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1.
J Phys Chem A ; 125(17): 3696-3709, 2021 May 06.
Article in English | MEDLINE | ID: mdl-33890788

ABSTRACT

The thermodynamic properties and band gap energies were evaluated for six ortho- and peri-fused polycyclic aromatic hydrocarbons (PAHs): triphenylene; benzo[a]pyrene; benzo[e]pyrene; perylene; benzo[ghi]perylene; coronene. The standard molar enthalpies of formation in the crystalline state and the standard molar enthalpies of sublimation were measured by high precision combustion calorimetry and Knudsen effusion methodology, respectively. The combination of the molar enthalpies of formation in the crystalline state with the respective enthalpies of sublimation was used to evaluate the energetics of the progressive peri-fusion of the aromatic moieties from triphenylene to coronene aiming to investigate the hypothetical superaromaticity character of coronene. The linear trend of the enthalpy of formation in crystalline and gaseous phases in the series (from benzo[e]pyrene to coronene) is an irrefutable indication of a non-superaromaticity character of coronene. High accurate thermodynamic properties of sublimation (volatility, enthalpy, and entropy of sublimation) were derived by the measurement of vapor pressures as a function of temperature, using a Knudsen/quartz crystal effusion methodology. Furthermore, the π-electronic conjugation of these compounds was explored by evaluation of the optical band gaps along with this series of compounds. The morphology of perylene, benzo[ghi]perylene, and coronene thin films, deposited by physical vapor deposition onto transparent conductive oxide substrates (ITO and FTO), was used to analyze the nucleation and growth mechanisms. The morphologies observed were found to be related to the cohesive energy and entropy of the bulk.

2.
Phys Chem Chem Phys ; 22(26): 15022-15034, 2020 Jul 08.
Article in English | MEDLINE | ID: mdl-32597431

ABSTRACT

Photonic and electronic properties exist inherently in ferroelectric barium titanate (BaTiO3); severe luminescence quenching also exists due to the insufficient confinement of excitons. In this sense, high optical emission can only be achieved by its chemical and structural modification. Thin BaTiO3 and Er:BaTiO3 films were grown by the spin coating method on a glass substrate at room temperature. Self-trapping of excitons in the thin BaTiO3 film and its structural modification due to the doping with Er3+ ions (Er:BaTiO3) are verified using scanning confocal fluorescence microscopy (SCFM), where self-trapping excitons never occured in its pure state. By thermal treatment and doping (BaTiO3 and Er:BaTiO3) we obtained localization of the excitons, which would further induce lattice strain around the surface defects, to accommodate the self-trapped excitons. With such a self-trapped state, the structure of BaTiO3 generates broadband emission of several overlapping bands between 1.95 and 2.65 eV at room temperature, while the structure Er:BaTiO3 showed defined emission bands at 2.24 and 2.35 eV, with very weak contributions of the emission due to the self-trapping state. The influence of the variation of the excitation wavelength using 1PE and 2PE on the emission bands of BaTiO3 and Er:BaTiO3 is also investigated. The results of enhanced emission bands suggest a clear dependence of the emission intensity on the excitation energy, where a ∼3 fold enhancement in emission has been demonstrated under Er3+ (1.55 eV) excitation, which can be attributed to effective energy transfer between the Er3+ ions. As a result, it is concluded that the developed BaTiO3 and Er:BaTiO3 can pave the way for future photonic devices.

