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L Braun

Publications and source records attributed to L Braun.

At least 19 recordsLinked to original sources
PubMed2005

Vibronic energies and spectra of molecular dimers.

We consider three distinct methods of calculating the vibronic levels and absorption spectra of molecular dimers coupled by dipole-dipole interactions. The first method is direct diagonalization of the vibronic Hamiltonian in a basis of monomer eigenstates. The second method is to use creation and annihilation operators leading in harmonic approximation to the Jaynes-Cummings Hamiltonian. The adiabatic approximation to this problem provides insight into spectral behavior in the weak and strong coupling limits. The third method, which serves as a check on the accuracy of the previous methods, is a numerically exact solution of the time-dependent Schrodinger equation. Using these methods, dimer spectra are calculated for three separate dye molecules and show good agreement with measured spectra.

Journal Article↗
PubMed2005

[Diagnosis and differentiation of children with language development disorders. What role can be attributed to intelligence?].

BACKGROUND: Specific language impairment (SLI) is defined as a developmental disorder in which language comprehension and the child's ability to use expressive spoken language is markedly below the appropriate level for his or her mental age. The intelligence of SLI children is in the normal range, while their language abilities are impaired. "Normal intelligence", the defining feature of SLI is questioned in this study. PATIENTS AND METHODS: Using IDIS (an inventory of diagnostic information in language impairment), we examined 138 children aged 5 and 6 years with severe language impairment; 108 SLI and 30 LI children. Various indicators of speech and language such as articulation, the ability to discriminate sounds, lexicon, grammar and pragmatic abilities but also auditory and visual perception, auditory and visual memory, fine and gross motor function were assessed. RESULTS: The performance of the SLI children was significantly higher in most of the tests than that of the LI children. Factor analysis showed that the two groups also differed in the structure of performance. Auditory short-term memory was reduced in most children irrespective of intelligence. CONCLUSIONS: We propose the retention of the differentiation of subgroups of developmental speech and language disorders depending on the level of intelligence.

Child↗
PubMed2005

Physical activity staging distribution: establishing a heuristic using multiple studies.

The purpose of this study was to identify the population prevalence across the stages of change (SoC) for regular physical activity and to establish the prevalence of people at risk. With support from the National Institutes of Health, the American Heart Association, and the Robert Wood Johnson Foundation, nine Behavior Change Consortium studies with a common physical activity SoC measure agreed to collaborate and share data. The distribution pattern identified in these predominantly reactively recruited studies was Precontemplation (PC) = 5% (+/- 10), Contemplation (C) = 10% (+/- 10), Preparation (P) = 40% (+/- 10), Action = 10% (+/- 10), and Maintenance = 35% (+/- 10). With reactively recruited studies, it can be anticipated that there will be a higher percentage of the sample that is ready to change and a greater percentage of currently active people compared to random representative samples. The at-risk stage distribution (i.e., those not at criteria or PC, C, and P) was approximately 10% PC, 20% C, and 70% P in specific samples and approximately 20% PC, 10% C, and 70% P in the clinical samples. Knowing SoC heuristics can inform public health practitioners and policymakers about the population's motivation for physical activity, help track changes over time, and assist in the allocation of resources.

Behavioral Research↗
PubMed2004

Stable Bacillus thuringiensis (Bt) toxin content in interspecific F1 and backcross populations of wild Brassica rapa after Bt gene transfer.

Stable expression of a transgene may lead to increased fitness for wild plants after acquiring the transgene via crop-weed hybridization. Here, we investigate the stability of Bt toxin content in wild Brassica rapa acquiring the Bt gene from Bt Brassica napus. The Bt toxin content in nine Bt-expressing B. napus lines was 0.80-1.70 micro g/g leaf tissue throughout the growing season. These nine lines were crossed with three accessions of wild B. rapa and the Bt gene was successfully transferred to interspecific hybrids (F1) and successive backcross generations (BC1 to BC4). The Bt toxin level in F1 and BC progenies containing the Bt gene remained at 0.90-3.10 micro g/g leaf tissue. This study indicates that the Bt gene can persist and be stably expressed in wild B. rapa.

Bacillus thuringiensis↗
PubMed2003

Hybridization between transgenic Brassica napus L. and its wild relatives: Brassica rapa L., Raphanus raphanistrum L., Sinapis arvensis L., and Erucastrum gallicum (Willd.) O.E. Schulz.

