Terahertz diffractive structures for compact in-reflection inspection setup.

Two diffractive optical elements are used to create a compact raster THz scanning setup in reflective configuration. The first one focuses the radiation into the small focal spot on the sample, while the second one collects reflected radiation and focuses it on the detector. To assure small size of the setup and large apertures of optical elements, structures work in the off-axis geometry. Thus, the focal spot is formed 100 mm after and 60 mm below the optical axis of the element, which measures 75 mm in diameter. The designed iterative algorithm allows further minimization of these values.

Epidemiology, clinical history and microbiology of peritonsillar abscess.

The purpose of this investigation was to explore the epidemiology, clinical history and microbiology of peritonsillar abscess (PTA). A retrospective review of PTA cases treated at the Department of Otolaryngology, Regional Specialist Hospital in Radom, Poland between 1st October 2003 and 30th September 2013 was undertaken. A total of 111 PTA patients were admitted. The study population consisted of 57.7 % males and 42.3 % females, with an average age of 31.0 (range 5-78) years. Smokers comprised 22.0 % of the study group. The seasonal variation of PTA was statistically insignificant (p = 0.45). Recurrent tonsillitis occurred in 35.5 % of patients. In comparison with the rest of the study population, patients with a history of recurrent pharyngotonsillitis had higher incidence of previous PTA episodes [odds ratio (OR) 17.8, 95 % confidence interval (CI) 2.1-148.7, p = 0.001]. Also, they were more frequently treated with antibiotics prior to hospitalisation (OR 4.6, 95 % CI 2.0-10.9, p = 0.0005) and had significantly longer hospital stay (p = 0.03). Bacterial cultures of abscess aspirates were performed in 40.5 % of patients. Monomicrobial growth was detected in 77.8 % of aerobic cultures. Streptococcus pyogenes, growing most frequently in monoculture, was found in 28.9 % of aerobic cultures. PTA patients with and without recurrent pharyngotonsillitis differed with regard to clinical history and course of disease. The percentage of smokers among PTA patients was lower than that described in the literature. Monomicrobial growth predominated in PTA aspirate cultures. S. pyogenes proved to be the most frequent pathogen.

High order kinoforms as a broadband achromatic diffractive optics for terahertz beams.

We discuss thin optical structures that allow chromatic aberrations to be avoided in the THz domain. The paper contains the theoretical considerations, computer modeling and experimental evaluation of the high order kinoform diffractive elements in the THz range. According to the obtained results application of the high order kinoforms enables broadband operation in the THz range.

THz, Raman, IR and DFT studies of noncentrosymmetric metal dicyanamide frameworks comprising benzyltrimethylammonium cations.

We report density functional theory (DFT) studies of vibrational modes for benzyltrimethylammonium cations (BeTriMe+) as well as THz, IR and Raman studies of [BeTriMe][M(dca)3(H2O)] (dca = N(CN)2-, dicyanamide; M = Mn2+, Co2+, Ni2+) and their anhydrous analogues. These studies show that the anhydrous BeTriMeMn and BeTriMeNi have the same or very similar structures and loss of water molecules leads to significant changes in the metal-dicyanamide frameworks. In particular, the number of dca modes decreases, suggesting increase of crystal symmetry, probablly related with decrease in the number of non-equivalent dca bridges from two to one. Although it is possible that dehydration leads to a replacement of the coordinate Mn-O (Ni-O) bonds by Mn-N (Ni-N) bonds, wherein N atoms come from the C≡N groups of previously non-bridged dca units, reversibility of the dehydration process indicates that such new bonds are either not formed or are very weak. The anhydrous Mn and Ni compounds undergo similar reversible phase transitions to lower symmetry phases. The driving force for these transitions is most likely ordering of dca linkers but this process is accompanied by weak distortion of the metal-dicyanamide frameworks. In the case of BeTriMeCo, the loss of water molecules also leads to significant changes in the cobalt-dicyanamide framework. However, the structure of this analogue is different from the structures of the Mn and Ni counterparts, the number of unique dca linkers is preserved and the dehydration process is irreversible, suggesting more drastic rearrangement of the metal-dicynamide framework.

Regulation of NMDA receptor activity by F-actin and myosin light chain kinase.

The postsynaptic density (PSD) at excitatory dendritic synapses comprises a protein complex of glutamate receptors, scaffolding elements, and signaling enzymes. For example, NMDA receptors (NMDARs) are linked to several proteins in the PSD, such as PSD-95, and are also tethered via binding proteins such as alpha-actinin directly to filamentous actin of the cytoskeleton. Depolymerization of the cytoskeleton modulates the activity of NMDARs, and, in turn, strong activation of NMDARs can trigger depolymerization of actin. Myosin, the motor protein of muscular contraction and nonmuscle motility, is also associated with NMDARs and the PSD. We show here that constitutively active myosin light chain kinase (MLCK) enhances NMDAR-mediated whole-cell and synaptic currents in acutely isolated CA1 pyramidal and cultured hippocampal neurons, whereas inhibitors of MLCK depress these currents. This MLCK-dependent regulation was observed in cell-attached patches but was lost after excision to inside-out patches. Furthermore, the enhancement induced by constitutively active MLCK and the depression of MLCK inhibitors were eliminated after depolymerization of the cytoskeleton. NMDARs and MLCK did not colocalize in clusters on the dendrites of cultured hippocampal neurons, further indicating that the effects of MLCK are mediated indirectly via actomyosin. Our results suggest that MLCK enhances actomyosin contractility to either increase the membrane tension on NMDARs or to alter physical relationships between the actin cytoskeleton and the linker proteins of NMDARs.