3.
Pharmazie ; 74(12): 715-720, 2019 12 01.
Article in English | MEDLINE | ID: mdl-31907109

ABSTRACT

A copper(II) complex-loaded castor oil-based nanostructured lipid carrier was evaluated to enhance the poor water solubility of antimicrobial compounds, improving their biological properties and antimicrobial activity against Mycobacterium tuberculosis. Nanostructured lipid carriers were composed of the castor oil, polyoxyethylene 40 stearate and caprylic/capric triglyceride, poloxamer 407, cetyltrimethylammonium bromide and three different copper(II) complexes. The systems were ultrasonicated at an amplitude of 8% for 20 min and an ice bath was used throughout the procedure. The blank nanostructured lipid carrier (F5) and nanostructured lipid carriers loaded with copper(II) complex 1, 2 and 3 (F5.1, F5.2 and F5.3, respectively) for 45 days presented values of mean diameter, poly dispersity index and zeta potential ranging from 186 to 199 nm, 0.14 to 0.2 and 24 to 30 mV, respectively. Atomic force microscopy indicated that the nanostructured lipid carriers were distributed at the nanoscale, corroborating the mean diameter data. Differential scanning calorimetry determined the melting points of the constituents of the nanostructured lipid carriers. The antimicrobial activity of copper(II) complexloaded F5 against M. tuberculosis H37Rv showed better anti-tuberculosis activity than the free complexes. In vivo biological assays of complex-loaded F5 demonstrated reduced toxicity. Our results suggest that nanostructured lipid carriers could be a potential nanotechnological strategy to optimise tuberculosis treatment.


Subject(s)
Anti-Bacterial Agents/pharmacology , Castor Oil/pharmacology , Copper/pharmacology , Drug Carriers/pharmacology , Mycobacterium tuberculosis/drug effects , Biological Assay , Lipids , Microbial Sensitivity Tests , Nanostructures , Particle Size
4.
J Appl Microbiol ; 126(2): 580-594, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30466168

ABSTRACT

AIMS: The AGT1 gene encodes for a general α-glucoside-H+ symporter required for efficient maltotriose fermentation by Saccharomyces cerevisiae. In the present study, we analysed the involvement of four charged amino acid residues present in this transporter that are required for maltotriose consumption and fermentation by yeast cells. METHODS AND RESULTS: By using a knowledge-driven approach based on charge, conservation, location, three-dimensional (3D) structural modelling and molecular docking analysis, we identified four amino acid residues (Glu-120, Asp-123, Glu-167 and Arg-504) in the AGT1 permease that could mediate substrate binding and translocation. Mutant permeases were generated by site-directed mutagenesis of these charged residues, and expressed in a yeast strain lacking this permease (agt1∆). While mutating the Arg-504 or Glu-120 residues into alanine totally abolished (R504A mutant) or greatly reduced (E120A mutant) maltotriose consumption by yeast cells, as well as impaired the active transport of several other α-glucosides, in the case of the Asp-123 and Glu-167 amino acids, it was necessary to mutate both residues (D123G/E167A mutant) in order to impair maltotriose consumption and fermentation. CONCLUSIONS: Based on the results obtained with mutant proteins, molecular docking and the localization of amino acid residues, we propose a transport mechanism for the AGT1 permease. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results present new insights into the structural basis for active α-glucoside-H+ symport activity by yeast transporters, providing the molecular bases for improving the catalytic properties of this type of sugar transporters.


Subject(s)
Amino Acids/chemistry , Monosaccharide Transport Proteins/chemistry , Saccharomyces cerevisiae Proteins/chemistry , Symporters/chemistry , Trisaccharides/metabolism , Biological Transport, Active , Fermentation , Molecular Docking Simulation , Monosaccharide Transport Proteins/genetics , Monosaccharide Transport Proteins/metabolism , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Symporters/genetics , Symporters/metabolism
5.
Anim Reprod Sci ; 196: 59-68, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30149874

ABSTRACT

Objective was to investigate the effect of different progesterone (P4) concentrations during early follicular development on luteinizing hormone (LH) secretion and oocyte characteristics in beef cows. Primiparous cows (n = 24) were estrous pre-synchronized and follicular ablation was performed (d 0) 6 days following the time of ovulation. At the time of follicular ablation, cows were assigned to either: 1) high P4 treatment - HiP4; a new CIDR was inserted on d 0 to supplement P4 from the existing corpus luteum [CL], or 2) low P4 treatment - LoP4; a previously-used CIDR and two doses of PGF 8 to 12 h apart were given on d 0. Concentrations of P4 were greater (P < 0.01) in the cows of the HiP4 than LoP4 group on d 1.5, 2.5, and 3.5. Peripheral concentrations of E2 were greater (P < 0.05) in the cows of the LoP4 than HiP4 group on d 2.5 and 3.5. Frequency of LH pulses was greater (P <  0.05) in the LoP4 than HiP4 group on d 2.5, but mean LH concentration and pulse amplitude did not differ between treatments. Number of follicles aspirated per cow, total oocytes recovered, recovery rate, percentage of oocytes graded 1 to 3, oocyte diameter, percentage BCB+ oocytes, and relative abundance of oocyte mRNA for FST did not differ (P >  0.10) between treatments. In conclusion, lower P4 concentrations during early follicular development resulted in increased LH pulse frequency and E2 concentrations, but did not affect characteristics of oocyte developmental competence.


