39 research outputs found

    Enhanced Capacitive Humidity Sensing Performance at Room Temperature via Hydrogen Bonding of Cyanopyridone-Based Oligothiophene Donor

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    Cyanopyridone-based oligothiophene donors with both hydrophobic and hydrophilic characters have been evaluated as active layers within simple capacitive devices for humidity sensing at room temperature. Surface studies using atomic force microscopy revealed a self-assembled nanofibrous network with a thin needle-like structure for the terminal hydroxy example (CP6), devoid in the methyl example (CP1). The sensing performance of each sensor was investigated over a broad range of relative humidity levels as a function of capacitance at room temperature. The sensor CP6 demonstrated favourable features such as high sensitivity (12.2 pF/%RH), quick response/recovery (13 s/20.7 s), wide working range of relative humidity (10%–95% RH), low hysteresis (0.57%), outstanding recyclability, and excellent long-term stability. From the results obtained, hydrophilicity and hydrogen bonding appear to play a vital role in enhancing humidity sensing performance, leading to possible new design directions for simple organic semiconductor-based sensors.</jats:p

    Evaluate Database Management System Quality By Analytic Hierarchy Process (AHP) and Simple Additive Weighting (SAW) Methodolog

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    Any organization that intends to use component-based software development, like outsourcing software, must first evaluate existing components against system requirements to find the best fit among many alternatives. As a result, there should be a mechanism to help with decision-making. Our proposed methodology tries to select the best alternative among available components, using the best decision-making approach. As an integrated method for order preference, the methodology in this paper uses two well-known criterion decision-making procedures, namely Analytic Hierarchy Process (AHP) and Simple Additive Weighting (SAW). By analyzing and selecting the optimal solution among a variety of Out Sourcing (OS) modules, the new model design makes the decision-making process easier. We evaluated two software attributes and predicted which was more effective. In this case, the advantage of utilizing AHP is that it allows the developer to evaluate the structure of the OS selection problem and calculate weights for the chosen criteria. After that, the SAW technique is used to calculate the alternatives ratings for OS components. The integration strategy used in our model and the resulting preference indication, which is produced as an explicit numeric value

    Distinguishing Type 2 Diabetes from Type 1 Diabetes in African American and Hispanic American Pediatric Patients

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    To test the hypothesis that clinical observations made at patient presentation can distinguish type 2 diabetes (T2D) from type 1 diabetes (T1D) in pediatric patients aged 2 to 18.Medical records of 227 African American and 112 Hispanic American pediatric patients diagnosed as T1D or T2D were examined to compare parameters in the two diseases. Age at presentation, BMI z-score, and gender were the variables used in logistic regression analysis to create models for T2D prediction.The regression-based model created from African American data had a sensitivity of 92% and a specificity of 89%; testing of a replication cohort showed 91% sensitivity and 93% specificity. A model based on the Hispanic American data showed 92% sensitivity and 90% specificity. Similarities between African American and Hispanic American patients include: (1) age at onset for both T1D and T2D decreased from the 1980s to the 2000s; (2) risk of T2D increased markedly with obesity. Racial/ethnic-specific observations included: (1) in African American patients, the proportion of females was significantly higher than that of males for T2D compared to T1D (p<0.0001); (2) in Hispanic Americans, the level of glycated hemoglobin (HbA1c) was significantly higher in T1D than in T2D (p<0.002) at presentation; (3) the strongest contributor to T2D risk was female gender in African Americans, while the strongest contributor to T2D risk was BMI z-score in Hispanic Americans.Distinction of T2D from T1D at patient presentation was possible with good sensitivity and specificity using only three easily-assessed variables: age, gender, and BMI z-score. In African American pediatric diabetes patients, gender was the strongest predictor of T2D, while in Hispanic patients, BMI z-score was the strongest predictor. This suggests that race/ethnic specific models may be useful to optimize distinction of T1D from T2D at presentation

    The HIV-1 Nef protein binds argonaute-2 and functions as a viral suppressor of RNA interference

