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2.
IEEE Trans Circuits Syst II Express Briefs ; 71(7): 3298-3302, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38961880

ABSTRACT

This brief presents an on-chip digital intensive frequency-locked loop (DFLL)-based wakeup timer with a time-domain temperature compensation featuring a embedded temperature sensor. The proposed compensation exploits the deterministic temperature characteristics of two complementary resistors to stabilize the timer's operating frequency across the temperature by modulating the activation time window of the two resistors. As a result, it achieves a fine trimming step (± 1 ppm), allowing a small frequency error after trimming (<± 20 ppm). By reusing the DFLL structure, instead of employing a dedicated sensor, the temperature sensing operates in the background with negligible power (2 %) and hardware overhead (< 1 %). The chip is fabricated in 40 nm CMOS, resulting in 0.9 pJ/cycle energy efficiency while achieving 8 ppm/ºC from -40ºC to 80ºC.

3.
Microsc Microanal ; 30(4): 635-649, 2024 Aug 21.
Article in English | MEDLINE | ID: mdl-38916533

ABSTRACT

Optimization of user-defined parameters (Dmax, Nmin, order (K)) in the Density-based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, used to characterize nanoclusters in Al-0.9% Mg-1.0% Si-0.3% Cu (mass %), was conducted. Ten combinations of parameters with a given K were considered for samples naturally aged (NA) and preaged (PA) at 100°C. We confirmed four types of unphysical clusters, artificially formed, by analyzing composition with size, atomic density, and atomic arrangement inside clusters. The optimum combinations minimizing those unphysical clusters were obtained for both NA and PA samples. Meanwhile, to evaluate the reliability of the optimum combination, volume rendering and isosurfacing were performed. As a result, regions of high solute concentration were confirmed, and those regions are in good agreement with the position of the clusters obtained by applying the optimum combination in DBSCAN. Furthermore, by comparing the optimum combinations with the fixed parameters widely used until now, we showed that for each dataset, considering independent parameters obtained in the same method is desirable rather than using fixed parameters. Consequently, an idea of determining the algorithm parameters for characterizing the nanoclusters in Al-Mg-Si(-Cu) alloys was introduced.

4.
PLoS One ; 19(5): e0303758, 2024.
Article in English | MEDLINE | ID: mdl-38768136

ABSTRACT

Nitric oxide (NO) promotes angiogenesis via various mechanisms; however, the effective transmission of NO in ischemic diseases is unclear. Herein, we tested whether NO-releasing nanofibers modulate therapeutic angiogenesis in an animal hindlimb ischemia model. Male wild-type C57BL/6 mice with surgically-induced hindlimb ischemia were treated with NO-releasing 3-methylaminopropyltrimethoxysilane (MAP3)-derived or control (i.e., non-NO-releasing) nanofibers, by applying them to the wound for 20 min, three times every two days. The amount of NO from the nanofiber into tissues was assessed by NO fluorometric assay. The activity of cGMP-dependent protein kinase (PKG) was determined by western blot analysis. Perfusion ratios were measured 2, 4, and 14 days after inducing ischemia using laser doppler imaging. On day 4, Immunohistochemistry (IHC) with F4/80 and gelatin zymography were performed. IHC with CD31 was performed on day 14. To determine the angiogenic potential of NO-releasing nanofibers, aorta-ring explants were treated with MAP3 or control fiber for 20 min, and the sprout lengths were examined after 6 days. As per either LDPI (Laser doppler perfusion image) ratio or CD31 capillary density measurement, angiogenesis in the ischemic hindlimb was improved in the MAP3 nanofiber group; further, the total nitrate/nitrite concentration in the adduct muscle increased. The number of macrophage infiltrations and matrix metalloproteinase-9 (MMP-9) activity decreased. Vasodilator-stimulated phosphoprotein (VASP), one of the major substrates for PKG, increased phosphorylation in the MAP3 group. MAP3 nanofiber or NO donor SNAP (s-nitroso-n-acetyl penicillamine)-treated aortic explants showed enhanced sprouting in an ex vivo aortic ring assay, which was partially abrogated by KT5823, a potent inhibitor of PKG. These findings suggest that the novel NO-releasing nanofiber, MAP3 activates PKG and promotes therapeutic angiogenesis in response to hindlimb ischemia.


