Loss Of Transparency Research Articles

Radiation Damage in Polyethylene Naphthalate Thin-Film Scintillators.

This paper describes the scintillation features and the radiation damage in polyethylene naphthalate 100 µm-thick scintillators irradiated with an 11 MeV proton beam and with a 1 MeV electron beam at doses up to 15 and 85 Mrad, respectively. The scintillator emission spectrum, optical transmission, light yield loss, and scintillation pulse decay times were investigated before and after the irradiation. A deep blue emission spectrum peaked at 422 nm, and fast and slow scintillation decay time constants of the order of 1–2 ns and 25–30 nm, respectively, were measured. After irradiation, transmittance showed a loss of transparency for wavelengths between 380 and 420 nm, and a light yield reduction of ~40% was measured at the maximum dose of 85 Mrad.

Time-dependent in situ structural and cellular aberrations in rabbit cornea in vivo after mustard gas exposure

An array of corneal pathologies collectively called mustard gas keratopathy (MGK) resulting from ocular exposure to sulfur mustard (SM) gas are the most prevalent chemical warfare injury. MGK involves chronic ocular discomfort that results in vision impairment. The etiology of MGK remains unclear and poorly understood primarily due to a lack of scientific data regarding structural and cellular changes in different layers of the cornea altered by mustard vapor exposure in vivo. The goals of this study were to (a) characterize time-dependent changes in different layers of corneal epithelium, stroma, and endothelium in live animals in situ by employing state-of-the-art multimodal clinical ophthalmic imaging techniques and (b) determine if SM-induced acute changes in corneal cells could be rescued by a topical eye drop (TED) treatment using in an established rabbit in vivo model. Forty-five New Zealand White Rabbit eyes were divided into four groups (Naïve, TED, SM, and SM + TED). Only one eye was exposed to SM (200 mg-min/m3 for 8 min), and each group had three time points with six eyes each (Table-1). TED was topically applied twice a day for seven days. Clinical eye examinations and imaging were performed in live rabbits with stereo, Slit-lamp, HRT-RCM3, and Spectralis microscopy system. Fantes grading, fluorescein staining, Schirmer's tests, and applanation tonometry were conducted to measure corneal haze, ocular surface aberrations, tears, and intraocular pressure respectively. H&E and PSR staining were used for histopathological cellular changes in the cornea. In vivo confocal and OCT imaging revealed significant changes in structural and morphological appearance of corneal epithelium, stroma, and endothelium in vivo in SM-exposed rabbit corneas in a time-dependent manner compared to naïve cornea. Also, SM-exposed eyes showed loss of corneal transparency characterized by increased stromal thickness and light-scattering myofibroblasts or activated keratocytes, representing haze formation in the cornea. Neither naive nor TED-alone treated eyes showed any structural, cellular, and functional abnormalities. Topical TED treatment significantly reduced SM-induced abnormalities in primary corneal layers. We conclude that structural and cellular changes in primary corneal layers are early pathological events contributing to MGK in vivo, and efficient targeting of them with suitable agents has the potential to mitigate SM ocular injury.

Efficient visible light-harvesting film with multi-channel sterilization behavior for ultra-persistent freshness of perishable products

In light of the microbial spoilage of perishable products such as fruits and vegetables, this work pioneered a visible light-harvesting film with multi-channel sterilization mode by the demand-oriented construction of functional fillers, aiming to efficiently utilize abundant sunlight to achieve long-term preservation of fruits and vegetables. In detail, cubic TiO2-anchored porous nitrogen-rich nanocarbons (TPNC) with excellent photothermal and photocatalytic activities was first prepared by two-step annealing of NH2-MIL-125(Ti) precursor in different atmospheres, which was incorporated as filler into chitosan (CS) matrix to obtain a series of TPNC-CS nanocomposite films. Benefiting from the synergy between the integrated photothermal and photocatalytic sterilization of TPNC and the inherent antibacterial properties of CS, the TPNC0.30-CS film exhibited outstanding antibacterial capacity with short processing times (10 min) and high antibacterial rates (≥99.4 %). The significantly prolonged shelf life of kumquats treated with TPNC0.30-CS film confirmed its satisfactory preservation ability. Although at the cost of a slight loss of transparency, upgraded performances in mechanical strength, barrier capability, and proven biosafety served as cornerstones for the practical application of TPNC-CS films. These desirable properties declared TPNC-CS films as a promising microbial control barrier for efficient preservation of fruits and vegetables.

