Virus-templated redox nanowire network for enzyme electrode.

Viruses have unique coat proteins that are genetically modifiable. Their surface can serve as a nano-template on which electroactive molecules are immobilized. In this study, we report filamentous bacteriophage as a backbone to which redox mediators are covalently and densely tethered, constructing redox nanowire, i.e. an electron conducting biomaterial. The highly ordered coat proteins of a filamentous bacteriophage provide flexible and biocompatible platform to constitute a biohybrid redox nanowire. Incorporating bacteriophage and redox molecules form an entangled assembly of nanowires enabling facile electron transfer. Electron transfer among the molecular mediators in the entangled assembly originates apparent electron diffusion of which the electron transfer rate is comparable to that observed in conventional redox polymers. Programming peptide terminals suggests further enhancement in electron mediation by increasing redox species mobility. In addition, the redox nanowire film functions as a favorable matrix for enzyme encapsulation. The stability of the enzymes entrapped in this unique matrix is substantially improved.

Three-dimensional imaging and analysis of pathological tissue samples with de novo generation of citrate-based fluorophores.

Two-dimensional (2D) histopathology based on the observation of thin tissue slides is the current paradigm in diagnosis and prognosis. However, labeling strategies in conventional histopathology are limited in compatibility with 3D imaging combined with tissue clearing techniques. Here, we present a rapid and efficient volumetric imaging technique of pathological tissues called 3D tissue imaging through de novo formation of fluorophores, or 3DNFC, which is the integration of citrate-based fluorogenic reaction DNFC and tissue clearing techniques. 3DNFC markedly increases the fluorescence intensity of tissues by generating fluorophores on nonfluorescent amino-terminal cysteine and visualizes the 3D structure of the tissues to provide their anatomical morphology and volumetric information. Furthermore, the application of 3DNFC to pathological tissue achieves the 3D reconstruction for the unbiased analysis of diverse features of the disorders in their natural context. We suggest that 3DNFC is a promising volumetric imaging method for the prognosis and diagnosis of pathological tissues.

De novo formation of citrate-based fluorophores on N-termini of peptides and proteins in cells and tissues.

We developed a new method for the de novo formation of fluorophores based on citrate (DNFC) in biological samples. Use of an amide coupling reagent and microwave irradiation greatly facilitates the fluorophore formation on peptides and proteins with N-terminal cysteine or serine. Since N-terminal cysteine and serine can form thiazolopyridone- or oxazolopyridone-based fluorophores emitting blue and green fluorescence, respectively, by the DNFC staining, each organelle, cell and tissue exhibited a characteristic fluorescence distribution. The DNFC staining is able to provide a new potential protocol for future cell imaging, histology and diagnosis.

Calcium-Binding Polymer-Coated Poly(lactide- co-glycolide) Microparticles for Sustained Release of Quorum Sensing Inhibitors to Prevent Biofilm Formation on Hydroxyapatite Surfaces.

Quorum sensing (QS) inhibitor-based therapy is an attractive strategy to inhibit bacterial biofilm formation without excessive induction of antibiotic resistance. Thus, we designed Ca2+-binding poly(lactide- co-glycolide) (PLGA) microparticles that can maintain a sufficient concentration of QS inhibitors around hydroxyapatite (HA) surfaces in order to prevent biofilm formation on HA-based dental or bone tissues or implants and, therefore, subsequent pathogenesis. Poly(butyl methacrylate- co-methacryloyloxyethyl phosphate) (PBMP) contains both Ca2+-binding phosphomonoester groups and PLGA-interacting butyl groups. The PBMP-coated PLGA (PLGA/PBMP) microparticles exhibited superior adhesion to HA surfaces without altering the sustained release properties of uncoated PLGA microparticles. PLGA/PBMP microparticle-encapsulating furanone C-30, a representative QS inhibitor, effectively inhibited the growth of Streptococcus mutans and its ability to form biofilms on HA surface for prolonged periods of up to 100 h, which was much longer than either furanone C-30 in its free form or when encapsulated in noncoated PLGA microparticles.

