Fiber-optic light guides as secondary sources of light for hen keeping in cage batteries

The method of local illumination of cage batteries with LED lamps, previously developed by us, made it possible to increase the livability and productivity of hens in comparison with the traditional method. In this case, the placement of low-power LED sources directly in each cage requires a large number of rather complex electronic devices across the whole metal structure of the cage battery and extended power transmission lines. This work compares the efficiency of local LED lighting and fiber-optic light guides when keeping hens of the productive flocks of cross SP-789 in traditional cages. The 120-day-old hens were divided by the method of analogs in 2 groups of 100 heads. In the control group, LED lamps were used for local illumination of hens, and in the experimental group, fiber-optic light guides were used with LEDs as the primary source of illumination. The color temperature of light-emitting diodes was 3000 K. Up to 260 days of age, hens were kept in triple-tiered cage batteries, 5 animals per cage. The results of the study showed that in the control and experimental groups, the livability of the livestock was 95.0 and 99.0%, the egg production per initial hen was 99.2 and 102.5 pieces. The weight of eggs was 57.9 and 58.3 g, the yield of the egg weight per initial hen was 5.81 and 5.98 kg, feed consumption for 10 eggs and 1 kg of egg weight were 1.37, 2.35 and 1.30, 2.23 kg, respectively, without significant changes in the morphological and chemical qualities of eggs.

Rotlicht-gesteuerter viraler Gentransfer mit Einzelzellauflösung

Available methods for efficient gene transfer into user-selected or even single cells suffer from high invasiveness or the need for complicated equipment. Here, we present a technology for the light-guided transduction of native cell lines and primary cells by adeno-associated viral (AAV) vectors. We demonstrate the spatially resolved transduction of different cells with different genes within one culture and the selective transduction of single cells by local illumination.

Photodynamic Therapy: Targeting Cancer Biomarkers for the Treatment of Cancers

Photodynamic therapy (PDT) is a well-documented therapy that has emerged as an effective treatment modality of cancers. PDT utilizes harmless light to activate non- or minimally toxic photosensitizers to generate cytotoxic species for malignant cell eradication. Compared with conventional chemotherapy and radiotherapy, PDT is appealing by virtue of the minimal invasiveness, its safety, as well as its selectivity, and the fact that it can induce an immune response. Although local illumination of the cancer lesions renders intrinsic selectivity of PDT, most photosensitizers used in PDT do not display significant tumor tissue selectivity. There is a need for targeted delivery of photosensitizers. The molecular identification of cancer antigens has opened new possibilities for the development of effective targeted therapy for cancer patients. This review provides a brief overview of recent achievements of targeted delivery of photosensitizers to cancer cells by targeting well-established cancer biomarkers. Overall, targeted PDT offers enhanced intracellular accumulation of the photosensitizer, leading to improved PDT efficacy and reduced toxicity to normal tissues.

Evaluation and Normalization of Topographic Effects on Vegetation Indices

The normalization of topographic effects on vegetation indices (VIs) is a prerequisite for their proper use in mountainous areas. We assessed the topographic effects on the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI), the soil adjusted vegetation index (SAVI), and the near-infrared reflectance of terrestrial vegetation (NIRv) calculated from Sentinel-2. The evaluation was based on two criteria: the correlation with local illumination condition and the dependence on aspect. Results show that topographic effects can be neglected for the NDVI, while they heavily influence the SAVI, EVI, and NIRv: the local illumination condition explains 19.85%, 25.37%, and 26.69% of the variation of the SAVI, EVI, and NIRv, respectively, and the coefficients of variation across different aspects are, respectively, 8.13%, 10.46%, and 14.07%. We demonstrated the applicability of existing correction methods, including statistical-empirical (SE), sun-canopy-sensor with C-correction (SCS + C), and path length correction (PLC), dedicatedly designed for reflectance, to normalize topographic effects on VIs. Our study will benefit vegetation monitoring with VIs over mountainous areas.

Underwater caustics disrupt prey detection by a reef fish

Natural habitats contain dynamic elements, such as varying local illumination. Can such features mitigate the salience of organism movement? Dynamic illumination is particularly prevalent in coral reefs, where patterns known as ‘water caustics’ play chaotically in the shallows. In behavioural experiments with a wild-caught reef fish, the Picasso triggerfish ( Rhinecanthus aculeatus ), we demonstrate that the presence of dynamic water caustics negatively affects the detection of moving prey items, as measured by attack latency, relative to static water caustic controls. Manipulating two further features of water caustics (sharpness and scale) implies that the masking effect should be most effective in shallow water: scenes with fine scale and sharp water caustics induce the longest attack latencies. Due to the direct impact upon foraging efficiency, we expect the presence of dynamic water caustics to influence decisions about habitat choice and foraging by wild prey and predators.

