Biochemical mechanisms of the effect of environmental factors (diet, fluorine, alcohol and tobacco) on oral health

Nowadays, oral diseases are prevalent chronic diseases present in worldwide population. Dental caries results from a complex interaction between acid-producing bacteria, fermentable carbohydrates and host factors, including teeth and saliva. Risk factors for caries development include physical, biological, environmental, behavioral factors such as high numbers of cariogenic bacteria, inadequate salivary flow, poor oral hygiene and poor eating habits. Moreover, due to its efficacy in caries prevention, fluorine has been added to toothpaste, supplements and water. However, despite of its beneficial effect, excessive intake can lead to acute or chronic toxic effects, that depend on ingestion period and ingested amount, age, cardiovascular or renal problems and genetic changes. The most common adverse effects of excessive fluorine intake are dental and skeletal fluorosis. Another oral health problem is oral cancer, one of the most common cancers in the world and a highly relevant problem of global public health, mainly affecting lips and oral cavity. It is a preventable disease, where tobacco and alcohol, considered major risk factors, are present with a synergic effect in 90% of cases. Alcohol can act as a risk factor both locally and systemically, being causally associated with oropharyngeal and larynx cancer, esophageal cancer, among others.info:eu-repo/semantics/publishedVersio

Bounds on the mass of the b' quark, revisited

Recent results from the DELPHI collaboration led us to review the present bounds on the b' quark mass. We use all available experimental data for m_b' > 96 GeV to constrain the b' quark mass as a function of the Cabibbo-Kobayashi-Maskawa elements in a sequential four generations model. We find that there is still room for a b' with a mass larger than 96 GeV.Comment: 9 pages and 7 figures. REVTEX

Estimation of cancer and hereditary effect risks in a patient and in a physician after cardiac catheterization procedure

Cateterismo cardíaco é uma prática muito comum que utiliza radiação X para gerar as imagens necessárias das estruturas do paciente para diagnóstico de algumas doenças do coração. Durante o procedimento, pacientes e médicos são expostos a radiação X por longos períodos de tempo, que podem ser suficientes para causar lesões de pele e, até mesmo, aumentar o risco de aparecimento de efeitos tardios da radiação, como o desenvolvimento de câncer ou o aparecimento de efeitos hereditários. O objetivo desse estudo foi estimar, para um exame de cateterismo cardíaco, utilizando método Monte Carlo, os coeficientes de conversão de doses equivalente e efetiva e as probabilidades de desenvolvimento de câncer e do aparecimento de efeitos hereditários tanto na paciente e quanto na médica. Considerando apenas a realização de um procedimento, os riscos d e desenvolvimento de câncer e de aparecimento de efeitos hereditários, como esperado, foram maiores para a paciente. Além disso, os resultados comprovaram que o aumento da diferença de potencial no tubo, já que gera um aumento da dose em órgãos e tecidos, aumenta os riscos associados ao procedimento, tanto de desenvolvimento de câncer quanto de aparecimento de efeito hereditário. ______________________________________________________________________________________ ABSTRACT: Cardiac catheterization is a common practice that uses X-rays to create images of structures necessary for the patient's diagnosis of certain diseases of the heart. During the procedure, patients and physicians are exposed to X-rays for long periods of time, which may be sufficient to cause skin lesions and even increase the risk of developing late effects of radiation, such as the development of cancer or onset of hereditary effects. The aim of this study was to estimate, for an examination of cardiac catheterization, using Monte Carlo method, the conversion coefficients of effective and equivalent doses and the probability of developing cancer or hereditary effects in both patient and physician. Considering only the performance of a procedure, the risks of developing cancer and hereditary effects appear, as expected, were higher for the patient. In addition, the results showed that increasing the potential difference across the tube, since it generates an increase in dose to organs and tissues, increases the risks associated with the procedure

Body condition score, weight variation and reproductive performance of beef cows in rangelands from the Pantanal region

