Luminance Distribution Research Articles

A Study on Pendant and Blackboard Asymmetric Lens LED Luminaires for Optimal Illumination in Classrooms

This study examines the transformative impact of integrating pendant asymmetric lens (PAL) and blackboard asymmetric lens (BAL) LED luminaires to enhance classroom lighting, with the goals of replicating the ambient effects of natural daylight and promoting energy efficiency. This research focuses on improving the quality of learning environments through uniform, soft, and diffused lighting, which mimics sky-like illumination while adhering to sustainable energy practices. Advanced asymmetric lens LED luminaires are employed to achieve optimal lighting distribution, as indicated by luminous intensity distribution curves. Comparative analyses in diverse educational settings reveal significant improvements in ceiling illuminance, ranging from 935 to 1000 lx, and workspace illuminance from 660 to 720 lx, with reduced glare (UGR < 10). This results in bright, visually comfortable spaces conducive to learning. Additionally, the PAL and BAL solutions outperform conventional lighting systems like stretched ceilings and lightboxes by maintaining clear overhead spaces, eliminating shadows, and offering cost-effective solutions. This successful integration demonstrates a notable advancement in the development of energy-efficient, visually comfortable educational environments, contributing to the goals of sustainability and improved well-being for both students and teachers.

Modeling epithelial-mesenchymal transition in patient-derived breast cancer organoids.

Cellular plasticity is enhanced by dedifferentiation processes such as epithelial-mesenchymal transition (EMT). The dynamic and transient nature of EMT-like processes challenges the investigation of cell plasticity in patient-derived breast cancer models. Here, we utilized patient-derived organoids (PDOs) as a model to study the susceptibility of primary breast cancer cells to EMT. Upon induction with TGF-β, PDOs exhibited EMT-like features, including morphological changes, E-cadherin downregulation and cytoskeletal reorganization, leading to an invasive phenotype. Image analysis and the integration of deep learning algorithms enabled the implantation of microscopy-based quantifications demonstrating repetitive results between organoid lines from different breast cancer patients. Interestingly, epithelial plasticity was also expressed in terms of alterations in luminal and myoepithelial distribution upon TGF-β induction. The effective modeling of dynamic processes such as EMT in organoids and their characteristic spatial diversity highlight their potential to advance research on cancer cell plasticity in cancer patients.

Analysis of irradiation in OptiTouch system with optical detection

As part of the research and development project, a multi-touch multimedia system was implemented, working exclusively on the basis of optical technologies. The model of device with a diagonal of 42” was developed and made with 4K TV image technology and simultaneous detection in near infrared. The control of individual system modules was carried out on RaspberryPi microcomputers without typical operating system. The functionality of a conventional large-format display with unlimited multi-touch, QR code scanner, and a document scanner has been achieved in one housing. Luminance distribution tests were carried out in accordance with ANSI requirements and infrared radiation for detection work.

Performance assessment of data-driven models for sky luminance prediction in Indian tropical climate

The precise prediction of sky luminance distribution is inevitable for design of efficient daylighting systems. The lack of measured sky luminance data in developing countries like India makes the current standard design sky models redundant. Most of the designer use Perez sky model for prediction of sky luminance distribution using solar insolation conditions for such locations. Data-driven models using machine learning can be a possible solution for prediction of sky luminance distribution in such locations. The present study compares the prediction accuracy of such data-driven models using four different machine learning techniques and compares the results Perez sky model. It becomes clear from the results that the data-driven model does not perform well when the location is different from the training dataset location, and the Perez sky model gives better results for such cases.

Generation of mouse testicular organoids with highly compartmentalized tubular lumen structure and their cryopreservation

