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1.
Food Chem ; 366: 130553, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284194

RESUMO

A method for real-time monitoring of lipid digestion based on photonic crystals formed from silica was developed. As an effective "net", the highly ordered silica colloidal crystal (SCC) film provides structural support for lipid payload. This method based on optical interferometric film kinetics was used to record the whole kinetics progress of olive oil hydrolysis by lipase in real time and calculate the kinetic Michaelis constant. The kinetic parameters were compared with the results determined by the titration method. The effects of bile salt content on lipase and olive oil layer were studied. This method provides a potential evaluation system for real-time digestion and degradation of edible oil in the food field. It also provides a basis for further real-time evaluation of lipid bioavailability in food systems by real-time recording the release and degradation of lipids in the food nano-matrix.


Assuntos
Lipídeos , Lipólise , Digestão , Interferometria , Lipase/metabolismo
2.
Talanta ; 237: 122958, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736683

RESUMO

Immunoglobulin G (IgG) is a significant ingredient of immunological activity in milk and colostrum, the activity and content of which is easily disturbed by potentially conditional variant during sterilization. Therefore, developing robust methods for the detection of IgG levels in milk is especially important. Herein, protein A from the Staphylococcus aureus functionalized silica colloidal crystalline film (SCC@SPA) sensing unit combined with ordered porous layer interferometry (OPLI) for IgG detection in untreated bovine milk was developed. Calibration curves in milk and buffer were set up by the variations of the optical thickness (OT) of the sensing unit after the IgG association and dissociation phases. The influence of temperature on the level of IgG was evaluated. Furthermore, the identification of IgG levels with pasteurized milk and ultrahigh temperature (UHT) sterilized milk from the market randomly was successfully carried out without any sample pretreatment. More importantly, compared with other methods, this novel method has the advantages of convenient operation, low cost, and suitability for point-of-care (POC) testing.


Assuntos
Colostro , Leite , Animais , Bovinos , Feminino , Imunoglobulina G , Interferometria , Porosidade , Gravidez
3.
J Synchrotron Radiat ; 28(Pt 6): 1966-1977, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34738952

RESUMO

The SAGA Light Source provides X-ray imaging resources based on high-intensity synchrotron radiation (SR) emitted from the superconducting wiggler at beamline 07 (BL07). By combining quasi-monochromatic SR obtained by the newly installed water-cooled metal filter and monochromatic SR selected by a Ge double-crystal monochromator (DCM) with high-resolution lens-coupled X-ray imagers, fast and low-dose micro-computed tomography (CT), fast phase-contrast CT using grating-based X-ray interferometry, and 2D micro-X-ray absorption fine structure analysis can be performed. In addition, by combining monochromatic SR obtained by a Si DCM with large-area fiber-coupled X-ray imagers, high-sensitivity phase-contrast CT using crystal-based X-ray interferometry can be performed. Low-temperature CT can be performed using the newly installed cryogenic system, and time-resolved analysis of the crystallinity of semiconductor devices in operation can be performed using a time-resolved topography system. The details of each instrument and imaging method, together with exemplary measurements, are presented.


Assuntos
Interferometria , Síncrotrons , Microtomografia por Raio-X , Raios X
4.
Sheng Wu Gong Cheng Xue Bao ; 37(9): 3300-3309, 2021 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-34622637

