Aluminium in Fisch und Fischereierzeugnissen

Recent reports associating aluminium with several skeletal (osteomalacia) and neurological disorders (encephalopathy and Alzheimer’s disease) in humans suggest that exposure to aluminium may pose a hazard to health. This requires the examination of aluminiumcontent in different foodstuffs. Therefore, an analytical method for the determination of aluminium in fish and fishery products, especially in fishery products packaged in aluminium cans, was developed using graphite furnace atomic absorption spectrometry. Fillets of lean and fatty fish showed aluminium levels lower than 1mg/kg wet weight, muscle of crustacean, molluscan and shellfish had apparently higher aluminium levels (up to 20 mg/kg wet weight). The aluminium content in some aluminum-canned herring was much higher than the content found in herring caught in the North Sea. These results indicate that aluminium is taken up by the herring fillets in aluminium cans, presumably through the slight and slow dissolution of aluminium from the can wall, due to some defects in the protective lacquer layer. A comparison of the aluminium levels measured in canned herring with the average aluminium-intake (normally between 3 and 5 mg/day) or with the provisional tolerable daily intake of 1mg/kg body weight per day (WHO 1989) indicated, that the aluminium content of the edible part of aquatic food does not play a significant role. High consumption of fish fillets does not pose any health risk.

Welt-Fischereierträge 1995: 112,9 Mio. Tonnen

Total world fishery production 1995, including aquaculture, of fish, shellfish, frogs and turtles – reached a new record of 112.9 million tones live weight. Marine fishery had a share of 91,9 million tonnes (+ 0.4) and freshwater fishery 21.0 million tonnes (+ 2.0). Not included in these figures are seals, whales, crocodiles and algae. Marine mammals and crocodiles are listed by number of killed individuals, and not given by weight. Algae alone represent a biomass of 7.1 million tonnes, but are not included by the FAO in the nominal „total production of the world“ either. About two thirds of the marine fishery harvest was used for human consumption, one third for industrial purposes – mainly production of fish meal and fish oil.

Developing effective restoration plans to tackle the widespread impairment of coastal swimming and shellfishing waters

Congress established a legal imperative to restore the quality of our surface waters when it enacted the Clean Water Act in 1972. The act requires that existing uses of coastal waters such as swimming and shellfishing be protected and restored. Enforcement of this mandate is frequently measured in terms of the ability to swim and harvest shellfish in tidal creeks, rivers, sounds, bays, and ocean beaches. Public-health agencies carry out comprehensive water-quality sampling programs to check for bacteria contamination in coastal areas where swimming and shellfishing occur. Advisories that restrict swimming and shellfishing are issued when sampling indicates that bacteria concentrations exceed federal health standards. These actions place these coastal waters on the U.S. Environmental Protection Agencies’ (EPA) list of impaired waters, an action that triggers a federal mandate to prepare a Total Maximum Daily Load (TMDL) analysis that should result in management plans that will restore degraded waters to their designated uses. When coastal waters become polluted, most people think that improper sewage treatment is to blame. Water-quality studies conducted over the past several decades have shown that improper sewage treatment is a relatively minor source of this impairment. In states like North Carolina, it is estimated that about 80 percent of the pollution flowing into coastal waters is carried there by contaminated surface runoff. Studies show this runoff is the result of significant hydrologic modifications of the natural coastal landscape. There was virtually no surface runoff occurring when the coastal landscape was natural in places such as North Carolina. Most rainfall soaked into the ground, evaporated, or was used by vegetation. Surface runoff is largely an artificial condition that is created when land uses harden and drain the landscape surfaces. Roofs, parking lots, roads, fields, and even yards all result in dramatic changes in the natural hydrology of these coastal lands, and generate huge amounts of runoff that flow over the land’s surface into nearby waterways. (PDF contains 3 pages)

Watershed monitoring and the TMDL modeling to assess bacterial loading in estuarine environments to improve management