Objetivou-se avaliar a influência do escore de condição corporal (ECC) sobre a eficiência reprodutiva de vacas de cria nos períodos pré e pós-parto e a probabilidade de parição, usando o escore de condição corporal e a variação ponderal no período crítico do ciclo reprodutivo. Utilizaram-se 248 vacas multíparas mantidas em pastagens nativas distribuídas em quatro estratégias de suplementação: mistura mineral (controle); suplemento farelado; suplemento líquido; suplemento líquido para vacas e bezerros. As avaliações de peso e ECC, na escala de 1 a 9, foram realizadas no período crítico: em agosto (período pré-parto, 60-90 dias antes da parição) e em janeiro (período pós-parto e reprodutivo) durante quatro anos consecutivos. Para a análise dos anos consecutivos de reprodução, criou-se um escore de reprodução, ou seja, somou-se o número de parições de cada vaca durante os quatro anos pecuários avaliados. O escore de condição corporal nos períodos pré e pós-parto e a idade da vaca influenciaram o escore de reprodução. Portanto, para avaliação da probabilidade de parição, foram utilizadas todas as vacas, classificadas em paridas e vazias. Utilizando equações de estimação generalizadas (EEG), foi modelada a probabilidade de as matrizes serem classificadas como paridas considerando variáveis exploratórias ao longo do tempo. Para se obter probabilidade de parição superior a 80%, as vacas devem possuir escore de aproximadamente 5,5 no período pré-parto. Aproximadamente 60% das vacas paridas mantiveram ou ganharam peso no período crítico do ano, o que levou a maior probabilidade de reconcepção, similar ao observado para as vacas vazias, porém com probabilidade menor de parição. O período pré-parto é o melhor para estimar a probabilidade de parição das vacas por meio da avaliação do escore corporal. A seleção de vacas adaptadas às condições bioclimáticas do Pantanal aumenta a probabilidade de produção de um bezerro por vaca por ano. _________________________________________________________________________________ ABSTRACTThe aim of this study was to evaluate the influence of body condition score (BCS) on reproductive performance of beef cows before and after calving and to evaluate the calving probability using body condition score and weight variation during critical periods of the cow reproductive cycle. From 2001 to 2005, the body condition score was recorded in 248 multiparous cows raised in native pastures, submitted to different supplementation treatments (mineral mixture only - control; dry supplement; liquid supplement and liquid supplement for cow and calves). Weighing and body condition evaluation were made on a 1-9 point scale in August (prepartum period, 60-90 days before parturition) and January (postpartum and reproductive period). A reproduction score was created in function of the body scores in four consecutive years. Except for the treatment, the other factors (body condition score in the prepartum and postpartum periods and cow age) influenced the reproduction score. Thus, the calving probabilities were estimated for all cows. Generalized estimating equations (GEE) were used to evaluate the calving probability in function of the exploratory variables over time. Calving probability higher than 80% was obtained when cows scored 5,5 before calving. In relation to weight, the results showed that about 60% of calving cows maintained or gained weight in the postpartum period, leading to increase in the rebreeding probability. Similar situation occurred with single cows; however, the calving probability was lower. These results indicate that the calving probability using BCS is better estimated before calving. Furthermore, it indicates the presence of cows more adapted to the Pantanal climatic and feeding conditions than others

Digital Quantum Simulation with Rydberg Atoms

We discuss in detail the implementation of an open-system quantum simulator with Rydberg states of neutral atoms held in an optical lattice. Our scheme allows one to realize both coherent as well as dissipative dynamics of complex spin models involving many-body interactions and constraints. The central building block of the simulation scheme is constituted by a mesoscopic Rydberg gate that permits the entanglement of several atoms in an efficient, robust and quick protocol. In addition, optical pumping on ancillary atoms provides the dissipative ingredient for engineering the coupling between the system and a tailored environment. As an illustration, we discuss how the simulator enables the simulation of coherent evolution of quantum spin models such as the two-dimensional Heisenberg model and Kitaev's toric code, which involves four-body spin interactions. We moreover show that in principle also the simulation of lattice fermions can be achieved. As an example for controlled dissipative dynamics, we discuss ground state cooling of frustration-free spin Hamiltonians.Comment: submitted to special issue "Quantum Information with Neutral Particles" of "Quantum Information Processing