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The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

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neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis H.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA national Institutes of Health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

Inorganic arsenic： A non-genotoxic carcinogen

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Journal of Environmental Sciences 2016年第11期28卷 28-37页

作者： samuel M.cohen Aparajita Chowdhury Lora L.Arnold Department of Pathology and Microbiology University of Nebraska Medical Center Omaha NE 68198-3135 USA.

Inorganic arsenic induces a variety of toxicities including cancer. The mode of action for cancer and non-cancer effects involves the metabolic generation of trivalent arsenicals and their reaction with sulfhydryl groups within critical proteins in various cell types which leads to the biological response. In epithelial cells, the response is cell death with consequent regenerative proliferation. If this continues for a long period of time, it can result in an increased risk of cancer. Arsenicals do not react with DnA. There is evidence for indirect genotoxicity in various in vitro and in vivo systems, but these involve exposures at cytotoxic concentrations and are not the basis for cancer development. The resulting markers of genotoxicity could readily be due to the cytotoxicity rather than an effect on the DnA itself. Evidence for genotoxicity in humans has involved detection of chromosomal aberrations, sister chromatid exchanges in lymphocytes and micronucleus formation in lymphocytes, buccal mucosal cells, and exfoliated urothelial cells in the urine. numerous difficulties have been identified in the interpretation of such results, including inadequate assessment of exposure to arsenic, measurement of micronuclei, and potential confounding factors such as tobacco exposure, folate deficiency, and others. Overall, the data strongly supports a non-linear dose response for the effects of inorganic arsenic. In various in vitro and in vivo models and in human epidemiology studies there appears to be a threshold for biological responses, including cancer.

关键词： Arsenic Cancer Genotoxicity Cytotoxicity Regeneration Cell proliferation

Multi-Model Communication and Data Assimilation for Mitigating Model Error and Improving Forecasts

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Chinese Annals of Mathematics,Series B 2019年第5期40卷 689-720页

作者： Yian CHEn samuel n.STECHMAnn Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Statistics University of ChicagoChicagoIL 60637USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Models for weather and climate prediction are complex, and each model typically has at least a small number of phenomena that are poorly represented, such as perhaps the Madden-Julian Oscillation(MJO for short) or El nino-Southern Oscillation(EnSO for short) or sea ice. Furthermore, it is often a very challenging task to modify and improve a complex model without creating new deficiencies. On the other hand, it is sometimes possible to design a low-dimensional model for a particular phenomenon, such as the MJO or EnSO, with significant skill, although the model may not represent the dynamics of the full weather-climate system. Here a strategy is proposed to mitigate these model errors by taking advantage of each model’s strengths. The strategy involves inter-model data assimilation, during a forecast simulation, whereby models can exchange information in order to obtain more faithful representations of the full weather-climate system. As an initial investigation, the method is examined here using a simplified scenario of linear models, involving a system of stochastic partial differential equations(SPDEs for short)as an imperfect tropical climate model and stochastic differential equations(SDEs for short) as a low-dimensional model for the MJO. It is shown that the MJO prediction skill of the imperfect climate model can be enhanced to equal the predictive skill of the lowdimensional model. Such an approach could provide a route to improving global model forecasts in a minimally invasive way, with modifications to the prediction system but without modifying the complex global physical model itself.

关键词： MJO Multi-Model communication Data assimilation Kalman filter algorithm

Mode of action for inorganic arsenic toxicity and carcinogenesis

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Chinese Science Bulletin 2014年第11期59卷 1078-1082页

作者： Puttappa R.Dodmane Lora L.Arnold samuel M.cohen Department of Pathology and Microbiology University of Nebraska Medical Center983135 Nebraska Medical Center

Inorganic arsenic(iAs) at high doses is a known human carcinogen, inducing tumors of the skin,urinary bladder, and lung. It is also associated with noncancer toxicities. An understanding of the mode of action(MOA) for arsenic-induced effects is needed to develop a scientifically-based risk assessment. To determine an MOA for iAs induced toxicities, it is necessary to understand the metabolism, kinetics, cell transport, and interaction with specific proteins of iAs. Based on in vitro investigations using animal and human cells, studies from animal models,and clinical and epidemiological studies, we have proposed an MOA involving formation of sufficient levels of reactive trivalent metabolites which interact with critical free sulfhydryl groups, leading to cytotoxicity and regenerative cell proliferation. There is a strong correlation between in vitro cytotoxicity([0.1 lmol/L trivalent arsenicals) and the no effect levels in rodents [approximately 1 ppm(1 ppm = 1 mg/L) of water or diet]. In epithelial target tissues, the cytotoxic effects of iAs result in chronic precursor lesions which have the potential for an increased risk of developing cancer. In non-epithelial tissues, noncancer toxicities such as hypertension and atherosclerosis develop. This MOA implies a non-linear, threshold dose–response relationship for both non-cancer and cancer end points of exposure to iAs.