Subject(s)
Cyclic GMP-Dependent Protein Kinases , Hindlimb , Ischemia , Mice, Inbred C57BL , Nanofibers , Neovascularization, Physiologic , Nitric Oxide , Animals , Nanofibers/chemistry , Male , Nitric Oxide/metabolism , Ischemia/drug therapy , Ischemia/metabolism , Cyclic GMP-Dependent Protein Kinases/metabolism , Mice , Hindlimb/blood supply , Neovascularization, Physiologic/drug effects , Matrix Metalloproteinase 9/metabolism , Phosphoproteins/metabolism , Microfilament Proteins/metabolism , Cell Adhesion Molecules
5.
Small ; 20(8): e2304999, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37821412

ABSTRACT

Rapid and precise acute myocardial infarction (AMI) diagnosis is essential for preventing patient death. In addition, the complementary roles of creatine kinase muscle brain (CK-MB) and cardiac troponin I (cTnI) cardiac biomarkers in the early and late stages of AMI demand their simultaneous detection, which is difficult to implement using conventional fluorescence and electrochemical technologies. Here, a nanotechnology-based one-stop immuno-surface-enhanced Raman scattering (SERS) detection platform is reported for multiple cardiac indicators for the rapid screening and progressive tracing of AMI events. Optimal SERS is achieved using optical property-based, excitation wavelength-optimized, and high-yield anisotropic plasmonic gold nanocubes. Optimal immunoassay reaction efficiencies are achieved by increasing immobilized antibodies. Multiple simultaneous detection strategies are implemented by incorporating two different Raman reports with narrow wavenumbers corresponding to two indicators and by establishing a computational SERS mapping process to accurately detect their concentrations, irrespective of multiple enzymes in the human serum. The SERS platform precisely estimated AMI onset and progressive timing in human serum and made rapid AMI identification feasible using a portable Raman spectrometer. This integrated platform is hypothesized to significantly contribute to emergency medicine and forensic science by providing timely treatment and observation.


Subject(s)
Myocardial Infarction , Humans , Creatine Kinase, MB Form , Myocardial Infarction/diagnosis , Troponin I , Biomarkers , Immunoassay
6.
Viruses ; 16(1)2023 12 21.
Article in English | MEDLINE | ID: mdl-38275951

ABSTRACT

Enterovirus A71 (EV71), coxsackievirus A16 (CVA16), and coxsackievirus B3 (CVB3) are pathogenic members of the Picornaviridae family that cause a range of diseases, including severe central nervous system complications, myocarditis, and pancreatitis. Despite the considerable public health impact of these viruses, no approved antiviral treatments are currently available. In the present study, we confirmed the potential of saucerneol, a compound derived from Saururus chinensis, as an antiviral agent against EV71, CVA16, and CVB3. In the in vivo model, saucerneol effectively suppressed CVB3 replication in the pancreas and alleviated virus-induced pancreatitis. The antiviral activity of saucerneol is associated with increased mitochondrial ROS (mROS) production. In vitro inhibition of mROS generation diminishes the antiviral efficacy of saucerneol. Moreover, saucerneol treatment enhanced the phosphorylation of STING, TBK-1, and IRF3 in EV71- and CVA16-infected cells, indicating that its antiviral effects were mediated through the STING/TBK-1/IRF3 antiviral pathway, which was activated by increased mROS production. Saucerneol is a promising natural antiviral agent against EV71, CVA16, and CVB3 and has potential against virus-induced pancreatitis and myocarditis. Further studies are required to assess its safety and efficacy, which is essential for the development of effective antiviral strategies against these viruses.