Wavelength-Dependent Nonlinear Absorption in Platinum Nanoparticles at Off-Resonant Wavelength

In order to obtain optical nonlinear materials with high transparency and low propagation loss in the visible and infrared range, noble metal materials in the off-resonant band have become a hot spot in the optical field in recent years. Therefore, the nonlinear absorption characteristics of platinum nanoparticles (PtNPs) with the surface plasmon resonance (SPR) in the ultraviolet band were investigated with multi-wavelength (500–700 nm) nanosecond Z-scan technology. The measurement results showed that the SPR wavelength of PtNPs was far away from the excitation wavelength, but there were still the saturated absorption (SA) and the reverse saturated absorption (RSA) phenomena, and the size of nonlinear absorption was related to the excitation wavelength and the excitation energy. When the excitation wavelength was constant, with the increase in excitation energy, PtNPs converted from SA to RSA. When the excitation energy was constant, with the excitation wavelength approaching SPR, PtNPs also converted from SA to RSA. The SA and RSA phenomena in the off-resonant region were complementary to the systematic study of the nonlinearity of PtNPs.

Increasing the Colloidal Stability of Non-alcoholic Beer Using "BREWERS CLAREX" Enzyme Preparation

Introduction. The colloidal stability of beer is one of the important characteristics that ensure the high competitiveness of the drink and the interest of consumers in it. However, the finished beer is a complex system, the equilibrium of which can be disturbed under the influence of non-optimal conditions of transportation and storage, which leads to the loss of the original transparency. This makes it necessary to use in the production process such modes and technological methods that provide high colloidal stability of the finished beer, including non-alcoholic beer. One of these methods is the use of enzyme preparations of the proteolytic type of action, which reduce the concentration of protein compounds that can participate in the formation of colloidal opacities during the production of beer. Purpose. The purpose of our study was to determine the results of the application of the enzyme preparation "BREWERS CLAREX" added to the wort before the start of the main fermentation. Materials and Methods. The results of the application of the enzyme preparation "BREWERS CLAREX" added to the wort before the start of the main fermentation were evaluated by the content of "sensitive" proteins in the finished non-alcoholic beer, its precipitation limit with ammonium sulfate and turbidity. Results. A rational dosage of the enzyme preparation was established, equal to 2 cm3/Gl of wort. It was found that the use of this enzyme preparation can significantly reduce the content of protein substances that can initiate the formation of turbidity, and also increases the precipitation limit of finished non-alcoholic beer with ammonium sulfate. However, a direct correlation between the use of the enzyme preparation and the turbidity of the finished non-alcoholic beer obtained from different batches of malt, was not determined. Conclusions. It was found that the use of the “BREWERS CLAREX” enzyme preparation in a rational dosage ensured a shelf life of the finished non-alcoholic beer of at least 180 days

P‐55: Development of Photosensitive Material for Mini/MicroLED Displays

We developed photosensitive material for Mini/Micro LED display. The material is negative tone type and alkaline developable. Minimum resolution of the material is 10 μm with 10 μm thickness, and taper angle is approximately 80°. The material has high transparency and good heat resistance. Transparency of 10 μm thickness cured film is more than 90% at 400 nm, Tg of cured film is over 250°C. And the material has durability against blue light (405 nm). After radiation of blue light at 50°C for 400 hrs, the material has no transparency loss and no film thickness loss.

Notch1 signaling in keratocytes maintains corneal transparency by suppressing VEGF expression.

