive coral skeletons are surrounded by coral skeletal grains, bioclasts, and lime-mud sediments. The inner reef flat consists mainly of skeletons of branching corals that are covered by bioclasts and lime mud, and living corals are mostly massive in form. Statistical analysis of coral-community dynamics shows that the outer reef flat with strong waves is the most suitable place for hermatypic corals to flourish. There, the living corals are most densely distributed. Both massive corals and branching corals (e.g., Acropora corymbosa) are exceptionally healthy in this zone. Bioclasts and lime mud are washed out due to strong wave action. Microbial carbonates generally are deposited within cavities of the beachrocks and coral skeletal cavities and on the surfaces of bioclastic grains. The latter two types, however, are more common. Ecological-sedimentary zonations across the Xiaodonghai reef flat from beachrocks to outer reef flat are controlled by variations in wave strength and water energy. Microbial carbonates rarely developed on outer reef flat under strong wave action. [ABSTRACT FROM AUTHOR]

Late Frasnian mounds of the Yunghsien Formation, Guilin, South China, developed as part of the Guilin platform, mostly in reef-flat and platform margin settings. Microbial mounds in platform margin settings at Hantang, about 10 km west of Guilin, contain Frasnian biota, such as Stachyodes and Kuangxiastraea and, thus, occur below the Frasnian-Famennian mass extinction boundary. Platform margin facies were dominated by microbes, algae and receptaculitids. Massive corals and stromatoporoids are not common and rarely show reef-building functions as they did in Givetian time. The margin mounds are composed of brachiopod-receptaculitid cementstone, and a variety of boundstones that contain Rothpletzella, Renalcis, thrombolite and stromatolite. Other microbial communities include Girvanella, Izhella, Ortonella and Wetheredella. Solenoporoid algae are abundant locally. Zebra structures and neptunian dykes are well-developed at some intervals. Pervasive early cementation played an important role in lithification of the microbial boundstones and rudstones. Frasnian reefs of many regions of the world were constructed by stromatoporoids and corals, although a shift to calcimicrobe-dominated frameworks occurred before the Famennian. However, the exact ages of many Frasnian margin outcrops are poorly constrained owing to difficulties dating shallow carbonate facies. The Hantang mounds represent a microbe-dominated reef-building community with rare skeletal reef builders, consistent with major Late Devonian changes in reef composition, diversity and guild structure occurring before the end of the Frasnian. A similar transition occurred in the Canning Basin of Western Australia, but coeval successions in North America, Western Europe and the northern Urals are either less well-known or represent different bathymetric settings. The transition in reef-building style below the Frasnian-Famennian boundary is documented here in the two best exposed successions on two continents, which may have been global. Set in the larger context of Late Devonian and Mississippian microbial reef-building, the Hantang mounds help to demonstrate that controls on microbial reef communities differed from those on larger skeletal reef biota. Calcimicrobes replaced stromatoporoids as major reef builders before the Frasnian-Famennian extinction event, and increasing stromatoporoid diversity towards the end of the Famennian did not result in a resurgence of skeletal reef frameworks. Calcimicrobes dominated margin facies through the Famennian, but declined near the Devonian-Carboniferous boundary. Stromatolite and thrombolite facies, which occurred behind the mound margin at Hantang, rose to dominate Mississippian shallow-water reef frameworks with only a minor resurgence of the important Frasnian calcimicrobe Renalcis in the Visean when well-skeletonized organisms (corals) also became volumetrically significant frame builders again. [ABSTRACT FROM AUTHOR]

Abstract: By using the bifurcation theory of dynamical systems to modified nonlinear dispersive phi-four equation, we analysis all bifurcations and phase portraits in the parametric space, the existence of solitary wave solutions and uncountably infinite many smooth and non-smooth periodic wave solutions is obtained. Under different parametric conditions, various sufficient conditions to guarantee the existence of the above solutions are given. Some explicit exact solution formulas are acquired for some special cases. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we investigate the problem how to establish the robust stability of uncertain gene networks with time-varying delays and noise. Specifically, we consider uncertain gene networks where the regulation occurs at the mRNAs level, and we obtain a sufficient condition for robust stability by Lyapunov method and inequality technique. Moreover, we show that these condition can be formulated as linear matrix inequalities (LMIs), which are easy to be verified by the convex optimization. Finally, two of the most common motifs are investigated to illustrate the effectiveness and the correctness of our results. [Copyright &y& Elsevier]

Abstract: More and more experiments show that small RNAs regulate gene expression by repressing translation of messenger RNAs (mRNAs) or degrading mRNAs. In this paper, we incorporate the small RNAs into a simple gene regulatory network and investigate its dynamical behaviors. In addition, we also derive the theoretical results of globally asymptotic stability and provide the sufficient conditions for the oscillation of the simple gene regulatory network, and further demonstrate that the amplitudes against the change of delay in the gene regulatory network are robust. [Copyright &y& Elsevier]

