Fundamental solution of the Volkov problem (characteristic representation)

The characteristic representation, or Goursat problem, for the Klein-Fock-Gordon equation with Volkov interaction [1] is regarded. It is shown that in this representation the explicit form of the Volkov propagator can be obtained. Using the characteristic representation technique, the Schwinger integral [2] in the Volkov problem can be calculated

Superluminal solutions to the Klein-Gordon equation and a causality problem

We present a new axially symmetric monochromatic free-space solution to the Klein-Gordon equation propagating with a superluminal group velocity and show that it gives rise to an imaginary part of the causal propagator outside the light cone. We address the question about causality of the spacelike paths and argue that the signal with a well-defined wavefront formed by the superluminal modes would propagate in vacuum with the light speed.Comment: to be published in Physics Letters A, an additional reference to the paper by Buttiker and Washbur

A mechanistic framework for a priori pharmacokinetic predictions of orally inhaled drugs

The fate of orally inhaled drugs is determined by pulmonary pharmacokinetic (PK) processes such as particle deposition, pulmonary drug dissolution, and mucociliary clearance. Although each single process has been systematically investigated, a quantitative understanding on their interaction remains limited and hence identifying optimal drug and formulation characteristics for orally inhaled drugs is still challenging. To investigate this complex interplay, the pulmonary processes can be integrated into mathematical models. However, existing modeling attempts considerably simplify these processes or are not systematically evaluated against (clinical) data. In this work, we developed a mathematical framework based on physiologically-structured population equations to integrate all relevant pulmonary processes mechanistically. A tailored numerical resolution strategy was chosen and the mechanistic model was evaluated systematically against different clinical datasets. Without any parameter estimation based on individual study data, the developed model simultaneously predicted (1) lung retention profiles of inhaled insoluble particles, (2) particle size-dependent PK of inhaled monodisperse particles, (3) PK differences between inhaled fluticasone propionate and budesonide, and (4) PK differences between healthy volunteers and asthmatic patients. Finally, to identify the most impactful optimization criteria for orally inhaled drugs, we investigated the impact of input parameters on both pulmonary and systemic exposure. Solubility of the inhaled drug did not have any relevant impact on local and systemic PK. Instead, pulmonary dissolution rate, particle size, tissue affinity, and systemic clearance were impactful potential optimization parameters. In the future, the developed prediction framework should be considered a powerful tool to identify optimal drug and formulation characteristics

The Complex Interplay of Pulmonary Kinetic Processes

The inhalation route is frequently used to administer drugs for the management of respiratory diseases such as asthma or chronic obstructive pulmonary disease. Compared with other routes of administration, inhalation offers a number of advantages in the treatment of these diseases. For example, via inhalation, a drug is directly delivered to the target organ, conferring high pulmonary drug concentrations and low systemic drug concentrations. Therefore, drug inhalation is typically associated with high pulmonary efficacy and minimal systemic side effects. The lung, as a target, represents an organ with a complex structure and multiple pulmonary-specific pharmacokinetic processes, including (1) drug particle/droplet deposition; (2) pulmonary drug dissolution; (3) mucociliary and macrophage clearance; (4) absorption to lung tissue; (5) pulmonary tissue retention and tissue metabolism; and (6) absorptive drug clearance to the systemic perfusion. In this review, we describe these pharmacokinetic processes and explain how they may be influenced by drug-, formulation- and device-, and patient-related factors. Furthermore, we highlight the complex interplay between these processes and describe, using the examples of inhaled albuterol, fluticasone propionate, budesonide, and olodaterol, how various sequential or parallel pulmonary processes should be considered in order to comprehend the pulmonary fate of inhaled drugs

Engineering of Neutral Excitons and Exciton Complexes in Transition Metal Dichalcogenide Monolayers through External Dielectric Screening

In order to fully exploit the potential of transition metal dichalcogenide monolayers (TMD-MLs), the well-controlled creation of atomically sharp lateral heterojunctions within these materials is highly desirable. A promising approach to create such heterojunctions is the local modulation of the electronic structure of an intrinsic TMD-ML via dielectric screening induced by its surrounding materials. For the realization of this non-invasive approach, an in-depth understanding of such dielectric effects is required. We report on the modulations of excitonic transitions in TMD-MLs through the effect of dielectric environments including low-k and high-k dielectric materials. We present absolute tuning ranges as large as 37 meV for the optical band gaps of WSe 2 and MoSe 2 MLs and relative tuning ranges on the order of 30% for the binding energies of neutral excitons in WSe 2 MLs. The findings suggest the possibility to reduce the electronic band gap of WSe 2 MLs by 120 meV, paving the way towards dielectrically defined lateral heterojunctions.Comment: 11 pages + 6 pages supporting informatio