Subject(s)
Luteinizing Hormone/metabolism , Oocytes/cytology , Ovarian Follicle/cytology , Progesterone/pharmacology , Progestins/pharmacology , Animals , Cattle , Corpus Luteum/cytology , Corpus Luteum/drug effects , Corpus Luteum/physiology , Estrus Synchronization , Female , Luteinizing Hormone/drug effects , Oocytes/drug effects , Oocytes/physiology , Ovarian Follicle/drug effects , Ovarian Follicle/physiology , Ovulation
6.
Anim Reprod Sci ; 196: 69-76, 2018 Sep.
Article in English | MEDLINE | ID: mdl-29950280

ABSTRACT

Two experiments were conducted to investigate the role of relatively lesser and greater progesterone (P4) concentrations during early follicular development on ovulatory follicle growth and pregnancy rate in beef cattle. In Experiment 1, time of ovulation was synchronized with the 5 d CO-Synch + CIDR (Controlled Internal Drug Release) program in multiparous cows (n = 241). Six days after the 2nd GnRH injection of the pre-synchronization program (d 0), ablation of follicles ≥ 5 mm in the ovaries was performed and cows were assigned to receive either a previously used CIDR and 2x-25 mg PGF2α doses 8 h apart (LoP4), or a new CIDR (HiP4). On d 5, CIDR were removed from all cows, 2x-25 mg PGF2α were administered, and estrous detection tail paint was applied. Timed artificial insemination (TAI) was performed on d 8. On d 5, P4 concentrations were greater (P <  0.01) in the HiP4 (4.9 ± 0.13 ng/mL) than LoP4 (1.0 ± 0.06 ng/mL) treatment group. Conversely, d 5 estradiol (E2) concentrations and follicular diameter were greater (P <  0.01) in the LoP4 (5.0 ± 0.23 pg/mL and 8.9 ± 0.20 mm) than HiP4 (1.5 ± 0.12 pg/mL and 7.4 ± 0.15 mm) treatment group. Follicular diameter at TAI (12.0 ± 0.12 mm, Table 1) and TAI pregnancy rate did not differ (P >  0.10) between treatment groups. In Experiment 2, a new follicular wave was induced with estradiol benzoate on d -7, and cows (n = 275) were assigned on d 0 to receive 25 mg PGF2α and either have the CIDR replaced with a new CIDR (HiP4) or the used CIDR was left in place (LoP4).Furthermore, all cows received GnRH on d 0. The CIDRs were removed from all cows on d 5 and two doses of -25 mg PGF2α were administered. Estrous detection combined with AI 12 h later (Estrus-AI) was performed for 60 h after CIDR removal with TAI coupled with GnRH administration at 72 h if estrus was not detected. The concentrations of P4 on d 5 were greater (P <  0.01) in the HiP4 (2.8 ± 0.10 ng/ml) than LoP4 (1.7 ± 0.05 ng/mL) treatment group. For cows that were detected in estrus after PGF2α administration, estrous response (83.5%) and interval to estrus (55.0 ± 0.5 h) did not differ between treatment groups. Pregnancy rate (combined Estrus-AI and TAI) that resulted from breeding at the time of the synchronized time of estrus was similar between treatment groups (HiP4: 77.1%; LoP4: 82.3%). In conclusion, differences in P4 concentrations during early follicular development do not effect pregnancy rate in beef cows when the cows are inseminated at the time of a synchronized estrus if the cows have similar intervals of proestrus.