RESUMO

In Gram-negative bacteria, lipopolysaccharide transport (Lpt) protein LptA and LptC form a complex to transport LPS from the inner membrane (IM) to the outer membrane (OM). Blocking the interaction between LptA and LptC will lead to the defect of OM and cell death. Therefore, Lpt protein interaction could be used as a target to screen new drugs for killing Gram-negative bacteria. Here we used biolayer interferometry (BLI) assay to detect the interaction between LptA and LptC, with the aim to develop a method for screening the LptA/LptC interaction blockers in vitro. Firstly, LptC and LptA with or without signal peptide (LptAfull or LptAno signal) were expressed in E. coli BL21(DE3). The purified proteins were then labeled with biotin and the super streptavidin (SSA) biosensor was blocked with diluent. The biotin labeled protein sample was mixed with the sensor, and then the binding of the protein with a series of diluted non biotinylated protein was detected. At the same time, non-biotinylated protein was used as a control. The binding of biotinylated protein to a small molecule IMB-881 and the blocking of interaction were also detected by the same method. In the blank control, the biosensor without biotinylated protein was used to detect the serially diluted samples. The signal response constant was calculated by using steady analysis. The results showed that biotinylated LptC had a good binding activity with LptAfull and LptAno signal with KD value 2.9e⁻7±7.9e⁻8 and 6.0e⁻7±2.8e⁻8, respectively; biotinylated LptAno signal had a good binding activity with LptC, with a KD value of 9.6e⁻7±7.2e⁻8. All binding curves showed obvious fast binding and fast dissociation morphology. The small molecule compound IMB-881 can bind to LptA to block the interaction between LptA and LptC, but has no binding activity with LptC. In summary, we developed a method for detecting the LptA/LptC interaction based on the BLI technology, and confirmed that this method can be used to evaluate the blocking activity of small molecule blockers, providing a new approach for the screening of LptA/LptC interaction blockers.


Assuntos
Proteínas de Escherichia coli , Escherichia coli , Proteínas de Transporte , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Interferometria , Proteínas de Membrana/metabolismo
5.
Sensors (Basel) ; 21(19)2021 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-34640918

RESUMO

We report a novel Mach-Zehnder interferometer (MZI) sensor that utilizes a weak one-dimensional field confinement silica waveguide (WCSW). The WCSW has a large horizontal and vertical aspect ratio and low refractive index difference, which features easy preparation and a large evanescent field for achieving high waveguide sensitivity. We experimentally achieved WCSW ultrahigh waveguide sensitivity of 0.94, MZI sensitivity of 44,364 π/RIU and a low limit of detection (LOD) of 6.1 × 10-7 RIU.


Assuntos
Técnicas Biossensoriais , Interferometria , Limite de Detecção , Refratometria , Dióxido de Silício
6.
Sensors (Basel) ; 21(20)2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34696012

RESUMO

Landslides are one of the most destructive natural hazards worldwide, affecting greatly built-up areas and critical infrastructure, causing loss of human lives, injuries, destruction of properties, and disturbance in everyday commute. Traditionally, landslides are monitored through time consuming and costly in situ geotechnical investigations and a wide range of conventional means, such as inclinometers and boreholes. Earth Observation and the exploitation of the freely available Copernicus datasets, and especially Sentinel-1 Synthetic Aperture Radar (SAR) images, can assist in the systematic monitoring of landslides, irrespective of weather conditions and time of day, overcoming the restrictions arising from in situ measurements. In the present study, a comprehensive statistical analysis of coherence obtained through processing of a time-series of Sentinel-1 SAR imagery was carried out to investigate and detect early indications of a landslide that took place in Cyprus on 15 February 2019. The application of the proposed methodology led to the detection of a sudden coherence loss prior to the landslide occurrence that can be used as input to Early Warning Systems, giving valuable on-time information about an upcoming landslide to emergency response authorities and the public, saving numerous lives. The statistical significance of the results was tested using Analysis of Variance (ANOVA) tests and two-tailed t-tests.


Assuntos
Deslizamentos de Terra , Humanos , Interferometria , Radar , Projetos de Pesquisa , Tempo (Meteorologia)
7.
Nat Commun ; 12(1): 5545, 2021 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-34545070

RESUMO

The RAD51 recombinase assembles as helical nucleoprotein filaments on single-stranded DNA (ssDNA) and mediates invasion and strand exchange with homologous duplex DNA (dsDNA) during homologous recombination (HR), as well as protection and restart of stalled replication forks. Strand invasion by RAD51-ssDNA complexes depends on ATP binding. However, RAD51 can bind ssDNA in non-productive ADP-bound or nucleotide-free states, and ATP-RAD51-ssDNA complexes hydrolyse ATP over time. Here, we define unappreciated mechanisms by which the RAD51 paralog complex RFS-1/RIP-1 limits the accumulation of RAD-51-ssDNA complexes with unfavorable nucleotide content. We find RAD51 paralogs promote the turnover of ADP-bound RAD-51 from ssDNA, in striking contrast to their ability to stabilize productive ATP-bound RAD-51 nucleoprotein filaments. In addition, RFS-1/RIP-1 inhibits binding of nucleotide-free RAD-51 to ssDNA. We propose that 'nucleotide proofreading' activities of RAD51 paralogs co-operate to ensure the enrichment of active, ATP-bound RAD-51 filaments on ssDNA to promote HR.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Nucleotídeos/metabolismo , Rad51 Recombinase/química , Rad51 Recombinase/metabolismo , Homologia de Sequência de Aminoácidos , Difosfato de Adenosina/farmacologia , Trifosfato de Adenosina/farmacologia , Animais , DNA de Cadeia Simples/metabolismo , Fluorescência , Interferometria , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Especificidade da Espécie
8.
Sensors (Basel) ; 21(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34502660

