14 resultados para LIGHT TRANSMISSION
em BORIS: Bern Open Repository and Information System - Berna - Suiça
Resumo:
Clinical trials have reported statistically significant and clinically relevant effects of homeopathic preparations. We applied ultraviolet (UV) spectroscopy to investigate the physical properties of homeopathic preparations and to contribute to an understanding of the not-yet-identified mode of action. In previous investigations, homeopathic preparations had significantly lower UV light transmissions than controls. The aim of this study was to explore the possible effects of external factors (UV light and temperature) on the homeopathic preparations. Homeopathic centesimal (c) dilutions, 1c to 30c, of copper sulfate (CuSO(4)), decimal dilutions of sulfur (S(8)), 1x to 30x, and controls (succussed potentization medium) were prepared, randomized, and blinded. UV transmission was measured at six different time points after preparation (from 4 to 256 days). In addition, one series of samples was exposed to UV light of a sterilization lamp for 12 h, one was incubated at 37 degrees Celsius for 24 h, and one was heated to 90 degrees Celsius for 15 min. UV light transmission values from 190 or 220 nm to 340 nm were measured several times and averaged. After each exposure, UV transmission of the homeopathic preparations of CuSO(4) was significantly reduced compared to the controls, particularly after heating to 37 degrees Celsius. Overall, the nonexposed CuSO(4) preparations did not show significantly lower UV transmission compared to controls; however, the pooled subgroup of measurements at days 26, 33, and 110 yielded significant differences. UV light transmission for S(8) preparations did not show any differences compared to controls. Our conclusion is that exposure to external factors, incubation at 37 degrees Celsius in particular, increases the difference in light transmission of homeopathic CuSO(4) preparations compared to controls.
Resumo:
Objective Homeopathic globules are commonly used in clinical practice, while research focuses on liquid potencies. Sequential dilution and succussion in their production process has been proposed to change the physico-chemical properties of the solvent(s). It has been reported that aqueous potencies of various starting materials showed significant differences in ultraviolet light transmission compared to controls and between different dilution levels. The aim of the present study was to repeat and expand these experiments to homeopathic globules. Methods Globules were specially produced for this study by Spagyros AG (Gümligen, Switzerland) from 6 starting materials (Aconitum napellus, Atropa belladonna, phosphorus, sulfur, Apis mellifica, quartz) and for 6 dilution levels (6x, 12x, 30c, 200c, 200CF (centesimal discontinuous fluxion), 10,000CF). Native globules and globules impregnated with solvents were used as controls. Globules were dissolved in ultrapure water, and absorbance in the ultraviolet range was measured. The average absorbance from 200 to 340 nm was calculated and corrected for differences between measurement days and instrumental drift. Results Statistically significant differences were found for A. napellus, sulfur, and A. mellifica when normalized average absorbance of the various dilution levels from the same starting material (including control and solvent control globules) was compared. Additionally, absorbance within dilution levels was compared among the various starting materials. Statistically significant differences were found among 30c, 200c and 200CF dilutions. Conclusion This study has expanded previous findings from aqueous potencies to globules and may indicate that characteristics of aqueous high dilutions may be preserved and detectable in dissolved globules.
Resumo:
Drug-drug interaction between statins metabolised by cytochrome P450 3A4 and clopidogrel have been claimed to attenuate the inhibitory effect of clopidogrel. However, published data regarding this drug-drug interaction are controversial. We aimed to determine the effect of fluvastatin and atorvastatin on the inhibitory effect of dual antiplatelet therapy with acetylsalicylic acid (ASA) and clopidogrel. One hundred one patients with symptomatic stable coronary artery disease undergoing percutaneous coronary intervention and drug-eluting stent implantation were enrolled in this prospective randomised study. After an interval of two weeks under dual antiplatelet therapy with ASA and clopidogrel, without any lipid-lowering drug, 87 patients were randomised to receive a treatment with either fluvastatin 80 mg daily or atorvastatin 40 mg daily in addition to the dual antiplatelet therapy for one month. Platelet aggregation was assessed using light transmission aggregometry and whole blood impedance platelet aggregometry prior to randomisation and after one month of receiving assigned statin and dual antiplatelet treatment. Platelet function assessment after one month of statin and dual antiplatelet therapy did not show a significant change in platelet aggregation from 1st to 2nd assessment for either statin group. There was also no difference between atorvastatin and fluvastatin treatment arms. In conclusion, neither atorvastatin 40 mg daily nor fluvastatin 80 mg daily administered in combination with standard dual antiplatelet therapy following coronary drug-eluting stent implantation significantly interfere with the antiaggregatory effect of ASA and clopidogrel.
