Evaluation of capillaries with different inner coatings for DNA analysis using dilute polymer solutions by capillary electrophoresis

In this work three capillary columns, one with uncoated inner wall and two with covalently-bound internal coatings - poly(vinyl alcohol) (PVA) and poly(dimethylacrylamide) (PDMA) - both covalently covered - were used to separate DNA fragments and compared to DNA separation using replaceable polymer solutions. The separations were performed using hydroxyethylcellulose (HEC) (90-105 kDa) in concentrations ranging from 0.00 to 2.00% m/v. The results indicated that the separation efficiency was higher in the PVA capillary than in the PDMA in all evaluated concentrations of HEC. In addition, higher resolution was also observed in PVA-coated capillary since in PDMA the shape of the peaks was not reproducible when subsequent runs were performed. Contrary to what has previously been reported in the literature, no reasonable separation was possible in bare fused silica.

Exact time-dependent solutions for a self-regulating gene

The exact time-dependent solution for the stochastic equations governing the behavior of a binary self-regulating gene is presented. Using the generating function technique to rephrase the master equations in terms of partial differential equations, we show that the model is totally integrable and the analytical solutions are the celebrated confluent Heun functions. Self-regulation plays a major role in the control of gene expression, and it is remarkable that such a microscopic model is completely integrable in terms of well-known complex functions.

Efficacy of sweet solutions for analgesia in infants between 1 and 12 months of age: a systematic review

Objective To compare the efficacy of oral sweet solutions to water or no treatment in infants aged 1-12 months during immunisation. Methods Randomised controlled trials (RCTs) were retrieved through internet searches or manual searches of reference lists. Search terms included newborn, infant, pain, sucrose and alternative names for sweet solutions. Summary estimates with 95% CIs were calculated and included relative risk (RR), risk difference (RD) and number needed to treat to benefit (NNTB) for dichotomous outcomes, and weighted mean differences (WMD) for continuous outcomes. Where pooling of results was not possible, a narrative summary of study results is presented. Results Of the 695 studies identified, 14 RCTs with 1674 injections met the inclusion criteria. Sucrose or glucose, compared to water or no treatment decreased crying during or following immunisation in 13 of the 14 studies. Infants receiving 30% glucose (three trials, 243 infants) had a decreased RR in crying incidence following immunisation (typical RR 0.80, 95% CI 0.69 to 0.93; RD -0.17, 95% CI -0.29 to -0.05; NNTB 6, 95% CI 3 to 20). With sucrose or glucose, there was a 10% WMD reduction in proportion of crying time (95% CI - 18 to - 2) and a 12 s reduction in crying duration (95% CI - 23 to -0.7 s). An optimal dose of sucrose or glucose could not be ascertained due to the varied volumes and concentrations used. Conclusion Infants aged 1-12 months administered sucrose or glucose before immunisation had moderately reduced incidence and duration of crying. Healthcare professionals should consider using sucrose or glucose before and during immunisation.

Synthesis of diaryl selenides using electrophilic selenium species and nucleophilic boron reagents in ionic liquids

We described herein the use of imidazolium ionic liquids [bmim]PF(6) and [bmim]BF(4) in the selective, metal and catalyst-free synthesis of unsymmetrical diaryl selenides by electrophilic substitution in arylboron reagents with arylselenium halides (Cl and Br) at room temperature. This is a general substitution reaction and it was performed with arylboronic acids or potassium aryltrifluoroborates bearing electron-withdrawing or electron-donating groups, affording the corresponding diaryl selenides in good to excellent yields. The ionic liquid [bmim][PF(6)] was easily recovered and utilized for further substitution reactions.

GLOBAL SOLUTIONS FOR ABSTRACT FUNCTIONAL DIFFERENTIAL EQUATIONS WITH NONLOCAL CONDITIONS

In this paper we study the existence of global solutions for a class of abstract functional differential equation with nonlocal conditions. An application is considered.

Weighted S-Asymptotically omega-Periodic Solutions of a Class of Fractional Differential Equations

We study the existence of weighted S-asymptotically omega-periodic mild solutions for a class of abstract fractional differential equations of the form u' = partial derivative (alpha vertical bar 1)Au + f(t, u), 1 < alpha < 2, where A is a linear sectorial operator of negative type.

Data collapse, scaling functions, and analytical solutions of generalized growth models

We consider a nontrivial one-species population dynamics model with finite and infinite carrying capacities. Time-dependent intrinsic and extrinsic growth rates are considered in these models. Through the model per capita growth rate we obtain a heuristic general procedure to generate scaling functions to collapse data into a simple linear behavior even if an extrinsic growth rate is included. With this data collapse, all the models studied become independent from the parameters and initial condition. Analytical solutions are found when time-dependent coefficients are considered. These solutions allow us to perceive nontrivial transitions between species extinction and survival and to calculate the transition's critical exponents. Considering an extrinsic growth rate as a cancer treatment, we show that the relevant quantity depends not only on the intensity of the treatment, but also on when the cancerous cell growth is maximum.