Subject(s)
Enterovirus A, Human , Enterovirus Infections , Enterovirus , Myocarditis , Pancreatitis , Saururaceae , Humans , Reactive Oxygen Species/metabolism , Myocarditis/drug therapy , Enterovirus Infections/drug therapy , Antigens, Viral/metabolism , Antiviral Agents/pharmacology , Pancreatitis/drug therapy , Saururaceae/metabolism , Interferon Regulatory Factor-3/metabolism
7.
Behav Sci (Basel) ; 12(11)2022 Nov 11.
Article in English | MEDLINE | ID: mdl-36421739

ABSTRACT

As the business environment is rapidly changing, interest in the innovation of organizational members is accelerating. Therefore, this study investigated how individual-level resources, particularly self-leadership, affect workers' innovative behavior. Many studies have emphasized that employee initiative can lead to job performance at the individual level and organizational performance improvement. Self-leadership is a spontaneous and an active behavior, or mindset, defined as the ability to lead an individual in challenging situations characterized by learned behaviors that can be augmented by training. It is of interest to many researchers and practitioners. Further, we tested the mediation of informal learning, another individual-level resource, in this relationship and the moderation of social capital, a social resource, in the mediation. We analyzed the responses of 551 employees of South Korean companies using Model 6 and 14 of PROCESS Macro. The results revealed that self-leadership positively influenced workers' innovative behavior, and informal learning mediated this relationship. We also confirmed that social capital strengthened the positive mediating effect of informal learning. This study empirically verifies the role of self-leadership, informal learning, and social capital as the determinants of innovative behavior and expands the discussion on leadership by highlighting the significance of self-leadership as opposed to traditional leadership approaches.

8.
Life (Basel) ; 12(2)2022 Jan 28.
Article in English | MEDLINE | ID: mdl-35207485

ABSTRACT

Dyslipidemia, the commonest cause of cardiovascular disease, leads to lipid deposits on the arterial wall, thereby aggravating atherosclerosis. DSHT (Daeshiho-tang) has long been used as an anti-dyslipidemia agent in oriental medicine. However, the anti-atherosclerotic effects of DSHT have not been fully investigated. Therefore, this study was designed to evaluate whether DSHT could exert beneficial anti-atherosclerotic effects. We fed apolipoprotein E-deficient (ApoE-/-) mice on a high-fat diet and treated them with atorvastatin (AT) or DSHT, or the combination of DSHT and AT for 12 weeks. To determine the role of DSHT, atherosclerotic lesions in the aorta, aortic root, and aortic arch; lipids and apolipoprotein levels in serum; and macrophage polarization markers in aorta tissues were examined. We show here that the DSHT decreased the atherosclerotic plaque ratio in the aortic arch, aorta, and aortic root. DSHT also regulated lipid levels by decreasing the ApoB level and increasing the ApoA1 level. Moreover, DSHT effectively regulated cholesterol metabolism by increasing the levels of PPARγ, ABCA1 and ABCG1, and the LDL receptor genes. We further found that DSHT promoted polarization to the M2 phenotype by increasing the levels of M2 macrophage (ARG1, CD163, and PPARγ) markers. Our data suggested that DSHT enhances the anti-atherosclerotic effect by regulating cholesterol metabolism through the activation of the PPARγ signaling pathway and by promoting anti-inflammatory M2 macrophage polarization.

