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1.
Klin Monbl Augenheilkd ; 237(10): 1187-1193, 2020 Oct.
Artigo em Inglês, Alemão | MEDLINE | ID: mdl-33059378

RESUMO

In recent years, an increasing incidence of laser pointer-associated retinal injuries has been observed, likely due to easy access to incorrectly classified laser pointers, their labelling as toys, and lack of awareness concerning the associated risk. Laser pointer exposure can lead to irreversible retinal damage and associated vision loss, depending on the wavelength, radiation power, duration of exposure, localization, and spot size. Pronounced retinal laser damage is especially seen in children and teenagers. The structural appearance of retinal laser pointer damage varies and, in some cases, may be a diagnostic challenge. Besides often subtle findings on optical coherence tomography examination, characteristic alterations on near-infrared autofluorescence imaging may be valuable for the diagnosis of retinal laser pointer injuries and for differentiating other retinal lesions with similar appearance. The increase in laser pointer injuries indicates that regulatory actions and increased public awareness are required regarding the dangers of laser pointers.


Assuntos
Retina , Doenças Retinianas , Adolescente , Criança , Humanos , Lasers , Retina/diagnóstico por imagem , Doenças Retinianas/etiologia , Tomografia de Coerência Óptica , Acuidade Visual
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1911-1914, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018375

RESUMO

Photoacoustic imaging has shown its great potential in biomedical imaging. A variety of imaging applications, like blood oxygenation for functional imaging, have been widely studied during the past few decades. Most of the previous works are based on the tissue's endogenous or nanoprobe's extraneous optical absorbance. In this paper, we proposed frequency-domain dual-contrast photoacoustic imaging aiming at exploring both optical absorption and mechanical property (e.g., viscoelasticity) of tissue. Instead of conventionally used pulsed excitation, a chirp-modulated laser signal is used to excite the sample to induce photoacoustic signals. On one hand, the optical absorption contrast is obtained by cross-correlating the PA signals with the chirp pattern. On the other hand, mechanical property is obtained by performing the Fourier transform to analyze the frequency spectrum. Experimental results revealed that samples with higher density-to-viscoelasticity ratio show larger quality factor in the received PA signals' spectrum. Both theoretical analysis and experimental demonstrations are performed to prove the feasibility of the proposed method.


Assuntos
Técnicas Fotoacústicas , Testes Diagnósticos de Rotina , Lasers , Luz , Análise Espectral
3.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2245-2248, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018454

RESUMO

Recently, the study of communication in an 'Astrocyte Network' has been suggested to be of equal importance to that of the traditional 'Neural Network'. In this paper, for the first time, we use nanosecond laser stimulation to stimulate the central cell in an organized grid network of connected human astrocytes in order to observe calcium wave propagation at the single-cell level. We show that the calcium waves indeed propagate from the central astrocyte to the outer periphery of the organized astrocyte network. We observe also, like astrocytes in standard in vitro petri dishes, that the calcium wave propagates through specific connections to the outer periphery of cells rather than in a uniform radial manner predicted by mathematical theory. The results show that such a platform provides an excellent environment to perform repeatable, controlled studies of calcium wave signal propagation through an organized grid network of human astrocytes at single-cell resolution.


Assuntos
Astrócitos , Sinalização do Cálcio , Astrócitos/metabolismo , Cálcio/metabolismo , Humanos , Lasers
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3581-3585, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018777

RESUMO

Infrared neural stimulation (INS) is an optical stimulation technique which uses coherent light to stimulate nerves and neurons and which shows increased spatial selectivity compared to electrical stimulation. This could improve deep brain, high channel count, or vagus nerve stimulation. In this study, we seek to understand the wavelength dependence of INS in the near-infrared optical window. Rat sciatic nerves were excised ex vivo and stimulated with wavelengths between 700 and 900 nm. Recorded compound nerve action potentials (CNAPs) showed that stimulation was maximized in the 700 nm window despite comparable laser power levels across wavelengths. Computational models demonstrated that wavelength-based activation dependencies were not a result of passive optical properties. This data demonstrates that INS is both wavelength and power level dependent, which inform stimulation systems to actively target neural microcircuits in humans.


