Change In Average Intensity Research Articles

Dimensionality effects of g-C3N4 from wettability to solar light assisted self-cleaning and electrocatalytic oxygen evolution reaction

Unique interfacial properties of 2D materials make them more functional than their bulk counterparts in a catalytic application. In the present study, bulk and 2D graphitic carbon nitride nanosheet (bulk g-C3N4 and 2D-g-C3N4 NS) coated cotton fabrics and nickel foam electrode interfaces have been applied for solar light-driven self-cleaning of methyl orange (MO) dye and electrocatalytic oxygen evolution reaction (OER), respectively. Compared to bulk, 2D-g-C3N4 coated interfaces show higher surface roughness (1.094 > 0.803) and enhanced hydrophilicity (θ ∼ 32° < 62° for cotton fabric and θ ∼ 25° < 54° for Ni foam substrate) due to oxygen defect induction as confirmed from morphological (HR-TEM and AFM) and interfacial (XPS) characterizations. The self-remediation efficiencies for blank and bulk/2D-g-C3N4 coated cotton fabrics are estimated through colorimetric absorbance and average intensity changes. The self-cleaning efficiency for 2D-g-C3N4 NS coated cotton fabric is 87%, whereas the blank and bulk-coated fabric show 31% and 52% efficiency. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis determines the reaction intermediates for MO cleaning. 2D-g-C3N4 shows lower overpotential (108 mV) and onset potential (1.30 V) vs. RHE for 10 mA cm−2 OER current density in 0.1 M KOH. Also, the decreased charge transfer resistance (RCT = 12 Ω) and lower Tafel's slope (24 mV dec−1) of 2D-g-C3N4 make it the most efficient OER catalyst over bulk-g-C3N4 and state-of-the-art material RuO2. The pseudocapacitance behavior of OER governs the kinetics of electrode-electrolyte interaction through the electrical double layer (EDL) mechanism. The 2D electrocatalyst demonstrates long-term stability (retention ∼94%) and efficacy compared to commercial electrocatalysts.

Effect of quality of opto-mechanical components on fringes of diffraction Lloyd mirror interferometer

Diffraction Lloyd mirror interferometer (DLMI) is a relatively new interferometer where interference fringes are generated by superposition of two diffracted beams instead of two geometrical beams of light. The interferometer is suitable for performing basic investigations on diffraction and interference of light. In this work, a number of set-up parameters determining the performance of DLMI including characteristics of knife-edge, quality of mirror, quality of lenses, and effect of algorithm, are experimentally studied and reported for the first time. The effect of these parameters on interference fringes of DLMI is evaluated in terms of change in average intensity, signal to noise ratio (SNR) and contrast of the fringes. By optimizing above parameters, a DLMI set-up is realized and used for characterization of silicon optics fabricated using the single point diamond turning process. The validation results by a commercial optical profiler confirms the effectiveness of DLMI system. This study would provide useful reference for setting up the DLMI system for different applications such as optical profilometry, optical metrology, and to study the diffraction of light etc.

A Simple Method for Predicting Intensity Change Using the Peak Time Lag Between Lightning and Wind in Tropical Cyclones

AbstractUsing lightning data from the World‐Wide Lightning Location Network (WWLLN) and tracking data for Tropical Cyclones (TCs) from the China Meteorological Administration (CMA), the relationship between the peak time lag (Tlag) and the wind intensity change in severe and super typhoons was investigated. The Tlag between the maximum peaks of the inner‐core lightning and the TC intensity ranged from −132 to 198 h, while that of the entire TC lightning ranged from −174 to 198 h. The median Tlag values for strengthening and weakening storms were 54 and −21 h, respectively, while those for the entire TCs were 59 and −64 h, respectively. Lightning Frequency Peaks (LFPs) occurred more often with Average Intensity Changes (AICs) than intense intensity changes. Boundary equations were established based on the previous wind intensity change versus Tlag, and Tlag was simplified as a potential forecasting parameter of TC intensity change.