10.
IEEE Trans Microw Theory Tech ; 70(10): 4579-4589, 2022 Aug 22.
Article in English | MEDLINE | ID: mdl-36846311

ABSTRACT

A digital-impulse galvanic coupling as a new high-speed trans-dural (from cortex to the skull) data transmission method has been presented in this paper. The proposed wireless telemetry replaces the tethered wires connected in between implants on the cortex and above the skull, allowing the brain implant to be "free-floating" for minimizing brain tissue damage. Such trans-dural wireless telemetry must have a wide channel bandwidth for high-speed data transfer and a small form factor for minimum invasiveness. To investigate the propagation property of the channel, a finite element model is developed and a channel characterization based on a liquid phantom and porcine tissue is performed. The results show that the trans-dural channel has a wide frequency response of up to 250 MHz. Propagation loss due to micro-motion and misalignments is also investigated in this work. The result indicates that the proposed transmission method is relatively insensitive to misalignment. It has approximately 1 dB extra loss when there is a horizontal misalignment of 1mm. A pulse-based transmitter ASIC and a miniature PCB module are designed and validated ex-vivo with a 10-mm thick porcine tissue. This work demonstrates a high-speed and miniature in-body galvanic-coupled pulse-based communication with a data rate up to 250 Mbps with an energy efficiency of 2 pJ/bit, and has a small module area of only 26 mm2.

11.
IEEE J Solid-State Circuits ; 57(12): 3656-3668, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36743394

ABSTRACT

This paper presents an implantable impulse-radio ultra-wideband (IR-UWB) wireless telemetry system for intracortical neural sensing interfaces. A 3-dimensional (3-D) hybrid impulse modulation that comprises phase shift keying (PSK), pulse position modulation (PPM) and pulse amplitude modulation (PAM) is proposed to increase modulation order without significantly increasing the demodulation requirement, thus leading to a high data rate of 1.66 Gbps and an increased air-transmission range. Operating in 6 - 9 GHz UWB band, the presented transmitter (TX) supports the proposed hybrid modulation with a high energy efficiency of 5.8 pJ/bit and modulation quality (EVM< -21 dB). A low-noise injection-locked ring oscillator supports 8-PSK with a phase error of 2.6°. A calibration free delay generator realizes a 4-PPM with only 115 µW and avoids potential cross-modulation between PPM and PSK. A switch-cap power amplifier with an asynchronous pulse-shaping performs 4-PAM with high energy efficiency and linearity. The TX is implemented in 28 nm CMOS technology, occupying 0.155mm2 core area. The wireless module including a printed monopole antenna has a module area of only 1.05 cm2. The transmitter consumes in total 9.7 mW when transmitting -41.3 dBm/MHz output power. The wireless telemetry module has been validated ex-vivo with a 15-mm multi-layer porcine tissue, and achieves a communication (air) distance up to 15 cm, leading to at least 16× improvement in distance-moralized energy efficiency of 45 pJ/bit/meter compared to state-of-the-art.

12.
Am J Cardiovasc Drugs ; 22(2): 117-125, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34151411

ABSTRACT

The anti-cancer agent doxorubicin (DOX) has high cardiotoxicity that is linked to DOX-mediated increase in oxidative stress, mitochondrial iron overload, DNA damage, autophagy, necrosis, and apoptosis, all of which are also associated with secondary tumorigenicity. This limits the clinical application of DOX therapies. Previous studies have attributed DOX-mediated cardiotoxicity to mitochondrial iron accumulation and the production of reactive oxygen species (ROS), which seem to be independent of its anti-tumor DNA damaging effects. Chemo-sensitization of soluble guanylate cyclase (sGC) in the cyclic guanosine monophosphate (cGMP) pathway induces tumor cell death despite the cardiotoxicity associated with DOX treatment. However, sGC-cGMP signaling must be activated during heart failure to facilitate myocardial cell survival. The sGC pathway is dependent on nitric oxide and signal transduction via the nitric oxide-sGC-cGMP pathway and is attenuated in various cardiovascular diseases. Additionally, cGMP signaling is regulated by the action of certain phosphodiesterases (PDEs) that protect the heart by inhibiting PDE, an enzyme that hydrolyses cGMP to GMP activity. In this review, we discuss the studies describing the interactions between cGMP regulation and DOX-mediated cardiotoxicity and their application in improving DOX therapeutic outcomes. The results provide novel avenues for the reduction of DOX-induced secondary tumorigenicity and improve cellular autonomy during DOX-mediated cardiotoxicity.