Chemoselective Tyrosine Bioconjugation through Sulfate Click Reaction.

A novel and selective tyrosine functionalization strategy through SuFEx (sulfur fluoride exchange) chemistry is presented. In this approach, free tyrosine (Tyr) reacts selectively with aryl fluorosulfate in the presence of various nucleophilic amino acid residues in bio-tolerable conditions. Chemoselectivity of this unique SuFEx reaction was confirmed in amino acid, peptide, and protein conjugations. The functions of peptides and proteins were well-preserved as demonstrated from the Tyr-specific modification of cell-penetrating peptide and erythropoietin. This method is well-suited for residue-specific modification of native proteins, and thus would expand the versatility of bio-conjugation in protein chemistry.

A Rotator Cuff Tear Concomitant With Shoulder Stiffness Is Associated With a Lower Retear Rate After 1-Stage Arthroscopic Surgery.

BACKGROUND: Few studies have reported on the radiological characteristics and repair integrity of coexistent rotator cuff tears (RCTs) and shoulder stiffness after simultaneous arthroscopic rotator cuff repair and capsular release. PURPOSE: To evaluate the radiological characteristics and repair integrity of 1-stage arthroscopic surgery of RCTs concomitant with shoulder stiffness. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Among patients who underwent arthroscopic repair of full-thickness RCTs, the stiff group underwent simultaneous capsular release for shoulder stiffness, and the nonstiff group had no stiffness. Symptom duration, prevalence of diabetes, tear size, tendon involvement (type 1, supraspinatus; type 2, supraspinatus and subscapularis; and type 3, supraspinatus and infraspinatus; type 4, supraspinatus, subscapularis, and infraspinatus), and fatty infiltration (Goutallier stages 0-4) were evaluated. A retear was appraised using magnetic resonance imaging, and clinical outcomes were assessed using range of motion, the Korean Shoulder Scoring System (KSS), and the University of California, Los Angeles (UCLA) shoulder score. RESULTS: The stiff group showed a significantly lower retear rate (1/39, 2.6%) than the nonstiff group (47/320, 14.7%) ( P = .043). There were significant differences in symptom duration (7.4 ± 6.6 vs 15.0 ± 23.7 months, respectively; P < .001), mediolateral tear size (18.9 ± 8.9 vs 24.1 ± 12.0 mm, respectively; P = .002), tendon involvement (94.9%, 5.1%, 0.0%, and 0.0% vs 85.3%, 6.9%, 7.8%, and 0.0%, respectively; P = .048), and fatty infiltration of the subscapularis (66.7%, 33.3%, 0.0%, 0.0%, and 0.0% vs 31.9%, 61.3%, 5.6%, 1.3%, and 0.0%, respectively; P < .001) and teres minor (74.4%, 20.5%, 5.1%, 0.0%, and 0.0% vs 47.2%, 48.8%, 3.8%, 0.0%, and 0.3%, respectively; P = .007) between the stiff and nonstiff groups. Preoperatively, the stiff group showed significantly worse forward flexion (95.9° ± 23.6° vs 147.7° ± 4.2°, respectively; P < .001), external rotation (17.4° ± 10.1° vs 51.6° ± 12.1°, respectively; P < .001), and internal rotation (L5 vs L2, respectively; P < .001) and lower KSS (52.1 ± 13.8 vs 66.3 ± 13.5, respectively; P < .001) and UCLA scores (18.7 ± 4.8 vs 22.5 ± 4.5, respectively; P < .001) than the nonstiff group. However, these differences became insignificant from 3 months postoperatively for forward flexion ( P > .05) and KSS ( P > .05) and UCLA scores ( P > .05), from 1 year postoperatively for external rotation ( P > .05), and at the last follow-up for internal rotation ( P > .05). A multiple logistic regression analysis revealed that only mediolateral tear size (odds ratio, 1.043; P = .014) and type 2 tendon involvement (odds ratio, 4.493; P = .003) were independent predictors of a retear. CONCLUSION: RCTs concomitant with shoulder stiffness showed a smaller mediolateral tear size, anterosuperior tendon involvement, and less severe fatty infiltration preoperatively and better repair integrity postoperatively than RCTs without stiffness. Furthermore, the clinical outcomes and range of motion at final follow-up were similar between the 2 groups.

