Simultaneous enhancement in phosphorescence and its lifetime of PtOEP-peptide assembly triggered by protein interaction.

We fabricated hybrid nanoparticles consisting of organic semiconducting material with peptide sequence to reflect the target protein interaction. A phosphorescent OLED material, platinum octaethylporphyrin (PtOEP) was self-assembled by reprecipitation with the A17 peptide (YCAYYSPRHKTTF) selected as a probe ligand in order to recognize heat shock protein 70 (HSP70). The phosphorescence intensity of the PtOEP-A17 assembly was enhanced by 125 % after treatment with HSP70. The specificity of the protein interaction was confirmed in both solution and solid states of the PtOEP-A17 assembly against to BSA and nucleolin. We figured out that the phosphorescence lifetime of PtOEP-A17 assembly after exposed to HSP70 increased significantly to 153 ns from initial 115 ns. These simultaneous enhancements in phosphorescence and lifetime triggered by the specific protein interaction would open new applications of PtOEP, a representative material of light-emitting device fields.

Energy Transfer-Based Recognition of Membrane Cholesterol by Controlling Intradistance of Linker.

Gold nanoparticles (AuNPs) are good candidates for donor material in energy transfer systems and can easily be functionalized with various ligands on the surface with Au-S bonding. Cyclodextrin (CD) forms inclusion complexes with fluorophores due to its unique structure for host-guest interaction. In this study, we fabricated ßCD-functionalized AuNPs using different lengths of thiol ligands and recognized cholesterol to confirm the energy-transfer-based turn-on fluorescence mechanism. AuNP-ßCD conjugated with various thiol ligands and quenched the fluorescein (Fl) dye, forming ßCD-Fl inclusion complexes. As the distance between AuNPs and ßCD decreased, the quenching efficiency became higher. The quenched fluorescence was recovered when the cholesterol replaced the Fl because of the stronger binding affinity of the cholesterol with ßCD. The efficiency of cholesterol recognition was also affected by the energy transfer effect because the shorter ßCD ligand had a higher fluorescence recovery. Furthermore, we fabricated a liposome with cholesterol embedded in the lipid bilayer membrane to mimic the cholesterol coexisting with lipids in human serum. These cellular cholesterols accelerated the replacement of the Fl molecules, resulting in a fluorescence recovery higher than that of pure lipid. These discoveries are expected to give guidance towards cholesterol sensors or energy-transfer-based biosensors using AuNPs.

Fabrication and Characterization of Three-Dimensional Microelectromechanical System Coaxial Socket Device for Semiconductor Package Testing.

With the continuous reduction in size and increase in density of semiconductor devices, there is a growing demand for contact solutions that enable high-speed testing in automotive, 5G, and artificial intelligence-based devices. Although existing solutions, such as spring pins and rubber sockets, have been effective in various applications, there is still a need for new solutions that accommodate fine-pitch, high-speed, and high-density requirements. This study proposes a novel three-dimensional microelectromechanical system spring structure coaxial socket for semiconductor chip package testing. The socket design incorporates impedance matching for high-speed testing and addresses the challenges of fine-pitch and high-density applications. Mechanical tests are conducted to evaluate the durability of the structure and electrical tests are performed to verify electrical characteristics by utilizing a vector network analyzer up to 60 GHz. Our results have revealed promising performance and will help in further optimizing the design for potential production in the field and industry.

Triple-Peak Photoluminescence of DNA-Hybrid Alq3 Crystals Emitting a Depressed Single Peak upon Bio-Recognition.

The green organic semiconductor, tris-(8-hydroxyquinoline)aluminum (Alq3), was hybridized with DNA growing in the shape of hexagonal prismatic crystals. In this study, we applied hydrodynamic flow to the fabrication of Alq3 crystals doped with DNA molecules. The hydrodynamic flow in the Taylor-Couette reactor induced nanoscale pores in the Alq3 crystals, especially at the side part of the particles. The particles exhibited distinctly different photoluminescence emissions divided into three parts compared to common Alq3-DNA hybrid crystals. We named this particle a "three-photonic-unit". After treatment with complementary target DNA, the three-photonic-unit Alq3 particles doped with DNAs were found to emit depressed luminescence from side parts of the particles. This novel phenomenon would expand the technological value of these hybrid crystals with divided photoluminescence emissions toward a wider range of bio-photonic applications.

