Structure of the N intermediate of bacteriorhodopsin revealed by x-ray diffraction.

X-ray diffraction experiments revealed the structure of the N photointermediate of bacteriorhodopsin. Since the retinal Schiff base is reprotonated from Asp-96 during the M to N transition in the photocycle, and Asp-96 is reprotonated during the lifetime of the N intermediate, or immediately after, N is a key intermediate for understanding the light-driven proton pump. The N intermediate accumulates in large amounts during continuous illumination of the F171C mutant at pH 7 and 5 degrees Celsius. Small but significant changes of the structure were detected in the x-ray diffraction profile under these conditions. The changes were reversible and reproducible. The difference Fourier map indicates that the major change occurs near helix F. The observed diffraction changes between N and the original state were essentially identical to the diffraction changes reported for the M intermediate of the D96N mutant of bacteriorhodopsin. Thus, we find that the protein conformations of the M and N intermediates of the photocycle are essentially the same, in spite of the fact that in M the Schiff base is unprotonated and in N it is protonated. The observed structural change near helix F will increase access of the Schiff base and Asp-96 to the cytoplasmic surface and facilitate the proton transfer events that begin with the decay of the M state.

Evidence of Intracrystalline Mesostructured Porosity in Zeolites by Advanced Gas Sorption, Electron Tomography and Rotation Electron Diffraction

The small size of micropores (typically <1 nm) in zeolites causes slow diffusion of reactant and product molecules in and out of the pores and negatively impacts the product selectivity of zeolite based catalysts, for example, fluid catalytic cracking (FCC) catalysts. Size-tailored mesoporosity was introduced into commercial zeolite Y crystals by a simple surfactant-templating post-synthetic mesostructuring process. The resulting mesoporous zeolite Y showed significantly improved product selectivity in both laboratory testing and refinery trials. Advanced characterization techniques such as electron tomography, three-dimensional rotation electron diffraction, and high resolution gas adsorption coupled with hysteresis scanning and density functional theory, unambiguously revealed the intracystalline nature and connectivity of the introduced mesopores. They can be considered as molecular highways that help reactant and product molecules diffuse quickly to and away from the catalytically active sites within the zeolite crystals and, thus, shift the selectivity to favor the production of more of the valuable liquid fuels at reduced yields of coke and unconverted feed.

A função respiratória dos doentes adultos com fibrose quística, em repouso e no esforço

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Prevenção de proliferação vítreo-retiniana após cirurgia a descolamento de retina regmatogéneo primário

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

A multimodal tablet-based interface for designing and reviewing 3D engineering models

The ability to view and interact with 3D models has been happening for a long time. However, vision-based 3D modeling has only seen limited success in applications, as it faces many technical challenges. Hand-held mobile devices have changed the way we interact with virtual reality environments. Their high mobility and technical features, such as inertial sensors, cameras and fast processors, are especially attractive for advancing the state of the art in virtual reality systems. Also, their ubiquity and fast Internet connection open a path to distributed and collaborative development. However, such path has not been fully explored in many domains. VR systems for real world engineering contexts are still difficult to use, especially when geographically dispersed engineering teams need to collaboratively visualize and review 3D CAD models. Another challenge is the ability to rendering these environments at the required interactive rates and with high fidelity. In this document it is presented a virtual reality system mobile for visualization, navigation and reviewing large scale 3D CAD models, held under the CEDAR (Collaborative Engineering Design and Review) project. It’s focused on interaction using different navigation modes. The system uses the mobile device's inertial sensors and camera to allow users to navigate through large scale models. IT professionals, architects, civil engineers and oil industry experts were involved in a qualitative assessment of the CEDAR system, in the form of direct user interaction with the prototypes and audio-recorded interviews about the prototypes. The lessons learned are valuable and are presented on this document. Subsequently it was prepared a quantitative study on the different navigation modes to analyze the best mode to use it in a given situation.