RESUMO

Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) techniques are gaining momentum in the assessment and health monitoring of infrastructure assets. Amongst others, the Persistent Scatterers Interferometry (PSI) technique has proven to be viable for the long-term evaluation of ground scatterers. However, its effectiveness as a routine tool for certain critical application areas, such as the assessment of millimetre-scale differential displacements in airport runways, is still debated. This research aims to demonstrate the viability of using medium-resolution Copernicus ESA Sentinel-1A (C-Band) SAR products and their contribution to improve current maintenance strategies in case of localised foundation settlements in airport runways. To this purpose, "Runway n.3" of the "Leonardo Da Vinci International Airport" in Fiumicino, Rome, Italy was investigated as an explanatory case study, in view of historical geotechnical settlements affecting the runway area. In this context, a geostatistical study is developed for the exploratory spatial data analysis and the interpolation of the Sentinel-1A SAR data. The geostatistical analysis provided ample information on the spatial continuity of the Sentinel 1 data in comparison with the high-resolution COSMO-SkyMed data and the ground-based topographic levelling data. Furthermore, a comparison between the PSI outcomes from the Sentinel-1A SAR data-interpolated through Ordinary Kriging-and the ground-truth topographic levelling data demonstrated the high accuracy of the Sentinel 1 data. This is proven by the high values of the correlation coefficient (r = 0.94), the multiple R-squared coefficient (R2 = 0.88) and the Slope value (0.96). The results of this study clearly support the effectiveness of using Sentinel-1A SAR data as a continuous and long-term routine monitoring tool for millimetre-scale displacements in airport runways, paving the way for the development of more efficient and sustainable maintenance strategies for inclusion in next generation Airport Pavement Management Systems (APMSs).


Assuntos
Aeroportos , Radar , Interferometria , Itália
9.
Sensors (Basel) ; 21(17)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34502760

RESUMO

A 3-aminopropyl-triethoxysilane (APES) fiber-optic sensor based on a Mach-Zehnder interferometer (MZI) was demonstrated. The MZI was constructed with a core-offset fusion single mode fiber (SMF) structure with a length of 3.0 cm. As APES gradually attaches to the MZI, the external environment of the MZI changes, which in turn causes change in the MZI's interference. That is the reason why we can obtain the relationships between the APES amount and resonance dip wavelength by measuring the transmission variations of the resonant dip wavelength of the MZI. The optimized amount of 1% APES for 3.0 cm MZI biosensors was 3 mL, whereas the optimized amount of 2% APES was 1.5 mL.


Assuntos
Técnicas Biossensoriais , Hominidae , Animais , Tecnologia de Fibra Óptica , Interferometria , Fibras Ópticas
10.
Med Phys ; 48(10): 6508-6523, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34554568

