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Assessment of mercury(II) bioavailability using a bioluminescent bacterial biosensor: Practical and theoretical challenges

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Journal of Environmental Sciences 2010年第8期22卷 1137-1143页

作者： Paulo R G Barrocas William m Landing robert J m Hudson Department of Sanitation and Environmental Health National School of Public Health Oswaldo Cruz Foundation Department of Oceanography Florida State University. Tallahassee Department of Natural Resources and Environmental Sciences University of Illinois

Critical methodological challenges in the microbial biosensor approach to assessing Hg（II） bioavailability were evaluated from the perspective of analytical chemists. The main challenge stems from the fact that the chemical speciation of Hg（II） in natural waters exerts a major control on its bioavailability, yet its natural complexation equilibria are extensively altered during conventional bioassays. New data, obtained using a bioluminescent Hg（II）-biosensor, that illustrate these challenges are presented and potential solutions proposed.

关键词： mercury bioavailability biosensor chemical speciation bioluminescent

Comparison of three-dimensional fluorescence analysis methods for predicting formation of trihalomethanes and haloacetic acids

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Journal of Environmental Sciences 2015年第1期27卷 159-167页

作者： Nicolás m.Peleato robert C.Andrews Department of Civil Engineering University of Toronto

This work investigated the application of several fluorescence excitation–emission matrix analysis methods as natural organic matter（NOm） indicators for use in predicting the formation of trihalomethanes（THms） and haloacetic acids（HAAs）. Waters from four different sources（two rivers and two lakes） were subjected to jar testing followed by 24 hr disinfection by-product formation tests using chlorine. NOm was quantified using three common measures： dissolved organic carbon, ultraviolet absorbance at 254 nm, and specific ultraviolet absorbance as well as by principal component analysis, peak picking,and parallel factor analysis of fluorescence spectra. Based on multi-linear modeling of THms and HAAs, principle component（PC） scores resulted in the lowest mean squared prediction error of cross-folded test sets（THms： 43.7（μg/L）^2, HAAs： 233.3（μg/L）^2）. Inclusion of principle components representative of protein-like material significantly decreased prediction error for both THms and HAAs. Parallel factor analysis did not identify a protein-like component and resulted in prediction errors similar to traditional NOm surrogates as well as fluorescence peak picking. These results support the value of fluorescence excitation–emission matrix–principal component analysis as a suitable NOm indicator in predicting the formation of THms and HAAs for the water sources studied.

关键词： Natural organic matter Fluorescence Principal component analysis PARAFAC Disinfection byproducts Drinking water

An explainable AI framework for robust and transparent data-driven wind turbine power curve models

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Energy and AI 2024年第1期15卷 312-327页

作者： Simon Letzgus Klaus-robert müller machine Learning Group Technische Universitβe BerlinStraβe des 17.Juni 135Berlin10623Germany Berlin Institute for the Foundations of Learning and Data Berlin10587Germany Department of Artificial Intelligence Korea UniversitySeoul136-713South Korea max Planck Institute for Informatics Saarbrücken66123Germany

In recent years,increasingly complex machine learning methods have become state-of-the-art in modelling wind turbine power curves based on operational *** these methods often exhibit superior performance on test sets,they face criticism due to a perceived lack of transparency and concerns about their robustness in dynamic,non-stationary environments encountered by wind *** this work,we address these issues and present a framework that leverages explainable artificial intelligence methods to gain systematic insights into data-driven power curve *** its core,we propose a metric to quantify how well a learned model strategy aligns with the underlying physical principles of the *** novel tool enables model validation beyond the conventional error metrics in an automated *** demonstrate,for instance,its capacity as an indicator for model generalization even when limited data is ***,it facilitates understanding how decisions made during the machine learning development process,such as data selection,pre-processing,or training parameters,affect learned *** a result,we obtain physically more reasonable models,a prerequisite not only for robustness but also for meaningful insights into turbine operation by domain *** latter,we illustrate in the context of wind turbine performance *** summary,the framework aims to guide researchers and practitioners alike toward a more informed selection and utilization of data-driven wind turbine power curve models.