Testicular organoids have great potential for maintaining male fertility and even restoring male infertility. However, existing studies on generating organoids with testis-specific structure and function are scarce and come with many limitations. Research on cryopreservation of testicular organoids is even more limited, and inappropriate cryopreservation methods may result in the loss of properties in resuscitated or regenerated organoids, rendering them unsuitable for clinical or research needs. In this paper, we investigated the effects of mouse age and cell number on the self-aggregation of testicular cells into spheres in low-adsorption plates. Various media compositions, culture systems, and cell numbers were used to culture cell spheres for 14 days to form testicular organoids, and the self-organization of the organoids was assessed by histological and immunofluorescence staining. We determined the appropriate cryopreservation conditions for testicular cells, cell spheres, and tissues. Subsequently, organoids derived from cryopreserved testicular tissues, testicular cells, and testicular cell spheres were compared and evaluated by histological and immunofluorescence staining. The results indicate that testicular cell spheres consisting of 30 × 104 testicular cells from 2-week-old mice were able to form organoids highly similar to the luminal structure and cell distribution of natural mouse testicular tissues. This transformation occurred over 14 days of incubation in α-MEM medium containing 10 % knockout serum replacer (KSR) using an agarose hydrogel culture system. Additionally, the Sertoli cells were tightly connected to form a blood-testis barrier. The relative rates of tubular area, germ cells, Sertoli cells, and peritubular myoid cells were 36.985 % ± 0.695, 13.347 % ± 3.102, 47.570 % ± 0.379, and 27.406 % ± 1.832, respectively. The optimal cryopreservation protocol for primary testicular cells involved slow freezing with a cryoprotectant consisting of α-MEM with 10 % dimethyl sulfoxide (DMSO). Slow freezing with cryoprotectants containing 5 % DMSO and 5 % ethylene glycol (EG) was optimal for all different volumes of testicular cell spheres. Compared to testicular organoids generated from frozen testicular tissue and cell spheres, freezing testicular cells proved most effective in maintaining organoid differentiation characteristics and cell-cell interactions. The findings of this study contribute to a “universal” testicular organoid in vitro culture protocol with promising applications for fertility preservation and restoration in prepubertal cancer patients and adult infertile patients.

A comparative study of machine learning methods for identifying the 15 CIE standard skies

For energy-efficient building designs, the solar irradiance and daylight illuminance derived from the CIE standard skies are useful. Over time, the sky luminance distributions have been used to identify these standard skies, but these are sparingly measured. Thus, the use of available climatic variables has become a viable alternative. Nevertheless, it is necessary to determine if these climatic variables could correctly identify these skies. This study addresses the lack of luminance distribution measurement by classifying the standard skies using measured climatic data in Hong Kong. The classification approach was improved by using the machine learning (ML) method. For comparative analysis, five popular ML classification algorithms i.e., decision tree (DT), k-nearest neigbhour (KNN), light gradient boosting machine (LGBM), random forest (RF) and support vector machines (SVM) were used. The findings show that accuracies of 68.1, 73.1, 74.3, 74.5, and 75.4% were obtained for the DT, KNN, SVM, LGBM, and RF models, respectively. Similarly, the F1 scores were 66.6, 70.2, 71.8, 72.1 and 72.9%, for the DT, KNN, SVM, LGBM, and RF models. The result shows that the RF model gave the best performance while DT performed the least. Also, the obtained accuracies and F1 scores show that all models would classify the standard skies with reasonable accuracy. Furthermore, feature importance was done, and it was found that Kd, Tv, Kt, α, sun, and cld are the most important input parameters for sky classification. Lastly, vertical solar irradiance ( GVT) and illuminance ( GVL) were estimated using the skies predicted by the proposed models. Upon predictions, it was observed that the GVT ranged from 14.7 to 24.6% while the GVL from 13.8 to 19.9%. Generally, most of the predictions were less than 20%, which shows good predictions were obtained from the models.

2D5-1 The effect of desk surface luminance distribution with task and ambient lighting on visual comfort

2D5-1 The effect of desk surface luminance distribution with task and ambient lighting on visual comfort

Assessment of the visibility of unprotected road users in pedestrian crossing

The article presents selected results of research on improving pedestrian traffic safety. Based on annually-updated accident statistics made available by the police, as well as the new pedestrian traffic regulations in force, detailed work was undertaken to assess the level of visibility of pedestrians by drivers in pedestrian crossing areas. The research was carried out by analyzing several characteristic cases of pedestrian crossings occurring in Poland, in which there was only dedicated lighting for crossings, only street lighting, and a variant of coexistence of both of the above lighting solutions. Illuminance measurements were made in the horizontal and vertical planes of pedestrian crossings, and the results were confronted with the relevant guidelines. The next step involved a complementary measurement of the luminance distribution of the vertical plane containing the pedestrian and a portion of the sub- and super-horizontal background. Visibility pedestrians was considered in positive and negative contrast variants, and was then related to the obtained results of the illumination distribution. The analysis of the results of the study indicated the possibility of limited visibility of pedestrians at the crossings despite the satisfactory results obtained from measurements of the illuminance distribution within the crossings.