Deep learning-based attenuation correction in the absence of structural information for whole-body positron emission tomography imaging

Deriving accurate structural maps for attenuation correction (AC) of whole-body positron emission tomography (PET) remains challenging. Common problems include truncation, inter-scan motion, and erroneous transformation of structural voxel-intensities to PET µ-map values (e.g. modality artifacts, implanted devices, or contrast agents). This work presents a deep learning-based attenuation correction (DL-AC) method to generate attenuation corrected PET (AC PET) from non-attenuation corrected PET (NAC PET) images for whole-body PET imaging, without the use of structural information. 3D patch-based cycle-consistent generative adversarial networks (CycleGAN) is introduced to include NAC-PET-to-AC-PET mapping and inverse mapping from AC PET to NAC PET, which constrains NAC-PET-to-AC-PET mapping to be closer to one-to-one mapping. Since NAC PET images share similar anatomical structures to the AC PET image but lack contrast information, residual blocks, which aim to learn the differences between NAC PET and AC PET, are used to construct generators of CycleGAN. After training, patches from NAC PET images were fed into NAC-PET-to-AC-PET mapping to generate DL-AC PET patches. DL-AC PET image was then reconstructed through patch fusion. We conducted a retrospective study on 55 datasets of whole-body PET/CT scans to evaluate the proposed method. In comparing DL-AC PET with original AC PET, average mean error (ME) and normalized mean square error (NMSE) of the whole-body were 0.62% ± 1.26% and 0.72% ± 0.34%. The average intensity changes measured on sequential PET images with AC and DL-AC on both normal tissues and lesions differ less than 3%. There was no significant difference of the intensity changes between AC and DL-AC PET, which demonstrate DL-AC PET images generated by the proposed DL-AC method can reach a same level to that of original AC PET images. The method demonstrates excellent quantification accuracy and reliability and is applicable to PET data collected on a single PET scanner or hybrid platform with computed tomography (PET/CT) or magnetic resonance imaging (PET/MRI).

The Quantitative-Phase Dynamics of Apoptosis and Lytic Cell Death

Cell viability and cytotoxicity assays are highly important for drug screening and cytotoxicity tests of antineoplastic or other therapeutic drugs. Even though biochemical-based tests are very helpful to obtain preliminary preview, their results should be confirmed by methods based on direct cell death assessment. In this study, time-dependent changes in quantitative phase-based parameters during cell death were determined and methodology useable for rapid and label-free assessment of direct cell death was introduced. The goal of our study was distinction between apoptosis and primary lytic cell death based on morphologic features. We have distinguished the lytic and non-lytic type of cell death according to their end-point features (Dance of Death typical for apoptosis versus swelling and membrane rupture typical for all kinds of necrosis common for necroptosis, pyroptosis, ferroptosis and accidental cell death). Our method utilizes Quantitative Phase Imaging (QPI) which enables the time-lapse observation of subtle changes in cell mass distribution. According to our results, morphological and dynamical features extracted from QPI micrographs are suitable for cell death detection (76% accuracy in comparison with manual annotation). Furthermore, based on QPI data alone and machine learning, we were able to classify typical dynamical changes of cell morphology during both caspase 3,7-dependent and -independent cell death subroutines. The main parameters used for label-free detection of these cell death modalities were cell density (pg/pixel) and average intensity change of cell pixels further designated as Cell Dynamic Score (CDS). To the best of our knowledge, this is the first study introducing CDS and cell density as a parameter typical for individual cell death subroutines with prediction accuracy 75.4% for caspase 3,7-dependent and -independent cell death.

Early survival prediction in non-small cell lung cancer from PET/CT images using an intra-tumor partitioning method

PurposeTo explore prognostic and predictive values of a novel quantitative feature set describing intra-tumor heterogeneity in patients with lung cancer treated with concurrent and sequential chemoradiotherapy. MethodsLongitudinal PET-CT images of 30 patients with non-small cell lung cancer were analysed. To describe tumor cell heterogeneity, the tumors were partitioned into one to ten concentric regions depending on their sizes, and, for each region, the change in average intensity between the two scans was calculated for PET and CT images separately to form the proposed feature set. To validate the prognostic value of the proposed method, radiomics analysis was performed and a combination of the proposed novel feature set and the classic radiomic features was evaluated. A feature selection algorithm was utilized to identify the optimal features, and a linear support vector machine was trained for the task of overall survival prediction in terms of area under the receiver operating characteristic curve (AUROC). ResultsThe proposed novel feature set was found to be prognostic and even outperformed the radiomics approach with a significant difference (AUROCSALoP = 0.90 vs. AUROCradiomic = 0.71) when feature selection was not employed, whereas with feature selection, a combination of the novel feature set and radiomics led to the highest prognostic values. ConclusionA novel feature set designed for capturing intra-tumor heterogeneity was introduced. Judging by their prognostic power, the proposed features have a promising potential for early survival prediction.

