Imbibition in Disordered Media

The physics of liquids in porous media gives rise to many interesting phenomena, including imbibition where a viscous fluid displaces a less viscous one. Here we discuss the theoretical and experimental progress made in recent years in this field. The emphasis is on an interfacial description, akin to the focus of a statistical physics approach. Coarse-grained equations of motion have been recently presented in the literature. These contain terms that take into account the pertinent features of imbibition: non-locality and the quenched noise that arises from the random environment, fluctuations of the fluid flow and capillary forces. The theoretical progress has highlighted the presence of intrinsic length-scales that invalidate scale invariance often assumed to be present in kinetic roughening processes such as that of a two-phase boundary in liquid penetration. Another important fact is that the macroscopic fluid flow, the kinetic roughening properties, and the effective noise in the problem are all coupled. Many possible deviations from simple scaling behaviour exist, and we outline the experimental evidence. Finally, prospects for further work, both theoretical and experimental, are discussed.Comment: Review article, to appear in Advances in Physics, 53 pages LaTe

Incidence and antimicrobial susceptibilities of genital mycoplasmas in outpatient women with clinical vaginitis in Athens, Greece

Objectives: The incidence and antimicrobial susceptibilities of Ureaplasma urealyticum and Mycoplasma hominis, isolated from vaginal and endocervical swabs collected from 369 outpatient women, were determined. Methods: Isolation, identification and typing of the pathogens were performed by means of conventional methods. The antimicrobial susceptibilities of the genital mycoplasmas were determined with commercially available kits and evaluated according to the CLSI. Results and conclusions: In 65 (47.44%) out of the 137 positive specimens, U. urealyticum was grown as a single pathogen, in 0.72% M. hominis was grown as a single pathogen and in 2.92% both urogenital mycoplasmas were grown. In the remaining specimens (48.90%), there was a mixed growth with other microbes. Of the isolated U. urealyticum strains, 87.4% and 98.2% were susceptible to tetracycline and doxycycline, respectively, 79.2% were susceptible to josamycin, 48.6% were susceptible to clarithromycin and 91.8% were susceptible to pristinamycin, while erythromycin, azithromycin, ciprofloxacin and ofloxacin proved to be inactive against most of the strains. M. hominis isolates were 100% susceptible to tetracycline, doxycycline and pristinamycin, while susceptibilities to the other antimicrobial agents varied mainly in the range of 'intermediate' or 'resistant'. As results originating from similar studies from various countries are very controversial, the simplest way to avoid therapeutic failures would be the implementation of rational treatment regimens based on culture isolation and the in vitro determination of the antimicrobial susceptibility of genital mycoplasmas in each clinical case

The effect of orthodontic adhesive and bracket-base design in adhesive remnant index on enamel

Background: The purpose of this study was to identify the effects of bracket-base design and adhesive on adhesive remnant index (ARI) and enamel surface area covered by adhesive. Methods: The sample consisted of 32 recently extracted premolars. The teeth were randomly assigned to one of four groups: conventional mesh base and composite resin; laser-etched base and composite resin; conventional mesh base and resin-modified glass ionomer; and laser-etched base and resin-modified glass ionomer. After a week, all brackets were debonded. The debonded bracket-base surface and the buccal surface of each tooth were studied under the microscope, and the remaining adhesive was scored using the ARI. The extent of coverage of the tooth by adhesive remnants was also calculated, outlining the different areas of adhesive. Results: A Fisher's exact test indicated significant differences between the groups. The adhesive resin group showed the highest ARI scores independent of the bracket-base design, whereas between the two bracket-base designs, the laser-etched bracket design showed higher ARI. ARI scores reliably depict the extent of enamel covered by adhesive compared with the measurement of the actual area covered. Conclusion: Varying the bracket base and adhesive may result in different ARI scores, which can affect the enamel surface during debonding. © 2015 World Federation of Orthodontists

Serum endocan levels in patients with chronic obstructive pulmonary disease: A potential role in the evaluation of susceptibility to exacerbation

[No abstract available

Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy

Purpose: Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy. Methods: The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights. Results: The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months. Conclusions: Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS. © 2020, Springer Nature Switzerland AG

Serum vitamin D levels in patients with obstructive sleep apnea syndrome and level changes after continuous positive airway pressure therapy

Purpose: Patients with obstructive sleep apnea syndrome (OSAS) have been found to exhibit lower serum vitamin D levels, even when the control groups are matched for confounding conditions. However, contradictory studies are also present. This study aimed to compare serum 25-hydroxyvitamin D (25(OH)D) levels between adult patients with OSAS and non-apneic controls and to evaluate the changes in 25(OH)D levels after 3 and 12 months of continuous positive airway pressure (CPAP) therapy. Methods: The study was comprised of 30 patients with OSAS and 30 controls. Serum 25(OH)D levels were determined at baseline and after 3 and 12 months of CPAP therapy in all patients with OSAS. For analysis, patients with OSAS were divided into subgroups by adherence, with adherence defined as CPAP usage for > 4 h per night on at least 70% of nights. Results: The 25(OH)D levels were not significantly different between OSAS and control groups at baseline. 25(OH)D levels did not change after 3 and 12 months of CPAP therapy. Patients who were CPAP-adherent showed less reduction in 25(OH)D levels compared with non-adherent ones (21.18 ± 9.3 vs. 12.13 ± 3.8 ng/mL, p = 0.022) after 1 year. The 25(OH)D levels were significantly correlated with higher daily CPAP usage at 3 and 12 months. Mean daily CPAP usage was a significant predictor of serum 25(OH)D levels at 12 months. Conclusions: Patients with OSAS who demonstrated good CPAP adherence showed significantly higher 25(OH)D levels after 1 year compared with those not adequately using CPAP. Long-term good CPAP adherence and highly daily CPAP usage positively affected 25(OH)D levels in patients with OSAS. © 2020, Springer Nature Switzerland AG

Upscaling of stochastic micro model for suspension transport in porous media

© Springer The definitive version can be found at www.springerlink.comMicro scale population balance equations of suspension transport in porous media with several particle capture mechanisms are derived, taking into account the particle capture by accessible pores, that were cut off the flux due to pore plugging. The main purpose of the article is to prove that the micro scale equations allow for exact upscaling (averaging) in case of filtration of mono dispersed suspensions. The averaged upper scale equations generalise the classical deep bed filtration model and its latter modifications.P. Bedrikovetsk