Use of Stress Analysis Methods to Evaluate the Biomechanics of Oral Rehabilitation With Implants

Because the biomechanical behavior of dental implants is different from that of natural tooth, clinical problems may occur. The mechanism of stress distribution and load transfer to the implant/bone interface is a critical issue affecting the success rate of implants. Therefore, the aim of this study was to conduct a brief literature review of the available stress analysis methods to study implant-supported prosthesis loading and to discuss their contributions in the biomechanical evaluation of oral rehabilitation with implants. Several studies have used experimental, analytical, and computational models by means of finite element models (FEM), photoelasticity, strain gauges and associations of these methods to evaluate the biomechanical behavior of dental implants. The FEM has been used to evaluate new components, configurations, materials, and shapes of implants. The greatest advantage of the photoelastic method is the ability to visualize the stresses in complex structures, such as oral structures, and to observe the stress patterns in the whole model, allowing the researcher to localize and quantify the stress magnitude. Strain gauges can be used to assess in vivo and in vitro stress in prostheses, implants, and teeth. Some authors use the strain gauge technique with photoelasticity or FEM techniques. These methodologies can be widely applied in dentistry, mainly in the research field. Therefore, they can guide further research and clinical studies by predicting some disadvantages and streamlining clinical time.

Bright solitons in Bose-Einstein condensates with field-induced dipole moments

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A Critical Review of Properties of Darunavir and Analytical Methods for Its Determination

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Impact of insecticide resistance on the field control of Aedes aegypti in the State of São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Assessment of CT numbers in limited and medium field-of-view scans taken using Accuitomo 170 and Veraviewepocs 3De cone-beam computed tomography scanners

To assess the influence of anatomic location on the relationship between computed tomography (CT) number and X-ray attenuation in limited and medium field-of-view (FOV) scans. Materials and Methods Tubes containing solutions with different concentrations of K2HPO4 were placed in the tooth sockets of a human head phantom. Cone-beam computed tomography (CBCT) scans were acquired, and CT numbers of the K2HPO4 solutions were measured. The relationship between CT number and K2HPO4 concentration was examined by linear regression analyses. Then, the variation in CT number according to anatomic location was examined. Results The relationship between K2HPO4 concentration and CT number was strongly linear. The slopes of the linear regressions for the limited FOVs were almost 2-fold lower than those for the medium FOVs. The absolute CT number differed between imaging protocols and anatomic locations. Conclusion There is a strong linear relationship between X-ray attenuation and CT number. The specific imaging protocol and anatomic location of the object strongly influence this relationship.

Perturbative coherence in field theory

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Book Review of Cetacean Societies: Field Studies Of Whales And Dolphins Edited by I. Mann, R. C. Connor, P. L. Tyack & H. Whitehead

Studying the sociobiology and behavioral ecology of cetaceans is particularly challenging due in large part to the aquatic environment in which they live. Nevertheless, many of the obstacles traditionally associated with data gathering on tree-ranging whales, dolphins and porpoises are rapidly being overcome, and are now far less formidable. During the past several decades, marine mammal scientists equipped with innovative research methods and new technologies have taken field-based behavioral studies to a new level of sophistication. In some cases, as is true for bottlenose dolphins, killer whales, sperm whales and humpback whales, modern research paradigms in the marine environment are comparable to present-day studies of terrestrial mammal social systems. Cetacean Society stands testament to the relatively recent advances in marine mammal science, and to those scientists, past and present, whose diligence has been instrumental in shaping the discipline.

A Field-Test of Rhodamine B as a Biomarker in Raccoons

Rhodamine B is a dye that when ingested results in fluorescent bands in growing hair and whiskers of many mammals. Previous research at Wildlife Services’ (WS) National Wildlife Research Center (NWRC) found that rhodamine B is a successful biomarker in raccoon whiskers and that raccoons do not have a taste aversion to the dye when it comprises ≤ 3% of a bait. Our study assessed the ease of bait distribution, whisker collection, and evaluation of the biomarker for potential use in the Oral Rabies Vaccination (ORV) program administered by the WS National Rabies Management Program (NRMP). In collaboration with WS operations personnel from Ohio and Michigan, 750 fishmeal polymer baits each containing 150 mg of rhodamine B were hand distributed at NASA’s Plum Brook Station, Sandusky, Ohio in the summer of 2008. Four weeks after baits were distributed whiskers from 162 raccoons were collected. Wildlife Services biologists and technicians evaluated the whiskers for fluorescence using a handheld UV magnifying lamp. Biologists then sent the whiskers to the NWRC, Ft. Collins, Colorado for confirmation of fluorescence under a UV microscope. Results suggest a high level of agreement between the two methods of evaluation. Surveys completed by biologists confirmed that the ease of use, less invasive sampling techniques and promptness of results obtained through the use of rhodamine B are advantageous to the tetracycline biomarker presently used by the ORV program. All participants recommended further evaluation of rhodamine B for its inclusion in future efforts requiring biomarker evaluation.