Subject(s)
Cyclic GMP , Heart Failure , Cyclic GMP/metabolism , Cyclic GMP/pharmacology , Doxorubicin/adverse effects , Heart Failure/chemically induced , Heart Failure/drug therapy , Humans , Signal Transduction , Soluble Guanylyl Cyclase/metabolism , Soluble Guanylyl Cyclase/pharmacology
13.
FASEB J ; 35(1): e21225, 2021 01.
Article in English | MEDLINE | ID: mdl-33337568

ABSTRACT

Studies of neuroglial interaction largely depend on cell-specific gene knockout (KO) experiments using Cre recombinase. However, genes known as glial-specific genes have recently been reported to be expressed in neuroglial stem cells, leading to the possibility that a glia-specific Cre driver results in unwanted gene deletion in neurons, which may affect sound interpretation. 2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNP) is generally considered to be an oligodendrocyte (OL) marker. Accordingly, Cnp promoter-controlled Cre recombinase has been used to create OL-specific gene targeting mice. However, in this study, using Rosa26-tdTomato-reporter/Cnp-Cre mice, we found that many forebrain neurons and cerebellar Purkinje neurons belong to the lineages of Cnp-expressing neuroglial stem cells. To answer whether gene targeting by Cnp-Cre can induce neuron-autonomous defects, we conditionally deleted an essential autophagy gene, Atg7, in Cnp-Cre mice. The Cnp-Cre-mediated Atg7 KO mice showed extensive p62 inclusion in neurons, including cerebellar Purkinje neurons with extensive neurodegeneration. Furthermore, neuronal areas showing p62 inclusion in Cnp-Cre-mediated Atg7 KO mice overlapped with the neuronal lineage of Cnp-expressing neuroglial stem cells. Moreover, Cnp-Cre-mediated Atg7-KO mice did not develop critical defects in myelination. Our results demonstrate that a large population of central neurons are derived from Cnp-expressing neuroglial stem cells; thus, conditional gene targeting using the Cnp promoter, which is known to be OL-specific, can induce neuron-autonomous phenotypes.


Subject(s)
2',3'-Cyclic Nucleotide 3'-Phosphodiesterase/deficiency , Neurodegenerative Diseases/enzymology , Neuroglia/enzymology , Purkinje Cells/enzymology , Stem Cells/enzymology , 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase/metabolism , Animals , Autophagy-Related Protein 7/genetics , Integrases/genetics , Integrases/metabolism , Mice , Mice, Knockout , Neurodegenerative Diseases/genetics , Neurodegenerative Diseases/pathology , Neuroglia/pathology , Purkinje Cells/pathology , Stem Cells/pathology
14.
Int J Mol Sci ; 21(24)2020 Dec 15.
Article in English | MEDLINE | ID: mdl-33333928

ABSTRACT

In brain ischemia, oxidative stress induces neuronal apoptosis, which is mediated by increased activity of the voltage-gated K+ channel Kv2.1 and results in an efflux of intracellular K+. The molecular mechanisms underlying the regulation of Kv2.1 and its activity during brain ischemia are not yet fully understood. Here this study provides evidence that oxidant-induced apoptosis resulting from brain ischemia promotes rapid tyrosine phosphorylation of Kv2.1. When the tyrosine phosphorylation sites Y124, Y686, and Y810 on the Kv2.1 channel are mutated to non-phosphorylatable residues, PARP-1 cleavage levels decrease, indicating suppression of neuronal cell death. The tyrosine residue Y810 on Kv2.1 was a major phosphorylation site. In fact, cells mutated Y810 were more viable in our study than were wild-type cells, suggesting an important role for this site during ischemic neuronal injury. In an animal model, tyrosine phosphorylation of Kv2.1 increased after ischemic brain injury, with an observable sustained increase for at least 2 h after reperfusion. These results demonstrate that tyrosine phosphorylation of the Kv2.1 channel in the brain may play a critical role in regulating neuronal ischemia and is therefore a potential therapeutic target in patients with brain ischemia.