Resumo:
We sought to determine a potential interaction between statins and antiplatelet therapy with aspirin and clopidogrel. Previous laboratory studies have shown a possible drug-drug interaction of statins metabolized by cytochrome P450 3A4 and clopidogrel (prodrug metabolized by cytochrome P450 3A4), resulting in an impaired inhibitory effect of clopidogrel on platelet aggregation. However, conclusive prospective data assessing this potentially relevant interaction are lacking. In 73 patients, 23 with previous coronary stent thrombosis (ST) (ST group) and 50 without coronary ST (control group), platelet aggregation was measured 3 times in monthly intervals using light transmission aggregometry (adenosine diphosphate [ADP] and arachidonic acid induction). Measurements were carried out with aspirin monotherapy (100 mg/day), dual antiplatelet therapy with aspirin plus clopidogrel (75 mg/day), and additional treatment of 20 mg/day of atorvastatin or 40 mg/day of pravastatin. ADP (5 and 20 micromol)-induced platelet aggregation was significantly decreased with clopidogrel (p <0.001) but remained stable under additional treatment with atorvastatin or pravastatin in the 2 groups. Patients with previous ST showed a higher ADP-induced aggregation level than control subjects. This difference was not influenced by clopidogrel or statin treatment. In conclusion, patients with previous ST show a higher aggregation level than control subjects independent of statin treatment. Atorvastatin and pravastatin do not interfere with the antiaggregatory effect of aspirin and clopidogrel. In conclusion, drug-drug interaction between dual antiplatelet therapy and atorvastatin or pravastatin seems not to be associated with ST.
Resumo:
The anatomy of the domestic duck lung was studied macroscopically, by casting and by light, transmission, and scanning electron microscopy. The lung had four categories of secondary bronchi (SB), namely, the medioventral (MV, 4-5), laterodorsal (LD, 6-10), lateroventral (LV, 2-4), and posterior secondary bronchi (PO, 36-44). The neopulmonic parabronchi formed an intricate feltwork on the ventral third of the lung and inosculated those from the other SB. The lung parenchyma was organized into cylindrical parabronchi separated by thin septa containing blood vessels. Atria were shallow and well-fortified by epithelial ridges reinforced by smooth muscle bundles and gave rise to 2-6 elongate infundibulae. Air capillaries arose either directly from the atria or from infundibulae and were tubular or globular in shape with thin interconnecting branches. The newly described spatial disposition of the conducting air conduits closely resembles that of the chicken. This remarkable similarity between the categories, numbers, and 3D arrangement of the SB in the duck and chicken points to a convergence in function-oriented design. To illuminate airflow dynamics in the avian lung, precise directions of airflow in the various categories of SB and parabronchi need to be characterized.
Resumo:
In the long run, the widespread use of slide scanners by pathologists requires an adaptation of teaching methods in histology and cytology in order to target these new possibilities of image processing and presentation via the internet. Accordingly, we were looking for a tool with the possibility to teach microscopic anatomy, histology, and cytology of tissue samples which would be able to combine image data from light and electron microscopes independently of microscope suppliers. With the example of a section through the villus of jejunum, we describe here how to process image data from light and electron microscopes in order to get one image-stack which allows a correlation of structures from the microscopic anatomic to the cytological level. With commercially available image-presentation software that we adapted to our needs, we present here a platform which allows for the presentation of this new but also of older material independently of microscope suppliers.