Ionic and Histological Studies of Salivary Glands in Rats with Diabetes and Their Glycemic State After Laser Irradiation

Objectives: To evaluate the effect of laser irradiation (LI) on the glycemic state and the histological and ionic parameters of the parotid and submandibular glands in rats with diabetes. Methods: One hundred twenty female rats were divided into eight groups. Diabetes was induced by administration of streptozotocin and confirmed later according to results of glycemia testing. Twenty-nine days after the induction, the parotid and submandibular glands of the rats were irradiated with 5, 10, and 20 J/cm(2) using a laser diode (660nm/100mW) (without diabetes: C5, C10, and C20; with diabetes: D5, D10, and D20, respectively). On the following day, the rats were euthanized, and blood glucose determined. Histological and ionic analyses were performed. Results: Rats with diabetes without irradiation (D0) showed lipid droples accumulation in the parotid gland, but accumulation decreased after 5, 10, and 20 J/cm(2) of laser irradiation. A decrease in fasting glycemia level from 358.97 +/- 56.70 to 278.33 +/- 87.98mg/dL for D5 and from 409.50 +/- 124.41 to 231.80 +/- 120.18 mg/dL for D20 (p < 0.05) was also observed. Conclusion: LI should be explored as an auxiliary therapy for control of complications of diabetes because it can alter the carbohydrate and lipid metabolism of rats with diabetes.

Effect of a Single Application of TiF(4) and NaF Varnishes and Solutions Combined with Nd:YAG Laser Irradiation on Enamel Erosion in Vitro

Objective: This in vitro study aimed to analyze the influence of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser irradiation on the efficacy of titanium tetrafluoride (TiF(4)) and sodium fluoride (NaF) varnishes and solutions to protect enamel against erosion. Background data: The effect of Nd:YAG laser irradiation on NaF and AmF was analyzed; however, there is no available data on the interaction between Nd:YAG laser irradiation and TiF(4). Methods: Bovine enamel specimens were pre-treated with NaF varnish, TiF(4) varnish, NaF solution, TiF(4) solution, placebo varnish, Nd:YAG (84.9 J/cm(2)), Nd:YAG prior to or through NaF varnish, Nd:YAG prior to or through TiF(4) varnish, Nd:YAG prior to or through NaF solution, Nd:YAG prior to or through TiF(4) solution, and Nd:YAG prior to or through placebo varnish. Controls remained untreated. Ten specimens in each group were then subjected to an erosive demineralization (Sprite Zero, 4x90 s/day) and remineralization (artificial saliva, between the erosive cycles) cycling for 5 days. Enamel loss was measured profilometrically (mu m). Additionally, treated but non-eroded specimens were additionally analyzed by scanning electron microscope (SEM) (each group n-2). The data were statistically analyzed by ANOVA and Tukey's post-hoc test (p < 0.05). Results: Only TiF(4) varnish (1.8 +/- 0.6 mu m), laser prior to TiF(4) varnish (1.7 +/- 0.3 mu m) and laser prior to TiF(4) solution (1.4 +/- 0.3 mu m) significantly reduced enamel erosion compared to the control (4.1 +/- 0.6 mu m). SEM pictures showed that specimens treated with TiF(4) varnish presented a surface coating. Conclusions: Nd:YAG laser irradiation was not effective against enamel erosion and it did not have any influence on the efficacy of F, except for TiF(4) solution. On the other hand, TiF(4) varnish protected against enamel erosion, without the influence of laser irradiation.

SOLITON SOLUTIONS TO SYSTEMS OF COUPLED SCHRODINGER EQUATIONS OF HAMILTONIAN TYPE

We study the existence of positive solutions of Hamiltonian-type systems of second-order elliptic PDE in the whole space. The systems depend on a small parameter and involve a potential having a global well structure. We use dual variational methods, a mountain-pass type approach and Fourier analysis to prove positive solutions exist for sufficiently small values of the parameter.

