Now showing items 5652-5671 of 13755

    • Investigation of a Monte Carlo simulation and an analytic-based approach for modeling the system response for clinical I-123 brain SPECT imaging

      Auer, Benjamin; Zeraatkar, Navid; De Beenhouwer, Jan; Kalluri, Kesava; Kuo, Philip; Furenlid, Lars R.; King, Michael A.; Univ Arizona, Dept Med Imaging (SPIE-INT SOC OPTICAL ENGINEERING, 2019-05-28)
      The use of accurate system response modeling has been proven to be an essential key of SPECT image reconstruction, with its usage leading to overall improvement of image quality. The aim of this work was to investigate the imaging performance using an XCAT brain perfusion phantom of two modeling strategies, one based on analytic techniques and the other one based on GATE Monte-Carlo simulation. In addition, an efficient forced detection approach to improve the overall simulation efficiency was implemented and its performance was evaluated. We demonstrated that accurate modeling of the system matrix generated by Monte-Carlo simulation for iterative reconstruction leads to superior performance compared to analytic modeling in the case of clinical I-123 brain imaging. It was also shown that the use of the forced detection approach provided a quantitative and qualitative enhancement of the reconstruction.
    • Investigation of a possible malaria epidemic in an illegal gold mine in French Guiana: an original approach in the remote Amazonian forest

      Douine, Maylis; Sanna, Alice; Hiwat, Helene; Briolant, Sébastien; Nacher, Mathieu; Belleoud, Didier; Le Tourneau, François Michel; Bogreau, Hervé; De Laval, Franck; Univ Arizona, IGLOBES (BMC, 2019-03-22)
      Background: In April 2017, Suriname's Ministry of Health alerted French Guiana's Regional Health Agency (RHA) about an increase of imported malaria cases among people coming from an illegal gold mining site called Sophie, in French Guiana, a French overseas territory located in the Amazonian forest. Methods: Due to safety issues and the remoteness of Sophie, the RHA requested the collaboration of the French Armed Forces for the epidemiological investigation. A medical unit, and six soldiers to ensure the security of the mission, were transported by helicopter. Results: During the investigation, two malaria episodes were diagnosed among 46 persons. Twenty-six of them were from Sophie, where PCR-Plasmodium prevalence was estimated at 60% (15/26). This result was concordant with previous studies revealing high malaria endemicity in the gold miner population. The increase of imported cases in Suriname may have resulted from decreased access to under-the-counter anti-malarials and increased migration of gold miners to Suriname following a decline of the profitability of gold mining in a context of increased repression against illegal mining by the French army. Conclusion: This investigation of a suspicious malaria epidemic confirms the importance of malaria among illegal gold miners. Their mobility along the Guiana Shield and their health-seeking behaviour are likely to spread malaria in populations for which significant efforts are undertaken to fight against this disease. Fighting malaria in this population remains more relevant than ever. A pilot study (Malakit project) is currently in progress to evaluate the efficacy of kits for self-diagnosis and self-treatment.
    • Investigation of aerosol-cloud interactions under different absorptive aerosol regimes using Atmospheric Radiation Measurement (ARM) southern Great Plains (SGP) ground-based measurements