Resumo:
The most abundant cell types in the hemolymph of Cupiennius salei are plasmatocytes (70–80%) and granulocytes (20–30%). Both cells differ in shape, cytochemical and transmission electron microscopy staining of their cytoplasma and granules. According to MALDI-IMS (matrix-assisted laser desorption ionization mass spectrometry imaging), granulocytes exhibit ctenidin 1 (9510 Da) and ctenidin 3 (9568 Da), SIBD-1 (8675 Da), and unknown peptides with masses of 2207 and 6239 Da. Plasmatocytes exhibit mainly a mass of 6908 Da. Unknown peptides with masses of 1546 and 1960 Da were detected in plasmatocytes and granulocytes. Transmission electron microscopy confirms the presence of two compounds in one granule and cytochemical staining (light microscopy) tends to support this view. Two further hemocyte types (cyanocytes containing hemocyanin and prehemocytes as stem cells) are only rarely detected in the hemolymph. These four hemocyte types constitute the cellular part of the spider immune system and this is discussed in view of arachnid hemocyte evolution.
Resumo:
OBJECTIVES The occurrence of multinucleated giant cells (MNGCs) on bone substitute materials has been recognized for a long time. However, there have been no studies linking material characteristics with morphology of the MNGCs. The aim was to analyze the qualitative differences of MNGCs on two commercially available calcium phosphate bone substitute materials retrieved from bone defects. MATERIAL AND METHODS Six defects were prepared bilaterally in the mandibular body of three mini pigs. The defects were randomly grafted with either deproteinized bovine bone mineral (DBBM) or biphasic calcium phosphate (BCP). After a healing period of four weeks, bone blocks were embedded in LR White resin. Three consecutive sections per defect were analyzed as follows: two with light microscopy using toluidine blue and tartrate-resistant acid phosphatase (TRAP) staining and one with transmission electron microscopy. RESULTS Multinucleated giant cells appeared on both biomaterials. On BCP, MNGCs had a flat morphology and were not observed in resorption lacunae. On DBBM, the MNGCs appeared more round and were often found in shallow concavities. MNGCs on both biomaterials demonstrated a varying degree of TRAP staining, with a tendency toward higher staining intensity of MNGCs on BCP. At the ultrastructural level, signs of superficial dissolution of BCP together with phagocytosis of minor fragments were observed. MNGCs on the surface of DBBM demonstrated sealing zones and ruffled borders, both features of mature osteoclasts. CONCLUSION MNGCs demonstrated distinctly different histological features depending on the bone substitute material used. Further research is warranted to understand the clinical implications of these morphological observations.
Resumo:
We investigate experimentally the transmission properties of single sub-wavelength coaxial apertures in thin metal films (t = 110 nm). Enhanced transmission through a single sub-wavelength coaxial aperture illuminated with a strongly focused radially polarized light beam is reported. In our experiments we achieved up to four times enhanced transmission through a single coaxial aperture as compared to a (hollow) circular aperture with the same outer diameter.We attribute this enhancement of transmission to the excitation of a TEM-mode for illumination with radially polarized light inside the single coaxial aperture. A strong polarization contrast is observed between the transmission for radially and azimuthally polarized illumination. Furthermore, the observed transmission through a single coaxial aperture can be strongly reduced if surface plasmons are excited. The experimental results are in good agreement with finite difference time domain (FDTD) simulations.
Resumo:
ABSTRACT: Nanotechnology in its widest sense seeks to exploit the special biophysical and chemical properties of materials at the nanoscale. While the potential technological, diagnostic or therapeutic applications are promising there is a growing body of evidence that the special technological features of nanoparticulate material are associated with biological effects formerly not attributed to the same materials at a larger particle scale. Therefore, studies that address the potential hazards of nanoparticles on biological systems including human health are required. Due to its large surface area the lung is one of the major sites of interaction with inhaled nanoparticles. One of the great challenges of studying particle-lung interactions is the microscopic visualization of nanoparticles within tissues or single cells both in vivo and in vitro. Once a certain type of nanoparticle can be identified unambiguously using microscopic methods it is desirable to quantify the particle distribution within a cell, an organ or the whole organism. Transmission electron microscopy provides an ideal tool to perform qualitative and quantitative analyses of particle-related structural changes of the respiratory tract, to reveal the localization of nanoparticles within tissues and cells and to investigate the 3D nature of nanoparticle-lung interactions.This article provides information on the applicability, advantages and disadvantages of electron microscopic preparation techniques and several advanced transmission electron microscopic methods including conventional, immuno and energy-filtered electron microscopy as well as electron tomography for the visualization of both model nanoparticles (e.g. polystyrene) and technologically relevant nanoparticles (e.g. titanium dioxide). Furthermore, we highlight possibilities to combine light and electron microscopic techniques in a correlative approach. Finally, we demonstrate a formal quantitative, i.e. stereological approach to analyze the distributions of nanoparticles in tissues and cells.This comprehensive article aims to provide a basis for scientists in nanoparticle research to integrate electron microscopic analyses into their study design and to select the appropriate microscopic strategy.