Anti-inflammatory and Antibacterial Effects of Covalently Attached Biomembrane-Mimic Polymer Grafts on Gore-Tex Implants.

Expanded polytetrafluoroethylene (ePTFE), also known as Gore-Tex, is widely used as an implantable biomaterial in biomedical applications because of its favorable mechanical properties and biochemical inertness. However, infection and inflammation are two major complications with ePTFE implantations, because pathogenic bacteria can inhabit the microsized pores, without clearance by host immune cells, and the limited biocompatibility can induce foreign body reactions. To minimize these complications, we covalently grafted a biomembrane-mimic polymer, poly(2-methacryloyloxylethyl phosphorylcholine) (PMPC), by partial defluorination followed by UV-induced polymerization with cross-linkers on the ePTFE surface. PMPC grafting greatly reduced serum protein adsorption as well as fibroblast adhesion on the ePTFE surface. Moreover, the PMPC-grafted ePTFE surface exhibited a dramatic inhibition of the adhesion and growth of Staphylococcus aureus, a typical pathogenic bacterium in ePTFE implants, in the porous network. On the basis of an analysis of immune cells and inflammation-related factors, i.e., transforming growth factor-ß (TGF-ß) and myeloperoxidase (MPO), we confirmed that inflammation was efficiently alleviated in tissues around PMPC-grafted ePTFE plates implanted in the backs of rats. Covalent PMPC may be an effective strategy for promoting anti-inflammatory and antibacterial functions in ePTFE implants and to reduce side effects in biomedical applications of ePTFE.

Amine-selective affinity resins based on pH-sensitive reversible formation of covalent bonds.

A new class of affinity resins using reversible covalent bonds is introduced for the separation of amine-containing molecules. pH-sensitive reversible formation of amic acid bonds between amines and carboxylate dimethyl maleic anhydride-decorated wrinkled silica nanoparticle resins was used to selectively retain and release amine-containing molecules, by controlling the pH.

Association between serum ferritin and hemoglobin levels and bone health in Korean adolescents: A nationwide population-based study.

It is important to identify risk factors for low bone mass at a young age. An influence of iron store on bone health in the general population has been reported but has not been studied in adolescents. This study aimed to investigate the relationship between hemoglobin and serum ferritin levels and bone mineral content (BMC) in South Korean adolescents.This study was based on data collected during the 2009to 2010 Korea National Health and Nutrition Examination Survey. We included 1321 participants aged 10 to 18 years. BMC was measured at the femur and lumbar spine using dual-energy x-ray absorptiometry, and hemoglobin and serum ferritin levels were examined.In boys, hemoglobin and serum ferritin levels were positively associated with BMC of the total femur and lumbar spine after adjusting for confounders, and hemoglobin levels significantly increased as BMC increased at all sites (P for trend = .001 for total femur, .01 for femur neck, and <.001 for lumbar spine). Likewise, serum ferritin levels showed increasing trends according to increasing BMC of the total femur and lumbar spine in boys (P for trend = .04 for total femur; and <.001 for lumbar spine). However, these associations were not observed in girls.This study suggests a positive relationship between serum ferritin and hemoglobin levels and BMC in South Korean adolescent boys.

Empirical Study on Designing of Gaze Tracking Camera Based on the Information of User's Head Movement.

Gaze tracking is the technology that identifies a region in space that a user is looking at. Most previous non-wearable gaze tracking systems use a near-infrared (NIR) light camera with an NIR illuminator. Based on the kind of camera lens used, the viewing angle and depth-of-field (DOF) of a gaze tracking camera can be different, which affects the performance of the gaze tracking system. Nevertheless, to our best knowledge, most previous researches implemented gaze tracking cameras without ground truth information for determining the optimal viewing angle and DOF of the camera lens. Eye-tracker manufacturers might also use ground truth information, but they do not provide this in public. Therefore, researchers and developers of gaze tracking systems cannot refer to such information for implementing gaze tracking system. We address this problem providing an empirical study in which we design an optimal gaze tracking camera based on experimental measurements of the amount and velocity of user's head movements. Based on our results and analyses, researchers and developers might be able to more easily implement an optimal gaze tracking system. Experimental results show that our gaze tracking system shows high performance in terms of accuracy, user convenience and interest.

