412 research outputs found
On the microlocal properties of the range of systems of principal type
The purpose of this paper is to study microlocal conditions for inclusion
relations between the ranges of square systems of pseudodifferential operators
which fail to be locally solvable. The work is an extension of earlier results
for the scalar case in this direction, where analogues of results by L.
H\"ormander about inclusion relations between the ranges of first order
differential operators with coefficients in which fail to be locally
solvable were obtained. We shall study the properties of the range of systems
of principal type with constant characteristics for which condition (\Psi) is
known to be equivalent to microlocal solvability.Comment: Added Theorem 4.7, Corollary 4.8 and Lemma A.4, corrected misprints.
The paper has 40 page
Solvability of subprincipal type operators
In this paper we consider the solvability of pseudodifferential operators in
the case when the principal symbol vanishes of order at a nonradial
involutive manifold . We shall assume that the operator is of
subprincipal type, which means that the :th inhomogeneous blowup at
of the refined principal symbol is of principal type with Hamilton
vector field parallel to the base , but transversal to the symplectic
leaves of at the characteristics. When this blowup
reduces to the subprincipal symbol. We also assume that the blowup is
essentially constant on the leaves of , and does not satisfying the
Nirenberg-Treves condition (). We also have conditions on the vanishing
of the normal gradient and the Hessian of the blowup at the characteristics.
Under these conditions, we show that is not solvable.Comment: Changed the formulation of Theorem 2.15, added an assuption.
Corrected errors and clarified the arguments. Added reference
Accumulation of 125I-labelled thiouracil and propylthiouracil in murine melanotic melanomas.
We have shown that thioamides are incorporated as false precursors into melanin during its synthesis. To be clinically useful in the diagnosis or therapy of melanotic melanomas, they would have to be tagged with an appropriate isotope or possibly a cytotoxic moiety. 125I-Thiouracil (125I-TU) is here shown to be accumulated in the melanin of melanotic melanomas transplanted into mice in a similar way as is 14C-thiouracil (14C-TU). 125I-TU gives tumour/liver and tumour/muscle ratios up to 22 and 778 respectively, at 4 days after administration. 125I-TU is accumulated by melanoma cells in vitro more effectively than 14C-TU (125I-TU/14C-TU, 2.7), while the in vivo accumulation into melanomas is slightly lower for 125I-TU as compared to 14C-TU (125I-TU/14C-TU, 0.35). This appears to be due to a partial deiodination (less than 14% of the dose within 4 days) and probably a more rapid excretion of 125I-TU or its metabolite(s). The accumulation of radioactivity in the thyroid can essentially be eliminated by pretreatment with potassium iodide and/or thyroxine. 125I-Propylthiouracil is also accumulated in melanotic melanoma cells in vivo and in vitro, but at a lower level than in 125I-TU and 14C-TU
Cardiorespiratory fitness is associated with hard and light intensity physical activity but not time spent sedentary in 10–14 year old schoolchildren: the HAPPY study
Sedentary behaviour is a major risk factor for developing chronic diseases and is associated with low cardiorespiratory fitness in adults. It remains unclear how sedentary behaviour and different physical activity subcomponents are related to cardiorespiratory fitness in children. The purpose of this study was to assess how sedentary behaviour and different physical activity subcomponents are associated with 10–14 year-old schoolchildren's cardiorespiratory fitness
Associations of sedentary behaviour, physical activity, blood pressure and anthropometric measures with cardiorespiratory fitness in children with cerebral palsy
Background - Children with cerebral palsy (CP) have poor cardiorespiratory fitness in comparison to their peers with typical development, which may be due to low levels of physical activity. Poor cardiorespiratory fitness may contribute to increased cardiometabolic risk. Purpose - The aim of this study was to determine the association between sedentary behaviour, physical activity and cardiorespiratory fitness in children with CP. An objective was to determine the association between cardiorespiratory fitness, anthropometric measures and blood pressure in children with CP. Methods- This study included 55 ambulatory children with CP [mean (SD) age 11.3 (0.2) yr, range 6-17 yr; Gross Motor Function Classification System (GMFCS) levels I and II]. Anthropometric measures (BMI, waist circumference and waist-height ratio) and blood pressure were taken. Cardiorespiratory fitness was measured using a 10 m shuttle run test. Children were classified as low, middle and high fitness according to level achieved on the test using reference curves. Physical activity was measured by accelerometry over 7 days. In addition to total activity, time in sedentary behaviour and light, moderate, vigorous, and sustained moderate-to-vigorous activity (≥10 min bouts) were calculated. Results - Multiple regression analyses revealed that vigorous activity (β = 0.339, p<0.01), sustained moderate-to-vigorous activity (β = 0.250, p<0.05) and total activity (β = 0.238, p<0.05) were associated with level achieved on the shuttle run test after adjustment for age, sex and GMFCS level. Children with high fitness spent more time in vigorous activity than children with middle fitness (p<0.05). Shuttle run test level was negatively associated with BMI (r2 = -0.451, p<0.01), waist circumference (r2 = -0.560, p<0.001), waist-height ratio (r2 = -0.560, p<0.001) and systolic blood pressure (r2 = -0.306, p<0.05) after adjustment for age, sex and GMFCS level. Conclusions - Participation in physical activity, particularly at a vigorous intensity, is associated with high cardiorespiratory fitness in children with CP. Low cardiorespiratory fitness is associated with increased cardiometabolic risk
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Adopting a healthy lifestyle when pregnant and obese - an interview study three years after childbirth
Background: Obesity during pregnancy is increasing and is related to life-threatening and ill-health conditions in both mother and child. Initiating and maintaining a healthy lifestyle when pregnant with body mass index (BMI) ≥ 30 kg/m2 can improve health and decrease risks during pregnancy and of long-term illness for the mother and the child. To minimise gestational weight gain women with BMI ≥ 30 kg/m2 in early pregnancy were invited to a lifestyle intervention including advice and support on diet and physical activity in Gothenburg, Sweden. The aim of this study was to explore the experiences of women with BMI ≥ 30 kg/m2 regarding minimising their gestational weight gain, and to assess how health professionals' care approaches are reflected in the women's narratives.
