Is the 'safe zone' identified in preoperative computed tomography helpful for choosing optimal implant for fixation of radial head fracture?

The purpose of this study is to assess the clinical significance of the radiologic safe zone based on computed tomography and to compare the outcomes of three different implants for fixation of isolated radial head fractures. We retrospectively reviewed 367 patients who underwent internal fixation for isolated radial head fractures. We newly defined two subtypes of Mason type II fractures associated with the radiographic safe zone (IIA, two-part fracture allowing for safe fixation of plate; IIB, two-part fracture not allowing for safe fixation). 170 patients (CCS group, n = 82; HCS group, n = 31; plate group, n = 57) were investigated with no significant differences in demographics. The range of pronation and supination at 1 month postoperatively (P = 0.04 and P = 0.04) and the range of supination at 6 and 12 months postoperatively (P = 0.03 and P = 0.03) were significantly smaller in the plate group. In Mason type IIB fractures, the average MEPS was higher in the CCS and HSC groups than in the plate group (P = 0.01 and P = 0.02). And the average DASH score was lower in the CCS and HCS groups (P < 0.01 and P < 0.01). Evaluation of the radiologic safe zone is potentially helpful in selecting better surgical fixation option. For type III fractures, 2.3-mm cortical screws would be a better option than Acutrak screws. Plates would not be suitable for type IIB radial head fractures.

Increased risk of cardiovascular diseases in patients with chronic rhinosinusitis: a longitudinal follow-up study using a national health screening cohort.

BACKGROUND: Chronic rhinosinusitis (CRS) is one of the most common chronic inflammatory diseases and is characterized by sinonasal inflammation that lasts longer than 12 weeks. Whether the effect of chronic inflammation caused by CRS on cardiovascular diseases (CVDs) is similar to its effect on other inflammatory disorders has not been thoroughly evaluated. We aimed to demonstrate whether CRS patients have a higher prevalence of CVDs, including stroke and ischemic heart disease (IHD). METHODOLOGY: We compared the prevalence of various comorbidities between CRS and control participants through a case-control cohort study from 2002 to 2015 that included 514,866 participants. CRS (n=6,552) and control (n=26,208) participants who were over 40 years old were selected by matching age, sex, income, and area of residence at a 1:4 ratio. RESULTS: A stratified Cox proportional hazards model was utilized to assess the hazard ratio (HR) of CRS for stroke and IHD. The HRs for stroke and IHD were significantly increased in CRS patients compared to controls after adjusting for obesity, alcohol consumption, smoking, systolic and diastolic blood pressure, fasting blood glucose, total cholesterol, hemoglobin, and Charlson Comorbidity Index (CCI) scores. The HR of stroke was significantly higher in the absence of nasal polyps than in the presence of nasal polyps. The HR of IHD was significantly increased in the CRS group regardless of the presence of nasal polyps. CONCLUSIONS: This study showed that CRS participants had a significantly higher prevalence of stroke and IHD.

Association between air pollution and chronic rhinosinusitis: a nested case-control study using meteorological data and national health screening cohort data.

BACKGROUND: Inconsistent results about the effect of air pollution on chronic rhinosinusitis (CRS) have been reported. This study aimed to evaluate the impact of meteorological conditions/air pollution on the prevalence of CRS in adult Koreans. METHODOLOGY: The data from the Korean National Health Insurance Service-Health Screening Cohort from 2002 through 2015 were used. A CRS group (defined as ICD-10 codes J32, n=6159) was matched with a control group (n=24,636) in 1:4 ratios by age, sex, income, and region of residence. The meteorological conditions and air pollution data included the daily mean, highest, and lowest temperature (°C), daily temperature range (°C), relative humidity (%), ambient atmospheric pressure (hPa), sunshine duration (hr), and the rainfall (mm), SO2 (ppm), NO2 (ppm), O3 (ppm), CO (ppm), and PM10 (λg/m3) levels before the CRS diagnosis. Crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for CRS were analyzed using logistic regression analyses. RESULTS: When the NO2 level increased by 0.1 ppm, the odds for CRS increased 5.40 times, and when the CO level increased by 1 ppm and PM10 increased by 10 λg/m3, the odds for CRS decreased 0.75 times and 0.93 times, respectively. Other meteorological conditions, such as the mean/highest/lowest temperature, temperature range, rainfall and other air pollution, such as SO2 and O3, were not statistically significant. NO2 for 90 days before the index date increased the risk of CRS in all subgroups, except for the nasal polyp and older age subgroups. CONCLUSION: CRS is related to high concentrations of NO2.