Wrinkled silica/titania nanoparticles with tunable interwrinkle distances for efficient utilization of photons in dye-sensitized solar cells.

Efficient light harvesting is essential for the realization of high energy conversion efficiency in dye-sensitized solar cells (DSCs). State-of-the-art mesoporous TiO2 photoanodes fall short for collection of long-wavelength visible light photons, and thus there have been efforts on introduction of scattering nanoparticles. Herein, we report the synthesis of wrinkled silica/titania nanoparticles with tunable interwrinkle distances as scattering materials for enhanced light harvesting in DSCs. These particles with more than 20 times larger specific surface area (>400 m(2)/g) compared to the spherical scattering particles (<20 m(2)/g) of the similar sizes gave rise to the dye-loading amounts, causing significant improvements in photocurrent density and efficiency. Moreover, dependence of spectral scattering properties of wrinkled particles on interwrinkle distances, which was originated from difference in overall refractive indices, was observed.

Compensation Method of Natural Head Movement for Gaze Tracking System Using an Ultrasonic Sensor for Distance Measurement.

Most gaze tracking systems are based on the pupil center corneal reflection (PCCR) method using near infrared (NIR) illuminators. One advantage of the PCCR method is the high accuracy it achieves in gaze tracking because it compensates for the pupil center position based on the relative position of corneal specular reflection (SR). However, the PCCR method only works for user head movements within a limited range, and its performance is degraded by the natural movement of the user's head. To overcome this problem, we propose a gaze tracking method using an ultrasonic sensor that is robust to the natural head movement of users. Experimental results demonstrate that with our compensation method the gaze tracking system is more robust to natural head movements compared to other systems without our method and commercial systems.

Estimation of Gaze Detection Accuracy Using the Calibration Information-Based Fuzzy System.

Gaze tracking is a camera-vision based technology for identifying the location where a user is looking. In general, a calibration process is applied at the initial stage of most gaze tracking systems. This process is necessary to calibrate for the differences in the eyeballs and cornea size of the user, as well as the angle kappa, and to find the relationship between the user's eye and screen coordinates. It is applied on the basis of the information of the user's pupil and corneal specular reflection obtained while the user is looking at several predetermined positions on a screen. In previous studies, user calibration was performed using various types of markers and marker display methods. However, studies on estimating the accuracy of gaze detection through the results obtained during the calibration process have yet to be carried out. Therefore, we propose the method for estimating the accuracy of a final gaze tracking system with a near-infrared (NIR) camera by using a fuzzy system based on the user calibration information. Here, the accuracy of the final gaze tracking system ensures the gaze detection accuracy during the testing stage of the gaze tracking system. Experiments were performed using a total of four types of markers and three types of marker display methods. From them, it was found that the proposed method correctly estimated the accuracy of the gaze tracking regardless of the various marker and marker display types applied.

A new gaze estimation method considering external light.

Gaze tracking systems usually utilize near-infrared (NIR) lights and NIR cameras, and the performance of such systems is mainly affected by external light sources that include NIR components. This is ascribed to the production of additional (imposter) corneal specular reflection (SR) caused by the external light, which makes it difficult to discriminate between the correct SR as caused by the NIR illuminator of the gaze tracking system and the imposter SR. To overcome this problem, a new method is proposed for determining the correct SR in the presence of external light based on the relationship between the corneal SR and the pupil movable area with the relative position of the pupil and the corneal SR. The experimental results showed that the proposed method makes the gaze tracking system robust to the existence of external light.

Prevalence and control of hypertension and albuminuria in South Korea: focus on obesity and abdominal obesity in the Korean National Health and Nutrition Examination Survey, 2011-2012.