RESUMO

PURPOSE: Advances in X-ray phase-contrast imaging can obtain excellent soft-tissue contrast of phase-shift, attenuation, and small-angle scatter. Here, we present fringe patterns for different design parameters of X-ray bi-prism interferometry imaging systems. Our aim is to develop bi-prism interferometry imaging systems with excellent polychromatic performance that produce high-contrast fringes with spatially incoherent X-ray illumination. We also introduce a novel X-ray tube design that uses temporal multiplexing to provide simultaneous virtual "electronic phase stepping" that replace "mechanical phase stepping" popular with grating-based interferometry setups. METHODS: In our investigation, we develop expressions for the irradiance distribution pattern of a bi-prism interferometer composed of multiple point sources and multiple bi-prisms. These expressions are used to plot fringe patterns for X-ray design parameters, including size of point source, number of point sources, and point source separation, and bi-prism design parameters including material, angle, number of bi-prisms, period, and bi-prism array to X-ray source and detector distances. RESULTS: Results show that the fringe patterns for a bi-prism interferometry system are not longitudinally periodic as with grating interferometers that produce a Talbot-Lau carpet. It is also shown that at 59 keV X-rays the bi-prism material should be something comparable to nickel to obtain reasonable fringe visibility. CONCLUSION: The irradiance distribution pattern demonstrates that bi-prism interferometry may provide comparable or improved fringe visibility to that of gratings. Special care is given to present our findings within the context of previous advancements. A single-shot image acquisition approach using a temporal multiplexed, high-power X-ray source provides virtual electronic phase stepping without focal spot sweeping. This provides multiple images, each at the same exposure and the same projection view, from different fringe locations that allow one to derive the attenuation, phase, and dark-field images of the sample without mechanical phase stepping of a grating.


Assuntos
Interferometria , Radiografia , Raios X
11.
J Biol Chem ; 297(4): 101151, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34478710

RESUMO

The seasonal nature of outbreaks of respiratory viral infections with increased transmission during low temperatures has been well established. Accordingly, temperature has been suggested to play a role on the viability and transmissibility of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The receptor-binding domain (RBD) of the Spike glycoprotein is known to bind to its host receptor angiotensin-converting enzyme 2 (ACE2) to initiate viral fusion. Using biochemical, biophysical, and functional assays to dissect the effect of temperature on the receptor-Spike interaction, we observed a significant and stepwise increase in RBD-ACE2 affinity at low temperatures, resulting in slower dissociation kinetics. This translated into enhanced interaction of the full Spike glycoprotein with the ACE2 receptor and higher viral attachment at low temperatures. Interestingly, the RBD N501Y mutation, present in emerging variants of concern (VOCs) that are fueling the pandemic worldwide (including the B.1.1.7 (α) lineage), bypassed this requirement. This data suggests that the acquisition of N501Y reflects an adaptation to warmer climates, a hypothesis that remains to be tested.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Enzima de Conversão de Angiotensina 2/química , COVID-19/patologia , COVID-19/virologia , Calorimetria , Humanos , Interferometria , Polimorfismo de Nucleotídeo Único , Ligação Proteica , Estrutura Quaternária de Proteína , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/química , Temperatura , Termodinâmica
12.
J Biol Chem ; 297(4): 101175, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34499924

RESUMO

The spike protein is the main protein component of the SARS-CoV-2 virion surface. The spike receptor-binding motif mediates recognition of the human angiotensin-converting enzyme 2 receptor, a critical step in infection, and is the preferential target for spike-neutralizing antibodies. Posttranslational modifications of the spike receptor-binding motif have been shown to modulate viral infectivity and host immune response, but these modifications are still being explored. Here we studied asparagine deamidation of the spike protein, a spontaneous event that leads to the appearance of aspartic and isoaspartic residues, which affect both the protein backbone and its charge. We used computational prediction and biochemical experiments to identify five deamidation hotspots in the SARS-CoV-2 spike protein. Asparagine residues 481 and 501 in the receptor-binding motif deamidate with a half-life of 16.5 and 123 days at 37 °C, respectively. Deamidation is significantly slowed at 4 °C, indicating a strong dependence of spike protein molecular aging on environmental conditions. Deamidation of the spike receptor-binding motif decreases the equilibrium constant for binding to the human angiotensin-converting enzyme 2 receptor more than 3.5-fold, yet its high conservation pattern suggests some positive effect on viral fitness. We propose a model for deamidation of the full SARS-CoV-2 virion illustrating how deamidation of the spike receptor-binding motif could lead to the accumulation on the virion surface of a nonnegligible chemically diverse spike population in a timescale of days. Our findings provide a potential mechanism for molecular aging of the spike protein with significant consequences for understanding virus infectivity and vaccine development.


