Multimodal nerve injection provides noninferior analgesic efficacy compared with interscalene nerve block after arthroscopic rotator cuff repair.

PURPOSE: This randomized noninferiority trial aimed to evaluate whether combined suprascapular, axillary nerve, and the articular branch of lateral pectoral nerve block (3NB) is noninferior to interscalene nerve block (ISB) for pain control after arthroscopic rotator cuff repair (ASRCR). MATERIALS AND METHODS: Eighty-five patients undergoing ASRCR were randomized to either 3NB (n = 43) or ISB (n = 42) group. We used 5 and 15 ml of 0.2% ropivacaine for each nerve in the 3NB and ISB groups, respectively. The primary outcome was the visual analog scale (VAS) pain score at 4 h postoperatively measured assessed on an 11-point scale (ranging from 0 = no pain to 10 = worst pain) that was analyzed using noninferiority testing. The secondary outcome was VAS pain scores in the recovery room and at 8, 12, 24, 36, 48, and 72 h postoperatively. Rebound pain, IV-PCA usage during 48 h, dyspnea, muscle weakness, and satisfaction were evaluated. RESULTS: Regarding the primary outcome, the mean difference in VAS pain scores between the 3NB (2.5 ± 1.6) and ISB (2.2 ± 2.3) groups at 4 h postoperatively was 0.3, with a 95% confidence interval (CI) of -0.56 to 1.11. The upper limit of 95% CI is lower than the noninferiority margin of 1.3 (p < 0.001). At all other time points, except in the recovery room, 3NB showed noninferior to ISB. Rebound pain, IV-PCA usage during the second 24 h, and muscle weakness were lower in the 3NB group (all p < 0.005). The satisfaction was similar in both groups (p = 0.815). CONCLUSION: Combined 3NB is noninferior to ISB in terms of pain control after ASRCR; and is associated with low levels of rebound pain, IV-PCA usage, and muscle weakness. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

A modeling approach to energy savings of flying Canada geese using computational fluid dynamics.

A flapping flight mechanism of the Canada goose (Branta canadensis) was estimated using a two-jointed arm model in unsteady aerodynamic performance to examine how much energy can be saved in migration. Computational fluid dynamics (CFD) was used to evaluate airflow fields around the wing and in the wake. From the distributions of velocity and pressure on the wing, it was found that about 15% of goose flight energy could be saved by drag reduction from changing the morphology of the wing. From the airflow field in the wake, it was found that a pair of three-dimensional spiral flapping advantage vortices (FAV) was alternately generated. We quantitatively deduced that the optimal depth (the distance along the flight path between birds) was around 4m from the wing tip of a goose ahead, and optimal wing tip spacing (WTS, the distance between wing tips of adjacent birds perpendicular to the flight path) ranged between 0 and -0.40m in the spanwise section. It was found that a goose behind can save about 16% of its energy by induced power from FAV in V-formation. The phase difference of flapping between the goose ahead and behind was estimated at around 90.7° to take full aerodynamic benefit caused by FAV.

Enhancement of localized surface plasmon resonance detection by incorporating metal-dielectric double-layered subwavelength gratings.

In this study, we investigated the enhanced sensing performance of a localized surface plasmon resonance (LSPR) biosensor by employing metal-dielectric double-layered subwavelength grating structures. The numerical results showed that the LSPR substrate with a dielectric spacer can provide not only a better sensitivity but also a significantly improved reflectance characteristic. While the presence of metallic gratings leads to a broad and shallow reflectance curve inevitably, the dielectric spacer can prevent the propagating surface plasmons from being interfered by the locally enhanced fields excited at the gold gratings, finally resulting in a strong and deep absorption band at resonance. Therefore, the proposed structure could potentially open a new possibility of the enhanced LSPR detection for monitoring biomolecular interactions of low molecular weights.

Surface-enhanced localized surface plasmon resonance biosensing of avian influenza DNA hybridization using subwavelength metallic nanoarrays.

We demonstrated enhanced localized surface plasmon resonance (SPR) biosensing based on subwavelength gold nanoarrays built on a thin gold film. Arrays of nanogratings (1D) and nanoholes (2D) with a period of 200 nm were fabricated by electron-beam lithography and used for the detection of avian influenza DNA hybridization. Experimental results showed that both nanoarrays provided significant sensitivity improvement and, especially, 1D nanogratings exhibited higher SPR signal amplification compared with 2D nanohole arrays. The sensitivity enhancement is associated with changes in surface-limited reaction area and strong interactions between bound molecules and localized plasmon fields. Our approach is expected to improve both the sensitivity and sensing resolution and can be applicable to label-free detection of DNA without amplification by polymerase chain reaction.

Effect of target localization on the sensitivity of a localized surface plasmon resonance biosensor based on subwavelength metallic nanostructures.

A localized surface plasmon resonance (LSPR) biosensor using surface relief nanostructures was investigated to evaluate the importance of target localization on the sensitivity enhancement. The LSPR device was modeled as periodic metallic nanowires with a square profile on a gold film and the target as a self-assembled monolayer in buffer solution. The numerical results using rigorous coupled-wave analysis and the finite-difference time domain method demonstrated localized plasmonic fields induced by the surface nanostructure from which the effect of target localization on the sensitivity was quantitatively analyzed. Interestingly, it was found that target localization on nanowire sidewalls improves sensitivity significantly because of strong overlap with localized plasmonic fields. An LSPR structure optimized for a localized target on sidewalls provides sensitivity enhancement per unit target volume by more than 20 times in water ambience.