Methods: Semi-structured interviews were conducted with 17 women who had participated in a lifestyle intervention for women with BMI ≥ 30 kg/m2 during pregnancy 3 years earlier. The interviews were digitally recorded and transcribed in full. Thematic analysis was used.
Results: The meaning of changing lifestyle for minimising weight gain and of the professional's care approaches is described in four themes: the child as the main motivation for making healthy changes; a need to be seen and supported on own terms to establish healthy routines; being able to manage healthy activities and own weight; and need for additional support to maintain a healthy lifestyle.
Conclusions: To support women with BMI ≥ 30 kg/m2 to make healthy lifestyle changes and limit weight gain during pregnancy antenatal health care providers should 1) address women's weight in a non-judgmental way using BMI, and provide accurate and appropriate information about the benefits of limited gestational weight gain; 2) support the woman on her own terms in a collaborative relationship with the midwife; 3) work in partnership to give the woman the tools to self-manage healthy activities and 4) give continued personal support and monitoring to maintain healthy eating and regular physical activity habits after childbirth involving also the partner and family
Upregulation of CRABP1 in human neuroblastoma cells overproducing the Alzheimer-typical Aβ42 reduces their differentiation potential
<p>Abstract</p> <p>Background</p> <p>Alzheimer's disease (AD) is characterized by neurodegeneration and changes in cellular processes, including neurogenesis. Proteolytic processing of the amyloid precursor protein (APP) plays a central role in AD. Owing to varying APP processing, several β-amyloid peptides (Aβ) are generated. In contrast to the form with 40 amino acids (Aβ<sub>40</sub>), the variant with 42 amino acids (Aβ<sub>42</sub>) is thought to be the pathogenic form triggering the pathological cascade in AD. While total-Aβ effects have been studied extensively, little is known about specific genome-wide effects triggered by Aβ<sub>42 </sub>or Aβ<sub>40 </sub>derived from their direct precursor C99.</p> <p>Methods</p> <p>A combined transcriptomics/proteomics analysis was performed to measure the effects of intracellularly generated Aβ peptides in human neuroblastoma cells. Data was validated by real-time polymerase chain reaction (real-time PCR) and a functional validation was carried out using RNA interference.</p> <p>Results</p> <p>Here we studied the transcriptomic and proteomic responses to increased or decreased Aβ<sub>42 </sub>and Aβ<sub>40 </sub>levels generated in human neuroblastoma cells. Genome-wide expression profiles (Affymetrix) and proteomic approaches were combined to analyze the cellular response to the changed Aβ<sub>42</sub>- and Aβ<sub>40</sub>-levels. The cells responded to this challenge with significant changes in their expression pattern. We identified several dysregulated genes and proteins, but only the cellular retinoic acid binding protein 1 (CRABP1) was up-regulated exclusively in cells expressing an increased Aβ<sub>42</sub>/Aβ<sub>40 </sub>ratio. This consequently reduced all-trans retinoic acid (RA)-induced differentiation, validated by CRABP1 knock down, which led to recovery of the cellular response to RA treatment and cellular sprouting under physiological RA concentrations. Importantly, this effect was specific to the AD typical increase in the Aβ<sub>42</sub>/Aβ<sub>40 </sub>ratio, whereas a decreased ratio did not result in up-regulation of CRABP1.</p> <p>Conclusion</p> <p>We conclude that increasing the Aβ<sub>42</sub>/Aβ<sub>40 </sub>ratio up-regulates CRABP1, which in turn reduces the differentiation potential of the human neuroblastoma cell line SH-SY5Y, but increases cell proliferation. This work might contribute to the better understanding of AD neurogenesis, currently a controversial topic.</p
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