关键词： Explainable AI(XAI) machine learning Wind energy Wind turbine power curve SCADA Condition monitoring

modern imaging techniques for preoperative detection of distant metastases in gastric cancer

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World Journal of Gastroenterology 2015年第37期21卷 10502-10509页

作者： robert m Kwee Thomas C Kwee Department of Radiology Maastricht University Medical Center Department of Radiology University Medical Center Utrecht

A substantial portion of patients with newly diagnosed gastric cancer has distant metastases(m1 disease).These patients have a very poor prognosis and it is generally accepted that they should be treated with noncurative intent. Because it dramatically changes prognosis and treatment plans, it is very important to diagnose distant metastases. In this article, the definition, pathways, incidence and sites of distant metastases in gastric cancer are ***, the current performance of imaging in detecting distant metastases in newly diagnosed gastric cancer is outlined and future prospects are discussed.

关键词： Gastric cancer Ultrasonography Distant metastases

Specifications of Targeting Heterochromatin modifications in Plants

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molecular Plant 2018年第3期11卷 381-387页

作者： Jered m. Wendte robert J. Schmitz Department of Genetics University of Georgia Athens GA 30602 USA

Plants encode a diverse repertoire of DNA methyltransferases that have specialized to target cytosines for methylation in specific sequence contexts. These include the de novo methyltransferase, DOmAINS REARRANGED mETHYLTRANSFERASE 2 （DRm2）, which methylates cytosines in all sequence contexts through an RNA-guided process, the CHROmOmETHYLASES （CmTs）, which methylate CHH and CHG cytosines （where H is A, T, or C）, and mETHYLTRANSFERASE 1 （mET1）, which maintains methylation of symmetrical CG contexts. In this review, we discuss the sequence specificities and targeting of each of these pathways. In particular, we highlight recent studies that indicate CmTs preferentially target CWG or CWA/CAW motifs （where W is A or T）, and discuss how self-reinforcing feedback loops between DNA methyltransferases and histone modifications characteristic of heterochromatin specify targeting. Finally, the initiating events that lead to gene body methylation are discussed as a model illustrating how interde- pendent targeting of different silencing pathways can potentiate the establishment of off-target epialleles.

关键词： heterochromatin DNA methylation gene body methylation epiallele DNA methyltransferase,chromomethylase

Identification of isopeptidase activity in the midgut of insects： Purification, properties and nutritional ecology of a Hofmannophila pseudospretella （Lepidoptera： Oecophoridae） larval enzyme

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Insect Science 2010年第4期17卷 325-334页

作者： robert m. Simpson John T. Christeller Plant and Food Research Institute Tennant Drive Palmerston North 4474 Private Bag 11 030 New Zealand

A γ-glutamyl transpeptidase （isopeptidase） has been purified 580-fold to homogeneity from the midgut of keratinophagous larvae of Hofmannophila pseudospretella. The enzyme is a single polypeptide of molecular mass 80 kDa. The enzyme was identified by its hydrolytic activity against the synthetic substrate, γ-glutamyl-AmC, its molecular mass and inhibition profile compared to other γ-glutamyl transpeptidases. The enzyme is low or absent from most other insect digestive systems apart from other keratinophagous lepidopteran larvae and predatory carabids. While isopepfide bonds are present in high levels of the proteins in the diet of keratinophages, their presence in the diet of predatory beetles has not been established.