Resumo:
Mesoscopic 3D imaging has become a widely used optical imaging technique to visualize intact biological specimens. Selective plane illumination microscopy (SPIM) visualizes samples up to a centimeter in size with micrometer resolution by 3D data stitching but is limited to fluorescent contrast. Optical projection tomography (OPT) works with fluorescent and nonfluorescent contrasts, but its resolution is limited in large samples. We present a hybrid setup (OPTiSPIM) combining the advantages of each technique. The combination of fluorescent and nonfluorescent high-resolution 3D data into integrated datasets enables a more extensive representation of mesoscopic biological samples. The modular concept of the OPTiSPIM facilitates incorporation of the transmission OPT modality into already established light sheet based imaging setups.
Resumo:
Background: High dilutions of various starting materials, e.g. copper sulfate, Hypericum perforatum and sulfur, showed significant differences from controls and amongst different dilution levels in ultraviolet light (UV) transmission [1,2]. Exposure of high dilutions to external physical factors such as UV light or elevated temperature (37°C) also yielded significantly different UV transmissions compared to unexposed dilutions [2,3]. In a study with highland frogs it was shown that animals incubated with thyroxine 30c but not with thyroxine 30c exposed to electromagnetic fields (EMFs) of a microwave oven or mobile phone metamorphosed more slowly than control animals [4]. Aims: The aim was to test whether the EMF of a mobile phone influences the UV absorbance of dilutions of quartz and Atropa belladonna (AB). Methodology: Commercially available dilutions of 6x, 12x, 15x, 30x in H2O and 19% ethanol of quartz (SiO2) and of 4x, 6x, 12x, 15x, 30x in H2O and 19% ethanol of AB were used in the experiments (Weleda AG, Arlesheim, Switzerland). Four samples of each dilution were exposed to the EMF of a mobile phone (Philips, Savvy Dual Band) at 900 MHz with an output of 2 W for 3 h, while control samples (4 of each dilution) were kept in a separate room. Absorbance of the samples in the UV range (from 190 to 340 nm) was measured in a randomized order with a Shimadzu UV-1800 spectrophotometer equipped with an auto sampler. In total 5 separate measurement days will be carried out for quartz and for AB dilutions. The average absorbance from 200 to 340 nm and from 200 to 240 nm was compared among dilution levels using a Kruskal-Wallis test and between exposed and unexposed samples using a Mann-Whitney-U test. Results: Preliminary results after 2 measurement days indicated that for quartz the absorbance of the various dilution levels was different from each other (except 12x and 15x), and that samples exposed to an EMF did not show a difference in UV absorbance from unexposed samples. Preliminary results after one measurement day indicated that for AB the absorbance of the various dilution levels was different from each other. The samples exposed to an EMF did not show a difference in UV absorbance from unexposed samples (except 4x in the range from 200 – 240 nm). Conclusions: These results suggest that exposure of high dilutions of quartz and AB to a mobile phone EMF as used here does not alter UV absorbance of these dilutions. The final results will show whether this holds true.