Shellfish bed closures along the North Carolina coast have increased over the years seemingly concurrent with increases in population (Mallin 2000). More and faster flowing storm water has come to mean more bacteria, and fecal indicator bacterial (FIB) standards for shellfish harvesting are often exceeded when no source of contamination is readily apparent (Kator and Rhodes, 1994). Could management reduce bacterial loads if the source of the bacteria where known? Several potentially useful methods for differentiating human versus animal pollution sources have emerged including Ribotyping and Multiple Antibiotic Resistance (MAR) (US EPA, 2005). Total Maximum Daily Load (TMDL) studies on bacterial sources have been conducted for streams in NC mountain and Piedmont areas (U.S. EPA, 1991 and 2005) and are likely to be mandated for coastal waters. TMDL analysis estimates allowable pollutant loads and allocates them to known sources so management actions may be taken to restore water to its intended uses (U.S. EPA, 1991 and 2005). This project sought first to quantify and compare fecal contamination levels for three different types of land use on the coast, and second, to apply MAR and ribotyping techniques and assess their effectiveness for indentifying bacterial sources. Third, results from these studies would be applied to one watershed to develop a case study coastal TMDL. All three watershed study areas are within Carteret County, North Carolina. Jumping Run Creek and Pettiford Creek are within the White Oak River Basin management unit whereas the South River falls within the Neuse River Basin. Jumping Run Creek watershed encompasses approximately 320 ha. Its watershed was a dense, coastal pocosin on sandy, relic dune ridges, but current land uses are primarily medium density residential. Pettiford Creek is in the Croatan National Forest, is 1133 ha. and is basically undeveloped. The third study area is on Open Grounds Farm in the South River watershed. Half of the 630 ha. watershed is under cultivation with most under active water control (flashboard risers). The remaining portion is forested silviculture.(PDF contains 4 pages)

Tympanotonus fuscatus - its potential and abundance in the mangrove swamps of the upper Bonny River, River State

The Shellfish Tympanotonus fuscatus fisheries was studied in the upper Bonny River of River State. Abundance and size distribution were evaluated through collection of the Shellfish from 4 sampling stations along the River System. Shell size differences were observed between the sampling stations. The periwinkles, which were harvested heavily by local women, were smaller. The results do suggest that the population of Tympanotonus fuscatus in the Mangrove swamps of the upper Bonny River Creeks are strongly influenced by the harvesting

Responsible fisheries enhancing poverty alleviation of fishing communities of Lake Kainji

The attributes of responsible fisheries in enhancing Poverty Alleviation of fishing Communities of Lake Kainji were appraised. After impoundment in 1968, the catch per unit effort of fish continued on a downward trend, which suggested a decline in the fish population as a result of improper fishing methods such as the use of small mesh size nets, fish poisoning, destructive fishing gears like beach seine nets. The Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project intervention brought an increase in yields for the lake in 1996. The estimated annual yield was put at 38.244 metric tones in 1996, an increase of 18 % from the yield recorded in 1995 due to improvement in fishing and conservation methods. The result of catch assessment study carried out in 2003 as a follow up to GTZ intervention is presented. This reveals 15 family and 40 species of fish recorded. Which shows that Lake Kainji still has very high diversity and abundance of fish species. The paper suggests ways to encourage fishing communities to adopt new innovation or strategies by the government and non-governmental organization, which will go a long way in alleviation poverty among the fisher folks

Promoting women participation in fish culture enterprises - as a means of poverty alleviation in Nigeria

One major aspect of the poverty status in Nigeria is the high rate of unemployment with the attendant economic in capacity, which in turn is responsible for the persistent problem of malnutrition over the decades. This paper is focused on how women can be empowered for better productivity in fish culture enterprises, seeing that women have been active in different aspects of agricultural production. They also sustain more than half of the developing countries such as Nigeria. Some problems being encountered by would be women fish farmers and suggestions on how women participation in fish and shellfish culture enterprises can be enhanced are proffered. The major ones being those sustainable policies by the Government State ADPs and NGOs are applied to ensure adequate motivation of women for fish culture enterprises

Preparo e administração de medicamentos por sondas em pacientes que recebem nutrição enteral

