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New Mn Electrochemistry for Rechargeable Aqueous Batteries: Promising Directions Based on Preliminary Results
No full textAqueous batteries with metal anodes exhibit robust anodic capacities, but their energy densities are low because of the limited potential stabilities of aqueous electrolyte solutions. Current metal options, such as Zn and Al, pose a dilemma: Zn lacks a sufficiently low redox potential, whereas Al tends to be strongly oxidized in aqueous environments. Our investigation introduces a novel rechargeable aqueous battery system based on Mn as the anode. We examine the effects of anions, electrolyte concentration, and diverse cathode chemistries. Notably, the ClO4-based electrolyte solution exhibits improved deposition and dissolution efficiencies. Although stainless steel (SS 316 L) and Ni are stable current collectors for cathodes, they display limitations as anodes. However, using Ti as the anode resulted in increased Mn deposition and dissolution efficiencies. Moreover, we evaluate this system using various cathode materials, including Mn-intercalation-based inorganic (Ag0.33V2O5) and organic (perylenetetracarboxylic dianhydride) cathodes and an anion-intercalation-chemistry (coronene)-based cathode. These configurations yield markedly higher output potentials compared to those of Zn metal batteries, highlighting the potential for an augmented energy density when using an Mn anode. This study outlines a systematic approach for use in optimizing metal anodes in Mn metal batteries, unlocking novel prospects for Mn-based batteries with diverse cathode chemistries. © 2024 The Author(s). Energy & Environmental Materials published by John Wiley & Sons Australia, Ltd on behalf of Zhengzhou University.TRUEsciescopu
Mitochondrial-targeted therapies in traumatic brain injury: From bench to bedside
No full textTraumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide, with limited effective therapeutic options currently available. Recent research has highlighted the pivotal role of mitochondrial dysfunction in the pathophysiology of TBI, making mitochondria an attractive target for therapeutic intervention. This review comprehensively examines advancements in mitochondrial-targeted therapies for TBI, bridging the gap from basic research to clinical applications. We discuss the underlying mechanisms of mitochondrial damage in TBI, including oxidative stress, impaired bioenergetics, mitochondrial dynamics, and apoptotic pathways. Furthermore, we highlight the complex interplay between mitochondrial dysfunction, inflammation, and blood-brain barrier (BBB) integrity, elucidating how these interactions exacerbate injury and impede recovery. We also evaluate various preclinical studies exploring pharmacological agents, gene therapy, and novel drug delivery systems designed to protect and restore mitochondrial function. Clinical trials and their outcomes are assessed to evaluate the translational potential of mitochondrial-targeted therapies in TBI. By integrating findings from bench to bedside, this review emphasizes promising therapeutic avenues and addresses remaining challenges. It also provides guidance for future research to pave the way for innovative treatments that improve patient outcomes in TBI. © 2024 The Author(s)TRUEsciescopu
Selective conversion of CO2 to CO using blue TiO2 with an r-GO shell and quantitative measurement of excited electrons with four-wave mixing microspectroscopy
No full textThe conversion of CO2 into hydrocarbon or syngas (CO) using sunlight can address numerous current environmental issues and future challenges in the energy domain. Although numerous visible light-responsive photocatalysts have been reported, the quantum yield remains limited. Furthermore, analytical tools are yet to be established for quantitatively monitoring the amount of excited electrons, which play a critical role in catalytic reactions. The results of this study revealed that the presence of a reduced graphene oxide (r-GO) shell on blue-TiO2 (b-TiO2) considerably improves the photocatalytic performance in selectively converting CO2 into CO under visible light. The formation of