Correction: Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4.

Correction for 'Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4' by Andreu Andrio et al., Phys. Chem. Chem. Phys., 2019, 21, 12948-12960, DOI: 10.1039/C8CP07472K.

Temperature dependence of anomalous protonic and superprotonic transport properties in mixed salts based on CsH2PO4.

We present an experimental study and a theoretical interpretation of the temperature dependence of the transport properties of doped CsH2PO4 salts in both protonic and superprotonic phases. Cesium phosphate based solid electrolytes are technologically relevant because their operational temperature range is about 100 to 300 °C in which a superprotonic transition may manifest depending on its mixed composition. The experimental study was carried out using impedance spectroscopy at the temperature range of 150-230 °C, and the protonic and superprotonic transport properties and proton concentrations were calculated and analyzed by using the electrode polarization, and the Debye and Cole-Cole models for the dielectric constant. We have shown that the transport properties predicted by the Cole-Cole model are consistent with the conductivity measurements whereas the Debye model shows some inconsistencies. We attribute this to the fact that the Cole-Cole model incorporates the effects of interactions among charge carriers better than the more commonly used Debye model. In this way, our work shows a more consistent approach to determine the transport properties of solid electrolytes and, therefore, provides a more reliable tool to analyze the transport properties of heterogeneous solid electrolytes that can be used in electrochemical devices, including fuel cells and supercapacitors.

Analysis of the application of the generalized monod kinetics model to describe the human corneal oxygen-consumption rate during soft contact lens wear.

This work is an analysis of the application of the generalized Monod kinetics model describing human corneal oxygen consumption during soft contact lens wear to models previously used by Chhabra et al. (J Biomed Mater Res B Appl Biomater, 2009a;90:202-209, Optom Vis Sci 2009b;86:454-466) and Larrea and Büchler (Invest Ophthalmol Vis Sci 2009;50:1076-1080). We use oxygen tension from in vivo estimations provided by Bonanno [Bonanno et al., Invest Ophthalmol Vis Sci 2002;43:371-376, and Bonanno et al 2009]. We consider four hydrogel and six silicone hydrogel lenses. The cornea is considered a single homogeneous layer, with constant oxygen permeability regardless of the type of lens worn. Our calculations yield different values for the maximum oxygen consumption rate Qc,max , whith differents oxygen tensions (high and low pc ) at the cornea-tears interface. Surprisingly, for both models, we observe an increase in oxygen consumption near an oxygen tension of 105 mmHg until a maximum is reached, then decreasing for higher levels of oxygen pressure. That is, when lowering the pressure of oxygen, the parameter Qc,max initially increases depending on the intensity of the change in pressure. Which, it could be related with the variation of the pH. Furthermore, it is also noted that to greater reductions in pressure, this parameter decreases, possibly due to changes in the concentration of glucose related to the anaerobic respiration. The averaged in vivo human corneal oxygen consumption rate of 1.47 × 10-4 cm3 of O2 /cm3 tissue s, with Monod kinetics model, considering all the lenses studied, is smaller than the average oxygen consumption rate value obtained using the Larrea and Büchler model. The impact that these calculations have on the oxygen partial pressure available at different depths in the corneal tissue is presented and discussed, taking into consideration previous models used in this study. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2269-2281, 2017.

Interconversion algorithm between mechanical and dielectric relaxation measurements for acetate of cis- and trans-2-phenyl-5-hydroxymethyl-1,3-dioxane.