      Zheng, Xiaojian; Xi, Baike; Dong, Xiquan; Logan, Timothy; Wang, Yuan; Wu, Peng; Univ Arizona, Dept Hydrol & Atmospher Sci (COPERNICUS GESELLSCHAFT MBH, 2020-03-24)
      The aerosol indirect effect on cloud microphysical and radiative properties is one of the largest uncertainties in climate simulations. In order to investigate the aerosol-cloud interactions, a total of 16 low-level stratus cloud cases under daytime coupled boundary-layer conditions are selected over the southern Great Plains (SGP) region of the United States. The physicochemical properties of aerosols and their impacts on cloud microphysical properties are examined using data collected from the Department of Energy Atmospheric Radiation Measurement (ARM) facility at the SGP site. The aerosol-cloud interaction index (ACI(r)) is used to quantify the aerosol impacts with respect to cloud-droplet effective radius. The mean value of ACI(r) calculated from all selected samples is 0.145 +/- 0.05 and ranges from 0.09 to 0.24 at a range of cloud liquid water paths (LWPs; LWP = 20-300 g m(-2)). The magnitude of ACI(r) decreases with an increasing LWP, which suggests a diminished cloud microphysical response to aerosol loading, presumably due to enhanced condensational growth processes and enlarged particle sizes. The impact of aerosols with different light-absorbing abilities on the sensitivity of cloud microphysical responses is also investigated. In the presence of weak light-absorbing aerosols, the low-level clouds feature a higher number concentration of cloud condensation nuclei (N-CCN) and smaller effective radii (r(e)), while the opposite is true for strong light-absorbing aerosols. Furthermore, the mean activation ratio of aerosols to CCN (N-CCN/N-a) for weakly (strongly) absorbing aerosols is 0.54 (0.45), owing to the aerosol microphysical effects, particularly the different aerosol compositions inferred by their absorptive properties. In terms of the sensitivity of cloud-droplet number concentration (N-d) to N-CCN, the fraction of CCN that converted to cloud droplets (N-d/N-CCN) for the weakly (strongly) absorptive regime is 0.69 (0.54). The measured ACI(r) values in the weakly absorptive regime are relatively higher, indicating that clouds have greater microphysical responses to aerosols, owing to the favorable thermodynamic condition. The reduced ACI(r) values in the strongly absorptive regime are due to the cloud-layer heating effect induced by strong light-absorbing aerosols. Consequently, we expect larger shortwave radiative cooling effects from clouds in the weakly absorptive regime than those in the strongly absorptive regime.
    • Investigation of Charon's Craters With Abrupt Terminus Ejecta, Comparisons With Other Icy Bodies, and Formation Implications

      Robbins, Stuart J.; Runyon, Kirby; Singer, Kelsi N.; Bray, Veronica J.; Beyer, Ross A.; Schenk, Paul; McKinnon, William B.; Grundy, William M.; Nimmo, Francis; Moore, Jeffrey M.; et al. (AMER GEOPHYSICAL UNION, 2018-01)
      On the moon and other airless bodies, ballistically emplaced ejecta transitions from a thinning, continuous inner deposit to become discontinuous beyond approximately one crater radius from the crater rim and can further break into discrete rays and secondary craters. In contrast, on Mars, ejecta often form continuous, distinct, and sometimes thick deposits that transition to a low ridge or escarpment that may be circular or lobate. The Martian ejecta type has been variously termed pancake, rampart, lobate, or layered, and in this work we refer to it as abrupt termini ejecta (ATE). Two main formation mechanisms have been proposed, one requiring interaction of the ejecta with the atmosphere and the other mobilization of near-surface volatiles. ATE morphologies are also unambiguously seen on Ganymede, Europa, Dione, and Tethys, but they are not as common as on Mars. We have identified up to 38 craters on Charon that show signs of ATE, including possible distal ramparts and lobate margins. These ejecta show morphologic and morphometric similarities with other moons in the solar system, which are a subset of the properties observed on Mars. From comparison of these ejecta on Charon and other solar system bodies, we find the strongest support for subsurface volatile mobilization and ejecta fluidization as the main formation mechanism for the ATE, at least on airless, icy worlds. This conclusion comes from the bodies on which they are found, an apparent preference for certain terrains, and the observation that craters with ATE can be near to similarly sized craters that only have gradational ejecta.
    • Investigation of confocal microscopy for differentiation of renal cell carcinoma versus benign tissue. Can an optical biopsy be performed?