SummaryThe cornea fends off chemicals, dirt, and infectious particles and provides most of the eye’s focusing power. Corneal transparency is of paramount importance to normal vision, yet how it is established and maintained remains unclear. Here, we ablated Notch1 in keratocytes using Twist2-Cre mice and found that Twist2-Cre; Notch1f/f mice developed stroma expansion and neovascularization, followed by hyperproliferation and metaplasia of corneal epithelial progenitor cells and plaque formation at central cornea, leading to loss of transparency. Development of these phenotypes does not involve bacteria-caused inflammation; instead, Notch1 deletion upregulates Vegfa and Vegfc via Hif1α in keratocytes. Vascular endothelial growth factor (VEGF) receptor inhibitor axitinib prevented development of these anomalies in Twist2-Cre; Notch1f/f mice, suggesting that VEGFs secreted by keratocytes promote not only neovascularization but also proliferation and metaplasia of epithelial progenitor cells at central cornea. This study uncovers a Notch1-Hif1α-VEGF pathway in keratocytes that maintains corneal transparency and represents a potential target for treatment of related corneal disorders.

A mathematical model for the corneal transparency problem

AbstractUnderstanding the physical basis of corneal transparency has been a subject of interest amongst physicists, basic scientists and ophthalmologists. Impairment of corneal clarity is a significant cause of visual morbidity worldwide. Thus, it is essential to understand the mechanisms behind corneal transparency and how the alterations due to corneal pathologies affect vision. We use Maxwell’s equations to model light propagation in ocular tissues and a nodal discontinuous Galerkin method combined with an explicit Runge-Kutta method to simulate light propagation in normal and pathological corneas. Our simulation results illustrate that an increase in the diameter of some fibres causes an increase in backscattering. Thus, these may represent some of the physical changes in the cornea that might result in loss of transparency and visual morbidity.

Acrylamide-modified polyvinyl alcohol and combined with graphene oxide for low dielectric constant composite films

High transparency, low dielectric, and robustness in polymeric materials have been targeted performance in high-frequency communication applications for the field of smart wearable electric devices. In terms of transparency property, polyvinyl alcohol (PVA) possesses great potential as optical electric material, due to its excellent optical transmission, low cost, and chemical resistance. However, the dielectric property of PVA is confined by abundant polar groups such as hydroxyl groups in the structure. Improving the PVA dielectric performances from the structure is still a great challenge. Herein, we propose a novel structure optimization approach by designing a Michael addition reaction between PVA and acrylamide (AM) to decrease its polar segments and to develop high transparency and low dielectric loss graphene oxide (GO)/PVA-AM composite film. a small content of AM has little effect on the regularity of PVA chains, which increases the chain entanglement between PVA-AM and eventually improves the strength. Meanwhile, the low dipoles (i.e., introducing C-C and C-H groups) can distinctly reduce its dielectric constant. Besides, the addition of a certain amount of GO further enhances the strength of the film. Tensile strength of 142.47 MPa, dielectric constant as low as 3.49, and dielectric loss of only 0.055 were achieved, which is superior to those of pure PVA and PVA/GO composite films reported by previous literature. It has great potential in the field of dielectric materials for high-frequency communication.

Investigating Scarless Tissue Regeneration in Embryonic Wounded Chick Corneas.

Chick embryonic corneal wounds display a remarkable capacity to fully and rapidly regenerate, whereas adult wounded corneas experience a loss of transparency due to fibrotic scarring. The tissue integrity of injured embryonic corneas is intrinsically restored with no detectable scar formation. Given its accessibility and ease of manipulation, the chick embryo is an ideal model for studying scarless corneal wound repair. This protocol demonstrates the different steps involved in wounding the cornea of an embryonic chick in ovo. First, eggs are windowed at early embryonic ages to access the eye. Second, a series of in ovo physical manipulations to the extraembryonic membranes are conducted to ensure access to the eye is maintained through later stages of development, corresponding to when the three cellular layers of the cornea are formed. Third, linear cornea wounds that penetrate the outer epithelial layer and the anterior stroma are made using a microsurgical knife. The regeneration process or fully restored corneas can be analyzed for regenerative potential using various cellular and molecular techniques following the wounding procedure. Studies to date using this model have revealed that wounded embryonic corneas display activation of keratocyte differentiation, undergo coordinated remodeling of ECM proteins to their native three-dimensional macrostructure, and become adequately re-innervated by corneal sensory nerves. In the future, the potential impact of endogenous or exogenous factors on the regenerative process could be analyzed in healing corneas by using developmental biology techniques, such as tissue grafting, electroporation, retroviral infection, or bead implantation. The current strategy identifies the embryonic chick as a crucial experimental paradigm for elucidating the molecular and cellular factors coordinating scarless corneal wound healing.