Planktic foraminiferal assemblages in sediments of four ODP Leg 198 holes

A pulse of intense carbonate dissolution occurred during the early late Paleocene at 58.4 Ma. A prominent 5 to 25 cm-thick dark brown clay-rich calcareous nannofossil ooze was found on Shatsky Rise at Sites 1209, 1210, 1211, and 1212 during Ocean Drilling Program Leg 198. The layer corresponds to the lower part of planktonic foraminiferal Zone P4 and coincides with the evolutionary first occurrence of the nannolith Heliolithus kleinpellii, an important component of late Paleocene assemblages and a marker for the base of Zone CP5. The clay-rich layer contains common crystals of phillipsite, fish teeth, and phosphatic micronodules and corresponds to a prominent peak in magnetic susceptibility that probably reflects these high amounts of detrital and authigenic materials. Detailed quantitative analysis of planktonic foraminiferal assemblages across the clay-rich nannofossil ooze layer shows that fundamental changes in faunal composition occurred before, during, and after deposition of the clay-rich ooze. Planktonic foraminifers in the clay-rich layer are characterized by a low-diversity, largely dissolved assemblage dominated by representatives of the genus Igorina (mainly Igorina tadjikistanensis and Igorina pusilla). Conversely, Igorina albeari, morozovellids, acarininids, globanomalinids, subbotinids, and chiloguembelinids are common below the clay-rich layer, almost disappear within it, and reappear in low abundances above the clay-rich layer. These changes in faunal compositions are likely a response to a change in carbonate saturation that caused increased dissolution on the seafloor owing to the shoaling of the lysocline and the carbonate compensation depth.

Late Aptian and Cenomanian-Turonian plaktonic foraminifera from DSDP Site 89-585

Planktonic foraminifers from the late Aptian and the Cenomanian-Turonian of Site 585, East Mariana Basin, provide new age data for western Pacific geologic events. The Aptian assemblage dates the volcaniclastic sequence from the bottom of Site 585 and includes several species newly reported from the Pacific Ocean. The Cenomanian-Turonian assemblage constrains the organic-carbon-rich anoxic strata recorded at Site 585 to the Cenomanian-Turonian oceanic anoxic event. Sporadic occurrences of mostly rare, poorly preserved planktonic foraminifers record pulses of sedimentation during the Aptian-Albian, Cenomanian-Turonian, Coniacian-Santonian, and Campanian-Maestrichtian that transported and reworked the pelagic sediments downslope to abyssal depositional environments.

Bulletin van het Koloniaal museum te Haarlem.

"De mededeelingen, die vóór 1892 van het Koloniaal museum zijn uitgegaan, komen alle voor in het Tijdschrift van nijverheid. De verkorte inhoud der jaarverslagen en kleine berichten van het museum worden bij voortduring gepubliceerd in datzelfde maandblad, alsmede in het weekblad De Indische Mercuur."-no. 52, p. 182, foot-note.

Ciel et terre.

Title from cover.

Coroners' handbook on the functions and operations of the Office of Coroner /

"VR 940."

The religion of the Teutons /

Bibliography: p. 417-463.

Revue de philosophie : paraissant tous les deux mois.

Description based on: 31e année, no. 1 (janv./févr. 1931).

Bulletin van het Koloniaal museum te Haarlem

"De mededeelingen, die vöör 1892 van het Koloniaal museum zijn uitgegaan, komen alle voor in het Tijdschrift van nijverheid. De verkorte inhoud der jaarverslagen en kleine berichten van het museum worden bij voortduring gepubliceerd in datzelfde maandblad, alsmede in het weekblad De Indische Mercuur."

Vocational Rehabilitation and Education; Quarterly Information Bulletin

Also Cited as: Vr & E

Begripliga webbtexter : En undersökning av begripligheten i Sollentuna kommuns webbtexter

I denna uppsats analyserar jag några av texterna på Sollentuna kommuns webbplats. Syftet är att undersöka begripligheten i texterna. Jag har låtit en fokusgrupp läsa och diskutera hur de upplever fyra webbtexter. Utifrån gruppens synpunkter har jag gjort en textanalys. Analysen bygger på den systemisk-funktionella lingvistikens tre metafunktioner: den ideationella, den interpersonella och den textuella. Jag har kopplat metafunktionerna till det pragmatiska synsättet, som menar att en begriplig text leder till att mottagarnas läsmål uppfylls, till exempel att mottagarna med hjälp av texten kan utföa handlingar av olika slag. Undersökningens resultat visar att alla fyra webbtexterna innehåller drag som kan försämra begripligheten. De brister som var lättast att koppla till direkta begriplighetsproblem hos fokusgruppen låg på det ideationella planet, som huvudsakligen avser textens innehåll. Framför allt gällde det avsaknad av viktig information men också att huvudämnet inte framgick tillräckligt tydligt. Brister på det textuella planet, som främst avser den språkliga formen, var något svårare att knyta till direkta begriplighetsproblem. I ett par fall gjorde dock texternas komplexa och abstrakta form att fokusgruppen blev osäker på innehållet. Brister på det interpersonella planet, som avser relationen mellan sändaren och mottagaren i texten, var svårast att koppla till fokusgruppens förståelse. Det gällde avsaknad av du-tilltal och direkta uppmaningar.