O objeto de estudo foi o preparo e a administração de medicamentos por cateter pela enfermagem em pacientes que recebem nutrição enteral. O objetivo geral foi investigar o padrão de preparo e administração dos medicamentos por cateter em pacientes que recebem nutrição enteral concomitante. Os objetivos específicos foram apresentar o perfil dos medicamentos preparados e administrados de acordo com a possibilidade de serem administrados por cateter enteral e avaliar o tipo e a freqüência de erros que ocorrem no preparo e administração de medicamentos por cateter. Tratou-se de uma pesquisa com desenho transversal de natureza observacional, sem modelo de intervenção. Foi desenvolvida em um hospital do Rio de Janeiro onde foram observados técnicos de enfermagem preparando e administrando medicamentos por cateter na Unidade de Terapia Intensiva. Foram observadas 350 doses de medicamentos sendo preparados e administrados. Os grupos de medicamentos prevalentes foram os que agem no Sistema Cardiovascular Renal com 164 doses (46,80%), seguido pelos que agem no Sistema Respiratório e Sangue com 12,85% e 12,56% respectivamente. Foram encontrados 19 medicamentos diferentes do primeiro grupo, dois no segundo e cinco no terceiro. As categorias de erro no preparo foram trituração, diluição e misturas. Encontrou-se uma taxa média de 67,71% no preparo de medicamentos. Comprimidos simples foram preparados errados em 72,54% das doses, e todos os comprimidos revestidos e de liberação prolongada foram triturados indevidamente entre sólidos a categoria de erro prevalente foi trituração com 45,47%, preparar misturando medicamentos foi um erro encontrado em quase 40% das doses de medicamentos sólidos. A trituração insuficiente ocorreu em 73,33% das doses de ácido fólico, do cloridrato de amiodarona (58,97%) e bromoprida (50,00%). A mistura com outros medicamentos ocorreu em 66,66% das doses de bromoprida, de besilato de anlodipina (53,33%), bamifilina (43,47%), ácido fólico (40,00%) e ácido acetilsalicílico (33,33%). Os erros na administração foram ausência de pausa e manejo indevido do cateter. A taxa média de erros na administração foi de 32,64%, distribuídas entre 17,14% para pausa e 48,14% para manejo do cateter. A ausência de lavagem do cateter antes foi o erro mais comum e o mais incomum foi não lavar o cateter após a administração. Os medicamentos mais envolvidos em erros na administração foram: cloridrato de amiodarona (n=39), captopril (n=33), cloridrato de hidralazina (n=7), levotiroxina sódica (n=7). Com relação à lavagem dos cateteres antes, ela não ocorreu em 330 doses de medicamentos. O preparo e administração inadequados de medicamentos podem levar à perdas na biodisponibilidade, diminuição do nível sérico e riscos de intoxicações para o paciente. Preparar e administrar medicamentos são procedimentos comuns, porém apresentou altas taxas de erros, o que talvez reflita pouco conhecimento desses profissionais sobre as boas práticas da terapia medicamentosa. Constata-se a necessidade de maior investimento de todos os profissionais envolvidos, médicos, enfermeiros e farmacêuticos nas questões que envolvam a segurança com medicamentos assim como repensar o processo de trabalho da enfermagem.

Kinetic investigations of heterogeneously catalyzed reactions on the Ru(001) and Pt(110)-(1x2) surfaces

The initial probabilities of activated, dissociative chemisorption of methane and ethane on Pt(110)-(1 x 2) have been measured. The surface temperature was varied from 450 to 900 K with the reactant gas temperature constant at 300 K. Under these conditions, we probe the kinetics of dissociation via trapping-mediated (as opposed to 'direct') mechanism. It was found that the probabilities of dissociation of both methane and ethane were strong functions of the surface temperature with an apparent activation energies of 14.4 kcal/mol for methane and 2.8 kcal/mol for ethane, which implys that the methane and ethane molecules have fully accommodated to the surface temperature. Kinetic isotope effects were observed for both reactions, indicating that the C-H bond cleavage was involved in the rate-limiting step. A mechanistic model based on the trapping-mediated mechanism is used to explain the observed kinetic behavior. The activation energies for C-H bond dissociation of the thermally accommodated methane and ethane on the surface extracted from the model are 18.4 and 10.3 kcal/mol, respectively.

The studies of the catalytic decomposition of formic acid on the Ru(001) surface with thermal desorption mass spectrometry following the adsorption of DCOOH and HCOOH on the surface at 130 and 310 K are described. Formic acid (DCOOH) chemisorbs dissociatively on the surface via both the cleavage of its O-H bond to form a formate and a hydrogen adatom, and the cleavage of its C-O bond to form a carbon monoxide, a deuterium adatom and an hydroxyl (OH). The former is the predominant reaction. The rate of desorption of carbon dioxide is a direct measure of the kinetics of decomposition of the surface formate. It is characterized by a kinetic isotope effect, an increasingly narrow FWHM, and an upward shift in peak temperature with Ɵ_T, the coverage of the dissociatively adsorbed formic acid. The FWHM and the peak temperature change from 18 K and 326 K at Ɵ_T = 0.04 to 8 K and 395 K at Ɵ_T = 0.89. The increase in the apparent activation energy of the C-D bond cleavage is largely a result of self-poisoning by the formate, the presence of which on the surface alters the electronic properties of the surface such that the activation energy of the decomposition of formate is increased. The variation of the activation energy for carbon dioxide formation with Ɵ_T accounts for the observed sharp carbon dioxide peak. The coverage of surface formate can be adjusted over a relatively wide range so that the activation energy for C-D bond cleavage in the case of DCOOH can be adjusted to be below, approximately equal to, or well above the activation energy for the recombinative desorption of the deuterium adatoms. Accordingly, the desorption of deuterium was observed to be governed completely by the desorption kinetics of the deuterium adatoms at low Ɵ_T, jointly by the kinetics of deuterium desorption and C-D bond cleavage at intermediate Ɵ_T, and solely by the kinetics of C-D bond cleavage at high Ɵ_T. The overall branching ratio of the formate to carbon dioxide and carbon monoxide is approximately unity, regardless the initial coverage Ɵ_T, even though the activation energy for the production of carbon dioxide varies with Ɵ_T. The desorption of water, which implies C-O bond cleavage of the formate, appears at approximately the same temperature as that of carbon dioxide. These observations suggest that the cleavage of the C-D bond and that of the C-O bond of two surface formates are coupled, possibly via the formation of a short-lived surface complex that is the precursor to to the decomposition.