Assuntos
Raios Infravermelhos , Nervo Isquiático , Animais , Estimulação Elétrica , Lasers , Ondas de Rádio , Ratos
5.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(5): 525-531, 2020 Oct 01.
Artigo em Chinês | MEDLINE | ID: mdl-33085236

RESUMO

OBJECTIVE: The aim of this study is to treat calcified root canal and assess the accuracy of guided endodontics using laser melting templates. METHODS: Two cases with calcified anterior teeth were treated with laser melting templates. Cone beam computed tomography (CBCT) was used to scan the maxillary teeth of patients before surgery to establish the root canal system model. The maxillary impression of the patient was made and it was scanned by a 3D scanner. The CBCT scans were matched with surface scans of plaster model. Mimics 19.0 and 3-matic 11.0 software were used to design the virtual planning to access cavities. The templates were produced by laser melting 3D printing. Access cavity was prepared under the guidance of laser melting template. Then the deviations of planned and prepared cavities in three dimensions and angle were measured. RESULTS: The two teeth obtained satisfactory results. The first case had a angle deviation of 1.77°, a drilling base deviation of 0.403-0.497 mm, and a tip of 0.433-0.537 mm. The second case had a angle deviation of 3.26°, a drill base deviation of 0.18-0.347 mm, and a tip of 0.310-0.463 mm. CONCLUSIONS: Laser melting template-guided endodontics is an effective technique for the treatment of calcified root canal and can be used as a new strategy for the treatment of calcified canal.


Assuntos
Cárie Dentária , Endodontia , Cavidade Pulpar , Humanos , Lasers , Tratamento do Canal Radicular
7.
Chin J Dent Res ; 23(3): 183-189, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32974618

RESUMO

OBJECTIVE: To design and fabricate 3D-printed rigid constraint guides for the tooth preparation for laminate veneers and to evaluate the accuracy of guide-assisted preparation. METHODS: Twenty maxillary right central incisor resin artificial teeth were randomly divided into two equal groups and prepared for laminate veneers. Tooth preparations were performed, assisted by guides in the test group and by depth gauge burs in the control group, and both were finished by freehand operation. The typodonts were 3D scanned before preparation, after initial preparation and after final preparation. The tooth preparation depths at each step, including initial preparation depth, final preparation depth and loss of tooth tissue during polishing, were measured by 3D deviation analysis. Statistical analyses were conducted to investigate differences. RESULTS: The initial preparation depth was 0.488 mm (median, quartile 0.013 mm) in the test group and 0.521 mm (median, quartile 0.013 mm) in the control group. A statistically significant difference was found between them (P < 0.05). The final preparation depth in the test group (0.547 ± 0.029 mm) was significantly less than that in the control group (0.599 ± 0.051 mm) (P < 0.05), and closer to the predesigned value (0.5 mm). There was no statistically significant difference in the loss of tooth tissue during polishing between the test group (0.072 ± 0.023 mm) and the control group (0.089 ± 0.038 mm) (P > 0.05). CONCLUSION: In maxillary central incisors, the tooth preparation for laminate veneers could be conducted using 3D-printed rigid constraint guides, the accuracy of which is better than that of depth gauge burs.


Assuntos
Porcelana Dentária , Facetas Dentárias , Incisivo , Lasers , Preparo do Dente
8.
Science ; 369(6509): 1304-1305, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32913090
9.
Nat Commun ; 11(1): 4848, 2020 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-32973166

RESUMO

Polydopamine (PDA) is a simple and versatile conformal coating material that has been proposed for a variety of uses; however in practice its performance is often hindered by poor mechanical properties and high roughness. Here, we show that blue-diode laser annealing dramatically improves mechanical performance and reduces roughness of PDA coatings. Laser-annealed PDA (LAPDA) was shown to be >100-fold more scratch resistant than pristine PDA and even better than hard inorganic substrates, which we attribute to partial graphitization and covalent coupling between PDA subunits during annealing. Moreover, laser annealing provides these benefits while preserving other attractive properties of PDA, as demonstrated by the superior biofouling resistance of antifouling polymer-grafted LAPDA compared to PDA modified with the same polymer. Our work suggests that laser annealing may allow the use of PDA in mechanically demanding applications previously considered inaccessible, without sacrificing the functional versatility that is so characteristic of PDA.


