The signals of FGFs on the neurogenesis of embryonic stem cells

<p>Abstract</p> <p>Background</p> <p>Neural induction is a complex process and the detailed mechanism of FGF-induced neurogenesis remains unclear.</p> <p>Methods</p> <p>By using a serum-free neural induction method, we showed that FGF1 dose-dependently promoted the induction of Sox1/N-cadherin/nestin triple positive cells, which represent primitive neuroblasts, from mouse embryonic stem (ES) cells.</p> <p>Results</p> <p>We demonstrated that FGF1, FGF2, and FGF4, but not FGF8b, enhanced this neurogenesis. Especially, FGF-enhanced neurogenesis is not mediated through the rescue of the apoptosis or the enhancement of the proliferation of Sox1⁺cells. We further indicated that the inactivation of c-Jun N-terminal kinase-1 (JNK-1) and extracellular signal-related kinase-2 (ERK-2), but not p38 mitogen-activated protein kinase (MAPK), inhibited the neural formation through the inhibition of ES differentiation, but not through the formation of endomesodermal cells.</p> <p>Conclusions</p> <p>These lines of evidence delineated the roles of FGF downstream signals in the early neural differentiation of ES cells.</p

Topological effects at short antiferromagnetic Heisenberg chains

The manifestations of topological effects in finite antiferromagnetic Heisenberg chains is examined by density matrix renormalization group technique in this paper. We find that difference between integer and half-integer spin chains shows up in ground state energy per site when length of spin chain is longer than $\sim\xi$, where $\xi\sim\exp(\pi S)$ is a spin-spin correlation length, for spin magnitude S up to 5/2. For open chains with spin magnitudes $S=5/2$ to S=5, we verify that end states with fractional spin quantum numbers $S'$ exist and are visible even when the chain length is much smaller than the correlation length $\xi$. The end states manifest themselves in the structure of the low energy excitation spectrum.Comment: 4 pages, 6 figure

Bulk Versus Edge in the Quantum Hall Effect

The manifestation of the bulk quantum Hall effect on edge is the chiral anomaly. The chiral anomaly {\it is} the underlying principle of the ``edge approach'' of quantum Hall effect. In that approach, \sxy should not be taken as the conductance derived from the space-local current-current correlation function of the pure one-dimensional edge problem.Comment: 4 pages, RevTex, 1 postscript figur

Comparison of Differential Pulse Voltammetry (DPV)-a new method of carbamazepine analysis-with Fluorescence Polarization Immunoassay (FPIA)

Carbamazepine is a widely used anti-epileptic drug with narrow therapeutic range. Many methods have been developed for monitoring the serum drug level. Differential pulse voltammetry (DPV), an electrochemical method advantaged by simple, inexpensive, and relatively short analysis time, has recently been developed for carbamazepine detection. We used a newly developed DPV method with glassy carbon as a working electrode to determine the carbamazepine level. The performance of DPV is compared with the widely used fluorescence polarization immunoassay (FPIA) technique in precision, accuracy, linearity and detection limit. The precision, linearity and accuracy of the DPV and FPIA techniques were comparable at most clinical used levels. The detection limit was 1 mu g/mL for the DPV technique and 0.5 mu g/mL for the FPIA technique. The performance of the DPV technique was within the FDA guidelines for bioanalytical methods, which ensures the clinical applicability of the DPV technique. The DPV technique may have the potential to be a good alternative for carbamazepine analysis

Serine-385 phosphorylation of inwardly rectifying K(+) channel subunit (Kir6.2) by AMP-dependent protein kinase plays a key role in rosiglitazone-induced closure of the K(ATP) channel and insulin secretion in rats

Rosiglitazone, an insulin sensitiser, not only improves insulin sensitivity but also enhances insulin secretory capacity by ameliorating gluco- and lipotoxicity in beta cells. Rosiglitazone can stimulate insulin secretion at basal and high glucose levels via a phosphatidylinositol 3-kinase (PI3K)-dependent pathway. We hypothesised that regulation of phosphorylation of the ATP-sensitive potassium (K(ATP)) channel might serve as a key step in the regulation of insulin secretion. Insulin secretory responses were studied in an isolated pancreas perfusion system, cultured rat islets and MIN6 and RINm5F beta cells. Signal transduction pathways downstream of PI3K were explored to link rosiglitazone to K(ATP) channel conductance with patch clamp techniques and insulin secretion measured by ELISA. Rosiglitazone stimulated AMP-activated protein kinase (AMPK) activity and induced inhibition of the K(ATP) channel conductance in islet beta cells; both effects were blocked by the PI3K inhibitor LY294002. Following stimulation of AMPK by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR), a pharmacological activator, both AICAR-stimulated insulin secretion and inhibition of K(ATP) channel conductance were unaffected by LY294002, indicating that AMPK activation occurs at a site downstream of PI3K activity. The serine residue at amino acid position 385 of Kir6.2 was found to be the substrate phosphorylation site of AMPK when activated by rosiglitazone or AICAR. Our data indicate that PI3K-dependent activation of AMPK is required for rosiglitazone-stimulated insulin secretion in pancreatic beta cells. Phosphorylation of the Ser(385) residue of the Kir6.2 subunit of the K(ATP) channel by AMPK may play a role in insulin secretion

