Effects of Cage Position and Light Transmission on Home Cage Activity and Circadian Entrainment in Mice

Light is known to exert powerful effects on behavior and physiology, including upon the amount and distribution of activity across the day/night cycle. Here we use home cage activity monitoring to measure the effect of differences in home cage light spectrum and intensity on key circadian activity parameters in mice. Due to the relative positioning of any individually ventilated cage (IVC) with regard to the animal facility lighting, notable differences in light intensity occur across the IVC rack. Although all mice were found to be entrained, significant differences in the timing of activity onset and differences in activity levels were found between mice housed in standard versus red filtering cages. Furthermore, by calculating the effective irradiance based upon the known mouse photopigments, a significant relationship between light intensity and key circadian parameters are shown. Perhaps unsurprisingly given the important role of the circadian photopigment melanopsin in circadian entrainment, melanopic illuminance is shown to correlate more strongly with key circadian activity parameters than photopic lux. Collectively, our results suggest that differences in light intensity may reflect an uncharacterized source of variation in laboratory rodent research, with potential consequences for reproducibility. Room design and layout vary within and between facilities, and caging design and lighting location relative to cage position can be highly variable. We suggest that cage position should be factored into experimental design, and wherever possible, experimental lighting conditions should be characterized as a way of accounting for this source of variation.

Light Scattering by a Subwavelength Plasmonic Array: Anisotropic Model

We calculate the light transmission by a subwavelength plasmonic array using the boundary element method for parallel cylinders with different cross-sections: circular or elliptic with axis ratio 4:1. We demonstrate that plasmonic resonance is sharper for the case of horizontal ellipses. This structure is susceptible to refractive index variations in the media since the high derivatives of reflection and transmission coefficients are near the angle of total internal reflection. To obtain an approximate analytical expression, we used the model of a metallic layer. We explore the “sandwich” structure with an anisotropic film between two dielectrics and demonstrate its quantitative agreement with numerical results.

Light Transmission of Various Aesthetic Posts at Different Depths and Its Effect on Push-Out Bond Strength, Microhardness of Luting Cement

Background and Objectives: One requirement for the cemented post is the light transmittance on its entire length up to the deepest portion of a root canal to ensure the complete polymerization of resin cement. This study aimed to determine the light transmission ability in different aesthetic posts at different depths and its effect on the push-out bond strength and microhardness of luting cement at the corresponding interface. Materials and Methods: Twenty endodontic posts from glass fiber posts (GFP), zirconia ceramic posts (ZCP), and highly translucent zirconium oxide posts (HTZP) were sequentially sectioned into 12.8 and 4 mm lengths after recording the light intensity using a dental radiometer. Sixty single rooted premolar teeth root canals were treated and implanted vertically in a resin block. The post space was prepared and cemented with GFP, ZCP, and HTZP posts with twenty samples each. The root portion of teeth samples were sectioned into cervical, middle, and apical portion. A universal testing machine was utilized for the push-out bond strength test for the first ten samples from each group. The remaining ten samples from each group were used for the microhardness test using a micro-indenter instrument. The data were statistically analyzed using one-way Analysis of variance and Tukey HSD tests at p < 0.05. Results: The GFP endodontic postpresented with significant highest light translucency compared to HTZP, which was significantly higher than ZCP. GFP posts showed significantly higher bond strength per unit area compared to ZCP at analogous cross sections. The hardness of luting cement was also significantly higher amongst all tested endodontic posts. Conclusions: GFP high light translucency enhanced the curing of the luting resin cement that resulted in harder cement and a stronger bond supported by hardness and push-out tests. These findings suggest that GFP is preferred to be used with light-cured luting cements for restoration of endodontically treated teeth.

