542 research outputs found
Retrospektive Bestimmung der elektromagnetischen Exposition durch analoge Rundfunksender im Rahmen von KiSS
Im Rahmen einer epidemiologischen Fall-Kontroll-Studie zur Untersuchung eines möglichen Zusammenhangs zwischen der Häufigkeit kindlicher Leukämien und elektromagnetischer Strahlung (,,KiSS" &ndash; <b>Ki</b>ndliche Leukämien und Expositionen in der Umgebung von hochfrequenten <b>S</b>ende<b>s</b>tationen) soll die Exposition durch leistungsstarke analoge Rundfunksender retrospektiv (Zeitraum 1982&ndash;2003) quantifiziert werden. Die zu betrachtenden Sendernetze für AM-Hörfunk, FM-Hörfunk und analoges Fernsehen unterscheiden sich nicht nur hinsichtlich der Modulationsart und der von den Einzelsendern abgestrahlten Leistung, sondern auch in der Netzkonfiguration und den je nach Wellenbereich verschiedenen Strahlungseigenschaften der Sendeantennen. Damit sind bei diesen drei Rundfunkdiensten sowohl die absolute Größe als auch die räumliche Struktur der hervorgerufenen Exposition verschieden. Es wird dargelegt, wie die für die Prognose der Rundfunkversorgung verwendeten Rechenverfahren zur Modellierung der Feldstärke für die Modellierung der Exposition herangezogen und durch Kontrollmessungen validiert werden und wie trotz Wahrung der Vertraulichkeit der dabei unabdingbar zu verwendenden Senderbetriebsdaten eine unerwünschte Beeinflussung der Studienergebnisse durch die Senderbetreiber ausgeschlossen wird
Metabolic analysis of the interaction between plants and herbivores
Insect herbivores by necessity have to deal with a large arsenal of plant defence metabolites. The levels of defence compounds may be increased by insect damage. These induced plant responses may also affect the metabolism and performance of successive insect herbivores. As the chemical nature of induced responses is largely unknown, global metabolomic analyses are a valuable tool to gain more insight into the metabolites possibly involved in such interactions. This study analyzed the interaction between feral cabbage (Brassica oleracea) and small cabbage white caterpillars (Pieris rapae) and how previous attacks to the plant affect the caterpillar metabolism. Because plants may be induced by shoot and root herbivory, we compared shoot and root induction by treating the plants on either plant part with jasmonic acid. Extracts of the plants and the caterpillars were chemically analysed using Ultra Performance Liquid Chromatography/Time of Flight Mass Spectrometry (UPLCT/MS). The study revealed that the levels of three structurally related coumaroylquinic acids were elevated in plants treated on the shoot. The levels of these compounds in plants and caterpillars were highly correlated: these compounds were defined as the ‘metabolic interface’. The role of these metabolites could only be discovered using simultaneous analysis of the plant and caterpillar metabolomes. We conclude that a metabolomics approach is useful in discovering unexpected bioactive compounds involved in ecological interactions between plants and their herbivores and higher trophic levels.
Does training with amplitude modulated tones affect tone-vocoded speech perception?
Temporal-envelope cues are essential for successful speech perception. We asked here whether training on stimuli containing temporal-envelope cues without speech content can improve the perception of spectrally-degraded (vocoded) speech in which the temporal-envelope (but not the temporal fine structure) is mainly preserved. Two groups of listeners were trained on different amplitude-modulation (AM) based tasks, either AM detection or AM-rate discrimination (21 blocks of 60 trials during two days, 1260 trials; frequency range: 4Hz, 8Hz, and 16Hz), while an additional control group did not undertake any training. Consonant identification in vocoded vowel-consonant-vowel stimuli was tested before and after training on the AM tasks (or at an equivalent time interval for the control group). Following training, only the trained groups showed a significant improvement in the perception of vocoded speech, but the improvement did not significantly differ from that observed for controls. Thus, we do not find convincing evidence that this amount of training with temporal-envelope cues without speech content provide significant benefit for vocoded speech intelligibility. Alternative training regimens using vocoded speech along the linguistic hierarchy should be explored
Psychophysical Investigations into the Role of Low-Threshold C Fibres in Non-Painful Affective Processing and Pain Modulation
We recently showed that C low-threshold mechanoreceptors (CLTMRs) contribute to touch-evoked pain (allodynia) during experimental muscle pain. Conversely, in absence of ongoing pain, the activation of CLTMRs has been shown to correlate with a diffuse sensation of pleasant touch. In this study, we evaluated (1) the primary afferent fibre types contributing to positive (pleasant) and negative (unpleasant) affective touch and (2) the effects of tactile stimuli on tonic muscle pain by varying affective attributes and frequency parameters.
Psychophysical observations were made in 10 healthy participants. Two types of test stimuli were applied: stroking stimulus using velvet or sandpaper at speeds of 0.1, 1.0 and 10.0 cm/s; focal vibrotactile stimulus at low (20 Hz) or high (200 Hz) frequency. These stimuli were applied in the normal condition (i.e. no experimental pain) and following the induction of muscle pain by infusing hypertonic saline (5%) into the tibialis anterior muscle.
