BackgroundTinnitus is a common condition and frequently can be annoying to affected individuals. We investigated the prevalence and associated factors for tinnitus in South Korea using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2009–2011.MethodsKNHANES is a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 21 893). A field survey team that included an otolaryngologist moved with a mobile examination unit and performed interviews and physical examinations.ResultsAmong the population over 12 years of age, the prevalence of any tinnitus was 19.7% (95% CI 18.8%–20.6%). Tinnitus was more prevalent in women, and the prevalence rate increased with age (P < 0.001). Among those with any tinnitus, 29.3% (95% CI 27.3%–31.3%) experienced annoying tinnitus that affected daily life. Annoying tinnitus also increased with age (P < 0.001), but no sex difference was demonstrated (P = 0.25). In participants aged 40 years or older, age, quality of life, depressive mood, hearing loss, feeling of dizziness, and rhinitis were associated with any tinnitus (P < 0.05). Age, hearing loss, history of cardiovascular disease, and stress were associated with annoying tinnitus (P < 0.05).ConclusionsTinnitus is a common condition, and a large population suffers from annoying tinnitus in South Korea. Public understanding of associated factors might contribute to better management of tinnitus.

Incisional pain dominated during the first two post-operative days after LC. Preoperative somato-visceral or somatic local anesthesia reduced incisional pain during the first three post-operative hours. A combination of somato-visceral local anesthetic treatment did not reduce intraabdominal pain, shoulder pain or nausea more than somatic treatment alone. Preoperative incisional infiltration of local anesthetics is recommended.

Background: Ketamine can enhance anesthetic and analgesic actions of a local anesthetic via a peripheral mechanism. The authors' goal was to determine whether or not ketamine added to ropivacaine in interscalene brachial plexus blockade prolongs postoperative analgesia. In addition, we wanted to determine the incidence of adverse-effects in patients undergoing hand surgery. Methods: Sixty adults scheduled for forearm or hand surgery under the interscalene brachial plexus block were prospectively randomized to receive one of the solutions of the study. Group P received 0.5% ropivacaine 30 ml, group K received 0.5% ropivacaine 30 ml with 30 mg ketamine, and group C received 0.5% ropivacaine with 30 mg ketamine i.v. Loss of shoulder abduction, elbow flexion, wrist flexion and loss of pinprick in the C4-7 sensory dermatomes were assessed at 1-min intervals. Adverseeffects were assessed every 5 min. The duration of the sensory and motor blocks was assessed after operation. Adverse-effects were also recorded. 821Results: The onset time of sensory or motor blockade and the duration of sensory or motor blockade were similar in all groups. Adverse-effects occurred in 44% of patients in group K and 94% of group C. Conclusion: This study suggests that 30 mg ketamine added to ropivacaine in the brachial plexus block does not improve the onset or duration of sensory block, but it does cause a relatively high incidence of adverse-effects. These two findings do not encourage the use of ketamine with local anesthetics for brachial plexus blockade.

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Background and ObjectivesInner ear symptoms like hearing loss, dizziness or tinnitus are often developed after head trauma, even in cases without inner ear destruction. This is also known as labyrinthine concussion. The purpose of this study is to determine the clinical manifestations, characteristics of audiometry and prognostic factors of these patients.Materials and MethodsWe reviewed the medical records of the 40 patients that had been diagnosed as labyrinthine concussion from 1996 to 2007. We studied the hearing levels in each frequency and classified them according to type and degree of hearing loss. Rates of hearing improvement were evaluated according to age, sex, hearing loss type, degree and presence of dizziness or tinnitus. To find out any correlation between hearing improvement and these factors, we used χ2 test or Fisher's exact test.ResultsBilateral hearing loss was observed in 22 patients, and unilateral hearing loss in 18 patients. There were 4 (6.5%) ascending, 34 (54.8%) descending, 24 (38.7%) flat type hearing loss, which indicated hearing loss was greater in high frequencies than low frequencies. Among 62 affected ears, 20 (32.3%) gained improvement, and it was achieved mainly in low frequencies. There were only 2 ears with dizziness in 20 improved ears and among 20 dizziness accompanied ears, also only 2 ears were improved.ConclusionsHigh frequencies are more vulnerable to trauma than low frequencies. The hearing gain is obtained mainly in low frequencies, and association with dizziness serves poor prognosis.

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Multiphase pumps are core equipment for offshore plant industry. They are utilized in diverse areas. According to a report about the tendency of multiphase pumps for offshore plant, a helico-axial pump is the most preferred. A helico-axial pump with advanced technologies is widely known to have large handling capacity and operability even at high GVF ranges. However, its disadvantage is that its mechanical efficiency is lower than other multiphase pumps. Because of this, a numerical optimization was performed in this study to enhance the hydraulic performance of multiphase pumps. Before numerical optimization, reliability verification of numerical analysis for single-phase and multiphase flow was carried out. To perform a single objective optimization for high efficiency, design variables and ranges were selected. The single objective optimization was conducted for both impeller and diffuser. The objective function was evaluated at design points using Latin-hypercube sampling, one experiment technique, in design ranges. The performance of the experiment sets was evaluated using advanced computational fluid dynamics. After that, the response surface of a second-order polynomial function which was produced based on the performance evaluation results was used to find the optimal point. The results showed remarkable increases in a higher performance level than the base model. The reason for performance improvement was analyzed through comparison of the internal flow field. Additionally, numerical results were compared to results of performance evaluation through experiment.

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