17 research outputs found
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The Stopping of Energetic Si, P and S Ions in Ni, Cu, Ge and GaAs Targets
Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the stopping powers is the SRIM/TRIM program developed by Ziegler and coworkers. However, other researchers report that at times, these values differ significantly from experimental values. In this study the stopping powers of Si, P and S ions have been measured in Ni, Cu, Ge and GaAs absorbers in the energy range ~ 2-10 MeV. For elemental films of Ni, Cu and Ge, the stopping of heavy ions was measured using a novel ERD (Elastic Recoil Detection) based technique. In which an elastically recoiled lighter atom is used to indirectly measure the energy of the incoming heavy ion using a surface barrier detector. In this way it was possible to reduce the damage and to improve the FWHM of the detector. The results were compared to SRIM-2000 predictions and other experimental measurements. A new technique derived from Molecular Beam Epitaxy (MBE) was developed to prepare stoichiometric GaAs films on thin carbon films for use in transmission ion beam experiments. The GaAs films were characterized using X-ray Photoelectron Spectroscopy (XPS) and Particle Induced X-ray Emission (PIXE). These films were used to investigate the stopping powers of energetic heavy ions in GaAs and to provide data for the calculation of Bethe-Bloch parameters in the framework of the Modified Bethe-Bloch theory. As a result of this study, stopping power data are available for the first time for Si and P ions in the energy range 2-10 MeV stopping in GaAs absorbers
A Study of Double Diffusive Free Convection From a Corrugated Vertical Surface in a Darcy Porous Medium Under Soret and Dufour effects
This study examines the influence of Soret and Dufour effects on double diffusive free convection due to wavy vertical surface immersed in a fluid saturated semi-infinite porous medium under Darcian assumptions. A wavy to flat surface transformation is applied, and the resulting coupled nonlinear partial differential equations under Boussinesq approximation are reduced to boundary layer equations. A finite difference scheme based on the Keller-Box approach has been used in conjunction with block-tridiagonal solver for obtaining the solution for boundary layer equations. Results from the current study are compared with those available in literature. The effect of various parameters such as wave amplitude (a), Lewis number (Le), buoyancy ratio (B), and Soret (Sr) and Dufour (Df) numbers are analyzed through local and average Nusselt number, and local and average Sherwood number plots
Vampyren; en sexsymbol och ett blodtörstande monster : En jÀmförelse av beskrivningen av vampyrerna i Stephenie Meyers Twilight och Bram Stokers Dracula, kopplat till genre, berÀttarperspektiv och Äldersgrupp.
This essay discusses the differences in depiction of vampires between Stephenie Meyerâs Twilight (2005) and Bram Stokerâs Dracula (1897). By using examples from the novels, the essay exemplifies how genre, narration, and readership affect the description of vampires within the two novels. The essay bases its discussion on genre on the premise that the vampire genre is in fact a genre to itself, but one with a broad variation. Furthermore, the essay briefly discusses the shift within the vampire genre, where vampires during the last centuries have gone from dangerous and scary to appealing and romantic. A connection is made between the shift within the vampire genre and Anne Riceâs vampire fiction. The discussion on genre shows how the romance, fantasy, and horror genres affect the depiction of vampires.Denna uppsats diskuterar hur vampyrer i verken Twilight (Meyer, 2005) och Dracula (Stoker, 1897) skildras pĂ„ olika sĂ€tt. Skillnader i beskrivningarna illustreras med hjĂ€lp av exempel frĂ„n de bĂ„da böckerna och berör genre, berĂ€ttarperspektiv och lĂ€sarkrets. Diskussionen i uppsatsen baseras pĂ„ att vampyrgenren Ă€r en egen genre med mĂ„nga olika beskrivningar av vampyren. Uppsatsen berör Ă€ven förĂ€ndringen i genren och lyfter kort hur vampyren frĂ„n början tolkas som farlig och skrĂ€mmande för att sedan framstĂ„ som attraktiv och romantisk. En koppling görs ocksĂ„ mellan förĂ€ndringen i vampyrgenren och Anne Rices vampyrnoveller. Vidare i diskussionen kring genre berörs Ă€ven hur genrerna romantik, fantasy och skrĂ€ck pĂ„verkar skildringen av vampyrerna i de nĂ€mnda verken
Regulation of Human Endogenous Metabolites by Drug Transporters and Drug Metabolizing Enzymes: An Analysis of Targeted SNP-Metabolite Associations
