Pacific Northwest National Laboratory

About: Pacific Northwest National Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Catalysis & Aerosol. The organization has 11581 authors who have published 27934 publications receiving 1120489 citations. The organization is also known as: PNL & PNNL.

Solvent-induced conformational changes of polypeptides probed by electrospray-ionization mass spectrometry.

Abstract: Electrospray-ionization (ESI) mass spectrometry is used to monitor higher order structural changes of polypeptides induced by alteration of the pH or organic solvent composition in the protein solution environment. A bimodal charge-state distribution is observed in the ESI mass spectrum of ubiquitin (relative molecular mass 8565) in solutions containing small amounts (less than 20%) of organic solvents. The distribution of peaks at high m/z (low-charge state) is found to represent the protein in its native, globular state; the higher-charge-state distribution is characteristic for a more extended conformation. Addition of methanol denaturant in excess of 40% v/v is needed to eliminate the low-charge-state distribution completely. Lesser amounts of acetonitrile, acetone, or isopropanol (approximately 20%) are required to denature the ubiquitin protein. Other proteins showing conformational effects in their ESI mass spectra are also illustrated. While the ESI spectra are related to solution phase structure, ESI-tandem mass spectrometry of multiply charged molecular ions of different conformation is suggested as a probe of gas-phase protein three-dimensional structure.

Direct kinetic correlation of carriers and ferromagnetism in Co2+: ZnO.

Abstract: In only a few cases have the key factors controlling long-range magnetic ordering in diluted magnetic semiconductors (DMSs) been unambiguously identified. In Ga1� xMnxAs, the identification and variation of critical experimental parameters has culminated in a testable microscopic model describing hole-mediated magnetic ordering in this and several related manganese-doped III-V semiconductors [1]. The recent discovery of high-Curietemperature (TC) ferromagnetism in doped oxide semiconductors has stimulated intense experimental and theoretical interest in these materials [2]. In contrast with Ga1� xMnxAs, a clear consensus has not yet been reached about the relationship between carriers (bound or free) and ferromagnetism in these doped oxides. Only through identification and systematic variation of key compositional parameters will a significant advance in the understanding of high-TC ferromagnetism in doped oxides be realized. In this Letter, we demonstrate that the native shallow donor interstitial zinc (Zni) is capable of activating high-TC ferromagnetism in Co 2� -doped ZnO (Co 2� : ZnO). The Zni concentration in an oriented epitaxial thin film of Co 2� : ZnO was systematically varied by controlled oxidative removal of these shallow donors at elevated temperatures. A direct correlation between the 300 K ferromagnetic saturation moment (MS) and the concentration of Zni was observed. The experimental activation barriers clearly identify the diffusion of Zni as the rate-determining process in the oxidative quenching of ferromagnetism in Co 2� : ZnO. These results provide conclusive evidence that the high-TC ferromagnetism in Co 2� : ZnO is mediated by