Increased risk of chronic otitis media in chronic rhinosinusitis patients: a longitudinal follow-up study using a national health screening cohort.

BACKGROUND: Chronic rhinosinusitis (CRS) and chronic otitis media (COM) share pathophysiological mechanisms such as bacterial infection, biofilm, and persistence of the obstruction state of ventilation routes. However, only a few studies have investigated the relationship between these two diseases nationwide and in the general population. The purpose of this study was to determine whether the incidence of COM in patients with CRS differed from that of a matched control from the national health screening cohort. METHODS: Data from the Korean Health Insurance Review and Assessment Service-National Patient Samples were collected from 2002 to 2015. Participants who were treated ≥ ≥ ≥2 times and underwent head and neck computed tomography evaluation were selected. A 1:4 matched CRS group (n=8,057) and a control group (n=32,228) were selected. The control group included participants who were never treated with the ICD-10 code J32 from 2002 to 2015. The CRS group included CRS patients with/without nasal polyps. RESULTS: The incidence of COM was significantly higher in the CRS group than in the control group. In a subgroup analysis, the incidence of COM in all age groups and in men and women was significantly higher in the CRS group than in the control group. More, CRS increased the risk of COM. CONCLUSIONS: A significant association was observed between CRS and COM. This indicates that CRS patients have a high risk of developing COM.

High-Intensity Physical Activity with High Serum Vitamin D Levels is Associated with a Low Prevalence of Osteopenia and Osteoporosis: A Population-Based Study.

We found that combination of high-intensity PA and high 25(OH)D levels was associated with low prevalence of osteoporosis/osteopenia. In addition, the prevalence of osteoporosis was lower in the low PA with high 25(OH)D levels than in the moderate or high PA with low 25(OH)D levels. INTRODUCTION: The aim of this study was to explore the association of physical activity (PA) and serum 25-hydroxyvitamin D (25[OH]D) levels with osteopenia/osteoporosis. METHODS: The Korean National Health and Nutrition Examination Survey data from 2008 to 2011 were used in this study. Data from 6868 individuals were selected. Each individual's level of PA was classified as 'low', 'moderate', or 'high'. Serum 25(OH)D levels were classified as 'low' or 'high'. Accordingly, the combined PA and 25(OH)D groups were divided into 6 groups. Bone mineral density (BMD) was classified as 'normal (T score ≥ - 1.0)', 'osteopenia (- 2.5 < T score < - 1.0)' or 'osteoporosis (T score ≤ - 2.5)'. Crude and adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were calculated using multinomial logistic regression models. RESULTS: The AORs (95% CIs) for osteopenia were 0.64 (0.50-0.83) in the high PA with high 25(OH)D group and 0.69 (0.53-0.88) in the moderate PA with high 25(OH)D group. The AORs (95% CIs) for osteoporosis were increased in the groups in ascending order as follows: high PA with high 25(OH)D (0.40 [0.28-0.57]) < moderate PA with high 25(OH)D (0.47 [0.33-0.66]) < low PA with high 25(OH)D (0.59 [0.42-0.83]) < high PA with low 25(OH)D (0.70 [0.49-1.00]) < moderate PA with low 25(OH)D (0.76 [0.53-1.07]) < low PA with low 25(OH)D. This result was consistent in males but not evident in females. CONCLUSION: We suggest that the combination of high-intensity PA and high 25(OH)D levels is positively associated with high BMD.

Psoriasis is associated with an increased risk of osteoporosis: follow-up and nested case-control studies using a national sample cohort.

