Spectral clustering algorithm for the allometric extension model

The spectral clustering algorithm is often used as a binary clustering method for unclassified data by applying the principal component analysis. To study theoretical properties of the algorithm, the assumption of conditional homoscedasticity is often supposed in existing studies. However, this assumption is restrictive and often unrealistic in practice. Therefore, in this paper, we consider the allometric extension model, that is, the directions of the first eigenvectors of two covariance matrices and the direction of the difference of two mean vectors coincide, and we provide a non-asymptotic bound of the error probability of the spectral clustering algorithm for the allometric extension model. As a byproduct of the result, we obtain the consistency of the clustering method in high-dimensional settings.Comment: 20 page

Real-Time Polarization-Resolved Imaging of Living Tissues Based on Two-Photon Excitation Spinning-Disk Confocal Microscopy

Laser scanning microscopy using high-peak-power ultrashort near infrared light pulses can visualize biological microstructures by utilizing non-linear optical processes, such as multi-photon excitation and sum frequency generation. Here we introduced a polarization-resolving detection methodology for a laser scanning microscopy system equipped with a spinning-disk confocal scanner. The developed system achieved high-speed intravital imaging of living tissues with resolving their signals to orthogonally polarized components. First, we applied the system to a liposomal vesicle labeled with the fluorescent lipophilic dye and confirmed the orientation map of the lipid bilayer. Next, by detecting polarization-resolved second harmonic generation signals, the structural orientations of the collagen fibers in fixed mouse tissues were visualized without exogenous or genetic fluorophore labeling. Finally, we demonstrated in vivo polarization-resolved second harmonic generation imaging of the collagen fibers in the mouse skeletal muscles at a 56 Hz temporal resolution. We expect that our developed methodology can achieve real-time visualization, thus, revealing the conformational changes of supramolecular structures in living animals

A comparison of the force applied on oral structures during intubation attempts between the Pentax-AWS airwayscope and the Macintosh laryngoscope: a high-fidelity simulator-based study

Objective: We sought to determine whether the use of Pentax-AWS Airwayscope (AWS) applied less force on oral structures during intubation attempts than a conventional direct laryngoscope (DL). Design: Prospective cross-over study. Participants: A total of 37 physicians (9 transitional-year residents, 20 emergency medicine residents and 8 emergency physicians) were enrolled. Interventions We used four simulation scenarios according to the difficulty of intubation and devices and used a high-fidelity simulator to quantify the forces applied on the oral structures. Outcome measures Primary outcomes were the maximum force applied on the maxillary incisors and tongue. Other outcomes of interest were time to intubation and glottic view during intubation attempts. Results: The maximum force applied on the maxillary incisors in the normal airway scenario was higher with the use of AWS than that with DL (107 newton (N) vs 77 N, p=0.02). By contrast, the force in the difficult airway scenario was significantly lower with the use of AWS than that of the DL (89 N vs 183 N, p<0.01). Likewise, the force applied on the tongue was significantly lower with the use of AWS than the use of DL in both airway scenarios (11 N vs 27 N, p<0.001 in the normal airway scenario; 12 N vs 40 N, p<0.01 in the difficult airway scenario). Conclusions: The use of AWS during intubation attempts was associated with decreased forces applied to oral structures in the simulated difficult airway scenario

Methylglyoxal reduces molecular responsiveness to 4 weeks of endurance exercise in mouse plantaris muscle

Endurance exercise triggers skeletal muscle adaptations, including enhanced insulin signaling, glucose metabolism, and mitochondrial biogenesis. However, exercise-induced skeletal muscle adaptations may not occur in some cases, a condition known as exercise-resistance. Methylglyoxal (MG) is a highly reactive dicarbonyl metabolite and has detrimental effects on the body such as causing diabetic complications, mitochondrial dysfunction, and inflammation. This study aimed to clarify the effect of methylglyoxal on skeletal muscle molecular adaptations following endurance exercise. Mice were randomly divided into 4 groups (n = 12 per group): sedentary control group, voluntary exercise group, MG-treated group, and MG-treated with voluntary exercise group. Mice in the voluntary exercise group were housed in a cage with a running wheel, while mice in the MG-treated groups received drinking water containing 1% MG. Four weeks of voluntary exercise induced several molecular adaptations in the plantaris muscle, including increased expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α), mitochondria complex proteins, toll-like receptor 4 (TLR4), 72-kDa heat shock protein (HSP72), hexokinase II, and glyoxalase 1; this also enhanced insulin-stimulated Akt Ser473 phosphorylation and citrate synthase activity. However, these adaptations were suppressed with MG treatment. In the soleus muscle, the exercise-induced increases in the expression of TLR4, HSP72, and advanced glycation end products receptor 1 were inhibited with MG treatment. These findings suggest that MG is a factor that inhibits endurance exercise-induced molecular responses including mitochondrial adaptations, insulin signaling activation, and the upregulation of several proteins related to mitochondrial biogenesis, glucose handling, and glycation in primarily fast-twitch skeletal muscle

Glycative stress and skeletal muscle dysfunctions: as an inducer of "Exercise-Resistance."