Analysis of the General Index of Modelling in Interior Lighting

Directionality of light and modelling effects impact lighting quality in interiors. The modelling effects depend on luminaires’ photometric characteristics and their layout but also on interior size and reflectance. The objective of this research was to evaluate lighting design limitations and impact of interior and luminaires’ characteristics on the modelling effects, as well as elaborate a prediction method of the modelling effects in interior lighting. The General Index of Modelling was used for the analysis of the modelling effects in interiors. The implementation of the research objectives was based on the simulation and statistical analysis. 432 situations, varied interior size and reflectance, lighting class, luminaire downward luminous intensity distribution and layout were considered. The results show that achieving the required range of the General Index of Modelling in interior lighting is substantially limited. Luminaires’ layout impacts the General Index of Modelling the most. The elaborated multiple linear regression models can have a practical use for interior lighting design and analysis in terms of obtaining therequired range of the General Index of Modelling.

Visual comfort and energy savings in classrooms using surveillance camera derived HDR images for lighting and daylighting control system

Classroom lighting significantly influences students’ performance and productivity, as well as building energy consumption. Numerous studies highlight prevalent suboptimal lighting in education, with almost half of students expressing discomfort, emphasizing the need to enhance lighting environments. To address the issues mentioned and accommodate diverse learning activities with varying lighting needs and equipment, this paper introduces an innovative HDRi Surveillance Lighting Control System (HSLDCS). An experimental study investigates the implementation of the HSLDCS in ten classrooms with various learning activities. High Dynamic Range image (HDRi) photography is employed to assess lighting quality using the HDRi spatial luminance distribution, DGP and UGR, while a questionnaire survey is conducted to evaluate student well-being. Despite limitations regarding the adjustment time for window blinds and lamps, the results demonstrate that the adoption of appropriate HSLDCS can yield energy savings ranging from approximately 43%–63%, while still ensuring visual comfort for the majority of students. Over 70% of the students expressed satisfaction, even when classroom brightness was reduced by 30%. Considering the widespread use of laptops or tablets by students during class, reducing brightness levels is as a viable strategy for conserving energy and preventing visual fatigue. The implementation of the HSLDCS is a promising solution for alleviating suboptimal lighting conditions, enhancing energy efficiency, and promoting user well-being. This study also creates new opportunities for further exploration in the field of lighting technology and emphasizes the importance of prioritizing perceived brightness over illuminance.

Mapping Colorectal Distribution of Cell-free and Cell-associated HIV Surrogates Following Simulated Anal Intercourse to Aid Rectal Microbicide Development.

Anal sex remains the greatest HIV transmission risk for men who have sex with men and carries substantial population attributable risk among women. Despite a growing array of HIV pre-exposure prophylaxis (PrEP) options, rectal microbicides remain desirable as on demand, non-systemic PrEP. Rectal microbicide product development for PrEP requires understanding the spatiotemporal distribution of HIV infectious elements in the rectosigmoid to optimize formulation development. Outpatient setting with healthy research participants. Six healthy men underwent simulated receptive anal sex with an artificial phallus fitted with a triple lumen catheter in the urethral position. To simulate ejaculation of HIV-infected semen, autologous seminal plasma laden with autologous blood lymphocytes from apheresis labeled with 111Indium-oxine (cell-associated) and 99mTechnetium-sulfur colloid (cell-free) as HIV surrogates were injected into the rectal lumen through the phallic urethra. Spatiotemporal distribution of each radioisotope was assessed using SPECT/CT over eight hours. Analysis of radiolabel distribution used a flexible principal curve algorithm to quantitatively estimate rectal lumen distribution. Cell-free and cell-associated HIV surrogates distributed to a maximal distance of 15 and 16 cm, respectively, from the anorectal junction (∼19 and ∼20 cm from the anal verge), with a maximal signal intensity located 6 and 7 cm, respectively. There were no significant differences in any distribution parameters between cell-free and cell-associated HIV surrogate. Cell-free and cell-associated HIV surrogate distribution in the rectosigmoid can be quantified with spatiotemporal pharmacokinetic methods. These results describe the ideal luminal target distribution to guide rectal microbicide development.

Efficacy and Safety of an Autologous Micrografting Procedure for Management of Striae Distensae in Women.