Assuntos
SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Motivos de Aminoácidos , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/patologia , COVID-19/virologia , Humanos , Concentração de Íons de Hidrogênio , Interferometria , Cinética , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , SARS-CoV-2/isolamento & purificação , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus/química
13.
Biosensors (Basel) ; 11(8)2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34436068

RESUMO

In the present paper, we describe a potassium sensor based on DNA-aptamer functionalized hydrogel, that is capable of continuous label-free potassium ion (K+) monitoring with potential for in situ application. A hydrogel attached to the end of an optical fiber is designed with di-oligonucleotides grafted to the polymer network that may serve as network junctions in addition to the covalent crosslinks. Specific affinity toward K+ is based on exploiting a particular aptamer that exhibits conformational transition from single-stranded DNA to G-quadruplex formed by the di-oligonucleotide in the presence of K+. Integration of this aptamer into the hydrogel transforms the K+ specific conformational transition to a K+ concentration dependent deswelling of the hydrogel. High-resolution interferometry monitors changes in extent of swelling at 1 Hz and 2 nm resolution for the hydrogel matrix of 50 µm. The developed hydrogel-based biosensor displayed high selectivity for K+ ions in the concentration range up to 10 mM, in the presence of physiological concentrations of Na+. Additionally, the concentration dependent and selective K+ detection demonstrated in the artificial blood buffer environment, both at room and physiological temperatures, suggests substantial potential for practical applications such as monitoring of potassium ion concentration in blood levels in intensive care medicine.


Assuntos
Aptâmeros de Nucleotídeos , Tecnologia de Fibra Óptica , Hidrogéis , Técnicas Biossensoriais , Quadruplex G , Humanos , Interferometria , Íons , Fibras Ópticas , Potássio , Temperatura
14.
Biosensors (Basel) ; 11(7)2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34356688

RESUMO

We report an effective surface immobilization protocol for capture of Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), a receptor whose elevated concentration in cerebrospinal fluid has recently been associated with Alzheimer's disease (AD). We employ the proposed surface functionalization scheme to design, fabricate, and assess a biochemical sensing platform based on plasmonic interferometry that is able to detect physiological concentrations of TREM2 in solution. These findings open up opportunities for label-free biosensing of TREM2 in its soluble form in various bodily fluids as an early indicator of the onset of clinical dementia in AD. We also show that plasmonic interferometry can be a powerful tool to monitor and optimize surface immobilization schemes, which could be applied to develop other relevant antibody tests.


Assuntos
Interferometria , Glicoproteínas de Membrana , Receptores Imunológicos , Doença de Alzheimer/diagnóstico , Encéfalo , Humanos
15.
Pharmacol Res ; 172: 105820, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34403732

RESUMO

Coronavirus Disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which enter the host cells through the interaction between its receptor binding domain (RBD) of spike glycoprotein with angiotensin-converting enzyme 2 (ACE2) receptor on the plasma membrane of host cell. Neutralizing antibodies and peptide binders of RBD can block viral infection, however, the concern of accessibility and affordability of viral infection inhibitors has been raised. Here, we report the identification of natural compounds as potential SARS-CoV-2 entry inhibitors using the molecular docking-based virtual screening coupled with bilayer interferometry (BLI). From a library of 1871 natural compounds, epigallocatechin gallate (EGCG), 20(R)-ginsenoside Rg3 (RRg3), 20(S)-ginsenoside Rg3 (SRg3), isobavachalcone (Ibvc), isochlorogenic A (IscA) and bakuchiol (Bkc) effectively inhibited pseudovirus entry at concentrations up to 100 µM. Among these compounds, four compounds, EGCG, Ibvc, salvianolic acid A (SalA), and isoliensinine (Isl), were effective in inhibiting SARS-CoV-2-induced cytopathic effect and plaque formation in Vero E6 cells. The EGCG was further validated with no observable animal toxicity and certain antiviral effect against SARS-CoV-2 pseudovirus mutants (D614G, N501Y, N439K & Y453F). Interestingly, EGCG, Bkc and Ibvc bind to ACE2 receptor in BLI assay, suggesting a dual binding to RBD and ACE2. Current findings shed some insight into identifications and validations of SARS-CoV-2 entry inhibitors from natural compounds.