Subject(s)
Apoptosis/genetics , Brain Ischemia/metabolism , Shab Potassium Channels/metabolism , Tyrosine/metabolism , 2,2'-Dipyridyl/analogs & derivatives , 2,2'-Dipyridyl/pharmacology , Animals , Apoptosis/drug effects , Brain Ischemia/genetics , Cell Survival/drug effects , Cell Survival/genetics , Disulfides/pharmacology , HEK293 Cells , Humans , Immunohistochemistry , Male , Mice , Mice, Inbred C57BL , Mutation , Neurons/drug effects , Neurons/metabolism , Oxidative Stress/drug effects , Phosphorylation , Poly (ADP-Ribose) Polymerase-1/metabolism , Rats , Shab Potassium Channels/genetics
15.
IEEE Trans Biomed Circuits Syst ; 14(6): 1218-1229, 2020 12.
Article in English | MEDLINE | ID: mdl-33170783

ABSTRACT

This paper presents a millimeter-scale crystal-less wireless transceiver for volume-constrained insertable pills. Operating in the 402-405 MHz medical implant communication service (MICS) band, the phase-tracking receiver-based over-the-air carrier recovery has a ±160 ppm coverage. A fully integrated adaptive antenna impedance matching solution is proposed to calibrate the antenna impedance variation inside the body. A tunable matching network (TMN) with single inductor performs impedance matching for both transmitter (TX) and receiver (RX) and TX/RX mode switching. To dynamically calibrate the antenna impedance variation over different locations and diet conditions, a loop-back power detector using self-mixing is adopted, which expands the power contour up to 4.8 VSWR. The transceiver is implemented in a 40-nm CMOS technology, occupying 2 mm2 die area. The transceiver chip and a miniature antenna are integrated in a 3.5 × 15 mm2 area prototype wireless module. It has a receiver sensitivity of -90 dBm at 200 kbps data rate and delivers up to - 25 dBm EIRP in the wireless measurement with a liquid phantom.


Subject(s)
Electronics, Medical/instrumentation , Gastroscopy/instrumentation , Wireless Technology/instrumentation , Equipment Design , Humans , Models, Biological , Phantoms, Imaging , Signal Processing, Computer-Assisted/instrumentation , Stomach/diagnostic imaging
16.
Chem Biol Interact ; 328: 109190, 2020 Sep 01.
Article in English | MEDLINE | ID: mdl-32652078

ABSTRACT

BACKGROUND: Doxorubicin (DOX) administration decreases cardiac soluble guanylate cyclase (sGC) activity. We hypothesized that bypassing impaired NO-sGC-cGMP pathway resulting from the activation of oxidized and heme-free soluble guanylate cyclase (sGC) could be a therapeutic target for DOX-mediated cardiomyopathy (DOX-CM). The present study investigated the therapeutic roles and mechanism of BAY60-2770, an activator of oxidized sGC, in alleviating DOX-CM. METHODS: H9c2 cardiomyocytes were pretreated with BAY60-2770 followed by DOX. Cell viability and intracellular reactive oxygen species (ROS) were subsequently measured. To determine the role BAY60-2770 in mitochondrial ROS generation and mitochondrial membrane potential, we examined mitoSOX RED and TMRE fluorescence under DOX exposure. As animal experiments, rats were orally administered with 5 mg/kg of BAY60-2770 at 1 h prior to every DOX treatment and then assessed by echocardiography and apoptotic marker and autophagy. RESULTS: BAY60-2770 ameliorated cell viability and DOX-induced oxidative stress in H9c2 cells, which was mediated by PKG activation. Mitochondrial ROS and TMRE fluorescence were attenuated by BAY60-2770 in DOX-treated H9c2 cells. DOX-induced caspase-3 activation decreased after pretreatment with BAY60-2770 in vivo and in vitro. Echocardiography showed that BAY60-2770 significantly improved DOX-induced myocardial dysfunction. Autophagosome was increased by BAY60-2770 in vivo. CONCLUSIONS: BAY60-2770 appears to mitigate DOX-induced mitochondrial ROS, membrane potential loss, autophagy, and subsequent apoptosis, leading to protection of myocardial injury and dysfunction. These novel results highlighted the therapeutic potential of BAY60-2770 in preventing DOX-CM.


