Light Of Specific Wavelength Research Articles

Drought tolerance of faba bean (Vicia faba L.) can be improved by specific LED light wavelengths

A light wavelength affects both plant photomorphogenesis and stress resistance. In this study, the phenotypic plasticity (growth parameters and cuticular waxes) and physiological adaptation (photosynthetic properties and antioxidant enzyme activities) of faba bean subjected to specific LED lights, red, yellow, blue, violet, and white, were analyzed under two water conditions (normal and drought). The plants grown under red and yellow lights possessed the smaller leaf size and the higher leaf relative water content. The blue light had a positive effect on improving stomatal conductance and net photosynthetic rate of faba bean leaves, and the plants grown under the blue light also had higher antioxidant enzyme activities. The blue light also changed the dominant wax component to alkanes and significantly decreased a total wax load under the drought stress, and thus minimized the cuticle transpiration (water loss). The decreased wax deposition and the increase of C31-C33 alkanes abundance in plants grown under the yellow light also resulted in a lower leaf water loss under the drought stress. The red light increased but the violet light did not change the cuticle water loss. These results suggest that plant drought tolerance could be improved by supplementing the blue and yellow lights.

Design of a hybrid plasmonic waveguide device using a trench structure

A hybrid plasmonic waveguide device was designed using a trench structure. This waveguide device was designed to improve the affinity of plasmonic devices with optical circuits by connecting them with traditional waveguide structures. The waveguide device consists of three structural segments, comprising two traditional waveguide sections for input and transmission and a hybrid plasmonic waveguide. The designed waveguide structure was evaluated using numerical analysis techniques such as the finite-difference time-domain method. The device's transmission property affects the interference between the guided light and the surface plasmon polaritons. Controlling the length of the hybrid waveguide device, which is composed of a traditional waveguide coated with a gold layer, allows the transmission intensity of the device to be controlled. The device's transmission characteristic can be controlled based on the relationship between the wavelength of the incident light and the length of the hybrid waveguide device. The device will transmit only specific incident light wavelengths because the length of the hybrid plasmonic waveguide remains constant. The characteristics of this device indicate potential for applications to nanoscale devices, optical integrated circuits and plasmonic sensors.

The impact of coloured filters on the performance of polycrystalline photovoltaic panel in an uncontrolled environment

Photovoltaic modules behave extraordinarily by transforming part of the visible spectrum into electrical energy, and their efficiencies are affected by the nature of radiation (light) reaching them. When light strikes a photovoltaic cell, this light may go through the cell without been absorbed if it is too energetic or if the light possesses low energy it will be absorbed by the cell and cause the electrons to twist and vibrate in their bonds without dislodging them, hence causing the cell to heat up which ultimately leads to a decrease in its overall efficiency. This study is aimed to investigate how photovoltaics respond to different wavelengths of light. For the study to achieve its aim, colour filters were used to ensure that only a particular wavelength of light reaches the photovoltaic module at a time. In the process of collecting data from the solar panel, the solar panel was placed horizontally flat on a platform one meter above sea level facing the sun. Data was first obtained from the solar panel without the filters and after that with the filters placed one at a time and data collected accordingly. The amount of solar power and solar flux anytime a different colour filter was placed on the solar panel were measured. Among the coloured filter used yellow produced the highest efficiency, while blue produced the least efficiency. However, the solar panel was still more efficient when exposed to the natural spectrum.