Resumo:
Background: High and ultra-high dilutions of various starting materials, e.g. copper sulfate, Hypericum perforatum and sulfur, showed significant differences in ultraviolet light (UV) transmission from controls and amongst different dilution levels [1,2]. Verum and placebo globules of Aconitum napellus 30c or calcium carbonate/quercus e cortice 6x from the same packs as used in previous clinical trials and dissolved in water could be distinguished by UV spectroscopy [3]. However, it was unclear whether the differences in UV absorbance originated from specific characteristics of the starting materials, from differences in the production of verum and placebo globules, and/or other unknown interference factors. Aims: The aim of this study was to investigate whether globules produced with high and ultra-high dilutions (6x, 12x, 30c, 200c, 200CF (centesimal discontinuous fluxion), 10,000CF) of various starting materials (Aconitum napellus, Atropa belladonna, phosphorus, sulfur, Apis mellifica, quartz) could be distinguished by UV spectroscopy. Methodology: The globules were specially produced for this study by Spagyros AG (Gümligen, Switzerland) and differed only in the starting materials of the dilutions (but not in the batch of globules or ethanol used). Globules were dissolved in water at 10 mg/ml, in quadruplicates, approximately 22 h prior to the measurements. Absorbance of the samples in the UV range (from 190 to 340 nm) was measured in a randomized order with a Shimadzu double beam UV-1800 spectrophotometer equipped with an auto sampler. Samples of each starting material were prepared and measured on 5 independent days. The daily variations of the spectrophotometer as well as the drift during the measurements were corrected for. The average absorbance from 200 to 340 nm was compared among various starting materials within equal dilution levels using a Kruskal-Wallis test. Results: Statistically significant differences were found among 30c (Figure 1), 200c and 200CF dilutions of the various starting materials. No differences were found among 6x, 12x and 10,000CF dilutions. Conclusions: Globules prepared from high dilutions of various starting materials may show significantly different UV absorbance when dissolved in water. References [1] Wolf U, Wolf M, Heusser P, Thurneysen A, Baumgartner S. Homeopathic preparations of quartz, sulfur and copper sulfate assessed by UV-spectroscopy. Evid Based Complement Alternat Med. 2011;2011:692798. [2] Klein SD, Sandig A, Baumgartner S, Wolf U. Differences in median ultraviolet light transmissions of serial homeopathic dilutions of copper sulfate, Hypericum perforatum, and sulfur. Evid Based Complement Alternat Med. 2013;2013:370609. [3] Klein SD, Wolf U. Investigating homeopathic verum and placebo globules with ultraviolet spectroscopy. Forsch Komplementmed. 2013, accepted.
Resumo:
Stray light contamination reduces considerably the precision of photometric of faint stars for low altitude spaceborne observatories. When measuring faint objects, the necessity of coping with stray light contamination arises in order to avoid systematic impacts on low signal-to-noise images. Stray light contamination can be represented by a flat offset in CCD data. Mitigation techniques begin by a comprehensive study during the design phase, followed by the use of target pointing optimisation and post-processing methods. We present a code that aims at simulating the stray-light contamination in low-Earth orbit coming from reflexion of solar light by the Earth. StrAy Light SimulAtor (SALSA) is a tool intended to be used at an early stage as a tool to evaluate the effective visible region in the sky and, therefore to optimise the observation sequence. SALSA can compute Earth stray light contamination for significant periods of time allowing missionwide parameters to be optimised (e.g. impose constraints on the point source transmission function (PST) and/or on the altitude of the satellite). It can also be used to study the behaviour of the stray light at different seasons or latitudes. Given the position of the satellite with respect to the Earth and the Sun, SALSA computes the stray light at the entrance of the telescope following a geometrical technique. After characterising the illuminated region of the Earth, the portion of illuminated Earth that affects the satellite is calculated. Then, the flux of reflected solar photons is evaluated at the entrance of the telescope. Using the PST of the instrument, the final stray light contamination at the detector is calculated. The analysis tools include time series analysis of the contamination, evaluation of the sky coverage and an objects visibility predictor. Effects of the South Atlantic Anomaly and of any shutdown periods of the instrument can be added. Several designs or mission concepts can be easily tested and compared. The code is not thought as a stand-alone mission designer. Its mandatory inputs are a time series describing the trajectory of the satellite and the characteristics of the instrument. This software suite has been applied to the design and analysis of CHEOPS (CHaracterizing ExOPlanet Satellite). This mission requires very high precision photometry to detect very shallow transits of exoplanets. Different altitudes and characteristics of the detector have been studied in order to find the best parameters, that reduce the effect of contamination. © (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.