Subject(s)
Cattle/physiology , Estrus Synchronization/physiology , Pregnancy Rate , Progesterone/physiology , Animals , Dinoprost , Female , Gonadotropin-Releasing Hormone , Insemination, Artificial , Pregnancy , Progesterone/blood
7.
Phys Rev E ; 96(6-1): 062143, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29347279

ABSTRACT

What are the necessary ingredients for log-periodicity to appear in the dynamics of a random walk model? Can they be subtle enough to be overlooked? Previous studies suggest that long-range damaged memory and negative feedback together are necessary conditions for the emergence of log-periodic oscillations. The role of negative feedback would then be crucial, forcing the system to change direction. In this paper we show that small-amplitude log-periodic oscillations can emerge when the system is driven by positive feedback. Due to their very small amplitude, these oscillations can easily be mistaken for numerical finite-size effects. The models we use consist of discrete-time random walks with strong memory correlations where the decision process is taken from memory profiles based either on a binomial distribution or on a delta distribution. Anomalous superdiffusive behavior and log-periodic modulations are shown to arise in the large time limit for convenient choices of the models parameters.

8.
Pharmazie ; 72(12): 721-727, 2017 Dec 01.
Article in English | MEDLINE | ID: mdl-29441956

ABSTRACT

Curcumin (CUM) possesses therapeutic activity against diverse skin disorders (SD); however, its clinical use faces many challenges related to physicochemical and bioavailability characteristics, that can be solve designing a new drug delivery system for CUM to treat SD. Cationic solid lipid nanoparticles (CSLN) were developed and physicochemically analyzed. The ingredients and methods adopted in this study promoted the successful preparation of CSLN with a monodispersed particle size of 218.4-238.6 nm and a polydispersity index of 0.156-0.350. A differential scanning calorimetric assay demonstrated that CUM was incorporated. The atomic force microscopy images showed uniform spherical particles, and light scattering technique confirmed the size of the particles. The zeta potential of the CSLN was +23.1 to +30.1 mV, which is important in targeting the drug to the diseased tissue that presents unregulated apoptosis. All formulations behaved as controlled drug delivery systems of CUM, as demonstrated by an in vitro drug release study, which delayed the start of drug release from formulations. At the end of the experiment, the formulations had released 14.74-21.23% of the incorporated CUM. In conclusion, the results suggest the potential of this CSLN as a controlled CUM delivery system for the treatment of SD.


Subject(s)
Curcumin/administration & dosage , Dermatologic Agents/administration & dosage , Drug Delivery Systems , Nanoparticles , Calorimetry, Differential Scanning , Cations , Chemistry, Pharmaceutical/methods , Curcumin/chemistry , Delayed-Action Preparations , Dermatologic Agents/chemistry , Drug Carriers/chemistry , Drug Liberation , Lipids/chemistry , Microscopy, Atomic Force , Particle Size , Skin Diseases/drug therapy
9.
J Oral Rehabil ; 43(11): 824-832, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27545052

ABSTRACT

The study investigated whether chronic TMD patients with disc displacement with reduction (DDR), performing non-assisted maximum jaw movements, presented any changes in their mandibular kinematics with respect to an age-matched control group. Moreover, it was examined whether jaw kinematics and a valid clinic measure of oro-facial functional status have significant associations. Maximum mouth opening, mandible protrusion and bilateral laterotrusions were performed by 20 patients (18 women, 2 men; age, 18-34 years) and 20 healthy controls (17 women, 3 men; age, 20-31 years). The three-dimensional coordinates of their mandibular interincisor and condylar reference points were recorded by means of an optoelectronic motion analyser and were used to quantitatively assess their range of motion, velocity, symmetry and synchrony. Three functional indices (opening-closing, mandibular rototranslation, laterotrusion - right and left - and protrusion) were devised to summarise subject's overall performance, and their correlation with the outcome of a clinical protocol, the oro-facial myofunctional evaluation with scores (OMES), was investigated. TMD patients were able to reach maximum excursions of jaw movements comparable to healthy subjects' performances. However, their opening and closing mandibular movements were characterised by remarkable asynchrony of condylar translation. They had also reduced jaw closing velocity and asymmetric laterotrusions. The functional indices proved to well summarise the global condition of jaw kinematics, highlighting the presence of alterations in TMD-DDR patients, and were linearly correlated with the oro-facial functional status. The jaw kinematic alterations seem to reflect both oro-facial motor behaviour adaptation and a DDR-related articular impairment.