The dielectric and mechanical spectroscopies of acetate of cis- and trans-2-phenyl-5-hydroxymethyl-1,3-dioxane are reported in the frequency domain from 10(-2) to 10(6)Hz. This ester has been selected in this study for its predominant α relaxation with regard to the ß relaxation, which can be neglected. This study consists of determining an interconversion algorithm between dielectric and mechanical measurements, given by using a relation between rotational and translational complex viscosities. These important viscosities were obtained from measures of the dielectric complex permittivity and by dynamic mechanical analysis, respectively. The definitions of rotational and translational viscosities were evaluated by means of fractional calculus, by using the fit parameters of the Havriliak-Negami empirical model obtained in the dielectric and mechanical characterization of the α relaxation. This interconversion algorithm is a generalization of the break of the Stokes-Einstein-Debye relationship. It uses a power law with an exponent defined as the shape factor, which modifies the translational viscosity. Two others factors are introduced for the interconversion, a shift factor, which displaces the translational viscosity in the frequency domain, and a scale factor, which makes equal values of the two viscosities. In this paper, the shape factor has been identified as the relation between the slopes of the moduli of the complex viscosities at higher frequency. This is interpreted as the degree of kinetic coupling between the molecular rotation and translational movements. Alternatively, another interconversion algorithm has been expressed by means of dielectric and mechanical moduli.

Host preference of the arbovirus vector Culex erraticus (Diptera: Culicidae) at Sonso Lake, Cauca Valley Department, Colombia.

Culex erraticus (Dyar & Knab) is a competent vector of Eastern equine encephalitis virus and subtype IC Venezuelan equine encephalitis virus, and both St. Louis encephalitis virus and West Nile virus have been isolated from field-collected specimens. Previous bloodmeal analysis studies have shown this species to be a generalist, feeding on a variety of mammals, birds, reptiles, and amphibians. This behavior can bridge arboviral transmission across different vertebrate groups. Our study examined the host preference of Cx. erraticus at Sonso Lake in Colombia. From July to August 2008, blood-engorged mosquitoes were collected from resting boxes, while vertebrate abundance was determined to calculate host preference. Based on mitochondrial DNA analysis of bloodmeals, birds were the predominant hosts (57.6%), followed by mammals (30.8%), and reptiles (6.7%); 9.5% of the bloodmeals were mixed. The most commonly fed upon species were: limpkin, black-crowned night-heron, striated heron, human, and capybara. Forage ratios showed the least bittern, limpkin, Cocoi heron, striated heron, capybara, and black-crowned night heron were preferred hosts across all vertebrates. Of the available avifauna, the least bittern, limpkin, striated heron, Cocoi heron, and black-crowned night heron were preferred, whereas the bare faced ibis, great egret, snowy egret, and cattle egret were under-used. This study shows that while Cx. erraticus is an opportunistic feeder, using diverse vertebrate hosts in the environment, certain avian species are targeted preferentially for bloodmeals.

Involvement of α2- and ß2-adrenoceptors on breast cancer cell proliferation and tumour growth regulation.

BACKGROUND AND PURPOSE: ß-Adrenoceptors are expressed in human and experimental animal breast cancer cells. However, the effect of the agonists and antagonists reported on cell proliferation and tumour growth was paradoxical, precluding their utilization as possible adjuvant therapy, mainly in the cases of refractory tumours. EXPERIMENTAL APPROACH: ß-Adrenoceptor expression was analysed by immunofluorescence and RT-PCR. Cell proliferation was assessed by [(3) H]-thymidine incorporation, tumour growth by measuring with a calliper and ERK 1/2 phosphorylation by Western blotting. KEY RESULTS: ß(2) -Adrenoceptor expression was confirmed in the mouse and human cells tested. Cell proliferation was increased by adrenaline (by α(2) -adrenoceptor action) and decreased in every tested cell line by the ß-adrenoceptor agonist isoprenaline and the ß(2) -adrenoceptor agonist salbutamol. Isoprenaline and salbutamol reduced tumour growth in every tumour tested (mouse C4-HD and CC4-3-HI and human IBH-4, IBH-6 and MDA-MB-231 cell lines growing as xenografts in nude mice). These effects were reversed by the ß-adrenoceptor antagonist propranolol. The α(2) -adrenoceptor antagonist rauwolscine and the ß(2) -adrenoceptor agonist salbutamol were equally effective in diminishing tumour growth. ERK 1/2 activation analysed in IBH-4 tumours correlated with tumour growth, with the ß-adrenoceptor agonists decreasing its activation. Inhibition of ERK 1/2 phosphorylation in vitro was mainly mediated by the PKA pathway. CONCLUSIONS AND IMPLICATIONS: In our experimental models, the ß-adrenoceptor agonists inhibited breast cancer cell proliferation and tumour growth, probably mediated by inhibition of ERK 1/2 phosphorylation. The ß-adrenoceptor agonists were as effective as the α(2) -adrenoceptor antagonist rauwolscine, providing possible novel adjuvant treatments for breast cancer.

