The Ripple Effect of Graphite Nanofilm on Stretchable Polydimethylsiloxane for Optical Sensing

Graphene-based optical sensing devices have been widely studied for their broad band absorption, high carrier mobility, and mechanical flexibility. Due to graphene’s weak light absorption, studies on graphene-based optical sensing thus far have focused on hybrid heterostructure devices to enhance photo-absorption. Such hybrid devices need a complicated integration process and lead to deteriorating carrier mobility as a result of heterogeneous interfaces. Rippled or wrinkled graphene has been studied in electronic and optoelectronic devices. However, concrete demonstrations of the impact of the morphology of nanofilms (e.g., graphite and graphene) associated with light absorption in optical sensing devices have not been fully examined. This study explored the optical sensing potential of a graphite nanofilm surface with ripples induced by a stretchable polydimethylsiloxane (PDMS) supporting layer under different stretch:release ratios and then transferred onto silicon, both under experimental conditions and via simulation. The optical sensing potential of the rippled graphite nanofilm was significantly enhanced (260 mA/W at the stretch–release state of 30%), as compared to the pristine graphite/PDMS (20 mA/W at the stretch–release state of 0%) under laser illumination at a wavelength of 532 nm. In addition, the results of our simulated computation also confirmed the improved light absorption of rippled graphite nanofilm surface-based optical sensing devices, which was comparable with the results found in the experiment.

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Enhanced photodegradation of dimethoxybenzene isomers in/on ice compared to in aqueous solution

10.5194/acp-2021-875 ◽

2021 ◽

Author(s):

Ted Hullar ◽

Theo Tran ◽

Zekun Chen ◽

Fernanda Bononi ◽

Oliver Palmer ◽

...

Keyword(s):

Aqueous Solution ◽

Rate Constants ◽

Light Absorption ◽

Inorganic Compounds ◽

Photochemical Reactions ◽

Quantum Yields ◽

Experimental Conditions ◽

Substantial Impact ◽

Photodegradation Rate ◽

The Impact

Abstract. Photochemical reactions of contaminants in snow and ice can be important sources and sinks for various organic and inorganic compounds. Snow contaminants can be found in the bulk ice matrix, in internal liquid-like regions (LLRs), or in quasi-liquid layers (QLLs) at the air-ice interface, where they can readily exchange with the firn air. Some studies have reported that direct photochemical reactions occur faster in LLRs and QLLs than in aqueous solution, while others have found similar rates. Here, we measure the photodegradation rate constants of the three dimethoxybenzene isomers under varying experimental conditions, including in aqueous solution, in LLRs, and at the air-ice interface of nature-identical snow. Relative to aqueous solution, we find modest photodegradation enhancements (3- and 6-fold) in LLRs for two of the isomers, and larger enhancements (15- to 30-fold) at the air-ice interface for all three isomers. We use computational modeling to assess the impact of light absorbance changes on photodegradation rate enhancements at the interface. We find small (2–5 nm) bathochromic (red) absorbance shifts at the interface relative to in solution, which increases light absorption, but this factor only accounts for less than 50 % of the measured rate constant enhancements. The major factor responsible for photodegradation rate enhancements at the air-ice interface appears to be more efficient photodecay: estimated dimethoxybenzene quantum yields are 6- to 24-fold larger at the interface compared to in aqueous solution and account for the majority (51–96 %) of the observed enhancements. Using a hypothetical model compound with an assumed Gaussian-shaped absorbance peak, we find that a shift in the peak to higher or lower wavelengths can have a minor to substantial impact on photodecay rate constants, depending on the original location of the peak and the magnitude of the shift. Changes in other peak properties at the air-ice interface, such as peak width and height (i.e., molar absorptivity) can also impact rates of light absorption and direct photodecay.

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Glucuronides Hydrolysis by Intestinal Microbial β-Glucuronidases (GUS) Is Affected by Sampling, Enzyme Preparation, Buffer pH, and Species

Pharmaceutics ◽

10.3390/pharmaceutics13071043 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1043

Author(s):

Christabel Ebuzoeme ◽

Imoh Etim ◽

Autumn Ikimi ◽

Jamie Song ◽

Ting Du ◽

...