These observations were repeated following the conduction block of myelinated fibres by compression of sciatic nerve. In absence of muscle pain, all participants reliably linked velvet-stroking to pleasantness and sandpaper-stroking to unpleasantness (no pain). Likewise,
low-frequency vibration was linked to pleasantness and high-frequency vibration to unpleasantness. During muscle pain, the application of previously pleasant stimuli resulted
in overall pain relief, whereas the application of previously unpleasant stimuli resulted in overall pain intensification. These effects were significant, reproducible and persisted following the blockade of myelinated fibres. Taken together, these findings suggest the role of low-threshold C fibres in affective and pain processing. Furthermore, these observations suggest that temporal coding need not be limited to discriminative aspects of tactile processing,
but may contribute to affective attributes, which in turn predispose individual responses towards excitatory or inhibitory modulation of pain
Anti-proliferative effect of Rosmarinus officinalis L. extract on human melanoma A375 cells
Rosemary (Rosmarinus officinalis L.) has been used since ancient times in traditional medicine, while nowadays various rosemary formulations are increasingly exploited by alternative medicine to cure or prevent a wide range of health disorders. Rosemary's bioproperties have prompted scientific investigation, which allowed us to ascertain antioxidant, anti-inflammatory, cytostatic, and cytotoxic activities of crude extracts or of pure components. Although there is a growing body of experimental work, information about rosemary's anticancer properties, such as chemoprotective or anti-proliferative effects on cancer cells, is very poor, especially concerning the mechanism of action. Melanoma is a skin tumor whose diffusion is rapidly increasing in the world and whose malignancy is reinforced by its high resistance to cytotoxic agents; hence the availability of new cytotoxic drugs would be very helpful to improve melanoma prognosis. Here we report on the effect of a rosemary hydroalcoholic extract on the viability of the human melanoma A375 cell line. Main components of rosemary extract were identified by liquid chromatography coupled to tandem mass spectrometry (LC/ESI-MS/MS) and the effect of the crude extract or of pure components on the proliferation of cancer cells was tested by MTT and Trypan blue assays. The effect on cell cycle was investigated by using flow cytometry, and the alteration of the cellular redox state was evaluated by intracellular ROS levels and protein carbonylation analysis. Furthermore, in order to get information about the molecular mechanisms of cytotoxicity, a comparative proteomic investigation was performed
Upper limb amputees can be induced to experience a rubber hand as their own
We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body
Development and Phenotype of Heart Failure in Long-Term Survivors of Childhood Cancer:The CVSS Study
BACKGROUND: The CVSS (Cardiac and Vascular Late Sequelae in Long-Term Survivors of Childhood Cancer) study aimed to investigate the prevalence of different stages of heart failure (HF) in childhood cancer survivors (CCSs) compared with the general population. METHODS AND RESULTS: A total of 1002 CCSs (age range, 23– 48 years) diagnosed with neoplasia before an age of 15 years underwent a comprehensive cardiovascular screening. An age-and sex-matched sample from the population-based GHS (Gutenberg Health Study) served as a comparison group. Although prevalence of HF was significantly higher in CCSs, prevalence of different HF stages varied strongly by specific tumor history. Compared with the population, the prevalence ratio was 2.6 (95% CI, 2.4– 2.8) for HF stage A and 4.6 (95% CI, 4.1– 5.1) for the composite of HF stage B to D in an age-and sex-adjusted Poisson regression model. Multivariable linear regression, adjusting for tumor entities, age, sex, and cardiovascular risk factors, revealed a lower left ventricular ejection fraction in patients with history of bone tumors (β, −4.30 [95% CI, −5.70 to −2.80]), soft tissue sarcoma (β, −1.60 [95% CI, −2.90 to −0.30]), and renal tumors (β, −1.60 [95% CI, −2.80 to −0.29]) compared with the population. The same model for the diastolic marker, ratio of the peak early diastolic filling velocity/lateral mitral annular early diastolic velocity, showed an association only with cardiovascular risk factors but not with tumor entities. CONCLUSIONS: The prevalence of HF stage A to D was significantly higher among long-term CCSs compared with the population and varied strongly by tumor entity. Systolic dysfunction was primarily associated with tumor entities, whereas diastolic dysfunction was associated with a higher burden of cardiovascular risk factors in CCSs.</p
Development and phenotype of heart failure in long-term survivors of childhood cancer : the CVSS study
BACKGROUND: The CVSS (Cardiac and Vascular Late Sequelae in Long-Term Survivors of Childhood Cancer) study aimed to
investigate the prevalence of different stages of heart failure (HF) in childhood cancer survivors (CCSs) compared with the
general population.
METHODS AND RESULTS: A total of 1002 CCSs (age range, 23–48years) diagnosed with neoplasia before an age of 15years
underwent a comprehensive cardiovascular screening. An age- and sex-matched sample from the population-based GHS
(Gutenberg Health Study) served as a comparison group. Although prevalence of HF was significantly higher in CCSs, preva lence of different HF stages varied strongly by specific tumor history. Compared with the population, the prevalence ratio
was 2.6 (95% CI, 2.4–2.8) for HF stage A and 4.6 (95% CI, 4.1–5.1) for the composite of HF stage B to D in an age- and sex adjusted Poisson regression model. Multivariable linear regression, adjusting for tumor entities, age, sex, and cardiovascular
risk factors, revealed a lower left ventricular ejection fraction in patients with history of bone tumors (β, −4.30 [95% CI, −5.70
to −2.80]), soft tissue sarcoma (β, −1.60 [95% CI, −2.90 to −0.30]), and renal tumors (β, −1.60 [95% CI, −2.80 to −0.29]) com pared with the population. The same model for the diastolic marker, ratio of the peak early diastolic filling velocity/lateral mitral
annular early diastolic velocity, showed an association only with cardiovascular risk factors but not with tumor entities.
CONCLUSIONS: The prevalence of HF stage A to D was significantly higher among long-term CCSs compared with the popula tion and varied strongly by tumor entity. Systolic dysfunction was primarily associated with tumor entities, whereas diastolic
dysfunction was associated with a higher burden of cardiovascular risk factors in CCSs
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