the r-GO shell on b-TiO2 narrowed the b-TiO2 bandgap. Moreover, the r-GO shell increased the absorption of visible light and facilitated electron transfer, resulting in approximately eight times the CO yield from b-TiO2@r-GO compared to that of TiO2. The presence of the r-GO shell improved the photocatalytic stability of b-TiO2. Furthermore, four-wave mixing microspectroscopy was performed to analyze the amount of excited electrons. The results of microscopy revealed the amount of excited electrons in b-TiO2@r-GO was approximately 35 times that of TiO2. These results not only proposed a strategy for increasing the stability and efficiency of TiO2-based photocatalysts but also are useful for evaluating the improvement of photocatalyst materials. © 2024 Elsevier LtdFALSEsciescopu
Effect of incorporated transition metals on the adsorption mechanisms of radioactive cesium in Prussian blue analogs
No full textExtensive efforts were made to remove radioactive cesium (137Cs) from the environment, with Prussian blue analogs (PBAs) emerging as highly selective and efficient materials for 137Cs removal. However, limited studies systematically compared Cs+ adsorption across different transition metals in PBA. This study investigates the influence of the choice of transition metal ion (Co, Cu, Fe, Mn, Ni, Zn) on Cs+ adsorption mechanisms and efficiency. PBAs were synthesized and characterized based on their specific surface area, ion exchange capacity, lattice parameter, and defect sites (as indicated by water molecule content). Cs+ adsorption mechanisms varied significantly with transition metals. In CoFe and FeFe PBAs, ion exchange with K+ dominated, while CuFe and MnFe PBAs, with more defect sites primarily used ion exchange between H+ and Cs+. NiFe and ZnFe exhibited enhanced Cs+ adsorption under light irradiation, likely due to their light-absorbing properties facilitating a reduction reaction. The Langmuir adsorption isotherm was applied to model the adsorption behavior, confirming that each performance of PBA depends on the transition metal used. These findings suggest that PBAs with various transition metals can efficiently remove 137Cs under diverse environmental conditions by using distinct adsorption mechanisms. © 2024 Elsevier LtdFALSEsciescopu
MoS2 nanoflowers surface decorated with CuS nanorods and carbon dots for fluorescent and ultrasound imaging in cancer therapy
No full textIn recent years, the design of various ultrasound responsive echogenic nanomaterials offers many advantages such as deep tissue penetration, high signal intensity, colloidal stability, biocompatibility and less expensive for ultrasound-based cancer cell imaging while providing the option to monitor the progress of tumor volume during the treatment. Further, the ability of nanomaterials to combine photo-thermal therapy (PTT) and chemotherapy has opened a new avenue in the development of cancer theranostics for synergistic cancer therapy. Herein, we report MoS2 nanoflowers (NFs) surface decorated with CuS nanorods (NRs) and folic acid-derived carbon dots (FACDs) using cystine-polyethyleneimine (PEI) linker for PTT-chemotherapy. The size of NFs was found to be 350 ± 50 nm which increased to 500 ± 50 nm after surface decoration. The morphology of MoS2 NFs before and after surface decoration was investigated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-Vis-NIR spectroscopy. The photo-thermal heat generation was found to be increasing as a function of the concentration of NFs. The encapsulation efficiency of doxorubicin (DOX) and photo-thermal conversion efficiency (PCE) for surface-decorated MoS2 NFs (MoS2@CuS/FACDs NFs) was estimated to be 42 and 44 %, respectively. The surface decoration of CuS NRs and FACDs on MoS2 NFs not only improved the anticancer activity but also increased the signal intensity in ultrasound and fluorescence imaging of cancer cells. The MoS2@CuS/FACDs NFs exhibited excellent cytotoxicity against MDA-MB-231 cancer cells. Hence, the hybrid system demonstrated here showed high potential for use as a combined probe for non-invasive ultrasound imaging and fluorescence imaging for PTT-chemotherapy. © 2025 Elsevier B.V.FALSEsciescopu
