Direct electrical modulation of surface response in a single plasmonic nanoresonator

Classical electrodynamics describes the optical response of macroscopic systems, where the boundaries between materials is treated as infinitesimally thin. However, due to the quantum nature of electrons, interfaces acquires a finite thickness. To include non-classical surface effects in the framework of Maxwell's equations, surface-response functions can be introduced, also known as Feibelman $d$-parameters. Surface response impacts systems with strong field localization at interfaces, which is encountered in noble metal nanoparticles supporting surface plasmon polaritons. However, studying surface response is challenging as it necessitates sub-nanometer control of geometric features, e.g. the gap size in a dimer antenna, while minimizing uncertainties in morphology. In contrast, electrical gating is convenient since the static screening charges are confined exclusively to the surface, which alleviates the need for precise control over the morphology. Here, we study the perturbation of Feibelman $d$-parameters by direct electric charging of a single plasmonic nanoresonator and investigate the resulting changes of the resonance in experiment and theory. The measured change of the resonance frequency matches the theory by assuming a perturbation of the tangential surface current. However, we also observe an unforeseen narrowing in the resonance width when adding electrons to the surface of a plasmonic nanoresonator. These reduced losses cannot be explained by electron spill-out within the local-response approximation (LRA). Such an effect is likely caused by nonlocality and the anisotropy of the perturbed local permittivity. Our findings open up possibilities to reduce losses in plasmonic resonators and to develop ultrafast and extremely small electrically driven plasmonic modulators and metasurfaces by leveraging electrical control over non-classical surface effects.Comment: 10 pages, 3 figures, 15 pages Supplementar

Tobacco Smoke Mediated Induction of Sinonasal Microbial Biofilms

Cigarette smokers and those exposed to second hand smoke are more susceptible to life threatening infection than non-smokers. While much is known about the devastating effect tobacco exposure has on the human body, less is known about the effect of tobacco smoke on the commensal and commonly found pathogenic bacteria of the human respiratory tract, or human respiratory tract microbiome. Chronic rhinosinusitis (CRS) is a common medical complaint, affecting 16% of the US population with an estimated aggregated cost of $6 billion annually. Epidemiologic studies demonstrate a correlation between tobacco smoke exposure and rhinosinusitis. Although a common cause of CRS has not been defined, bacterial presence within the nasal and paranasal sinuses is assumed to be contributory. Here we demonstrate that repetitive tobacco smoke exposure induces biofilm formation in a diverse set of bacteria isolated from the sinonasal cavities of patients with CRS. Additionally, bacteria isolated from patients with tobacco smoke exposure demonstrate robust in vitro biofilm formation when challenged with tobacco smoke compared to those isolated from smoke naïve patients. Lastly, bacteria from smoke exposed patients can revert to a non-biofilm phenotype when grown in the absence of tobacco smoke. These observations support the hypothesis that tobacco exposure induces sinonasal biofilm formation, thereby contributing to the conversion of a transient and medically treatable infection to a persistent and therapeutically recalcitrant condition