A total of 25,306 psoriasis participants were matched to 101,224 controls, and the occurrence of osteoporosis was analyzed. Additionally, 79,212 osteoporosis patients were matched to 79,212 controls and a previous history of psoriasis was analyzed. Psoriasis increased the risk of osteoporosis among participants aged ≥ 40 years. INTRODUCTION: The aim of the present study was to evaluate the association between psoriasis and osteoporosis using two different studies. METHODS: Data from the Korean National Health Insurance Service-Health Screening Cohort of participants aged ≥ 40 years were collected from 2002 to 2013. Psoriasis and osteoporosis were included using International Classification of Diseases (ICD)-10 codes. In study I (a follow-up study), a total of 25,306 psoriasis participants were matched to 101,224 controls with respect to age, sex, income, and region of residence, and the occurrence of osteoporosis was analyzed. Crude (simple) and adjusted hazard ratios (HRs) were analyzed using a stratified Cox proportional hazard model. In study II (a nested case-control study), a total of 79,212 osteoporosis patients were matched to 79,212 controls and a previous history of psoriasis was analyzed. Crude and adjusted odds ratios (ORs) were analyzed using a conditional logistic regression analysis. Subgroup analyses were conducted according to age group and sex. RESULTS: The adjusted HR of osteoporosis was 1.09 (95% confidence interval [CI] = 1.05-1.13, P < 0.001) in study I. In the subgroup analysis according to age and sex, the results were consistent except for ≥ 60-year-old women. The adjusted OR of psoriasis was 1.21 (95% CI = 1.16-1.27, P < 0.001) in study II. All subgroups demonstrated high adjusted ORs of osteoporosis for psoriasis. CONCLUSIONS: Psoriasis increased the risk of osteoporosis among participants aged ≥ 40 years in Korea.

Chronic rhinosinusitis and progression of cognitive impairment in dementia.

AIM: The relationship between chronic inflammatory disease and cognitive decline is still unclear, but there is increasing evidence to support the role of systemic inflammation. The aim of this study was to investigate if chronic rhinosinusitis (CRS) in dementia or mild cognitive impairment (MCI) is associated with the progression of cognitive decline. MATERIAL AND METHODS: We retrospectively reviewed the data of patients who complained of memory impairment, and underwent brain magnetic resonance imaging (MRI) from January 2006 to April 2019. According to the Mini-Mental State Examination (MMSE) score, subjects (n=661) were divided into three groups: dementia (≤17), MCI (18-23), and normal (≥24). CRS was defined as a total score of greater than or equal to 4 according to the Lund-Mackay scoring system using brain MRI. Multiple logistic regression analyses estimated adjusted odds ratio (aOR) for the association between CRS and dementia or MCI. Among the subjects with follow-up MMSE (n=286), a repeated-measures ANOVA was used to assess the difference of changes in MMSE scores between the groups with and without CRS. RESULTS: According to the initial MMSE score, there were 221 subjects with dementia, 195 with MCI, and 245 with normal results. CRS was not significantly associated with dementia (aOR=1.519, CI=0.909-2.538, P=0.111), while being suggestively associated with MCI (aOR=1.740, CI=1.041-2.906, P=0.034). The MMSE scores at follow-up decreased further in subjects with CRS than in those without CRS (P=0.009). Especially, in the initial dementia group, there was a significant between-group difference in the MMSE score from baseline to follow-up (13.6±4.3 to 11.1±6.3 in CRS group vs. 13.5±3.3 to 14.4±5.4 in no CRS group, P=0.002). CONCLUSION: The result of the present study implies a potential association between CRS and progression of cognitive decline. Physicians should be aware of this possibility in patients with clinically diagnosed CRS.

Blindness increases the risk for hip fracture and vertebral fracture but not the risk for distal radius fracture: a longitudinal follow-up study using a national sample cohort.