The frequency of gene flow from Brassica napus L. (canola) to four wild relatives, Brassica rapa L., Raphanus raphanistrum L., Sinapis arvensis L. and Erucastrum gallicum (Willd.) O.E. Schulz, was assessed in greenhouse and/or field experiments, and actual rates measured in commercial fields in Canada. Various marker systems were used to detect hybrid individuals: herbicide resistance traits (HR), green fluorescent protein marker (GFP), species-specific amplified fragment length polymorphisms (AFLPs) and ploidy level. Hybridization between B. rapa and B. napus occurred in two field experiments (frequency approximately 7%) and in wild populations in commercial fields (approximately 13.6%). The higher frequency in commercial fields was most likely due to greater distance between B. rapa plants. All F(1) hybrids were morphologically similar to B. rapa, had B. napus- and B. rapa-specific AFLP markers and were triploid (AAC, 2n=29 chromosomes). They had reduced pollen viability (about 55%) and segregated for both self-incompatible and self-compatible individuals (the latter being a B. napus trait). In contrast, gene flow between R. raphanistrum and B. napus was very rare. A single R. raphanistrum x B. napus F1 hybrid was detected in 32,821 seedlings from the HR B. napus field experiment. The hybrid was morphologically similar to R. raphanistrum except for the presence of valves, a B. napus trait, in the distorted seed pods. It had a genomic structure consistent with the fusion of an unreduced gamete of R. raphanistrum and a reduced gamete of B. napus (RrRrAC, 2n=37), both B. napus- and R. raphanistrum-specific AFLP markers, and had <1% pollen viability. No hybrids were detected in the greenhouse experiments (1,534 seedlings), the GFP field experiment (4,059 seedlings) or in commercial fields in Québec and Alberta (22,114 seedlings). No S. arvensis or E. gallicum x B. napus hybrids were detected (42,828 and 21,841 seedlings, respectively) from commercial fields in Saskatchewan. These findings suggest that the probability of gene flow from transgenic B. napus to R. raphanistrum, S. arvensis or E. gallicum is very low (<2-5 x 10(-5)). However, transgenes can disperse in the environment via wild B. rapa in eastern Canada and possibly via commercial B. rapa volunteers in western Canada.

Brassicaceae↗
PubMed2003

Mamestra configurata serpin-1 homologues: cloning, localization and developmental regulation.

A screen of a Mamestra configurata (bertha armyworm) midgut cDNA library identified three types of cDNA clones that resemble the Manduca sexta serpin-1 gene family. Two serpins, 1b and 1c, possess a common conserved serpin amino terminal scaffold domain but bear no similarity to any members of the M. sexta gene family within the reactive centre loop. These serpins differ from one another by only two amino acids in the reactive centre loop (S(363)-->P) and serpin signature (M(369)-->T) regions. The other member, denoted serpin-1a, is closely related to the M. sexta serpin-1Z. M. configurata serpins as a group were expressed in all insect developmental stages including eggs, larvae and adult moths. Within larvae, serpin gene expression was restricted to the early to middle instar developmental phase and mainly in the fat body and hemocytes. Stress imposed by starvation strongly induced expression in fat body and to a lesser degree in alimentary organs, nervous system and Malphigian tubules. Conversely, starvation decreased expression in hemocytes. Wounding or inoculation with bacteria did not induce serpin gene transcription but did lead to the formation of higher and lower molecular weight forms, presumably serpin-protease complexes and resultant truncated serpin, respectively. Two dimensional PAGE and western blotting analysis revealed at least 12 distinct serpins consisting primarily of neutral, but also highly acidic and basic isoforms, as well as additional high and low molecular weight immuno-reactive species. Serpins-1b/1c are the more prominent serpin isoforms and are expressed predominantly in the fat body and subsequently exported to the hemolymph as revealed by western blotting and immunolocalization. The serpin-1b/1c isoform was found only as the fully glycosylated species within the hemolymph. Hemolymph protease activity was comprised mostly of serine proteases whose overall activity increased dramatically at the onset of the molt concomitant with a sharp decline in serpin gene expression.

Amino Acid Sequence↗
PubMed2003

[The incurable patient under the guidance of his doctor and relatives].

Caring for an incurable patient during the last phases of his life belongs to the hardest duties of a doctor and requires empathy and sympathy. It is important to find the narrow pathway between truth and hope, to take the fear from the patient, that he would be left alone, and to preserve always his human dignity.