Keyword(s):

Enzyme Preparation ◽

Reaction System ◽

Reaction Rates ◽

Experimental Conditions ◽

Model Animal ◽

Fresh Feces ◽

Time Buffer ◽

Exogenous Compounds ◽

Activity Loss ◽

The Impact

Glucuronides hydrolysis by intestinal microbial β-Glucuronidases (GUS) is an important procedure for many endogenous and exogenous compounds. The purpose of this study is to determine the impact of experimental conditions on glucuronide hydrolysis by intestinal microbial GUS. Standard probe 4-Nitrophenyl β-D-glucopyranoside (pNPG) and a natural glucuronide wogonoside were used as the model compounds. Feces collection time, buffer conditions, interindividual, and species variations were evaluated by incubating the substrates with enzymes. The relative reaction activity of pNPG, reaction rates, and reaction kinetics for wogonoside were calculated. Fresh feces showed the highest hydrolysis activities. Sonication increased total protein yield during enzyme preparation. The pH of the reaction system increased the activity in 0.69–1.32-fold, 2.9–12.9-fold, and 0.28–1.56-fold for mouse, rat, and human at three different concentrations of wogonoside, respectively. The Vmax for wogonoside hydrolysis was 2.37 ± 0.06, 4.48 ± 0.11, and 5.17 ± 0.16 μmol/min/mg and Km was 6.51 ± 0.71, 3.04 ± 0.34, and 0.34 ± 0.047 μM for mouse, rat, and human, respectively. The inter-individual difference was significant (4–6-fold) using inbred rats as the model animal. Fresh feces should be used to avoid activity loss and sonication should be utilized in enzyme preparation to increase hydrolysis activity. The buffer pH should be appropriate according to the species. Inter-individual and species variations were significant.

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WON-OCDMA System Based on MW-ZCC Codes for Applications in Optical Wireless Sensor Networks

Sensors ◽

10.3390/s21020539 ◽

2021 ◽

Vol 21 (2) ◽

pp. 539

Author(s):

Saleh Seyedzadeh ◽

Andrew Agapiou ◽

Majid Moghaddasi ◽

Milan Dado ◽

Ivan Glesk

Keyword(s):

Optical Networks ◽

Video Surveillance ◽

Multiple Access ◽

Optical Sensing ◽

Multiple Access Interference ◽

Service Differentiation ◽

Sensor Data ◽

Variable Weight ◽

Code Division Multiple ◽

The Impact

The growing demand for extensive and reliable structural health monitoring resulted in the development of advanced optical sensing systems (OSS) that in conjunction with wireless optical networks (WON) are capable of extending the reach of optical sensing to places where fibre provision is not feasible. To support this effort, the paper proposes a new type of a variable weight code called multiweight zero cross-correlation (MW-ZCC) code for its application in wireless optical networks based optical code division multiple access (WON-OCDMA). The code provides improved quality of service (QoS) and better support for simultaneous transmission of video surveillance, comms and sensor data by reducing the impact of multiple access interference (MAI). The MW-ZCC code’s power of two code-weight properties provide enhanced support for the needed service differentiation provisioning. The performance of this novel code has been studied by simulations. This investigation revealed that for a minimum allowable bit error rate of 10−3, 10−9 and 10−12 when supporting triple-play services (sensing, datacomms and video surveillance, respectively), the proposed WON-OCDMA using MW-ZCC codes could support up to 32 simultaneous services over transmission distances up to 32 km in the presence of moderate atmospheric turbulence.

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Investigation of the Impact of Hot-Carrier-Induced Interface State Generation on Carrier Mobility in nMOSFET

IEEE Transactions on Electron Devices ◽

10.1109/ted.2021.3080657 ◽

2021 ◽

pp. 1-8

Author(s):

Zhicheng Wu ◽

Jacopo Franco ◽

Brecht Truijen ◽

Philippe Roussel ◽

Ben Kaczer ◽

...

