Cumulative Amplification Research Articles

Quantitative tracing of typical herbicides and their metabolites in sorghum agrosystems for fate tendency and cumulative risk

Elucidating the combined exposure of agrochemicals is essential for safeguarding human health and agroecosystem safety. A rapid and high-sensitivity UHPLC-MS/MS method was developed for simultaneous quantification of nine compounds in sorghum by an assembly-line optimization process with a limit of quantitation of 0.001 mg/kg. The concentration variation of atrazine, quinclorac, fluroxypyr-meptyl and metabolites was reflected by terminal magnitudes of ≤0.0665 mg/kg. Additionally, atrazine was dealkylated to deethyl atrazine and desethyl desisopropyl atrazine at concentrations of 0.0014–0.0058 mg/kg during the sorghum harvest. Acceptable health hazardous of atrazine and quinclorac for all life cycle populations were comparatively assessed via deterministic and probabilistic models, in which atrazine gained an 83.55 % share of cumulative dietary risks. Rural residents had significantly higher risks than urban residents, and children were the most sensitive group. Despite the low health risks, combined exposure to herbicides and their metabolites should be continuously stressed, given their cumulative amplification effects.

Polarization regulation in core-shell HNTs@Metal/C for high-performance of electromagnetic wave absorption

Enhancing polarization loss is an effective method to improve electromagnetic wave absorption (EMA) performance. However, constructing more interfaces and inducing defects is a significant challenge in polarization regulation. This paper reports synthesizing a core-shell structure HNTs@M/C (M=Cu, Co, Zn) by pyrolysis of metal-organic frameworks (MOFs). The enhancement of conduction loss is attributed to the electronic conduction network formed by the carbon layer and the metal particles. Co nanoparticles (NPs) create more interfaces with the carbon layer, significantly boosting polarization performance. Additionally, Zn sublimation induces numerous defects in the carbon layer, leading to cumulative amplification of polarization and stronger dielectric resonances in HNTs@Zn/C. With a thickness of 2.4 mm, the HNTs@Zn/C achieve an effective absorption bandwidth (EAB) of 6.9 GHz, covering the entire Ku-band with a minimum reflection loss of −61 dB. This work provides design strategies for interfacial and point interaction of polarization regulation.

Assumption-free analysis for amplification-based quantitative nucleic acid detection.

The accurate detection and quantification of biological species that are rarely present but potentially devastating is of paramount importance for the life sciences, biosecurity, food safety, and environmental monitoring. Consequently, there has been significant interest in the sensitive and accurate detection of nucleic acids, leveraging both chemical and biological methods. Among these, quantitative polymerase chain reaction (qPCR) is regarded as the gold standard due to its sensitivity and precision in identifying specific nucleic acid targets. Despite the widespread adoption of qPCR for nucleic acid detection, the analysis of qPCR data typically depends on the use of calibrated standard curves and a threshold method to interpret signal measurements. In this study, we use a stochastic simulation to show the limitations of the threshold method due to its assumptions on amplification kinetics. We propose a new approach for the absolute quantification of nucleic acids that overcomes these limitations by reconstructing the efficiency profile across amplification cycles and using cumulative amplification folds to build a standard curve, thus avoiding the constant efficiency assumption. Our method, validated through experiments with nucleic acid amplification in the presence of potent inhibitors, demonstrates improved accuracy in quantifying nucleic acids, avoiding the systematic errors of the threshold method. This innovation enhances the reliability of nucleic acid quantification, especially where traditional methods struggle with kinetic variability.