The risks for hip fracture and vertebral fracture, but not the risk for distal radius fracture, were significantly higher in the blindness group than in the control group with a maximum 12-year follow-up. PURPOSE: To evaluate the influence of visual impairment on the risk for osteoporotic fractures at common sites: hip, thoracic/lumbar vertebra, and distal radius. METHODS: This longitudinal follow-up study used a database of a national sample cohort from 2002 to 2013 provided by the Korean National Health Insurance Service. Of a total of 1,125,691 subjects, 3918 patients with visual impairment and age ≥ 50 years were enrolled in a 1:4 ratio; 15,672 control participants were matched for age, sex, income, and region of residence. Stratified Cox proportional-hazards models were used to evaluate the crude and adjusted (for steroid medication, rheumatoid arthritis, depression, osteoporosis, diabetes mellitus, and stroke history) hazard ratios (HRs) for each fracture site. Fracture diagnoses were based on the ICD-10 codes: hip fracture (S720, S721, S722), vertebral fracture (S220, S320), and distal radius fracture (S525). RESULTS: The HRs for hip and vertebral fracture were significantly higher in the blindness group (adjusted HR = 2.46, p < 0.001 for hip fracture; adjusted HR = 1.42, p = 0.020 for thoracic/lumbar vertebral fracture) than in the matched control group. However, the HR for distal radius fracture was not higher in the blindness group. The HRs for all three fracture sites were not significantly higher in the non-blindness visual impairment group after adjustment. CONCLUSION: The risks for hip fracture and vertebral fracture were significantly higher in the blindness group. However, the risk for distal radius fracture was not related to visual impairment including blindness.

Association between benign paroxysmal positional vertigo and osteoporosis: two nested case-control studies.

Benign paroxysmal positional vertigo (BPPV) was related to a 1.28 times higher risk of osteoporosis. In addition, osteoporosis was associated with a 1.34 times higher risk of BPPV. This bidirectional relation was maintained after adjusting past medical histories and lifestyle factors, including obesity, smoking, and alcohol consumption. To our knowledge, this is the first study to explore the reciprocal association between BPPV and osteoporosis. In subgroup analyses, only women showed a reciprocal association between BPPV and osteoporosis. INTRODUCTION: A previous population cohort study suggested an association between osteoporosis and benign paroxysmal positional vertigo (BPPV). This study aimed to investigate the bidirectional association between BPPV and osteoporosis. METHODS: The Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2013 were used. In study I, the 50,897 osteoporosis patients were 1:1 matched with control I participants for age, sex, income, and region of residence. The previous histories of BPPV were analyzed in both groups using conditional logistic regression analysis. In study II, 9621 BPPV patients were 1:4 matched with control II participants. The previous histories of osteoporosis were analyzed in both groups using conditional logistic regression analysis. According to age and sex, subgroup analyses were achieved in both studies I and II. RESULTS: A total of 1.6% (822/50,897) of osteoporosis patients and 1.3% (644/50,897) of control I participants had BPPV. The osteoporosis patients demonstrated a 1.28 times higher chance of developing BPPV (95% confidence intervals [95% CI] = 1.16-1.42, P < 0.001). In study II, 21.2% (2040/9621) of BPPV patients and 17.6% (6790/38,484) of control II participants had osteoporosis. The BPPV patients showed 1.34 times higher chance of having osteoporosis (95% CI = 1.26-1.43, P < 0.001). In the analysis of the women subgroup, these relations were reliable. CONCLUSION: Osteoporosis patients had increased odds of having BPPV. On the other hand, BPPV patients had increased odds of having osteoporosis. This bidirectional relation was consistent only in the women subgroup.

Dietary modification for laryngopharyngeal reflux: systematic review.

OBJECTIVE: This study aimed to determine the relationship between laryngopharyngeal reflux and dietary modification. METHODS: A systematic review was conducted. The data sources for the study were PubMed, Embase, Cochrane Library and Web of Science. Articles were independently extracted by two authors according to inclusion and exclusion criteria. The outcome focus was laryngopharyngeal reflux improvement through diet or dietary behaviour. RESULTS: Of the 372 studies identified, 7 met our inclusion criteria. In these seven studies, laryngopharyngeal reflux symptoms improved following dietary modifications. However, the studies did not present the independent effect of each dietary factor on laryngopharyngeal reflux. Moreover, only one of the seven studies had a randomised controlled study design. CONCLUSION: The reference studies of dietary modification for laryngopharyngeal reflux patients are not sufficient to provide recommendations.