Hamiltonian theory of gaps, masses and polarization in quantum Hall states: full disclosure

I furnish details of the hamiltonian theory of the FQHE developed with Murthy for the infrared, which I subsequently extended to all distances and apply it to Jain fractions \nu = p/(2ps + 1). The explicit operator description in terms of the CF allows one to answer quantitative and qualitative issues, some of which cannot even be posed otherwise. I compute activation gaps for several potentials, exhibit their particle hole symmetry, the profiles of charge density in states with a quasiparticles or hole, (all in closed form) and compare to results from trial wavefunctions and exact diagonalization. The Hartree-Fock approximation is used since much of the nonperturbative physics is built in at tree level. I compare the gaps to experiment and comment on the rough equality of normalized masses near half and quarter filling. I compute the critical fields at which the Hall system will jump from one quantized value of polarization to another, and the polarization and relaxation rates for half filling as a function of temperature and propose a Korringa like law. After providing some plausibility arguments, I explore the possibility of describing several magnetic phenomena in dirty systems with an effective potential, by extracting a free parameter describing the potential from one data point and then using it to predict all the others from that sample. This works to the accuracy typical of this theory (10 -20 percent). I explain why the CF behaves like free particle in some magnetic experiments when it is not, what exactly the CF is made of, what one means by its dipole moment, and how the comparison of theory to experiment must be modified to fit the peculiarities of the quantized Hall problem

A CsI(Tl) Scintillating Crystal Detector for the Studies of Low Energy Neutrino Interactions

Scintillating crystal detector may offer some potential advantages in the low-energy, low-background experiments. A 500 kg CsI(Tl) detector to be placed near the core of Nuclear Power Station II in Taiwan is being constructed for the studies of electron-neutrino scatterings and other keV-MeV range neutrino interactions. The motivations of this detector approach, the physics to be addressed, the basic experimental design, and the characteristic performance of prototype modules are described. The expected background channels and their experimental handles are discussed.Comment: 34 pages, 11 figures, submitted to Nucl. Instrum. Method

D-concurrence bounds for pair coherent states

The pair coherent state is a state of a two-mode radiation field which is known as a state with non-Gaussian wave function. In this paper, the upper and lower bounds for D-concurrence (a new entanglement measure) have been studied over this state and calculated.Comment: 11 page

Strategies to augment non-immune system based defence mechanisms against gastrointestinal diseases in pigs

AbstractOur study addresses the first two weeks of the weaning period of piglets during which stressful physiological and environmental conditions experienced by the animals can promote the proliferation of pathogens in the digestive tract. The aim of the study was to identify new feeding strategies that result in boosting the gastrointestinal tract (GIT) microbiota of piglets and improve growth performance, reducing the negative impact of weaning. In order to identify a new synbiotic combination, 12 new putative probiotic strains of Bifidobacterium spp. and three non-digestible oligosaccharides [NDO] were screened in newly weaned piglets. The ability to increase the level of autochthonous bifidobacteria and improve growth performance were assessed. Bifidobacteria strains with a similar ability to develop in the hindgut showed a different effect on piglet performance depending on the dose in which they were provided. Our data support the idea that the presence of fructo-oligosaccharides would stimulate the occurrence of bifidobacteria in the caecum. It was shown that dietary intake of nitrate can generate salivary nitrite, which in turn is acidified in the stomach and could have antimicrobial activity against swallowed pathogens. The efficacy of the resulting synbiotic formula was improved by adding nitrate as antimicrobial. To enhance probiotic survival during gastric transit, a novel technology of microencapsulation was developed and applied to bacteria. The final synbiotic, containing the strain RA 18 of Bifidobacterium animalis subsp. lactis [1011cfu/day], the prebiotic Actilight® [4% of the diet], and nitrate [150mg KNO3/kg feed/day] was tested in organic weaned piglets reared under field conditions. Results show that the strain Ra 18 had a probiotic effect in organic weaned piglets, as it colonized and remained detectable in faecal samples until two weeks after addition. The use of our synbiotic formula improved weight gain, feed efficiency and health status of the weaned piglets

The Kuiper Belt and Other Debris Disks

We discuss the current knowledge of the Solar system, focusing on bodies in the outer regions, on the information they provide concerning Solar system formation, and on the possible relationships that may exist between our system and the debris disks of other stars. Beyond the domains of the Terrestrial and giant planets, the comets in the Kuiper belt and the Oort cloud preserve some of our most pristine materials. The Kuiper belt, in particular, is a collisional dust source and a scientific bridge to the dusty "debris disks" observed around many nearby main-sequence stars. Study of the Solar system provides a level of detail that we cannot discern in the distant disks while observations of the disks may help to set the Solar system in proper context.Comment: 50 pages, 25 Figures. To appear in conference proceedings book "Astrophysics in the Next Decade