Assuntos
Enzima de Conversão de Angiotensina 2/antagonistas & inibidores , Antivirais/química , Produtos Biológicos/química , COVID-19/tratamento farmacológico , Inibidores Enzimáticos/química , SARS-CoV-2/enzimologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Animais , Antivirais/farmacologia , Ligação Competitiva , Produtos Biológicos/farmacologia , Catequina/análogos & derivados , Catequina/farmacologia , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Chalconas/farmacologia , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/farmacologia , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/farmacologia , Ginsenosídeos/farmacologia , Humanos , Interferometria , Camundongos Endogâmicos C57BL , Simulação de Dinâmica Molecular , Fenóis/farmacologia , Ligação Proteica
16.
Transl Vis Sci Technol ; 10(9): 1, 2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34338722

RESUMO

Purpose: This study aimed to determine the intra- and interobserver repeatability of the new LacryDiag Ocular Surface Analyzer and compare it to a similar all-in-one device, the OCULUS Keratograph 5M. Methods: Thirty healthy subjects aged 18 years and above were recruited for this study. All patients were free of any existing ocular pathology. The LacryDiag Ocular Surface Analyzer was used to evaluate tear meniscus height, interferometry, noninvasive tear break-up time (NIBUT), and meibography. The same or analogous exams were performed using the OCULUS Keratograph 5M. Test equivalation was used to compare data from corresponding examinations. Paired t-tests and coefficient of variation were used to determine inter- and intraobserver repeatability. Bland-Altman analysis was used to determine level of agreement between devices. Results: There were no differences in mean values for tear meniscus height, NIBUT, or tear film interferometry between observers for either device. Significant differences were found between observers for meibography when using the LacryDiag (P = 0.008 for percent loss calculation and P = 0.004 for grading scale). Intra-observer variability for NIBUT was significantly higher for the Keratograph (P = 0.0003 for observer A and P < 0.0001 for observer B). Conclusions: There was a good correlation but poor agreement between devices for a given observer. This was likely influenced by the use of repeated testing and the non-dry eye cohort. Translational Relevance: Both the repeatability of the testing device and the use of multiple outcome measures are essential for the diagnosis and monitoring of patients with dry eye disease (DED).


Assuntos
Síndromes do Olho Seco , Glândulas Tarsais , Síndromes do Olho Seco/diagnóstico , Humanos , Interferometria , Variações Dependentes do Observador , Lágrimas
17.
Sensors (Basel) ; 21(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34450913

RESUMO

In this paper, we propose a highly sensitive temperature sensor based on two cascaded Mach-Zehnder interferometers (MZIs) that work using the Vernier effect. The all-fiber MZIs were assembled by splicing a segment of capillary hollow-core fiber (CHCF) between two sections of multimode fibers (MMFs). This cascaded configuration exhibits a temperature sensitivity of 1.964 nm/°C in a range from 10 to 70 °C, which is ~67.03 times higher than the sensitivity of the single MZI. Moreover, this device exhibits a high-temperature resolution of 0.0153 °C. A numerical analysis was carried out to estimate the devices' temperature sensitivity and calculate the magnification of the sensitivity produced by the Vernier effect. The numerical results have an excellent agreement with the experimental results and provide a better insight into the working principle of the MZI devices. The sensor's performance, small size, and easy fabrication make us believe that it is an attractive candidate for temperature measurement in biological applications.


Assuntos
Interferometria , Refratometria , Temperatura Alta , Temperatura
18.
Med Phys ; 48(10): 6293-6311, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34407202