Mortality and cause of death postoperatively in patients with a hip fracture: a national cohort longitudinal follow-up study.

Aims: The aim of this study was to compare the rate of mortality and causes of death in Korean patients who undergo surgery for a fracture of the hip, up to 11 years after the injury, with a control group from the general population. Materials and Methods: National cohort data from Korean Health Insurance Review and Assessment Service - National Sample Cohort were used. A ratio of 1:4 matched patients with a fracture who underwent surgery (3383, fracture group) between 2003 and 2012, and controls (13 532) were included. The matches were processed for age, gender, income, and region of residence. We also undertook analyses of subgroups according to age and gender. The mean follow-up was 4.45 years (1 to 11). Results: The prevalence of hypertension, diabetes, and stroke was significantly higher in the fracture group and dyslipidemia in the controls. Both crude and adjusted hazard ratios (HR) for the rate of mortality in the fracture group were > 2 (crude HR 2.03, 95% confidence interval (CI) 1.91 to 2.17, p < 0.001; adjusted HR 2.07, 95% CI 1.94 to 2.21, p < 0.001). The HRs were also > 2 for both men and women, and for both those aged ≥ 50 years and < 50 years. However, for those aged < 50 years, they were insignificant. The rates of mortality due to all 11 major causes of death classified following Korean standard classification of diseases were significantly higher in the fracture group compared with the control group, except those in the mental and behavioral disorders category. Conclusion: The rate of mortality in the fracture group was significantly higher than in the control group up to 11 years after the surgery. The rate of death due to almost every major cause was significantly higher in the fracture group compared with the control group. Cite this article: Bone Joint J 2018;100-B:436-42.

Analysis of ingested foreign bodies according to age, type and location: a retrospective observational study.

OBJECTIVE: This study aimed to analyse the types and locations of ingested foreign bodies according to different age groups, from infants to the elderly. DESIGN: A retrospective chart review. SETTING: Tertiary referral centre. PARTICIPANTS: A total of 4682 patients who ingested foreign bodies from January 2006 through February 2014. METHODS: The frequencies of foreign bodies were investigated in each age group. The types of foreign bodies were categorised into fish bones, chicken bones, seafood, tablets, food, metal, batteries, glass, teeth, plastics and others. The anatomic locations of the objects were classified as the oral cavity, tongue base, tonsils, oropharynx, hypopharynx, oesophagus, stomach and colon. The types, locations and origins of the foreign bodies were analysed according to the age groups. RESULTS: The frequency of foreign body ingestion was high in patients up to 14 years of age, after which the risk of foreign body ingestion markedly decreased. Fish bones were the most commonly suspected foreign bodies in all of the age groups. However, non-food-type foreign bodies were more common in both the young and elderly groups. The tonsils were the most common anatomic site of foreign body impaction except in the group of patients older than 65 years. The stomach and oesophagus were also common locations of foreign bodies in the groups of patients younger than 10 years (10.5%) and older than 65 years (39.4%). CONCLUSION: The frequency of foreign body ingestion was highest in young children. However, we observed specific age-based characteristics that indicate specific precautions to take to avoid foreign body ingestion.

Comparison of positive end-expiratory pressure-induced increase in central venous pressure and passive leg raising to predict fluid responsiveness in patients with atrial fibrillation.

