Simple Light Research Articles

Therapeutic effect of Micro-Implant Anchorage in orthodontics

Objective: Micro implant anchorage (MIA), as a new orthodontic treatment technique, has the characteristics of simple operation, light trauma, and high stability, and has been widely used in clinical practice. This study compared the therapeutic effects of MIA and the traditional straight wire appliance (SWA) in orthodontic practice. Methods: Clinical data of 119 patients who underwent orthodontic treatment in Yulin First Hospital from January 2022 to January 2023 were retrospectively analyzed. According to the treatment records, 61 patients received MIA orthodontic treatment (MIA group), and 58 patients received traditional straight wire appliance (SWA) orthodontic treatment (SWA group). Treatment effect, periodontal index, and levels of osteoprotegerin (OPG), interleukin-6 (IL6) and high-sensitivity C-reactive protein (hsCRP) of the two groups were compared. Results: The total efficacy of MIA group was significantly higher than that of SWA group (P<0.05). After the treatment, bleeding index (BI), plaque index (PLI), probing depth (PD) and looseness in the MIA group were significantly lower than those in the SWA group (P<0.05). After the treatment, levels of OPG were significantly higher, while IL6 and hsCRP levels were significantly lower in the MIA compared to the SWA group (P<0.05). MIA was associated with significantly lower complication rate compared to the SWA (P<0.05). Conclusions: Compared with SWA, MIA is associated with better orthodontic effect. This mode of treatment can increase OPG levels, reduce inflammation, and lower the risk of complications. doi: https://doi.org/10.12669/pjms.40.10.10442 How to cite this: Shi Y, Mi L, Liu J, Liu X, Hao Y. Therapeutic effect of Micro-Implant Anchorage in orthodontics. Pak J Med Sci. 2024;40(10):2293-2298. doi: https://doi.org/10.12669/pjms.40.10.10442 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Multi-stage and multi-colour liquid crystal reflections using a chiral triptycene photoswitchable dopant.

The photomodulation of the helical pitch of cholesteric liquid crystals results in dynamic and coloured canvases that can potentially be used in applications ranging from energy-efficient displays to colour filters, anti-counterfeiting tags and liquid crystal (LC) lasers. Here we report on the analysis of a series of photoswitchable chiral dopants that combine the large geometrical change and bistability of hydrazone switches with the efficient helical pitch induction of the chiral motif, triptycene. We elucidate the effects that conformational flexibility, dispersion forces and π-π interactions have on the chirality transfer ability of the dopant. We then use the irradiation time with visible light (442 nm) combined with a simple digital light processing microscope projection set-up to draw numerous stable multi-coloured images on an LC canvas, showcasing the fine control this dopant yields over the LC assembly.

Automated counting and classifying Daphnia magna using machine vision

Daphnia magna (D. magna) is a model organism widely used in aquatic ecotoxicology research due to its sensitivity to environmental changes. The survival and reproduction rates of D. magna are easily affected by toxic environments. However, their small size, fragility, and transparency, especially in neonate stages, make them challenging to count accurately. Traditionally, counting adult and neonate D. magna relies on manual separation and visual observation, which is not only tedious but also prone to inaccuracies. Previous attempts to aid counting with optical sensors have faced issues such as inducing stress damage due to vertical movement and an inability to distinguish between adults and neonates. With the advancement of deep learning technologies, our study employs a simple light source culture device and utilizes the Mask2Former model to analyze D. magna against the background. Additionally, the U-Net model is used for comparative analysis. We also applied OpenCV technology for automatic counting of adult and neonate D. magna. The model's results were compared against manual counting performed by experienced technicians. Our approach achieves an average relative accuracy of 99.72 % for adult D. magna and 98.30 % for neonate. This method not only enhances counting accuracy but also provides a fast and reliable technique for studying the survival and reproduction rates of D. magna as a model organism.

Development of multi-view 3D reconstruction system for bubble flow measurement

This work introduces the development of bubble measurement method utilizing a three-dimensional (3D) reconstruction technique from multi-view images. Multiple synchronized cameras were positioned around a water container, and calibration was performed to obtain external and internal camera parameters. Images of bubbles emerging from a nozzle were captured, and a machine learning technique was used to extract bubble silhouettes as foreground probability distributions, enabling the extraction of bubbles from images obtained with a simple lighting setup. These distributions were then projected onto a 3D voxel space using the visual hull method. It was confirmed that the method can successfully capture bubble generation, detachment, and rise behaviors, offering insights into understanding bubble dynamics and potential applications in 3D computational fluid dynamics validation.