Identification of internal cracks in corn seed using convolutional neural networks

The identification of seed quality is very important for which the quality of seed is crucial to the yield and quality of crops. There are two main problems with the acquisition and identification of cracks inside corn seed. One is that most of the methods of near-infrared spectroscopy or X-ray are used to obtain images of cracks inside the seed, the acquisition equipment is expensive and the operation is complicated. The other is the identification of crack images, and the traditional image processing method is usually used which requires professionals to design different model parameters each time, resulting in poor model robustness and low model accuracy. In this study, we originally proposed a simple but effective method to obtain the picture of corn seed internal cracks, which is combined with visible light transmission and ordinary camera acquisition method. We also proposed using the transfer learning methods not only solving the problem of the small scale of our corn seed internal cracks dataset but also avoiding extracting features manually. Our proposed method achieved a promising result, which is able to correctly identify the cracked and intact corn seed 100% in our training stage and testing stage.

Egg Yolk Oil as a Plasticizer for Polylactic Acid Films

Polylactic acid (PLA) is known to be one of the most extensively used biodegradable thermoplastic polyesters, with the potential to replace conventional petroleum-based packaging materials; however, the low flexibility of films prepared using PLA has limited the applications of this biopolymer. In this study, in order to improve the mechanical properties of PLA films and to provide them with antioxidant properties, egg yolk oil was used as a biobased plasticizer. For this purpose, PLA films with increasing concentrations of egg yolk oil were prepared and the effects of this oil on the light transmission, transparency, colour, water vapour permeability, solubility, antioxidant activity and mechanical properties of the films were characterized. In addition, electron microscopy of the structure of the transverse section of the films was also performed. Results showed that the formulations with higher concentrations of egg yolk oil increased the films’ elasticity, and their light barrier and antioxidant properties. Finally, in order to test the films as a packaging material for food applications, extra virgin olive oil and resveratrol, both photosensitive compounds, were packed and exposed to ambient light. Overall, the results show the potential of egg yolk oil as an environmentally friendly plasticizer that can improve the flexibility of PLA films and provide them with additional photoprotective properties.

Interrelation between Spectral Online Monitoring and Postoperative T1-Weighted MRI in Interstitial Photodynamic Therapy of Malignant Gliomas

In a former study, interstitial photodynamic therapy (iPDT) was performed on patients suffering from newly diagnosed glioblastoma (n = 11; 8/3 male/female; median age: 68, range: 40–76). The procedure includes the application of 5-ALA to selectively metabolize protoporphyrin IX (PpIX) in tumor cells and illumination utilizing interstitially positioned optical cylindrical diffuser fibers (CDF) (2–10 CDFs, 2–3 cm diffusor length, 200 mW/cm, 635 nm, 60 min irradiation). Intraoperative spectral online monitoring (SOM) was employed to monitor treatment light transmission and PpIX fluorescence during iPDT. MRI was used for treatment planning and outcome assessment. Case-dependent observations included intraoperative reduction of treatment light transmission and local intrinsic T1 hyperintensity in non-contrast-enhanced T1-weighted MRI acquired within one day after iPDT. Intrinsic T1 hyperintensity was observed and found to be associated with the treatment volume, which indicates the presence of methemoglobin, possibly induced by iPDT. Based on SOM data, the optical absorption coefficient and its change during iPDT were estimated for the target tissue volumes interjacent between evaluable CDF-pairs at the treatment wavelength of 635 nm. By spatial comparison and statistical analysis, it was found that observed increases of the absorption coefficient during iPDT were larger in or near regions of intrinsic T1 hyperintensity (p = 0.003). In cases where PpIX-fluorescence was undetectable before iPDT, the increase in optical absorption and intrinsic T1 hyperintensity tended to be less. The observations are consistent with in vitro experiments and indicate PDT-induced deoxygenation of hemoglobin and methemoglobin formation. Further investigations are needed to provide more data on the time course of the observed changes, thus paving the way for optimized iPDT irradiation protocols.