Subject(s)
Imaging, Three-Dimensional , Mandibular Condyle/physiopathology , Temporomandibular Joint Disorders/physiopathology , Temporomandibular Joint/physiopathology , Adolescent , Adult , Biomechanical Phenomena , Female , Humans , Male , Mandibular Condyle/diagnostic imaging , Radiography , Range of Motion, Articular , Temporomandibular Joint/diagnostic imaging , Temporomandibular Joint Disorders/diagnostic imaging , Young Adult
10.
Phys Rev E ; 93(5): 052116, 2016 05.
Article in English | MEDLINE | ID: mdl-27300839

ABSTRACT

We develop an approach for performing scaling analysis of N-step random walks (RWs). The mean square end-to-end distance, 〈R[over ⃗]_{N}^{2}〉, is written in terms of inner persistence lengths (IPLs), which we define by the ensemble averages of dot products between the walker's position and displacement vectors, at the jth step. For RW models statistically invariant under orthogonal transformations, we analytically introduce a relation between 〈R[over ⃗]_{N}^{2}〉 and the persistence length, λ_{N}, which is defined as the mean end-to-end vector projection in the first step direction. For self-avoiding walks (SAWs) on 2D and 3D lattices we introduce a series expansion for λ_{N}, and by Monte Carlo simulations we find that λ_{∞} is equal to a constant; the scaling corrections for λ_{N} can be second- and higher-order corrections to scaling for 〈R[over ⃗]_{N}^{2}〉. Building SAWs with typically 100 steps, we estimate the exponents ν_{0} and Δ_{1} from the IPL behavior as function of j. The obtained results are in excellent agreement with those in the literature. This shows that only an ensemble of paths with the same length is sufficient for determining the scaling behavior of 〈R[over ⃗]_{N}^{2}〉, being that the whole information needed is contained in the inner part of the paths.

11.
Carbohydr Polym ; 148: 371-9, 2016 09 05.
Article in English | MEDLINE | ID: mdl-27185151

ABSTRACT

Morphology and different structural features of V-amylose complexes prepared with different concentrations (1%, 2%, 3%) of glycerol monostearate (GMS) and normal maize (NMS), waxy maize (WMS), and high amylose maize (HAMS) starches were evaluated using X-ray diffraction, differential scanning calorimetry, scanning electronic microscopy (SEM), atomic force microscopy (AFM), and transmission electronic microscopy (TEM). There was inclusion complex formation between all starches and GMS regardless of emulsifier concentration, with exception of WMS-2%GMS and WMS-3%GMS samples. All of the inclusion complexes displayed a V-type crystalline pattern and endothermic dissociation peaks between 115 and 120°C. They also displayed faceted crystalline structures with a tendency of the crystals to aggregate and form agglomerates of various sizes. TEM images of the complexes showed an aggregated strand structure interwoven with the GMS. Emulsifier and amylose quantities directly influenced complex formation. At high GMS concentrations, there was higher tendency of emulsifier to self-associate rather than form complexes with amylose.


Subject(s)
Amylose/chemistry , Glycerol/chemistry , Starch/chemistry , Amylose/metabolism , X-Ray Diffraction , Zea mays/chemistry
12.
Pflugers Arch ; 468(2): 229-41, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26490459

ABSTRACT

Complex regional pain syndrome type 1 (CRPS1) may be evoked by ischemia/reperfusion, eliciting acute and chronic pain that is difficult to treat. Despite this, the underlying mechanism of CRPS1 has not been fully elucidated. Therefore, the goal of this study is to evaluate the involvement of inflammation, oxidative stress, and the transient receptor potential ankyrin 1 (TRPA1) channel, a chemosensor of inflammation and oxidative substances, in an animal model of chronic post-ischemia pain (CPIP). Male Wistar rats were subjected to 3 h hind paw ischemia/reperfusion (CPIP model). Different parameters of nociception, inflammation, ischemia, and oxidative stress were evaluated at 1 (acute) and 14 (chronic) days after CPIP. The effect of a TRPA1 antagonist and the TRPA1 immunoreactivity were also observed after CPIP. In the CPIP acute phase, we observed mechanical and cold allodynia; increased levels of tumor necrosis factor-α (hind paw), ischemia-modified albumin (IMA) (serum), protein carbonyl (hind paw and spinal cord), lactate (serum), and 4-hydroxy-2-nonenal (4-HNE, hind paw and spinal cord); and higher myeloperoxidase (MPO) and N-acetyl-ß-D-glucosaminidase (NAGase) activities (hind paw). In the CPIP chronic phase, we detected mechanical and cold allodynia and increased levels of IMA (serum), protein carbonyl (hind paw and spinal cord), and 4-HNE (hind paw and spinal cord). TRPA1 antagonism reduced mechanical and cold allodynia 1 and 14 days after CPIP, but no change in TRPA1 immunoreactivity was observed. Different mechanisms underlie acute (inflammation and oxidative stress) and chronic (oxidative stress) phases of CPIP. TRPA1 activation may be relevant for CRPS1/CPIP-induced acute and chronic pain.