<p>Enhanced Efficacy of Photodynamic Therapy by Coupling a Cell-Penetrating Peptide with Methylene Blue</p>

IntroductionPhotodynamic therapy (PDT), which induces tissue damage by exposing tissue to a specific wavelength of light in the presence of a photosensitizer and oxygen, is a promising alternative treatment that could be used as an adjunct to chemotherapy and surgery in oncology. Cell-penetrating peptides (CPPs) with high arginine content, such as protamine, have membrane translocation and lysosome localization activities. They have been used in an extensive range of drug delivery applications.MethodsWe conjugated cell-penetrating peptides (CPPs) with methylene blue (MB) and then purification by FPLC. Synthesis structure was characterized by the absorbance spectrum, FPLC, Maldi-TOF, and then evaluated cell viability by cytotoxicity assay after photodynamic therapy (PDT) assay. An uptake imaging assay was used to determine the sites of MB and MB-Pro in subcellular compartments.ResultsIn vitro assays showed that MB-Pro has more efficient photodynamic activities than MB alone for the colon cancer cells, owing to lysosome rupture causing the rapid necrotic cell death. In this study, we coupled protamine with MB for high efficacy PDT. The conjugates localized in the lysosomes and enhanced the efficiency of PDT by inducing necrotic cell death, whereas PDT with non-coupled MB resulted in only apoptotic processes.DiscussionOur research aimed to enhance PDT by engineering the photosensitizers using CPPs coupled with methylene blue (MB). MB alone permeates through the cell membrane and distributes into the cytoplasm, whereas coupling of MB dye with CPPs localizes the MB through an endocytic mechanism to a specific organelle where the localized conjugates enhance the generation of reactive oxygen species (ROS) and induce cell damage.

P‐224: Late‐News‐Poster: High‐Transmittance ADS TV Technology with Negative Liquid Crystal Based on Rubbing Process

This paper described the key technology of ADS TV with negative liquid crystal based on rubbing process. ADS technology has been widely used in all size LCD because of its outstanding features like high transmittance, wide view, and weak color shift With negative liquid crystal, it can effectively improve the transmittance, color shift caused by the pre‐tilt angle of LC and contrast ratio. Negative liquid crystal with optical alignment process has been well developed, but it cannot be applied to high generation such as G10.5 TFT‐LCD lines because of the risk of the uniformity of specific wavelengths of light, and the limitation of OA equipment. The rubbing PI materials and negative liquid crystal materials has been tested. Evaluations give a better match between them. The ADS TFT‐LCD's reliability properties such as image sticking are improved dramatically. At the same time, the transmittance improved by 8% and contrast ratio is up to 2100 based on UHD TV and 1700 based on 8K TV. The maximum △UV of the color shift drops from 0.05 to 0.03 at the range of 180°, which greatly improve the performance of large size products. In view of the above improvements, the performance BOE's of ADS Pro products has been greatly improved.

Dichroic Sb2O3/Ag/Sb2O3 Electrodes for Colorful Semitransparent Organic Solar Cells

The pace of advancement and increasing power conversion efficiencies (PCEs) have provided the possibility for organic solar cells (OSCs) to be commercialized in a variety of applications, including semitransparent photovoltaics. The application of dielectric–metal–dielectric (DMD) transparent electrodes to OSCs is an effective way to achieve semitransparent OSCs with different colors. Herein, a DMD multilayer structure based on two Sb2O3 layers and silver (Ag) thin films as the top electrode is introduced. An ultrathin Sb2O3 layer is deposited between the electron transport layer and the Ag film as a bottom layer for the Sb2O3/Ag/Sb2O3 electrode; this layer inhibits Ag atom diffusion and aggregation, which leads to uniform formation of ultrathin Ag films. The thickness of the middle metal layer influences fill factor and short‐circuit current density values, which correlate well with device resistance and light reflection. For the top Sb2O3 layer, the thickness allows the selective transmittance of specific wavelengths of visible light while reflecting wavelengths that are not transmitted, creating a dichroic effect. OSCs are successfully fabricated using three kinds of colorful active layers in conjunction with Sb2O3/Ag/Sb2O3 electrodes, resulting in vividly colored devices with PCE of 6.33–7.88% and average visible transmittances of 23–30%.

Photodynamic therapy using topical toluidine blue for the treatment of oral leukoplakia: A prospective case series.