불확실한 보상 조건에서의 생리적 도파민 신경 활성 역학
No full textDopamine signaling, Neural firing, Uncertain conditions, Different reward probabilities, An integrated opto-probe deviceⅠ. Introduction 1
Ⅱ. Methods 3
2.1 Animal 3
2.2 Surgical procedures 3
2.3 Behavioral task 3
2.4 Electrophysiology 4
2.5 Fiber photometry 6
2.6 Immunohistochemistry 6
2.7 Quantification and statistical analysis 7
Ⅲ. Results 9
3.1 Behavioral changes in response to different reward probabilities in a Pavlovian conditioning task 9
3.2 Classification and analysis of spiking activity in the ventral striatum 14
3.3 Influence of dopamine response and neural activation under probabilistic reward conditions 17
Ⅳ. Discussion 24
Ⅴ. Reference 26
Abstract in Korean 30MasterdCollectio
Blue photoluminescence from active carboxyl adatoms on nanoporous anodic alumina films
Get PDFNanoporous anodic alumina (nPAA) films formed on aluminum in lower aliphatic carboxylic acids exhibit blue self-coloring and characteristic properties such as photoluminescence (PL), electroluminescence, and electron spin resonance. The blue colors are seemingly originated from the adsorbed radicals incorporating into the oxide during the aluminum anodization. However, there is lack of reports revealing the detailed activation mechanism of the adatoms in the complexes. This study investigates the blue PL and its correlation with the atomic and electronic structures of the active aluminum surface using multiple theoretical and experimental methods. The results show that the concentration of carboxylates at the nPAA surface is highly correlated with the blue colorization and manifest that unpaired electrons in carbon (derived from the carboxylates) bridging two aluminum atoms at surface can play as an active source of the blue colorization. Therefore, it is suggested that controlling the adsorption of the carboxylate on the alumina membrane having large surface-to-volume ratio can be an efficient way to generate the blue light for the optoelectronic applications. © 2025. The Author(s).FALSEsciescopu
Mechanistic study of chronic unpredictable stress-induced autophagic death in adult hippocampal neural stem cells
No full textChronic unpredictable stress, autophagic cell death, adult hippocampal neural stem cells, Calpain 2, CorticosteroneChronic unpredictable stress (CUS) is an established model for inducing depressive-like behaviors and cognitive impairments, mirroring chronic stress effects in humans. This study examines the role of autophagy in CUS-induced behavioral and cellular responses, particularly its impact on hippocampal neural stem cells (NSCs). In Ctrl mice, CUS exposure led to significant anxiety-like behaviors, spatial memory deficits, and hippocampal NSC loss. NSC-specific conditional knockout of Atg7 (Atg7-NSC cKO) mice, however, were resistant to CUS and did not show depressive phenotypes. Elevated autophagy flux was observed in the NSCs of CUS-exposed Ctrl mice, correlating with increased formation of autophagosomes and autolysosomes, whereas autophagy was effectively suppressed in those of Atg7-NSC cKO mice, highlighting autophagy’s critical role in stress-induced NSC death and behavioral impairment. Additionally, corticosterone (CORT) induces calpain 2 degradation via the ubiquitin-proteasome system (UPS) and inhibition of calpain 2 promoted autophagy flux, accelerating autophagic cell death (ACD) in hippocampal NSCs. In our previous study, calpain was reported to shift ACD to apoptosis in insulin-deprived hippocampal NSCs, suggesting UPS-mediated degradation as a critical pathway switching cell death type in hippocampal NSCs. These findings suggest that autophagy and calpain critically determine NSC fate under stress, providing potential therapeutic avenue to protect against the harmful effects of chronic stress on the brain.
Keywords: Chronic unpredictable stress, autophagic cell death, adult hippocampal neural stem cells, Calpain 2, Corticosterone
|본 논문은 만성 예측불가능 스트레스(CUS)가 인간의 만성 스트레스 효과를 모방하여 우울증 유사 행동 및 인지 기능 장애를 유도하는 확립된 모델임을 기반으로, CUS에 의해 유도된 자가포식(autophagy)의 역할을 해마 신경줄기세포(NSC)에서 중점적으로 분석하였다. CUS 모델은 만성 스트레스의 다양한 행동적, 신경생물학적 영향을 반영하며, 본 연구는 자가포식이 CUS에 의한 해마 NSC의 기능 및 행동적 변화를 어떻게 조절하는지 그 메커니즘을 탐구하고자 하였다.
