Optical Pumping of TeH+: Implications for the Search for Varying mp/me

Molecular overtone transitions provide optical frequency transitions sensitive to variation in the proton-to-electron mass ratio ($\mu\equiv m_p/m_e$). However, robust molecular state preparation presents a challenge critical for achieving high precision. Here, we characterize infrared and optical-frequency broadband laser cooling schemes for TeH$^+$, a species with multiple electronic transitions amenable to sustained laser control. Using rate equations to simulate laser cooling population dynamics, we estimate the fractional sensitivity to $\mu$ attainable using TeH$^+$. We find that laser cooling of TeH$^+$ can lead to significant improvements on current $\mu$ variation limits

Relationship between biofilm formation and antibiotic resistance in commensal isolates of Staphylococcus epidermidis

Staphylococcus epidermidis is a common bacterial coloniser of the normal human microflora and usually have a benign relationship with the host. For several years, S. epidermidis was regarded as a harmless commensal microorganism. However, this bacterium is now recognised as an opportunistic pathogen, representing a leading cause of healthcare-associated infections. The major recognised determinants in the pathogenesis of S. epidermidis infections are its ability to form thick and multilayered biofilms along with high resistance to several classes of antibiotics. Biofilms are defined as structured communities of microorganisms embedded in a self-produced matrix of extracellular polymeric. It is well established that bacteria exhibiting a biofilm phenotype are more recalcitrant to antibiotic therapy. Hence, these two pathogenic features stated above appear to be intimately related. The present study aimed to evaluate the pathogenic potential of commensal S. epidermidis isolates through the assessment of their biofilm formation ability and antibiotic susceptibility profiles, as well as to analyse the relationship between biofilm formation and antibiotic resistance. To achieve that, thirty-one S. epidermidis isolates from Portuguese healthy volunteers (obtained from September 2012 to April 2013) were tested for biofilm formation ability, carriage of biofilm-associated genes (icaA, aap and bhp) and antibiotic susceptibility to six antibiotics (clindamycin, erythromycin, gentamicin, penicillin, rifampicin and vancomycin). The study of biofilm formation revealed that 20 (65%) isolates were able to produce biofilm at different levels, while 11 (35%) did not form biofilm. Moreover, 12 (39%) isolates were positive for icaA, 18 (58%) for aap, and 6 (19%) for bhp. With regards to the results of antibiotic susceptibility assays, the highest rates of resistance were detected for penicillin (n = 16, 52%), followed by erythromycin (n = 15, 48%) and gentamicin (n = 13, 42%), while the lowest rate was exhibited for ciprofloxacin (n = 2, 6%). All isolates were susceptible to rifampicin and vancomycin. By comparing the data on biofilm formation and antibiotic susceptibility assays, we found a significant higher frequency of antibiotic resistance in biofilm-formers than in non-biofilm formers (p = 0.02). Additionally, we also found a significant higher proportion of multidrug-resistant isolates among biofilm formers comparing with non-biofilm formers (p = 0.03), demonstrating a clear trend of isolates with biofilm formation ability to be resistant to two or more antibiotics simultaneously. In order to elucidate the nature of the relationship between biofilm formation and antibiotic resistance, we also compared the data on detection of biofilm-associated genes with the data on antibiotic susceptibility assays. In general, we also observed a tendency of isolates that carry the icaA and/or aap genes to be resistant to two or more antibiotics simultaneously. Interestingly, and when analysing the frequency of resistance for each of the antibiotics tested, the association between the presence of icaA gene and antibiotic resistance was particularly evident for gentamicin, with a p-value much close to the significance level (p = 0.07). Conversely, and with regards to aap gene, the same association was not observed. Overall, our findings provide evidence that commensal S. epidermidis strains are well equipped with biofilm formation determinants as well as are resistant to different groups of antibiotics. Moreover, our results support the existence of an association between biofilm formation and antibiotic resistance. Nevertheless, and taking into account other previously published results, our findings lead us to challenge the hypothesis that this association is common throughout all antibiotic classes. We rather hypothesise that this association might be restricted to some classes of antibiotics, especially aminoglycosides, and that it may be primarily associated with icaADBC operon and not with the biofilm phenotype per se

Plasma technology applied in textile industry

Plasma technology applied to textiles is a dry, environmentally and worker friendly method to achieve surface alteration without modifying the bulk properties of different materials. In particular, atmospheric non-thermal plasmas are appropriate because most textile materials are heat sensitive polymers and applicable in a continuous processes. In the last years plasma technology has become a very active, high growth research field, assuming a great importance among all available material surface modifications in textile industry. The main objective of this work is to present an update on the current state of art relating plasma technologies applied to textile industry. The main effects obtained by the application of plasma discharge and all the textile production chain such as: desizing, mercerization, dyeing, printing, composite and finishing will be superficially discussed

The effect of expansion ratio for creeping expansion flows of UCM fluids

A systematic numerical investigation on creeping flows in planar sudden expansions of viscoelastic fluids obeying the upper-convected Maxwell model is carried out to assess the combined effects of viscoelasticity, through the Deborah number, and expansion ratio (ER), which was varied between 1.25 and 32. At large expansion ratios (ER≥4) the flow becomes dominated by the downstream duct size and appropriately normalized quantities tend to be independent of ER. The recirculation size and strength become decreasing functions of De, whereas the Couette correction (the normalized entry pressure drop due to the presence of the expansion) increases. At small ER (ER≤3), however, no simple scaling laws are found and there is a complex interaction between De and ER leading to non-monotonic variations, with an initial decrease in the recirculation length at low Deborah numbers, followed by an enhancement as De increases

Plane sudden expansion flows of viscoelastic liquids

We report a systematic numerical investigation of the creeping flow of three different viscoelastic models, the UCM, Oldroyd-B and the linear form of the PTT model, through a 1:3 planar sudden expansion. Although the effect of elasticity is to reduce both the length and intensity of the recirculation region downstream of the expansion, we show that this reduction is much lower than previous studies have suggested and that, at high Deborah number, a significant region of recirculation still exists for all of the models studied

Functionalization of textile materials by double barrier discharge plasma

The pre-treatment of textile materials by non-thermal plasma technologies can offer many advantages over conventional chemical processes used to surface modification. This technology doesn’t involve the use of water and chemical reagents, resulting in a more eco-friendly and economical process. In this study air atmospheric pressure plasma treatment at normal ambient conditions was applied in various textile materials, namely: polyamide, polyester, acrylics and wool. The pre-treated textile materials were characterized using advanced instrumental techniques including X-ray photoelectronic spectroscopy (XPS), differential scanning calorimetry (DSC) atomic force microscopy (AFM) and scanning electron microscopy (SEM). Wettability analysis with different liquids was conducted to study static contact angle as well as surface energy and adhesion work of the plasma-treated fibrous materials. Chemical and physical characterization of the fabric confirmed significant surface alteration. Surface modification concerning the improvement of adhesion regarding a functionalizing substance, i.e. phase change materials (PCM) microcapsules was also investigated