Fine-needle diathermy for corneal vascularisation.

Background:Corneal angiogenesis occurs as a sequel to an insult and it brings with it cells that mediate immunity as well as repair and aids in flushing toxins out. These vessels are formed in haste and leak lipid and cells, ultimately resulting in loss of transparency, lipid keratopathy and immunogenicity. So, they may need treatment prior to an optical keratoplasty.Purpose:To demonstrate the procedure of Fine Needle Diathermy (FND) to treat corneal neovascularization, its indications and contraindications.Synopsis:FND uses coagulating current from a monopolar cautery unit to occlude the afferent and efferent blood vessels. FND works best at the stage of mature vessel formation. The needle is placed across a tuft of vessels or parallel to a single large vessel, being mindful of the depth and direction. FND is avoided in necrotic tissue where the blood vessel is needed for healing process. Occlusion of the vessel in these situations may result in tissue melt.Highlights:Corneal neovascularization follows the stages of latent phase, active neovascularization, mature vessel formation and then regression. The treatment modality depends on the stage of angiogenesis. FND works best for neovascularization due to infectious keratitis. Keratoplasty is best performed 3 to 4 months later when regression of corneal vascularization occurs.Video Link: https://youtu.be/2RK6d_a2Gdc

I overthink—Therefore I am not: An active inference account of altered sense of self and agency in depersonalisation disorder

This paper considers the phenomenology of depersonalisation disorder, in relation to predictive processing and its associated pathophysiology. To do this, we first establish a few mechanistic tenets of predictive processing that are necessary to talk about phenomenal transparency, mental action, and self as subject. We briefly review the important role of ‘predicting precision’ and how this affords mental action and the loss of phenomenal transparency. We then turn to sensory attenuation and the phenomenal consequences of (pathophysiological) failures to attenuate or modulate sensory precision. We then consider this failure in the context of depersonalisation disorder. The key idea here is that depersonalisation disorder reflects the remarkable capacity to explain perceptual engagement with the world via the hypothesis that “I am an embodied perceiver, but I am not in control of my perception”. We suggest that individuals with depersonalisation may believe that ‘another agent’ is controlling their thoughts, perceptions or actions, while maintaining full insight that the ‘other agent’ is ‘me’ (the self). Finally, we rehearse the predictions of this formal analysis, with a special focus on the psychophysical and physiological abnormalities that may underwrite the phenomenology of depersonalisation.

Overcoming Shockley-Queisser limit using halide perovskite platform?

<h2>Summary</h2> Single-junction photovoltaics have a theoretical efficiency limit of 33.7%, with over 50% energy losses in thermalization and in-band transparency. Prior engineering at system levels has been developed to reduce these losses and break the Shockley-Queisser (SQ) limit; many require high-standard manufacturing but deliver mild efficiency enhancement. A breakthrough can be found from the materials perspective. Halide perovskites with various physical merits may provide the platform to overcome both thermalization and in-band transparency losses and thus elevate efficiency by two factors. For example, long-lived hot carriers in perovskite could boost the photovoltage to exceed its band gap or to execute a multi-exciton generation process to double the photocurrent. A delicately designed quantum structure could overcome the in-band losses by mechanisms such as intermediate band, multiple quantum well cascade, and photoferroic effect. Here, we discuss the opportunity, feasibility, and challenges of overcoming the SQ limit by designing upon a perovskite platform.