Sustainable colorimetric/luminescent sensors enabled by armored lipid nanoparticles.

In this study, we developed a highly stable polymeric vesicle using a nanosilica-armor membrane to achieve a sustainable colorimetric/luminescent response. The silica armor can be grown directly as ~ 5 nm spherical nanoparticles on the surface of the diacetylene (DA) vesicle with liposomal structure. This can be accomplished via the modified Stöber reaction in pure water on a layer of amine linkers deposited on the vesicles. Once formed, the structural stability of the DA vesicles dramatically increased and remained so even in a dried powder form that could be stored for a period of approximately 6 months. Then, redispersed in water, the armored vesicles did not agglomerate because of the electric charge of the silica armor. After polymerization, the polydiacetylene (PDA) vesicles maintained an average of 87.4% their sensing capabilities compared to unstored vesicles. Furthermore, the silica membrane thickness can be controlled by reiteration of the electrostatic layer-by-layer approach and the direct hydrolysis of silica. As the number of silica armor membranes increases, the passage of the stimuli passing through the membranes becomes longer. Consequently, three layers of silica armor gave the PDA vesicles size-selective recognition to filter out external stimuli. These discoveries are expected to have large-scale effects in the chemo- and biosensor fields by applying protective layers to organic nanomaterials.

Anti-fracture Efficacy of Monthly Risedronate Compared with That of Weekly Risedronate in Postmenopausal Korean Women with Osteoporosis: A Nationwide Cohort Study.

BACKGROUND: Intermittent dosing regimens for oral risedronate (once-monthly and once-weekly) were developed for patient convenience. While several studies have reported the anti-fracture efficacy of weekly dosing, few have assessed monthly dosing. The lower efficacy of monthly dosing has been previously suggested. The aim of this study was to compare the anti-fracture efficacy of monthly and weekly dosing. METHODS: We obtained information from the Korea National Health Insurance Service database from 2012 to 2017 of Korean women of ≥50 years of age who used weekly or monthly risedronate. We compared the time of occurrence of the first osteoporotic fracture after the first prescription of risedronate. Using a Cox proportional model, we assessed incidence rate ratios (IRRs) with 95% confidence intervals (CIs) for fractures at any site, and the hip, vertebral, and non-vertebral sites between both regimens. Propensity score weighting was used to balance the treatment groups. RESULTS: The study populations were distributed according to dosing frequency (monthly, 27,329; weekly, 47,652). There was no significant difference in the incidence rate of new fractures in any site (IRR, 1.008; 95% CI,0.963- 1.055; P=0.737), hip (IRR, 0.999; 95% CI, 0.769-1.298; P=0.996), vertebral (IRR, 0.962; 95% CI, 0.890-1.040; P=0.330), or non-vertebral (1.022; 95% CI, 0.968-1.078; P=0.439) sites between monthly and weekly risedronate. CONCLUSION: The anti-fracture efficacy at any site and the examined individual sites was similar for the monthly and weekly risedronate regimens. Large-scale randomized controlled trials are required for confirmation.

Analysis of the reliability of the make test in young adults by using a hand-held dynamometer.

[Purpose] The purpose of this study was to analyze intra-rater and inter-rater reliabilities of the make test, a manual muscle testing measurement method, using a hand-held dynamometer in Korean young adults. [Subjects and Methods] A total of 42 university students participated in this study. The make test, a manual muscle testing method, was conducted. A hand-held dynamometer was used to measure elbow joint flexion during the make test. [Results] Both intra-rater (the intraclass correlation coefficient=0.992) and inter-rater reliabilities (the intraclass correlation coefficient=0.949) were excellent, with values over 0.9. [Conclusion] The make test is a useful manual muscle testing method with high intra-rater and inter-rater reliability.

The effects of t'ai chi on muscle activity, pain, and balance in females in their 20s with acute low back pain.