Edge-Light: Exploiting Luminescent Solar Concentrators for Ambient Light Communication

A recent advance in embedded Internet of Things (IoT) exploits ambient light for wireless communication. This new paradigm enables highly efficient links via simple light modulation, but the design space has a fundamental constraint: in most State of the Art (SoA) studies, the link can only follow the propagation direction of ambient light. Consider, for example, a swarm of drones and ground robots that want to communicate with sunlight. Drone-to-robot communication could be possible because sunlight travels downwards from the air (drone) to the ground (robot), allowing drones to modulate light to send information to robots beneath them. Robot-to-robot communication, however, is not possible because sunlight does not travel sideways (parallel to the ground). To allow 'lateral communication' with ambient light, we propose using Luminescent Solar Concentrators (LSC). These optical components receive ambient light on their surface and re-direct part of the spectra towards their edges. Considering this optical property of LSC, our work has three main contributions. First, we benchmark various optical properties of LSC to assess their performance for ambient light communication. Second, we combine LSC with liquid crystal (LC) shutters to form lateral links with ambient light. Third, we test our links indoors and outdoors with artificial and natural ambient light, by enhancing two robots with our LSC transceivers and showing that they can exchange basic commands and coordinate tasks by communicating only with sunlight.

Nitrogen-Doped Carbon Quantum Dots with Photoactivation Properties for Ultraviolet Ray Detection.

Photoactivation is a phenomenon that could enhance the photoluminescence (PL) and photostability upon UV/vis light exposure, which is usually observed in CdSe/ZnS quantum dots (QDs). However, the photoactivation phenomenon has been scarcely reported in fluorescent carbon quantum dots (CQDs). Herein, the nitrogen-doped carbon quantum dots (N-CQDs) were prepared through a facile solvothermal approach with naphthalenetracarboxylic dianhydride and serine as precursors. Upon simple UV light irradiation for 10 min, the fluorescence quantum yield (QY) of N-CQDs could increase up to 10-fold. Based on this phenomenon, the N-CQDs were explored as an ultraviolet (UV) light sensor to assess the intensity of ultraviolet radiation in sunlight and indirectly evaluate the UV-blocking efficiency of various sunscreen products. Thus, this contribution not only provided an insight into developing a low-cost UV detector but also opened a door for the development of carbon quantum dots with converse-photobleaching properties.

Human-centred physical neuromorphics with visual brain-computer interfaces

Steady-state visual evoked potentials (SSVEPs) are widely used for brain-computer interfaces (BCIs) as they provide a stable and efficient means to connect the computer to the brain with a simple flickering light. Previous studies focused on low-density frequency division multiplexing techniques, i.e. typically employing one or two light-modulation frequencies during a single flickering light stimulation. Here we show that it is possible to encode information in SSVEPs excited by high-density frequency division multiplexing, involving hundreds of frequencies. We then demonstrate the ability to transmit entire images from the computer to the brain/EEG read-out in relatively short times. High-density frequency multiplexing also allows to implement a photonic neural network utilizing SSVEPs, that is applied to simple classification tasks and exhibits promising scalability properties by connecting multiple brains in series. Our findings open up new possibilities for the field of neural interfaces, holding potential for various applications, including assistive technologies and cognitive enhancements, to further improve human-machine interactions.

One-step light-induced hierarchical surface wrinkles on photodegradable polymer films