Attitude to Death↗
PubMed2002

Changes in cysteine protease activity and localization during midgut metamorphosis in the crucifer root maggot (Delia radicum).

We show that differential localization and/or activation of two cysteine protease activities occur at the onset of dipteran midgut metamorphosis. A 26 kDa cysteine protease activity was associated specifically with midgut tissues of late third instar larvae. Starvation of mid third instar larvae simulated the onset of prepupation and resulted in loss of the 26 kDa protease activity. A cDNA clone encoding a cysteine protease, termed DrCP1, was isolated and shown to be highly similar to those from Sarcophaga peregrina and Drosophila melanogaster (DmCP1). DrCP1 mRNA was present in all developmental stages including eggs, larvae, pupae and adults, but was highly induced at the onset of the larval-pupal transition and thereafter. The DrCP1 protein is localized to the exterior of the midgut tissues during the onset of the prepupal transition period, possibly in response to ecdysone. Analysis of transcription factor binding sites associated with the DmCP1 promoter indicated that elements exist that allow for both ecdysone-mediated as well as tissue-specific regulation. Based upon these and other studies we propose: (1) that the expression, activity and localization of the DrCP1-like cysteine proteases are highly regulated throughout development; and, (2) that cysteine protease activities are involved in aspects of tissue reconstruction at the onset of and during metamorphosis.

Amino Acid Sequence↗
PubMed2002

Partners for Life: a theoretical approach to developing an intervention for cardiac risk reduction.

Long-term maintenance of behavioral change to reduce health risk factors is essential to producing a positive effect on medical outcomes. This study examines whether an ongoing, long-term relationship can be used to help patients diagnosed with coronary artery disease adhere to a risk-reducing behavioral intervention and maintain healthy behavioral changes. One hundred and sixty patients with diagnosed coronary artery disease will be randomized to a standard behavioral treatment group or to a standard behavioral treatment group including a couples intervention and followed for 18 months. The treatment in both groups follows tenets of cognitive behavioral and Self-Determination Theories as well as the Transtheoretical Model of Behavior Change. In addition, the couples intervention is designed to (1) change the patient's environment to facilitate cardiac risk-reducing behavioral changes, (2) optimize social reinforcement and motivation for behavior change, and (3) decrease relationship stress. Behavioral outcomes assessed include adherence to an exercise regimen, adherence to dietary recommendations and adherence to lipid-lowering medication. Lipid values, psychological variables and relationship variables are assessed throughout the study and at follow-up. While we expect both groups of cardiac patients to successfully adapt new health behaviors, we expect the couples intervention to be superior in helping maintain long-term health behaviors.

Coronary Disease↗
PubMed2001

The regulation of the induction of vascular endothelial growth factor at the onset of diabetes in spontaneously diabetic rats.

Early induction of VEGF was studied in liver, kidney and lung of spontaneously diabetic rats. Western blot analysis, northern hybridization were applied to show the expression of VEGF in different organs. Radiolabelled hypoxia responsive element (HRE) and cAMP responsive element (CRE) oligonucleotides were assayed by electrophoretic mobility shift (EMSA) or supershift using anti ARNT and anti CREB-1 monoclonal antibodies. An increase in VEGF expression at the level of protein and mRNA was demonstrated at the beginning of the disease. EMSAs showed: a.) a binding of HIF-1 to HRE and/or CRE, b.) in the same time the binding of CREB- I was detected to both HRE and/or CRE sequences in the liver, kidney and lung of diabetic animals. Based on these in vivo observations it is supposed that HRE and CRE through the interaction between HIF-1 and CREB-1 are equally involved in the regulation of VEGF expression at the onset of diabetes.

Animals↗
PubMed2001

Role of vitamin E in ascorbate-dependent protein thiol oxidation in rat liver endoplasmic reticulum.

Addition of ascorbate or its generation from gulonolactone causes the oxidation of protein thiols and a simultaneous dehydroascorbate formation in rat liver microsomes. The participation of vitamin E in the phenomenon was studied. We measured ascorbate and protein thiol oxidation and lipid peroxidation in vitamin E deficient liver microsomes. Vitamin E deficiency partly uncoupled the two processes: ascorbate oxidation increased, while protein thiol oxidation decreased. These changes were accompanied with an accelerated lipid peroxidation in the vitamin E-deficient microsomes, which indicates the accumulation of reactive oxygen species. All these effects were reduced by the in vitro addition of vitamin E to the deficient microsomes, supporting its direct role in the process. The results demonstrate that vitamin E is a component of the protein thiol oxidizing machinery in the hepatic endoplasmic reticulum transferring electrons from the thiol groups towards oxygen.