BACKGROUND: Albuminuria is associated with cardiovascular disease, and the relationship between albuminuria and hypertension is well established in many studies. So the control of hypertension is critical for decreasing cardiovascular events and albuminuria. Obesity and abdominal obesity are also associated with hypertension and albuminuria. Therefore, we analyzed the relationship between albuminuria and the prevalence and control of hypertension in the general Korean population according to obesity status. METHODS: We analyzed data from the 2011-2012 Korea National Health and Nutrition Examination Survey, and 9,519 subjects were included. Subjects were divided into four groups: non-obese/normal waist circumference, non-obese/high waist circumference, obese/normal waist circumference, and obese/high waist circumference. RESULTS: Systolic blood pressure and diastolic blood pressure were positively associated with albumin-creatinine ratio in all groups (all p values <0.005). Non-obese/normal waist circumference group were more likely to have hypertension (odds ratios [95% confidential intervals (CIs)] were 3.20 [2.21-4.63] in microalbuminuria level and 3.09 [1.05-9.14] in macroalbuminuria level), and less likely to have controlled hypertension (odds ratios <1 for both albuminuria levels) after adjusting for all covariates. Obese/normal waist circumference group were also more likely to have hypertension (odds ratio [95% CI] were 3.10 [1.56-6.15] in microalbuminuria level and 21.75 [3.66-129.04] in macroalbuminuria level), and less likely to have controlled hypertension in macroalbuminuria level (odds ratio [95% CI], 0.04 [0.01-0.15]). CONCLUSIONS: Non-obese and normal waist circumference subjects have an increased prevalence and decreased control of hypertension in microalbuminuria and macroalbuminuria levels. Screening for albuminuria may provide helpful information about hypertension and blood pressure control, particularly in the non-obese and normal waist circumference subjects.

Nonwearable gaze tracking system for controlling home appliance.

A novel gaze tracking system for controlling home appliances in 3D space is proposed in this study. Our research is novel in the following four ways. First, we propose a nonwearable gaze tracking system containing frontal viewing and eye tracking cameras. Second, our system includes three modes: navigation (for moving the wheelchair depending on the direction of gaze movement), selection (for selecting a specific appliance by gaze estimation), and manipulation (for controlling the selected appliance by gazing at the control panel). The modes can be changed by closing eyes during a specific time period or gazing. Third, in the navigation mode, the signal for moving the wheelchair can be triggered according to the direction of gaze movement. Fourth, after a specific home appliance is selected by gazing at it for more than predetermined time period, a control panel with 3 × 2 menu is displayed on laptop computer below the gaze tracking system for manipulation. The user gazes at one of the menu options for a specific time period, which can be manually adjusted according to the user, and the signal for controlling the home appliance can be triggered. The proposed method is shown to have high detection accuracy through a series of experiments.

The Impact of Body Weight Change on Bone Mineral Density of the Lumbar Spine in Perimenopausal Women: A Retrospective, One-year Follow-up Study.

BACKGROUND: Low body weight was one of the risk factors of osteoporosis. Little is known about the correlation between body weight change and bone mineral density (BMD) in Korean women. Therefore, this study was designed to reveal the impact of body weight change on BMD of the lumbar spine in perimenopausal women. METHODS: 105 healthy perimenopausal women aged between 44 and 50 years old were enrolled from August 2002 to March 2009. BMD was measured by dual energy X-ray absorptiometry. Partial correlation coefficients between body weight change and BMD change were calculated after the adjustments for several variables. BMD changes among groups based on BMI and the percentage change in body weight during 1-year follow-up period were compared. RESULTS: At both baseline and year 1, BMD of lumbar spine tended to be associated more with body weight. There was a significant association between body weight change and BMD change in lumbar spine during 1-year follow-up period. The weight gain group relatively showed an increase in BMD of lumbar spines than weight loss group. There was no BMD change in BMI less than 23 kg/m(2) group, but in case of BMI more than 23 kg/m(2) group, BMD in weight gain group increased more than the weight maintaining group. CONCLUSION: This study demonstrated that body weight change is associated with change in BMD of lumbar spine in perimenopausal women especially if they are overweight.