Avaliação de risco e de fatores preditores para desenvolvimento de úlcera por pressão em pacientes críticos

Em uma época de rápidas transformações, globalização da economia e mudanças de comportamento das pessoas que, buscando a sua cidadania, exigem e cobram melhores produtos e serviços. Várias instituições, inclusive as de saúde, tem se preocupado com o tema e muitas delas caminham na implantação de programas de qualidade nos seus processos de prestação de serviços. Assim, os Serviços de Enfermagem, como parte integrante de instituições, enfrentam desafios no sentido de atender esta demanda. O enfermeiro, então, desempenha um importante papel no sentido de direcionar suas ações para o atendimento das reais necessidades da população, imprimindo qualidade aos serviços. Com isso, observou-se uma preocupação entre estes profissionais quanto à construção e validação de indicadores de assistência, que permitam comparação e reflexão quanto à prática profissional. O uso de indicadores de qualidade assistencial serve para avaliar o impacto das ações de enfermagem no processo do cuidado ao paciente internado. O interesse do estudo se perpetua na escassez de bibliografia sobre indicadores da assistência de enfermagem em Centro de Tratamento Intensivo e os indicadores que apresentam relação íntima com o cuidado neste local são: úlcera de pressão, flebite, perda de artefato e queda. Tendo como objetivo analisar os indicadores de qualidade da assistência de enfermagem no Centro de Tratamento Intensivo do Hospital Universitário Cassiano Antônio Moraes através de um estudo descritivo, prospectivo com abordagem quantitativa. Descritores: cuidado de enfermagem, indicadores de qualidade, terapia intensivaIntroduction: Pressure ulcers in critically ill patients have been constituted as a serious management and care, creating major challenges to nursing. Objectives: Estimate the incidence of pressure ulcers in critically ill patients, identify factors associated with its development and. evaluate the accuracy of risk assessment scales of Braden and Waterlow Method: This is a cohort study conducted from March to June 2013, with 77 patients admitted to the intensive care units, which consisted of an initial assessment of variables associated with intrinsic and extrinsic factors, among which: the metabolic profile of patients, daily application of risk assessment scales (Braden and Waterlow) on admission and every 48 hours, and assessment and classification of ulcers into categories Results: The incidence was found to be 22 %, 17 patients developed 32 pressure ulcers, predominantly located in the sacral region (47%) and in class I (72%). Regarding the metabolic profile, the bearer of ulcer, showed albumin, transferrin and low lymphocyte count. In bivariate analysis the variables found were: hospitalization for longer than 10 days (71%), type of surgical hospitalization (53%), congestive heart failure (24%), norepinephrine (29%) and high risk Scale Braden. Braden and Waterlow Scale, presented, respectively, high sensibility (41% and 71%) and low specificity (21% and 47%) in the three assessments. The cutoff scores found in the first, second and third evaluation were 12, 12 and 11 for the Braden Scale and 16, 15 and 14 for the Waterlow scale. Conclusion: The study showed a high incidence of pressure ulcers, identified associated factors with it and evaluated the Braden Scale to be a good screening tool and the Waterlow a better predictive power tool and emphasizing the importance of the systematization of nursing actions and the use of appropriate technology in the prevention of injury

COMO CONSTRUIR E UTILIZAR UMA BACIA HIDROGRÁFICA DE FORMA INTERDISCIPLINAR E INTEGRADA

O presente trabalho pretende mostrar que um organizador prévio, como a maquete de uma microbacia hidrográfica,pode ser facilmente construído e utilizado de forma interdisciplinar, em qualquer escola. O mesmo material é utilizado por todos os docentes, cada um explorando temas relacionados ao objeto, facilitando a aprendizagem e ampliando os conhecimentos sobre o assunto,analisado sob diferentes ópticas (MOREIRA, 1982)