Animals↗
PubMed2001

Protein-disulfide isomerase- and protein thiol-dependent dehydroascorbate reduction and ascorbate accumulation in the lumen of the endoplasmic reticulum.

The transport and intraluminal reduction of dehydroascorbate was investigated in microsomal vesicles from various tissues. The highest rates of transport and intraluminal isotope accumulation (using radiolabeled compound and a rapid filtration technique) were found in hepatic microsomes. These microsomes contain the highest amount of protein-disulfide isomerase, which is known to have a dehydroascorbate reductase activity. The steady-state level of intraluminal isotope accumulation was more than 2-fold higher in hepatic microsomes prepared from spontaneously diabetic BioBreeding/Worcester rats and was very low in fetal hepatic microsomes although the initial rate of transport was not changed. In these microsomes, the amount of protein-disulfide isomerase was similar, but the availability of protein thiols was different and correlated with dehydroascorbate uptake. The increased isotope accumulation was accompanied by a higher rate of dehydroascorbate reduction and increased protein thiol oxidation in microsomes from diabetic animals. The results suggest that both the activity of protein-disulfide isomerase and the availability of protein thiols as reducing equivalents can play a crucial role in the accumulation of ascorbate in the lumen of the endoplasmic reticulum. These findings also support the fact that dehydroascorbate can act as an oxidant in the protein-disulfide isomerase-catalyzed protein disulfide formation.

Animals↗
PubMed2001

Development and implementation of a science training course for breast cancer activists: Project LEAD (leadership, education and advocacy development).

OBJECTIVE: To develop and implement Project LEAD (leadership, education, and advocacy development), a science course for breast cancer activists. POPULATION: Students were breast cancer activists and other consumers, mainly affiliated with advocacy organizations in the United States of America. SETTING: Project LEAD is offered by the National Breast Cancer Coalition; the course takes place over 5 days and is offered 4 times a year, in various cities in the United States of America. RESULTS: The Project LEAD curriculum has developed over 5 years to include lectures, problem-based study groups, case studies, interactive critical appraisal sessions, a seminar by an 'expert' scientist, role play, and homework components. A core faculty has been valuable for evaluating and revising the course and has proved necessary to provide consistent high quality teaching. Course evaluations indicated that students gained critical appraisal skills, enhanced their knowledge and developed confidence in selected areas of basic science and epidemiology. CONCLUSIONS: Project LEAD comprises a unique curriculum for training breast cancer activists in science and critical appraisal. Course evaluations indicate that students gain confidence and skills from the course.

Adult↗
PubMed2001

Herb-drug interaction guide.

Herbal medicines now fall into the category of complementary medicines. With their increasing popularity, a new set of circumstances has arisen--the herb-drug interaction. In an effort to streamline the interaction information available, the author has designed two charts. The first lists the 21 most popular herbal medicines sold in Australia, sourced from the largest natural supplement manufacturer in Australia, Bullivant Natural Health Products. The second lists the 12 commonly prescribed prescription drug classes. This list was sources from F H Faulding & Co Ltd, together with Austrialian Prescriber. Specific interaction information was collated from a variety of sources-- medical and complementary medicine journals, pharmacy practice journals and respected phytotherapy tests. These tables are excerpts from these charts.

Drug Interactions↗
PubMed2001

Herb-drug interaction guide.

Herbal medicines now fall into the category of complementary medicines. With their increasing popularity, a new set of circumstances has arisen--the herb-drug interaction. In an effort to streamline the interaction information available, the author has designed two charts. The first lists the 21 most popular herbal medicines sold in Australia, sourced from the largest natural supplement manufacturer in Australia, Bullivant Natural Health Products. The second lists the 12 commonly prescribed prescription drug classes. This list was sourced from F H Faulding & Co Ltd, together with Australian Prescriber. Specific interaction information was collated from a variety of sources--medical and complementary medicine journals, pharmacy practice journals and respected phytotherapy texts. These tables are excerpts from these charts.

Australia↗