[Purpose] This study was conducted in order to examine the effects of t'ai chi on females in their 20s with acute low back pain. The subjects were 30 females in their 20s with acute low back pain. [Subjects and Methods] They were equally and randomly divided into a t'ai chi group and a stretching group. The intervention was applied three times per week, one hour each time, for a total of eight weeks. During the one hour, the subjects conducted warm-up exercises for 10 min, primary exercises for 40 min, and cool-down exercises for 10 min. In order to examine changes in low back pain in the patients according to the intervention method, muscle activity, pain, and balance elements (left and right side movement distance, forward and backward movement distance) were measured. [Results] Muscle activity and the visual analog scale score significantly decreased in both the t'ai chi group and the stretching group. Regarding changes in balance elements, the t'ai chi group's left and right side movement distance decreased, which was statistically significant. However, the t'ai chi group's forward and backward movement distance and the stretching group's forward and backward movement distance and left and right side movement distance did not change. [Conclusion] According to the results of this study, t'ai chi is considered an appropriate exercise program to reduce acute low back pain in females in their 20s. This is because when compared with stretching, it enables posture maintenance with lesser force due to decreased muscle activity, it is more helpful for improvements in balance ability, and it is effective in decreasing pain.

Comparison of the Effects on Dynamic Balance Ability of Warming up in Water Versus on the Ground.

[Purpose] This research was designed to find out how the so-called "dynamic balance" is affected by doing different types of warm up exercises. In particular, the research is focused on the difference in the effect on dynamic Balance of warming up in water versus on the ground. [Subjects and Methods] Twenty healthy adults were the subjects of this study, with 10 people assigned each to two groups, one warming up in water and another warming up on the ground. The dynamic balance was measured for all subjects before the warming up. The group warming up on the ground conducted active stretching on the ground, and the group warming up in water conducted stretching in water by using water as resistance. [Results] The results indicate that warming up in water has a more powerful effect on a subject's dynamic balance than warming up on the ground. [Conclusion] The group warming up in water, who made use of the viscosity and flow of the water, showed better balance than the group warming up on the ground. Warming up in water, which entails an element of resistance, should be implemented in warm-up routines in the future.

Surface EMG during the Push-up plus Exercise on a Stable Support or Swiss Ball: Scapular Stabilizer Muscle Exercise.

[Purpose] Scapular stabilizer strengthening exercise is crucial for shoulder rehabilitation. The purpose of this study was to compare two types of push-up plus exercises, on a stable and unstable bases of support, using surface electromyography (EMG), to suggest an effective shoulder rehabilitation program. [Subjects and Methods] Ten healthy men volunteered for this study. All volunteers performed two sets of push-up plus exercise (standard push up and knee push up) on stable and unstable bases of support. The muscle activities of five important scapular stabilizer muscles (upper trapezius, middle trapezius, lower trapezius, serratus anterior, latissimus dorsi) were recorded during the exercise. [Results] The upper trapezius showed greater mean electric activation amplitude in the scapular retraction posture than in the scapular protraction posture, and the serratus anterior showed greater mean electric activation amplitude in the scapular protraction posture than in the scapular retraction posture. The root-mean-square normalized EMG values of the muscles were greater during the exercise performed on the unstable support than those on the stable support. [Conclusion] The standard push-up plus exercise on an unstable base of support helps to increase muscle activity, especially those of the upper/middle trapezius and serratus anterior.

Changes in the activities of the trunk muscles in different kinds of bridging exercises.

[Purpose] The purpose of this study was to examine the effects of different types of bridging exercises on the activities of the trunk muscles. [Methods] Twenty-four students participated in this experiment. The activities of the internal oblique (IO), external oblique (EO), rectus abdominis (RA), and erector spinae (ES) muscles were measured in four different bridging exercises. [Results] There were significant differences in the IO, EO, RA, and ES among the four kinds of bridging exercise. The activities of IO, EO and RA were the highest in prone bridging (exercise 4), followed by unilateral bridging (exercise 3), and supine bridging on balance pads (exercise 2). In conventional bridging (exercise 1), the activities of IO, EO, and RA were the lowest. The activity of ES was the highest in exercise 3 followed by exercises 2 and 1. The activity of ES was the lowest than in exercise 1. [Conclusions] Bridging exercise in the prone position may be a more effective method of enhancing trunk muscle activities exercises in other positions.

Melatonin stimulates glucose transport via insulin receptor substrate-1/phosphatidylinositol 3-kinase pathway in C2C12 murine skeletal muscle cells.