Lies, Damn Lies, and Statistics: Why a Widely Used Sustainability Metric Fails and How to Improve It

Most of the world's major corporations now publicly report their sustainability performance for a number of key parameters, such as water use, greenhouse gas (GHG) emissions, and waste generated. The metrics most often used to track progress are “total inventory” (for example, the total liters of water used, or the total tons of GHGs emitted) and average intensity (total liters of water used per ton of product or per $1 million revenue). Because average intensity is normalized for the company's level of business activity, it is commonly presented and viewed as a measure of the company's actual year‐to‐year efficiency. But average intensity is often not a reliable measure of a company's true performance in sustainability.An improvement in efficiency requires a company to consume fewer resources or generate less waste in delivering a specified unit measure of goods or services. This article demonstrates that, although efficiency directly contributes to average intensity, the measure is influenced by a number of confounding factors that make the change in average intensity a potentially misleading indicator of improvements in efficiency. The authors present a more reliable measure of changes in efficiency—one that is likely to benefit corporate managements as well as users of sustainability data—that makes use of flexible budgeting techniques. Examples are provided that illustrate Bacardi Limited's application of the sustainability efficiency metric for external sustainability reporting.

Quantitative Analysis of Electron Beam Damage in Organic Thin Films.

In transmission electron microscopy (TEM) the interaction of an electron beam with polymers such as P3HT:PCBM photovoltaic nanocomposites results in electron beam damage, which is the most important factor limiting acquisition of structural or chemical data at high spatial resolution. Beam effects can vary depending on parameters such as electron dose rate, temperature during imaging, and the presence of water and oxygen in the sample. Furthermore, beam damage will occur at different length scales. To assess beam damage at the angstrom scale, we followed the intensity of P3HT and PCBM diffraction rings as a function of accumulated electron dose by acquiring dose series and varying the electron dose rate, sample preparation, and the temperature during acquisition. From this, we calculated a critical dose for diffraction experiments. In imaging mode, thin film deformation was assessed using the normalized cross-correlation coefficient, while mass loss was determined via changes in average intensity and standard deviation, also varying electron dose rate, sample preparation, and temperature during acquisition. The understanding of beam damage and the determination of critical electron doses provides a framework for future experiments to maximize the information content during the acquisition of images and diffraction patterns with (cryogenic) transmission electron microscopy.

Relationship between lightning activity and tropical cyclone intensity over the northwest Pacific

AbstractLightning data from the World Wide Lightning Location Network along with tropical cyclone (TC) track and intensity data from the China Meteorological Administration are used to study lightning activity in TCs over the northwest Pacific from 2005 to 2009 and to investigate the relationship between inner core lightning and TC intensity changes. Lightning in TCs over the northwest Pacific is more likely to occur in weak storms at tropical depression (10.8–17.1 m s−1) and tropical storm (17.2–24.4 m s−1) intensity levels, in agreement with past studies of Atlantic hurricanes. The greatest lightning density (LD) in the inner core appears in storms undergoing an intensity change of 15–25 m s−1 during the next 24 h. Lightning is observed in all storm intensity change categories: rapid intensification (RI), average intensity change (AIC), and rapid weakening (RW). The differences in LD between RI and RW are largest in the inner core, and the LD for RI cases is larger than for RW cases in the inner core (0–100 km). Lightning activity there, rather than in the outer rainbands, may be a better indicator for RI prediction in northwest Pacific storms. There was a marked increase in the lightning density of inner core during the RI stage for Super Typhoon Rammasun (2008). Satellite data for this storm show that the RI stage had the highest cloud top height and coldest cloud top temperatures, with all the minimum black body temperature values being below 200 K in the inner core.