Analytical solutions for Tokamak equilibria with reversed toroidal current

In tokamaks, an advanced plasma confinement regime has been investigated with a central hollow electric current with negative density which gives rise to non-nested magnetic surfaces. We present analytical solutions for the magnetohydrodynamic equilibria of this regime in terms of non-orthogonal toroidal polar coordinates. These solutions are obtained for large aspect ratio tokamaks and they are valid for any kind of reversed hollow current density profiles. The zero order solution of the poloidal magnetic flux function describes nested toroidal magnetic surfaces with a magnetic axis displaced due to the toroidal geometry. The first order correction introduces a poloidal field asymmetry and, consequently, magnetic islands arise around the zero order surface with null poloidal magnetic flux gradient. An analytic expression for the magnetic island width is deduced in terms of the equilibrium parameters. We give examples of the equilibrium plasma profiles and islands obtained for a class of current density profile. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3624551]

Synchrotron X-ray powder diffraction and extended X-ray absorption fine structure spectroscopy studies on nanocrystalline ZrO(2)-CaO solid solutions

The crystal structure and the local atomic order of a series of nanocrystalline ZrO(2)-CaO solid solutions with varying CaO content were studied by synchrotron radiation X-ray powder diffraction and extended X-ray absorption fine structure (EXAFS) spectroscopy. These samples were synthesized by a pH-controlled nitrate-glycine gel-combustion process. For CaO contents up to 8 mol%, the t' form of the tetragonal phase (c/a > 1) was identified, whereas for 10 and 12 mol% CaO, the t '' form (c/a=1; oxygen anions displaced from their ideal positions in the cubic phase) was detected. Finally, the cubic phase was observed for solid solutions with CaO content of 14 mol% CaO or higher. The t'/t '' and t ''/cubic compositional boundaries were determined to be at 9 (1) and 13 (1) mol% CaO, respectively. The EXAFS study demonstrated that this transition is related to a tetragonal-to-cubic symmetry change of the first oxygen coordination shell around the Zr atoms.

High-temperature X-ray powder diffraction study of the tetragonal-cubic phase transition in nanocrystalline, compositionally homogeneous ZrO2-CeO2 solid solutions

Crystal structure of compositionally homogeneous, nanocrystalline ZrO2-CeO2 solutions was investigated by X-ray powder diffraction as a function of temperature for compositions between 50 and 65 mol % CeO2 center dot ZrO2-50 and 60 mol % CeO2 solid solutions, which exhibit the t'-form of the tetragonal phase at room temperature, transform into the cubic phase in two steps: t'-to-t '' followed by t ''-to-cubic. But the ZrO2-65 mol % CeO2, which exhibits the t ''-form, transforms directly to the cubic phase. The results suggest that t'-to-t '' transition is of first order, but t ''-to-cubic seems to be of second order. (C) 2008 International Centre for Diffraction Data.

Synchrotron X-ray powder diffraction study of the tetragonal-cubic phase transition in nanostructured ZrO2-Sc2O3 solid solutions

The transition between tetragonal and cubic phases in nanostructured ZrO2-Sc2O3 solid solutions by high-temperature X-ray powder diffraction using synchrotron radiation is presented. ZrO2-8 and 11 mol% Sc2O3 nanopowders that exhibit the t'- and t ''-forms of the tetragonal phase, respectively, were synthesized by a stoichiometric nitrate-lysine gel-combustion route. The average crystallite size treated at 900 degrees C was about 25 nm for both compositions. Our results showed that t'-t '' and t ''-cubic transitions take place for the 8 and 11 mol% Sc2O3 samples, respectively. (C) 2008 International Centre for Diffraction Data.

Phase transitions and spatially ordered counterion association in ionic-lipid membranes: A statistical model

We propose a statistical model to account for the gel-fluid anomalous phase transitions in charged bilayer- or lamellae-forming ionic lipids. The model Hamiltonian comprises effective attractive interactions to describe neutral-lipid membranes as well as the effect of electrostatic repulsions of the discrete ionic charges on the lipid headgroups. The latter can be counterion dissociated (charged) or counterion associated (neutral), while the lipid acyl chains may be in gel (low-temperature or high-lateral-pressure) or fluid (high-temperature or low-lateral-pressure) states. The system is modeled as a lattice gas with two distinct particle types-each one associated, respectively, with the polar-headgroup and the acyl-chain states-which can be mapped onto an Ashkin-Teller model with the inclusion of cubic terms. The model displays a rich thermodynamic behavior in terms of the chemical potential of counterions (related to added salt concentration) and lateral pressure. In particular, we show the existence of semidissociated thermodynamic phases related to the onset of charge order in the system. This type of order stems from spatially ordered counterion association to the lipid headgroups, in which charged and neutral lipids alternate in a checkerboard-like order. Within the mean-field approximation, we predict that the acyl-chain order-disorder transition is discontinuous, with the first-order line ending at a critical point, as in the neutral case. Moreover, the charge order gives rise to continuous transitions, with the associated second-order lines joining the aforementioned first-order line at critical end points. We explore the thermodynamic behavior of some physical quantities, like the specific heat at constant lateral pressure and the degree of ionization, associated with the fraction of charged lipid headgroups.