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    The HIV-1 accessory protein Nef is an important virulence factor. It associates with cellular membranes and modulates the endocytic machinery and signaling pathways. Nef also increases the proliferation of multivesicular bodies (MVBs), which are sites for virus assembly and budding in macrophages. The RNA interference (RNAi) pathway proteins Ago2 and GW182 localize to MVBs, suggesting these to be sites for assembly and turnover of the miRNA-induced silencing complex (miRISC). While RNAi affects HIV replication, it is not clear if the virus encodes a suppressor activity to overcome this innate host response. Here we show that Nef colocalizes with MVBs and binds Ago2 through two highly conserved Glycine-Tryptophan (GW) motifs, mutations in which abolish Nef binding to Ago2 and reduce virus yield and infectivity. Nef also inhibits the slicing activity of Ago2 and disturbs the sorting of GW182 into exosomes resulting in the suppression of miRNA-induced silencing. Thus, besides its other activities, the HIV-1 Nef protein is also proposed to function as a viral suppressor of RNAi (VSR)

    Naphthalene diimide-based electron transport materials for perovskite solar cells

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    The development of perovskite solar cells (PSCs) as an efficient and cost-effective alternative to traditional approaches to solar energy transduction has received much recent attention, and there has been considerable progress made with reported power conversion efficiencies now surpassing 25%. This development is encouraging and is a result of intensive research on device design, factors affecting long-term stability of PSCs, and systematic material development in which electron transport layer (ETL) materials play a crucial role to afford high-performance PSC devices. ETL materials, including (6-(1,10-phenanthrolin-3-yl)naphthalen-2-yl)diphenylphosphine oxide (Phen-NaDPO), and n-type materials based on the naphthalene diimide (NDI) structure, appear to be amongst the most promising materials to date. This article provides an up-to-date review on organic n-type ETL materials, both polymeric and small molecules, based on NDI format, detailing reports of structures with key relevant parameters, such as the efficiency and stability of PSCs. The review is written from a perspective of organic chemistry and we believe this will provide fundamental advice on the future design of new ETL materials based on NDIs that will afford more efficient and stable PSCs

    Functionalization of spiro[fluorene-9,9′-xanthene] with diketopyrrolopyrrole to generate a promising, three-dimensional non-fullerene acceptor

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    A spiro[fluorene-9,9′-xanthene], often described as a "low-cost spiro,"has been functionalized with terminal diketopyrrolopyrrole units to generate a promising, three-dimensional non-fullerene acceptor. The new acceptor, coded as SFX1, was readily synthesized using the Suzuki cross-coupling reaction and was sufficiently soluble in a variety of commonly used, film-processing solvents such as chlorobenzene and o-dichlorobenzene. SFX1 displayed promising optoelectronic properties and the HOMO/LUMO energy levels complementary to the commercially available and commonly used donor polymers P3HT and PTB7. The joining of two high-potential building blocks-the spiro[fluorene-9,9′-xanthene] and diketopyrrolopyrrole-demonstrates a new strategy where the device performance [D : A 1 : 1.2 = 9.42% (D = PTB7)] validates its use as a potential, three-dimensional non-fullerene acceptor

    Enhanced Photovoltaic Efficiency via Control of Self-Assembly in Cyanopyridone-Based Oligothiophene Donors.

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    The optoelectronic properties of functional π-conjugated organic materials are affected by their ability to self-assemble within thin films of devices. There are limited reports that demonstrate the positive impact of self-assembly on the photovoltaic performance of organic solar cells. Here, we demonstrate that hydrogen-bonded supramolecular arrays of a cyanopyridone-based oligothiophene donor, CP6, show notable improvement in photovoltaic performance upon self-assembly into a nanofibrous network. The honeycomb-like blend network exhibited higher hole mobility, leading to efficient charge generation and transport. The photovoltaic performance of CP6 was superior to that of two structural analogues, CP5 and CP1, and was attributed to the enhanced capability of CP6 to self-assemble into a film morphology favorable for BHJ devices. The BHJ devices comprising CP6 and the conventional fullerene acceptor (PC71BM) exhibited an efficiency of 7.26%, which is greater than that of CP5 (5.19%) and CP1 (3.11%) and is among the best-performing, cyanopyridone-based oligothiophene donors described to date
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