Photodynamic therapy (PDT) is a minimally invasive method for the treatment of oral leukoplakia (OL) through the activation of a photosensitizer, after exposure to a specific wavelength light source. To investigate the effectiveness of toluidine blue as topical photosensitizer. Eleven patients participated in this study; fifteen oral leukoplakia lesions were treated, in several sessions, with 2.5 % toluidine blue and an LED source of 630 nm wavelength. Patients were evaluated at baseline (t0), at the end of treatment cycles (t1) and one year from the end of treatment (t2). All the treated sites were photographed at each visit. Images were processed with ImageJ 1.52 software in order to obtain the areas (mm2) of the treated lesions. Comparison between data at different follow-up was performed using a paired T-test. At t1, complete response was obtained in six lesions, partial response in seven lesions while only two lesions showed no response. At t2, a further improvement was observed in two patients. The analysis of the areas showed significant reduction of the lesion size from t0 to t1 (p = 0.003), and from t1 to t2 (p = 0.01). Toluidine blue appears to be a promising photosensitizer in the photodynamic therapy of oral leukoplakia.

Agranulocyte & neutrophil nucleus enhancement through 510nm wavelength of light

Enhanced features can be easily segmented and used for classification algorithms. Light wavelength of 510nm is used as illumination source for bright field microscope. This specific wavelength of light enhances nucleus, granules in White blood Cells (WBCs). Eosinophil and basophil has coarse granules which also get enhanced hence nucleus segmentation gets difficult. This method is effective in enhancing nucleus of agranulocytes viz. Lymphocyte, Monocyte and Neutrophil of normal person. This modification in image acquisition of pathological images will further help in quick segmentation of features.

NIMH Director Describes Ways to Better Target Therapy

Back to table of contents Previous article Next article Clinical & ResearchFull AccessNIMH Director Describes Ways to Better Target TherapyNick ZagorskiNick ZagorskiSearch for more papers by this authorPublished Online:2 Jun 2020https://doi.org/10.1176/appi.pn.2020.6a36AbstractMapping brain regions linked to discrete aspects of mood along with the neural circuits connecting them may lead to more precise treatments for psychiatric disorders.More precise psychiatric treatment may rest on the ability of researchers to understand and manipulate the brain centers and circuits that underlie discrete components of behavior, says NIMH Director Joshua Gordon, M.D., Ph.D.Chia-Chi Charlie ChangResearch into neural circuits and brain phenotyping may herald new breakthroughs in psychiatry, said National Institute of Mental Health (NIMH) Director Joshua Gordon, M.D., Ph.D., during his presentation at APA’s Spring Highlights Meeting.“We have made a lot of progress in understanding how different parts of the brain communicate to influence human behavior,” Gordon said. “We have also developed new tools that we can use to manipulate these different brain regions in laboratory models.”Gordon cited some recent studies done at his NIMH lab using specially designed viruses to target a circuit bridging the hippocampus and prefrontal cortex that is believed to be a key conduit for anxiety-like behaviors. These viruses had special light-sensitive proteins, enabling researchers to turn the circuit on or off using light energy (a research tool known as optogenetics). Using specific wavelengths of light, Gordon’s lab was able to make mice more, or less, afraid of open spaces.“What that means is we can cure, or cause, anxiety in mice,” Gordon said. Other research groups have also used optogenetics to manipulate behaviors such as binge drinking.Gordon said studies like these may one day lead to more targeted therapies for mood disorders. He said it’s also possible that technologies such as optogenetics can be adapted to be safe and effective in humans.In addition to neural circuit research, Gordon highlighted a second long-term research area that NIMH is considering a priority: using computational biology to improve the treatment of heterogenous disorders such as depression.“You are all aware of the revolution in data science and artificial intelligence that has been changing the way we think about science and society in general,” Gordon said. “We want to take that revolution and harness it for psychiatry.”Gordon described a technology known as computational phenotyping, which aims to break down depressive symptoms into discrete units and then mathematically define those units. Rather than asking where in the brain happiness is controlled, for example, computational phenotyping asks where in the brain are the different behavioral components that together make up happiness.He highlighted one study that used brain imaging data of people playing a game of chance on their phones to calculate reward prediction error. Basically, when people are about to decide something involving reward/loss, they have some expectations of how they will react to winning or losing, which guides their decision. Normally the outcomes and expectations match, but in many people with depression, reward prediction is off (rewards are not as pleasurable as thought, which lowers a desire to seek future rewards, for example). This study found that reward prediction in the participants could be localized to two discrete brain regions: the ventral striatum and medial prefrontal cortex.Other brain imaging studies have found these same two regions show reduced activity in many depressed patients. Gordon noted that linking specific brain regions with specific traits might help with precision medicine efforts. Based on a patient’s symptom profile, physicians might be able to determine which brain regions are affected and then identify the optimal treatment.That treatment might involve a strategy guided by neural circuit discoveries, which highlights how these two long-term NIMH goals might one day converge. ■ ISSUES NewArchived