Porous Media : Applications in Biological Systems and Biotechnology

Abstract: A General Set of Bioheat Equations Based on the Volume Averaging Theory, Akira Nakayama, Fujio Kuwahara, and Wei Liu Introduction Volume Averaging Procedure Governing Equation for Blood Flow Two-Energy Equation Model for Blood Flow and Tissue Three-Energy Equation Model for Countercurrent Heat Transfer in a Circulatory System Effect of Spatial Distribution of Perfusion Bleed-Off Rate on Total Countercurrent Heat Transfer Application of Bioheat Equation to Cryoablation Therapy Conclusions Nomenclature Mathematical Models of Mass Transfer in Tissue for Molecular Medicine with Reversible Electroporation, Yair Granot and Boris Rubinsky Introduction Fundamental Aspects of Reversible Electroporation Mathematical Models of Ion Transport during Electroporation Electrical Impedance Tomography of In Vivo Electroporation Mass Transfer in Tissue with Reversible Electroporation Studies on Molecular Medicine with Drug Delivery in Tissue by Electroporation Future Research Needs in Mathematical Modeling of the Field of Electroporation Hydrodynamics in Porous Media with Applications to Tissue Engineering, T. Lemaire, J. Pierre, B. David, and C. Oddou Nomenclature Introduction Cell and Tissue Engineering: Physicochemical Determinants of the Development Bioreactors and Implants Theoretical Models of Active Porous Media Conclusion Biomedical Implications of the Porosity of Microbial Biofilms, H. Ben-Yoav, N. Cohen-Hadar, and Amihay Freeman Introduction The Life Cycle of Biofilms Infectious Microbial Biofilms-Structural and Biological Characteristics Infectious Microbial Biofilms-Treatment Modalities and Resistance Concluding Remarks Influence of Biofilms on Porous Media Hydrodynamics, Robin Gerlach and Alfred B. Cunningham Introduction and Overview An Introduction to Biofilms Experimental Systems and Techniques for the Investigation of Biofilms in Porous Media Biofilms in Porous Media and Their Effect on Hydrodynamics A Few Notes on Modeling Porous Media Biofilms in Nature and Technology Conclusions and Outlook Using Porous Media Theory to Determine the Coil Volume Needed to Arrest Flow in Brain Aneurysms, Khalil M. Khanafer and Ramon Berguer Nomenclature Introduction Physics of Cerebral Aneurysms Background Mathematical Formulations Construction of Brain Aneurysm Meshes from CT Scans Results and Discussion Minimum Packing Density of the Endovascular Coil Future Work Conclusions Lagrangian Particle Methods for Biological Systems, Alexandre M. Tartakovsky, Zhijie Xu, and Paul Meakin Introduction DPDs for Biological Applications SPHs Model for Biofilm Growth An SPH Model for Mineral Precipitation Hybrid Models for Diffusion-Reaction Systems Summary Passive Mass Transport Processes in Cellular Membranes and Their Biophysical Implications, Armin Kargol and Marian Kargol Introduction Thermodynamic KK Equations Porous Membranes Mechanistic Equations of Membrane Transport Water Exchange between Aquatic Plants and the Environment Passive Transport through Cell Membranes of Human Erythrocytes Comparison of Transport Formalisms: KK, ME, and 2P Skin Electroporation: Modeling Perspectives, S.M. Becker and A.V. Kuznetsov Introduction Transdermal Drug Delivery The Skin as a Composite Stratum Corneum and the Lipid Barrier Nondestructive Transport Modeling: The SC as a Porous Medium Skin Electroporation Skin Electroporation Models (nonthermal) Thermodynamic Approach Conclusions Application of Porous Media Theories in Marine Biological Modeling, Arzhang Khalili, Bo Liu, Khodayar Javadi, Mohammad R. Morad, Maciej Matyka, Roman Stocker, and Zbigniew Koza Introduction Mathematical Description of the Model Application of Porous Media in Marine Microbiology Future Perspectives The Transport of Insulin-Like Growth Factor through Cartilage, Lihai Zhang, Bruce S. Gardiner, David W. Smith, Peter Pivonka, and Alan J. Grodzinsky Overview Basic Solute Transport Model in a Deforming Articular Cartilage Basic Solute Transport Model in Cyclically Loaded Cartilage Model Geometry for Radial Solute Transport in Cartilage under Unconfined Cyclic Compression The Effect of Cyclic Loading and IGF-I Binding on IGF-I Transport in Cartilage Interaction between IGF-I and Its IGFBPs Results and Discussion IGF Transport with Competitive Binding in a Deforming Articular Cartilage Model Development for a Competitor Growth Factor An Integrated Model of IGF-I and Mechanical-Loading-Mediated Biosynthesis in a Deformed Articular Cartilage Biosynthesis Model Construction Biosynthesis Model Validation and Predictions Summary Biotechnological and Biomedical Applications of Magnetically Stabilized and Fluidized Beds, Teresa Castelo-Grande, Paulo A. Augusto, Angel M. Estevez, Jesus Ma. Rodriguez, Audelino Alvaro, and Domingos Barbosa Introduction Historical Overview of Magnetically Stabilized and Fluidized Beds MSBs and MFBs General Supporting Theory Main Biotechnological and Biomedical Applications Conclusion and Future Perspectives In Situ Characterizations of Porous Media for Applications in Biofuel Cells: Issues and Challenges, Bor Yann Liaw Introduction Biofuel Cell Applications Desirable Properties and Functionalities Needs for In Situ Characterization: Issues and Challenges Applicable In Situ Techniques Future Directions Spatial Pattern Formation of Motile Microorganisms: From Gravitactic Bioconvection to Protozoan Culture Dynamics, Tri Nguyen-Quang, The Hung Nguyen, and Frederic Guichard Description and Literature Review of Bioconvection Onset and Evolution of Gravitactic Bioconvection: Linear Stability Analysis and Numerical Simulation Experimental Study of the Pattern Formation in a Suspension of Gravitactic Microorganisms Summary and Perspectives of Future Research Appendix: Boussinesq Approximation for the Microorganism Suspension Nomenclature References appear at the end of each chapter.

Effects of Crystallinity on Dilute Acid Hydrolysis of Cellulose by Cellulose Ball-Milling Study

Abstract: The dilute acid (0.05 M H2SO4) hydrolysis at 175 °C of samples comprised of varying fractions of crystalline (α-form) and amorphous cellulose was studied. The amorphous content, based on XRD and CP/MAS NMR, and the product (glucose) yield, based on HPLC, increased by as much as a factor of 3 upon ball milling. These results are interpreted in terms of a model involving mechanical disruption of crystallinity by breaking hydrogen bonds in α-cellulose, opening up the structure, and making more β-1,4 glycosidic bonds readily accessible to the dilute acid. However, in parallel with hydrolysis to form liquid-phase products, there are reactions of amorphous cellulose that form solid degradation products.