Eozinofilna upala u alergijskom rinitisu i nosnoj polipozi

On histopathological examination, nasal polyps and nasal mucosa in allergic rhinitis show different forms of pseudostratified respiratory epithelium, whereas the dominant characteristic of lamina propria is an eosinophilic infiltration. The aim of this study was to compare interleukin (IL)-5 and eosinophilic cationic protein (ECP) levels in the nasal fluid of 42 patients: 12 with allergic rhinitis and nasal septal deviation, 17 non-atopic patients with nasal polyposis, and 13 atopic nasal polyp patients were enrolled in this cross-sectional study. Nasal secretion samples were collected a few days before surgery. The levels of IL-5 were measured using fl ow cytometry and the ECP using a commercial ELISA kit. In addition, we counted eosinophils in hematoxylin-and-eosin-stained sections of all nasal polyp and all nasal mucosa samples taken from the inferior nasal turbinates during septoplasty. A significantly higher concentration of IL-5 was found in the nasal fluid of atopic patients with nasal polyposis than in non-atopic nasal polyp patients (p=0.025) and patients with allergic rhinitis (p=0.05). ECP was higher in atopic nasal polyp patients than in patients with allergic rhinitis (p<0.0001) and than in non-atopic nasal polyp patients (p<0.0001). Polyp eosinophils were higher in atopic’ than in non-atopic patients (p<0.0001) and higher than in the mucosa of patients with allergic rhinitis (p<0.0001). These however had signifi cantly more mucosal eosinophils than was found in the polyps of non-atopic patients’ (p=0.025). ECP levels in nasal fl uid and eosinophil counts in tissue specimens correlated well in all three groups of patients. Our study has shown that atopic nasal polyp patients have a higher level of eosinophilic inflammation than non-atopic patients with nasal polyps and patients with allergic rhinitis.Na histopatološkim pregledima nosni polipi, kao i nosna sluznica u alergijskom rinitisu pokazuju različite oblike pseudoslojevitog respiracijskog epitela, dok je osnovna karakteristika lamine proprije infiltracija eozinofilima. Cilj ove studije bio je usporediti koncentracije interleukina 5 (IL-5) i eozinofilnoga kationskog proteina (ECP) u nosnome sekretu pacijenata s alergijskim rinitisom, neatopičnih i atopičnih pacijenata s nosnom polipozom, kao i usporediti broj eozinofi la u tkivu nosnih polipa/nosne sluznice ovih pacijenata. Četrdeset dvoje (n=42) pacijenata, 12-ero s alergijskim rinitisom i devijacijom nosnog septuma, 17-ero neatopičnih pacijenata s nosnom polipozom i 13-ero atopičnih pacijenata s nosnom polipozom bilo je uključeno u ovu presječnu studiju. Uzorci nosnog sekreta bili su skupljeni iz nosnih šupljina svih ispitanika nekoliko dana prije kirurškog liječenja. Koncentracije IL-5 mjerene su metodom protočne citometrije, dok su koncentracije ECP mjerene komercijalnim ELISA-kitom. Eozinofi li su brojeni u svim uzorcima tkiva nosnih polipa, kao i u svim uzorcima tkiva sluznice uzetih s donje nosne školjke tijekom septoplastike. Značajno više koncentracije IL-5 izmjerene su u nosnom sekretu atopičnih pacijenata s nosnom polipozom u usporedbi s neatopičnim pacijentima s nosnom polipozom (p=0,025) i pacijentima s alergijskim rinitisom (p=0,05). Naši su rezultati pokazali više koncentracije ECP u atopičnih pacijenata s nosnom polipozom nego u pacijenata s alergijskim rinitisom (p<0,0001) i u usporedbi s nealergičnim pacijentima s nosnom polipozom (p<0,0001). Veći broj eozinofi la izbrojen je u tkivu polipa atopičnih pacijenata nego u tkivu polipa neatopičnih pacijenata (p<0,0001), kao i u sluznici pacijenata s alergijskim rinitisom (p<0,0001). U nosnoj sluznici pacijenata s alergijskim rinitisom našli smo značajno veći broj eozinofila nego u polipima neatopičnih pacijenata s nosnim polipima (p=0,025). Konačno, našli smo pozitivnu korelaciju između nivoa ECP u nosnom sekretu i broja eozinofila u uzorcima tkiva u sve tri skupine ispitanika. Zaključili smo da atopični pacijenti s nosnom polipozom imaju viši stupanj eozinofilne upale u usporedbi s neatopičnim pacijentima s nosnim polipima i s pacijentima s alergijskim rinitisom

The dynamics of soluble Fas/APO 1 apoptotic biochemical marker in acute ischemic stroke patients

ABSTRACT Purpose: Until recently, neuronal death in ischemic stroke infarction was ascribed exclusively to necrotic process. However, experimental animal models of cerebral ischemia suggest apoptosis to play a role in the pathogenesis of cerebral infarction. The aim of this study was to determine the level and monitor the dynamics of soluble Fas/APO 1 (sFas/APO 1) in serum and cerebrospinal fluid of acute ischemic stroke patients. Material and Methods: This prospective study included 23 patients with first ever, computed tomography verified acute ischemic stroke and 20 control subjects with other functional neurologic disorders. Serum and cerebrospinal fluid sFas/APO 1 levels were determined on several occasions. Blood samples were obtained on day 1, 3 and 12, and lumbar puncture on day 3 and 12 of disease onset. Quantitative sandwich ELISA method was used on sFas/APO 1 determination. Results: On day 1 of disease onset, serum and cerebrospinal fluid sFas/APO 1 levels were significantly higher in stroke patients as compared to control subjects, and then gradually declined during the period of monitoring. Conclusion: Study results confirmed the dynamic pattern of sFas/APO 1 in serum and cerebrospinal fluid of patients with acute ischemic stroke, suggesting the possible role of apoptosis in the pathogenesis of cerebral infarction