Ozone–gravity wave interaction in the upper stratosphere/lower mesosphere

Abstract. The increase in amplitudes of upward propagating gravity waves (GWs) with height due to decreasing density is usually described by exponential growth. Recent measurements show some evidence that the upper stratospheric/lower mesospheric gravity wave potential energy density (GWPED) increases more strongly during the daytime than during the nighttime. This paper suggests that ozone–gravity wave interaction can principally produce such a phenomenon. The coupling between ozone-photochemistry and temperature is particularly strong in the upper stratosphere where the time–mean ozone mixing ratio decreases with height. Therefore, an initial ascent (or descent) of an air parcel must lead to an increase (or decrease) in ozone and in the heating rate compared to the environment, and, hence, to an amplification of the initial wave perturbation. Standard solutions of upward propagating GWs with linear ozone–temperature coupling are formulated, suggesting amplitude amplifications at a specific level during daytime of 5 % to 15 % for low-frequency GWs (periods ≥4 h), as a function of the intrinsic frequency which decreases if ozone–temperature coupling is included. Subsequently, the cumulative amplification during the upward level-by-level propagation leads to much stronger GW amplitudes at upper mesospheric altitudes, i.e., for single low-frequency GWs, up to a factor of 1.5 to 3 in the temperature perturbations and 3 to 9 in the GWPED increasing from summer low to polar latitudes. Consequently, the mean GWPED of a representative range of mesoscale GWs (horizontal wavelengths between 200 and 1100 km, vertical wavelengths between 3 and 9 km) is stronger by a factor of 1.7 to 3.4 (2 to 50 J kg−1, or 2 % to 50 % in relation to the observed order of 100 J kg−1, assuming initial GW perturbations of 1 to 2 K in the middle stratosphere). Conclusively, the identified process might be an important component in the middle atmospheric circulation, which has not been considered up to now.

Urban flood forecasting based on the coupling of numerical weather model and stormwater model: A case study of Zhengzhou city

Study regionUrban built-up area of Zhengzhou, China. Study focusA coupled urban flood forecasting model based on WRF-SWMM is proposed. Different spatial resolution data as input for WRF (Weather Research and Forecasting Model) to study the characteristics of forecasting precipitation, combined with measured precipitation series, the SWMM (Storm Water Management Model) was driven to forecast the urban flood process. New hydrological insights for the study regionUsing the WRF-SWMM coupling model to simulate flood disasters can effectively improve the timeliness of urban flood prediction. The results indicate that a spatial resolution of 0.25-degree improved the overall precipitation prediction results. With an increase in lead time, the prediction performance of the WRF decreased. The WRF model can simulate results effectively owing to its sensitivity to bimodal rainfall patterns. When the WRF model produces an overestimate (or underestimate), part of the urban canals in the SWMM model will also carry out a high forecast (or low forecast) output of flood peak discharge. The SWMM model also has a cumulative amplification effect on the results of flood simulation. In addition, the quantitative accuracy of precipitation forecasts plays a vital role in urban flood simulation, and the existing coupling models based on WRF-SWMM can generate reasonable forecasts 3–6 h in advance.

Repeated noninvasive stimulation of the ventromedial prefrontal cortex reveals cumulative amplification of pleasant compared to unpleasant scene processing: A single subject pilot study.

The ventromedial prefrontal cortex (vmPFC) is a major hub of the reward system and has been shown to activate specifically in response to pleasant / rewarding stimuli. Previous studies demonstrate enhanced pleasant cue reactivity after single applications of transcranial direct current stimulation (tDCS) to the vmPFC. Here we present a pilot case study in which we assess the cumulative impact of multiple consecutive vmPFC-tDCS sessions on the processing of visual emotional stimuli in an event-related MEG recording design. The results point to stable modulation of increased positivity biases (pleasant > unpleasant stimulus signal strength) after excitatory vmPFC stimulation and a reversed pattern (pleasant < unpleasant) after inhibitory stimulation across five consecutive tDCS sessions. Moreover, cumulative effects of these emotional bias modulations were observable for several source-localized spatio-temporal clusters, suggesting an increase in modulatory efficiency by repeated tDCS sessions. This pilot study provides evidence for improvements in the effectiveness and utility of a novel tDCS paradigm in the context of emotional processing.

High Accuracy Profile Measurement With a New Virtual Multi-Probe Scanning System

We present a novel virtual multi-probe scanning system and a new error separation method for the exact optical profile reconstruction. The system realized the multi-probe function by a single probe that fixed on a flexible hinge stage. The flexible hinge stage has a millimeter-level travel range and driven by a voice coil motor to realize the function of the multi-probe. In this work, a high accuracy profile measurement with a high lateral resolution is realized under the errors of the straightness, zero-adjustment, and yaw. The new method can obtain multiple sets of straightness error of the guideway in one scanning measurement. This novel virtual multi-probe scanning system and its corresponding method has the following benefits: (i) using a single probe to separate straightness error without reversal, and can accurately reconstruct the profile, (ii) the reconstructed profile has a very high lateral resolution, depending on the lateral resolution (μm level) of the probe, (iii) the cumulative amplification effect of zero-adjustment error can be eliminated by our method, (iv) the new method can obtain multiple sets of straightness error with higher reliability and accuracy compared with only one set. These benefits are proved by theoretical derivation and simulation. Experiments also prove that the new method can reconstruct the profile with high accuracy and lateral resolution.

