ICAR: endoscopic skull‐base surgery

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Scorpion fluorescence and reaction to light

Scorpions are largely solitary, nocturnal arachnids that glow a bright cyan-green under UV light. The function of this fluorescence is a mystery. Previous studies of four species from three families have shown that scorpion lateral and medial eyes are maximally sensitive to green light (around 500 nm) and secondarily to UV (350-400 nm). Scorpions are negatively phototactic, and we used this behaviour to assay the responses of desert grassland scorpions, Paruroctonus utahensis, to 395 nm UV light, 505 nm cyan-green light, 565 nm green light and no light within small, circular arenas. Based on the eye sensitivity data, we predicted maximal response to 505 nm, followed by lower responses to 395 and 565 nm. In our experiments, however, scorpions responded most intensely (abrupt bouts of locomotory activity) to 395 nm and 505 nm. Next, we ran trials under 395 and 505 nm on scorpions with their eyes blocked. Scorpions with blocked eyes were much less likely to move under 505 nm than under 395 nm and were much less likely to move under 505 nm than were control animals (those without their eyes blocked). These results suggest an active role for fluorescence in scorpion light detection. Other studies indicate that photosensitive elements in scorpion tails are sensitive to green light. We therefore propose that the cuticle may function as a whole-body photon collector, transducing UV light to cyan-green before relaying this information to the central nervous system. Scorpions may use this information to detect shelter, as blocking any part of the cuticle could diminish the signa

Fluorescent in situ hybridization employing the conventional NBT/BCIP chromogenic stain

In situ hybridization techniques typically employ chromogenic staining by enzymatic amplification to detect domains of gene expression. We demonstrate the previously unreported near infrared (NIR) fluorescence of the dark purple stain formed from the commonly used chromogens, nitro blue tetrazolium (NBT) and 5-bromo-4-chloro-3-indolyl phosphate (BCIP). The solid reaction product has significant fluorescence that enables the use of confocal microscopy to generate high-resolution three-dimensional (3-D) imaging of gene expression

Silver Nanoparticle Synthesis via Photochemical Reduction with Sodium Citrate

The aim of this paper is to provide a simple and efficient photoassisted approach to synthesize silver nanoparticles, and to elucidate the role of the key factors (synthesis parameters, such as the concentration of TSC, irradiation time, and UV intensity) that play a major role in the photochemical synthesis of silver nanoparticles using TSC, both as a reducing and stabilizing agent. Concomitantly, we aim to provide an easy way to evaluate the particle size based on Mie theory. One of the key advantages of this method is that the synthesis can be “activated” whenever or wherever silver nanoparticles are needed, by premixing the reactants and irradiating the final solution with UV radiation. UV irradiance was determined by using Keitz’s theory. This argument has been verified by premixing the reagents and deposited them in an enclosed space (away from sunlight) at 25 °C, then checking them for three days. Nothing happened, unless the sample was directly irradiated by UV light. Further, obtained materials were monitored for 390 days and characterized using scanning electron microscopy, UV-VIS, and transmission electron microscopy

Phase Separation within a Binary Self-Assembled Monolayer on Au{111} Driven by an Amide-Containing Alkanethiol

We report the phase separation of a self-assembled monolayer formed from a binary mixture of adsorbates, n-decanethiol, and an amide-containing alkanethiol of similar length (3-mercapto-N-nonylpropionamide), as studied by scanning tunneling microscopy. While mixtures of n-alkanethiols of similar length (i.e., n-decanethiol and n-dodecanethiol) show no phase separation, the introduction of a hydrogen-bonding functionality buried deep within the film induces the formation of single-component domains on the nanometer scale. Phase separation occurs at all relative compositions studied, and for these molecules maintains the same exposed terminal functionality across the entire film. In nonequimolar concentrations of adsorbates, we observe that the solution component present in greater concentration will dominate the composition of the adsorbed monolayer in super proportion to that in solution, consistent with enthalpic contributions from both the solvent and intermolecular interactions of adsorbates

A systematic review of the endoscopic repair of cerebrospinal fluid leaks

Objectives: To provide an up-to-date review of the literature on the safety and efficacy of the endoscopic technique for cerebrospinal (CSF) leak repairs. Data Sources: PubMed, Medline/Old Medline, and Cochrane Central databases. Review Methods: Using the above outlined data sources, studies involving the endoscopic repair of CSF leaks were reviewed independently by 2 researchers. Studies included met the following criteria: full-text article written in the English language, at least 5 human patients undergoing purely endoscopic surgical repair of a CSF leak, and documented follow-up. Data extracted included leak etiology, presentation and location, the use of imaging, intrathecal fluorescein, and adjunctive measures as well as the success rate of the repair. Results: Fifty-five studies, involving 1778 fistulae repairs, were included for analysis. Spontaneous leaks were most prevalent, with the ethmoid roof and sphenoid the most common sites involved. The overall success rate of repair was high at 90% for primary and 97% for secondary repairs. A low complication rate of less than 0.03% was reported. Conclusion: The endoscopic repair of CSF fistula is both safe and effective and should be considered the standard of care for most cases. Evidence supporting adjunctive measures such as lumbar drains and antibiotics remains limited despite their common use.Alkis J. Psaltis, Rodney J. Schlosser, Caroline A. Banks, James Yawn, and Zachary M. Sole