The measurement of steady-state rate is demonstrated here to be valuable in determining kinetics associated with short-lived, molecularly adsorbed precursor to further reactions on the surface, by determining the kinetic parameters of the molecular precursor of formaldehyde to its dissociation on the Pt(110)-(1 x 2) surface.

Overlayers of nitrogen adatoms on Ru(001) have been characterized both by thermal desorption mass spectrometry and low-energy electron diffraction, as well as chemically via the postadsorption and desorption of ammonia and carbon monoxide.

The nitrogen-adatom overlayer was prepared by decomposing ammonia thermally on the surface at a pressure of 2.8 x 10^(-6) Torr and a temperature of 480 K. The saturated overlayer prepared under these conditions has associated with it a (√247/10 x √247/10)R22.7° LEED pattern, has two peaks in its thermal desorption spectrum, and has a fractional surface coverage of 0.40. Annealing the overlayer to approximately 535 K results in a rather sharp (√3 x √3)R30° LEED pattern with an associated fractional surface coverage of one-third. Annealing the overlayer further to 620 K results in the disappearance of the low-temperature thermal desorption peak and the appearance of a rather fuzzy p(2x2) LEED pattern with an associated fractional surface coverage of approximately one-fourth. In the low coverage limit, the presence of the (√3 x √3)R30° N overlayer alters the surface in such a way that the binding energy of ammonia is increased by 20% relative to the clean surface, whereas that of carbon monoxide is reduced by 15%.

A general methodology for the indirect relative determination of the absolute fractional surface coverages has been developed and was utilized to determine the saturation fractional coverage of hydrogen on Ru(001). Formaldehyde was employed as a bridge to lead us from the known reference point of the saturation fractional coverage of carbon monoxide to unknown reference point of the fractional coverage of hydrogen on Ru(001), which is then used to determine accurately the saturation fractional coverage of hydrogen. We find that ƟSAT/H = 1.02 (±0.05), i.e., the surface stoichiometry is Ru : H = 1 : 1. The relative nature of the method, which cancels systematic errors, together with the utilization of a glass envelope around the mass spectrometer, which reduces spurious contributions in the thermal desorption spectra, results in high accuracy in the determination of absolute fractional coverages.

Quantum Mechanics Studies of Fuel Cell Catalysts and Proton Conducting Ceramics with Validation by Experiment

We carried out quantum mechanics (QM) studies aimed at improving the performance of hydrogen fuel cells. This led to predictions of improved materials, some of which were subsequently validated with experiments by our collaborators.

In part I, the challenge was to find a replacement for the Pt cathode that would lead to improved performance for the Oxygen Reduction Reaction (ORR) while remaining stable under operational conditions and decreasing cost. Our design strategy was to find an alloy with composition Pt3M that would lead to surface segregation such that the top layer would be pure Pt, with the second and subsequent layers richer in M. Under operating conditions we expect the surface to have significant O and/or OH chemisorbed on the surface, and hence we searched for M that would remain segregated under these conditions. Using QM we examined surface segregation for 28 Pt₃M alloys, where M is a transition metal. We found that only Pt₃Os and Pt₃Ir showed significant surface segregation when O and OH are chemisorbed on the catalyst surfaces. This result indicates that Pt₃Os and Pt3Ir favor formation of a Pt-skin surface layer structure that would resist the acidic electrolyte corrosion during fuel cell operation environments. We chose to focus on Os because the phase diagram for Pt-Ir indicated that Pt-Ir could not form a homogeneous alloy at lower temperature. To determine the performance for ORR, we used QM to examine all intermediates, reaction pathways, and reaction barriers involved in the processes for which protons from the anode reactions react with O₂ to form H₂O. These QM calculations used our Poisson-Boltzmann implicit solvation model include the effects of the solvent (water with dielectric constant 78 with pH 7 at 298K). We found that the rate determination step (RDS) was the O_ad hydration reaction (O_ad + H₂O_ad -> OH_ad + OH_ad) in both cases, but that the barrier for pure Pt of 0.50 eV is reduced to 0.48 eV for Pt₃Os, which at 80 degrees C would increase the rate by 218%. We collaborated with the Pu-Wei Wu’s group to carry out experiments, where we found that the dealloying process-treated Pt2Os catalyst showed two-fold higher activity at 25 degrees C than pure Pt and that the alloy had 272% improved stability, validating our theoretical predictions.

