Role of the porous structure of the bioceramic scaffolds in bone tissue engineering

The porous structure of biomaterials plays a critical role in improving the efficiency of biomaterials in tissue engineering. Here we fabricate successfully porous bioceramics with accurately controlled pore parameters, and investigate the effect of pore parameters on the mechanical property, the cell seeding proliferation and the vascularization of the scaffolds. This study shows that the porosity play an important role on the mechanical property of the scaffolds, which is affected not only by the macropores size, but also by the interconnections of the scaffolds. Larger pores are beneficial for cell growth in scaffolds. In contrast, the interconnections do not affect cell growth much. The interconnections appear to limit the number of blood vessels penatrating through adjacent pores, and both the pores size and interconnections can determine the size of blood vessels. The results may be referenced on the selective design of porous structure of biomaterials to meet the specificity of biological application

Noncommutative Geometry of Lattice and Staggered Fermions

Differential structure of a d-dimensional lattice, which is essentially a noncommutative exterior algebra, is defined using reductions in first order and second order of universal differential calculus in the context of noncommutative geometry (NCG) developed by Dimakis et al. This differential structure can be realized adopting a Dirac-Connes operator proposed by us recently within Connes' NCG. With matrix representations being specified, our Dirac-Connes operator corresponds to staggered Dirac operator, in the case that dimension of the lattice equals to 1, 2 and 4.Comment: Latex; 13 pages; no figures. References added. Accepted by Phys. Lett.

Modeling the effects of satiation on the feeding rate of a colonial suspension feeder, Acanthogorgia vegae, in a circulating system under lab conditions

(2002) Modeling the effects of satiation on the feeding rate of a colonial suspension feeder, Acanthogorgia vegae, in a circulating system under lab conditions. Zoological Studies 41(4): 355-365. We developed a mathematical model, based on observations relating to feeding behavior of the gorgonian Acanthogorgia vegae, to characterize the feeding rates of colonial suspension feeders in a circulating system. We found that simultaneously none of all the polyps belonging to the same colony of A. vegae showed a feeding response after capturing a certain amount of Artemia nauplii. Equations in terms of the satiation factor were derived to predict feeding rates of colonial suspension feeders. Flume experiments were conducted under different ambient flow regimes to test the application of the equations. Good agreement between the results of the experiments and the predictions was evident. The results of this study show that satiation is an important factor influencing the feeding rate of colonial suspension feeders with an abundant food supply and a closed system of water. Furthermore, our study shows that the feeding rate of colonial suspension feeders in a circulating system can easily be calculated from the residual number of prey items at various times, even when the initial numbers of prey items and feeding animals are unknown. Our model is useful as a good methodological tool to estimate the feeding rate of colonial suspension feeders in the laboratory or aquacultural environments

String Resonances at Hadron Colliders

[Abridged] We consider extensions of the standard model based on open strings ending on D-branes. Assuming that the fundamental string mass scale M_s is in the TeV range and that the theory is weakly coupled, we discuss possible signals of string physics at the upcoming HL-LHC run (3000 fb^{-1}) with \sqrt{s} = 14 TeV, and at potential future pp colliders, HE-LHC and VLHC, operating at \sqrt{s} = 33 and 100 TeV, respectively. In such D-brane constructions, the dominant contributions to full-fledged string amplitudes for all the common QCD parton subprocesses leading to dijets and \gamma + jet are completely independent of the details of compactification, and can be evaluated in a parameter-free manner. We make use of these amplitudes evaluated near the first (n=1) and second (n=2) resonant poles to determine the discovery potential for Regge excitations of the quark, the gluon, and the color singlet living on the QCD stack. We show that for string scales as large as 7.1 TeV (6.1 TeV), lowest massive Regge excitations are open to discovery at 5\sigma in dijet (\gamma + jet) HL-LHC data. We also show that for n=1, the dijet discovery potential at HE-LHC and VLHC exceedingly improves: up to 15 TeV and 41 TeV, respectively. To compute the signal-to-noise ratio for n=2 resonances, we first carry out a complete calculation of all relevant decay widths of the second massive level string states. We demonstrate that for string scales M_s <~ 10.5 TeV (M_s <~ 28 TeV), detection of n=2 Regge recurrences at HE-LHC (VLHC) would become the smoking gun for D-brane string compactifications. Our calculations have been performed using a semi-analytic parton model approach which is cross checked against an original software package. The string event generator interfaces with HERWIG and Pythia through BlackMax. The source code is publically available in the hepforge repository.Comment: References adde

Bioactive Eunicellin-Based Diterpenoids from the Soft Coral Cladiella krempfi

Four new eunicellin-based diterpenoids, krempfielins A–D (1–4), along with two known compounds (5 and 6) have been isolated from a soft coral Cladiella krempfi. The structures of the new metabolites were elucidated by extensive spectroscopic analysis and by comparison with spectroscopic data of related known compounds. Compounds 5 and 6 were shown to exhibit cytotoxicity against a limited panel of cancer cell lines. Furthermore, compounds 2, 3, 5 and 6 were shown to exert significant in vitro anti-inflammatory activity against LPS-stimulated RAW264.7 macrophage cells