Abstract: A composite nano-crystalline structured thin film was realized by depositing mixed Al2O3 and MgO coating material using physical vapor deposition approach and then annealing at high temperature. The film thus fabricated retains a high transmission even after annealing at 1500°C. The grain size of less than 100nm was measured by atomic force microscopy and the composite nano-crystalline structure of spinel and corundum was confirmed by the X-ray diffraction pattern analysis. Based on this, Bragg grating stacks were fabricated by depositing alternating quarter-wave layers of Al2O3 and Al2O3/MgO at the end of a sapphire crystal fiber at first and then the layers of NiO and Al2O3/MgO on the surface of a sapphire slice. The performance of the grating stacks at high temperature or after high temperature annealing was measured. It was found that the reflection peak measured from the grating stacks can survive a high temperature up to 1050°C but will disappear after annealing at temperature of 1100°C or above. A conclusion of inter-diffusion between layers of stack was obtained to explain the phenomenon of reflection peak disappearing after annealing at high temperature. [Copyright &y& Elsevier]

Abstract: In this paper, shock wave solutions of the compound Burgers–KdV equation is studied by using qualitative theory of differential equation and ansatz method. The existence and uniqueness of different types of travelling waves of the system are obtained by analyzing qualitatively the existence and uniqueness of the heteroclinic trajectories of the ordinary differential equation. We construct some travelling wave solutions and indicate their stability and bifurcation. [Copyright &y& Elsevier]

Abstract: By using bifurcation method of phase portraits and theory of dynamical systems to the nonlinear Klein–Gordon model, in the range , numbers of kink compactons, solitary wave, kink and anti-kink waves are given for each parameter condition. The parameter condition when the type of travelling wave changes is obtained. [Copyright &y& Elsevier]

Abstract: The dynamical behavior and special exact solutions of the generalized Degasperis–Procesi equation u t + c 0 u x − u txx + auu x =3u x u xx + uu xxx is analyzed by using bifurcation theory and the method of phase portraits analysis. As a result, the analytic expressions of peakon solutions, compacton solutions and periodic cusp wave solutions are obtained. And the condition under which peakon and compacton solutions appear are also given. In the meantime, the reason that solitary cusp wave and periodic cusp wave appear is given. [Copyright &y& Elsevier]

Abstract: By using bifurcation method to Whitham–Broer–Kaup shallow water equations, bifurcation parameter sets are shown. Numbers of solitary waves, kink waves and periodic waves are given. Under various parameter conditions, all explicit formulas of solitary wave solutions, kink wave solutions and periodic wave solutions are listed. [Copyright &y& Elsevier]

Abstract: By using the theory of bifucations of dynamical systems to a model of the Hydrogen-bonded systems, the existence of solitary wave, kink and anti-kink wave solutions and uncountably infinite many smooth and non-smooth periodic wave solutions is obtained. Under different parametric conditions, various sufficient conditions to guarantee the existence of the above solutions are given. In some simple parametric conditions, exact explicit and implicit solution formulas are listed. [Copyright &y& Elsevier]

Abstract: On-target affinity capture, enrichment and purification of biomolecules improve detection of specific analytes from complex biological samples in matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis. In this paper, we report a simple method for preparation of a self-assembled nitrilotriacetic acid (NTA) monolayer on gold surface which can be used as a MALDI-TOF-MS sample target specifically for recombinant oligohistidine-tagged proteins/peptides and phosphorylated peptides. The NTA functional groups are immobilized to the gold surface via the linkage of 1,8-octanedithiol which forms a self-assembled monolayer on gold. Characterization by X-ray photoelectron spectroscopy and MALDI analysis of the modified surface are described. The chemically modified surface shows strong affinity toward the analytes of interest, which allows effective removal of the common interferences, e.g. salts and detergents, and therefore leads to improved signal/noise ratio and detection limit. The use of the modified surface simplifies the sample preparation for MALDI analysis of these targeted analytes. [Copyright &y& Elsevier]

By using the bifurcation theory of dynamical systems to the generalized Hirota–Satsuma coupled KdV system, bifurcation parameter sets are shown. Numbers of solitary waves, kink waves and periodic waves are given. Under various parameter conditions, all explicit formulas of solitary wave solutions and kink wave solutions and periodic wave solutions are listed. [Copyright &y& Elsevier]