We also carried out similar QM studies followed by experimental validation for the Os/Pt core-shell catalyst fabricated by the underpotential deposition (UPD) method. The QM results indicated that the RDS for ORR is a compromise between the OOH formation step (0.37 eV for Pt, 0.23 eV for Pt_2ML/Os core-shell) and H₂O formation steps (0.32 eV for Pt, 0.22 eV for Pt_2ML/Os core-shell). We found that Pt_2ML/Os has the highest activity (compared to pure Pt and to the Pt₃Os alloy) because the 0.37 eV barrier decreases to 0.23 eV. To understand what aspects of the core shell structure lead to this improved performance, we considered the effect on ORR of compressing the alloy slab to the dimensions of pure Pt. However this had little effect, with the same RDS barrier 0.37 eV. This shows that the ligand effect (the electronic structure modification resulting from the Os substrate) plays a more important role than the strain effect, and is responsible for the improved activity of the core- shell catalyst. Experimental materials characterization proves the core-shell feature of our catalyst. The electrochemical experiment for Pt_2ML/Os/C showed 3.5 to 5 times better ORR activity at 0.9V (vs. NHE) in 0.1M HClO₄ solution at 25 degrees C as compared to those of commercially available Pt/C. The excellent correlation between experimental half potential and the OH binding energies and RDS barriers validate the feasibility of predicting catalyst activity using QM calculation and a simple Langmuir–Hinshelwood model.

In part II, we used QM calculations to study methane stream reforming on a Ni-alloy catalyst surfaces for solid oxide fuel cell (SOFC) application. SOFC has wide fuel adaptability but the coking and sulfur poisoning will reduce its stability. Experimental results suggested that the Ni4Fe alloy improves both its activity and stability compared to pure Ni. To understand the atomistic origin of this, we carried out QM calculations on surface segregation and found that the most stable configuration for Ni₄Fe has a Fe atom distribution of (0%, 50%, 25%, 25%, 0%) starting at the bottom layer. We calculated that the binding of C atoms on the Ni4Fe surface is 142.9 Kcal/mol, which is about 10 Kcal/mol weaker compared to the pure Ni surface. This weaker C binding energy is expected to make coke formation less favorable, explaining why Ni₄Fe has better coking resistance. This result confirms the experimental observation. The reaction energy barriers for CHx decomposition and C binding on various alloy surface, Ni₄X (X=Fe, Co, Mn, and Mo), showed Ni₄Fe, Ni₄Co, and Fe₄Mn all have better coking resistance than pure Ni, but that only Ni₄Fe and Fe₄Mn have (slightly) improved activity compared to pure Ni.

In part III, we used QM to examine the proton transport in doped perovskite-ceramics. Here we used a 2x2x2 supercell of perovskite with composition Ba₈X₇M₁(OH)₁O₂₃ where X=Ce or Zr and M=Y, Gd, or Dy. Thus in each case a 4⁺ X is replace by a 3⁺ M plus a proton on one O. Here we predicted the barriers for proton diffusion allowing both includes intra-octahedron and inter-octahedra proton transfer. Without any restriction, we only observed the inter-octahedra proton transfer with similar energy barrier as previous computational work but 0.2 eV higher than experimental result for Y doped zirconate. For one restriction in our calculations is that the O_donor-O_acceptor atoms were kept at fixed distances, we found that the barrier difference between cerates/zirconates with various dopants are only 0.02~0.03 eV. To fully address performance one would need to examine proton transfer at grain boundaries, which will require larger scale ReaxFF reactive dynamics for systems with millions of atoms. The QM calculations used here will be used to train the ReaxFF force field.

