Design and development of highly sensitive PEDOT-PSS/AuNP hybrid nanocomposite-based sensor towards room temperature detection of greenhouse methane gas at ppb level

Herein, we present fabrication of a novel methane sensor based on poly (3,4-ethylenedioxythiophene:poly (styrene sulfonic acid)) (p-PEDOT-PSS) and gold nanoparticles (AuNPs) treated with dimethyl sulfoxide (DMSO) and Zonyl using a spin coating technique. The nanocomposite films were further post treated with H₂SO₄ to improve the charge transport mechanism. The structural and morphological features of the composites were analyzed through scanning electronic microscopy, transmission electron microscopy, Fourier transform infra-red spectroscopy, UV-Vis spectroscopy and thermogravimetric analysis. Treatment with organic solvents and post treatment of H₂SO₄ significantly enhances the conductivity of the composite to 1800 S cm⁻¹. The fabricated sensor shows an excellent sensing response, fast response and recovery time along with acceptable selectivity towards methane gas at ppb concentrations. Due to a simple fabrication technique, excellent conductivity, superior sensing performance and improved mechanical properties, the sensor fabricated in this study could potentially be used to detect greenhouse methane gas at low concentrations.

Fabrication of novel methane sensor based on PEDOT-PSS:AuNPs composite treated with DMSO and Zonyl using spin coating technique.     

新疆汉族与哈萨克族成人颜面比例分析与比较

目的:获得新疆地区的汉族和哈萨克族正常成年人的颜面比例特征及不同民族之间的差异。方法:从乌鲁木齐市在校大学生中,按标准随机选取汉族94名(男48,女46)和哈萨克族84名(男42,女42)正常成年人为研究对象,按照同一标准分别对每一位受试者拍摄正面像;将资料导入计算机,选择20个软组织标志点,并用photoshop测量软件对正面像进行15个项目的定点测量,建立了19项颜面比值,利用SPSS 19.0软件包对比值结果进行独立样本t检验。结果:性别差异:与女性相比,男性面部偏短宽,眼裂宽度较小,而鼻翼宽度较大;民族差异:不论男女,汉族人眼裂宽度、口裂宽度较小,而内眦及鼻翼宽度较大。结论:新疆地区的汉族与哈萨克族男女颜面比例存在一定差异。     

High performance flexible supercapacitors based on secondary doped PEDOT–PSS–graphene nanocomposite films for large area solid state devices

In this work, we propose the development of high performance and flexible supercapacitors using reduced graphene oxide (rGO) incorporated poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT–PSS) nanocomposites by secondary doping. The structural and morphological features of the composite film were analyzed in detail using SEM, AFM, FTIR, XPS and TGA. Secondary doping of ethylene glycol (EG) assisted by rGO incorporation significantly enhances the room temperature conductivity of PEDOT–PSS films from 3 S cm⁻¹ to nearly 1225 S cm⁻¹ for a 10 wt% composite. The secondary doped PEDOT–PSS:EG/rGO composite film demonstrated improved electrochemical performances with specific capacitance of 174 (F g⁻¹) and energy density of 810 (W h kg⁻¹) which is nearly 4 times greater than pristine PEDOT–PSS due to synergetic interactions between rGO and PEDOT–PSS. The prepared composite films show long term stability with capacitance retention of over 90% after 5000 cycles of charging–discharging. The nanocomposite films used in the present investigation demonstrates percolative behavior with a percolation threshold at 10 wt% of rGO in PEDOT–PSS. The assembled supercapacitor device could be bent and rolled-up without a decrease in electrochemical performance indicating the potential to be used in practical applications. To demonstrate the practical applicability, a rolled-up supercapacitor device was constructed that demonstrates operation of a red LED for 40 seconds when fully charged. This study will provide new dimensions towards designing cost effective, flexible and all solid-state supercapacitors with improved electrochemical performance using electrodes based on secondary doped PEDOT–PSS/rGO organic thin films.

In this work, we propose the development of high performance and flexible supercapacitors using reduced graphene oxide (rGO) incorporated poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT–PSS) nanocomposites by secondary doping.     