Physical Activity and 5-Year Cognitive Decline in the Doetinchem Cohort Study

It is hypothesized that the intensity of physical activity habits, rather than the time spent on those activities, might mediate cognitive function. This study tested a possible association between changes in the time spent on or the average intensity of weekly physical activities and changes in cognitive function in healthy men and women. This longitudinal cohort study with 1,904 healthy men and women (45-75 years of age) assessed physical activity by a questionnaire and cognitive function with a neuropsychological test battery twice with an interval of 5 years. Multiple linear regression analyses showed that changes in the time spent on physical activities were not associated with changes in cognitive function over a 5-year period. By contrast, changes in average intensity of weekly activities were significantly and positively associated with processing speed (beta = 0.063; p < 0.05). In this longitudinal cohort study, an increase or smaller decline in average intensity was associated with a smaller age-related decline in processing speed, estimated at 6 years of aging.

The increasing intensity of the strongest tropical cyclones

Atlantic tropical cyclones are getting stronger on average, with a 30-year trend that has been related to an increase in ocean temperatures over the Atlantic Ocean and elsewhere. Over the rest of the tropics, however, possible trends in tropical cyclone intensity are less obvious, owing to the unreliability and incompleteness of the observational record and to a restricted focus, in previous trend analyses, on changes in average intensity. Here we overcome these two limitations by examining trends in the upper quantiles of per-cyclone maximum wind speeds (that is, the maximum intensities that cyclones achieve during their lifetimes), estimated from homogeneous data derived from an archive of satellite records. We find significant upward trends for wind speed quantiles above the 70th percentile, with trends as high as 0.3 +/- 0.09 m s(-1) yr(-1) (s.e.) for the strongest cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the very strongest tropical cyclones (99th percentile) over each ocean basin, with the largest increase at this quantile occurring over the North Atlantic, although not all basins show statistically significant increases. Our results are qualitatively consistent with the hypothesis that as the seas warm, the ocean has more energy to convert to tropical cyclone wind.

Silicon microelement vibration testing using conventional and heterodyned time-average interferometry with automated temporal and spatial phase stepping

This paper focuses on the applicability of the temporal (TPS) and spatial carrier (SCPS) phase-shifting techniques to the time-average interferogram intensity modulation distribution determination. Both techniques use the same mathematical formulae, but in different domains: temporal and spatial ones. They are sensitive to different types of errors. The influence of main experimental errors: phase-step miscalibration, spatial carrier miscalibration, average intensity changes and intensity noise in both the presented techniques on the fringe function determination (| J 0| or J 0 2 in case of sinusoidal vibrations), is discussed. The techniques are compared to find the most appropriate one. The time-average technique with heterodyning for small vibration–amplitude measurements is also discussed. The application of the SCPS method to this technique is shown for the first time.

Shedding Light on Biomolecule Conformational Dynamics Using Fluorescence Measurements of Trapped Ions

Biomolecule conformational change has been widely investigated in solution using several methods; however, much less experimental data about structural changes are available for completely isolated, gas-phase biomolecules. Studies of conformational change in unsolvated biomolecules are required to complement the interpretation of mass spectrometry measurements and in addition, can provide a means to directly test theoretical simulations of biomolecule structure and dynamics independent of a simulated solvent. In this Feature Article, we review our recent introduction of a fluorescence-based method for probing local conformational dynamics in unsolvated biomolecules through interactions of an attached dye with tryptophan (Trp) residues and fields originating on charge sites. Dye-derivatized biomolecule ions are formed by electrospray ionization and are trapped in a variable-temperature quadrupole ion trap in which they are irradiated with either continuous or short pulse lasers to excite fluorescence. Fluorescence is measured as a function of temperature for different charge states. Optical measurements of the dye fluorescence include average intensity changes, changes in the emission spectrum, and time-resolved measurements of the fluorescence decay. These measurements have been applied to the miniprotein, Trp-cage, polyproline peptides and to a beta-hairpin-forming peptide, and the results are presented as examples of the broad applicability and utility of these methods. Model fits to Trp-cage fluorescence data measured as a function of temperature provide quantitative information on the thermodynamics of conformational changes, which are reproduced well by molecular dynamics. Time-resolved measurements of the fluorescence decays of Trp-cage and small polyproline peptides definitively demonstrate the occurrence of fluorescence quenching by the amino acid Trp in unsolvated biomolecules.