Signatures of Topological Superconductors

Topological superconductors are particularly interesting in light of the active ongoing experimental efforts for realizing exotic physics such as Majorana zero modes. These systems have excitations with non-Abelian exchange statistics, which provides a path towards topological quantum information processing. Intrinsic topological superconductors are quite rare in nature. However, one can engineer topological superconductivity by inducing effective p-wave pairing in materials which can be grown in the laboratory. One possibility is to induce the proximity effect in topological insulators; another is to use hybrid structures of superconductors and semiconductors.

The proposal of interfacing s-wave superconductors with quantum spin Hall systems provides a promising route to engineered topological superconductivity. Given the exciting recent progress on the fabrication side, identifying experiments that definitively expose the topological superconducting phase (and clearly distinguish it from a trivial state) raises an increasingly important problem. With this goal in mind, we proposed a detection scheme to get an unambiguous signature of topological superconductivity, even in the presence of ordinarily detrimental effects such as thermal fluctuations and quasiparticle poisoning. We considered a Josephson junction built on top of a quantum spin Hall material. This system allows the proximity effect to turn edge states in effective topological superconductors. Such a setup is promising because experimentalists have demonstrated that supercurrents indeed flow through quantum spin Hall edges. To demonstrate the topological nature of the superconducting quantum spin Hall edges, theorists have proposed examining the periodicity of Josephson currents respect to the phase across a Josephson junction. The periodicity of tunneling currents of ground states in a topological superconductor Josephson junction is double that of a conventional Josephson junction. In practice, this modification of periodicity is extremely difficult to observe because noise sources, such as quasiparticle poisoning, wash out the signature of topological superconductors. For this reason, We propose a new, relatively simple DC measurement that can compellingly reveal topological superconductivity in such quantum spin Hall/superconductor heterostructures. More specifically, We develop a general framework for capturing the junction's current-voltage characteristics as a function of applied magnetic flux. Our analysis reveals sharp signatures of topological superconductivity in the field-dependent critical current. These signatures include the presence of multiple critical currents and a non-vanishing critical current for all magnetic field strengths as a reliable identification scheme for topological superconductivity.

This system becomes more interesting as interactions between electrons are involved. By modeling edge states as a Luttinger liquid, we find conductance provides universal signatures to distinguish between normal and topological superconductors. More specifically, we use renormalization group methods to extract universal transport characteristics of superconductor/quantum spin Hall heterostructures where the native edge states serve as a lead. Interestingly, arbitrarily weak interactions induce qualitative changes in the behavior relative to the free-fermion limit, leading to a sharp dichotomy in conductance for the trivial (narrow superconductor) and topological (wide superconductor) cases. Furthermore, we find that strong interactions can in principle induce parafermion excitations at a superconductor/quantum spin Hall junction.

As we identify the existence of topological superconductor, we can take a step further. One can use topological superconductor for realizing Majorana modes by breaking time reversal symmetry. An advantage of 2D topological insulator is that networks required for braiding Majoranas along the edge channels can be obtained by adjoining 2D topological insulator to form corner junctions. Physically cutting quantum wells for this purpose, however, presents technical challenges. For this reason, I propose a more accessible means of forming networks that rely on dynamically manipulating the location of edge states inside of a single 2D topological insulator sheet. In particular, I show that edge states can effectively be dragged into the system's interior by gating a region near the edge into a metallic regime and then removing the resulting gapless carriers via proximity-induced superconductivity. This method allows one to construct rather general quasi-1D networks along which Majorana modes can be exchanged by electrostatic means.

Apart from 2D topological insulators, Majorana fermions can also be generated in other more accessible materials such as semiconductors. Following up on a suggestion by experimentalist Charlie Marcus, I proposed a novel geometry to create Majorana fermions by placing a 2D electron gas in proximity to an interdigitated superconductor-ferromagnet structure. This architecture evades several manufacturing challenges by allowing single-side fabrication and widening the class of 2D electron gas that may be used, such as the surface states of bulk semiconductors. Furthermore, it naturally allows one to trap and manipulate Majorana fermions through the application of currents. Thus, this structure may lead to the development of a circuit that enables fully electrical manipulation of topologically-protected quantum memory. To reveal these exotic Majorana zero modes, I also proposed an interference scheme to detect Majorana fermions that is broadly applicable to any 2D topological superconductor platform.