Photodegradable polymers have become an emerging class of stimulus-sensitive materials for advanced applications, in which using the photolysis characteristic for patterning surface is a key but still a notable challenge. Herein, we report a simple, facile, green and high-efficiency strategy to induce and further tune surface wrinkling only relying on one-step ultraviolet (UV) irradiation of a photodegradable polymer-based film/substrate composite system. Interestingly, a series of intriguing wrinkling states from no wrinkling to surface wrinkling and final no wrinkling with UV exposure take place on the photodegradable polymer film. This wrinkling behavior is intimately related to the competition between the stress accumulation from the heating effect of UV lamp itself and the stress release from the UV-induced molecular chain breakage. Meanwhile, the dependence of photodegradable polymer film modulus and photodegradation-induced stress release on the exposure time has been characterized by taking advantage of surface wrinkling metrology, which is not easily accessible to other systems and methods. This one-step light irradiation strategy has enabled the fabrication of diverse hierarchical surface wrinkling on photodegradable polymer film by simply controlling the UV exposure time. As demonstrated, these hierarchical surface wrinkles with tunable features have been applied for optical information display/storage and optical gratings. Notably, this simple flexible light control strategy not only provides new insights into the photo-induced change in mechanical properties and stress release of photodegradable polymers in molecular level, but also paves new avenues for advanced wrinkle-based applications by incorporating desirable functional materials into the photodegradable polymer-based systems.

The learning activities of RBL-STEM: Prototyping a water-powered lamp to enhance students' climate change literacy

Addressing climate change and the finite nature of fossil fuels necessitates proactive solutions, one of which is embedding climate change literacy within educational frameworks. This form of literacy aims to equip students with a comprehensive understanding of the concepts, causes, impacts, and potential solutions related to climate change. An educational approach that integrates these elements is the RBL-STEM learning model, particularly through the study of Renewable Energy. For instance, students engage in practical activities like constructing simple water-powered lights, which helps con textualize energy availability issues. This developmental research employed the 4D model to create and refine teaching modules, student worksheets (LKPD), and assessments for climate change literacy. The effectiveness of these materials was evaluated with a cohort of 25 fourth-grade students at SDN Tenggilis Mejoyo I in Surabaya. The findings indicated that the RBL-STEM learning resources related to Renewable Energy were well-designed, effective, and suitable for educational use. Importantly, they significantly enhanced the students' understanding and literacy regarding climate change, demonstrating the value of integrating hands-on, practical learning experiences in the curriculum to foster a deeper awareness and knowledge of renewable energy and climate-related issues.

Unveiling lens light complexity with a novel multi-Gaussian expansion approach for strong gravitational lensing

ABSTRACT In a strong gravitational lensing system, the distorted light from a source is analysed to infer the properties of the lens. However, light emitted by the lens itself can contaminate the image of the source, introducing systematic errors in the analysis. We present a simple and efficient lens light model based on the well-tested multi-Gaussian expansion (MGE) method for representing galaxy surface brightness profiles, which we combine with a semi-linear inversion scheme for pixelized source modelling. Testing it against realistic mock lensing images, we show that our scheme can fit the lensed images to the noise level, with relative differences between the true input and best-fitting lens light model remaining below 5 per cent. We apply the MGE lens light model to 38 lenses from the HST SLACS sample. We find that the new scheme provides a good fit for the majority of the sample with only 3 exceptions – these show clear asymmetric residuals in the lens light. We examine the radial dependence of the ellipticity and position angles and confirm that it is common for a typical lens galaxy to exhibit twisting non-elliptical isophotes and boxy / disky isophotes. Our MGE lens light model will be a valuable tool for understanding the hidden complexity of the lens mass distribution.

Beyond ExaBricks: GPU Volume Path Tracing of AMR Data

AbstractAdaptive Mesh Refinement (AMR) is becoming a prevalent data representation for HPC, and thus also for scientific visualization. AMR data is usually cell centric (which imposes numerous challenges), complex, and generally hard to render. Recent work on GPU‐accelerated AMR rendering has made much progress towards real‐time volume and isosurface rendering of such data, but so far this work has focused exclusively on ray marching, with simple lighting models and without scattering events or global illumination. True high‐quality rendering requires a modified approach that is able to trace arbitrary incoherent paths; but this may not be a perfect fit for the types of data structures recently developed for ray marching. In this paper, we describe a novel approach to high‐quality path tracing of complex AMR data, with a specific focus on analyzing and comparing different data structures and algorithms to achieve this goal.

A simple light path modifying device to reduce scattering in front-face fluorescence spectra.

This technical note presents a device to diminish scattering signal in front-face fluorescence spectra while obtaining fluorescence signal. The beam path in a commercial fluorescence spectrometer was modified by two deflecting mirrors, leading reflections away from the sensor. This light path modifying (LPM) device was tested with two fluid and three solid substances, where the scattering-to-fluorescence ratio improved by a factor of 1.7 to 7.6. The spectra obtained with the LPM were much clearer, and distortion of the fluorescence peaks was avoided. Scans of quinine sulphate complied well with reference spectra.&#xD.