Investigation of Photonic Integrated Circuits with Low-Loss Bragg Gratings

AbstractThe impact of physical parameters of uniform fiber Bragg grating (U-FBG) like grating period, length of grating, and width of grating on the performance of U-FBG fiber by using finite differences time domain (FDTD) based on surface plasmon polaritons (SPP) is evaluated. An FBG is similar to a distributed Bragg reflector created in a small segment of optical fiber that reflects some particular wavelengths of light and transmits the other wavelengths. It is observed that the maximum received optical power at the reflected port achieved is −1.67×10-6 w/m2 with silver (Ag) profile material of U-FBG at 0.1 w/m2 input transmission power and wavelength of 1.55 μm with 0.9 μm grating length and 0.2 μm grating width. The result shows that the received optical power is changing by optimizing the physical parameters of U-FBG.

Sensitivity Improvement of a Surface Plasmon Resonance Sensor Based on Two-Dimensional Materials Hybrid Structure in Visible Region: A Theoretical Study.

In this paper, we propose a surface plasmon resonance (SPR) sensor based on two-dimensional (2D) materials (graphene, MoS2, WS2 and WSe2) hybrid structure, and theoretically investigate its sensitivity improvement in the visible region. The thickness of metal (Au, Ag or Cu) and the layer number of each 2D material are optimized using genetic algorithms to obtain the highest sensitivity for a specific wavelength of incident light. Then, the sensitivities of proposed SPR sensors with different metal films at various wavelengths are compared. An Ag-based SPR sensor exhibits a higher sensitivity than an Au- or Cu-based one at most wavelengths in the visible region. In addition, the sensitivity of the proposed SPR sensor varies obviously with the wavelength of incident light, and shows a maximum value of 159, 194 or 155°/RIU for Au, Ag or Cu, respectively. It is demonstrated that the sensitivity of the SPR sensor based on 2D materials’ hybrid structure can be further improved by optimizing the wavelength of incident light.

Possible Enhancement of Photodynamic Therapy (PDT) Colorectal Cancer Treatment when Combined with Cannabidiol.

Colorectal Cancer (CRC) has a high mortality rate and is one of the most difficult diseases to manage due to tumour resistance and metastasis. The treatment of choice for CRC is reliant on the phase and time of diagnosis. Despite several conventional treatments available to treat CRC (surgical excision, chemo-, radiationand immune-therapy), resistance is a major challenge, especially if it has metastasized. Additionally, these treatments often cause unwanted adverse side effects and so it remains imperative to investigate alternative combination therapies. Photodynamic Therapy (PDT) is a promising treatment modality for the primary treatment of CRC, since it is non-invasive, has few side effects and selectively damages only cancerous tissues, leaving adjacent healthy structures intact. PDT involves three fundamentals: a Photosensitizer (PS) drug localized in tumour tissues, oxygen, and light. Upon PS excitation using a specific wavelength of light, an energy transfer cascade occurs, that ultimately yields cytotoxic species, which in turn induces cell death. Cannabidiol (CBD) is a cannabinoid compound derived from the Cannabis sativa plant, which has shown to exert anticancer effects on CRC through different pathways, inducing apoptosis and so inhibiting tumour metastasis and secondary spread. This review paper highlights current conventional treatment modalities for CRC and their limitations, as well as discusses the necessitation for further investigation into unconventional active nanoparticle targeting PDT treatments for enhanced primary CRC treatment. This can be administered in combination with CBD, to prevent CRC secondary spread and enhance the synergistic efficacy of CRC treatment outcomes, with less side effects.

