Ultraviolet vision in larval Neogonodactylus oerstedii

Stomatopod crustaceans have among the most complex eyes in the animal kingdom, with up to twelve different color detection channels. The capabilities of these unique eyes include photoreception of ultraviolet (UV) wavelengths (<400 nm). UV vision has been well characterized in adult stomatopods but has not been previously demonstrated in the comparatively simpler larval eye. Larval stomatopod eyes are developmentally distinct from their adult counterpart and have been described as lacking the visual pigment diversity and morphological specializations found in adult eyes. However, recent studies have provided evidence that larval stomatopod eyes are more complex than previously thought and warrant closer investigation. Using electroretinogram recordings in live animals we found physiological evidence of blue and UV sensitive photoreceptors in larvae of the Caribbean stomatopod species Neogonodactylus oerstedii. Transcriptomes of individual larvae were used to identify the expression of three distinct UV opsins transcripts, which may indicate the presence of multiple UV spectral channels. This is the first paper to document UV vision in any larval stomatopod, expanding our understanding of the importance of UV sensitivity in plankton. Similar to adults, larval stomatopod eyes are more complex than expected and contain previously uncharacterized molecular diversity and physiological functions.

Improvement of Porous GaN-Based UV Photodetector with Graphene Cladding

This work presents the role of graphene in improving the performance of a porous GaN-based UV photodetector. The porous GaN-based photodetector, with a mean pore diameter of 35 nm, possessed higher UV sensitivity, about 95% better compared to that of the as-received (non-porous) photodetector. In addition, it exhibits a lower magnitude of leakage current at dark ambient, about 70.9 μA, compared to that of the as-received photodetector with 13.7 mA. However, it is also highly resistive in nature due to the corresponding electrochemical process selectively dissolute doped regions. Herein, two types of graphene, derived from CVD and the electrochemical exfoliation (EC) process, were cladded onto the porous GaN region. The formation of a graphene/porous GaN interface, as evident from the decrease in average distance between defects as determined from Raman spectroscopy, infers better charge accumulation and conductance, which significantly improved UV sensing. While the leakage current shows little improvement, the UV sensitivity was greatly enhanced, by about 460% and 420% for CVD and EC cladded samples. The slight difference between types of graphene was attributed to the coverage area on porous GaN, where CVD-grown graphene tends to be continuous while EC-graphene relies on aggregation to form films.

Semiconductor Materials and Modelling for Solar Cells

The book presents a comprehensive survey about advanced solar cell technologies. Focus is placed on semiconductor materials, solar cell efficiency, improvements in surface recombination velocity, charge density, high ultraviolet (UV) sensitivity, modeling of solar cells etc. The book references 281 original resources with their direct web links for in-depth reading.

Nonperturbative dynamics of (2+1)d ϕ4-theory from Hamiltonian truncation

We use Lightcone Conformal Truncation (LCT)—a version of Hamiltonian truncation — to study the nonperturbative, real-time dynamics of ϕ4-theory in 2+1 dimensions. This theory has UV divergences that need to be regulated. We review how, in a Hamiltonian framework with a total energy cutoff, renormalization is necessarily state-dependent, and UV sensitivity cannot be canceled with standard local operator counter-terms. To overcome this problem, we present a prescription for constructing the appropriate state-dependent counterterms for (2+1)d ϕ4-theory in lightcone quantization. We then use LCT with this counterterm prescription to study ϕ4-theory, focusing on the ℤ2 symmetry-preserving phase. Specifically, we compute the spectrum as a function of the coupling and demonstrate the closing of the mass gap at a (scheme-dependent) critical coupling. We also compute Lorentz-invariant two-point functions, both at generic strong coupling and near the critical point, where we demonstrate IR universality and the vanishing of the trace of the stress tensor.

Laser-Tunable Printed ZnO Nanoparticles for Paper-Based UV Sensors with Reduced Humidity Interference

Development of paper-based sensors that do not suffer with humidity interference is desirable for practical environmental applications. In this work, a laser processing method was reported to effectively modulate the cross-sensitivity to humidity of ZnO-based UV (Ultraviolet) sensors printed on paper substrate. The results reveal that the laser induced zinc oxide (ZnO) surface morphology contributes to the super-hydrophobicity of the printed ZnO nanoparticles, reducing humidity interference while enhancing UV sensitivity. Herein, this conducted research highlights for the first time that laser processing is an attractive choice that reduces the cross-sensitivity to water vapor in the UV sensing response of ZnO-based devices printed on paper, paving the way to low-cost and sophisticated paper-based sensors.

UV Sensitivity of Free and Immobilized on Chitosan Matrix Proteases

UV irradiation is an essential factor in natural and artificial climate in modern environmental conditions, which has a constant effect on living systems. Collagenase, bromelain, ficin, papain (Sigma-Aldrich: St. Louis, MO, USA) and trypsin (MP biomedicals: Santa Ana, CA, USA) were the objects of this study. The substrate for hydrolysis was BSA (Sigma-Aldrich: St. Louis, MO, USA), the carriers for immobilization were chitosans (<100, 200 and 350 kDa) and chitosan succinate (Bioprogress: Shchyolkovo, Russia). The protease immobilization was carried out by the adsorption. The determination of the protein amount in samples and their catalytic activity was carried out by the modified Lowry method. UV irradiation of proteases was performed using doses 151–6040 J/m2. By the degree of photosensitivity, hydrolases can be arranged in the next row: collagenase → bromelain → ficin → papain → trypsin. Adsorption on a chitosan and succinate of chitosan leads to an increase in the stability to ultraviolet light of heterogeneous (immobilized) biocatalysts compared to free enzymes. Photoprotective effect of the chitosan may be due to the following reasons: enzyme interact with the chitosan to form photo resistant complexes; сhitosan screens active free-radicals, preventing the photooxidation of a certain number of amino acids, including the active centers of the studied enzymes under the influence of UV irradiation.