FUNCTIONS AND MODES OFINFORMATION DEVELOPMENT OF ECONOMY: METHODS AND MODELS

Informatization intensification of the modern economy stresses the importance to discuss the following group of issues: 1) the establishment of criteria and measurement of the effectiveness of the information system; 2) the definition of the information potential of the agent and the assessment of effective information action; 3) information security of the social and economic system. The purpose of the study is to analyze theoretically the functions of various types of information with the determination of the efficiency of information and the modes of economic systems information development. Economic agents are known to search for relevant information that is only a part of total information in the system to make efficient decisions. The action of an agent as well as the development of an economic system is generally characterised with an efficiency coefficient that assesses the opportunity to obtain relevant information. The research methodology is the classification method that allows us to highlight the properties of information, to introduce quantitative indicators for measuring these properties and using mathematical tools to determine possible relationships between them, building theoretical models of the dynamics of information development of economy. Using this approach the functions of information, namely, notification, accumulation, cumulative amplification within the framework of consideration of the informational interaction schemes “object-agent” and “agent-agent” have been determined. The criterion of information potential of the controlled system and the information efficiency coefficient have been introduced. The latter means the ratio of information security to the level of information completeness of the system. Using the analysis of the dynamics of the efficiency and the ratio of relevant and general information, the modes of information development of the controlled system have been determined; three options for the accumulation of information with the ability to quantify the effect that determines the development of the knowledge economy have been suggested. Standard, enhanced and storage accumulations have been shown in the framework of the “object-agent” information interaction model, formal parameters for their quantitative assessment have been introduced. We have proved that one of the goals of economic policy should be the insurance of the necessary regime of information development of the economy, that is aimed at solving problems in the field of information security due to the fact that the functions of information can be violated, i. e. performed with different results, which indicates the dysfunction of the information system and economic management. Such the approach will reduce the depth of dysfunctions of economic policy measures and the application of the information security loop proposed by the author will provide the tool for comparing the damage and benefits from possible information threats, which predetermines the practical application of the conducted theoretical analysis applied to different information modes. Sustainable development of the modern economy should consider the elimination of information threats especially in the context of overcoming opportunism in the form of deliberate distortions of information in order to obtain additional benefits. At the same time, the use of the information security loop for the development of economic policy measures will allow not only to diagnose the damage and benefits within the existing information processing regime, but also to identify the dynamics of the economic system development as a result of changes in the ratio of information benefits and costs. Keywords information, informatization of economy, information potential of economy, function of information, information development mode, information interaction models, information security of economy, combinatory principle, information security loop, dysfunction of information system, dysfunction of economic policy.

Comparative analysis of the EGFR, HER2, c-MYC, and MET variations in colorectal cancer determined by three different measures: gene copy number gain, amplification status and the 2013 ASCO/CAP guideline criterion for HER2 testing of breast cancer

BackgroundThe purpose of this study was to explore gene copy number (GCN) variation of EGFR, HER2, c-MYC, and MET in patients with primary colorectal cancer (CRC).MethodsDual-colour silver-enhanced in situ hybridization was performed in tissue samples of 334 primary CRC patients. The amplification status (GCN ratio ≥2) and GCN gain (average GCN ≥4) data for the EGFR, HER2, c-MYC and MET genes were obtained. GCN variation was also assessed by the criterion of the 2013 ASCO/CAP guidelines for HER2 testing.ResultsAmplification of EGFR, HER2, c-MYC and MET was detected in 8 (2.4%), 20 (6.0%), 29 (8.7%), and 14 (4.2%) patients, respectively. Of 66 patients with at least one amplified gene, five exhibited co-amplification of genes studied (HER2-MET co-amplification: two patients; HER2-c-MYC co-amplification: two patients; EGFR-c-MYC co-amplification: one patient). There were 109 patients with GCN gains of one or more genes (EGFR: 11/334, HER2: 29/334, c-MYC; 60/334, MET: 48/334) and 32.1% (35/109) had multiple GCN gains. When each GCN was assessed by the criterion of the ASCO/CAP 2013 guideline for HER2 testing, 116 people showed positive or equivocal results for one or more genes. The cumulative amplification status had no association with patients’ outcome. However, the cumulative results of the GCN gain and GCN status determined according to the ASCO/CAP guideline had a significant prognostic correlation in the univariate analysis (P values of 0.006 and 0.022, respectively). In the multivariate analysis, GCN gain and GCN status were independent prognostic factors (P values of 0.010 and 0.017, respectively).ConclusionsIn this study, we evaluated GCN variation of four genes in a large sample of Korean CRC patients. The amplification status was not related to patient outcome. However, the GCN gain and GCN status according to the ASCO/CAP 2013 guideline were independent prognostic factors.