Assuntos
Indóis/química , Indóis/efeitos da radiação , Lasers , Polímeros/química , Polímeros/efeitos da radiação , Incrustação Biológica , Materiais Revestidos Biocompatíveis/química , Teste de Materiais , Propriedades de Superfície
10.
Nat Commun ; 11(1): 4511, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908128

RESUMO

Serial femtosecond crystallography (SFX) with X-ray free electron lasers (XFELs) allows structure determination of membrane proteins and time-resolved crystallography. Common liquid sample delivery continuously jets the protein crystal suspension into the path of the XFEL, wasting a vast amount of sample due to the pulsed nature of all current XFEL sources. The European XFEL (EuXFEL) delivers femtosecond (fs) X-ray pulses in trains spaced 100 ms apart whereas pulses within trains are currently separated by 889 ns. Therefore, continuous sample delivery via fast jets wastes >99% of sample. Here, we introduce a microfluidic device delivering crystal laden droplets segmented with an immiscible oil reducing sample waste and demonstrate droplet injection at the EuXFEL compatible with high pressure liquid delivery of an SFX experiment. While achieving ~60% reduction in sample waste, we determine the structure of the enzyme 3-deoxy-D-manno-octulosonate-8-phosphate synthase from microcrystals delivered in droplets revealing distinct structural features not previously reported.


Assuntos
Cristalografia/instrumentação , Elétrons , Dispositivos Lab-On-A-Chip , Lasers , Aldeído Liases/ultraestrutura , Proteínas de Escherichia coli/ultraestrutura , Hidrodinâmica
11.
Nat Commun ; 11(1): 4536, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913189

RESUMO

Natural musculoskeletal systems have been widely recognized as an advanced robotic model for designing robust yet flexible microbots. However, the development of artificial musculoskeletal systems at micro-nanoscale currently remains a big challenge, since it requires precise assembly of two or more materials of distinct properties into complex 3D micro/nanostructures. In this study, we report femtosecond laser programmed artificial musculoskeletal systems for prototyping 3D microbots, using relatively stiff SU-8 as the skeleton and pH-responsive protein (bovine serum albumin, BSA) as the smart muscle. To realize the programmable integration of the two materials into a 3D configuration, a successive on-chip two-photon polymerization (TPP) strategy that enables structuring two photosensitive materials sequentially within a predesigned configuration was proposed. As a proof-of-concept, we demonstrate a pH-responsive spider microbot and a 3D smart micro-gripper that enables controllable grabbing and releasing. Our strategy provides a universal protocol for directly printing 3D microbots composed of multiple materials.


Assuntos
Biomimética/métodos , Compostos de Epóxi/efeitos da radiação , Fenômenos Fisiológicos Musculoesqueléticos , Polímeros/efeitos da radiação , Robótica/métodos , Soroalbumina Bovina/efeitos da radiação , Biomimética/instrumentação , Compostos de Epóxi/química , Hidrogéis/química , Hidrogéis/efeitos da radiação , Concentração de Íons de Hidrogênio , Lasers , Polimerização/efeitos da radiação , Polímeros/química , Impressão Tridimensional , Robótica/instrumentação , Soroalbumina Bovina/química
12.
Georgian Med News ; (303): 7-12, 2020 Jun.
Artigo em Russo | MEDLINE | ID: mdl-32841173

RESUMO

Aim - to improve the results of treatment of pressure sores using low-energy laser technology. The authors performed a comparative analysis of the effectiveness of the use of low-energy laser irradiation in the complex treatment of pressure ulcers of 2-3 degrees in 35 patients with severe brain damage for the period from 2017-2019. The contact laser was used with the following parameters: wave length - 904 nm, frequency - 5000 Hz, irradiation mode - pulsed, power - 13.5mWt/cm2, exposure - on average 2 minutes per zone. The results were compared with those in 41 people treated according to the traditional methodology. The demographic criteria, localization and length of the process did not have significant intergroup differences. The use of low-energy laser technology in combination with other conservative methods made it possible to accelerate the healing of pressure sores by 1.3-1.4 times, and to reduce the degree of microbial contamination of the focus in earlier periods (p<0.05). At the same time, both the duration of the inpatient rehabilitation phase and the overall treatment costs are reduced. An integrated approach using low-energy laser technology as an additional physical factor can significantly improve the results of the treatment of pressure sores in people with severe brain damage.