RESUMO

PURPOSE: In this work, we present tomographic simulations of a new hardware concept for X-ray phase-contrast interferometry wherein the phase gratings are replaced with an array of Fresnel biprisms, and Moiré fringe analysis is used instead of "phase stepping" popular with grating-based setups. METHODS: Projections of a phantom consisting of four layers of parallel carbon microfibers is simulated using wave optics representation of X-ray electromagnetic waves. Simulated projections of a phantom with preferential scatter perpendicular to the direction of the fibers are performed to analyze the extraction of small-angle scatter from dark-field projections for the following: (1) biprism interferometry using Moiré fringe analysis; (2) grating interferometry using phase stepping with eight grating steps; and (3) grating interferometry using Moiré fringe analysis. Dark-field projections are modeled as projections of voxel intensities represented by a fixed finite vector basis set of scattering directions. An iterative MLEM algorithm is used to reconstruct, from simulated projection data, the coefficients of a fixed set of seven basis vectors at each voxel representing the small-angle scatter distribution. RESULTS: Results of reconstructed vector coefficients are shown comparing the three simulated imaging configurations. The single-exposure Moiré fringe analysis shows not only an increase in noise because of one-eighth the number of projection samples but also is obtained with less dose and faster acquisition times. Furthermore, replacing grating interferometry with biprism interferometry provides better contrast-to-noise. CONCLUSION: The simulations demonstrate the feasibility of the reconstruction of dark-field data acquired with a biprism interferometry system. With the potential of higher fringe visibility, biprism interferometry with Moiré fringe analysis might provide equal or better image quality to that of phase stepping methods with less imaging time and lower dose.


Assuntos
Interferometria , Tomografia Computadorizada por Raios X , Simulação por Computador , Radiografia , Raios X
19.
Sci Rep ; 11(1): 16113, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34373478

RESUMO

The dark-field signal measures the small-angle scattering strength and provides complementary diagnostic information. This is of particular interest for lung imaging due to the pronounced small-angle scatter from the alveolar microstructure. However, most dark-field imaging techniques are relatively complex, dose-inefficient, and require sophisticated optics and highly coherent X-ray sources. Speckle-based imaging promises to overcome these limitations due to its simple and versatile setup, only requiring the addition of a random phase modulator to conventional X-ray equipment. We investigated quantitatively the influence of sample structure, setup geometry, and source energy on the dark-field signal in speckle-based X-ray imaging with wave-optics simulations for ensembles of micro-spheres. We show that the dark-field signal is accurately predicted via a model originally derived for grating interferometry when using the mean frequency of the speckle pattern power spectral density as the characteristic speckle size. The size directly reflects the correlation length of the diffuser surface and did not change with energy or propagation distance within the near-field. The dark-field signal had a distinct dependence on sample structure and setup geometry but was also affected by beam hardening-induced modifications of the visibility spectrum. This study quantitatively demonstrates the behavior of the dark-field signal in speckle-based X-ray imaging.


Assuntos
Diagnóstico por Imagem/métodos , Pulmão/diagnóstico por imagem , Algoritmos , Estudos de Avaliação como Assunto , Humanos , Interferometria/métodos , Radiografia/métodos , Tomografia Computadorizada por Raios X/métodos , Raios X
20.
Cells ; 10(7)2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209893

RESUMO

Quantitative measurement of single cells can provide in-depth information about cell morphology and metabolism. However, current live-cell imaging techniques have a lack of quantitative detection ability. Herein, we proposed a label-free and quantitative multichannel wide-field interferometric imaging (MWII) technique with femtogram dry mass sensitivity to monitor single-cell metabolism long-term in situ culture. We demonstrated that MWII could reveal the intrinsic status of cells despite fluctuating culture conditions with 3.48 nm optical path difference sensitivity, 0.97 fg dry mass sensitivity and 2.4% average maximum relative change (maximum change/average) in dry mass. Utilizing the MWII system, different intrinsic cell growth characteristics of dry mass between HeLa cells and Human Cervical Epithelial Cells (HCerEpiC) were studied. The dry mass of HeLa cells consistently increased before the M phase, whereas that of HCerEpiC increased and then decreased. The maximum growth rate of HeLa cells was 11.7% higher than that of HCerEpiC. Furthermore, HeLa cells were treated with Gemcitabine to reveal the relationship between single-cell heterogeneity and chemotherapeutic efficacy. The results show that cells with higher nuclear dry mass and nuclear density standard deviations were more likely to survive the chemotherapy. In conclusion, MWII was presented as a technique for single-cell dry mass quantitative measurement, which had significant potential applications for cell growth dynamics research, cell subtype analysis, cell health characterization, medication guidance and adjuvant drug development.


Assuntos
Técnicas de Cultura de Células , Análise de Célula Única , Coloração e Rotulagem , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Células HeLa , Humanos , Imageamento Tridimensional , Interferometria
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