Anthropometry of external auditory canal by non-contactable measurement.

Human ear canals cannot be measured directly with existing general measurement tools. Furthermore, general non-contact optical methods can only conduct simple peripheral measurements of the auricle and cannot obtain the internal ear canal shape-related measurement data. Therefore, this study uses the computed tomography (CT) technology to measure the geometric shape of the ear canal and the shape of the ear canal using a non-invasive method, and to complete the anthropometry of external auditory canal. The results of the study show that the average height and width of ear canal openings, and the average depth of the first bend for men are generally longer, wider and deeper than those for women. In addition, the difference between the height and width of the ear canal opening is about 40% (p < 0.05). Hence, the circular cross-section shape of the earplugs should be replaced with an elliptical cross-section shape during manufacturing for better fitting.

Counterion-activated nanoactuator: reversibly switchable killing/releasing bacteria on polycation brushes.

A strategy to release attached bacteria from surface-grafted bactericidal poly((trimethylamino)ethyl methacrylate chloride) (pTMAEMA) brushes has been proposed. The pTMAEMA brushes were fabricated via the surface-initiated atom transfer radical polymerization for contact killing of bacteria, including Escherichia coli, Staphylococcus epidermidis and Stenotrophomonas maltophilia. The bacteria-conditioning surfaces, afterward, were washed with electrolyte solutions containing anions with different lipophilic characteristic, charge density, polarity and adsorbility to quaternary ammonium groups in polymers. Because of the special ion-pairing interactions, the interfacial properties, including wettability and ζ-potential, can be manipulated in a controlled manner. Therefore, the counterion-assisted modulation of pTMAEMA brushes facilitates the bacterial release and regeneration of antimicrobial polymer films. The physicochemical properties of polymer brushes and their interactions with counterions were characterized using an ellipsometer, contact angle goniometer, X-ray photoelectron spectroscopy and an electrokinetic analyzer. The repetitive killing and releasing actions of pTMAEMA through unlocking and locking counterions were demonstrated, showing the robust effectiveness of the pTMAEMA-based nanoactuator in controlling the physical action by the chemical stimuli. The real-world implementation of the nanoactuator was demonstrated with a surgical scalpel by repelling killed bacteria and retaining reusability.

The curvature index and synchronization of dynamical systems.

We develop a quantity, named the curvature index, for dynamical systems. This index is defined as the limit of the average curvature of the trajectory during evolution, which measures the bending of the curve on an attractor. The curvature index has the ability to differentiate the topological change of an attractor, as its alterations exhibit the structural changes of a dynamical system. Thus, the curvature index may indicate thresholds of some synchronization regimes. The Rössler system and a time-delay system are simulated to demonstrate the effectiveness of the index, respectively.

Energy types of snoring sounds in patients with obstructive sleep apnea syndrome: a preliminary observation.

BACKGROUND: Annoying snore is the principle symptom and problem in obstructive sleep apnea syndrome (OSAS). However, investigation has been hampered by the complex snoring sound analyses. OBJECTIVE: This study was aimed to investigate the energy types of the full-night snoring sounds in patients with OSAS. PATIENTS AND METHOD: Twenty male OSAS patients underwent snoring sound recording throughout 6 hours of in-lab overnight polysomnogragphy. Snoring sounds were processed and analyzed by a new sound analytic program, named as Snore Map®. We transformed the 6-hour snoring sound power spectra into the energy spectrum and classified it as snore map type 1 (monosyllabic low-frequency snore), type 2 (duplex low-&mid-frequency snore), type 3 (duplex low- & high-frequency snore), and type 4 (triplex low-, mid-, & high-frequency snore). The interrator and test-retest reliabilities of snore map typing were assessed. The snore map types and their associations among demographic data, subjective snoring questionnaires, and polysomnographic parameters were explored. RESULTS: The interrator reliability of snore map typing were almost perfect (κ = 0.87) and the test-retest reliability was high (r = 0.71). The snore map type was proportional to the body mass index (r = 0.63, P = 0.003) and neck circumference (r = 0.52, P = 0.018). Snore map types were unrelated to subjective snoring questionnaire scores (All P>0.05). After adjustment for body mass index and neck circumference, snore map type 3-4 was significantly associated with severity of OSAS (r = 0.52, P = 0.026). CONCLUSIONS: Snore map typing of a full-night energy spectrum is feasible and reliable. The presence of a higher snore map type is a warning sign of severe OSAS and indicated priority OSAS management. Future studies are warranted to evaluate whether snore map type can be used to discriminate OSAS from primary snoring and whether it is affected by OSAS management.

Gain affected by the interior shape of the ear canal.

OBJECTIVE: This study investigated the correlation of gain distribution and the interior shape of the human external ear canal. STUDY DESIGN: Cross-sectional study of gain measurement at the first bend and second bend. SETTING: Chang Gung Memorial Hospital and Chang Gung University. SUBJECTS AND METHODS: There were 15 ears in patients aged between 20 and 30 years (8 men/7 women) with normal hearing and middle ears. Stimulus frequencies of 500, 1000, 2000, 3000, and 4000 Hz were based on the standard clinical hearing test. Measurements closer to the tympanic membrane and the positions at the first and second bends were confirmed by using otoscope. Real ear measurement to analyze the canal resonance in human external ears was adopted. RESULTS: This study found that gain at stimulus frequencies of 4000 Hz was affected by the interior shape of the ear canal (P < .005), particularly at the first and second bends, whereas gain was only affected by the length of the ear canal for stimulus frequencies of 2000 Hz (P < .005). CONCLUSION: This study found that gain was affected not only by the length of the external auditory canal (EAC) but also by the interior shape of the EAC significantly. The findings of this study may have potential clinical applications in canalplasty and congenital aural atresia surgery and may be used to guide surgeries that attempt to reshape the ear canal to achieve more desirable hearing outcomes.

Localized nasopharyngeal amyloidosis.

A mass in the nasopharynx often implies a malignancy in adults, particularly in the endemic areas of Epstein-Barr virus-associated undifferentiated carcinoma. We report an 86-year-old male patient who presented to our rhinologic outpatient department with postnasal drip for several years, with no other associated nasal symptoms. Physical examination with nasal endoscopy found a prominent bulge in the nasopharynx. Pathological examination of the biopsied specimens identified features consistent with amyloidosis. Magnetic resonance imaging demonstrated an enhanced soft-tissue mass localized to the nasopharyngeal region. We excluded the possibility of a partial representation of a potential systemic amyloidosis. Regular follow-up including nasal endoscopy was undertaken. Over 3 years of observation, the disease process remained silent. Here, the clinical presentation, diagnosis and treatment options of this rare entity are discussed.

Anti-control of chaos of single time-scale brushless DC motor.

Anti-control of chaos of single time-scale brushless DC motors is studied in this paper. In order to analyse a variety of periodic and chaotic phenomena, we employ several numerical techniques such as phase portraits, bifurcation diagrams and Lyapunov exponents. Anti-control of chaos can be achieved by adding an external constant term or an external periodic term.

Simple adaptive synchronization of chaotic systems with random components.

Practical systems usually possess random components. Random components often affect the robustness of synchronism and must be taken into consideration in the design of synchronization. In the present study, we assume that the system satisfies the Lipschitz condition, and the random component is uniformly bounded. By the partial stability theory, we are able to prove that two simple adaptive variable structure controllers achieve synchronization of chaotic systems. Moreover, we discuss how the controllers can be modified to eliminate the undesired phenomenon of chattering. The Duffing two-well system and the Chua circuit system are simulated to illustrate the theoretical analysis.