BACKGROUND: Positive end-expiratory pressure (PEEP)-induced increase in central venous pressure (CVP) has been suggested to be a robust indicator of fluid responsiveness, with heart rhythm having minimal influence. We compared the ability of PEEP-induced changes in CVP with passive leg raising (PLR)-induced changes in stroke volume index (SVI) in patients with atrial fibrillation after valvular heart surgery. METHODS: In 43 patients with atrial fibrillation after cardiac surgery, PEEP was increased from 0 to 10 cm H2O for 5 min and changes in CVP were assessed. After returning the PEEP to 0 cm H2O, PLR was performed for 5 min and changes in SVI were recorded. Finally, 300 ml of colloid was infused and haemodynamic variables were assessed 5 min after completion of a fluid challenge. Fluid responsiveness was defined as an increase in SVI ≥10% measured by a pulmonary artery catheter. RESULTS: Fifteen (35%) patients were fluid responders. There was no correlation between PEEP-induced increases in CVP and changes in SVI after a fluid challenge (ß coefficient -0.052, P=0.740), whereas changes in SVI during PLR showed a significant correlation (ß coefficient 0.713, P<0.001). The area under the receiver operating characteristic curve of the PEEP-induced increase in CVP and changes in SVI during PLR for fluid responsiveness was 0.556 [95% confidence interval (CI) 0.358-0.753, P=0.549) and 0.771 (95% CI 0.619-0.924, P=0.004), respectively. CONCLUSIONS: A PEEP-induced increase in CVP did not predict fluid responsiveness in patients with atrial fibrillation after cardiac surgery, but increases in SVI during PLR seem to be a valid predictor of fluid responsiveness in this subset of patients.

Crosstalk analysis in homogeneous multi-core two-mode fiber under bent condition.

We analyze the inter-core crosstalk in homogeneous multi-core two-mode fibers (MC-TMFs) under bent condition by using the coupled-mode equations. In particular, we investigate the effects of the intra-core mode coupling on the inter-core crosstalk for two different types of MC-TMFs at various bending radii. The results show that the inter-core homo-mode crosstalk of LP(11) mode is dominant under the gentle fiber bending condition due to its large effective area. However, as the fiber bending becomes tight, the intra-core mode coupling is significantly enhanced and consequently makes all the inter-core crosstalk levels comparable to each other regardless of the mode. A similar tendency is observed at a reduced bending radius when the difference in the propagation constants between modes is large and core pitch is small.

Engineering of a lipid-polymer nanoarchitectural platform for highly effective combination therapy of doxorubicin and irinotecan.

We developed a highly stable lipid-polymer nanoarchitectural platform for effective combination therapy of doxorubicin and irinotecan in the polyelectrolyte complex nanoparticle core, followed by incorporation of the whole assembly into a lecithin bilayer. It shows great potential for the treatment of a broad range of cancers.

Efficacy and safety of topical glycopyrrolate in patients with facial hyperhidrosis: a randomized, multicentre, double-blinded, placebo-controlled, split-face study.

BACKGROUND: Although facial hyperhidrosis has been frequently associated with a diminished quality of life, various conservative modalities for its management are still far from satisfactory. OBJECTIVE: To evaluate the antiperspirant efficacy and safety of the topical glycopyrrolate on facial hyperhidrosis at specified posttreatment intervals. METHODS: Thirty-nine patients with facial hyperhidrosis were enrolled and treated with 2% topical glycopyrrolate on one-half of the forehead, whereas the other half of the forehead was treated with a placebo. All patients applied topical glycopyrrolate or placebo once a day for nine successive days. Each evaluation included weighing sweat and assessing the Hyperhidrosis Disease Severity Scale (HDSS) score and any adverse effects. RESULTS: Compared with the placebo-treated sides, topical glycopyrrolate-treated sides showed a reduction in the rate of sweat production at the forehead of 25.16 ± 10.30% (mean ± SD) at 90 min after the first application (day 1), 29.63 ± 7.74% at 24 h after the first application (day 2) and 36.68 ± 11.41% at 24 h after eight additional successive daily applications (day 10) (all P < 0.025). There was a little more decrease in HDSS score with the topical glycopyrrolate-treated half of the forehead, but the difference was not statistically significant (P > 0.025). No serious adverse events were reported during the course of this study. Only one patient developed a transient headache after treatment. CONCLUSION: Topical glycopyrrolate application appears to be significantly effective and safe in reducing excessive facial perspiration.

Optical performance monitoring technique using software-based synchronous amplitude histograms.

