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Melanopsin signaling within intrinsically photosensitive retinal ganglion cell (ipRGC) subtypes impacts a broad range of behaviors from circadian photoentrainment to conscious visual perception. Yet, how melanopsin phototransduction within M1-M6 ipRGC subtypes impacts cellular signaling to drive diverse behaviors is still largely unresolved. The identity of the phototransduction channels in each subtype is key to understanding this central question but has remained controversial. In this study, we resolve two opposing models of M4 phototransduction, demonstrating that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are dispensable for this process and providing support for a pathway involving melanopsin-dependent potassium channel closure and canonical transient receptor potential (TRPC) channel opening. Surprisingly, we find that HCN channels are likewise dispensable for M2 phototransduction, contradicting the current model. We instead show that M2 phototransduction requires TRPC channels in conjunction with T-type voltage-gated calcium channels, identifying a novel melanopsin phototransduction target. Collectively, this work resolves key discrepancies in our understanding of ipRGC phototransduction pathways in multiple subtypes and adds to mounting evidence that ipRGC subtypes employ diverse phototransduction cascades to fine-tune cellular responses for downstream behaviors.

Background: Anesthesia trainee may initially take longer time to intubate and unintentionally place the endotracheal tube (ETT) in the esophagus. The present study determined if ultrasound is the fastest method of confirmation of correct placement of ETT compared to capnography, and chest auscultation in trainees. Methods: First year anesthesia residents performed intubation in 120 patients recruited after ethical clearance and informed consent. Time to visualize flutter in trachea, double trachea sign, time to appearance of first and sixth capnography, and time to execute chest auscultation was noted. Results: Ultrasonography was statistically fastest method to determine endotracheal intubation (36.50 ± 15.14 seconds) vs unilateral chest auscultation (50.29 ± 15.50 seconds) vs bilateral chest auscultation (51.90 ± 15.98 seconds) vs capnography first waveform (53.57 ± 15.97 seconds) vs capnography sixth waveform (61.67 ± 15.88 seconds). Conclusion: When teaching endotracheal intubation to novice anesthesia residents using conventional direct laryngoscopy, ultrasonography is the fastest method to confirm correct ETT placement compared to capnograph and chest auscultation. Mentor can guide trainee to direct ETT towards trachea and can promptly detect esophageal intubation by double trachea sign.

We have investigated the effect of applied pressure (P) on the magnetic and superconducting transitions of GdFeCoxAsO (x = 0, 0.1, 1) compounds by measuring the temperature dependence of resistivity. At ambient pressure, GdFeAsO undergoes a spin-density wave transition at associated with the 3d electrons of Fe. Under external pressure, TN decreases from 128.2 K at 0 GPa to 114.5 K at 2.5 GPa at the rate = 6 K/GPa. Unlike GdFeAsO, the isostructural GdCoAsO exhibits a ferrimagnetic ordering of the Co moments at 76 K which decreases from 76 K to 71 K as pressure increases from 0 to 2.5 GPa. For the GdFeCoAsO sample, the superconducting onset temperature Tcon decreases monotonically from 19 to 17.1 K, and the temperature Tczero at which the resistivity disappears decreases from 16.7 to 10.5 K as pressure increases from 0 to 2.9 GPa. For all the three samples, both the value of resistivity and the strength of electron–electron correlation decrease monotonically with increasing pressure. [ABSTRACT FROM AUTHOR]