Skeletal muscle, the largest tissue in the body, is often overlooked for its role as a locomotor organ, however over the past few decades it has been revealed that it also has an important role as a metabolic organ. In recent years, its role as an endocrine organ that controls the homeostatic functions of organs throughout the body mediated by myokine secretion has come under close scrutiny. Skeletal muscle is indispensable for our daily life activities, and in order to maintain its function, it is necessary to understand the factors that deteriorate muscle function and establish a countermeasure. Glycative stress has recently received attention as a factor that impairs skeletal muscle function. Accumulation of advanced glycation end products (AGEs) in skeletal muscle impairs contractile function and myogenic potential. Furthermore, AGEs in the blood elicit inflammatory signals through binding to RAGE (Receptor for AGEs) expressed on muscle cells, resulting in muscle proteolysis. Habitual exercise is important to mitigate the negative effects of such glycative stress on skeletal muscle. On the other hand, it is known that the beneficial effects of exercise vary among individuals. The state in which the effects of exercise are difficult to obtain is called "exercise-resistance, " and we hypothesize that glycative stress may be one of the causes of exercise-resistance. In this paper, we will discuss the possibility of glycative stress as an inducer of exercise resistance and summarize its impacts on skeletal muscle

Electrosynthesis of Conducting Polymers in Lecithin Liquid Crystal Reaction Field

Lecithin is a biological material that exhibits lyotropic liquid crystal form at certain concentrations in water. Specifically, lecithin forms lamellar structures like a smectic phase layers. We describe electro-oxidative preparation of polymers such as polyaniline (PANI), poly(ethylenedioxythiophene) (PEDOT), and polypyrrole (PPy) in a lecithin liquid crystal matrix. Cross-shaped images (Maltese crosses) derived from lamellar structures were observed for the resultant polymer film with a polarizing optical microscopy under crossed Nicol condition. Lecithin lamellar structure in the water was transcribed to the resultant polymers during the electropolymerization. This research demonstrates transcription of a liquid crystal aggregation form of biomaterials onto synthetic polymers through electrochemical process

Multiple failed intubation attempts are associated with decreased success rates on the first rescue intubation in the emergency department: a retrospective analysis of multicentre observational data

Background: Although the international guidelines emphasize early and systematic use of rescue intubation techniques, there is little evidence to support this notion. We aimed to test the hypothesis that preceding multiple failed intubation attempts are associated with a decreased success rate on the first rescue intubation in emergency departments (EDs). Methods: We analysed data from two multicentre prospective registries designed to characterize current ED airway management in Japan between April 2010 and June 2013. All patients who underwent a rescue intubation after a failed attempt or a series of failed attempts were included for the analysis. Multiple failed intubation attempts were defined as ≥2 consecutive failed intubation attempts before a rescue intubation. Primary outcome measure was success rate on the first rescue intubation attempt. Results: Of 6,273 consecutive patients, 1,151 underwent a rescue intubation. The success rate on the first rescue intubation attempt declined as the number of preceding failed intubation attempts increased (81% [95% CI, 79%-84%] after one failed attempt; 71% [95% CI, 66%-76%] after two failed attempts; 67% [95% CI, 55%-78%] after three or more failed attempts; Ptrend <0.001). In the multivariable analysis adjusting for age, sex, principal indication, change in methods, devices, and intubator specialty, and clustering of patients within EDs, success rate on the first rescue intubation after two failed attempts was significantly lower (OR, 0.56; 95% CI, 0.41-0.77) compared to that after one failed attempt. Similarly, success rate on the first rescue intubation attempt after three or more failed attempts was significantly lower (OR, 0.49; 95% CI, 0.25-0.94) compared to that after one failed attempt. Conclusion: Preceding multiple failed intubation attempts was independently associated with a decreased success rate on the first rescue intubation in the ED