Visible light assisted NO₂ sensing at room temperature by CdS nanoflake array

Li, Hua-Yao,Yoon, Ji-Won,Lee, Chul-Soon,Lim, Kyeorei,Yoon, Ji-Wook,Lee, Jong-Heun Elsevier 2018 Sensors and actuators. B, Chemical Vol.255 No.3

<P><B>Abstract</B></P> <P>A Highly ordered CdS nanoflake array was fabricated by CVD, and its gas sensing characteristics were investigated. The sensor exhibited high response (resistance ratio) of 89% to 5 part per million (ppm) nitrogen dioxide (NO<SUB>2</SUB>) under green LED illumination (wavelength 500–540nm, irradiance 21W/m<SUP>2</SUP>) with excellent selectivity and little interference by humidity. Moreover, the sensor showed promising potential for operating under fluorescent lamp and natural solar light, which can be used for medical diagnosis and indoor/outdoor environment monitoring. This performance is attributed to the low band gap energy (2.4eV) of CdS and the unique morphology of nanoflake array which can enhance both the light absorption and conductivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CdS NO<SUB>2</SUB> gas sensor operated under both fluorescent lamp and natural solar light. </LI> <LI> 2D nanoflake array CdS films for enhanced light absorption and charge transport. </LI> <LI> CdS gas sensor with high response to NO<SUB>2</SUB>, little influence by humidity. </LI> <LI> Elucidation of visible-light-enhanced NO<SUB>2</SUB> sensing mechanism. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cordycepin protects against β-amyloid and ibotenic acid-induced hippocampal CA1 pyramidal neuronal hyperactivity

Yao, Li-Hua,Wang, Jinxiu,Liu, Chao,Wei, Shanshan,Li, Guoyin,Wang, Songhua,Meng, Wei,Liu, Zhi-Bin,Huang, Li-Ping The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.6

Cordycepin exerts neuroprotective effects against excitotoxic neuronal death. However, its direct electrophysiological evidence in Alzheimer's disease (AD) remains unclear. This study aimed to explore the electrophysiological mechanisms underlying the protective effect of cordycepin against the excitotoxic neuronal insult in AD using whole-cell patch clamp techniques. ${\beta}$-Amyloid ($A{\beta}$) and ibotenic acid (IBO)-induced injury model in cultured hippocampal neurons was used for the purpose. The results revealed that cordycepin significantly delayed $A{\beta}$ + IBO-induced excessive neuronal membrane depolarization. It increased the onset time/latency, extended the duration, and reduced the slope in both slow and rapid depolarization. Additionally, cordycepin reversed the neuronal hyperactivity in $A{\beta}$ + IBO-induced evoked action potential (AP) firing, including increase in repetitive firing frequency, shortening of evoked AP latency, decrease in the amplitude of fast afterhyperpolarization, and increase in membrane depolarization. Further, the suppressive effect of cordycepin against $A{\beta}$ + IBO-induced excessive neuronal membrane depolarization and neuronal hyperactivity was blocked by DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine $A_1$ receptor-specific blocker). Collectively, these results revealed the suppressive effect of cordycepin against the $A{\beta}$ + IBO-induced excitotoxic neuronal insult by attenuating excessive neuronal activity and membrane depolarization, and the mechanism through the activation of $A_1R$ is strongly recommended, thus highlighting the therapeutic potential of cordycepin in AD.

Cordycepin protects against β–amyloid and ibotenic acid– induced hippocampal CA1 pyramidal neuronal hyperactivity

Li-Hua Yao,Jinxiu Wang,Chao Liu,Shanshan Wei,Guoyin Li,Songhua Wang,Wei Meng,Zhi-Bin Liu,Li-Ping Huang 대한약리학회 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.6