      Phung, Michael C.; Rouse, Andrew R.; Pangilinan, Jayce; Bell, Robert C.; Bracamonte, Erika R.; Mashi, Sharfuddeen; Gmitro, Arthur F.; Lee, Benjamin R.; Univ Arizona, Dept Urol, Coll Med; Univ Arizona, Dept Med Imaging, Coll Med; et al. (ELSEVIER SINGAPORE PTE LTD, 2020-10)
      Objective: Novel optical imaging modalities are under development with the goal of obtaining an "optical biopsy" to efficiently provide pathologic details. One such modality is confocal microscopy which allows in situ visualization of cells within a layer of tissue and imaging of cellular-level structures. The goal of this study is to validate the ability of confocal microscopy to quickly and accurately differentiate between normal renal tissue and cancer. Methods: Specimens were obtained from patients who underwent robotic partial nephrectomy for renal mass. Samples of suspected normal and tumor tissue were extracted from the excised portion of the kidney and stained with acridine orange. The stained samples were imaged on a Nikon E600 C1 Confocal Microscope. The samples were then submitted for hematoxylin and eosin processing and read by an expert pathologist to provide a gold-standard diagnosis that can later be compared to the confocal images. Results: This study included 11 patients, 17 tissue samples, and 118 confocal images. Of the 17 tissue samples, 10 had a gold-standard diagnosis of cancer and seven were benign. Of 118 confocal images, 66 had a gold-standard diagnosis of cancer and 52 were benign. Six confocal images were used as a training set to train eight observers. The observers were asked to rate the test images on a six point scale and the results were analyzed using a web based receiver operating characteristic curve calculator. The average accuracy, sensitivity, specificity, and area under the empirical receiver operating characteristic curve for this study were 91%, 98%, 81%, and 0.94 respectively. Conclusion: This preliminary study suggest that confocal microscopy can be used to distinguish cancer from normal tissue with high sensitivity and specificity. The observers in this study were trained quickly and on only six images. We expect even higher performance as observers become more familiar with the confocal images. (C) 2020 Editorial Office of Asian Journal of Urology. Production and hosting by Elsevier B.V.
    • Investigation of frequency-dependent attenuation coefficients for multiple solids using a reliable pulse-echo ultrasonic measurement technique

      Zhang, Guangdong; Li, Xiongbing; Zhang, Shuzeng; Kundu, Tribikram; Department of Civil & Architectural Engineering & Mechanics, University of Arizona (Elsevier B.V., 2021-03-14)
      A well-established narrowband pulse-echo technique is employed and improved further to investigate the frequency-dependent ultrasonic wave attenuation in various solids. During attenuation coefficient measurement, the diffraction correction is introduced to minimize wave beam-spreading loss, and frequency domain signals are used to minimize both the effects of downward shift of frequency and the error in determining the amplitude of time-domain signals. The frequency-dependent attenuation curves for 19 frequently-used solid materials are obtained using this method in the frequency range 1–25 MHz. It is observed from the measurement results of these materials that the attenuation can vary linearly or nonlinearly with the signal frequency, and the potential impact factors of the attenuation-frequency relationship are discussed. The experimental results presented in this paper is expected to provide a good reference for researchers interested in developing and using frequency-dependent attenuation coefficients of materials that are currently missing in the literature. © 2021 Elsevier Ltd
    • Investigation of ion-ion interaction effects on Yb3+-doped fiber amplifiers

      Wu, Jingwei; Zhu, Xiushan; Xia, Chun; Wei, Hua; Wiersma, Kort; Li, Michael; Zong, Jie; Chavez-Pirson, Arturo; Norwood, R. A.; Peyghambarian, N.; et al. (OPTICAL SOC AMER, 2019-09-19)
      Ytterbium (Yb3+)-doped materials have been widely used for high efficiency high energy laser sources at the 1 mu m wavelength region because of their very low quantum defect and the unique simple energy level structure of Yb3+, resulting in no excited-state absorption and low occurrence probability of deleterious ion-ion interaction processes. It has been generally recognized that these ion-ion interaction processes have very little influence on the operation of Yb3+-doped fiber lasers at low and moderate power levels. However, our recent study shows that the performance of Yb3+-doped fiber amplifiers operating at low power levels is still influenced by the ion-ion interaction processes due to the large amount of population at the upper laser level F-2(5/2). In this paper, experimental evidences of the ion-ion interaction effects in Yb3+-doped fiber amplifiers are presented and a new model including these effects is developed for the numerical simulation. Our experimental and numerical investigations on the 976 nm and 1030 nm Yb3+-doped silica and phosphate fiber amplifiers show that ion-ion interaction has non-negligible impact on the performance of Yb3+-doped fiber amplifiers indeed, and compared to Yb3+-doped silica fibers, Yb3+-doped phosphate fibers suffer much less from the ion-ion interaction effects due to the much less clustered ions. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
    • Investigation of Karst Spring Flow Cessation Using Grey System Models