7‐Amino‐2‐aryl/hetero‐aryl‐5‐oxo‐5,8‐dihydro[1,2,4]triazolo[1,5‐a]pyridine‐6‐carbonitriles: Synthesis and adenosine receptor binding studies

A series of novel 7‐amino‐5‐oxo‐2‐substituted‐aryl/hetero‐aryl‐5,8‐dihydro[1,2,4]triazolo[1,5‐a]pyridine‐6‐carbonitriles ( 4a–4t ) was synthesized, characterized and evaluated for their binding affinity and selectivity towards hA₁, hA_2A, hA_2B and hA₃ adenosine receptors (ARs). Compound 4a with a phenyl ring at 2‐position of the triazolo moiety of the scaffold showed high affinity and selectivity for hA₁ AR (K_i hA₁ = 0.076 μM, hA_2A = 25.6 μM and hA₃ > 100 μM). Introduction of various electron donating and withdrawing groups at different positions of the phenyl ring resulted in drastic reduction in affinity and selectivity towards all the ARs, except compound 4b with a 4‐hydroxyphenyl group at 2‐position. Interestingly, the replacement of the phenyl ring with a smaller heterocyclic thiophene ring (π excessive system) resulted in further improvement of affinity for hA₁ AR of compound 4t (K_i hA₁ = 0.051 μM, hA_2A = 9.01 μM and hA₃ > 13.9 μM) while retaining the significant selectivity against all other AR subtypes similar to compound 4a . The encouraging results for compounds 4a and 4t indicate that substitution at 2‐position of the scaffold with π‐excessive systems other than thiophene may lead to even more potent and selective hA₁ AR antagonists.     

Highly sensitive ethylene glycol-doped PEDOT–PSS organic thin films for LPG sensing

In this study, for the first time we report the fabrication of low-cost ethylene glycol (EG)-doped PEDOT–PSS (poly 3,4-ethylenedioxythiophene:polystyrene sulfonate) organic thin film sensors for the detection of LPG at room temperature. The prepared thin films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis) spectroscopy and thermogravimetric analysis (TGA) techniques for the analysis of their structural and morphological features. The doping of EG strongly improved the conductivity of pure PEDOT–PSS films by three orders of magnitude. The gas sensing responses of pristine and doped PEDOT–PSS thin films were investigated at room temperature by fabricating a sensor device on an ITO-coated glass substrate. The gas sensing characteristics of the prepared thin films were investigated for liquified petroleum gas (LPG), dimethyl propane, methane and butane test gases. The EG-doped PEDOT–PSS thin films exhibited excellent sensitivity for all the test gases, especially towards LPG, at room temperature. The sensitivity of the doped PEDOT–PSS films was recorded to be >90% for LPG with improved response and recovery time. The stability study indicated that the sensing response of doped PEDOT–PSS thin films was highly stable over a period of 30 days. Due to enhanced sensitivity, stability and fast response and recovery times, these EG-doped PEDOT–PSS thin films can be used in gas sensor technology, especially towards the detection of LPG at room temperature.

In this study, for the first time we report the fabrication of low-cost ethylene glycol (EG)-doped PEDOT–PSS (poly 3,4-ethylenedioxythiophene:polystyrene sulfonate) organic thin film sensors for the detection of LPG at room temperature.     

新疆地区汉族与哈萨克族青年人侧貌特征分析比较

目的：分析新疆地区的汉族和哈萨克族正常成年人的侧貌特征及不同民族之间的差异。方法：从乌鲁木齐市在校大学生中，随机选取容貌端正的18～22岁汉族青年152名（男58，女94）和哈萨克族青年155名（男62，女93），按照同一标准分别对每一位受测者拍摄侧面像；将资料导入计算机，并用Photoshop 测量软件对侧面像进行多个测量项目的定点测量；利用SPSS 19．0软件对测量结果进行独立样本t检验。结果：性别差异：两民族男性双唇突度均大于女性，而女性鼻尖均较男性上翘，即更偏后上；民族差异：不论男女，汉族人双唇突度均大于哈萨克族，颏部相对不发达，鼻尖更加上翘。结论：新疆地区的汉族与哈萨克族男女侧貌均存在显著差异。     

Deoxyribonucleic Acid Barcoding of Some Indian Coelogyninae (Orchidaceae)

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Subtribe Coelogyninae (Epidendroideae, Orchidaceae) comprises of 16 genera. The present study is undertaken...     

新疆汉族与维吾尔族成人颜面比例分析

]目的：获得新疆地区汉族和维吾尔族正常成人颜面比例特征及不同民族之间的差异。方法从乌鲁木齐市在校大学生中,按一定标准随机选取一定数量的汉族和维吾尔族正常成人（男女分开）为研究对象,按照同一标准分别对每位受试者拍摄正面像;将资料导入计算机,选择20个软组织标志点,利用Photoshop软件对正面像进行15个项目的定点测量,建立19项颜面比值,利用SPSS19.0软件包对比值结果进行独立样本t检验。结果与女性相比,男性面部偏短宽,鼻翼宽度较大。不论男女,汉族人眼裂宽度、口裂宽度较小,而内眦及鼻翼宽度较大。结论新疆地区汉族与维吾尔族男女颜面比例存在一定差异。