Striae distensae (SD), or stretch marks, are a common skin problem having a psychological impact and cosmetic concern, especially for women, in whom the prevalence is higher than in men. This study assessed the efficacy and safety of a single autologous micrografting treatment (AMT®) using Rigenera® technology for the management of SD. This single-centre study included 10healthy women between 24 and 65years of age, with Fitzpatrick-Goldman skin typesI-IV, who had visible SD in glutes/thighs. Each subject acted as their own control. The treatment procedure (microneedling + AMT) and the control procedure (no treatment) were performed on contralateral sides of the glutes/thighs, targeting matched and paired SD. Microneedling was carried out using Dermapen®, equipped with 32 needle heads set at 1.5mm needle length. The AMT procedure involved extracting biopsies from the mastoid hair zone with a 2.5-mm dermal punch, followed by disaggregation of the biopsies in a physiological saline solution using the Rigeneracons. The disaggregated micrografts were then intradermally injected using 30G 4-mm needles, maintaining a distance of 1cm between injection points, covering the entire marked treatment region. In the treated area, at 3months post-procedure compared to pre-procedure, the following changes were observed, all with statistical significance (P ≤ 0.05): (a) significant reductions in skin roughness (Ra, - 15.9%; Rz, - 22.6%), skin luminance (- 2.0%), and blue-green color distribution (- 10.6%); (b) significant increases in skin microcirculation maximum value (+ 240.1%), skin hydration (+ 71.2%), skin elasticity (+ 216.5%), skin density (+ 34.3%), skin thickness (+ 26.0%), and hypodermis thickness (+ 29.9%). Furthermore, for each of the aforementioned parameters, there was a significantly greater improvement observed with the AMT procedure compared with microneedling at 3months (all P ≤ 0.05). The AMT procedure using Rigenera technology resulted in an noticeable improvement in the SD appearance after 3months in healthy women.

Influence of the reflector properties on the photometric characteristics of a luminaire with variable luminous intensity distribution

Influence of the reflector properties on the photometric characteristics of a luminaire with variable luminous intensity distribution

Evacuation route design based on visibility for reducing evacuation delays

With the improvement of fire prevention technology and legislation, the number of fires has been decreasing year by year in Japan. Nevertheless, nearly half of fire-related fatalities are caused by delayed evacuation. For rapid evacuation from hazardous areas to safety, it is important to improve the visual environment of evacuation routes. The current paper describes the scientific basis for establishing effective safety evacuation countermeasures and relevant behaviors regarding evacuees’ vision during fires. First, the basics of visibility are explained. The role of luminance as a photometric quantity related to visibility is discussed, and a visibility evaluation method is presented. Regarding human behavior related to visibility, the legibility of characters and walking speed are explained based on previous research. Additionally, visibility in fire smoke is discussed, including smoke adhesion and luminance distribution, as well as walking speed and psychological state in smoke. On the basis of this analysis, evacuation route design is discussed in relation to visibility for reducing evacuation delays.

Laboratory Assessment of In-Pavement Airport Lamp’s Luminous Intensity Distribution

The luminous intensity measurements of airport navigational lighting should be performed in accordance with the recommendations of the European Aviation Safety Agency (EASA), which allows for the determination of the possibility of further operation or the need to replace particular lamps. This article presents a device and method for measuring the light main beam of in-pavement airport lamps used on runways and taxiways. During the measuring process in the laboratory dark room, the proposed system automatically prepares reports as heatmaps presenting angular relationships of light distribution. Photometric measurements were made using a BH1750 illuminance sensor, which was compared to a certified Sonopan L-200P luxmeter. The measurement stability of different BH1750 modes was investigated for different airport lamp power source thresholds. Due to distortions in spectral characteristic of BH1750, polynomial corrections were proposed. The functionality of the device was presented for the exemplary assessment of used and refurbished runway in-pavement airport lamps to compare their parameters change. The research results and device implementation were possible through scientific cooperation with the Poznań-Ławica Airport.