The prevalence of diabetes has exponentially increased in recent decades due to environmental factors such as nocturnal lifestyle and aging, both of which influence the amount of melatonin produced in the pineal gland. The present study investigated the effect of melatonin on signaling pathways of glucose transport in C2C12 mouse skeletal muscle cells. Intriguingly, treatment of C2C12 cells with melatonin (1 nm) stimulated glucose uptake twofold increase. Melatonin-stimulated glucose transport was inhibited with co-treatment with the melatonin receptor antagonist luzindole. Furthermore, treatment of stably over-expressed melatonin receptor type 2B containing C2C12 myotubes with melatonin amplified glucose transport c. 13-fold. Melatonin also increased the phosphorylation level of insulin receptor substrate-1 (IRS-1) and the activity of phosphoinositide 3-kinase (PI-3-kinase). However, 3',5'-cyclic adenosine monophosphate-activated protein kinase (AMPK), another important glucose transport stimulatory mediator via an insulin-independent pathway, was not influenced by melatonin treatment. Activity of p38 mitogen-activated protein kinase (MAPK), a downstream mediator of AMPK, was also not changed by melatonin. In addition, melatonin increased the expression level of forkhead box A2, which was recently discovered to regulate fatty acid oxidation and to be inhibited by insulin. In summary, melatonin stimulates glucose transport to skeletal muscle cells via IRS-1/PI-3-kinase pathway, which implies, at the molecular level, its role in glucose homeostasis and possibly in diabetes. Additionally, exposure to light at night and aging, both of which lower endogenous melatonin levels may contribute to the incidence and/or development of diabetes.

5-Aminoimidazole-4-carboxamide riboside suppresses lipopolysaccharide-induced TNF-alpha production through inhibition of phosphatidylinositol 3-kinase/Akt activation in RAW 264.7 murine macrophages.

5-Aminoimidazole-4-carboxamide riboside (AICAR) is an adenosine analog and a widely used activator of AMP-activated protein kinase (AMPK). We examined the effect of AICAR on LPS-induced TNF-alpha production in RAW 264.7 and peritoneal macrophages and its molecular mechanism in RAW 264.7 macrophages. Treatment with AICAR inhibited LPS-induced increases in TNF-alpha mRNA and protein levels in these cells. AICAR or LPS did not alter the AMPK activity as well as the phosphorylations of AMPK alpha (Thr172) and ACC (Ser79). Moreover, an adenosine kinase inhibitor 5'-iodotubercidin enhanced the suppressive effect of AICAR on TNF-alpha levels. These results suggest that the effect of AICAR on TNF-alpha suppression in RAW 264.7 cells is independent of AMPK activation. In addition, an adenosine receptor antagonist 8-SPT had no effect on AICAR-induced suppression of TNF-alpha levels. Finally, we observed that AICAR inhibited LPS-induced activation of PI 3-kinase and Akt, whereas it had no effect on the activation of p38 and ERK1/2. Taken together, these results suggest that the anti-inflammatory action of AICAR in RAW 264.7 macrophages is independent of AMPK activation and is associated with inhibition of LPS-induced activation of PI 3-kinase/Akt pathway.

Differential regulation of phosphatidylinositol 3-kinase/Akt, mitogen-activated protein kinase, and AMP-activated protein kinase pathways during menadione-induced oxidative stress in the kidney of young and old rats.

We investigated regulation of various signal transduction pathways during oxidative stresses in the kidney of young and aged rats. Menadione-induced regulation of molecules in PI 3-kinase, MAPK, and AMPK pathways was determined in the young (2 months) and old (24 months) groups. PI 3-kinase activity and Akt phosphorylation were significantly reduced in the old compared with the young. PTEN tumor suppressor was also lower in its expression and phosphorylation levels in the old. Response of the molecules in PI 3-kinase pathway to menadione was minimized. In contrast, over 5-fold induction of ERK1/2 phosphorylation by menadione was observed in both groups. On the other hand, basal activities as well as menadione-induced activities of JNK1 and AMPK were higher in the old than in the young. While p27(Kip1), p53, and p21(Waf1) were slightly increased by menadione in both groups, the basal induction level in the old was considerably higher. In conclusion, the results suggest that the age-related down-regulation of PI 3-kinase/Akt pathway and up-regulation of JNK1, AMPK, and p53 pathways may be responsible for the increased susceptibility to oxidative stress.

5-Aminoimidazole-4-carboxamide-ribonucleoside enhances oxidative stress-induced apoptosis through activation of nuclear factor-kappaB in mouse Neuro 2a neuroblastoma cells.