Cordycepin exerts neuroprotective effects against excitotoxic neuronal death. However, its direct electrophysiological evidence in Alzheimer’s disease (AD) remains unclear. This study aimed to explore the electrophysiological mechanisms underlying the protective effect of cordycepin against the excitotoxic neuronal insult in AD using whole-cell patch clamp techniques. β-Amyloid (Aβ) and ibotenic acid (IBO)–induced injury model in cultured hippocampal neurons was used for the purpose. The results revealed that cordycepin significantly delayed Aβ + IBO–induced excessive neuronal membrane depolarization. It increased the onset time/latency, extended the duration, and reduced the slope in both slow and rapid depolarization. Additionally, cordycepin reversed the neuronal hyperactivity in Aβ + IBO–induced evoked action potential (AP) firing, including increase in repetitive firing frequency, shortening of evoked AP latency, decrease in the amplitude of fast afterhyperpolarization, and increase in membrane depolarization. Further, the suppressive effect of cordycepin against Aβ + IBO–induced excessive neuronal membrane depolarization and neuronal hyperactivity was blocked by DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A1 receptor–specific blocker). Collectively, these results revealed the suppressive effect of cordycepin against the Aβ + IBO–induced excitotoxic neuronal insult by attenuating excessive neuronal activity and membrane depolarization, and the mechanism through the activation of A1R is strongly recommended, thus highlighting the therapeutic potential of cordycepin in AD.

Cordycepin protects against β–amyloid and ibotenic acid– induced hippocampal CA1 pyramidal neuronal hyperactivity

Li-Hua Yao,Jinxiu Wang,Chao Liu,Shanshan Wei,Guoyin Li,Songhua Wang,Wei Meng,Zhi-Bin Liu,Li-Ping Huang 대한약리학회 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.6

Cordycepin exerts neuroprotective effects against excitotoxic neuronal death. However, its direct electrophysiological evidence in Alzheimer’s disease (AD) remains unclear. This study aimed to explore the electrophysiological mechanisms underlying the protective effect of cordycepin against the excitotoxic neuronal insult in AD using whole-cell patch clamp techniques. β-Amyloid (Aβ) and ibotenic acid (IBO)–induced injury model in cultured hippocampal neurons was used for the purpose. The results revealed that cordycepin significantly delayed Aβ + IBO–induced excessive neuronal membrane depolarization. It increased the onset time/latency, extended the duration, and reduced the slope in both slow and rapid depolarization. Additionally, cordycepin reversed the neuronal hyperactivity in Aβ + IBO–induced evoked action potential (AP) firing, including increase in repetitive firing frequency, shortening of evoked AP latency, decrease in the amplitude of fast afterhyperpolarization, and increase in membrane depolarization. Further, the suppressive effect of cordycepin against Aβ + IBO–induced excessive neuronal membrane depolarization and neuronal hyperactivity was blocked by DPCPX (8-cyclopentyl-1,3-dipropylxanthine, an adenosine A1 receptor–specific blocker). Collectively, these results revealed the suppressive effect of cordycepin against the Aβ + IBO–induced excitotoxic neuronal insult by attenuating excessive neuronal activity and membrane depolarization, and the mechanism through the activation of A1R is strongly recommended, thus highlighting the therapeutic potential of cordycepin in AD.

Role of Stromal Cell-Derived Factor-1 in Endothelial Progenitor Cell-Mediated Vascular Repair and Regeneration

Li Ji-Hua,Li Yang,Huang Dan,Yao Min 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.5

Endothelial progenitor cells (EPCs) are immature endothelial cells that participate in vascular repair and postnatal neovascularization and provide a novel and promising therapy for the treatment of vascular disease. Studies in different animal models have shown that EPC mobilization through pharmacological agents and autologous EPC transplantation contribute to restoring blood supply and tissue regeneration after ischemic injury. However, these effects of the progenitor cells in clinical studies exhibit mixed results. The therapeutic efficacy of EPCs is closely associated with the number of the progenitor cells recruited into ischemic regions and their functional abilities and survival in injury tissues. In this review, we discussed the regulating role of stromal cell-derived factor-1 (also known CXCL12, SDF-1) in EPC mobilization, recruitment, homing, vascular repair and neovascularization, and analyzed the underlying machemisms of these functions. Application of SDF-1 to improve the regenerative function of EPCs following vascular injury was also discussed. SDF-1 plays a crucial role in mobilizing EPC from bone marrow into peripheral circulation, recruiting the progenitor cells to target tissue and protecting against cell death under pathological conditions; thus improve EPC regenerative capacity. SDF-1 are crucial for regulating EPC regenerative function, and provide a potential target for improve therapeutic efficacy of the progenitor cells in treatment of vascular disease.

