Role of concealed conduction and allied phenomena in the genesis, maintenance, and termination of cardiac arrhythmias.

Concealed conduction is a common electrocardiographic phenomenon whereby a series of events may occur as a result of incomplete propagation of an impulse. The occurrence, maintenance, and resolution (termination) of several events such as functional block and cardiac arrhythmias are linked to concealed conduction. This phenomenon should be suspected on the surface electrocardiogram whenever an arrhythmic event occurs unexpectedly. Several electrophysiological concepts such as transseptal conduction and linking phenomenon are close allies of concealed conduction. His-bundle electrocardiography and comprehensive electrophysiology may be needed to verify this phenomenon.

Multinomial Logistic Factor Regression for Multi-source Functional Block-wise Missing Data.

Multi-source functional block-wise missing data arise more commonly in medical care recently with the rapid development of big data and medical technology, hence there is an urgent need to develop efficient dimension reduction to extract important information for classification under such data. However, most existing methods for classification problems consider high-dimensional data as covariates. In the paper, we propose a novel multinomial imputed-factor Logistic regression model with multi-source functional block-wise missing data as covariates. Our main contribution is to establishing two multinomial factor regression models by using the imputed multi-source functional principal component scores and imputed canonical scores as covariates, respectively, where the missing factors are imputed by both the conditional mean imputation and the multiple block-wise imputation approaches. Specifically, the univariate FPCA is carried out for the observable data of each data source firstly to obtain the univariate principal component scores and the eigenfunctions. Then, the block-wise missing univariate principal component scores instead of the block-wise missing functional data are imputed by the conditional mean imputation method and the multiple block-wise imputation method, respectively. After that, based on the imputed univariate factors, the multi-source principal component scores are constructed by using the relationship between the multi-source principal component scores and the univariate principal component scores; and at the same time, the canonical scores are obtained by the multiple-set canonial correlation analysis. Finally, the multinomial imputed-factor Logistic regression model is established with the multi-source principal component scores or the canonical scores as factors. Numerical simulations and real data analysis on ADNI data show the proposed method works well.

Triazole-Functionalized Mesoporous Materials Based on Poly(styrene-block-lactic acid): A Morphology Study of Thin Films.

We report the synthesis of poly(styrene-block-lactic acid) (PS-b-PLA) copolymers with triazole rings as a junction between blocks. These materials were prepared via a 'click' strategy which involved the reaction between azide-terminated poly(styrene) (PS-N3) and acetylene-terminated poly(D,L-lactic acid) (PLA-Ac), accomplished by copper-catalyzed azide-alkyne cycloaddition reaction. This synthetic approach has demonstrated to be effective to obtain specific copolymer structures with targeted self-assembly properties. We observed the self-assembly behavior of the PS-b-PLA thin films as induced by solvent vapor annealing (SVA), thermal annealing (TA), and hydrolysis of the as-spun substrates and monitored their morphological changes by means of different microscopic techniques. Self-assembly via SVA and TA proved to be strongly dependent on the pretreatment of the substrates. Microphase segregation of the untreated films yielded a pore size of 125 nm after a 45-min SVA. After selectively removing the PLA microdomains, the as-spun substrates exhibited the formation of pores on the surface, which can be a good alternative to form an ordered pattern of triazole functionalized porous PS at the mesoscale. Finally, as revealed by scanning electron microscopy-energy dispersive X-ray spectroscopy, the obtained triazole-functionalized PS-porous film exhibited some affinity to copper (Cu) in solution. These materials are suitable candidates to further study its metal-caption properties.

Highly Effective Photocontrollable Drug Delivery Systems Based on Ultrasensitive Light-Responsive Self-Assembled Polymeric Micelles: An in Vitro Therapeutic Evaluation.

An ultrasensitive light-responsive block copolymer, a combination of a multiarmed poly(ethylene glycol)-b-poly(caprolactone) polymer as a water-soluble element and maleimide-anthracene linkers as a photosensitive group, was successfully synthesized and rapidly self-assembled to form spherical micellar nanoparticles in aqueous media and phosphate-buffered saline. Their unique characteristics, such as extremely low critical micelle concentration, desirable micellar stability, well-controlled light-responsiveness, tailorable drug-loading content, and ultrasensitive light-induced drug release, make these micelles potential candidates for development of a more effective, safer drug delivery platform for cancer treatment. In vitro studies revealed that the drug-loaded micelles exhibited high structural stability in serum-containing media and very low toxicity toward normal and cancer cells under physiological conditions. Irradiation of cancer cells incubated with the drug-loaded micelles with ultraviolet light at 254 nm for only 10 s triggered rapid and complete release of the drug in the intracellular environment and induced strong antiproliferative/cytotoxic activity. Importantly, real-time cytotoxic assays and fluorescence imaging analysis further demonstrated that the drug-loaded micelles were rapidly taken up into the cytosol or nuclei of the cells, and subsequent ultraviolet exposure induced drug release and apoptotic cell death. Given their simplicity of design, high reliability, and performance, this new light-sensitive micelle may provide a promising route for developing a multifunctional therapeutic nanocarrier system.

Effective low dosage of mepivacaine in ultrasound-guided axillary nerve block: a double-blinded, randomized clinical trial of efficacy in patients undergoing distal upper extremity surgery.

STUDY OBJECTIVE: To evaluate two low-dose volumes (20 mL or 30 mL) of 1.5% mepivacaine solution used for ultrasound-guided axillary blockade for outpatients undergoing distal upper limb surgery. DESIGN: Prospective, double-blinded randomized study. SETTING: Outpatient surgical setting of a university-affiliated hospital. PATIENTS: 64 adult, ASA physical status 1, 2, and 3 patients, aged 28-46 years, scheduled for upper limb surgery. INTERVENTIONS: Patients were randomized to two groups to receive either 20 mL of 1.5% mepivacaine solution (n=31) or 30 mL of 1.5% mepivacaine solution (n=33) for ultrasound-guided axillary plexus blockade. MEASUREMENTS: Block duration, proportion of surgical and functional successful blocks, onset of sensory and motor blockade measured from 0 to 30 minutes following final needle extraction, total amount of preoperative sedative (midazolam), and intraoperative propofol administered were recorded. MAIN RESULTS: Following axillary plexus blockade, neither patient group showed any statistically significant difference in the percentage of functionally successful blockade (30 mL, 100%: 20 mL, 97%; P = 0.48), surgically successful blockade (30 mL, 100%; 20 mL, 94%; P = 0.23), cumulative sensory or motor blockade surgical time, block performance time, preoperative midazolam use, or intraoperative propofol use. CONCLUSION: Low volumes (30 mL or 20 mL) of 1.5% mepivacaine provides satisfactory anesthesia for ambulatory distal upper limb surgery with no significant difference in clinical outcomes.

Efficacy of Dacryoscintigraphy in Patients with Functional Block of Lacrimal Drainage System

To evaluate the diagnostic efficacy of dacryoscintigraphy, we examined Hones dye test and dacryoscintigraphy in 24 eyes of 18 patients who were suspected to have junctional block in lacrimal drainage system. Among 18 eyes that were negative to Jones I dye test, 3 showed punctal stenosis and 6 typical pattern of lax lid and 2 partial obsturction of nasolacrimal duct on dacryoscintigraphy. In evaluation of lacrimal drainage system, physiological aspect is as important as anatomical information since lacrimal pumping action of lid and tear flow as well as the patency of lacrimal passage contribute to the lacrimal drainage. Compared to Jones dye test, dacryoscintigraphy is more useful with certain advantages : It gives less discomfort to patients, provides anatomical information and does not depend on examiner`s skills.