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The superior chemical and electrical properties of TiO

Silicon nanowires (SiNWs) are promising structures with excellent photovoltaic properties for low-cost, high-efficiency solar cells and have the potential to overcome the limits of bulk silicon solar cells. There is still a need to enhance light absorption in SiNWs without increasing the surface area. Here, we introduce a novel design, hourglass-shaped silicon nanowire (HG-SiNW) to significantly increase the light-trapping path. Electrical and optical measurements show the superiority of HG-SiNW as an antireflective layer. In addition, whispering gallery mode identified by optical simulations accounts for the greatly improved absorption at the broadband solar spectrum. The HG-SiNW solar cells show an increase in short-circuit current ( J SC) and 1.85 times higher efficiency with only simple diameter variations.

For the removal of pollutants, a modified TiO2 photocatalyst is attracting attention. Fe-doped TiO2 nanofibers were prepared through a combination of electrospinning and calcination. Morphological characterization of the sample was conducted using field-emission scanning electron and transmission electron microscopy. The crystal structure of each sample was analyzed using high-resolution transmission electron microscopy, selected area electron diffraction, and Fast Fourier Transform imaging. The average diameter of the Fe-doped TiO2 nanofibers was measured to be 161.5 nm and that of the pure TiO2 nanofibers was 181.5 nm. The crystal phase when heat treated at 350 °C was anatase for TiO2 nanofibers and rutile for Fe-doped TiO2 nanofibers. The crystal phase of the TiO2 matrix was easily transitioned to rutile by Fe-doping. The photocatalytic performance of each sample was compared via the photodegradation of methylene blue and acid orange 7 under ultraviolet and visible light irradiation. In the Fe-doped TiO2 nanofibers, photodegradation rates of 38.3% and 27.9% were measured under UV irradiation and visible light, respectively. Although other catalysts were not activated, the photodegradation rate in the Fe-doped TiO2 nanofibers was 9.6% using acid orange 7 and visible light. For improved photocatalytic activity, it is necessary to study the concentration control of the Fe dopant.

Silicon photodiodes are widely used in applications that require the measurement of the intensity, colour and position of visible light. Silicon is an attractive material for these systems owing to its low cost, low noise, and easy on-chip integration with read-out electronics. However, silicon cannot effectively be used to detect near-infrared (NIR, at wavelengths of 700–1,000 nm) light and short-wave infrared (SWIR, 1,000–1,700 nm) light because of its bandgap of 1.12 eV, which is equivalent to a wavelength of 1,100 nm. Here, we report silicon photodiodes based on hourglass-shaped silicon nanowires that use whispering-gallery-mode resonances to enhance their photoresponse in the NIR–SWIR region of the spectrum. The upper, inverted nanocone of the nanowires increases absorption probability by extending the dwell time of NIR–SWIR photons via the generation of whispering-gallery-mode resonances, whereas the lower nanocone with its low reflectance reabsorbs the light incident from surrounding nanowires. Our devices exhibit a higher responsivity and external quantum efficiency than existing silicon photodiodes at 700–1,100 nm. Furthermore, the responsivity at 1,000 nm is similar to that of commercial InGaAs photodiodes and light at 1,400 nm can also be detected. Using our devices, we demonstrate a heart-rate measurement system that offers performance comparable to commercial setups. The absorption profile of photodetectors based on silicon can be extended into the near- and shortwave-infrared regions by taking advantage of optical resonance effects.

A silicon-based laser is a critical component in the realization of full silicon (Si) photonic integrated circuits due to advantages in cost-competitive integration with the mature digital technolo...

Tuning geometrical parameters of lithium-mixed transition-metal oxide (LiTM) cathode materials is a promising strategy for resource-efficient design of high-performance Li-ion batteries. In this paper, we demonstrate that simple and facile geometrical tailoring of the secondary microstructure of LiTM cathode materials without complex chemical modification or heterostructure engineering can significantly improve overall electrochemical performance of the active cathode materials. An optimized LiTM with a bimodal size distribution of primary particles inside the secondary particles exhibits a 53.8% increase in capacity at a high discharge rate (10 C) compared to a commercially available reference and comparable rate capability after 100 charge/discharge cycles. The key concept of this approach is to maximize the beneficial effects arising from the controlled sizes of primary particles. Multimodal/multiscale microscopic characterizations based on electron tomography and scanning transmission electron microscopy, combined with electron energy-loss spectroscopy and energy-dispersive X-ray spectroscopy from the atomic level to the microscale level, were employed to elucidate structural origins of enhanced battery performance. This study paves the way for the resource-efficient microstructure design of LiTM cathode materials to maximize capacity and stability via simple adjustment of processing conditions, which is advantageous for mass-production applications.

