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At least 253 records · Page 14Linked to original sources
PubMed2026

When light colour matters: Spectral quality is associated with distinct small RNA candidates in Arabidopsis thaliana.

The spectral composition of incident light is perceived by plant photoreceptors and can rapidly reshape downstream gene expression programs; however, its impact on the small-RNA layer beyond annotated miRNAs remains incompletely characterized. The objective of this study was to determine whether 3 h exposure of Arabidopsis thaliana rosettes to blue, green, red, or white light at an equal photosynthetic photon flux density (PPFD) of 400 μmol m-2 s-1 is associated with distinct profiles of candidate small RNAs. A stringent discovery and post-processing workflow was applied to identify high-confidence, treatment-associated small RNA candidates beyond annotated miRNA. The miRkwood-based pipeline, combined with additional filtering and contextual annotation, recovered a compact set of candidates dominated by the blue-light treatment (41 candidates), compared with fewer candidates associated with red (8), green (6), and white light (3). Genomic-context analysis indicated that most candidate sites were intergenic, with candidates detected under green light being entirely intergenic, and overlap with transposon annotations was used to distinguish candidates arising from transposon-rich genomic space. Sequence-feature profiling revealed pronounced treatment-dependent terminal nucleotide biases at both 5' and 3' ends, consistent with spectrum-associated shifts in length-class and terminal-nucleotide signatures that are informative for AGO-loading hypotheses. Target prediction highlighted a subset of genes showing convergent targeting by multiple independent blue-associated candidates, and duplex summaries showed structured, plant-like complementarity patterns (including frequent 10-11 pairing). Together, these results indicate that 3 h exposure to wavelength-defined light at 400 μmol m-2 s-1, particularly blue light, is associated with a distinct profile of detectable candidate small RNAs in Arabidopsis leaves and identify candidate interactions for follow-up validation.

5′ nucleotide bias↗
PubMed1982

Hospital hydrotherapy pools treated with ultra violet light: bad bacteriological quality and presence of thermophilic Naegleria.

The microbiological quality of eight halogenated and two u.v.-treated hydrotherapy pools in hospitals was investigated. The microbiological quality of halogenated hydrotherapy pools was comparable to halogenated public swimming pools, although in some Pseudomonas aeruginosa and faecal pollution indicators were more frequent due to bad management. On the other hand u.v.-treated hydrotherapy pools had very bad microbiological quality. Apart from faecal pollution indicators, P. aeruginosa was present in very high numbers. Halogenated hydrotherapy pools were not highly contaminated with amoebae, and Naegleria spp. were never detected. On the other hand u.v.-treated pools contained very high numbers of thermophilic Naegleria. The Naegleria isolated were identified as N. lovaniensis, a species commonly found in association with N. fowleri. Isoenzyme analysis showed a different type of N. lovaniensis was present in each of two u.v.-treated pools.

Amoeba↗
PubMed1998

Temperature rise during polymerization of light-activated resin composites.

There has been a steady rise in the use of resin-based composites in the restoration of large posterior cavities. Visible light-activated materials have come to dominate the market for direct posterior composites because of the convenience offered to the operator by their command set nature. Manufacturers have produced more powerful light-activation units in response to concerns over inadequate depth of cure. However, some authors have warned of the danger to the dental pulp induced by excessive heat generated during polymerization. Variables governing heat generation include output intensity of the light-activation unit, quality of light filter, irradiation time, material composition and material surface-light guide exit window distance, residual dentine thickness and cavity dimensions. This in vitro study assessed the relative influence of some of these factors under controlled conditions. The findings suggest that minimum irradiation times should be used when curing bonding agents in unlined cavities where residual dentine thickness is limited and high output intensity light-activation units are employed. Material composition is identified as an important variable in determining the magnitude of the temperature rise.

Analysis of Variance↗
PubMedDate not supplied

Calculation of the circular dichroism of Chironomus hemoglobin in the light of the quality of its X-ray structure.