Selective Amplification of the Primary Exciton in a MoS_{2} Monolayer.

Optoelectronics applications for transition-metal dichalcogenides are still limited by weak light absorption and their complex exciton modes are easily perturbed by varying excitation conditions because they are inherent in atomically thin layers. Here, we propose a method of selectively amplifying the primary exciton (A^{0}) among the exciton complexes in monolayer MoS_{2} via cyclic reexcitation of cavity-free exciton-coupled plasmon propagation. This was implemented by partially overlapping a Ag nanowire on a MoS_{2} monolayer separated by a thin SiO_{2} spacer. Exciton-coupled plasmons in the nanowire enhance the A^{0} radiation in MoS_{2}. The cumulative amplification of emission enhancement by cyclic plasmon traveling reaches approximately twentyfold selectively for the A^{0}, while excluding other B exciton and multiexciton by significantly reduced band filling, without oscillatory spectra implying plasmonic cavity effects.

Finite amplitude folding: transition from exponential to layer length controlled growth

A new finite amplitude theory of folding has been developed by the combined application of analytical, asymptotic and numerical methods. The existing linear folding theory has been improved by considering nonlinear weakening of membrane stresses, which is caused by the stretching of the competent layer during folding. The resulting theory is simple and accurate for finite amplitude folding and is not restricted to infinitesimal amplitudes, as is the classical linear theory of folding. Two folding modes relevant to most natural settings were considered: (i) both membrane and fiber stresses are viscous during folding (the ‘viscous’ mode); (ii) membrane stresses are viscous whereas fiber stresses are elastic (the ‘viscoelastic’ mode). For these two modes, the new theory provided a nonlinear, ordinary differential equation for fold amplification during shortening and an estimate for crossover amplitude and strain where the linear theory breaks down. A new analytical relationship for amplitude versus strain was derived for strains much larger than the crossover strain. The new relationship agrees well with complete 2D numerical solutions for up to threefold shortening, whereas the exponential solution predicted by the linear theory is inaccurate by orders of magnitude for strains larger than the crossover value. Analysis of the crossover strain and amplitude as a function of the controlling parameters demonstrates that the linear theory is only applicable for a small range of amplitudes and strains. This renders unreliable the large strain prediction of wavelength selection based on the linear theory, especially for folding at high competence contrasts. To resolve this problem, the new finite amplitude theory is used to calculate the evolution of the growth rate spectra during progressive folding. The growth rate spectra exhibited splitting of a single maximum (predicted by the linear theory) into two maxima at large strains. This bifurcation occurred for both deformation modes. In contrast, the spectra of the cumulative amplification ratio (current over initial amplitude) maintained a single maximum value throughout. The wavelength selectivity is found to decrease at large strains, which helps explain the aperiodic forms of folds commonly observed in nature and the absence of long dominant wavelengths for high competence contrast folding. Calculation of the cumulative amplification spectra for different initial amplitude distributions, ranging from white to red noise, showed that the initial noise has a strong influence on the amplitude spectra for small strains. For larger strains, however, the cumulative amplification spectra were similar despite the strong difference in the initial noise.