      Guo, Yaru; Yeh, Tian-Chyi Jim; Hao, Yonghong; Univ Arizona, Dept Hydrol & Water Resources (MDPI, 2019-09-15)
      Karst aquifers are prominent sources of water worldwide; they store large amounts of water and are known for their beautiful springs. However, extensive groundwater development and climate variation has resulted in a decline in the flow of most karst springs; some have even dried up. In order to obtain a better understanding of the factors contributing to this development, this study introduced grey system models, which quantified spring flow, taking Jinci Springs (China), which dried up in May 1994, as an example. Based on the characteristics of Jinci Springs, spring flow was divided into two stages: first (1954–1960), when the spring flow was affected only by climate variation; and second (1961–1994), when the flow was impacted by both climate variation and anthropogenic activities. The results showed that Jinci Springs flow had a strong relationship with precipitation occurring one year and three years earlier in the first stage. Subsequently, a grey system GM (1,3) model with one-year and three-year lags was set up for the first stage. By using the GM (1,3) model, we simulated the spring flow in the second stage under effects of climate variation only. By subtracting the observed spring flow from the simulated flow, we obtained the contribution of anthropogenic activities to Jinci Springs’ cessation. The contribution of anthropogenic activities and climate variation to the decline was 1.46 m3/s and 0.62 m3/s, respectively. Finally, each human activity that caused the decline was estimated. The methods devised herein can be used to describe karst hydrological processes that are under the effects of anthropogenic activities and climate variation.
    • An investigation of perceived vehicle speed from a driver's perspective

      Wu, Changxu; Yu, Dekuang; Doherty, Amy; Zhang, Tianyi; Kust, Leo; Luo, Gang; Univ Arizona (PUBLIC LIBRARY SCIENCE, 2017-10-17)
      Purpose Speed estimation of drivers' own vehicles and other vehicles on the road is an important task for drivers and is also crucial to the roadway safety. The objective of the study was to examine the effects of multiple factors such as image scale, speed, road type, driving experience, and gender on the speed perception of drivers' own vehicles. Methods Thirty participants consisted of 17 males and 13 females, including 13 without driving experience. All participants estimated the driving speed of 192 5-second video clips, which were selected from naturalistic driving recordings. The recorded driving speeds were evenly distributed across the entire range from 5mph to 65mph. Half of the selected video clips were recorded on wide roads and another half were recorded on comparatively narrow roads. Video clips were played on a large screen, with each clip shown in one of 4 image scales (100%, 75%, 50%, and 38% of the actual field of view in the real world). Results Speed estimates were most accurate for the smallest image size (38% of the actual field of view). As the image size increased, the driving speed was increasingly underestimated. Participants with driving experience accurately estimated the driving speed on both wide and narrow roads whereas those without driving experience had greater underestimates on wider roads. Speeds were most accurately estimated within the range 25-35mph, but the speeds slower than the range tend to be overestimated and the speeds faster than the range are more likely to be underestimated. While males and females showed the same pattern across speed groups, females have greater estimation errors at the highest and lowest speed groups. Participants without driving experience showed increasing underestimation of speed as driving speed increased whereas participants with driving experience primarily underestimated the highest speeds. Conclusions The present study shows the effect of multidimensional influential factors on perceived vehicle speed from drivers' perspective. The results also have implications for driving simulation scenario design, driving simulator setup, and the assessment of speed control in simulated and naturalistic environments.
    • INVESTIGATION OF PRIMORDIAL BLACK HOLE BURSTS USING INTERPLANETARY NETWORK GAMMA-RAY BURSTS