For the removal of pollutants, a modified TiO2 photocatalyst is attracting attention. Fe-doped TiO2 nanofibers were prepared through a combination of electrospinning and calcination. Morphological characterization of the sample was conducted using field-emission scanning electron and transmission electron microscopy. The crystal structure of each sample was analyzed using high-resolution transmission electron microscopy, selected area electron diffraction, and Fast Fourier Transform imaging. The average diameter of the Fe-doped TiO2 nanofibers was measured to be 161.5 nm and that of the pure TiO2 nanofibers was 181.5 nm. The crystal phase when heat treated at 350 °C was anatase for TiO2 nanofibers and rutile for Fe-doped TiO2 nanofibers. The crystal phase of the TiO2 matrix was easily transitioned to rutile by Fe-doping. The photocatalytic performance of each sample was compared via the photodegradation of methylene blue and acid orange 7 under ultraviolet and visible light irradiation. In the Fe-doped TiO2 nanofibers, photodegradation rates of 38.3% and 27.9% were measured under UV irradiation and visible light, respectively. Although other catalysts were not activated, the photodegradation rate in the Fe-doped TiO2 nanofibers was 9.6% using acid orange 7 and visible light. For improved photocatalytic activity, it is necessary to study the concentration control of the Fe dopant.

The core-shell silicon nanowire photodetector has been reported with enhanced responsivity. The interface traps play critical role to determine the performance of core-shell photodetector. The effect of interface quality on the photo response has been investigated using crystalline silicon and polysilicon shells. The device with single-crystalline silicon shell exhibits higher responsivity than that with polysilicon shell. The performance degradation of polysilicon device is caused by the grain boundaries, which are defect sources. Based on these results, the single-crystalline silicon shell was used for fabricating core-shell silicon nanowire photodetector. The photodetector exhibits the maximum responsivity of 0.51 A/W, which is 10% higher than the planar photodetector. Consequently, the core-shell homogeneous silicon nanowire structure can be a promising component for photodetector application.

The objective of this study was to examine the feasibility and sustained effect of a group aerobic exercise program in patients with schizophrenia. Twenty-four schizophrenic patients participated in a group-based individually tailored 90-minute outdoor cycling session per week for 3 months with intervention to enhance motivation. Physical health was evaluated by anthropometric measures, cardiorespiratory (CR) fitness, and blood tests. Mental health was assessed on self-esteem, interpersonal relationship, quality of life, and global function. Attrition rate for the exercise program was 8.3%. Exercise program significantly increased participant's self-esteem, positive relationship, global function, and quality of life. CR fitness significantly improved after 3 months. At the 9-month follow-up, 6 months after program completion, only in interpersonal relationship change the improved effects were maintained. These findings support the feasibility of group aerobic exercise program with high level of adherence and its long-term benefits in positive relationship change.

Silicon nanowires (SiNWs) have attracted attention as promising high efficiency thermoelectric materials by significantly improving the thermoelectric efficiency of silicon. Here, we have fabricated cobalt silicide/silicon heterostructure on both ends of nanowires using self-aligned silicide (salicide) process. By forming cobalt silicide (CoSi2) layer on SiNWs, the thermal conductivity of SiNWs with diameters of 200, 350, and 500 nm decrease to 25.1, 31.3, and 38.1 W·m−1·K−1, respectively, which is about 8% reduction on average. Since the phonon nanoinclusion scattering is influenced by the density of the nanoinclusions, the thermal conductivity tends to decrease as the volume fraction of CoSi2 in SiNWs increases. The Seebeck coefficient of the heterostructured nanowires increases to 255 μV/K, which is mainly attributed to the low-energy charge carrier filtering effect due to the Schottky barrier at the CoSi2/Si interfaces. The measurements show that the figure-of-merit ZT of the heterostructured nanowires is improved by 10% on average compared with the conventional SiNWs. Consequently, the CoSi2/Si heterostructured nanowires enhance the thermoelectric properties of SiNWs effectively by suppressing phonon transport and improving electron flow.