For the larval hemoglobin III of the insect Chironomus thummi thummi, the rotational strength of the B (Soret) and Q band is calculated with a monopole/monopole and a dipole/dipole approximation applied to the atomic co-ordinates of the X-ray structures at 2.5 and 1.4 A resolution. In previous calculations using the 2.5 A co-ordinates and with perturbing groups being restricted to aromatic side-chains, the dipole/dipole approximation clearly confirmed the negative sign observed by experiment. The predominant interactions were those of phenylalanine residues. Recalculation with X-ray data refined to the present limits of performance corroborates the negativity of the rotational strength, but now the most important contributions are due to the peptide bonds formerly neglected. Also for the 2.5 A coordinates it is learned that in contrast to earlier expectation the influence of the backbone in this hemoglobin is rather strong. A substantial contribution is further obtained for the perturbation by one of the propionic acid carboxylate groups of the heme. Perspectives and problems of the approach are outlined.

Amino Acids↗
PubMed1979

[The use of drugs in animal breeding, viewed in the light of the quality of the finished animal product (author's transl)].

In view of the export of foods of animal origin by the Netherlands, it is essential: --to provide guarantees that these finished products shall be free from veterinary drug residues or that any residues shall not be in excess of fixed tolerance levels; --also to adjust legislation concerning the permissibility and use of veterinary drugs and feed additives to factors stimulating the transfer to finished animal products. Adequate methods of investigation will have to be developed; --to perform adequate tests for residues of groups of veterinary drugs on inspecting finished products of animal origin. When these residues are in excess of permissible levels, stock farmers should be prosecuted for possible improper use and the product in question should be condemned; --closely to follow developments in countries to which these products are being exported and to base policies on these developments; --to achieve a high degree of harmonization between legislation concerning veterinary drugs and criteria of investigation.

Animal Feed↗
PubMed2026

Blue light therapy delivered through light glasses improves sleep quality and daytime sleepiness in Parkinson's disease: A randomized trial.

BackgroundSleep disturbances, including excessive daytime sleepiness (EDS) and fragmented nocturnal sleep, are common in Parkinson's disease (PD) and significantly reduce quality of life. This pilot study evaluated the efficacy of a novel approach using blue light, delivered via dedicated glasses with integrated LED lights, to improve sleep and non-motor symptoms.MethodsRandomised, placebo-controlled, single-blind pilot study with a 2-week light intervention. Participants were assessed at baseline, two weeks, and five weeks. The study was designed to evaluate between- and within-group changes. Participants were randomly allocated to receive blue light therapy (n&#x2009;=&#x2009;15) or red light placebo (n&#x2009;=&#x2009;15), delivered via LED-integrated glasses for one hour, twice daily, given for a 2-week period. Primary outcome was improvement in sleep quality, assessed via the Pittsburgh Sleep Quality Index. Secondary outcomes included diary-based sleep outcomes, excessive daytime sleepiness, mood, anxiety, and motor symptoms.ResultsThere was a significant group&#x2009;&#xd7;&#x2009;time effect with blue light therapy leading to better Pittsburgh Sleep Quality Index scores (p&#x2009;=&#x2009;0.021). Between-group analyses showed that at two weeks a trend toward significance was observed (p&#x2009;=&#x2009;0.065), while sleep quality significantly improved at five weeks compared to placebo (p&#x2009;=&#x2009;0.029) with a large effect size (0.896). Excessive sleepiness improved in the blue light group (p&#x2009;<&#x2009;0.001), with a reduction in clinically relevant sleepiness from 50.0% to 6.7% (p&#x2009;=&#x2009;0.005).ConclusionsBlue light therapy delivered through dedicated glasses appeared to show an improvement in sleep quality and daytime sleepiness in individuals with PD. Blue light therapy offers a promising alternative to traditional light therapy utilising lower light intensities and eliminating the need for light boxes.

Aged↗
PubMed2006

Light field and crosshair quality assurance test using a simple lens system.

We describe here a simple lens system to test the positioning of the field light source and mylar crosshair for radiation therapy linear accelerators. Ideally the light source for the field light and the crosshair should be centered on the axis of rotation of the collimator. The traditional method for testing this coincidence uses the shadow of the crosshair caused by the field light source. The shadow of the crosshair is dependent on the position of both the field light source and mylar crosshair. Geometrically it is possible for the field light source and the mylar crosshair to be off the axis of rotation of the collimator and still cause the shadow of the crosshair to be on the axis of rotation at some distance. Using a lens system the motion of the field light source and crosshair can be observed in sharp focus independently of one another as the collimator is rotated.

Equipment Design↗
PubMed2006

Effects of constant, 9 and 16-h light cycles on sperm quality, semen storage ability and motile sperm subpopulations structure of boar semen.