Structural design of soft robotics using a joint structure of photoresponsive polymers

Photoresponsive polymers (PRPs) have a non-contact bending behavior based on their position when they are irradiated by a specific wavelength of light. In this paper, the behavior of self-deforming PRPs is discussed through multiscale simulations and structural designs. In repeated bending, it is difficult to return to the initial state through different paths because the PRP moves periodically in the same path. We designed an anti-obstructing motion of a PRP operator based on a nonlinear co-rotational finite element model, which could not be designed for the existing bending behavior. The PRP operator can move independently in specified directions by attaching an opaque part to the PRP operator as a joint structure. The device can be divided into two separate regions. One region can be bent to move the desired object, and then the PRP operator can move away, avoiding the object by bending in the other region. The PRP operators can take actions whether to move an object or to avoid an obstacle and adjust the friction force of robot feet based on bio-inspiration. In our experiments, the production process of PRPs is presented, and operations implemented in soft robot applications of gear rotation and walking.

Non‐invasive Neuromodulation Using Ultrasound

The discovery of light sensitive proteins led to the development of optogenetics and allowed the precise manipulation of neuronal and non‐neuronal cells. This technique uses particular wavelengths of light to manipulate both neuronal and non‐neuronal cells [2, 5]. It has enabled the study of information processing in the brain and recent studies are looking into clinical translational applications of the technique [1]. Despite the advantages offered by optegenetics, it has the drawback of being invasive as light does not penetrate skin past a few millimeters. It is not possible to target deep tissue within the body using this technique and this limits the application in the context of diseases such as Parkinson’s [3] or heart malfunction [4].We are developing devices that can non‐invasively manipulate cells using a technique termed “sonogenetics”. This technique uses a combination of engineering cells to be more sensitive to mechanical stimuli as well as developing ultrasound transducers capable of stimulating cells in freely moving, awake mice. We demonstrate the development of miniature transducers made from non‐hysteretic single crystal lithium niobate to be used for the development of sonogenetics. In addition, we o er mathematical insights to the mechanism of action of ultrasound on neurons. Our analysis of membrane deflection enables us to predict cellular activity based on the applied ultrasound stimulus. By extension, we use this analytical framework to inform the development of transducers and stimulation parameters for achieving non‐invasive stimulation of cells.Support or Funding InformationWM Keck FoundationNational Institute of HealthMembrane Deflection and Capacitance Change due to Ultrasounda–d) Membrane deflection due to an ultrasound stimulus, with parameters 7 MHz and 1 MPa pressure. The stimulus is provided for 10 ms, the resulting area change(e) and the capacitance (f) are then calculated from the input parameters. The value of capacitance generated in this model is then used in a Hodgkin‐Huxley neuron model to determine action potential generation.Figure 1a) LN transducer housed in a MMCX coaxial connector designed for long term behavioral studies in awake, freely‐moving mice. b) Device mounted on a mouse skull to be used for characterization using an automated hydrophone setup (c). d)Pressure profile over the transducer face with a 450 mV input results in up to 2 MPa pressures. e) Transducer attached to mouse skull for long term behavioral studies.Figure 2

Histopathological determinants of autofluorescence patterns in oral carcinoma.