Interferogram intensity modulation calculations using temporal phase shifting: error analysis

The phase shifting method is an effective tool to determine the intensity modulation distribution of a two-beam interferogram. We present numerical studies of the influence of two experimental errors on the results obtained using temporal phase stepping, i.e., the phase step miscalibration and average intensity changes between the component interferograms. Experimental studies of vibration mode patterns by time-average interferometry provide excellent verification of numerical findings. Comparative analysis of interferogram contrast and intensity modulation determination is included.

Radiometric calibration of vision cameras and intensity uncertainty estimation

The irradiance measurement performed by vision cameras is not noise-free due to both processing errors during CCD fabrication and the behaviour of the electronic device itself. A proper characterization of sensor performance, however, allows either removing the resulting noise from the image or accounting for it within image processing algorithms. This paper proposes a robust algorithm named R 2CIU for characterizing the noise sources affecting CCD performance with the aim of estimating the uncertainty of the intensity values yielded by vision cameras. R 2CIU makes use of sets of images of plane calibration cards such that, for every set, the average intensity changes. As it is shown in the paper, the (spatial) average and variance of (temporal) average images of every set lie in a parabola, while the (spatial) averages of the (temporal) average and variance images of every set lie in a straight line. R 2CIU exploits these two facts to compute the noise source distribution parameters by least-squares fitting. Intensity uncertainties are estimated next by a sum in quadrature of the variances of the different noise sources involved in the process of image formation. Experimental results and application examples can be found at the end of the paper.

Phase-shifting method contrast calculations in time-averaged interferometry: error analysis

Numerical simulations of the influence of the phase step miscalibration and average intensity changes between the registered frames on the time-averaged interferogram contrast calculated using the temporal phase-shifting (TPS) method are presented. The amplitude of sinusoidal vibration studied by the time-averaged method is encoded in the interferogram contrast or intensity modulation described by the zero-order Bessel function. The properties of the TPS method used for contrast determination are established. Experimental studies of vibration mode patterns of silicon microelements with specular reflection surfaces provide corroboration of theoretical and numerical findings.

Effects of signal envelope on the pitch of short sinusoidal tones.

The pitch of short sinusoidal tones with exponentially rising or decaying envelopes is judged higher than the pitch of a gated tone of the same frequency, duration, and energy. The upward pitch shift depends on the rise or decay rate, the intensity, and the frequency. The effect, which requires a nonlinearity in the auditory system, cannot be adequately explained by existing models of hearing. Control experiments on pitch matching for short tones of varying duration and varying intensity are described. These suggest that envelope-induced pitch effects are linked to changes in average intensity, so that they are essentially the same as intensity-induced pitch changes. A model based on these considerations is proposed.

The population dynamics and epidemiology of intestinal nematode infections

The paper reviews recent studies on the population biology, transmission dynamics and epidemiology of intestinal nematode infections. Particular attention is given to patterns of change in average intensity of infection with age, the possible role of acquired immunity assessed via reinfection studies after chemotherapy, evidence of predisposition to heavy (or light) infection by single and multiple species of parasites and control by mass, selective and targetted chemotherapy.

Turbulent scattering in an exponential atmosphere - A wave-optical solution

The thin-screen model for scattering of radiation by a turbulent atmosphere is generalized to the case where the mean phase change decreases exponentially as a function of distance across the screen. This is of interest because it models the effect of turbulent scattering in an isothermal average atmosphere. We present both the change in average intensity and average bending angle in terms of the r-m-s scattering angle introduced by the turbulence. We find, for example, that the effect of turbulent scattering on the mean scattering angle (and hence Doppler residuals) is approximately the same as that obtained from more heuristic calculations. The effect depends on wavelength only to the extent that the refractivity is a function of wavelength.