Reproductive isolation among Acropora Species (Scleractinia: Acroporidae) in a marginal coral assemblage

Hybridization was proposed as being an important source of evolutionary novelty in broadcast-spawning reef-building corals. In addition, hybridization was hypothesized to be more frequent at the periphery of species' ranges and in marginal habitats. We tested the potential for hybridization in 2 ways: observations of the time of spawning and non-choice interspecific fertilization experiments of 4 sympatric Acropora species in a non-reefal coral assemblage at Chinwan Inner Bay (CIB), Penghu Is., Taiwan. We found that colonies of more than 1 species rarely released gametes at the same time, thus limiting the opportunities for cross-fertilization in the wild. On the few occasions when different species released gametes in synchrony, interspecific fertilization in experimental crosses was uniformly low (the proportion of eggs fertilized ranged 0%-4.58% with a mode of 0%), and interspecific-crossed embryos ceased development and died within 12 h after initially being fertilized. Ecological and experimental analyses indicated that reproductive isolation exists in these 4 Acropora species even though they have the opportunities to spawn synchronously, suggesting that hybridization is not very frequent in this marginal coral habitat at CIB

Evaluation of molecular makers for species phylogeny of genus Acropora (Cnidaria; Scleractinia; Acroporidae)

Acropora is the most speciose genus in coral reef with 113 species currently described. Diversified morphology and potential of cross-species hybridization have drawn our attention in defining the species boundary, constructing species-level phylogeny, and inferring mechanism of speciation for this genus. Although endeavours have been taking in developing molecular markers in the last decade, several unique features such as slow evolution of mitochondrial genome and abundant ribosomal pseudogenes of Acropora neither provide little resolution for phylogenetic inference, nor equivocal conclusions in contrast to phylogenies based on fossil records and morphological characters. In this study, we evaluated 4 molecular markers, including mitochondrial cytochrome b gene (Cytb), mitochondrial intergenic spacer spanning between Cytb and ND gene (mtigs), mini-collagen intron 2 (mci2), and nuclear histone 2a and 2b gene (H2ab), for constructing species phylogeny of genus Acropora. All the 4 loci supported the two subgenera, lsopora and Acropora, as two distinct evolutionary lineages, and relocated Acropora togianensis as the fifth species in the• subgenus lsopora. However, Cytb, mtigs, and mci2 suffering from either low variability or sharing unsorted polymorphisms between the Caribbean and Indo-Pacific species provided no further resolution in resolving phylogeny in subgenus Acropora. In contrast, phylogeny constructed based on h2ab gene using Bayesian approach supported, in part, to Wallace (1999), that A. humilis group and A. austera form the basal clades of morphological phylogeny. The utility of nuclear coding genes in. resolving. species phylogeny of Acropora is highlighted

Essential role of microglia in the fast antidepressant action of ketamine and hypidone hydrochloride (YL-0919)

Introduction: Intracerebral microglia play a vital role in mediating central immune response, neuronal repair and synaptic pruning, but its precise role and mechanism in fast action of antidepressants have remained unknown. In this study, we identified that the microglia contributed to the rapid action of antidepressants ketamine and YL-0919.Methods: The depletion of microglia was achieved with the diet containing the colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 in mice. The tail suspension test (TST), forced swimming test (FST) and novelty suppressed feeding test (NSFT) were employed to evaluate the rapid acting antidepressant behavior of ketamine and YL-0919 in the microglia depletion model. The number of microglia in the prefrontal cortex (PFC) was assayed by the immunofluorescence staining. The expressions of synaptic proteins (synapsin-1, PSD-95, GluA1) and brain-derived neurotrophic factor (BDNF) in the PFC were tested by Western blot.Results: The immobility duration in FST and the latency to feed in NSFT were shortened 24 h after an intraperitoneal (i.p.) injection of ketamine (10 mg/kg). The microglial depletion of PLX3397 blocked the rapid antidepressant-like effect of ketamine in mice. In addition, the immobility time in TST and FST as well as latency to feed in NSFT were reduced 24 h after the intragastric (i.g.) administration of YL-0919 (2.5 mg/kg, administered for 5–6 consecutive days), and the rapid antidepressant effect of YL-0919 was also blocked by the microglial depletion using PLX5622. About 92% of microglia in the prefrontal cortex was depleted in PLX5622 diet-fed mice, while both ketamine and YL-0919 promoted proliferation on the remaining microglia. YL-0919 significantly increased the protein expressions of synapsin-1, PSD-95, GluA1 and BDNF in the PFC, all of which could be blocked by PLX5622.Conclusion: These results suggested the microglia underlying the rapid antidepressant-like effect of ketamine and YL-0919, and microglia would likely constitute in the rapid enhancing impact of synaptic plasticity in the prefrontal cortex by YL-0919