Biological tissues (including oral mucosa) can absorb and re-emit specific light wavelengths, detectable through spectrophotometric devices. Such a phenomenon is known as "autofluorescence" (AF). Several devices evaluating tissue AF have been developed and commercialized in the last two decades. Among these, the VELscope® system has been proposed as a visual diagnostic aid for potentially malignant disorders and malignant lesions of the oral mucosa. In the present pilot study, we investigated which are the main histopathological features possibly related to variations in AF patterns in a set of 20 oral squamous cell verrucous carcinoma. Among all the histological features investigated, only the mean width of keratin was significantly different between hypofluorescent and hyperfluorescent carcinomas. The results of the present study demonstrate that AF features of oral malignant lesions are significantly associated with the width of their keratin layer.

Mutual impact of clinically translatable near-infrared dyes on photoacoustic image contrast and in vitro photodynamic therapy efficacy.

.Photodynamic therapy (PDT), a spatially localized phototoxic therapy that involves irradiation of a photosensitizer (PS) with specific wavelengths of light, has shown exceptional promise in impacting cancer treatment outcomes, particularly oral cancer. To reduce PDT outcome variability, attempts toward image-guided personalized PDT are being pursued by monitoring PS uptake either via fluorescence or photoacoustic imaging (PAI), a nonionizing modality dependent on optical absorption properties of the tissue. PAI-guided PDT requires a near-infrared contrast agent for deep tissue imaging with minimal photobleaching effect. We evaluate the impact of PDT agent, benzoporphyrin derivative (BPD), on PAI agent indocyanine green (ICG) and vice versa, given that they have different optical absorption properties and singlet oxygen quantum yields for PDT. Specifically, we demonstrate in two oral squamous cell carcinoma lines (FaDu and SCC4) that ICG has minimal effect on BPD PDT efficacy when irradiated with either a continuous or pulsed laser. Furthermore, the impact of BPD on ICG photodegradation was monitored with PAI in tissue-mimicking phantoms. These studies inform us that the combination of BPD and ICG can be utilized for PAI-guided PDT. However, researchers need to consider the photodegradation effects of ICG in the presence of BPD when designing their drug delivery strategies for PAI-guided PDT.

Deconvoluting Wavelengths Leading to Fluorescent Light Induced Inflammation and Cellular Stress in Zebrafish (Danio rerio)

Fluorescent light (FL) has been shown to induce a cellular immune and inflammatory response that is conserved over 450 MY of evolutionary divergence and among vertebrates having drastically different lifestyles such as Mus musculus, Danio rerio, Oryzias latipes and Xiphophorus maculatus. This surprising finding of an inflammation and immune response to FL not only holds for direct light receiving organs (skin) but is also observed within internal organs (brain and liver). Light responsive genetic circuitry initiated by the IL1B regulator induces a highly conserved acute phase response in each organ assessed for all of biological models surveyed to date; however, the specific light wavelengths triggering this response have yet to be determined so investigation of mechanisms and/or light specific molecule(s) leading to this response are difficult to assess. To understand how specific light wavelengths are received in both external and internal organs, zebrafish were exposed to specific 50 nm light wavebands spanning the visible spectrum from 300–600 nm and the genetic responses to each waveband exposure were assessed. Surprisingly, the induced cellular stress response previously observed following FL exposure is not triggered by the lower “damaging” wavelengths of light (UVB and UVA from 300–400 nm) but instead is maximally induced by higher wavelengths ranging from 450–500 nm in skin to 500–600 nm in both brain and liver).