Novel effective spectrum broadening technology pumped by 2 μm picosecond laser for mid-infrared supercontinuum generation

Using thulium-doped fiber laser to pump fluoride fiber is one of the most common methods to generate mid-infrared supercontinuum (SC). But it is difficult to generate SC spectrum with wavelength more than 4 μm by directly pumping short fluoride fiber with 2 μm picosecond (ps) laser. Although some studies with SC exceeding 4 μm have also been reported, the proportion of spectral power in the long-wavelength region is not very high. To address this issue, a novel and simple approach to solve low peak power of 2 μm ps pump sources is introduced by adding a short piece of holmium-doped fiber. This method can make full use of the gain bandwidth of Ho3+ and soliton self-frequency shift effect to enhance soliton energy and promote spectral broadening. The effectiveness of the approach is verified by constructing a theoretical model to solve the generalized nonlinear Schrödinger equation. We demonstrate through simulations that addition of holmium-doped fiber can yield significantly improved output spectral range, power ratio in the long-wavelength region and optical–optical conversion efficiency compared to the previous technical. Especially, the implementation of the new technology can effectively expand the SC long-wavelength edge by ∼470 nm after applying a 3 dB gain, and can easily build a simple, compact and low-cost mid-infrared light source system.

The Polysemic Comedy of Too Busy to Work

ABSTRACT This article examines cultural, narrative and stylistic features of Too Busy to Work, a 1932 film starring Will Rogers. While, on the surface, the movie could be seen as a simple light comedy about the travelogue of a hobo name Jubilo, close examination reveals a tragicomedy interested in issues of justice, marriage, political parody, food, money, work, and a Civil War era song that is used both as a personal identity marker and an illustration of the general complexities of race in the United States. Too Busy to Work instead leads the careful critic to a complex visual text that asks unanswerable social questions. Thus, the film should be studied and remembered as interesting, unusual, and complex.

Genetically Encoded Lysine Analogues with Differential Light Sensitivity for Activation of Protein Function

AbstractGenetically encoded unnatural amino acids are versatile tools for controlling protein function, but options for regulating multiple proteins in a single experiment are limited. Here, we report the genetic encoding of two new photocaged lysine derivatives, 1‐(2‐nitrophenyl)‐ethyl lysine and nitrodibenzylfuranyl lysine, for sequential light‐activation of protein function in live cells. Nitrodibenzylfuranyl (NDBF) caging groups have a redshifted absorbance maximum and high sensitivity to light compared to the 1‐(2‐nitrophenyl)‐ethyl group (NPE), enabling selective decaging and protein activation. We characterized the responses of these new caged amino acids by optically triggering nuclear localization and firefly luciferase activity. The ability to selectively activate distinct proteins through simple light titration makes this a useful approach with broad applications.

Light one-electron molecular ions within the finite-basis-set method for the two-center Dirac equation

During the last decades outstanding results on the precision description of light diatomic molecular compounds have been achieved. The most advanced calculations of electron binding energies have been realized mainly in the framework of the nonrelativistic approach with a consistent account of relativistic and radiative QED corrections. Recently, it has been shown that methods based on the Dirac equation are also suitable for obtaining highly accurate results in simple light molecules. In this paper, we present a completely relativistic method and discuss its application to the description of diatomic systems. In particular, the electronic spectra of the light one-electron quasi-molecular compounds H-H+, He+-He2+ and He+-H+ are analyzed. For this purpose, the two-center Dirac equation is solved by a dual-kinetic balanced finite-basis-set method for axially symmetric systems, called A-DKB. This method allows for a complete relativistic consideration of the electron at fixed inter-nuclear distances. A comparison of the obtained results with the nonrelativistic and relativistic calculations presented in the literature is performed. Without pursuing the goal of high accuracy calculations, the advantages and disadvantages of the approach, as well as possible applications of the method, are discussed in detail.

Multicolor two-photon light-patterning microscope exploiting the spatio-temporal properties of a fiber bundle.