Purpose: To determine the role of metabolic syndrome (MetS) as a risk factor for acquired premature ejaculation (PE) after considering the various risk factors, such as lower urinary tract symptoms, erectile dysfunction, hypogonadism, and prostatitis. Materials and Methods: From January 2012 to January 2017, records of 1,029 men were analyzed. We performed multivari-ate analysis to identify risk factors for PE, including the covariate of age, marital status, International Prostate Symptom Score, International Index of Erectile Function (IIEF) score, National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI) score, serum testosterone levels, and all components of MetS. Acquired PE was defined as self-reported intravaginal ejacula-tion latency time ≤3 minutes, and MetS was diagnosed using the modified National Cholesterol Education Program Adult Treatment Panel III criteria. Results: Of 1,029 men, 74 subjects (7.2%) had acquired PE and 111 (10.8%) had MetS. Multivariate analysis showed that the IIEF overall satisfaction score (odds ratio [OR]=0.67, p

Objective Early treatment choice is critical in first-episode schizophrenia-spectrum disorders. The purpose of this study was to describe prescribing trends of antipsychotics use in patients with first-episode schizophrenia in 2005 and 2010, respectively. Methods We reviewed the medical records of newly treated patients with schizophrenia from a university psychiatric hospital in 2005 (n=47) and 2010 (n=52). We defined patients as receiving a high antipsychotic dose if their ratio of prescribed daily dose (PDD) to defined daily dose (DDD) was greater than 1.5. Results The rates of high-dose antipsychotic prescription were 61.7% and 53.8% in 2005 and 2010, respectively. The rates of antipsychotic polypharmacy were 34.6% in 2005 and 34.0% in 2010. The most common first-prescribed antipsychotics were (in descending order of prescription frequency) olanzapine, risperidone, aripiprazole, and haloperidol in 2005 and risperidone, quetiapine, paliperidone, and olanzapine in 2010. High-dose antipsychotics were significantly associated with antipsychotic poly-pharmacy (odds ratio=23.97; p

Purpose: This study aimed to investigate the relationships between body mass index (BMI) and prostate-specific antigen (PSA) levels, international prostate symptom score (IPSS), quality of life (QoL), and prostate volume (PV). Materials and Methods: Height, weight, PSA levels, PV, and IPSS were analyzed in 15,435 patients who underwent a prostate examination between 2001 and 2014. Patients aged ＜50 years or with a PSA level ≥10 ng/mL were excluded. The relationships between BMI and PSA, IPSS, QoL, and PV were analyzed by a scatter plot, one-way analysis of variance, and the Pearson correlation coefficient. Results: The mean age was 71.95±7.63 years, the mean BMI was 23.59±3.08 kg/m2, the mean PSA level was 1.45±1.45 ng/mL, the mean IPSS was 15.53±8.31, the mean QoL score was 3.48±1.25, and the mean PV was 29.72±14.02 mL. PSA, IPSS, and QoL showed a tendency to decrease with increasing BMI, and there were statistically significant differences for each parameter (p≤0.001). PV showed a significant tendency to increase with BMI (p＜0.001). In the correlation analysis, BMI showed a statistically significant correlation (p＜0.001) with PSA, IPSS, and QoL, although the correlations were very weak. In contrast, BMI showed a significant correlation with PV (p＜0.001), with a meaningful Pearson correlation coefficient of 0.124. Conclusions: Higher BMI was associated with lower PSA levels and higher IPSS and QoL scores. Meanwhile, PV increased with BMI. Although obese individuals had a greater PV, obesity did not aggravate lower urinary tract symptoms.

The impedance cardiogram has been proposed as a non-invasive, continuous, operator independent, and cost-effective method for cardiac output monitoring. However, it can not be completely considered as non-restrictive method because of attached spot and band type electrodes. Therefore, we developed a improved convenient hand-held typed measurement system for cardiac output by electrical impedance technique. 80 subjects from Yonsei University and the surrounding areas, participated. All subjects measured stroke volume and cardiac output through Physioflow and developed system. To verify the developed system, statistical methods such as correlation, Wilcoxon signed ranks test, and the Bland-Altman analysis were used. The proposed system showed significant correlation in both male and female stroke volume(r

In this study, a new method that can estimate ICG data from a subject`s both hands to measure Cardiac Output under convenient sensor environment. With this aim, a grip-type electrode was implemented to measure ICG. To improve the accuracy of measurement, the regression equation was extracted using multiple bio-parameters and our result was compared with the thoracic ICG equipment(Physio Flow, PF104D, Manatec Biomedical, France), which is being used in clinics. The subjects consist of 26 men and 4 women(age in ). They are no cardiac disease. Parameters available for regression model were used gender, BMI, MBP, LVET, dZ/dt(max), distance between the measured electrodes, body impedance, and PTT. As a result of analyzing the ICG measurement value on thorax and both hands, the correlation with stroke volume, heart rate, and cardiac output was