Adrenoceptors: non conventional target for breast cancer?

Epinephrine and Norepinephrine, typically released during stress bind to nine different adrenoceptors (AR) which classically control the cardiovascular and respiratory systems. New targets were described for the many agonists and antagonists developed for these AR, as the central nervous system. During the last three decades, AR expression and action on the mammary gland/breast were extensively investigated. In the cow mammary gland, good milkability was associated with low density of beta(2)-AR and high density of alpha(2)-AR. In the rat normal mammary gland, beta-AR are expressed in the epithelial cells, alveoli, ducts, and adipocytes showing an exquisite regulation by steroid hormones and prolactin. In rat dimethylbenz(a)anthracene (DMBA) tumors, a close correlation was observed between tumor growth and beta-AR concentration. beta(2)-AR were described in numerous human cell lines and breast tumors. The action of beta-adrenergic compounds on cell proliferation is contradictory. While some authors found that beta-agonists significantly inhibit cancer cell proliferation and tumor growth in mice, others described a significant reduction in DNA synthesis by beta-blockers. Also, positive effects of beta-AR on human carcinoma cell migration have been described. alpha(2)-AR are expressed in human breast cancer and non-cancer cell lines, their stimulation being associated with increased cell proliferation. In vivo clonidine increased tumor growth and alpha (2)-adrenergic antagonists completely reversed this effect. When administered alone, rauwolscine inhibited tumor growth behaving as an inverse agonist. Therefore, the numerous adrenergic beta- and alpha-AR agonists or antagonists could prove to be unexpected therapeutic options for mammary gland/ breast and mainly breast cancer.

Alpha2-adrenoceptor action on cell proliferation and mammary tumour growth in mice.

BACKGROUND AND PURPOSE: Breast cancer, the most common cancer in women in most countries, is a highly stressful disease. Catecholamines released during stress bind to adrenoceptors and we have recently described alpha(2)-adrenoceptors in human breast cell lines, linked to enhanced cell proliferation. The purpose was to assess the in vivo effects of compounds acting on alpha(2)-adrenoceptors in a reliable model of breast cancer. EXPERIMENTAL APPROACH: The expression of alpha(2)-adrenoceptors was confirmed by immunocytochemistry, immunofluorescence and reverse transcription-PCR in the mouse mammary tumour cell line MC4-L5. Proliferation was assessed by [(3)H]thymidine incorporation and tumours were measured daily. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP digoxigenin nick-end labelling. KEY RESULTS: Incubation for 2 days with alpha(2)-adrenoceptor agonists (clonidine and dexmedetomidine) significantly enhanced proliferation of the mouse mammary tumour cell line MC4-L5. These agonists also significantly stimulated tumour growth of the progestin-dependent tumour C4-HD even in the presence of medroxyprogesterone acetate (MPA). In every tumour tested (C4-HD, CC4-2-HD and CC4-3-HI), regardless of MPA sensitivity, clonidine significantly enhanced tumour growth in the absence of MPA. The alpha(2)-adrenoceptor antagonists, yohimbine and rauwolscine, completely reversed the effects of clonidine. However, the group receiving yohimbine alone showed a nonsignificant but constant increase in tumour growth, whereas rauwolscine alone diminished tumour growth significantly, behaving as a reverse agonist. In CC4-3-HI tumours, rauwolscine treatment enhanced apoptosis and diminished the mitotic index, whereas clonidine had the inverse effect. CONCLUSIONS AND IMPLICATIONS: Alpha(2)-adrenoceptor agonists enhanced tumour growth and rauwolscine behaved in vivo as a reverse agonist, suggesting that it may be tested for adjuvant treatment.

Generalized hydrodynamics of a dilute suspension of finite-sized particles: dynamic viscosity.