A multi-technique approach to identification and mapping of phosphorylation on protein kinase A (PKA) is described. X-ray crystallography revealed phosphorylation at T197 and S338 while mass spectrometry (MS) on the intact protein suggested phosphorylation at three sites. Tryptic digestion, followed by MS, confirmed the presence of three phosphates. However, metal affinity treatment of the digest prior to MS revealed the presence of a fourth phosphopeptide. Subsequent analysis of the digests using liquid chromatography (LC) coupled with quadrupole ion trap (QIT) MS confirmed phosphorylation at S10 and S338 and suggested phosphorylation at S139 and T195/197. Unfortunately, identification of pS139 was inconclusive due to low signal intensity and early elution in reversed-phase LC while poor MS/MS data prevented localization of the phosphate to T195 or T197. Phosphopeptide modification with ethanethiol, followed by LC QIT-MS/MS, identified four phosphopeptides in a single experiment. In addition, the fragmentation data provided significantly more sequence information than data obtained from unmodified peptides. Data from this study suggested that PKA was completely phosphorylated at S10, T197, and S338 and partially phosphorylated at S139. These results illustrate that critical information can be lost unless multiple MS techniques are used for identification and validation of phosphorylation. [Copyright &y& Elsevier]

• The approximate range of eigenvalue of the network matrix is shown. • The instability condition about diffusion and the connection probability in the network-organized system are derived. • The estimated range of connection probability is also deduced. • Mechanism of spiking of the neuron can be explained by using diffusion network and matrix theory. Although there is general agreement that the network plays an essential role in the biological system, how the connection probability of network affects the natural model(Especially neural network) is poorly understood. In this paper, we show the impact of the network on Turing instability in the FitzHugh-Nagumo(FN) model. Then we obtain the condition of how the Turing bifurcation, saddle-node bifurcation, and Turing instability occur. By using the Gershgorin circle theorem, we investigate the relationship between degree and eigenvalue of the network matrix, and obtain the approximate range of eigenvalue of the network matrix. Also, We derive the instability condition about diffusion and the connection probability in the network-organized system. And then we obtain the estimated range of connection probability. Meanwhile we apply these results to explaining the spiking of neuron and find this system has rich dynamics behavior. Finally, the numerical simulation verifies our analytical results. [ABSTRACT FROM AUTHOR]

Evidence suggests that enhancing the osteogenic ability of bone marrow-derived mesenchymal stem cells (BMSCs) may be beneficial in the fight against osteoporosis (OP) effects. Inokosterone (IS) is a major active constituent of Achyranthis bidentatae radix (ABR), which stimulates osteogenic differentiation of mouse embryonic osteoblasts. This study aims to investigate effect of IS on OP using osteogenic differentiated BMSCs and ovariectomy (OVX)-induced OP rats. The BMSCs were treated with 50, 100, or 200 mg/L IS and OP rats were given 2 or 4 mg/kg of IS by gavage. Cell viability, the osteogenic differentiation marker protein expression level, and mineralization were observed. This study proved that IS improved cell viability, osteogenic differentiation, and cellular mineralization in BMSCs and raised expression levels of bone morphogenetic protein-2 (BMP2), Smad1, runt-related transcription factor 2 (RUNX2), collagen I, ALP, and OCN. By BMP2 knockdown/overexpression, this study also proved the BMP2 signaling pathway activation is a potential biological mechanism of IS to improve osteogenic differentiation and mineralization in osteogenic differentiated BMSCs. In OVX-induced OP rats, IS was observed to antagonize bone loss, improve osteogenic differentiation marker protein expression levels, and activate BMP-2, smad1, and RUNX2. These findings provide scientific support for further investigation of the biological mechanisms of IS in ameliorating OP. • In vitro , Inokosterone (IS) improved viability and osteogenic differentiation of BMSCs. • In vivo , IS antagonized bone loss of ovariectomy (OVX)-induced OP rats. • BMP2 knockdown/overexpression suggested that IS improve osteoporosis through BMP-2. [ABSTRACT FROM AUTHOR]

Nonalcoholic fatty liver disease (NAFLD) is a significant etiological factor in liver-related diseases, which can lead to severe consequences such as steatohepatitis, cirrhosis and death. Cdh1 is considered as a crucial protein involved in cell cycle regulation. The purpose of this study is to explore the biological role of Cdh1 in NAFLD. NAFLD cell model was established, and L02 cells and AML12 cells were infected by shRNA lentivirus with Cdh1 knockdown in vitro, and the effect of Cdh1 deletion on cell lipid deposition was evaluated. The effects of Cdh1 deletion on Akt phosphorylation and PPAR/PGC-1α signaling pathway in L02 cells were examined. In addition, the NAFLD mouse model was constructed, and the conditional knockout mice of Cdh1 were selected to verify the results. In vitro experiments showed that the Cdh1 deletion enhanced cell lipid deposition. In vivo experiments showed that conditional knockdown of Cdh1 aggravated fatty degeneration and damage of liver in mice. Cdh1 deletion promotes Akt phosphorylation and inhibits PPAR/PGC-1α signaling pathway in L02 cells. Conditional knockout of Cdh1 down-regulates PPAR/PGC-1α signaling pathway in NAFLD mouse model. The deletion of Cdh1 may promote Akt phosphorylation by up-regulating Skp2 and inhibit the PPAR/PGC-1α signaling pathway. Cdh1 serves a protective function in the occurrence and progression of NAFLD. • The deletion of Cdh1 enhanced cell lipid deposition. • Conditional knockout of Cdh1 aggravated fatty degeneration and damage of liver. • The deletion of Cdh1 may promote Akt phosphorylation by up-regulating Skp2. • Conditional knockout of Cdh1 down-regulates PPAR/PGC-1α signaling pathway. [ABSTRACT FROM AUTHOR]