Production of positive controls for calcivirus-specific PCR using recombinant baculiovirus technology

Recent advances in our knowledge of the genetic structure of human caliciviruses (HuCVs) and small round-structured viruses (SRSVs) have led to the development of polymerase chain reaction (PCR)-based molecular tests specific for these viruses. These methods have been developed to detect a number of human pathogenic viruses in environmental samples including water, sewage and shellfish. HuCVs and SRSVs are not culturable, and no animal model is currently available. Therefore there is no convenient method of preparing viruses for study or for reagent production. One problem facing those attempting to use PCR-based methods for the detection of HuCVs and SRSVs is the lack of a suitable positive control substrate. This is particularly important when screening complex samples in which the levels of inhibitors present may significantly interfere with amplificiation. Regions within the RNA polymerase regions of two genetically distinct human caliciviruses have been amplified and used to produce recombinant baculoviruses which express RNA corresponding to the calicivirus polymerase. This RNA is being investigated as a positive control substrate for PCR testing, using current diagnostic primer sets. Recombinant baculovirus technology will enable efficient and cost-effective production of large quantities of positive control RNA with a specific known genotype. We consider the development of these systems as essential for successful screening and monitoring applications.

SIHSUS como fonte para o estudo de morbi-mortalidade por medicamentos no Estado do Rio de Janeiro

A despeito de suas limitações, os dados do SIHSUS são os mais sistemáticos e abrangentes sobre as Reações Adversas e Intoxicações a medicamentos que provocam hospitalização. Eles demonstram a importância das ações de educação e investigação de casos do Programa Nacional de Farmacovigilância para possibilitar o diagnóstico mais acurado e superação do quadro atual de ocorrência desses agravos, além da possibilidade de o SIH/SUS ser utilizado sistematicamente como fonte de dados na detecção e análise dos problemas relacionados a medicamentos. No período de 1999 a 2007, foram emitidas 6.670.609 AIH (tipo 1), entre as quais 3.611 foram classificadas como internações devidas a RAM e 4.675 como Intoxicações, correspondendo, respectivamente, às taxas médias de 5,41 casos por 104 AIH e 7,2 casos por 104 AIH. Ocorreram 137 óbitos (3,79% das AIH) por RAM e 207 (4,43% das AIH) por Intoxicações na população internada. Tanto as RAM como as Intoxicações tiveram menor chance de levar ao óbito quando comparados às outras causas. Uma característica da distribuição dos RAM foi concentrar 62% das AIH nas faixas etárias de 20 a 59 anos de idade (grupo adulto). Nas Intoxicações merece destaque a elevada proporção de AIH na faixa etária de 0-4 anos (14,29%). As AIH registradas com causas básicas relacionados a RAM foram principalmente de pacientes do sexo masculino, já as Intoxicações foram principalmente de pacientes do sexo feminino. Em ambos tipos de agravos estes pacientes foram internados em hospitais que não faziam parte da Rede de Hospitais Sentinelas do Programa Nacional de Farmacovigilância. No entanto, a probabilidade destes hospitais registrarem as AIH com códigos CID-10 referentes às RAM é maior, o que ocorre provavelmente por estarem mais capacitados em diagnosticar este tipo de agravo. Porém este fato não foi observado para as Intoxicações. Os fármacos que causaram os agravos estudados são psicoativos. Este estudo apresentou algumas evidências sobre a distribuição da morbi-mortalidade provocada por medicamentos entre pacientes internados em hospitais conveniados ao SUS no período de 1999-2007, baseadas nas informações das AIH, que podem ser úteis ao Programa de Farmacovigilância no Estado do Rio de Janeiro.

Vulnerabilidade socioambiental dos manguezais de Garapuá, Cairu/BA frente à inserção da indústria petroleira.