We present a mesoscopic hydrodynamic description of the dynamics of colloidal suspensions. We consider the system as a gas of Brownian particles suspended in a Newtonian heat bath subjected to stationary nonequilibrium conditions imposed by a velocity field. By means of a generalized Fokker-Planck equation, we obtain a set of coupled differential equations for the local diffusion current and the evolution of the total stress tensor. We find that the dynamic shear viscosity of the system contains contributions arising from the finite size of the particles.

Interconversion of mechanical and dielectrical relaxation measurements for dicyclohexylmethyl-2-methyl succinate.

A comparison between results of dielectrical relaxation and dynamic mechanical spectroscopies is carried out for the alpha-relaxation of the ester dicyclohexyl methyl-2-methyl succinate (DCMMS). The results for the dielectric permittivity and the shear modulus measurements are presented according to the empirical Havriliak-Negami (HN) equation. By using the time-temperature principle a master curve in each case was obtained for several temperatures. The comparative analysis presented here is based on the assumption of a relationship between rotational and shear viscosities. The former one is associated to the dielectrical relaxation, whereas the latter is associated to mechanical relaxation. Both viscosities are not necessarily equal in general, and we assume that the difference between them is an important factor to appropriately compare the dielectrical and mechanical results.

Shear-induced shift of spinodal line in entangled polymer blends.

We study the shear-flow effects on phase separation of entangled polymer blends by incorporating into the chemical potential a nonequilibrium contribution due to the flow. The results are compared with those of a previous analysis by other authors which did not modify the chemical potential but used a different assumption for the stress tensor of the blend.

Legendre transform in the thermodynamics of flowing polymer solutions.

We propose a Legendre transform linking two different choices of nonequilibrium variables (viscous pressure tensor and configuration tensor) in the thermodynamics of flowing polymer solutions. This may avoid some current confusions in the analysis of thermodynamic effects in polymer solutions under flow.

Spontaneous apparent clinical resolution with histologic persistence of a case of extramammary Paget's disease: response to topical 5-fluorouracil.

An 86-year-old woman presented with a 3-year history of an erythematous axillary lesion, which was histologically confirmed to be extramammary Paget's disease (EMPD) confined to the epidermis and adnexa. Surprisingly, spontaneous clinical regression occurred in the lesion, but Paget's cells persisted within the epidermis and adnexa on histologic examination. One year of intermittent topical chemotherapy with 5-fluorouracil resulted in ulcers that were interpreted as EMPD and completely excised. Histologic examination showed a complete absence of Paget's cells. To our knowledge, only one previous report investigated apparent spontaneous clinical resolution with histologic persistence of EMPD. We emphasize that topical 5-fluorouracil cannot be considered a safe treatment modality for EMPD, but it may be useful in certain cases in which the extent of the lesions, or the general condition of the patient, advise against surgery or radiotherapy.

Widespread cutaneous necrosis and antiphospholipid antibodies: two episodes related to surgical manipulation and urinary tract infection.

Widespread cutaneous necrosis (WCN) associated with antiphospholipid antibodies is rare. Its mechanisms have yet to be elucidated, and there are no well-established guidelines for its management. We describe a woman who had two episodes of WCN related to surgical manipulation for urinary tract obstruction and urinary tract infection. Lupus anticoagulant was always positive. In the second episode anticardiolipin antibodies were elevated, and protein C levels were temporarily decreased. We found only ten previously reported cases of WCN associated with antiphospholipid antibodies, none of which were related to surgical manipulation.

Electrostatic forces as a possible mechanism underlying skeletal muscle contraction.

A possible mechanism is put forward to explain the sliding of thin filaments during muscle contraction. In our model, repulsion due to electrostatic forces is the mechanism which triggers crossbridges to cause the thin filaments to slide. The mechanism proposed could operate regardless of whether the myosin heads rotate or bend, although recent experimental evidence seems to confirm the latter action. In spite of its simplicity, the model prediction of the velocity of sliding of the thin filaments agrees well with experimental values from in vitro motility assays.

Immunohistochemical localization of very late activation integrins in healthy and diseased human gingiva.