The blood pressure measuring equipment, which is being supplied and used most widely by being recognized convenience and accuracy now generally, is oscillometric blood pressure monitor. However, a change in blood pressure is basically influenced by diverse elements such as each individual`s physiological status and physical condition. Thus, the measurement of blood pressure, which used single element called oscillation in blood pressure of being conveyed to cuff, is not considered on physiological elements such as cardiovascular system status and blood vessel stiffness index, and on external elements, thereby being quite in error. Accordingly, this study detected diverse bio-signals and body informations in each individual as the measurement subject such as ECG, PPG, and Korotkoff Sound in order to enhance convenience and accuracy of measuring blood pressure in the complex measurement equipment, thereby having extracted regression method for compensation in error of oscillometric blood pressure measurement on the wrist, and having improved accuracy of measuring blood pressure. To verify a method of improving accuracy, the blood pressure value in each of SBP, DBP, MAP was acquired through 4-stage experimental procedure targeting totally 51 subjects. Prior to experiment, the subjects were divided into two groups such as the experimental group for extracting regression method and the control group for verifying regression method. Its error was analyzed by comparing the reference blood pressure value, which was obtained through the auscultatory method, and the oscillometric blood pressure value on the wrist. To reduce the detected error, the blood pressure compensation regression method was calculated through multiple linear regression analysis on elements of blood pressure, individual body information, PTT, HR, K-Sound PSD change. Verification was carried out on improving significance and accuracy by applying the regression method to the data of control group. In the experimental results, as a result of confirming error on the reference blood pressure value in SBP, DBP, and MAP, which were acquired through applying regression method, the results of mmHg, mmHg, mmHg could be obtained. This is not only the numerical value of satisfying the sphygmomanometer reference of AAMI, but also shows the lower result than the numerical value in SBP : mmHg, DBP : mmHg, which is the mean error in the experimental results of Brram`s research for verifying accuracy of Omron RX-M, which shows relatively high accuracy among wrist sphygmomanometers. Thus, the blood pressure compensation could be confirmed to be made within significant level.

We demonstrate high responsivity in a polysilicon (Poly-Si) near-infrared photodetector by reducing the adverse effects of grain boundaries. The presence of grain boundaries is a serious problem in polysilicon since they act as traps and degrade the electrical characteristics. However, the relation between grain boundaries and photodetector performance has not yet been reported. Here, the effect of grain boundary on the resistivity and responsivity of Poly-Si devices is investigated. The resistivity of Poly-Si is higher than that of crystalline Si (c-Si) at the same doping concentration due to the potential barrier of the grain boundary, and its degradation of electrical characteristics is mitigated here by increasing the doping concentration. The photodetector with a highly-doped polysilicon layer exhibits a responsivity of 0.48 A/W at 900 nm, which is almost the same as that of c-Si photodetectors. In contrast, polysilicon devices with the same doping concentration as c-Si devices show degraded responsivity due to grain boundary traps. In addition, to improve the responsivity at target wavelengths of 900 nm and 1,064 nm, we deposited an indium-tin-oxide layer, which reduces the surface reflectance on the Poly-Si photodetector. The responsivity is improved by 22.9% and 50.0% at 900 nm and 1,064 nm respectively compared to devices without the ITO. The results here confirm the ability to fabricate low cost Poly-Si photodetectors with high responsivity which show similar or superior optical response compared to commercial c-Si devices.

In this study, we acquired video images from the index finger of subjects using white light emitting diode (WLED) of a smart phone as light source and a camera as optical detector on a frame-by-frame basis, converted the acquired images into red, green and blue (RGB) formats and detected the images in the form of photoplethysmography (PPG) waveforms through real-time video signal processing. Through utilization of secondary derivative photoplethysmography (SDPTG), a PPG second order differential form, the parameters used to monitor arterial stiffness of b/a ratio, d/a ratio and Aging Index (AI) were calculated. From the results of correlation analysis between the value calculated from smart phone and the value calculated by reference equipment, statistically significant results of b/a ratio (r=0.919, p

Hamartoma of the breast is a relatively rare, well-circumscribed benign breast tumour that lacks a true capsule, and is composed primarily of dense, fibrous tissue with associated ducts and a variable amount of fat. A typical mammographic finding is a well-delineated, non-homogeneous mass containing mottled densities corresponding to fat, epithelium and connective tissue. Ultrasonographically, hamartoma has a well-circumscribed heterogeneous internal echo pattern corresponding to areas of fat and soft tissue components. This is the first original paper to describe the MRI findings of hamartomas. Mammography and ultrasonography usually enable a diagnosis of hamartoma; however, gadolinium-DTPA enhanced dynamic MRI is the only method in the preoperative management of atypical hamartomas that allows the exclusion of malignancy elsewhere in the breast and hamartoma.