Flexible Conductive Polymer Film Grafted with Azo-Moieties and Patterned by Light Illumination with Anisotropic Conductivity

In this work, we present the method for the creation of an anisotropic electric pattern on thin poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) films through PSS grafting by azo-containing moieties followed by light-induced polymers redistribution. Thin PEDOT:PSS films were deposited on the flexible and biodegradable polylactic acid (PLLA) substrates. The light-sensitive azo-groups were grafted to PSS using the diazonium chemistry followed by annealing in methanol. Local illumination of azo-grafted PEDOT:PSS films through the lithographic mask led to the conversion of azo-moieties in Z-configuration and further creation of the lateral gradient of azo-isomers along the film surface. The concentration gradient led to the migration of PSS away from the illuminated area, increasing the PEDOT chains’ concentration and the corresponding increase of local electrical conductivity in the illuminated place. Utilization of mask with linear pattern results in the appearance of conductive PEDOT-rich and non-conductive PSS-rich lines on the film surface, and final, lateral anisotropy of electric properties. Our work gives an optical lithography-based alternative to common methods for the creation of anisotropic electric properties, based on the spatial confinement of conductive polymer structures or their mechanical strains.

Light-Addressable Electrochemical Sensing of Dopamine Using on N-Silicon/gold Schottky Junctions

Here, we report the use of semiconductor/metal (Schottky) junctions as light-addressable electrochemical sensors (LAES). We employ an n-Si/Au Schottky junction prepared by electrodeposition of Au nanoparticles (NPs) on a freshly etched n-Si photoelectrode. The sensors demonstrate near reversible electrochemical behavior for the oxidation of ferrocene methanol and potassium ferrocyanide. Moreover, n-Si/Au LAES were stable for 1000 cyclic voltammetry cycles in an aqueous electrolyte – even though the n-Si surface was only partially covered with Au NPs. We also challenged the LAES to detect the neurotransmitter dopamine and found that the sensors were quantitative over the range from 15-500 µM in buffer. We used local illumination to generate a virtual array of electrochemical sensors for dopamine as a strategy for circumventing sensor fouling.

Light-Addressable Electrochemical Sensing of Dopamine Using on N-Silicon/gold Schottky Junctions

Here, we report the use of semiconductor/metal (Schottky) junctions as light-addressable electrochemical sensors (LAES). We employ an n-Si/Au Schottky junction prepared by electrodeposition of Au nanoparticles (NPs) on a freshly etched n-Si photoelectrode. The sensors demonstrate near reversible electrochemical behavior for the oxidation of ferrocene methanol and potassium ferrocyanide. Moreover, n-Si/Au LAES were stable for 1000 cyclic voltammetry cycles in an aqueous electrolyte – even though the n-Si surface was only partially covered with Au NPs. We also challenged the LAES to detect the neurotransmitter dopamine and found that the sensors were quantitative over the range from 15-500 µM in buffer. We used local illumination to generate a virtual array of electrochemical sensors for dopamine as a strategy for circumventing sensor fouling.

2160Continuous shock-free termination of atrial fibrillation by local optogenetic therapy and arrhythmia-triggered activation of an implanted light source

Background Maintenance of sinus rhythm is the primary therapeutic goal for symptomatic atrial fibrillation (AF) patients but remains difficult to achieve because of suboptimal treatment options. While being effective in detecting and terminating AF, the widespread use of implantable atrial defibrillators is limited due to patients intolerance to repeated shocks. The negative adverse effects of electroshock therapy can hypothetically be overcome by allowing the heart itself to produce the electric current required for arrhythmia termination. As a result, the effector function of an electrical defibrillator would be provided by the heart itself, and therefore no longer rely on electronics, but on bioelectricity instead. Purpose To develop a hybrid bio-electronic system for automated and acute shock-free AF treatment. Methods To equip the heart with the effector function of the envisioned AF termination system, adeno-associated virus (AAV) vectors encoding red-activatable channelrhodopsin (ReaChR) (n=12) or citrine (n=4) were delivered locally to the right atrium (RA) of adult Wistar rats by gene painting. Four to 8 weeks later, AF was induced in vivo by atrial burst pacing after carbachol administration, followed by programmed local illumination of the RA by an implanted intrathoracic LED device whose activation was automatically regulated by an electrocardiogram (ECG)-based cardiac rhythm monitor. Results Gene painting of the RA resulted in transmural transduction of right atrial myocytes (78±6%) with minimum transgene expression of the left atrium and ventricles (6±2% and <0.5%, respectively). Electrophysiological assessments revealed no significant differences in ECG characteristics, atrial action potential duration and conduction velocity when compared to baseline or citrine control animals. Feasibility of optical AF termination was first assessed in an open-chest rat model, showing that a single 470-nm light pulse (3.5 mW/mm2, 1000 ms) efficiently terminated AF in all ReaChR-expressing rats with an average termination efficacy of 94±3% (n=12) vs. 3±3% (n=4) in citrine-expressing control animals (p<0.01). AF termination efficacy remained superb following automated detection and termination of AF by ECG-triggered activation of the implanted intra-thoracic LED in closed-chest ReaChR-expressing rats (96±4%), n=4), whereas none of the AF episodes were terminated in control rats (0%, n=4) (p<0.01). No bradycardias or other arrhythmias were observed following optical AF termination. Conclusions By using a hybrid bio-electronic approach to modulate cardiac excitability, our study delivers proof that AF can be detected and terminated automatically in a safe, effective and repetitive, yet shock-free manner. These findings may create the basis for the development of pain-free device therapy for cardiac arrhythmias, thereby paving the way for ambulatory AF treatment with the perspective to improve patients' prognosis and quality of life. Acknowledgement/Funding NWO Vidi grant (1714336) and ERC Starting Grant (716509) both to D.A.P.