This study was performed to test the effect that two separate, daily, constant-light regimes of both 9 and 16 h could have on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure and the ability of its conservation at 16 degrees C. Results show that both luminous regimes have slight, specific effects on the main parameters of boar-semen quality analysis, as well as on the motile sperm subpopulations structure. Furthermore, the conservation ability at 16 degrees C of boar semen was not significantly different between both photoperiods. When a temporal study was performed, results showed that semen quality and motility parameter changes were stabilized at nearly constant values from the second month of the study to the last month in both luminous regimes, indicating a rapid light-related effect on testicular function. Our results indicate that light regimes oscillating from 9 h daily to 16 h daily are of little importance in the control of boar-semen quality in a farming environment.

Animals↗
PubMed1994

[Asthenoptic complaints in conjunction with illumination by gas discharge lamps].

Asthenopic complaints frequently occur when visual requirements are high in conjunction with illumination by gas discharge lamps. Four causes should be considered: level of the vision task, quality of light (spectral distribution, fluorescent flicker), quality of illumination, individual characteristics of the affected subject. Of 3000 patients, 58% had asthenopic complaints when exposed to gas discharge lamps. The number of females was twice that of males. The subjects affected were predominantly women, aged 20-30 years, who exhibited autonomic lability. Also, they showed reduced concentration power, diminished binocular and stereo vision, and more than normal photic driving findings in the EEG. Fluorescent flicker exerted no influence on elementary visual power, concentration power visuomotor performance, or optical reaction time. It did have an effect on dynamic visual acuity, flicker frequency, blinking rate, and the demands experienced. Fluorescent flicker should be reduced, e.g., by three-phase connection or electronic ballasts. Correcting the binocular vision and reducing the individual glare sensitivity are approaches indicated for individual therapy.

Adult↗
PubMed2006

Cimicifuga species identification by high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection for quality control of black cohosh products.

Black cohosh has become one of the most important herbal products in the US dietary supplements market. It is manufactured from roots and rhizomes of Cimicifuga racemosa (Ranunculaceae). Botanical identification of the raw starting material is a key step in the quality control of black cohosh preparations. The present report summarizes a fingerprinting approach based on high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection (HPLC-PDA/MS/ELSD) that has been developed and validated using a total of 10 Cimicifuga species. These include three North American species, Cimicifuga racemosa, Cimicifuga americana, Cimicifuga rubifolia, and seven Asian species, Cimicifuga acerina, Cimicifuga biternat, Cimicifuga dahurica, Cimicifuga heracleifolia, Cimicifuga japonica, Cimicifuga foetida, and Cimicifuga simplex. The chemotaxonomic distinctiveness of the HPLC fingerprints allows identification of all 10 Cimicifuga species. The triterpene glycoside cimigenol-3-O-arabinoside (3), cimifugin (12), and cimifugin-3-O-glucoside (18) were determined to be suitable species-specific markers for the distinction of C. racemosa from the other Cimicifuga species. In addition to identification, the fingerprint method provided insight into chemical interconversion processes occurring between the diverse triterpene glycosides contained in black cohosh. The reported method has proven its usefulness in the botanical standardization and quality control of black cohosh products.

Chromatography, High Pressure Liquid↗
PubMed1998

Blister artifact formation due to organic solvent effects on Spurr's epoxy resin semithin sections.

Wrinkles and air bubble artifacts may occur when preparing slides of semithin sections (0.5 microm) from blocks embedded in different resins. More than aesthetically annoying, wrinkles and air bubble artifacts may prohibit study of small structures. Present observations suggest that organic solvent based mounting media may interact with the resin of the section. This sometimes causes wrinkles and air bubble artifacts in the sections that degrade the quality of light microscope images. We compared the quality of semithin sections of several tissues in different resins using various types of mounting media. We observed that sections from Spurr's resin have many more artifacts. In particular, small, 2-10 microm round or oblong blister-like artifacts often plague our Spurr's resin sections. We demonstrate that Spurr's resin sections react with toluene and xylene in organic solvent based mounting media forming blisters, while sections from Araldite and L. R. White do not. We suggest combinations of embedding and mounting media for successful preparation of semithin sections for light microscopy without wrinkles, blisters, or air bubble artifacts.

Animals↗