Keyword(s):

Carrier Mobility ◽

Interface State ◽

Hot Carrier ◽

State Generation ◽

The Impact

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Searching for energy-resolved quasi-periodic oscillations in AGN

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa4024 ◽

2021 ◽

Author(s):

Dominic I Ashton ◽

Matthew J Middleton

Keyword(s):

Power Law ◽

Spectral Component ◽

Broad Band ◽

Initial Study ◽

Periodic Oscillations ◽

Single Observation ◽

Curved Space ◽

Multiple Observations ◽

Band Noise ◽

The Impact

Abstract X-ray quasi-periodic oscillations (QPOs) in AGN allow us to probe and understand the nature of accretion in highly curved space-time, yet the most robust form of detection (i.e. repeat detections over multiple observations) has been limited to a single source to-date, with only tentative claims of single observation detections in several others. The association of those established AGN QPOs with a specific spectral component has motivated us to search the XMM-Newton archive and analyse the energy-resolved lightcurves of 38 bright AGN. We apply a conservative false alarm testing routine folding in the uncertainty and covariance of the underlying broad-band noise. We also explore the impact of red-noise leak and the assumption of various different forms (power-law, broken power-law and lorentzians) for the underlying broad-band noise. In this initial study, we report QPO candidates in 6 AGN (7 including one tentative detection in MRK 766) from our sample of 38, which tend to be found at characteristic energies and, in four cases, at the same frequency across at least two observations, indicating they are highly unlikely to be spurious in nature.

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Device Modeling and Design of Inverted Solar Cell Based on Comparative Experimental Analysis between Effect of Organic and Inorganic Hole Transport Layer on Morphology and Photo-Physical Property of Perovskite Thin Film

Materials ◽

10.3390/ma14092191 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2191

Author(s):

Xiaolan Wang ◽

Xiaoping Zou ◽

Jialin Zhu ◽

Chunqian Zhang ◽

Jin Cheng ◽

...

Keyword(s):

Light Absorption ◽

Short Circuit ◽

Perovskite Solar Cells ◽

Open Circuit ◽

Hole Transport ◽

Transport Layer ◽

Hole Transport Layer ◽

Functional Layer ◽

Perovskite Layer ◽

The Impact

It is crucial to find a good material as a hole transport layer (HTL) to improve the performance of perovskite solar cells (PSCs), devices with an inverted structure. Polyethylene dioxythiophene-poly (styrene sulfonate) (PEDOT:PSS) and inorganic nickel oxide (NiOx) have become hotspots in the study of hole transport materials in PSCs on account of their excellent properties. In our research, NiOx and PEDOT: PSS, two kinds of hole transport materials, were prepared and compared to study the impact of the bottom layer on the light absorption and morphology of perovskite layer. By the way, some experimental parameters are simulated by wx Analysis of Microelectronic and Photonic Structures (wxAMPS). In addition, thin interfacial layers with deep capture levels and high capture cross sections were inserted to simulate the degradation of the interface between light absorption layer and PEDOT:PSS. This work realizes the combination of experiment and simulation. Exploring the mechanism of the influence of functional layer parameters plays a vital part in the performance of devices by establishing the system design. It can be found that the perovskite film growing on NiOx has a stronger light absorption capacity, which makes the best open-circuit voltage of 0.98 V, short-circuit current density of 24.55 mA/cm2, and power conversion efficiency of 20.01%.

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A flexible ChIP-sequencing simulation toolkit

BMC Bioinformatics ◽

10.1186/s12859-021-04097-5 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

An Zheng ◽

Michael Lamkin ◽

Yutong Qiu ◽

Kevin Ren ◽

Alon Goren ◽

...

Keyword(s):

Ground Truth ◽

Peak Calling ◽

Simulation Framework ◽

Experimental Conditions ◽

Ground Truth Data ◽

Chip Sequencing ◽

Genome Wide ◽

Experimental Parameters ◽

Differential Binding ◽

The Impact

Abstract Background A major challenge in evaluating quantitative ChIP-seq analyses, such as peak calling and differential binding, is a lack of reliable ground truth data. Accurate simulation of ChIP-seq data can mitigate this challenge, but existing frameworks are either too cumbersome to apply genome-wide or unable to model a number of important experimental conditions in ChIP-seq. Results We present ChIPs, a toolkit for rapidly simulating ChIP-seq data using statistical models of key experimental steps. We demonstrate how ChIPs can be used for a range of applications, including benchmarking analysis tools and evaluating the impact of various experimental parameters. ChIPs is implemented as a standalone command-line program written in C++ and is available from https://github.com/gymreklab/chips. Conclusions ChIPs is an efficient ChIP-seq simulation framework that generates realistic datasets over a flexible range of experimental conditions. It can serve as an important component in various ChIP-seq analyses where ground truth data are needed.

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