The pulmonary function test (PFT) is a widely used test in patients or for those who are at risk of respiratory dysfunction. In this study, we aimed to develop a more convenient system, namely, the impedance pulmonary function measurement system (IPFS), for overcoming the restrictions posed by the prevalent spirometric PFT. IPFS employs tetra polar electrodes that can measure pulmonary function using the subjects' hands alone. The impedance measured by IPFS extracts AC values of pulmonary impedance from DC values of body impedance in respiration. This system yields changes in the impedance of volume and flow. In order to verify IPFS, we compared the continuous waveforms obtained from the PFT module and developed IPFS using Pearson linear correlation coefficients (p0.01) for volume and flow. Further, we evaluated the potential application of IPFS for detecting pulmonary functions such as volume (FEV(1)/FVC Ratio) and flow (PEF), and compared the measured parameters between IPFS and spirometric PFT. Our results demonstrate that the measurements obtained using IPFS reflect pulmonary function parameters.

Purpose: To identify sexual function improvement associated with alfuzosin (10 mg daily for 2 years). Materials and Methods: We enrolled 30 men with lower urinary tract symptom (LUTS) who visited Gyeongsang National University Hospital between 2010 and 2012. At first visit, urinalysis, prostate specific antigen, transrectal ultrasound, and uroflowmetry were performed. The nternational Prostate Symptom Score (IPSS), quality of life (QoL), International Index of Erectile Function (IIEF), and Male Sexual Health Questionnaire Ejaculation Function Domain (MSHQ-EjFD) questionnaires were administered, and the subjects answered the same questionnaires at 1 month, 6 months, 1 year, and 2 years of follow-up. Results: Twelve men completed of the entire study. After administration of alfuzosin, the median IPSS at first visit, 1 month, 6 months, 1 year, and 2 years was 18.00 (interquatile range [IQR]: 14.00∼29.75), 20.00 (IQR: 11.50∼30.00), 15.50 (IQR: 8.50∼25.25), 14.50 (IQR: 9.25∼19.50), and 11.50 (IQR: 5.00∼17.75), respectively, which showed an improvement. The median QoL at the same times was 4.50 (IQR: 4.00∼5.00), 4.50 (IQR: 4.00∼5.00), 3.00 (IQR: 2.00∼4.00), 3.50 (IQR: 2.25∼4.00), and 3.00 (IQR: 1.00∼3.00), respectively, and also showed improvement. Likewise, the median IIEF was 36.50 (IQR: 24.50∼46.75), 37.50 (IQR: 26.75∼47.25), 45.50 (IQR: 35.00∼59.75), 48.50 (IQR: 34.75∼62.75), and 47.50 (IQR: 43.25∼61.00), while the median MSHQ-EjFD was 19.00 (IQR: 12.0∼24.75), 19.50 (IQR: 13.50∼27.75), 23.00 (IQR: 19.25∼32.25), 26.50 (IQR: 18.25∼34.50), 27.00 (IQR: 21.50∼32.50), respectively, with both showing improvement. Conclusions: After administration of alfuzosin (10 mg daily for 2 years), the IPSS, QoL, IIEF, and MSHQ-EjFD all improved significantly. This means long-term administration of 10 mg of alfuzosin daily would be effective not only for LUTS but also erectile function and ejaculation.

Purpose: Transrectal ultrasound (TRUS)-guided biopsy of the prostate is usually safe. However, some patients are hospitalized owing to complications from TRUS biopsy. We identified the risk factors for complications and effective preventive measures for treating complications after TRUS biopsy. Materials and Methods: Medical records and radiological images of 1,083 patients who underwent TRUS biopsy of the prostate over 10 years in Gyeongsang National University Hospital were examined retrospectively to investigate the correlation between complications after TRUS biopsy and preventive antibiotics, prebiopsy enema, number of biopsy cores, and pathological findings. Results: Complications occurred in 69 patients (6.4%). The complication rates of the 1,008 patients who received antibiotics and the 75 patients who did not were 6.3% and 8.0%, respectively (p=0.469). Complication rates of the pre-biopsy enema group (n=658) and the group without prebiopsy enema (n=425) were 4.7% and 8.9%, respectively (p=0.007). Complication rates of the 6-core biopsy group (n=41) and the 12-core biopsy group (n=955) were 7.3% and 6.3%, respectively (p=0.891). Complication rates of the prostate cancer group (n=306) and the no prostate cancer group (n=713) were 6.2% and 6.6%, respectively (p=0.740). Conclusions: A prebiopsy enema was associated with a reduced risk of complications after TRUS biopsy. Preventive antibiotics, number of biopsy cores, and pathological findings did not significantly influence the complication rate.