      Ukwatta, T. N.; Hurley, K.; MacGibbon, J. H.; Svinkin, D. S.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Pal'shin, V. D.; Goldsten, J.; Boynton, W.; et al. (IOP PUBLISHING LTD, 2016-07-25)
      The detection of a gamma-ray burst (GRB) in the solar neighborhood would have very important implications for GRB phenomenology. The leading theories for cosmological GRBs would not be able to explain such events. The final bursts of evaporating primordial black holes (PBHs), however, would be a natural explanation for local GRBs. We present a novel technique that can constrain the distance to GRBs using detections from widely separated, non-imaging spacecraft. This method can determine the actual distance to the burst if it is local. We applied this method to constrain distances to a sample of 36 short-duration GRBs detected by the Interplanetary Network (IPN) that show observational properties that are expected from PBH evaporations. These bursts have minimum possible distances in the 10(13)-10(18) cm (7-10(5) au) range, which are consistent with the expected PBH energetics and with a possible origin in the solar neighborhood, although none of the bursts can be unambiguously demonstrated to be local. Assuming that these bursts are real PBH events, we estimate lower limits on the PBH burst evaporation rate in the solar neighborhood.
    • Investigation of Seed Germination Indices for Early Selection of Salinity Tolerant 1 Genotypes: A Case Study in Wheat

      Aflaki, Fatemeh; Sedghi, Mohammad; Pazuki, Arman; Pessarakli, Mohammad; Univ Arizona, Sch Plant Sci (United Arab Emirates University, 2017-03)
      Plant establishment is highly correlated with successful germination and seedling growth, the most sensitive and critical stages. Abiotic stresses by their limiting and adverse effects on these stages finally result in poor yield. Therefore, investigating resistance to salinity among genotypes of a desired plant is highly recommended for anticipated drought seasons. To study the effects of salinity on seed germination and initial growth of seedlings, a factorial experiment was conducted based on a completely randomized design with four replicates using three wheat (Triticum aestivum) genotypes (Zagros, Gascogen and Kuhdasht). Salinity levels included 0 (control), 3.5, and 7 dS m-1 (deci-Siemens per meter). The results indicated that salinity had a significant influence on different germination indices (P<0.05). In all the genotypes, with an increase in salinity levels, indices including germination percentage, germination rate, seed vigor, coefficient of germination rate, coleoptile to plumule ratio, and daily germination mean decreased. Unlike the mentioned indices, the ratio of the radicle to plumule and the mean of germination time increased. Zagros genotype showed more tolerant than the other two. Based on these results, it seems that germination indices may be effectively used in selecting tolerant plants to salinity stress.
    • Investigation of Single-Case Multiple-Baseline Randomization Tests of Trend and Variability

      Levin, Joel R.; Ferron, John M.; Gafurov, Boris S.; Univ Arizona (Springer Science and Business Media LLC, 2020-08-04)
      Previous simulation studies of randomization tests applied in single-case educational intervention research contexts have typically focused on A-to-B phase changes in means/levels. In the present simulation study, we report the results of two multiple-baseline investigations, one targeting between-phase changes in slopes/trends and the other targeting between-phase changes in variability. For each of these measures, we examine the comparative type I errors and powers of several randomization test procedures that have previously appeared in the literature. In so doing, we propose an alternative measure of variability that is more sensitive to detecting between-phase change than is the variance itself. We conclude by providing a summary table of recommended randomization test procedures for assessing different types of intervention-based effects associated with level, trend, and variability.
    • Investigation of tetracosane thermal transport in presence of graphene and carbon nanotube fillers––A molecular dynamics study

      Tafrishi, Hossein; Sadeghzadeh, Sadegh; Ahmadi, Rouhollah; Molaei, Fatemeh; Yousefi, Farrokh; Hassanloo, Hamidreza; Univ Arizona, Min & Geol Engn Dept (ELSEVIER, 2020-06)
      This paper examines the thermal properties of pure tetracosane paraffin, tetracosane-graphene, and tetracosanecarbon nanotube mixed phase change materials (PCM). The most important properties studied were thermal capacity in constant volume (Cv), mean square displacement of atoms (MSD), radial distribution function (RDF), density, phonon density of states (PDOS) and thermal conductivity (k) under different temperatures. The results show that graphene and carbon nanotube increase the thermal conductivity of the tetracosane at different temperatures, but decrease the molecular movement and its thermal capacity (except after about 360 K), and it can be said that this slightly decreases the paraffin melting temperature. It was demonstrated that carbon nanotube is more efficient than graphene to increase the thermal conductivity of the proposed PCM.
    • Investigation of the Influence of Leaf Thickness on Canopy Reflectance and Physiological Traits in Upland and Pima Cotton Populations