关键词：体外细胞毒性致癌作用无机砷诱导效应会计准则氧化锌避雷器上皮组织动脉粥样硬化

Combining material characterization with single and multi-oxyanion adsorption for mechanistic study of chromate removal by cationic hydrogel

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Journal of Environmental Sciences 2011年第6期23卷 1004-1010页

作者： Irene M.C.Lo samuel C.n.Tang Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

Cationic hydrogel with magnetic property was synthesized via radical polymerization and its removal capacity of chromate from contaminated water was found to be 200 mg/*** Fourier transform infrared spectroscopy（FT-IR） study,the mechanism of chromate removal by hydrogel was found to be non-specific adsorption,mainly due to ion exchange,as evidenced by the positively charged functional group,trimethyl ammonium-n＋（CH3）3,in the *** were accordingly determined by testing di？erent oxyanion adsorption onto the *** results of the chromate adsorption experiments illustrated that the amount of chromate adsorbed was nearly equal to that of the chloride released from the hydrogel,which is part of the evidence for ion *** and multi-oxyanion adsorption experiments were also performed,and it was demonstrated that ion removal was species independent,but charge dependent,another characteristic of the ion exchange *** was found that the same Langmuir model can be applied to best fit the findings of single and multi-oxyanion adsorption,which further indicates the mechanism of chromate removal is attributed to ion *** view of the above,the background anions compete for adsorption sites with chromate,evidenced by inhibitive chromate removal in the presence of background electrolytes in the batch studies,further echoing the ion exchange mechanism.

关键词： adsorption magnetic hydrogel mechanism ion exchange oxyanion

Analytical modeling and simulation of germanium single gate silicon on insulator TFET

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Journal of Semiconductors 2014年第3期35卷 25-28页

作者： T.S.Arun samuel n.B.Balamurugan Department of Electronics and Communication Engineering Thiagarajar College of Engineering

This paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI TFET）. The parabolic approximation technique is used to solve the 2D Poisson equation with suitable boundary conditions and analytical expressions are derived for the surfacepotential,*** is derived further by using the electric fields. The results show that Ge based TFETs have significant improvements ***heanalytical model results with the technology computer aided design（TCAD） simulation results and also comparing them with results from a silicon based TFET.

关键词： tunnel field effect transistor(TFET) analytical modelling Poisson equation surface potential electric field

Balanced and Unbalanced Components of Moist Atmospheric Flows with Phase Changes

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Chinese Annals of Mathematics,Series B 2019年第6期40卷 1005-1038页

作者： Alfredo n.WETZEL Leslie M.SMITH samuel n.STECHMAnn Jonathan E.MARTIn Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Engineering Physics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Atmospheric variables(temperature, velocity, etc.) are often decomposed into balanced and unbalanced components that represent low-frequency and high-frequency waves, respectively. Such decompositions can be defined, for instance, in terms of eigenmodes of a linear operator. Traditionally these decompositions ignore phase changes of water since phase changes create a piecewise-linear operator that differs in different phases(cloudy versus non-cloudy). Here we investigate the following question: How can a balanced–unbalanced decomposition be performed in the presence of phase changes? A method is described here motivated by the case of small Froude and Rossby numbers,in which case the asymptotic limit yields precipitating quasi-geostrophic equations with phase changes. Facilitated by its zero-frequency eigenvalue, the balanced component can be found by potential vorticity(PV) inversion, by solving an elliptic partial differential equation(PDE), which includes Heaviside discontinuities due to phase changes. The method is also compared with two simpler methods: one which neglects phase changes, and one which simply treats the raw pressure data as a streamfunction. Tests are shown for both synthetic, idealized data and data from Weather Research and Forecasting(WRF) model simulations. In comparisons, the phase-change method and no-phase-change method produce substantial differences within cloudy regions, of approximately 5K in potential temperature, due to the presence of clouds and phase changes in the data. A theoretical justification is also derived in the form of a elliptic PDE for the differences in the two streamfunctions.

关键词： Potential vorticity inversion Moist atmospheric dynamics Slow-fast systems Balanced-unbalanced decomposition Elliptic partial differential equations

Mixtures of tetrakis hydroxymethyl phosphonium chloride and ammonium influence plankton community structure in blackwater pond mesocosms

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Emerging Contaminants 2020年第1期6卷 62-71页

作者： Marina n.Osier Risa A.cohen Department of Biology Georgia Southern UniversityPO Box 8042-1StatesboroGA30460USA

Mixtures of chemicals from human sources are pervasive in aquatic systems,yet their effects on aquatic communities are relatively *** contaminants such as organophosphorus flameretardants(*** hydroxymethyl phosphonium chloride(THPC)),are toxic to planktonic species at environmentally relevant ***,inorganic ammonium from agriculture and industry is likely to enter surface waters simultaneously with flame retardant *** effects of ammonium on plankton are known,its presence has the potential to influence the toxicity of other *** study mixture effects on plankton communities,floating mesocosms were dosed with THPC(0.08 or 0.8 mg L^-1)with or without ammonium(0.3 mg L^-1).Weekly measurements of zooplankton community composition and phytoplankton abundance(as chlorophyll a)were *** factor alone had no effect on zooplankton abundance or species ***,the mixture decreased the proportion of calanoid copepods and increased rotifers during weeks *** a was unaffected by treatments,but concentrations were highly variable for the duration of the *** interaction between THPC and ammonium suggests that the contaminants together reduce abundance of large zooplankton,releasing smaller zooplankton from predation and competitive pressure while potentially limiting food availability to planktivorous fish.

关键词： Emerging contaminant Flame retardant Freshwater nitrogen Phytoplankton Zooplankton Ecotoxicology

Hydration Assessment of Athletes

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中国运动医学杂志 2006年第2期25卷 238-244页

作者： samuel n.Cheuvront Michael n.Sawka Thermal and Mountain Medicine Division U. S . Army Research Institute of Environmental Medicine Natick USA

KEY POInTS Although there is no scientific consensus for 1 ） how best to assess the hydration status of athletes, 2）what criteria to use as acceptable outcome measurements, or 3） the best time to apply practical assessment methods, there are methods that can be used toprovide athletes with useful feedback about their hydration status.

关键词：运动员评价水合作用运动医学