Assuntos
Lesão por Pressão , Encéfalo , Humanos , Lasers , Luz , Cicatrização
13.
Waste Manag ; 117: 48-57, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32805601

RESUMO

We present, rapid and efficient identification of ten different types of post-consumer plastics obtained from a local recycling unit by deploying a low cost, compact CCD spectrometer in laser-induced breakdown spectroscopy (LIBS) technique. For this investigation, spectral emissions were collected by an Echelle spectrograph equipped with an intensified charge-coupled device (ES-ICCD) as well as a non-gated Czerny Turner CCD spectrometer (NCT-CCD). The performance is evaluated by interrogating the samples in a single-shot as well as accumulation mode (ten consecutive laser shots). The results from principal component analysis (PCA) have shown excellent discrimination. Further, the artificial neural network (ANN) analysis has demonstrated that individual identification accuracies/rates up to ~99 % can be achieved. The data acquired with ES-ICCD in the accumulation of ten shots have shown average identification accuracies ~97 %. Nevertheless, similar performance is achieved with the NCT-CCD spectrometer even in a single shot acquisition which reduces the overall analysis time by a factor of ~15 times compared to the ES-ICCD. Furthermore, the detector/collection system size, weight, and cost also can be reduced by ~10 times by employing a NCT-CCD spectrometer. The results have the potential in realizing a compact and low-cost LIBS system for the rapid identification of plastics with higher accuracies for the real-time application.


Assuntos
Lasers , Plásticos , Análise de Componente Principal , Reciclagem , Análise Espectral
14.
Int J Nanomedicine ; 15: 5517-5526, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801703

RESUMO

Introduction: Hypertension is a major health problem worldwide and is typically treated using oral drugs. However, the frequency of oral administration may result in poor patient compliance, and reduced bioavailability owing to the first-pass effect can also prove problematic. Methods: In this study, we developed a new transdermal-drug-delivery system (TDDS) for the treatment of hypertension using atenolol (ATE) based on poly(acrylic acid) (PAA)-decorated three-dimensional (3D) flower-like MoS2 nanoparticles (PAA-MoS2 NPs) that respond to NIR laser irradiation. The PAA-modified MoS2 NPs were synthesized and characterized using attenuated total reflection Fourier-transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and the sedimentation equilibrium method. The drug-loading efficiency and photothermal conversion effect were also explored. Results: The results showed that the colloidally stable PAA-MoS2 NPs exhibited a high drug-loading capacity of 54.99% and high photothermal conversion ability. Further, the capacity of the PAA-MoS2 NPs for controlled release was explored using in vitro drug-release and skin-penetration studies. The drug-release percentage was 44.72 ± 1.04%, and skin penetration was enhanced by a factor of 1.85 in the laser-stimulated group. Sustained and controlled release by the developed TDDS were observed with laser stimulation. Moreover, in vivo erythema index analysis verified that the PAA-MoS2 NPs did not cause skin irritation. Discussion: Our findings demonstrate that PAA-MoS2 NPs can be used as a new carrier for transdermal drug delivery for the first time.


Assuntos
Anti-Hipertensivos/administração & dosagem , Atenolol/administração & dosagem , Dissulfetos/química , Sistemas de Liberação de Medicamentos/métodos , Molibdênio/química , Nanopartículas/administração & dosagem , Resinas Acrílicas/química , Administração Cutânea , Animais , Anti-Hipertensivos/farmacocinética , Atenolol/efeitos adversos , Atenolol/farmacocinética , Sistemas de Liberação de Medicamentos/efeitos adversos , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Eritema/induzido quimicamente , Humanos , Lasers , Masculino , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Coelhos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
Proc Natl Acad Sci U S A ; 117(33): 20265-20273, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32747555

RESUMO

Huntington disease (HD) is an ideal model for investigating selective neurodegeneration, as expanded polyQ repeats in the ubiquitously expressed huntingtin (HTT) cause the preferential neurodegeneration in the striatum of the HD patient brains. Here we report that adeno-associated virus (AAV) transduction-mediated depletion of Hap1, the first identified huntingtin-associated protein, in adult HD knock-in (KI) mouse brains leads to selective neuronal loss in the striatum. Further, Hap1 depletion-mediated neuronal loss via AAV transduction requires the presence of mutant HTT. Rhes, a GTPase that is enriched in the striatum and sumoylates mutant HTT to mediate neurotoxicity, binds more N-terminal HTT when Hap1 is deficient. Consistently, more soluble and sumoylated N-terminal HTT is presented in HD KI mouse striatum when HAP1 is absent. Our findings suggest that both Rhes and Hap1 as well as cellular stress contribute to the preferential neurodegeneration in HD, highlighting the involvement of multiple factors in selective neurodegeneration.