A phenomenological model of non-genomic variability of luminescent bacterial cells

The light emitted by a luminescent bacterium serves as a unique native channel of information regarding the intracellular processes within the individual cell. In the presence of highly sensitive equipment, it is possible to obtain the distribution of bacterial culture cells by the intensity of light emission, which correlates with the amount of luciferase in the cells. When growing on rich media, the luminescence intensity of individual cells of brightly luminous strains of the luminescent bacteria Photobacterium leiognathi and Ph. phosporeum reaches 104–105 quanta/s. The signal of such intensity can be registered using sensitive photometric equipment. All experiments were carried out with bacterial clones (genetically homogeneous populations). A typical dynamics of luminous bacterial cells distributions with respect to intensity of light emission at various stages of batch culture growth in a liquid medium was obtained. To describe experimental distributions, a phenomenological model that links the light of a bacterial cell with the history of events at the molecular level was constructed. The proposed phenomenological model with a minimum number of fitting parameters (1.5) provides a satisfactory description of the complex process of formation of cell distributions by luminescence intensity at different stages of bacterial culture growth. This may be an indication that the structure of the model describes some essential processes of the real system. Since in the process of division all cells go through the stage of release of all regulatory molecules from the DNA molecule, the resulting distributions can be attributed not only to luciferase, but also to other proteins of constitutive (and not only) synthesis.

Method for Calculating the Asymmetric Luminous Intensity Distribution for the Road Lighting Luminaire

A method is proposed for calculating the asymmetric luminous intensity distribution of a luminaire for stationary road lighting, in which the properties of directional reflection of light from the road surface are used to the greatest extent. The method is based on the analytical relationship of the luminaire’s luminous intensity in the direction of the calculated point with the luminance of the road surface at this point in the direction of the driver, expressed in terms of the reduced luminance coefficient of this coating. The main provisions and algorithm of the method are given. The features of the calculation depending on the angle of inclination of the luminaire and the layout of the luminaires relative to the direction of movement are shown. According to a specially developed computer program, an example of calculating the asymmetric light distribution of a luminaire is executed and its effectiveness is evaluated in comparison with traditional symmetrical luminous intensity distribution.

Off-axis limiting photometric distance of Lambertians and narrow beams

The near-field - far-field disparity of light sources leads to discussion within the lighting community. In the far-field, light sources are approximated by a point source with a luminous intensity distribution from which other photometric quantities can be computed. In the near-field, light sources must be considered as extended sources and no closed-loop analytical solutions can be found for the illuminance in off-axis directions. The illuminance allows to compute the apparent intensity used for the assessment of the limiting photometric distance (LPD), that is, the threshold between near- and far-field regions. Numerically, the illuminance can be determined through a discretisation of the luminous surface. This approach is verified for on- and off-axis directions through direct comparison with ray tracing simulations based on near-field goniophotometric measurements. A good match is observed for Lambertian and narrow beam light sources. Using the numerical approach, the LPD in all directions is assessed. For light sources of which the luminous intensity strictly decreases while moving away from the optical axis, the LPD decreases as well until a minimal value is reached. After this, the LPD increases again, in certain scenarios up to values resulting in the invalidity of the inverse square law.

Bifurcation and Transposition of the Wicking Front of Binary Solutions Infiltrating into Chromatography Paper Associated with Their Evaporation.

Nonequilibrium fluid patterns, such as Marangoni contraction, coffee rings, and tears of wine, are generated in binary solutions spread on a substrate during their evaporation. In this study, we observed another type of nonequilibrium behavior exhibited by binary solutions as they infiltrate porous materials and undergo evaporation. A binary solution comprising hexane and ethanol was brought into contact with the chromatography paper to facilitate infiltration into the paper's pores. Because the experimental setup was in an open environment, infiltration and evaporation occurred simultaneously. The wicking front exhibited an initial rapid advancement, followed by subsequent receding and readvancing. Additionally, the bifurcation of the wicking front after the onset of its readvancement was confirmed by monitoring the temporal evolution of the spatial luminance distribution and temperature distribution on the surface of the chromatography paper. Chromatographic development of a hydrophilic dye was conducted in this experimental setup in an open environment. Additionally, it was confirmed that the receding and readvancing of the wicking front represented the transposition of the bifurcated wicking fronts.

Determination of light direction and efficiency criterias of plexiglass diffusion light

In this study, it is aimed to determine the light direction and efficiency criteria of plexiglass diffused light sources. Within this scope, linear slots were opened in plexiglass and these slots' distances were shifted in order to analyze luminous flux, luminous intensity distribution and their effects on luminaire's efficiency. In this study the evaluations were examined in accredited laboratory with goniophotometer. As a result of the measurements, it was observed that slots in the plexiglass and distance changes in between these affect the lighting values of light source. By using these effects and the distance between the slots, a mathematical model was created with the least-square method. In this study, it was concluded that the luminous efficiency of the lighting luminaire is not only related to the light source, but also the light source that used in the luminaire is directed towards the area to be illuminated properly.