The development of efficient genetically encoded indicators and actuators has opened up the possibility of reading and manipulating neuronal activity in living tissues with light. To achieve precise and reconfigurable targeting of large numbers of neurons with single-cell resolution within arbitrary volumes, different groups have recently developed all-optical strategies based on two-photon excitation and spatio-temporal shaping of ultrashort laser pulses. However, such techniques are often complex to set up and typically operate at a single wavelength only. To address these issues, we have developed a novel optical approach that uses a fiber bundle and a spatial light modulator to achieve simple and dual-color two-photon light patterning in three dimensions. By leveraging the core-to-core temporal delay and the wavelength-independent divergence characteristics of fiber bundles, we have demonstrated the capacity to generate high-resolution excitation spots in a 3D region with two distinct laser wavelengths simultaneously, offering a suitable and simple alternative for precise multicolor cell targeting.

Resolving the Periods of the Asynchronous Polar 1RXS J083842.1–282723

1RXS J083842.1−282723 is a nearly synchronous magnetic cataclysmic variable with a simple X-ray light curve. While its orbital period was fairly well established at P orb = 98.4 minutes from optical spectroscopy, indirect estimates of P spin/P orb ranged from 0.90 to 0.96 because the short X-ray light curves could not determine the beat period to a factor of 2. We analyze a recent 50 days TESS observation, and ground-based optical time-series photometry spanning 9 yr, that together measure precise beat, orbit, and spin periods and enable the X-ray and optical modulations to be phase aligned. Although the X-ray light curves do not distinguish between a beat period of 16.11 or 32.22 hr, all of the optical evidence favors the longer value, with complete pole switching of accretion every half beat cycle. This would require P spin/P orb = 0.952. Long-term optical monitoring also shows a decline in accretion rate, and a change in the beat-folded light curve. It would be useful to obtain a new X-ray/optical observation of at least 32 hr duration to examine any associated change in accretion structure, and to confirm the spin and beat periods.

Circadian rhythm and whole gut transit in mice.

In preclinical studies whole gut transit (WGT) in mice is a gold-standard "leading-edge" approach that measures the time between orogastric gavage of carmine red and defecation of the first carmine red pellet. Transit studies in humans are performed during the active day because GI motility and transit are suppressed during the night. Since mice are nocturnal, WGT studies traditionally done during the day occur during their rest phase. How circadian rhythm affects WGT in mice is not known. We used an automated approach for high temporal resolution uninterrupted testing of mouse WGT and activity. We housed wild-type Bl6/C57 mice under the standard 12 h light-dark cycles. At 8 weeks, we performed carmine red orogastric gavage and assessed WGT during Light (rest) conditions. Then, we exposed mice to a reverse 12 h light-dark cycle for 2 weeks and tested them in the Dark (active) under red light conditions. Timelapse videos were analyzed to quantify activity and to timestamp all pellets, and multiple parameters were analyzed. When complementary light cycle reversal experiments were performed, we found a significant increase in mouse activity when mice were tested during their Dark (active) phase, compared to their Light (rest) phase. In mice tested in the Active phase compared to the Rest phase, we found a significant acceleration in WGT, increased rate and total number of pellets produced, and more pellet clustering. These data show that the mice tested in the Active phase have important differences in activity that correlate with multiple alterations in gastrointestinal transit. During the Active phase mice have faster WGT, produce more pellets, and cluster their output compared to testing in the Rest phase. Like in humans, circadian rhythm is an important consideration for transit studies in mice, and a simple reverse light cycle approach facilitates further studies on the role of circadian rhythm in GI motility.

Real‐Time Polygonal Lighting of Iridescence Effect using Precomputed Monomial‐Gaussians

AbstractThe real world consists of mass phenomena, such as iridescence on thin film and metal oxide layers, that is only explicable by wave optics. Existing research can reproduce such effects with simple point lights or low‐frequency environmental lighting. However, it remains a difficult task to efficiently rendering these effects when near‐field, high‐frequency area lights are involved. This paper presents a high‐fidelity, real‐time rendering algorithm for the iridescence effect under polygonal lights. We introduce a novel set of spherical functions, Monomial‐Gaussians, to accurately fit iridescent materials' reflectance. With a precomputed lookup table, the Monomial‐Gaussians are easily integrated over spherical polygons in linear time. Importance sampling of Monomial‐Gaussians is also supported to efficiently reduce Monte‐Carlo error. Our approach produces accurate renderings of the iridescence effect while still preserving high frame rates.