Finite amplitude folding: transition from exponential to layer length controlled growth

Abstract A new finite amplitude theory of folding has been developed by the combined application of analytical, asymptotic and numerical methods. The existing linear folding theory has been improved by considering nonlinear weakening of membrane stresses, which is caused by the stretching of the competent layer during folding. The resulting theory is simple and accurate for finite amplitude folding and is not restricted to infinitesimal amplitudes, as is the classical linear theory of folding. Two folding modes relevant to most natural settings were considered: (i) both membrane and fiber stresses are viscous during folding (the ‘viscous’ mode); (ii) membrane stresses are viscous whereas fiber stresses are elastic (the ‘viscoelastic’ mode). For these two modes, the new theory provided a nonlinear, ordinary differential equation for fold amplification during shortening and an estimate for crossover amplitude and strain where the linear theory breaks down. A new analytical relationship for amplitude versus strain was derived for strains much larger than the crossover strain. The new relationship agrees well with complete 2D numerical solutions for up to threefold shortening, whereas the exponential solution predicted by the linear theory is inaccurate by orders of magnitude for strains larger than the crossover value. Analysis of the crossover strain and amplitude as a function of the controlling parameters demonstrates that the linear theory is only applicable for a small range of amplitudes and strains. This renders unreliable the large strain prediction of wavelength selection based on the linear theory, especially for folding at high competence contrasts. To resolve this problem, the new finite amplitude theory is used to calculate the evolution of the growth rate spectra during progressive folding. The growth rate spectra exhibited splitting of a single maximum (predicted by the linear theory) into two maxima at large strains. This bifurcation occurred for both deformation modes. In contrast, the spectra of the cumulative amplification ratio (current over initial amplitude) maintained a single maximum value throughout. The wavelength selectivity is found to decrease at large strains, which helps explain the aperiodic forms of folds commonly observed in nature and the absence of long dominant wavelengths for high competence contrast folding. Calculation of the cumulative amplification spectra for different initial amplitude distributions, ranging from white to red noise, showed that the initial noise has a strong influence on the amplitude spectra for small strains. For larger strains, however, the cumulative amplification spectra were similar despite the strong difference in the initial noise.

Universal dissymmetry and the origin of biomolecular chirality

Handed systems are distributed over four general domains. These span the fundamental particles, the molecular enantiomers, the crystal enantiomorphs, and the spiral galaxies. The characterisation of the molecular enantiomers followed from the identification of the crystal enantiomorphs and revealed a chiral homogeneity in the biomolecules of the organic world. The origin of the homogeneity has been variously ascribed to a universal dissymmetric force, from Pasteur, or to a chance choice of the initial enantiomer perpetuated by the stereoselection of diastereomer production with recycling, from Fischer's “key and lock” hypothesis. The classical chiral fields identified by Curie require a particular time or location on the Earth's surface for a determinate molecular enantioselection, as do the weak charged current agencies of the non-classical weak interaction. The weak neutral current of the electroweak interaction provides a constant and uniform chiral agency which favours both the l-series of amino acids and polypeptides and the parent aldotriose of the d-series of sugars. The enantiomeric bias of the electroweak interaction is small at the molecular level: it may become significant either as a trigger-perturbation guiding the transition from a metastable autocatalytic racemic process to one of the two constituent enantiomeric reaction channels, or by cumulative amplification in a large chirally-homogeneous aggregate of enantiomer units.

Substrate-leash amplification with ribonuclease S-peptide and S-protein.

The S-peptide and S-protein fragments of ribonuclease S (RNase S, no EC no. assigned) have been immobilized onto separate Sepharose gels via a "leash" of polycytidylic acid substrate. Each of these gels releases its RNase fragment when treated with the complementary enzyme fragment or with RNase A (EC 3.1.27.5), and the released fragments recombine to give RNase S activity. Thus this system provides substrate-leash amplification (SLA), such that more enzymatic activity is eluted from the system than is applied. For example, 100 pg of RNase applied to the S-peptide gel is amplified by 1.9 X 10(4) to the equivalent of 1.9 micrograms of activity in 20 h, when followed by combination of the released S-peptide with excess S-protein. We also tested a three-stage amplification system, with a pair of S-peptide and S-protein gels at each stage. In this system the cumulative amplification of the initial 1-ng dose of RNase A is 4.9, 52, and 25-fold after each stage, respectively. Only 2 mg of each SLA gel is used per stage in these experiments, reflecting the magnitude of their production of RNase S activity.