关键词： γ-glutamyl transpeptidase Hofmannophila pseudospretella isopeptidase,keratinophagous nutritional ecology

Evaluation of the Heat,Entropy,and Rotational Changes Produced by Gravitational Segregation during Core Formation

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Journal of Earth Science 2015年第1期26卷 124-133页

作者： Anne m.Hofmeister robert E.Criss Department of Earth and Planetary Sciences Washington University

Core formation by gravitational segregation allegedly released sufficient interior heat to melt the Earth. Analysis of the energetics, which compare gravitational potential energy （Ug） of a fictitious, homogeneous reference state to Earth＇s current layered configuration, needs updating to correct errors and omissions, and to accommodate recent findings：（1） An erroneous positive sign was used for Ug while maintaining the reference value of 0 at infinity, which results in an incorrect sign fur AUg, which is crucial in determining whether a process is endothermic or exothermic. （2） The value of Ug for Earth＇s initial state is uncertain. （3） Recent meteorite evidence indicates that core formation began before the Earth was full-sized, which severely limits AUg. （4） Inhomogeneous accretion additionally reduced AUg. （5） The potentially large effect of differential rotation between the core and the mantle was not accounted for. （6） Entropy changes associated with creating order were neglected. Accordingly, we revise values of Ug, evaluate uncertainties, and show that AUg was converted substantially to eonfigurational energy （TAS）. These considerations limit the large sources of primordial heat to impacts and radioactivity. Although these processes may play a role in core formation, their energies are independent of gravitational segregation, which produces order and rotational energy, not internal heat. Instead, gravitational segregation promotes planetary cooling mainly because it segregates lithophilic radioactive elements upward, increasing surface heat flux while shortening the distance over which radiogenic heat diffuses outwards.

关键词： core formation primordial heat configurational energy thermodynamics rotational energy.

Diagnosis and management of testosterone deficiency

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Asian Journal of Andrology 2015年第2期17卷 177-186,I0006页

作者： James A mcBride Culley C Carson robert m Coward Department of Urology University of North Carolina School of Medicine NC USA.

Testosterone supplementation therapy （TST） use has dramatically increased over the past decade, due to the availability of newer agents, aggressive marketing, and an increasing incidence of testosterone deficiency （TD）. Despite the increase in TST, a degree of ambiguity remains as to the exact diagnostic criteria of TD, and administration and monitoring of TST. One explanation for this phenomenon is the complex role testosterone plays in multiple physiologic pathways. Numerous medical co-morbidities and medications can alter testosterone levels resulting in a wide range of nonspecific clinical signs and symptoms of TD. The diagnosis is also challenging due to the lack of a definitive serum total testosterone level that reliably correlates with symptoms. This observation is particularly true in the aging male and is exacerbated by inconsistencies between different laboratory assays. Several prominent medical societies have developed guideline statements to clarify the diagnosis, but they differ from each other and with expert opinion in several ways. Aside from diagnostic dilemmas, there are numerous subtle advantages and disadvantages of the various testosterone agents to appreciate. The available TST agents have changed significantly over the past decade similar to the trends in the diagnosis of TD. Therefore, as the usage of TST increases, clinicians will be challenged to maintain an up-to-date understanding of TD and TST. The purpose of this review is to provide a clear description of the current strategies for diagnosis and management of TD.

关键词： androgens erectile dysfunction hormones hypogonadism testosterone

The heterogeneity of store-operated calcium entry in melanoma

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Science China(Life Sciences) 2016年第8期59卷 764-769页

作者： robert Hooper m.Raza Zaidi Jonathan Soboloff Fels Institute for Cancer Research and molecular Biology Lewis Katz School of Medicine at Temple University Department of medical Genetics & molecular Biochemistry Lewis Katz School of Medicine at Temple University

Calcium is a key regulator of many physiological processes that are perturbed in cancer, such as migration, proliferation and apoptosis. The proteins STIm and Orai mediate store-operated calcium entry(SOCE), the main pathway for calcium entry in non-excitable cells. Changes in the expression and function of STIm and Orai have been found in a range of cancer types and thus implicated in disease progression. Here we discuss the role of STIm, Orai and the SOCE pathway in the progression of melanoma and explore how the heterogeneous nature of melanoma may explain the lack of consensus in the field regarding the role of SOCE in the progression of this disease.

关键词： melanoma STIm1 Orail metastasis