Drug transporters and drug-metabolizing enzymes are primarily known for their role in the absorption, distribution, metabolism, and excretion (ADME) of small molecule drugs, but they also play a key role in handling endogenous metabolites. Recent cross-tissue co-expression network analyses have revealed a “Remote Sensing and Signaling Network” of multispecific, oligo-specific, and monospecific transporters and enzymes involved in endogenous metabolism. This includes many proteins from families involved in ADME (e.g., SLC22, SLCO, ABCC, CYP, UGT). Focusing on the gut−liver−kidney axis, we identified the endogenous metabolites potentially regulated by this network of ~1000 proteins by associating SNPs in these genes with the circulating levels of thousands of small, polar, bioactive metabolites, including free fatty acids, eicosanoids, bile acids, and other signaling metabolites that act in part via G-protein coupled receptors (GPCRs), nuclear receptors, and kinases. We identified 77 genomic loci associated with 7236 unique metabolites. This included metabolites that were associated with multiple, distinct loci, indicating coordinated regulation between multiple genes (including drug transporters and drug-metabolizing enzymes) of specific metabolites. We analyzed existing pharmacogenomic data and noted SNPs implicated in endogenous metabolite handling (e.g., rs4149056 in SLCO1B1) also affecting drug ADME. The overall results support the existence of close relationships, via interactions with signaling metabolites, between drug transporters and drug-metabolizing enzymes that are part of the Remote Sensing and Signaling Network, and with GPCRs and nuclear receptors. These analyses highlight the potential for drug−metabolite interactions at the interfaces of the Remote Sensing and Signaling Network and the ADME protein network
Regulation of Human Endogenous Metabolites by Drug Transporters and Drug Metabolizing Enzymes: An Analysis of Targeted SNP-Metabolite Associations
Drug transporters and drug-metabolizing enzymes are primarily known for their role in the absorption, distribution, metabolism, and excretion (ADME) of small molecule drugs, but they also play a key role in handling endogenous metabolites. Recent cross-tissue co-expression network analyses have revealed a âRemote Sensing and Signaling Networkâ of multispecific, oligo-specific, and monospecific transporters and enzymes involved in endogenous metabolism. This includes many proteins from families involved in ADME (e.g., SLC22, SLCO, ABCC, CYP, UGT). Focusing on the gutâliverâkidney axis, we identified the endogenous metabolites potentially regulated by this network of ~1000 proteins by associating SNPs in these genes with the circulating levels of thousands of small, polar, bioactive metabolites, including free fatty acids, eicosanoids, bile acids, and other signaling metabolites that act in part via G-protein coupled receptors (GPCRs), nuclear receptors, and kinases. We identified 77 genomic loci associated with 7236 unique metabolites. This included metabolites that were associated with multiple, distinct loci, indicating coordinated regulation between multiple genes (including drug transporters and drug-metabolizing enzymes) of specific metabolites. We analyzed existing pharmacogenomic data and noted SNPs implicated in endogenous metabolite handling (e.g., rs4149056 in SLCO1B1) also affecting drug ADME. The overall results support the existence of close relationships, via interactions with signaling metabolites, between drug transporters and drug-metabolizing enzymes that are part of the Remote Sensing and Signaling Network, and with GPCRs and nuclear receptors. These analyses highlight the potential for drugâmetabolite interactions at the interfaces of the Remote Sensing and Signaling Network and the ADME protein network
Recommended from our members
Regulation of Human Endogenous Metabolites by Drug Transporters and Drug Metabolizing Enzymes: An Analysis of Targeted SNP-Metabolite Associations
Drug transporters and drug-metabolizing enzymes are primarily known for their role in the absorption, distribution, metabolism, and excretion (ADME) of small molecule drugs, but they also play a key role in handling endogenous metabolites. Recent cross-tissue co-expression network analyses have revealed a "Remote Sensing and Signaling Network" of multispecific, oligo-specific, and monospecific transporters and enzymes involved in endogenous metabolism. This includes many proteins from families involved in ADME (e.g., SLC22, SLCO, ABCC, CYP, UGT). Focusing on the gut-liver-kidney axis, we identified the endogenous metabolites potentially regulated by this network of ~1000 proteins by associating SNPs in these genes with the circulating levels of thousands of small, polar, bioactive metabolites, including free fatty acids, eicosanoids, bile acids, and other signaling metabolites that act in part via G-protein coupled receptors (GPCRs), nuclear receptors, and kinases. We identified 77 genomic loci associated with 7236 unique metabolites. This included metabolites that were associated with multiple, distinct loci, indicating coordinated regulation between multiple genes (including drug transporters and drug-metabolizing enzymes) of specific metabolites. We analyzed existing pharmacogenomic data and noted SNPs implicated in endogenous metabolite handling (e.g., rs4149056 in SLCO1B1) also affecting drug ADME. The overall results support the existence of close relationships, via interactions with signaling metabolites, between drug transporters and drug-metabolizing enzymes that are part of the Remote Sensing and Signaling Network, and with GPCRs and nuclear receptors. These analyses highlight the potential for drug-metabolite interactions at the interfaces of the Remote Sensing and Signaling Network and the ADME protein network