Subject(s)
Acute Pain/metabolism , Chronic Pain/metabolism , Hindlimb/blood supply , Nociception , Reflex Sympathetic Dystrophy/metabolism , TRPC Cation Channels/antagonists & inhibitors , Acetylglucosaminidase/metabolism , Acute Pain/etiology , Aldehydes/metabolism , Animals , Chronic Pain/etiology , Cold Temperature , Hyperalgesia/etiology , Hyperalgesia/metabolism , Lactic Acid/blood , Male , Oxidative Stress , Peroxidase/metabolism , Protein Carbonylation , Rats , Rats, Wistar , Reflex Sympathetic Dystrophy/etiology , Reperfusion Injury/complications , Serum Albumin/metabolism , TRPA1 Cation Channel , TRPC Cation Channels/metabolism , Tumor Necrosis Factor-alpha/blood
13.
J Theor Biol ; 387: 181-8, 2015 Dec 21.
Article in English | MEDLINE | ID: mdl-26471071

ABSTRACT

In this work, we used five cell lineages, cultivated in vitro, to show they follow a common functional form to the growth rate: a sigmoidal curve, suggesting that competition and cooperation (usual mechanisms for systems with this behavior) might be present. Both theoretical and experimental investigations, on the causes of this behavior, are challenging for the research field; since the sigmoidal form to the growth rate seems to absorb important properties of such systems, e.g., cell deformation and statistical interactions. We shed some light on this subject by showing how cell spreading affects the radius behavior of the growing colonies. Doing numerical time derivatives of the experimental data, we obtained the growth rates. Using reduced variables for the time and rates, we obtained the collapse of all colonies growth rates onto one curve with sigmoidal shape. This suggests a universal-type behavior, with regime transition related to a morphological transition of adherent cell colonies.


Subject(s)
Models, Biological , Animals , Cell Adhesion , Cell Line, Tumor , Cell Shape , Humans , Mice , Time Factors
15.
Transplant Proc ; 47(2): 511-6, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25769599

ABSTRACT

INTRODUCTION: Early lymphocyte recovery after allogeneic hematopoietic stem cell transplantation (HSCT) is related to the prevention of serious infections and the clearing of residual tumor cells. METHODS: We analyzed the absolute lymphocyte count at 20 (D+20) and 30 (D+30) days after HSCT in 100 patients with malignant hematologic diseases and correlated with the risk of transplant-related mortality, overall survival (OS), disease-free survival (DFS), nonrelapsed mortality (NRM), and risk of infection. RESULTS: Patients presenting with lymphocyte counts of <300 × 103/µL on D+30 have a 3.76 times greater risk of death in <100 days. Over a medium follow-up of 20 months OS, DFS, and NRM were similar between the groups. CONCLUSION: In our group of patients delayed lymphocyte recovery after HSCT was a predictor of early death post-HSCT.


