Uppsala University

About: Uppsala University is a education organization based out in Uppsala, Sweden. It is known for research contribution in the topics: Population & Gene. The organization has 36485 authors who have published 107509 publications receiving 4220668 citations. The organization is also known as: Uppsala universitet & uu.se.

Small fields: nonequilibrium radiation dosimetry.

Abstract: Advances in radiation treatment with beamlet-based intensity modulation, image-guided radiation therapy, and stereotactic radiosurgery (including specialized equipments like CyberKnife, Gamma Knife, tomotherapy, and high-resolution multileaf collimating systems) have resulted in the use of reduced treatment fields to a subcentimeter scale. Compared to the traditional radiotherapy with fields > or =4 x 4 cm2, this can result in significant uncertainty in the accuracy of clinical dosimetry. The dosimetry of small fields is challenging due to nonequilibrium conditions created as a consequence of the secondary electron track lengths and the source size projected through the collimating system that are comparable to the treatment field size. It is further complicated by the prolonged electron tracks in the presence of low-density inhomogeneities. Also, radiation detectors introduced into such fields usually perturb the level of disequilibrium. Hence, the dosimetric accuracy previously achieved for standard radiotherapy applications is at risk for both absolute and relative dose determination. This article summarizes the present knowledge and gives an insight into the future procedures to handle the nonequilibrium radiation dosimetry problems. It is anticipated that new miniature detectors with controlled perturbations and corrections will be available to meet the demand for accurate measurements. It is also expected that the Monte Carlo techniques will increasingly be used in assessing the accuracy, verification, and calculation of dose, and will aid perturbation calculations of detectors used in small and highly conformal radiation beams. rican Association of Physicists in Medicine.

Health-related quality of life in parents of school-age children with Asperger Syndrome or High-Functioning Autism.

Abstract: The estimated prevalence rate of Pervasive Developmental Disorders (PDD) in children is 6 per 1.000. Parenting children who are intellectually impaired and have PDDs is known to be linked to the impaired well-being of the parents themselves. However, there is still little available data on health-related quality of life (HRQL) in parents of children with Asperger Syndrome (AS) and High-Functioning Autism (HFA), or other PDD diagnoses in children of normal intelligence. The present study aimed to evaluate aspects of HRQL in parents of school-age children with AS/HFA and the correlates with child behaviour characteristics. The sample consisted of 31 mothers and 30 fathers of 32 children with AS/HFA and 30 mothers and 29 fathers of 32 age and gender matched children with typical development. Parental HRQL was surveyed by the use of the 12 Item Short Form Health Survey (SF-12) which measures physical and mental well-being. The child behaviour characteristics were assessed using the structured questionnaires: The High-Functioning Autism Spectrum Screening Questionnaire (ASSQ) and The Strengths and Difficulties Questionnaire (SDQ). The mothers of children with AS/HFA had lower SF-12 scores than the controls, indicating poorer physical health. The mothers of children with AS/HFA also had lower physical SF-12 scores compared to the fathers. In the AS/HFA group, maternal health was related to behaviour problems such as hyperactivity and conduct problems in the child. Mothers but not fathers of children with AS/HFA reported impaired HRQL, and there was a relationship between maternal well-being and child behaviour characteristics.

Creating value through mutual commitment to business network relationships

Abstract: A structural model of business relationship development in a business network context is formulated and tested on delta from the European International Marketing and Purchasing (IMP) project. The e ...

Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant

Abstract: The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on expe...