The beta 1-integrins (VLA family) are cellular adhesion molecules (CAM) that play a major role in cell-cell and cell-matrix interactions. The expression pattern of CAM was studied in 5 clinically normal volunteers with healthy gingiva and in 18 patients with clinically different stages of periodontitis. In healthy human gingiva alpha 2, alpha 3 and alpha 6 integrin chains were found in a characteristic distribution, showing a broad continuous expression on the junctional and sulcular epithelium sites. The expression of these integrins was demonstrated primarily on the basal cell layers and in some cells of the stratum spinosum. Inflammatory stages of periodontitis revealed further upregulation of alpha 2, alpha 3 and alpha 6 integrins into the junctional and sulcular epithelial cells, which correlated with the stage of the periodontitis and the extent of the cellular infiltration. alpha 4 and alpha 6 were found to be the predominant beta 1 integrin chains on inflammatory cells. The amount of alpha 4 and alpha 6 positive infiltrative cells increased with the number of inflammatory cells. VCAM-1, the corresponding cell-cell ligand of VLA-4 (alpha 4) was present on the majority of subepithelial vessels in all stages of gingivitis and periodontitis. The alpha 5 subunit was expressed on both endothelium and gingival connective tissue cells. Samples from advanced periodontitis cases showed a higher number of alpha 5 positive mononuclear cells. In comparison to normal epidermis, human gingival epithelial cells express higher levels of integrins. This expression is further upregulated in advanced stages of periodontitis, indicating changes of the beta 1 integrin organization.

[Hospital infections in children in a general hospital]. / Infecciones hospitalarias en niños en un hospital general.

INTRODUCTION: The following is a summary of what was found after setting into motion an epidemiological surveillance system of nosocomial infections occurring in the Pediatrics Ward of a 2nd level general hospital. MATERIAL AND METHODS: The rate of interhospital infections was 7.6 episodes per 100 patients discharged; the most frequent infections were diarrheas (40.6%), urosepsis (14.3%) and pneumoniae (12.1%). The mortality rate was 0.33 deaths per 100 episodes. The average number of days spent in the hospital by the general population is 7.3 days and for infected patients, 24. The germs most frequently found were Klebsiella and E. coli. CONCLUSIONS: The control of nosocomial infections requires more efficient surveillance systems for all hospitals.

Deficiencia de los folatos en pacientes mayores de 60 anos. / Folic acid deficiency in patients with more than 60 years-old

Se estudiaron los niveles de folatos en l04 pacientes de la Consulta Externa y hospitalizados en el Servicio de Medicina del Hospital San Juan de Dios, encontrandose una deficiencia de folatos sericos en un 25.96% y niveles de folato intraeritrocitarios bajos en 22.12% de los pacientes. Llamo la atencion el porcentaje mayor de pacientes con folato serico bajos en la consulta externa, asi como un elevado numero de pacientes deficientes con hematocritos normales. (89.48%)

Statistical-mechanical theory of passive transport through partially sieving or leaky membranes.

The basic equations for multicomponent transport through partially sieving or leaky membranes are discussed from a statistical-mechanical viewpoint. They have the same mathematical form as the corresponding equations for open membranes, but differ in a discontinuous way from the equations for semipermeable membranes (since a "leak" in a semipermeable membrane constitutes a discontinuous or singular perturbation). Partially sieving membranes can be made to mimic semipermeable behavior through the introduction of characteristic time scales. They may approximate semipermeable behavior at short times, but always deviate at longer times.

Statistical-mechanical theory of passive transport through semipermeable membranes.

The first general multicomponent equations for transport through semipermeable membranes are derived from basic statistical-mechanical principles. The procedure follows that used earlier for open membranes, but semipermeability is modelled mathematically by the introduction of external forces on the impermeant species. Gases are treated first in order to clarify the problems involved, but the final results apply to general nonideal solutions of any concentration. The mixed-solvent effect is treated rigorously, and a mixed-solvent osmotic pressure is defined. A useful specific identification of so-called osmotic flow is given, along with a demonstration that such an identification cannot be unique. Results are obtained both for discontinuous membrane models, and for a continuous model.