야생형(Ctrl) 생쥐에서 CUS에 노출될 경우, 불안 유사 행동, 공간 기억 손상 및 해마 NSC의 손실이 유의미하게 나타났다. 이는 인간의 만성 스트레스에 대한 반응과 유사하며, CUS가 신경 줄기세포의 생존 및 기능에 부정적인 영향을 미친다는 점을 확인하였다. 반면, NSC 특이적 조건부 Atg7 결손 마우스(Atg7-NSC cKO)는 CUS에 저항성을 보이며, 불안 및 우울증 관련 행동과 같은 스트레스 유발 행동이 유의미하게 감소하였다. 이는 Atg7이 CUS에 의해 유도되는 자가포식 경로 활성화와 연관되어 있으며, Atg7-NSC cKO 생쥐의 경우 자가포식이 억제되어 NSC의 사멸 및 행동적 결함이 감소하는 것을 확인했다.
CUS에 노출된 Ctrl 생쥐에서 자가포식 활성(autophagy flux)이 현저히 증가한 점은 자가포식체(autophagosome)와 자가용해체(autolysosome) 수의 증가로 나타났으며, 이는 자가포식이 스트레스 상황에서 NSC 사멸과 관련된 주요 메커니즘임을 시사한다. 반면, Atg7-NSC cKO 생쥐는 자가포식 경로가 억제되어 스트레스에 의한 NSC 손실과 행동 장애가 완화됨으로써, CUS에 의한 NSC 사멸과 행동 장애에서 자가포식의 역할이 강조된다.
또한, 스트레스 호르몬인 코르티코스테론(CORT)은 자가포식 경로가 아닌 유비퀴틴-프로테아좀 시스템(UPS)을 통해 calpain 2의 분해를 유도하는 것으로 나타났다. CORT에 의해 calpain 2가 억제된 해마 NSC에서는 자가포식 활성이 촉진되어 자가포식 세포사멸(autophagic cell death, ACD)이 가속화되는 경향을 보였다. 이는 CORT이 calpain 2의 UPS를 통한 분해를 조절하여 자가포식 활성에 영향을 미치는 기전임을 시사한다. 이전 연구에서는 calpain이 인슐린 결핍 상태에서 ACD를 apoptosis로 전환시키는 중요한 역할을 한다고 보고되었으며, 이는 UPS에 의한 calpain 2 분해가 해마 NSC에서 세포 사멸 유형을 전환하는 핵심 경로임을 뒷받침한다.
이러한 연구 결과는 Atg7 및 calpain 경로가 스트레스 상황에서 NSC의 생존 및 기능에 중요한 조절자로 작용한다는 점을 시사하며, 만성 스트레스로 인한 해마 기능 저하와 행동 장애를 완화할 수 있는 잠재적 치료 표적이 될 수 있음을 제시한다.