      Pauli, Duke; White, Jeffrey W.; Andrade-Sanchez, Pedro; Conley, Matthew M.; Heun, John; Thorp, Kelly R.; French, Andrew N.; Hunsaker, Douglas J.; Carmo-Silva, Elizabete; Wang, Guangyao; et al. (FRONTIERS MEDIA SA, 2017-08-17)
      Many systems for field-based, high-throughput phenotyping (FB-HTP) quantify and characterize the reflected radiation from the crop canopy to derive phenotypes, as well as infer plant function and health status. However, given the technology's nascent status, it remains unknown how biophysical and physiological properties of the plant canopy impact downstream interpretation and application of canopy reflectance data. In that light, we assessed relationships between leaf thickness and several canopy-associated traits, including normalized difference vegetation index (NDVI), which was collected via active reflectance sensors carried on a mobile FB-HTP system, carbon isotope discrimination (CID), and chlorophyll content. To investigate the relationships among traits, two distinct cotton populations, an upland (Gossypium hirsutum L.) recombinant inbred line (RIL) population of 95 lines and a Pima (G, barbaderise L.) population composed of 25 diverse cultivars, were evaluated under contrasting irrigation regimes, water-limited (WL) and well-watered pm conditions, across 3 years. We detected four quantitative trait loci (QTL) and significant variation in both populations for leaf thickness among genotypes as well as high estimates of broad-sense heritability (on average, above 0.7 for both populations), indicating a strong genetic basis for leaf thickness. Strong phenotypic correlations (maximum r = -0.73) were observed between leaf thickness and NDVI in the Pima population, but not the RIL population. Additionally, estimated genotypic correlations within the RIL population for leaf thickness with CID, chlorophyll content, and nitrogen discrimination (r(gij) = -0.32, 0.48, and 0.40, respectively) were all significant under WW but not WL conditions. Economically important fiber quality traits did not exhibit significant phenotypic or genotypic correlations with canopy traits. Overall, our results support considering variation in leaf thickness as a potential contributing factor to variation in NDVI or other canopy traits measured via proximal sensing, and as a trait that impacts fundamental physiological responses of plants.
    • Investigation of the inner structures around HD 169142 with VLT/SPHERE

      Ligi, R.; Vigan, A.; Gratton, R.; de Boer, J.; Benisty, M.; Boccaletti, A.; Quanz, S. P.; Meyer, M.; Ginski, C.; Sissa, E.; et al. (OXFORD UNIV PRESS, 2018-01)
      We present observations of the Herbig Ae star HD 169142 with the VLT/SPHERE instruments InfraRed Dual-band Imager and Spectrograph (IRDIS) (K1K2 and H2H3 bands) and the Integral Field Spectrograph (IFS) (Y, J and H bands). We detect several bright blobs at similar to 180 mas separation from the star, and a faint arc-like structure in the IFS data. Our reference differential imaging (RDI) data analysis also finds a bright ring at the same separation. We show, using a simulation based on polarized light data, that these blobs are actually part of the ring at 180 mas. These results demonstrate that the earlier detections of blobs in the H and K-S bands at these separations in Biller et al. as potential planet/substellar companions are actually tracing a bright ring with a Keplerian motion. Moreover, we detect in the images an additional bright structure at similar to 93 mas separation and position angle of 355 degrees, at a location very close to previous detections. It appears point-like in the YJ and K bands but is more extended in the H band. We also marginally detect an inner ring in the RDI data at similar to 100 mas. Follow-up observations are necessary to confirm the detection and the nature of this source and structure.
    • Investigation of thermal properties of crystalline alpha quartz by employing different interatomic potentials: A molecular dynamic study