A NEW “PAROTRAP” ADAPTED FROM THE MAC TRAP FOR CAPTURING LIVE PARAKEETS IN THE FIELD

The Rose-ringed parakeet (Psittacula krameri [Scopdi]) has been reported (Roberts, 1974; Bashir, 1978; Beg, 1978; and DeGrazio, 1978) as a serious bird pest of maize, sunflower, rape seeds, and fruit crops, particularly citrus, mangoes, and guavas, in Pakistan. Estimated annual losses to maize grown for seed alone amount to about 97,000 tons, worth about Pak. Rs. 150 million or US $15 million (Roberts, 1978). Paradoxically, this handsome bright green parakeet is highly esteemed in the pet trade; and limited numbers are also marketed locally and sometimes exported to neighboring countries, particularly the Arab Gulf Emirates, as caged pets. Traditional control methods aimed at scaring or chasing birds from the crops, usually with noise-making devices, are costly; furthermore, they have largely been unsuccessful and time consuming because they require human patrolling before and after normal working hours. They provide at best only temporary relief. The aim of this study was to develop a new decoy trap based on the Modified Australian Crow Trap (MAC), which we propose to call the PAROTRAP, and to evaluate its effectiveness and potential in capturing live parakeets in the field as a possible solution to the parakeet problem, as well as promoting the economic exploitation of trapped parakeets for the pet trade. The study was undertaken during March and June 1979 as a part of the UNDP/FAO Project No. PAK/71/554, assisting Pakistan Vertebrate Pest Control Centre in developing and improving control techniques to prevent or reduce bird damage to important crops. Our earlier trials showed that parakeets could be induced to enter a conventionally designed MAC trap, and that after some time they learned how to escape from it. Therefore, a series of minor modifications were introduced and field tested.

HAWAIIAN SUGAR CANE RAT CONTROL METHODS AND PROBLEMS

The problem of rats in our Hawaiian sugar cane fields has been with us for a long time. Early records tell of heavy damage at various times on all the islands where sugar cane is grown. Many methods were tried to control these rats. Trapping was once used as a control measure, a bounty was used for a time, gangs of dogs were trained to catch the rats as the cane was harvested. Many kinds of baits and poisons were used. All of these methods were of some value as long as labor was cheap. Our present day problem started when the labor costs started up and the sugar industry shifted to long cropping. Until World War II cane was an annual crop. After the war it was shifted to a two year crop, three years in some places. Depending on variety, location, and soil we raise 90 to 130 tons of sugar cane per acre, which produces 7 to 15 tons of sugar per acre for a two year crop. This sugar brings about $135 dollars per ton. This tonnage of cane is a thick tangle of vegetation. The cane grows erect for almost a year, as it continues to grow it bends over at the base. This allows the stalk to rest on the ground or on other stalks of cane as it continues to grow. These stalks form a tangled mat of stalks and dead leaves that may be two feet thick at the time of harvest. At the same time the leafy growing portion of the stalk will be sticking up out of the mat of cane ten feet in the air. Some of these individual stalks may be 30 feet long and still growing at the time of harvest. All this makes it very hard to get through a cane field as it is one long, prolonged stumble over and through the cane. It is in this mat of cane that our three species of rats live. Two species are familiar to most people in the pest control field. Rattus norvegicus and Rattus rattus. In the latter species we include both the black rat and the alexandrine rats, their habits seem to be the same in Hawaii. Our third rat is the Polynesian rat, Rattus exlans, locally called the Hawaiian rat. This is a small rat, the average length head to tip of tail is nine inches and the average body weight is 65 grams. It has dark brownish fur like the alexandrine rats, and a grey belly. It is found in Indonesia, on most of the islands of Oceania and in New Zealand. All three rats live in our cane fields and the brushy and forested portions of our islands. The norway and alexandrine rats are found in and around the villages and farms, the Polynesian rat is only found in the fields and waste areas. The actual amount of damage done by rats is small, but destruction they cause is large. The rats gnaw through the rind of the cane stalk and eat the soft juicy and sweet tissues inside. They will hollow out one to several nodes per stalk attacked. The effect to the cane stalk is like ringing a tree. After this attack the stalk above the chewed portion usually dies, and sometimes the lower portion too. If the rat does not eat through the stalk the cane stalk could go on living and producing sugar at a reduced rate. Generally an injured stalk does not last long. Disease and souring organisms get in the injury and kill the stalk. And if this isn't enough, some insects are attracted to the injured stalk and will sometimes bore in and kill it. An injured stalk of cane doesn't have much of a chance. A rat may only gnaw out six inches of a 30 foot stalk and the whole stalk will die. If the rat only destroyed what he ate we could ignore them but they cause the death of too much cane. This dead, dying, and souring cane cause several direct and indirect tosses. First we lose the sugar that the cane would have produced. We harvest all of our cane mechanically so we haul the dead and souring cane to the mill where we have to grind it with our good cane and the bad cane reduces the purity of the sugar juices we squeeze from the cane. Rats reduce our income and run up our overhead.