Subject(s)
Autophagy/drug effects , Benzoates/pharmacology , Biphenyl Compounds/pharmacology , Cardiotoxicity/pathology , Doxorubicin/adverse effects , Hydrocarbons, Fluorinated/pharmacology , Oxidative Stress/drug effects , Animals , Apoptosis/drug effects , Cell Line , Male , Membrane Potential, Mitochondrial/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Rats, Sprague-Dawley , Reactive Oxygen Species/metabolism
17.
J Nanosci Nanotechnol ; 20(1): 540-545, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31383207

ABSTRACT

Two types of nanoclusters were detected using DSC thermal analysis operating at -50 °C with liquid nitrogen. The formation of Cluster (1) was substantially suppressed by the formation of Cluster (2) during step quenching at 100 °C for 0.06 ks. The hardness increase was retarded for a period during two-step aging at 170 °C in the case of natural aging for 604.8 ks. The hardness decrease was determined to be due to the dissolution of nanoclusters in the early stage of two-step aging at 170 °C. On the other hand, hardness was directly increased in the step-quenched samples during multi-step aging at 170 °C. It is noted that Cluster (2) directly transforms into the strengthening phase. The bake hardening response is fairly enhanced by the formation of Cluster (2), which is formed by the step quenching process. It was confirmed that the step-quenched samples had a higher number of precipitates than the naturally-aged ones based on TEM images. The structure of the precipitate was identified to be the ß″ phase by analyzing HRTEM image.

18.
Mol Cells ; 42(9): 637-645, 2019 Sep 30.
Article in English | MEDLINE | ID: mdl-31564075

ABSTRACT

Effector-triggered immunity (ETI) is an effective layer of plant defense initiated upon recognition of avirulence (Avr) effectors from pathogens by cognate plant disease resistance (R) proteins. In rice, a large number of R genes have been characterized from various cultivars and have greatly contributed to breeding programs to improve resistance against the rice blast pathogen Magnaporthe oryzae. The extreme diversity of R gene repertoires is thought to be a result of co-evolutionary history between rice and its pathogens including M. oryzae. Here we show that Pii is an allele of Pi5 by DNA sequence characterization and complementation analysis. Pii-1 and Pii-2 cDNAs were cloned by reverse transcription polymerase chain reaction from the Pii -carrying cultivar Fujisaka5 . The complementation test in susceptible rice cultivar Dongjin demonstrated that the rice blast resistance mediated by Pii , similar to Pi5 , requires the presence of two nucleotide-binding leucine-rich repeat genes, Pii-1 and Pii-2 . Consistent with our hypothesis that Pi5 and Pii are functionally indistinguishable, the replacement of Pii-1 by Pi5-1 and Pii-2 by Pi5-2 , respectively, does not change the level of disease resistance to M. oryzae carrying AVR-Pii. Surprisingly, Exo70F3, required for Pii-mediated resistance, is dispensable for Pi5-mediated resistance. Based on our results, despite similarities observed between Pi5 and Pii, we hypothesize that Pi5 and Pii pairs require partially distinct mechanisms to function.


Subject(s)
Disease Resistance/genetics , Genes, Plant , Magnaporthe/physiology , NLR Proteins/metabolism , Oryza/microbiology , Plant Diseases/microbiology , Base Sequence , CRISPR-Cas Systems/genetics , DNA, Complementary/genetics , Gene Expression Regulation, Plant , Mutation/genetics , Oryza/genetics , Plants, Genetically Modified
19.
Ann Clin Transl Neurol ; 6(7): 1292-1301, 2019 07.
Article in English | MEDLINE | ID: mdl-31353867