      Molaei, Fatemeh; Moghadam, Mostafa Safdari; Nouri, Shahrzad; Mining and Geological Engineering Department, The University of Arizona (Elsevier BV, 2021-07)
      In the present work, the thermal properties of crystalline α-quartz, including thermal conductivity (TC) and thermal expansion coefficient (TEC), are studied using the non-equilibrium molecular dynamics (NEMD) simulation method. Since there is a dependence on interatomic potentials in simulation results, the thermal conductivity and thermal expansion coefficient of crystalline α- quartz is computed using various force fields in a temperature range from 200 K to 1000 K compare which concurs better with experimental findings. Arising from the present molecular dynamic simulation by different force fields such as Tersoff, Vashishta, Stillinger-Weber, Meam, BKS, ReaxFF, and Morse, the thermal conductivities that were carried out using the ReaxFF and BKS are more accurate. It is also founded that predicted thermal conductivity at higher temperatures shows a better agreement with experimental values. In terms of TEC, Tersoff and SW corroborate the experimental remarks and give a smaller magnitude of TEC in z direction. On the other hand, in contradiction with the other force fields, Meam potential presents no significant TEC variation with temperature alteration. © 2021 Elsevier B.V.
    • Invisible water: the importance of good groundwater governance and management

      Megdal, Sharon B.; Univ Arizona, Water Resources Res Ctr (NATURE PUBLISHING GROUP, 2018-09-03)
      This paper summarizes the results of efforts to bring attention to the importance of understanding and improving groundwater governance and management. Discussion of survey work in the United States and global case studies highlights the importance of focusing attention on this invisible water resource before pollution or depletion of it causes severe economic, environmental, and social dislocations. Better governance and management of groundwater are required to move toward sustainable groundwater use.
    • Involvement of a specificity proteins-binding element in regulation of basal and estrogen-induced transcription activity of the BRCA1 gene

      Hockings, Jennifer; Degner, Stephanie; Morgan, Sherif; Kemp, Michael; Romagnolo, Donato; Cancer Biology Interdisciplinary Graduate Program, Department of Nutritional Sciences, The University of Arizona, E 4th Street, Tucson, Arizona 85721-0038, USA; Laboratory of Mammary Gland Biology, Department of Nutritional Sciences, The University of Arizona, E 4th Street, Tucson, Arizona 85721-0038, USA (BioMed Central, 2008)
      INTRODUCTION:Increased estrogen level has been regarded to be a risk factor for breast cancer. However, estrogen has also been shown to induce the expression of the tumor suppressor gene, BRCA1. Upregulation of BRCA1 is thought to be a feedback mechanism for controlling DNA repair in proliferating cells. Estrogens enhance transcription of target genes by stimulating the association of the estrogen receptor (ER) and related coactivators to estrogen response elements or to transcription complexes formed at activator protein (AP)-1 or specificity protein (Sp)-binding sites. Interestingly, the BRCA1 gene lacks a consensus estrogen response element. We previously reported that estrogen stimulated BRCA1 transcription through the recruitment of a p300/ER-alpha complex to an AP-1 site harbored in the proximal BRCA1 promoter. The purpose of the study was to analyze the contribution of cis-acting sites flanking the AP-1 element to basal and estrogen-dependent regulation of BRCA1 transcription.METHODS:Using transfection studies with wild-type and mutated BRCA1 promoter constructs, electromobility binding and shift assays, and DNA-protein interaction and chromatin immunoprecipitation assays, we investigated the role of Sp-binding sites and cAMP response element (CRE)-binding sites harbored in the proximal BRCA1 promoter.RESULTS:We report that in the BRCA1 promoter the AP-1 site is flanked upstream by an element (5'-GGGGCGGAA-3') that recruits Sp1, Sp3, and Sp4 factors, and downstream by a half CRE-binding motif (5'-CGTAA-3') that binds CRE-binding protein. In ER-alpha-positive MCF-7 cells and ER-alpha-negative Hela cells expressing exogenous ER-alpha, mutation of the Sp-binding site interfered with basal and estrogen-induced BRCA1 transcription. Conversely, mutation of the CRE-binding element reduced basal BRCA1 promoter activity but did not prevent estrogen activation. In combination with the AP-1/CRE sites, the Sp-binding domain enhanced the recruitment of nuclear proteins to the BRCA1 promoter. Finally, we report that the MEK1 (mitogen-activated protein kinase kinase-1) inhibitor PD98059 attenuated the recruitment of Sp1 and phosphorylated ER-alpha, respectively, to the Sp and AP-1 binding element.CONCLUSION:These cumulative findings suggest that the proximal BRCA1 promoter segment comprises cis-acting elements that are targeted by Sp-binding and CRE-binding proteins that contribute to regulation of BRCA1 transcription.
    • Involvement of T-type calcium channels in the mechanism of low dose morphine-induced hyperalgesia in adult male rats