Comparative analysis by UV-vis and FT-IR spectroscopy of the chemical degradation of polyethylene used as greenhouse cover film

Greenhouse culture usually requires a controlled environment for optimum plant growth and production. However, regular plastic films used for their coverage create an uncontrolled microclimate, especially in areas with harsh climatic conditions. Three low-density polyethylene (LDPE) films, a commercial ordinary film, a three-layer film, and a monolayer film were used as a greenhouse covering materials to study its behavior in presence of a cultivar and harsh climatic conditions. They were exposed to natural weathering and UV radiations in the semi-arid environment of a city located in northern Algeria. This study aims to investigate and compare the lifespan and deterioration of the materials used for a 5-month period to improve future greenhouse cultivation. Fourier-transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectrophotometry (UV-vis) were used to study the aging and degradation of these films. FTIR 1030/2848 bands ratio was used to determine the chemical oxidation rate of each film. Visible changes in the material structure were also recorded during the aging process. Materials underwent photo and thermo degradation, leading to chemical and mechanical changes. The monolayer film has suffered more mechanical degradation than the multilayer films, leading to its total crumbling in a short lifetime. The three-layer and ordinary films were more resistant and showed approximately the same behavior towards the rough climatic conditions. Furthermore, the UV-visible spectrum indicated a high loss of transparency of the polyethylene films during their use. The two studied multilayer films seem more adequate for greenhouse culture under the semi-arid regions.

A quality framework for statistical algorithms

As national statistical offices (NSOs) modernize, interest in integrating machine learning (ML) into official statisticians’ toolbox is growing. Two challenges to such an integration are the potential loss of transparency from using “black-boxes” and the need to develop a quality framework. In 2019, the High-Level Group for the Modernisation of Official Statistics (HLG-MOS) launched a project on machine learning with one of the objectives being to address these two challenges. One of the outputs of the HLG-MOS project is a Quality Framework for Statistical Algorithms (QF4SA). While many quality frameworks exist, they have been conceived with traditional methods in mind, and they tend to target statistical outputs. Currently, machine learning methods are being looked at for use in processes producing intermediate outputs, which lead to a final statistical output. Therefore, the QF4SA does not replace existing quality frameworks; it complements them. As the QF4SA targets intermediate outputs and not necessarily the final statistical output, it should be used in conjunction with existing quality frameworks to ensure that high-quality outputs are produced. This paper presents the QF4SA, as well as some recommendations for NSOs considering the use of machine learning in the production of official statistics.

On multi-human multi-robot remote interaction: a study of transparency, inter-human communication, and information loss in remote interaction

In this paper, we investigate how to design an effective interface for remote multi-human–multi-robot interaction. While significant research exists on interfaces for individual human operators, little research exists for the multi-human case. Yet, this is a critical problem to solve to make complex, large-scale missions achievable in which direct operator involvement is impossible or undesirable, and robot swarms act as a semi-autonomous agents. This paper’s contribution is twofold. The first contribution is an exploration of the design space of computer-based interfaces for multi-human multi-robot operations. In particular, we focus on agent transparency and on the factors that affect inter-human communication in ideal conditions, i.e., without communication issues. Our second contribution concerns the same problem, but considering increasing degrees of information loss, defined as intermittent reception of data with noticeable gaps between individual receipts. We derived a set of design recommendations based on two user studies involving 48 participants.

Effect of Sorbitol on Alpha-Crystallin Structure and Function.

Loss of eye lens transparency due to cataract is the leading cause of blindness all over the world. While aggregation of lens crystallins is the most common endpoint in various types of cataracts, chaperone-like activity (CLA) of α-crystallin preventing protein aggregation is considered to be important for maintaining the eye lens transparency. Osmotic stress due to increased accumulation of sorbitol under hyperglycemic conditions is believed to be one of the mechanisms for diabetic cataract. In addition, compromised CLA of α-crystallin in diabetic cataract has been reported. However, the effect of sorbitol on the structure and function of α-crystallin has not been elucidated yet. Hence, in the present exploratory study, we described the effect of varying concentrations of sorbitol on the structure and function of α-crystallin. Alpha-crystallin purified from the rat lens was incubated with varying concentrations of sorbitol in the dark under sterile conditions for up to 5 days. At the end of incubation, structural properties and CLA were evaluated by spectroscopic methods. Interestingly, different concentrations of sorbitol showed contrasting results: at lower concentrations (5 and 50 mM) there was a decrease in CLA and subtle alterations in secondary and tertiary structure but not at higher concentrations (500 mM). Though, these results shed a light on the effect of sorbitol on α-crystallin structure-function, further studies are required to understand the mechanism of the observed effects and their implication to cataractogenesis.