Manguezais são ecossistemas marinhos costeiros que ocorrem nas regiões tropicais e subtropicais do globo. A associação desses ambientes a formações recifais é restrita, particularmente no Brasil, onde se destaca a ilha de Tinharé, na costa sul do estado da Bahia, não só pela ocorrência desse sistema manguezal-recifes, mas também pelo desenvolvimento estrutural da floresta e pela atividade produtiva de mariscagem exercida pela população do povoado de Garapuá. Apesar da proximidade de Morro de São Paulo, atrator turístico internacional, este povoado experimentava certo isolamento socioeconômico até a chegada da indústria do petróleo que, em função de suas potencialidades e riscos, tensionou a vida da comunidade local. Este estudo tem por objetivo analisar a vulnerabilidade socioambiental dos manguezais adjacentes à Garapuá, Cairu-BA, frente a inserção da indústria petrolífera na região, a partir da caracterização estrutural das florestas de mangue e da caracterização social do povoado de Garapuá e, particularmente, das marisqueiras usuárias deste ecossistema. As abordagens metodológicas utilizadas podem ser classificadas como pesquisas quantitativas, empregadas no levantamento fitossociológico, e qualitativas, utilizadas a partir de observações de campo e entrevistas, além de levantamentos bibliográficos, para elaboração das análises sociais. Os resultados indicam florestas de mangue de porte variável, em bom estado de conservação, com altura média das dez árvores mais altas entre 2,40,2 metros (estação 7) e 22,71,1 metros (estação 29), geralmente dominadas por Rhizophora mangle (38 das 52 estações de amostragem). A partir da caracterização estrutural foi realizado teste estatístico de agrupamento que, aliado a aspectos da arquitetura das árvores, permitiu a classificação das florestas em 12 Tipos Estruturais. As análises relativas à vulnerabilidade ambiental fundamentaram-se nos aspectos de sensibilidade e na posição fisiográfica ocupada por cada Tipo de floresta e identificaram níveis distintos de vulnerabilidade a derramamentos de óleo. Com relação aos aspectos sociais, as informações sobre os sistemas socioeconômicos e culturais relacionados à saúde, à educação, às práticas produtivas e à geração de renda, ao transporte, à religião e à organização social, como um todo, evidenciaram vulnerabilidades frente à inserção da indústria do petróleo, apontando as marisqueiras como o segmento mais suscetível a vivenciar os riscos e os impactos desse empreendimento no local. A inserção da indústria do petróleo neste contexto socioambiental representa aumento de riscos e, consequentemente, de vulnerabilidade socioambiental, na medida em que o diálogo estabelecido entre empreendedor e população se apresenta de forma assimétrica, dificultando a participação da população local, sobretudo dos mais excluídos que, nesse caso, são representados pelos usuários dos manguezais.

Eventos de vida produtores de estresse e acidentes de trabalho: Estudo Pró-Saúde, Rio de Janeiro - Brasil

A proposta desta tese consiste em um recorte de uma abordagem mais ampla da determinação dos acidentes de trabalho, e tem como objetivo geral investigar o perfil de acidentes de trabalho que acometem funcionários técnico-administrativos do quadro efetivo de uma universidade do Rio de Janeiro. Para o alcance do objetivo, esta tese está estruturada em dois artigos, e como tal pretende explorar o perfil sócio-demográfico e ocupacional de funcionários públicos na ocorrência de acidentes de trabalho (Artigo 1); e investigar a associação entre os eventos de vida produtores de estresse (EVPE) e a ocorrência de acidentes de trabalho (Artigo 2). Dados seccionais da fase 2 de um estudo de natureza prospectiva (Estudo Pró-Saúde) foram coletados entre 3572 funcionários. A história de acidentes de trabalho foi captada por meio de perguntas dicotômicas (sim vs. não) para cada um dos seguintes tipos de acidentes: perfuração com agulha; perfuração com outro objeto; corte; queimadura; choque elétrico; contusão ou distensão muscular; fratura, entorse ou luxação; e envenenamento ou intoxicação. O período de referência para aferição tanto dos EVPE quanto da ocorrência de acidente de trabalho correspondeu aos 12 meses anteriores a aplicação de questionário autopreenchível. No artigo 1 utilizou-se a técnica de análise de correspondência múltipla para delimitar agrupamentos de funcionários quanto ao perfil sócio-demográfico e ocupacional associado à ocorrência de acidente de trabalho, de acordo com as seguintes Característica : sexo, idade, escolaridade, renda per capita, ocupação, setor e local de trabalho. No artigo 2, a associação entre EVPE e acidentes de trabalho foi avaliada através de análise multivariada por meio de modelo lineares generalizados (logpoisson), sendo os resultados expressos através de razões de prevalência (RP) ajustadas e seus respectivos intervalos de 95% de confiança (IC95%). A prevalência total de acidentes no período de 12 meses foi de 25,6%. Dos tipos de acidentes referidos, o mais frequente foi a contusão ou fratura, com cerca de (10,2%) de relatos. Em seguida, aparecem as perfurações com agulha (6,5%). Os resultados da análise de correspondência revelam três grupos, destacando-se aquele formado pelos que sofreram perfuração com agulha com um perfil que abrange os auxiliares de enfermagem, trabalham no Hospital Universitário e setores adjacentes, especificamente em setores de terapia intensiva, emergência, cirurgia geral, clinica geral e ambulatório. Em relação à associação com EVPE, ter sido testemunha de agressão foi o evento mais fortemente associado com acidentes de trabalho (RP= 1,98, IC95%= 1,67; 2,34). Este estudo trouxe informações acerca da importância das características sócio-demográficas e de aspectos psicossociais na ocorrência dos acidentes de trabalho que podem ser úteis na elaboração de medidas para a prevenção desse importante problema de saúde pública.