Another One Busts The Dust

Brown dwarfs are substellar objects with core temperatures insufficient for sustained hydrogen fusion. Their physical properties such as mass, temperature, and radius are similar to those of gas giant planets, so studying brown dwarfs may also benefit exoplanet studies. There is a population of \u27red\u27 L dwarfs, which have redder J - K colors in the near-infrared than normal objects. Red L dwarfs include young, low-gravity objects, which are systematically red, and red field-gravity objects. The observed reddening in L dwarfs is not well explained by current atmosphere models. We present an analysis of red L dwarfs using our model which includes small, sub-micron size dust particles in the upper atmosphere in addition to the cloud decks common to all L dwarfs which consist of larger particles. We hypothesize that the red NIR colors of some L dwarfs could be explained by a dust haze of small particles. We developed a model which combines Mie theory and Hansen particle size distributions to reproduce the extinction due to the proposed dust haze. We apply our analysis to 20 young L dwarfs and 36 red field L dwarfs. We constrain the properties of the dust haze including particle size distribution and column density using Markov-Chain Monte Carlo methods. We find that sub-micron range silicate grains reproduce the observed reddening. We also find that Hansen particle size distributions reproduce the shape of the observed reddening better than power law particle size distributions. Current brown dwarf atmosphere models include large grain (~ 10 microns) dust clouds but not ISM-size small dust grains. Our results provide a proof of concept and motivate a combination of large and small dust grains in brown dwarf atmosphere models. Finally, we discuss our future prospects and possible application of the dust haze analysis for atmospheric models of brown dwarfs and exoplanets, and variability in brown dwarfs

Pullout Repair Associated With a Bridging Suture Using FiberLink for the Medial Meniscus Posterior Horn/Root Tear

Transtibial pullout repair for the medial meniscus (MM) posterior root tear has become the gold standard. However, an optimal repair technique has not yet been established for MM posterior horn (MMPH) tear with a sufficient root remnant. We describe a pullout repair technique associated with a bridging suture using FiberLink (Arthrex, Naples, FL) for the MMPH tear. In this bridging suture technique, the simple cinch stitch is applied to the root remnant and MMPH. The loop end of the FiberLink is inserted into the MMPH, and its free-end is inserted into the root remnant. Next, the suture is tensioned and tied on the superior surface of the MMPH. The bridging suture and the additional simple stitch applied to the MMPH are pulled out through the tibial tunnel and fixed to the tibia on an expected tension. This technique might lead to better meniscal healing of the tear site, because it involves bridging of the MMPH and root remnant, and lower risk of suture cut-out owing to the biomechanical strength

Influence of Acute Resistance Training on Memory, Executive Function, and Mood

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A newly-developed guide can create tibial tunnel at an optimal position during medial meniscus posterior root repairs

Background During transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs), accurate tibial tunnel creation within the anatomic MM posterior root attachment seems critical. This study aimed to evaluate the tibial tunnel position created by a newly-developed Precision guide during pullout repair of MMPRTs. Methods In 40 patients who underwent transtibial pullout repairs, the tibial tunnel was created using the Unicorn Meniscal Root (UMR) (n = 20) or Precision guide (n = 20). Three-dimensional computed tomography images of the tibial surface were evaluated postoperatively, using Tsukada's measurement method. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines corresponding to anatomic bony landmarks. The expected anatomic center (AC) and the tibial tunnel center (TC) were evaluated using the percentage-based posterolateral location on the tibial surface. The difference in the mediolateral and anteroposterior percentage distance between the AC and TC was calculated, as was the absolute distance between the AC and TC. Results The mean AC was located 77.4% posterior and 40.1% lateral. The mean TC was similar in the UMR and Precision guide groups. There was no significant difference in the mediolateral percentage distance (UMR 3.9% vs. Precision 3.6%, p = 0.405), but a significant difference was observed in the anteroposterior percentage distance (UMR 3.5% vs. Precision 2.6%, p = 0.031). The mean absolute distance between the AC and TC was 3.9 mm and 3.5 mm (UMR and Precision guide groups, respectively) (p = 0.364). Conclusions The new Precision guide can create tibial tunnel in an optimal and stable position during pullout repair of MMPRTs

血液脳関門透過性を有するヒストン脱アセチル化酵素阻害剤の探索研究 [論文要旨及び審査の要旨]

関西大

Medial meniscus posterior root repairs: A comparison among three surgical techniques in short-term clinical outcomes and arthroscopic meniscal healing scores

Background Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason–Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs. Methods Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason–Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0–10 points) were evaluated at second-look arthroscopies. Results No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores. Conclusions This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs

Tibial Tunnel Positioning Using the Posterolateral (PL) Divergence Guide in Anterior Cruciate Ligament Reconstruction

The aim of this study was to evaluate tunnel coalition and inter-tunnel distance by comparing the tibial tunnel position in double-bundle anterior cruciate ligament (ACL) reconstruction performed with a conventional guide versus a posterolateral (PL) divergence (PLD) guide. Subjects were 43 patients (ACL tip aimer: 20 knees; PLD guide: 23 knees) who underwent double-bundle ACL reconstruction between September 2014 and December 2017. In all cases, the tibial tunnel position, tunnel edge distance and tunnel angles were evaluated based on CT images. Clinical outcome was evaluated using the Lachman test, pivot-shift test, and Lysholm score. Tibial tunnel positions were similar between the conventional and PLD guide groups, while tibial tunnel edge distance was significantly less in the conventional group. Tunnel coalition was observed in 5 knees in the conventional and no knees in the PLD guide group. Distance between two tibial tunnel centers was 9.1 mm for the tip aimer, and 10.5 mm for the PLD guide. Creation of the PL tunnel tended to involve insertion from a more medial aspect for the PLD guide group than the conventional guide group. No differences in clinical outcomes were noted. The PLD guide can be used to create anatomically-positioned PL tunnels, and reduce the probability of occurrence of tunnel coalition