Engineered Raman Lasing in Photonic Integrated Chalcogenide Microresonators

AbstractPhotonic integrated Raman lasers have extended the wavelength range of chip‐scale laser sources and have enabled applications including molecular spectroscopy, environmental analysis, and biological detection. Yet, the performance is strongly determined by the pumping condition and Raman shift value of nonlinear medias, leaving challenges to have a widely and continuously tunable Raman laser (e.g., over 100 nm). Here, photonic engineered Raman lasers based on chip‐integrated chalcogenide microresonators are demonstrated. The home‐developed chalcogenide photonic platform is of high nonlinearity, wide transparency, and low loss. The strong and broadband material Raman response has promised rich dynamics of Raman lasing. Indeed, both single‐mode Raman lasing and a broadband Raman‐Kerr comb, which are found engineered by tuning the dispersion of the chalcogenide microresonator, are demonstrated. The single‐mode Raman laser, together with its cascaded modes, supports a gap‐free tuning range over 140 nm, while the threshold power is as low as 3.25 mW. The results may contribute to the understanding of Raman and Kerr nonlinear interactions in dissipative and nonlinear microresonators, and on application aspect, may pave a way to integrated and efficient laser sources that is desired in spectroscopic applications in the infrared.

Optical, mechanical, and antimicrobial properties of bio‐based composites of poly(L‐lactic acid) and D‐limonene/β‐cyclodextrin inclusion complex

AbstractComposites made of poly(l‐lactic acid) (PLLA) and β‐cyclodextrin/D‐limonene inclusion complex (CD‐Lim) are prepared to develop novel food packaging material with antibacterial properties. The composites are formulated with bio‐based materials that are also biodegradable. The addition of CD‐Lim to PLLA results in enhanced permeability and water uptake. Optical properties of PLLA/CD‐Lim composites also significantly vary compared to plain PLLA, with partial loss of transparency and gloss, but sizably increased barrier to UV light, which imparts protection from oxidation to lipid‐containing food. The mechanical properties of the composite films are also affected by composition. Most notably, PLLA films containing CD‐Lim display significant antibacterial and antifungal properties, proving their potential as active food packaging films.

Roles of Epithelial and Mesenchymal TRP Channels in Mediating Inflammatory Fibrosis.

The maintenance of normal vision is dependent on preserving corneal transparency. For this to occur, this tissue must remain avascular and its stromal architecture needs to be retained. Epithelial transparency is maintained provided the uppermost stratified layers of this tissue are composed of terminally differentiated non-keratinizing cells. In addition, it is essential that the underlying stromal connective tissue remains avascular and scar-free. Keratocytes are the source of fibroblasts that are interspersed within the collagenous framework and the extracellular matrix. In addition, there are sensory nerve fibers whose lineage is possibly either neural crest or mesenchymal. Corneal wound healing studies have been undertaken to delineate the underlying pathogenic responses that result in the development of opacification following chemical injury. An alkali burn is one type of injury that can result in severe and long- lasting losses in ocular transparency. During the subsequent wound healing process, numerous different proinflammatory cytokines and proteolytic enzymes undergo upregulation. Such increases in their expression levels induce maladaptive expression of sustained stromal inflammatory fibrosis, neovascularization, and losses in the smooth optical properties of the corneal outer surface. It is becoming apparent that different transient receptor potential channel (TRP) isoforms are important players in mediating these different events underlying the wound healing process since injury upregulates both their expression levels and functional involvement. In this review, we focus on the involvement of TRPV1, TRPA1 and TRPV4 in mediating some of the responses that underlie the control of anterior ocular tissue homeostasis under normal and pathological conditions. They are expressed on both different cell types throughout this tissue and also on corneal sensory nerve endings. Their roles have been extensively studied as sensors and transducers of environmental stimuli resulting from exposure to intrinsic modulators and extrinsic ligands. These triggers include alteration of the ambient temperature and mechanical stress, etc., that can induce pathophysiological responses underlying losses in tissue transparency activated by wound healing in mice losses in tissue transparency. In this article, experimental findings are reviewed about the role of injury-induced TRP channel activation in mediating inflammatory fibrotic responses during wound healing in mice.