Subject(s)
Hematopoietic Stem Cell Transplantation , Leukemia/blood , Leukemia/therapy , Lymphocyte Count , Myelodysplastic Syndromes/blood , Myelodysplastic Syndromes/therapy , Adolescent , Adult , Aged , Disease-Free Survival , Female , Humans , Leukemia/mortality , Male , Middle Aged , Myelodysplastic Syndromes/mortality , Predictive Value of Tests , Retrospective Studies , Survival Rate , Time Factors , Transplantation, Homologous , Treatment Outcome , Young Adult
16.
Article in English | MEDLINE | ID: mdl-25353742

ABSTRACT

We study a one-dimensional discrete-time non-Markovian random walk with strong memory correlations subjected to pauses. Unlike the Scher-Montroll continuous-time random walk, which can be made Markovian by defining an operational time equal to the random-walk step number, the model we study keeps a record of the entire history of the walk. This new model is closely related to the one proposed recently by Kumar, Harbola, and Lindenberg [Phys. Rev. E 82, 021101 (2010)], with the difference that in our model the stochastic dynamics does not stop even in the extreme limit of subdiffusion. Surprisingly, this small difference leads to large consequences. The main results we report here are exact results showing ultraslow diffusion and a stationary diffusion regime (i.e., localization). Specifically, the equations of motion are solved analytically for the first two moments, allowing the determination of the Hurst exponent. Several anomalous diffusion regimes are apparent, ranging from superdiffusion to subdiffusion, as well as ultraslow and stationary regimes. We present the complete phase diffusion diagram, along with a study of the persistence and the statistics in the regions of interest.


Subject(s)
Diffusion , Markov Chains , Models, Biological , Models, Chemical , Models, Statistical , Rheology/methods , Computer Simulation
17.
Anim Reprod Sci ; 145(1-2): 15-22, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24461792

ABSTRACT

The objectives of the study were to assess: (1) preovulatory serum LH concentrations and (2) synchrony of ovulation after im or iu administration of GnRH with or without the addition of glycerol. Cows were presynchronized with 2 injections of PGF2α given 14d apart (starting at 26±3DIM) followed by Ovsynch (OV; GnRH-7d-PGF2α-48h-GnRH) 12d later. At the time of the second GnRH of OV (GnRH2), cows were blocked by parity and randomly allocated to 1 of 4 treatments: (1) control (CON; n=8) received 2mL of sterile water im; (2) im (IM; n=8) received 100µg of GnRH im; (3) cows were infused with 200µg GnRH into the uterus (IU; n=9); and (4) iu administration of 200µg GnRH plus glycerol 7% v/v (IUG; n=8). Serum circulating progesterone concentrations at hour 0 did not differ (P>0.05) among groups. Concentrations of LH were greater (P<0.05) in IM than IU, IUG, and CON cows at hours 1, 1.5, 2, and 3. All cows ovulated within 48h in the IM (8/8) group followed by IU (6/9) and IUG (4/8) groups, and only two out of eight cows ovulated in the CON group. Although iu administration of GnRH in the IU and IUG groups resulted in lower serum concentrations of LH than IM cows, IU or IUG cows were able to ovulate within 48h after GnRH2 administration.


Subject(s)
Cattle , Estrus Synchronization/methods , Glycerol/administration & dosage , Gonadotropin-Releasing Hormone/administration & dosage , Lactation , Luteinizing Hormone/blood , Animals , Cattle/blood , Dairying , Drug Administration Routes , Female , Lactation/blood , Ovulation/drug effects , Ovulation Induction/methods , Ovulation Induction/veterinary , Progesterone/blood , Uterus
18.
J Nanosci Nanotechnol ; 14(9): 6614-23, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25924307