The research and development of pharmaceutical intervention is insufficient for the frail older adults, especially in preclinical stage for the frail individuals with osteoporosis. Garlic exerts an antiosteoporotic effect and its vital component allicin could protect organisms against aging. The present study aimed to investigate the effect of long-term intragastric administration of allicin (low dose of 4 mg·kg-1·d-1; middle dose of 8 mg·kg-1·d-1; high dose of 16 mg·kg-1·d-1) on frailty with osteoporosis in aging male Fischer 344 rats. Frailty was assessed with a 27-item frailty index based on quantifying health-related deficits in adult male rats varied from 13 to 21 months and in control rats from 6 to 9 months. Osteoporosis was appraised by bone mineral density detected by dual-energy X-ray absorptiometry, biomechanical properties measured by a three-point bending test, and bone metabolic analysis using ELISA. Allicin could attenuate frailty index scores by reducing the accumulation of health deficits in aging male Fischer 344 rats. Meanwhile, allicin could protect against senile osteoporosis, and the underlying mechanism may involve in increasing low bone turnover through elevation of both bone formation and bone resorption, and subsequently lead to increase of bone mineral density, contributing to reversing deleterious bone biomechanical features associated with aging. The present study reveals firstly that long-term oral administration with allicin attenuated frailty with osteoporosis during the process of aging, which provides a preclinical evidence for intervention of frailty. [ABSTRACT FROM AUTHOR]

Abstract Surface chemistry and topography can determinatively affect the osseointegration of dental implants. Strontium (Sr) has a significant effect on the promotion of bone formation and inhibitation of bone resorption. The emphasis of this study lies on the evaluation of a new surface treatment that aims to improve the early osseointegration of dental implantation both in vitro and in vivo. A hydrothermal method was used to prepare an SrTiO 3 incorporation on sandblasted large-grit double acid-etched (SLA) titanium surfaces in SrCl 2 solution. The composition and morphology of the SrTiO 3 doped surface were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy，and scanning electron microscopy. In addition, the external release figure of Sr was examined by inductively coupled plasma mass spectrometry. The proliferation, adhesion and differentiation of MC3T3-E1 cells on this surface were evaluated in vitro and presented a significant increase in SLA-Sr group compared with that in SLA group. An in vivo study in 24 New Zealand rabbits indicated a remarkable growth in the volume of direct bone-to-implant contact and peri-implant bone in SLA-Sr group, which were compared with SLA group after 3 and 6 weeks, and removal torque tests exhibited a higher torque removal value of SLA-Sr implants. The study gave the result that the biological effect of SLA-Sr implants was significantly superior to that of the SLA implants at the early stage of osseointegration. Highlights • SrTiO 3 was incorporated on sandblasted large-grit double acid-etched (SLA) titanium surfaces by hydrothermal method. • SrTiO 3 incorporated SLA surface promoted the bone formation in vitro and in vivo, especially at the early stage of osseointegration. • The work will have a remarkably clinical potential and take a step forward in respect to the current clinical practice. [ABSTRACT FROM AUTHOR]

An overview of gaseous ion/surface collisions is presented, with special emphasis on the behavior of polyatomic projectile ions at hyperthermal collision energies (1–100 eV) and the instrumentation needed for such studies. The inelastic and reactive processes occurring during ion/surface collisions are described in terms of several archetypes, viz., elastic and quasielastic scattering, chemical sputtering leading to release of surface material, inelastic scattering leading to surface-induced dissociation (SID) of the projectile, ion/surface reactions, and soft landing. Parameters that are important in ion/surface interactions are discussed, including the interaction time, the conversion of translational to internal energy, the translational energies of the scattered ions, the effects of scattering angle, and the influence of the nature of the surface. Different types of tandem mass spectrometers, built specifically to study ion/surface collision phenomena, are discussed and the advantages and disadvantages of the individual designs are compared. The role of SID as a technique in bioanalytical mass spectrometry is illustrated and this inelastic collision experiment is compared and contrasted with gas-phase collision-induced dissociation, the standard method of tandem mass spectrometry. Special emphasis is placed on reactive scattering including the use of ion/surface reactions for surface chemical analysis and for surface chemical modification. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]