Flexible Room-Temperature NH₃ Sensor for Ultrasensitive, Selective, and Humidity-Independent Gas Detection

Li, Hua-Yao,Lee, Chul-Soon,Kim, Do Hong,Lee, Jong-Heun American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.33

<P>Ammonia (NH<SUB>3</SUB>) is an irritant gas with a unique pungent odor; sub-parts per million-level breath ammonia is a medical biomarker for kidney disorders and <I>Helicobacter pylori</I> bacteria-induced stomach infections. The humidity varies in both ambient environment and exhaled breath, and thus humidity dependence of gas-sensing characteristics is a great obstacle for real-time applications. Herein, flexible, humidity-independent, and room-temperature ammonia sensors are fabricated by the thermal evaporation of CuBr on a polyimide substrate and subsequent coating of a nanoscale moisture-blocking CeO<SUB>2</SUB> overlayer by electron-beam evaporation. CuBr sensors coated with a 100 nm-thick CeO<SUB>2</SUB> overlayer exhibits an ultrahigh response (resistance ratio) of 68 toward 5 ppm ammonia with excellent gas selectivity, rapid response, reversibility, and humidity-independent sensing characteristics at room temperature. In addition, the sensing performance remains stable after repetitive bending and long-term operation. Moreover, the sensors exhibit significant response to the simulated exhaled breath of patients with <I>H. pylori</I> infection; the simulated breath contains 50 ppb NH<SUB>3</SUB>. The sensors thus show promising potential in detecting sub-parts per million-level NH<SUB>3</SUB>, regardless of humidity fluctuations, which can open up new applications in wearable devices for in situ medical diagnosis and indoor/outdoor environment monitoring.</P> [FIG OMISSION]</BR>

Doping effect on the adsorption of Na atom onto graphenes

Li-Hua Yao,Wen-Qiang Cao,Mao-Sheng Cao 한국물리학회 2016 Current Applied Physics Vol.16 No.5

We investigate the adsorption of Na atoms on pristine graphene and four types of defect graphenes using the first-principles calculations. The adsorption energies, electronic structures, Na storage capacities and the average potentials of Na atoms on different graphenes are calculated. The adsorption energies of Na atoms on B-doped, vacancy and B-doped vacancy graphenes are 1.93 eV, 2.46 eV, and 2.08 eV, respectively, which are much lower than that of Na on the pristine graphene (0.71 eV) and Na on Ndoped graphene (0.27 eV). The orbital hybridizations in the B-doped, vacancy and B-doped vacancy graphenes can be observed from the partial density of states, while there is no obvious orbital hybridization in the N-doped graphene as well as the pristine graphene. The B-doped vacancy graphene has the best Na storage capacity, while B-doped and vacancy graphenes also possess better Na storage capacities than those of the pristine graphene and N-doped graphene. This work demonstrates that the graphene introducing both B dopant and vacancy is expected to be a potential material for storing Na.

Rapid Detection and Monitoring Therapeutic Efficacy of Mycobacterium tuberculosis Complex Using a Novel Real-Time Assay

( Jiang Li Juan ),( Wen Juan Wu ),( Hai Wu ),( Son Sik Ryang ),( Jian Zhou ),( Wei Wu ),( Tao Li ),( Jian Guo ),( Hong Hai Wang ),( Shui Hua Lu ),( Yao Li ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.9

We combined real-time RT-PCR and real-time PCR (R/P) assays using a hydrolysis probe to detect Mycobacterium tuberculosis complex (MTBC)-specific 16S rRNA and its rRNA gene (rDNA). The assay was applied to 28 nonrespiratory and 207 respiratory specimens from 218 patients. Total nucleic acids (including RNA and DNA) were extracted from samples, and results were considered positive if the repeat RT-PCR threshold cycle was ≤35 and the ratio of real-time RT-PCR and real-time PCR load was ≥1.51. The results were compared with those from existing methods, including smear, culture, and real-time PCR. Following resolution of the discrepant results between R/P assay and culture, the overall sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) of all samples (including nonrespiratory and respiratory specimens) were 98.2%, 97.2%, 91.7%, and 99.4%, respectively, for R/P assay, and 83.9%, 89.9%, 72.3%, and 94.7%, respectively, for real-time PCR. Furthermore, the R/P assay of four patient samples showed a higher ratio before treatment than after several days of treatment. We conclude that the R/P assay is a rapid and accurate method for direct detection of MTBC, which can distinguish viable and nonviable MTBC, and thus may guide patient therapy and public health decisions.