AMP-activated protein kinase (AMPK) was recently suggested to have a pro-apoptotic effect although its primary function is believed to mediate cellular adaptation to metabolic stresses. Here, we investigated the effect of the AMPK activator 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) on oxidative stress-induced apoptosis using mouse Neuro 2a neuroblastoma cells. H2O2-induced apoptosis was increased by AMPK activation, either with AICAR pretreatment or with overexpression of active AMPK. AICAR also induced nuclear factor-kappaB (NF-kappaB) activation along with activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase. Correlation between NF-kappaB activation and the AICAR-enhanced apoptotic cell death was observed. In addition, NF-kappaB inhibitor SN50 prevented the augmented cell death by AICAR. Thus, our data suggest that NF-kappaB mediates the pro-apoptotic effect of AICAR.

Caffeine induces apoptosis in human neuroblastoma cell line SK-N-MC.

Caffeine is one of the most widely consumed neuroactive drugs, coming mostly from everyday beverages such as coffee and tea. To investigate whether caffeine induces apoptosis in the central nervous system, 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay, 4,6-diamidino-2-phenylindole (DAPI) staining, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay, flow cytometric analysis, DNA fragmentation assay, and caspase-3 enzyme assay were performed on SK-N-MC human neuroblastoma cells. Cells treated with caffeine at concentrations as high as 10 mM exhibited several characteristics of apoptosis. In addition, caffeine was shown to increase the caspase-3 activity. These results suggest that high-dose of caffeine induces apoptosis in human neuroblastoma cells, probably by increasing the caspase-3 enzyme activity.

Tetrandrine cytotoxicity and its dual effect on oxidative stress-induced apoptosis through modulating cellular redox states in Neuro 2a mouse neuroblastoma cells.

Tetrandrine (TET), a plant alkaloid, is known primarily as a non-selective Ca(2+) channel blocker. On the contrary to the cytoprotective effect on ischemia/reperfusion injury, TET has also been reported to cause cytotoxicity. In this study, we wished to understand the apparently disparate effects of this potential drug and thus investigated molecular mechanisms on proliferation and apoptosis and its effect on oxidative stress-induced apoptosis in Neuro 2a mouse neuroblastoma cells. We showed that TET, at high concentrations, induced cell cycle arrest and apoptosis through oxidative stress with following observations. Firstly, 10 microM TET elevated the reactive oxygen species (ROS) level and accordingly depleted glutathione (GSH) content. Secondly, pretreatment with antioxidants (NAC or GSH) protected cells from TET-induced apoptosis. We also demonstrated that treatment with 10 microM TET caused not only induction of p53, p21(waf1), and Bax, but also nuclear translocation of p53 and hypo-phosphorylation of pRb concurrently. Our important finding is that the concentration-dependent dual effect of TET, either inhibiting or promoting cell death induced by H(2)O(2) was observed, probably through regulating redox balance, which was well reflected on the GSH content in each condition. Besides, inhibition of Ca(2+) influx protected cells from H(2)O(2)-induced apoptosis even in the presence of 10 microM TET. Taken together, our data suggest that TET regulation of cellular redox states may play a major role in its dual action of cytotoxicity and cytoprotection.

ATP stimulates glucose transport through activation of P2 purinergic receptors in C(2)C(12) skeletal muscle cells.

Extracellular ATP acts as a signal that regulates a variety of cellular processes via binding to P2 purinergic receptors (P2 receptors). We herein investigated the effects and signaling pathways of ATP on glucose uptake in C(2)C(12) skeletal muscle cells. ATP as well as P2 receptor agonists (ATP-gamma S) stimulated the rate of glucose uptake, while P2 receptor antagonists (suramin) inhibited the stimulatory effect of ATP, indicating that P2 receptors are involved. This ATP-stimulated glucose transport was blocked by specific inhibitors of Gi protein (pertusiss toxin), phospholipase C (U73122), protein kinase C (GF109203X), and phosphatidylinositol (PI) 3-kinase (LY294002). ATP stimulated PI 3-kinase activity and P2 receptor antagonists blocked this activation. In C(2)C(12) myotubes expressing glucose transporter GLUT4, ATP increased basal and insulin-stimulated glucose transport. Finally, ATP facilitated translocation of GLUT1 and GLUT4 into plasma membrane. These results together suggest that cells respond to extracellular ATP to increase glucose transport through P2 receptors.