Photomodulation of Inhibitory Neurotransmission. Insights from Molecular Modeling

Photoswitches are molecules that change their conformation with light of specific wavelength. These light-regulated molecules can be designed to target ion channels, thus providing a unique tool for precise spatial and temporal control of ion channel functioning. Recently, we have applied a multidisciplinary approach to design, synthesize and functionally characterize two of such photoswitches, azo-NZ1 [Maleeva et al. Br. J. Pharmacol. 2019] and Glyght [Gomila-Juaneda et al. BioRxiv 2019], targeting GABA and glycine receptors, respectively. Using homology modeling and molecular docking, we have provided a molecular explanation of the light-dependent effect of these two photoswitchable ligands, as observed in in vitro electrophysiology experiments and in vivo tadpole behavioral assays. Azo-NZ1 is composed of a nitrazepam moiety merged to an azobenzene photoisomerizable group, yet it has an inhibitory effect on GABAA receptors under visible light and also inhibits benzodiazepine-insensitive GABAC (rho2) receptors. Molecular modeling, combined with electrophysiology and mutagenesis experiments, shows that addition of the sulfonyl azobenzene unexpectedly converts the ligand into a pore blocker. Glyght is also an azobenzene-containing benzodiazepine, yet it acts selectively on glycine receptors as a negative modulator and its inhibitory action increases under UV light. Molecular modeling suggests that Glyght binds to a novel allosteric site located at the interface between the extracellular and transmembrane domains. The two aforementioned photoswitches pave the way towards photomanipulation of inhibitory (gabaergic and glycinergic) neurotransmission, with potential applications in understanding inhibitory circuits in intact animals and in development of drug-based phototherapies.

Experimental and theoretical exploration of photophysics and trans-cis photoisomerization of styrylbenzene conjugated terpyridine complexes of Ru(II): Strong effect of deprotonation from second coordination sphere

We report herein synthesis, characterization, photophysics, and photo-isomerization behaviors of a new class of heteroleptic Ru(II) complexes incorporating styrylbenzene conjugated terpyridine and 2,6–bis(benzimidazole–2–yl)pyridine ligands. All the complexes display moderately strong luminescence at room temperature with appreciably long lifetime varying in the range between 7.2 and 62.2 ns, depending upon the electronic nature of substituent as well as the solvent. The styrylbenzene moiety induces trans to cis isomerization resulting in remarkable changes in absorption and both steady state and time-resolved luminescence spectral characteristics upon irradiating with UV light. Reversal of cis to trans isomerization were also achieved on interacting with visible light as well as UV light of specific wavelength. Removal of two benzimidazole NH protons from the secondary coordination sphere of the complexes were made possible upon treatment with strong base accompanying with substantial modulation of their absorption and emission spectral properties. Interestingly, rate constant as well as quantum yield of photoisomerization dramatically increases upon deprotonation of the imidazole NH protons. Computational studies employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) were also executed for understanding the electronic charge distribution within the complex backbone and appropriate assignment of the observed spectral bands. In addition, observed spectral trend upon NH deprotonation as well as deprotonation-induced photoisomerization processes were also compared with the calculated results.

Development of a Theoretical Model That Predicts Optothermal Energy Conversion of Gold Metallic Nanoparticles

Gold nanoparticles (AuNPs) can be found in different shapes and sizes, which determine their chemical and physical characteristics. Physical and chemical properties of metallic NPs can be tuned by changing their shape, size, and surface chemistry; therefore, this has led to their use in a wide variety of applications in many industrial and academic sectors. One of the features of metallic NPs is their ability to act as optothermal energy converters, where they absorb light at a specific wavelength and heat up their local nanosurfaces. This feature has been used in many applications where metallic NPs get coupled with thermally responsive systems to trigger an optical response. In this study, we synthesized AuNPs that are spherical in shape with an average diameter of 20.07 nm. This work assessed simultaneously theoretical and experimental techniques to evaluate the different factors that affect heat generation at the surface of AuNPs when exposed to a specific light wavelength. The results indicated that laser power, concentration of AuNPs, time × laser power interaction, and time illumination, were the most important factors that contributed to the temperature change exhibited in the AuNPs solution. We report a regression model that allows predicting heat generation and temperature changes with residual standard errors of less than 4%. These results are highly relevant in the future design and development of applications where metallic NPs are incorporated into systems to induce a temperature change triggered by light exposure.