Assuntos
Corpo Estriado/patologia , Doença de Huntington/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurônios/fisiologia , Optogenética , Animais , Corpo Estriado/metabolismo , Dependovirus , Regulação da Expressão Gênica , Doença de Huntington/genética , Lasers , Luz , Camundongos , Rede Nervosa , Proteínas do Tecido Nervoso/genética
16.
ACS Nano ; 14(9): 12045-12053, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32790338

RESUMO

Wearing face masks has been widely recommended to contain respiratory virus diseases, yet the improper use of masks poses a threat of jeopardizing the protection effect. We here identified the bacteria viability on common face masks and found that the majority of bacteria (90%) remain alive after 8 h. Using laser-induced graphene (LIG), the inhibition rate improves to ∼81%. Combined with the photothermal effect, 99.998% bacterial killing efficiency could be attained within 10 min. For aerosolized bacteria, LIG also showed superior antibacterial capacity. The LIG can be converted from a diversity of carbon precursors including biomaterials, which eases the supply stress and environmental pressure amid an outbreak. In addition, self-reporting of mask conditions is feasible using the moisture-induced electricity from gradient graphene. Our results improve the safe use of masks and benefit the environment.


Assuntos
Antibacterianos/farmacologia , Grafite/farmacologia , Lasers , Luz , Viabilidade Microbiana , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/fisiologia
17.
BMC Bioinformatics ; 21(1): 336, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727348

RESUMO

BACKGROUND: Machine learning models for repeated measurements are limited. Using topological data analysis (TDA), we present a classifier for repeated measurements which samples from the data space and builds a network graph based on the data topology. A machine learning model with cross-validation is then applied for classification. When test this on three case studies, accuracy exceeds an alternative support vector machine (SVM) voting model in most situations tested, with additional benefits such as reporting data subsets with high purity along with feature values. RESULTS: For 100 examples of 3 different tree species, the model reached 80% classification accuracy after 30 datapoints, which was improved to 90% after increased sampling to 400 datapoints. The alternative SVM classifier achieved a maximum accuracy of 68.7%. Using data from 100 examples from each class of 6 different random point processes, the classifier achieved 96.8% accuracy, vastly outperforming the SVM. Using two outcomes in neuron spiking data, the TDA classifier was similarly accurate to the SVM in one case (both converged to 97.8% accuracy), but was outperformed in the other (relative accuracies 79.8% and 92.2%, respectively). CONCLUSIONS: This algorithm and software can be beneficial for repeated measurement data common in biological sciences, as both an accurate classifier and a feature selection tool.


Assuntos
Algoritmos , Análise de Dados , Animais , Simulação por Computador , Humanos , Lasers , Aprendizado de Máquina , Ratos , Máquina de Vetores de Suporte , Árvores/anatomia & histologia
18.
BMC Bioinformatics ; 21(1): 335, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32727350

RESUMO

BACKGROUND: The efficient and robust statistical analysis of the shape of plant organs of different cultivars is an important investigation issue in plant breeding and enables a robust cultivar description within the breeding progress. Laserscanning is a highly accurate and high resolution technique to acquire the 3D shape of plant surfaces. The computation of a shape based principal component analysis (PCA) built on concepts from continuum mechanics has proven to be an effective tool for a qualitative and quantitative shape examination. RESULTS: The shape based PCA was used for a statistical analysis of 140 sugar beet roots of different cultivars. The calculation of the mean sugar beet root shape and the description of the main variations was possible. Furthermore, unknown and individual tap roots could be attributed to their cultivar by means of a robust classification tool based on the PCA results. CONCLUSION: The method demonstrates that it is possible to identify principal modes of root shape variations automatically and to quantify associated variances out of laserscanned 3D sugar beet tap root models. The introduced approach is not limited to the 3D shape description by laser scanning. A transfer to 3D MRI or radar data is also conceivable.


Assuntos
Beta vulgaris/anatomia & histologia , Lasers , Raízes de Plantas/anatomia & histologia , Estatística como Assunto , Análise de Componente Principal
20.
Nature ; 583(7814): 35-36, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32612219
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