Discriminative detection of indoor volatile organic compounds using a sensor array based on pure and Fe-doped In₂O₃ nanofibers

Lee, Chul-Soon,Li, Hua-Yao,Kim, Bo-Young,Jo, Young-Moo,Byun, Hyung-Gi,Hwang, In-Sung,Abdel-Hady, Faissal,Wazzan, Abdulaziz A.,Lee, Jong-Heun Elsevier 2019 Sensors and actuators. B Chemical Vol.285 No.-

<P><B>Abstract</B></P> <P>Representative indoor volatile organic compounds (VOCs) such as benzene, xylene, toluene, formaldehyde, and ethanol need to be detected in a highly sensitive and discriminative manner because of their different impact on human health. In this study, pure and 0.05, 0.1, 0.3, and 0.5 at% Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofibers were prepared by electrospinning and their gas sensing characteristics toward the aforementioned VOCs were investigated. The doping of In<SUB>2</SUB>O<SUB>3</SUB> nanofiber sensor with 0.05 and 0.1 at% Fe shifted the temperature to show the maximum responses to benzene, xylene, and toluene, and reduced responses to ethanol and formaldehyde, thus demonstrating changed gas selectivity. The gas sensing characteristics of 0.5 at% Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofiber sensor were substantially different from those of the other sensors. Significantly different gas sensing patterns of pure and Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> sensors could be used to discriminate between the five different VOCs at 375 °C and to distinguish between the aromatic and non-aromatic gases at all sensing temperatures. The mechanism underlying the Fe-induced change in gas sensing characteristics has been discussed in relation to the variation of catalytic activity, morphology, oxygen adsorption, and charge carrier concentration.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fabrication of a sensor array using pure and Fe-doped In<SUB>2</SUB>O<SUB>3</SUB> nanofibers. </LI> <LI> Discriminative detection of benzene, xylene, toluene, ethanol, and formaldehyde. </LI> <LI> Distinction between aromatic and non-aromatic indoor pollutants using sensor array. </LI> <LI> Gas sensing mechanism underlying Fe-induced change in response and selectivity. </LI> </UL> </P>

Highly discriminative and sensitive detection of volatile organic compounds for monitoring indoor air quality using pure and Au-loaded 2D In₂O₃ inverse opal thin films

Lee, Chul-Soon,Dai, Zhengfei,Kim, Do Hong,Li, Hua-Yao,Jo, Young-Moo,Kim, Bo-Young,Byun, Hyung-Gi,Hwang, Insung,Lee, Jong-Heun Elsevier 2018 Sensors and actuators. B Chemical Vol.273 No.-

<P><B>Abstract</B></P> <P>The lack of gas selectivity in oxide semiconductor chemiresistors has long been an obstacle to realizing discriminative detection of indoor volatile organic compounds (VOCs) with different health impacts. A simple and reliable algorithm to discriminate between critically harmful aromatic VOCs (benzene, xylene, and toluene) and less harmful ethanol is suggested by the simple combination of sensor signals from pure In<SUB>2</SUB>O<SUB>3</SUB> and Au-loaded In<SUB>2</SUB>O<SUB>3</SUB> 2D inverse opal (IO) thin films prepared by heat-treating the precursor-dipped self-assembled polystyrene templates and Au deposition. The Au-loaded In<SUB>2</SUB>O<SUB>3</SUB> IO sensor showed unprecedentedly high responses to 5 ppm ethanol (resistance ratio = 1640.2) and comparably high responses to 5 ppm benzene, <I>p-</I>xylene, and toluene (resistance ratio range of 674.5–1012.9). Such high gas responses were attributed to the periodically porous and thus highly gas-accessible structures, while the clear discrimination between aromatic VOCs and ethanol was achieved by tuning gas selectivity through systematic control of the size, morphology, and loading concentration of Au nano-catalysts. The results of this study can be used for reliable and precise monitoring of indoor air pollutants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Discriminative detection of indoor pollutant gases using Au-In<SUB>2</SUB>O<SUB>3</SUB> 2D Inverse Opals. </LI> <LI> Selective and sensitive detection of ethanol using In<SUB>2</SUB>O<SUB>3</SUB> 2D Inverse Opals. </LI> <LI> Ultrahigh response (resistance ratio = ∼1000) of Au-In<SUB>2</SUB>O<SUB>3</SUB> sensor to 5 ppm <I>p</I>-xylene. </LI> <LI> A simple and reliable algorithm for gas selectivity using two-sensor array. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>