핵심어: 성체 해마 신경줄기세포, 만성 예측불가능 스트레스, 자가포식 세포사멸, calpain 2List of Contents
Abstract i
List of contents ii
List of tables iv
List of figures v
List of abbreviations vi
Ⅰ. Introduction 1
1.1 Adult neurogenesis 1
1.1.1 The discovery of adult neurogenesis 1
1.1.2 Mechanisms of neurogenesis 1
1.1.3 Regulation of adult neurogenesis 4
1.1.4 Adult neurogenesis and cognitive function 4
1.1.5 Adult neurogenesis and disease 4
1.2 Programmed cell death (PCD) 5
1.2.1 Apoptosis 6
1.2.2 Autophagic cell death (ACD) 9
1.2.3 Necroptosis 12
1.3 Stress 12
1.3.1 Type of stress 12
1.3.2 The physiology of stress 13
1.3.3 Stress and mental health disorder 15
1.3.4 Stress and immune function 15
1.3.5 Stress and metabolic disorders 15
ⅠⅠ. Chronic unpredictable stress induces autophagic cell death of adult hippocampal neural
stem cells 17
2.1 Introduction 17
2.2 Materials and Methods 19
2.2.1 Antibodies and reagents 19
2.2.2 Experimental animals 19
2.2.3 Chronic unpredictable stress (CUS) procedures 19
2.2.4 TAM injection· 21
2.2.5 Open field test 21
2.2.6 Y-maze test 21
2.2.7 Elevated plus maze test 21
2.2.8 Object location test 21
2.2.9 Constructs and stereotaxic injection 21
2.2.10 Immunohistochemistry 22
2.2.11 Stereology 22
2.2.12 Statistics 22
2.3 Results 23
2.3.1 Chronic unpredictable stress (CUS) induces behavioral changes in Ctrl mice 23
2.3.2 Atg7-NSC cKO mice are resistant to CUS-induced behavioral deficits 27
2.3.3 CUS induces death of adult hippocampal NSCs in Ctrl mice but not in Atg7-NSC
cKO mice 28
2.3.4 Autophagy flux is upregulated in Ctrl mice following CUS but not in Atg7-NSC
cKO mice 30
2.3.5 CUS does not activate apoptosis pathways in hippocampal NSCs 32
III. Calpain determines the tendency of adult hippocampal NSCs to ACD after
corticosterone treatment 35
3.1 Introduction 35
3.2 Materials and Methods 37
3.2.1 Antibodies and reagents 37
3.2.2 Cell culture 37
3.2.3 Cell death assay 37
3.2.4 Western blot 37
3.2.5 Quantitative real-time PCR (qRT-PCR) 38
3.2.6 Statistics 38
3.3 Results 40
3.3.1 Calpain 2 degradation in CORT-treated hippocampal NSCs is mediated by
ubiquitin-proteasome system (UPS) 40
3.3.2 Inhibition of calpain 2 accelerates ACD in CORT-treated hippocampal NSCs42
IV. Discussion 44
V. References 49
Abstract in KoreanDoctordCollectio
A polymer-based compliant force/torque and displacement sensor with creep compensation
No full textAutomation of assembly processes using robots remains challenging, requiring advanced capabilities in sensing for assembly state estimation and shock absorption to protect the robot from external forces. Traditional devices such as passive compliance devices and force/torque sensors provide only a subset of these functionalities. To integrate these capabilities into a single system, a polymer-based compliant force/torque and displacement sensor has been proposed. However, polymers classified as viscoelastic materials exhibit significant creep, degrading the sensing performance. Therefore, this paper addresses the development of a polymer-based compliance force/torque and displacement sensor with a creep compensation algorithm. The proposed sensor is made of viscoelastic materials to provide passive compliance, allowing it to adapt to external forces and protect the robot from shocks. Especially, it can achieve a remote center of compliance through a novel deformable structure. Moreover, it can measure the six-axis external forces and displacements generated by the passive compliance. In this process, the creep of the viscoelastic material is analyzed and compensated to improve the sensing performance. First, a stiffness analysis was conducted for the design of the sensor and finite element analysis was performed to verify that the sensor has a remote center of compliance. Then, a method for applying a creep compensation algorithm based on a viscoelastic model to the multi-axis force/torque and displacement sensor was proposed. The effectiveness of the creep compensation algorithm was evaluated through experiments, resulting in an 85.42 % reduction in creep error, a 63.52 % improvement in response time, and a 49.37 % reduction in hysteresis error. The proposed sensor can be utilized in various fields that require both flexibility and task state estimation such as robotic assembly, wearable robots, and medical robots. © 2025 Elsevier LtdFALSEsciescopu