ABSTRACT

OBJECTIVE: Myelinated Schwann cells (SCs) in adult peripheral nerves dedifferentiate into immature cells in demyelinating neuropathies and Wallerian degeneration. This plastic SC change is actively involved in the myelin destruction and clearance as demyelinating SCs (DSCs). In inherited demyelinating neuropathy, pathologically differentiated and dysmyelinated SCs constitute the main nerve pathology. METHODS: We investigated whether this SC plastic status in human neuropathic nerves could be determined by patient sera to develop disease-relevant serum biomarkers. Based on proteomics analysis of the secreted exosomes from immature SCs, we traced p75 neurotrophin receptor (p75) and neural cell adhesion molecule 1 (NCAM) in the sera of patients with peripheral neuropathy. RESULTS: Enzyme-linked immunosorbent assay (ELISA) revealed that p75 and NCAM were subtype-specifically expressed in the sera of patients with peripheral neuropathy. In conjunction with these ELISA data, pathological analyses of animal models and human specimens suggested that the presence of DSCs in inflammatory neuropathy and of supernumerary nonmyelinating or dysmyelinating SCs in inherited neuropathy could potentially be distinguished by comparing the expression profiles of p75 and NCAM. INTERPRETATION: This study indicates that the identification of disease-specific pathological SC stages might be a valuable tool for differential diagnosis of peripheral neuropathies.


Subject(s)
CD56 Antigen/metabolism , Nerve Tissue Proteins/metabolism , Peripheral Nervous System Diseases/metabolism , Receptors, Nerve Growth Factor/metabolism , Schwann Cells/metabolism , Animals , CD56 Antigen/blood , Demyelinating Diseases/metabolism , Female , Humans , Male , Mice, Inbred C57BL , Myelin Sheath/metabolism , Myelin Sheath/pathology , Nerve Tissue Proteins/blood , Peripheral Nervous System Diseases/blood , Receptors, Nerve Growth Factor/blood , Schwann Cells/pathology
20.
Parkinsonism Relat Disord ; 66: 143-150, 2019 09.
Article in English | MEDLINE | ID: mdl-31353306

ABSTRACT

INTRODUCTION: Most cases of Parkinson's disease (PD) are sporadic, but genetic variations have been discovered in PD patients. PARK7/DJ-1 is a known cause of early-onset autosomal-recessive PD and is implicated in neuroprotection against oxidative stress. Although several post-translational modifications of DJ-1 have been proposed, phospho-modification of DJ-1 and its functional consequences have been less studied. METHODS: Putative phosphorylation sites of DJ-1 were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS analysis). Subsequently, phosphorylation site of DJ-1 was confirmed by in vitro kinase assay and cell-based pull-down assay. Impaired dimer formation of phospho-null mutant was measured using DSS crosslinking assay and immunoprecipitation assay. To evaluate physiological consequences of this event, protein stability of DJ-1 WT and DJ-1 phospho-null mutant were compared using cycloheximide chase assay and ubiquitination assay. RESULTS: Here, we showed that DJ-1 directly bound to the catalytic subunit of protein kinase A (PKAcα). We found that PKAcα is responsible for phosphorylation of DJ-1 at the T154 residue. Interestingly, dimerization of DJ-1 was not detected in a DJ-1 T154A mutant. Furthermore, stability of the DJ-1 T154A mutant was dramatically reduced compared with that of wild-type DJ-1. We found that DJ-1 T154A was prone to degradation by the ubiquitin proteasome system (UPS). CONCLUSION: We identified a novel phosphorylation site of DJ-1. Furthermore, we determined protein kinase A that is responsible for this posttranslational modification. Finally, we demonstrated physiological consequences of this event focusing on dimerization and protein stability of DJ-1.


Subject(s)
Cyclic AMP-Dependent Protein Kinases/metabolism , Parkinson Disease/metabolism , Protein Deglycase DJ-1/metabolism , Chromatography, Liquid , HEK293 Cells , Humans , Phosphorylation/physiology , Protein Stability , Tandem Mass Spectrometry
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