On the motion of particles in covariant Horava-Lifshitz gravity and the meaning of the A-field

We studied the low energy motion of particles in the general covariant. version of Horava-Lifshitz gravity proposed by Horava and Melby-Thompson. Using a scalar field coupled to gravity according to the minimal substitution recipe proposed by da Silva and taking the geometrical optics limit, we could write an effective relativistic metric for a general solution. As a result, we discovered that the equivalence principle is not in general recovered at low energies, unless the spatial Laplacian of A vanishes. Finally, we analyzed the motion on the spherical symmetric solution proposed by Horava and Melby-Thompson, where we could find its effective line element and compute spin-0 geodesics. Using standard methods we have shown that such an effective metric cannot reproduce Newton's gravity law even in the weak gravitational field approximation. (C) 2011 Elsevier B.V All rights reserved.

H-1 low- and high-field NMR study of the effects of plasma treatment on the oil and water fractions in crude heavy oil

The chemical and physical properties of a Brazilian heavy oil submitted to plasma treatment were investigated by H-1 low-and high-field nuclear magnetic resonance (NMR) combined to the characterization of rheological properties, thermogravimetry and measurement of basic sediments and water (BSW) content. The crude oil was treated in a dielectric barrier discharge plasma reactor, using natural gas, CO2 or H-2 as working gas. The results indicated a large drop in the water content of the plasma-treated samples as compared to the crude oil, giving rise to a reduction in the viscosity. No significant chemical change was produced in the oil portion itself, as observed by H-1 NMR. The water contents determined by H-1 low-field NMR analyses agreed well with those obtained by BSW, indicating the low-field NMR methods as a useful tool for following the effects of plasma treatments on heavy oils, allowing the separation of the effects caused on the water and oil fractions. (C) 2011 Elsevier Ltd. All rights reserved.

QUANTUM FIELD THEORY IN GRAPHENE

This is a short nontechnical introduction to applications of the Quantum Field Theory methods to graphene. We derive the Dirac model from the tight binding model and describe calculations of the polarization operator (conductivity). Later on, we use this quantity to describe the Quantum Hall Effect, light absorption by graphene, the Faraday effect, and the Casimir interaction.

The place of (explicit) grammar within the methods and approaches of foreign language teaching: in the north, in the centre or on the margins?

This article analyzes the role that has been attributed to grammar throughout the history of foreign language teaching, with special emphasis on methods and approaches of the twentieth century. In order to support our argument, we discuss the notion of grammar by proposing a conceptual continuum that includes the main meanings of the term which are relevant to our research. We address as well the issue of "pedagogical grammar" and consider the position of grammar in the different approaches of the "era of the methods" and the current "post-method condition" in the field of language teaching and learning. The findings presented at the end of the text consist of recognizing the central role that grammar has played throughout the history of the methods and approaches, where grammar has always been present by the definition of the contents' progression. The rationale that we propose for this is the recognition of the fact that the dissociation between what is said and how it is said can not be more than theoretical and, thus, artificial.

Examination of the performance of different pointwise linear regression progression criteria to detect glaucomatous visual field change

Background: We aimed to investigate the performance of five different trend analysis criteria for the detection of glaucomatous progression and to determine the most frequently and rapidly progressing locations of the visual field. Design: Retrospective cohort. Participants or Samples: Treated glaucoma patients with =8 Swedish Interactive Thresholding Algorithm (SITA)-standard 24-2 visual field tests. Methods: Progression was determined using trend analysis. Five different criteria were used: (A) =1 significantly progressing point; (B) =2 significantly progressing points; (C) =2 progressing points located in the same hemifield; (D) at least two adjacent progressing points located in the same hemifield; (E) =2 progressing points in the same Garway-Heath map sector. Main Outcome Measures: Number of progressing eyes and false-positive results. Results: We included 587 patients. The number of eyes reaching a progression endpoint using each criterion was: A = 300 (51%); B = 212 (36%); C = 194 (33%); D = 170 (29%); and E = 186 (31%) (P = 0.03). The numbers of eyes with positive slopes were: A = 13 (4.3%); B = 3 (1.4%); C = 3 (1.5%); D = 2 (1.1%); and E = 3 (1.6%) (P = 0.06). The global slopes for progressing eyes were more negative in Groups B, C and D than in Group A (P = 0.004). The visual field locations that progressed more often were those in the nasal field adjacent to the horizontal midline. Conclusions: Pointwise linear regression criteria that take into account the retinal nerve fibre layer anatomy enhances the specificity of trend analysis for the detection glaucomatous visual field progression.