ABSTRACT

Iron oxide nanostructured (ION) electrodes were assembled layer-by-layer onto ITO-coated glass substrates and their structure, morphology, and electrochemical properties were investigated, the latter aiming at the development of a chemical sensor for Cu2+. The electrodes were built by immersing the substrate alternately into an aqueous colloidal suspension of positively charged magnetite nanoparticles (np-Fe3O4, 8 nm) and an aqueous solution of anionic sodium sulfonated polystyrene (PSS). The adsorbed amount of both materials was monitored ex-situ by UV-vis spectroscopy and it was found to increase linearly with the number of deposition cycles. The resulting films feature a densely-packed structure of magnetite nanoparticles, as suggested by AFM and Raman spectroscopy, respectively. Cyclic voltammograms of electrodes immersed in acetate buffer (pH 4.6) displayed three electrochemical events that were tentatively ascribed to the reduction of Fe(III) oxy-hydroxide to magnetite, reduction of maghemite to magnetite, and finally oxidation of magnetite to maghemite. The effect of np-Fe3O4/PSS bilayers on the ION electrode performance was to increase the anodic and cathodic currents produced during electrochemical oxidation-reduction of the Fe(CN)(3-/4-) redox couple. With more bilayers, the ION electrode provided higher anodic/cathodic currents. Moreover, the redox couple exhibited a quasi-reversible behavior at the ION electrode as already observed with other working electrode systems. Fitting of voltammetry data provided the apparent electron transfer constants, which were found to be higher in ION electrodes for both redox couples (Fe(CN)(3-/4-) and Cu(2+/0)). By means of differential pulsed anodic stripping voltammetry, the ION electrodes were found to respond linearly to the presence of Cu2+ in aqueous samples in the range between 1.0 and 8.0 x 10(-6) mol x L(-1) and displayed a limit of detection of 0.3 x 10(-8) mol x L(-1). The sensitivity was - 0.6µA/µmol x L(-1). In standard addition and recovery experiments performed with tap water the recovery was about 102%-119%. In similar experiments conducted with ground and instant coffee samples the recovery was 92.5% and 103%, respectively. Furthermore, the ION electrodes were almost insensitive to the presence of common interfering ions, such as Zn2+, Mn2+, Ni2+, and Fe3+, even at concentrations ten times higher than that of Cu2+.


Subject(s)
Copper/analysis , Electrochemical Techniques/methods , Magnetite Nanoparticles/chemistry , Electrodes
19.
Article in English | MEDLINE | ID: mdl-24032783

ABSTRACT

For almost a decade the consensus has held that the random walk propagator for the elephant random walk (ERW) model is a Gaussian. Here we present strong numerical evidence that the propagator is, in general, non-Gaussian and, in fact, non-Lévy. Motivated by this surprising finding, we seek a second, non-Gaussian solution to the associated Fokker-Planck equation. We prove mathematically, by calculating the skewness, that the ERW Fokker-Planck equation has a non-Gaussian propagator for the superdiffusive regime. Finally, we discuss some unusual aspects of the propagator in the context of higher order terms needed in the Fokker-Planck equation.

20.
Minerva Stomatol ; 62(7-8): 289-94, 2013.
Article in English | MEDLINE | ID: mdl-24002565

ABSTRACT

AIM: This study assessed the effect of fermented milk on the enamel of primary teeth in the presence and absence of fluoride. METHODS: Sixty enamel blocks (4X4 mm) underwent surface microhardness analysis (Knoop). The blocks were randomly distributed into 5 groups of 12 samples in each group according to the following treatments: Group 1) pH cycling and fermented milk (control); Group 2) pH cycling and dentifrice; Group 3) pH cycling and fermented milk and dentifrices; Group 4) varnish and pH cycling and fermented milk; Group 5) varnish and pH cycling and fermented milk and dentifrice. After the treatments, new microhardness determination was carried out and the surface microhardness change ratio was calculated (%SMH). The data were submitted to the Shapiro-Wilk normality test, ANOVA test, Tukey's test and paired t-test (P<0.05). RESULTS: It was observed that after treatment, all groups showed statistically significant reduction (P<0.05) for initial surface microhardness. Group 1 showed the lowest microhardness (73.01±9.68 KNH) compared to groups 2, 3 and 4. Group 5 (172.5±45.89KNH) showed a greater surface microhardness than Group 4 (122.0±22.33 KNH). CONCLUSION: It was concluded that the fermented milk adversely altered the microhardness of the samples and that fluorine contributes to a smaller reduction in the microhardness change ratio (SMH%). The combined solution of toothpaste with fluoride varnish provided a lower surface microhardness reduction of the samples.


Subject(s)
Cariostatic Agents/pharmacology , Cultured Milk Products/adverse effects , Dental Enamel/drug effects , Fluorides, Topical/pharmacology , Sodium Fluoride/pharmacology , Acids/adverse effects , Animals , Cariostatic Agents/administration & dosage , Cultured Milk Products/chemistry , Fermentation , Fluorides, Topical/administration & dosage , Hardness Tests , Humans , Hydrogen-Ion Concentration , In Vitro Techniques , Molar/drug effects , Random Allocation , Sodium Fluoride/administration & dosage , Tooth Erosion/etiology , Tooth Erosion/prevention & control , Tooth, Deciduous
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