Characterization of GPVI- or GPVI-CD39-Coated Nanoparticles and Their Impact on In Vitro Thrombus Formation

Traditional antithrombotic agents commonly share a therapy-limiting side effect, as they increase the overall systemic bleeding risk. A novel approach for targeted antithrombotic therapy is nanoparticles. In other therapeutic fields, nanoparticles have enabled site-specific delivery with low levels of toxicity and side effects. Here, we paired nanotechnology with an established dimeric glycoprotein VI-Fc (GPVI-Fc) and a GPVI-CD39 fusion protein, thereby combining site-specific delivery and new antithrombotic drugs. Poly(lactic-co-glycolic acid) (PLGA) nanoparticles, NP-BSA, NP-GPVI and NP-GPVI-CD39 were characterized through electron microscopy, atomic force measurements and flow cytometry. Light transmission aggregometry enabled analysis of platelet aggregation. Thrombus formation was observed through flow chamber experiments. NP-GPVI and NP-GPVI-CD39 displayed a characteristic surface coating pattern. Fluorescence properties were identical amongst all samples. NP-GPVI and NP-GPVI-CD39 significantly impaired platelet aggregation. Thrombus formation was significantly impaired by NP-GPVI and was particularly impaired by NP-GPVI-CD39. The receptor-coated nanoparticles NP-GPVI and the bifunctional molecule NP-GPVI-CD39 demonstrated significant inhibition of in vitro thrombus formation. Consequently, the nanoparticle-mediated antithrombotic effect of GPVI-Fc, as well as GPVI-CD39, and an additive impact of CD39 was confirmed. In conclusion, NP-GPVI and NP-GPVI-CD39 may serve as a promising foundation for a novel therapeutic approach regarding targeted antithrombotic therapy.

Mimicry can drive convergence in structural and light transmission features of transparent wings in Lepidoptera

Müllerian mimicry is a positive interspecific interaction, whereby co-occurring defended prey species share a common aposematic signal. In Lepidoptera, aposematic species typically harbour conspicuous opaque wing colour patterns with convergent optical properties among co-mimetic species. Surprisingly, some aposematic mimetic species have partially transparent wings, raising the questions of whether optical properties of transparent patches are also convergent, and of how transparency is achieved. Here, we conducted a comparative study of wing optics, micro and nanostructures in neotropical mimetic clearwing Lepidoptera, using spectrophotometry and microscopy imaging. We show that transparency, as perceived by predators, is convergent among co-mimics in some mimicry rings. Underlying micro- and nanostructures are also sometimes convergent despite a large structural diversity. We reveal that while transparency is primarily produced by microstructure modifications, nanostructures largely influence light transmission, potentially enabling additional fine-tuning in transmission properties. This study shows that transparency might not only enable camouflage but can also be part of aposematic signals.

Investigating homeopathic preparations with light spectroscopy

Background Several series of experiments from our research group have shown ultraviolet (UV) light transmission of homeopathic preparations to slightly but significantly differ from controls. We now investigated whether visible and near infrared spectroscopy were also useful for exploring properties of homeopathic preparations. Materials and methods Homeopathic preparations of copper sulfate (CuSO4), hypericum and sulfur (S8) were produced in 30 sequential steps of 1:100 dilutions (c-preparations). As controls, succussed potentization medium was used. Transmission of the samples from 190-1100nm was measured 4 times on 5 days with a double beam Shimadzu UV PC 1601 spectrophotometer. To correct for the daily variations of the spectrophotometer, transmission of the samples at each nm was divided by the average transmission of the controls. Median transmissions of the samples were calculated for the ranges of 190-340nm (near and middle UV), 340-640nm (visible light without red), and 640-1100nm (red and near infrared). Differences in the median transmission between potency levels from 6c to 30c were determined using Kruskal-Wallis and Jonckheere-Terpstra tests. Results Differences in transmissions of the various potency levels were more pronounced in the UV range than in the visible or red/near infrared range. The Kruskal-Wallis test revealed significant differences for homeopathic preparations of CuSO4, hypericum and S8 in the UV range (p=0.032, 0.008, 0.009, respectively) and of S8 in the visible range (p=0.026). Jonckheere's test showed a tendency towards ascending medians with ascending potency levels for CuSO4 in the UV range (p=0.080). Significant trends were revealed for hypericum in the visible range (p=0.042, descending medians) and S8 in the UV range (p=0.015, ascending medians). Conclusion UV spectroscopy seemed to be more suitable for investigating homeopathic preparations than visible or near infrared spectroscopy, since differences in transmission were more pronounced in the UV range.