We propose and demonstrate a simple technique to monitor both the optical signal-to-noise ratio (OSNR) and chromatic dispersion (CD) by using the software-based synchronous amplitude histogram (SAH) analysis. We exploit the software-based synchronization technique to construct SAHs from the asynchronously sampled intensities of the signal. The use of SAHs facilitates the accurate extraction of the monitoring parameters at the center of the symbol. Thus, unlike in the case of using the technique based on the asynchronous amplitude histogram (AAH), this technique is not affected by the transient characteristics of the modulated signals. The performance of the proposed monitoring technique is evaluated experimentally by using 10-Gbaud quadrature phase-shift keying (QPSK) and quadrature amplitude modulation (QAM) signals over wide ranges of OSNR and CD. We also evaluate the robustness of the proposed technique to the signal's transient characteristics.

Simple carrier-phase estimator for high-speed RSOA-based coherent WDM PON.

It has been recently reported that reflective semiconductor optical amplifiers (RSOAs) can be used as phase modulators for the cost-effective implementation of the high-speed wavelength-division-multiplexed passive optical networks (WDM PONs). For the detection of the phase-shift-keying (PSK) signal generated by using an RSOA, we should be able to estimate its carrier phase accurately at the digital coherent receiver. However, when the baud rate of this PSK signal is set to be much higher than the RSOA's modulation bandwidth, the conventional M-th power algorithm cannot estimate its carrier phase accurately. To solve this problem, we develop a simple carrier-phase estimation technique for the high-speed (>10 Gb/s) PSK signals generated by using bandwidth-limited RSOAs. This technique estimates the carrier phase of the PSK signal by measuring the angular direction of the opening occurred in the trajectory of the phasor diagram. By using the proposed technique, we demonstrate the upstream transmission of the 25.78-Gb/s quadrature phase-shift-keying (QPSK) signal generated by using an RSOA (3-dB bandwidth: 3.2 GHz) in a 60-km reach coherent WDM PON.

Achievable capacity improvement by using multi-level modulation format in trench-assisted multi-core fiber system.

We evaluate the impacts of using multi-level modulation formats on the transmission capacity of the multi-core fiber (MCF) having trench-assisted index profile and hexagonal layout. For this evaluation, we utilize the spectral efficiency per unit area, defined as the spatial spectral efficiency (SSE). The results show that the SSE improvement achievable by using the higher-level modulation format can be reduced due to its lower tolerance to the inter-core crosstalk. We also evaluate the effects of using large effective area on the transmission capacity of the trench-assisted MCF. The results show that the use of large effective area can decrease this capacity due to the increased inter-core crosstalk and lengthened cable cutoff wavelength, although it can help increase the transmission distance. Thus, it is necessary to optimize the effective area of MCF by considering both the SSE and transmission distance. However, the results indicate that the effect of using different effective areas on the SSE-distance product is not significant, and it is not useful to increase the effective area of the trench-assisted MCF to be larger than ~110 µm(2).

Clinical characteristics and audiological significance of spontaneous otoacoustic emissions in tinnitus patients with normal hearing.

OBJECTIVE: To define the clinical and audiological features of normal-hearing tinnitus patients with spontaneous otoacoustic emissions, and to evaluate the role of spontaneous otoacoustic emissions in tinnitus generation. MATERIALS AND METHODS: Thirty-two patients with spontaneous otoacoustic emissions were compared with 29 patients without spontaneous otoacoustic emissions, regarding clinical and audiological aspects. RESULTS: The mean age of the study group subjects was significantly lower, and they experienced the kindling effect less frequently than the control group. The mean tinnitus handicap inventory score of the study group was considerably higher than that of the controls, although the difference was not statistically significant. The study group had significantly quieter tinnitus, and higher transient evoked and distortion product otoacoustic emission responses, compared with the control group. CONCLUSIONS: Normal-hearing tinnitus patients with spontaneous otoacoustic emissions have different clinical and audiological characteristics, compared with those without spontaneous otoacoustic emissions. Appropriate evaluation and treatment should be considered at an early stage in these patients.