      Abbasloo, Elham; Abdollahi, Farzaneh; Saberi, Arezoo; Esmaeili-Mahani, Saeed; Kaeidi, Ayat; Akhlaghinasab, Fereshteh; Sheibani, Vahid; Thomas, Theresa Currier; Kobeissy, Firas Hosni; Oryan, Shahrbanoo; et al. (Elsevier BV, 2021-12)
      It has been shown that systemic and local administration of ultra-low dose morphine induced a hyperalgesic response via mu-opioid receptors. However, its exact mechanism(s) has not fully been clarified. It is documented that mu-opioid receptors functionally couple to T-type voltage dependent Ca+2 channels. Here, we investigated the role of T-type calcium channels, amiloride and mibefradil, on the induction of low-dose morphine hyperalgesia in male Wistar rats. The data showed that morphine (0.01 μg i.t. and 1 μg/kg i.p.) could elicit hyperalgesia as assessed by the tail-flick test. Administration of amiloride (5 and 10 μg i.t.) and mibefradil (2.5 and 5 μg i.t.) completely blocked low-dose morphine-induced hyperalgesia in spinal dorsal horn. Amiloride at doses of 1 and 5 mg/kg (i.p.) and mibefradil (9 mg/kg ip) 10 min before morphine (1 μg/kg i.p.) inhibited morphine-induced hyperalgesia. Our results indicate a role for T-type calcium channels in low dose morphine-induced hyperalgesia in rats.
    • Involving Police Departments in Early Awareness of Concussion Symptoms during Domestic Violence Calls

      Higbee, Mark; Eliason, Jon; Weinberg, Hilary; Lifshitz, Jonathan; Handmaker, Hirsch; Univ Arizona, Dept Child Hlth, Coll Med Phoenix; Univ Arizona, Dept Radiol, Coll Med (ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2019-08-19)
      Police officers around the world respond to and investigate calls regarding domestic violence (DV) daily. Police departments operate with standard protocols, particularly when engaging in investigations that involve allegations of strangulation or sexual assault. Operating under advisement of the Maricopa County Attorney’s Office, the Mesa Police Department (Mesa, AZ) has established protocols for detecting, recording, and prosecuting DV cases that involve strangulation and sexual assault. Allegations of strangulation (defined as impeded breathing) or sexual assault prompt officers to offer a forensic nursing exam (FNE) combined with strangulation treatment by forensic nurses at the Mesa Family Advocacy Center. Recognizing the potential for head injury to the assault victim in all DV situations, including intimate partner violence (IPV), the police department has added concussion-awareness training, as well as a point-of-incident investigative tool for its officers to record neurological function of the victim. Officers were instructed to use the ConQVerge device to measure and record the Near Point of Convergence (NPC) as a test of neurological impairment in suspected head injuries. In this article, we discuss the challenges and opportunities for assisting victims of DV strangulation and sexual assault (including non-DV sexual assault) with on-site assessment and consent for further medical assessment and treatment. Additionally, rates of domestic assault victims that report a crime, but decline to follow through with forensic medical tests, are reported for the first time. Lessons learned from the project that inform strategic operations in this space are offered to other agencies prior to the implementation of similar procedures.