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1.
ACS Nano ; 14(10): 14017-14025, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-32955847

RESUMO

In March of 2020, the World Health Organization declared a pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pandemic led to a shortage of N95-grade filtering facepiece respirators (FFRs), especially surgical-grade N95 FFRs for protection of healthcare professionals against airborne transmission of SARS-CoV-2. We and others have previously reported promising decontamination methods that may be applied to the recycling and reuse of FFRs. In this study we tested disinfection of three viruses, including SARS-CoV-2, dried on a piece of meltblown fabric, the principal component responsible for filtering of fine particles in N95-level FFRs, under a range of temperatures (60-95 °C) at ambient or 100% relative humidity (RH) in conjunction with filtration efficiency testing. We found that heat treatments of 75 °C for 30 min or 85 °C for 20 min at 100% RH resulted in efficient decontamination from the fabric of SARS-CoV-2, human coronavirus NL63 (HCoV-NL63), and another enveloped RNA virus, chikungunya virus vaccine strain 181/25 (CHIKV-181/25), without lowering the meltblown fabric's filtration efficiency.


Assuntos
Desinfecção/métodos , Temperatura Alta , Umidade , Máscaras/virologia , Têxteis/virologia , Betacoronavirus/patogenicidade , Máscaras/normas , Polipropilenos/química , Têxteis/normas
2.
Structure ; 2020 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-32763141

RESUMO

Single-molecule detection and manipulation is a powerful tool for unraveling dynamic biological processes. Unfortunately, success in such experiments is often challenged by tethering the biomolecule(s) of interest to a biocompatible surface. Here, we describe a robust surface passivation method by dense polymer brush grafting, based on optimized polyethylene glycol (PEG) deposition conditions, exactly at the lower critical point of an aqueous biphasic PEG-salt system. The increased biocompatibility achieved, compared with PEG deposition in sub-optimal conditions away from the critical point, allowed us to successfully detect the assembly and function of a large macromolecular machine, a fluorescent-labeled multi-subunit, human RNA Polymerase II Transcription Pre-Initiation Complex, on single, promoter-containing, surface-immobilized DNA molecules. This platform will enable probing the complex biochemistry and dynamics of large, multi-subunit macromolecular assemblies, such as during the initiation of human RNA Pol II transcription, at the single-molecule level.

3.
PLoS One ; 15(7): e0234851, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609741

RESUMO

A lack of N95 Filtering Facepiece Respirators (FFRs) during the COVID-19 crisis has placed healthcare workers at risk. It is important for any N95 reuse strategy to determine the effects that proposed protocols would have on the physical functioning of the mask, as well as the practical aspects of implementation. Here we propose and implement a method of heating N95 respirators with moisture (85°C, 60-85% humidity). We test both mask filtration efficiency and fit to validate this process. Our tests focus on the 3M 1860, 3M 1870, and 3M 8210 Plus N95 models. After five cycles of the heating procedure, all three respirators pass both quantitative fit testing (score of >100) and show no degradation of mask filtration efficiency. We also test the Chen Heng V9501 KN95 and HKYQ N95 finding no degradation of mask filtration efficiency, however even for unheated masks these scored <50 for every fit test. The heating method presented here is scalable from individual masks to over a thousand a day with a single industrial convection oven, making this method practical for local application inside health-care facilities.


Assuntos
Betacoronavirus , Infecções por Coronavirus/epidemiologia , Descontaminação/métodos , Reutilização de Equipamento , Calefação/métodos , Umidade , Máscaras/virologia , Pneumonia Viral/epidemiologia , Dispositivos de Proteção Respiratória/virologia , Infecções por Coronavirus/virologia , Filtração/instrumentação , Humanos , Teste de Materiais/métodos , Exposição Ocupacional/prevenção & controle , Pandemias , Pneumonia Viral/virologia
4.
Nano Lett ; 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: covidwho-459118

RESUMO

The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5-25%, polypropylene spunbond had filtration efficiency 6-10%, and paper-based products had filtration efficiency of 10-20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.

5.
Artigo em Inglês | MEDLINE | ID: mdl-32484683

RESUMO

The COVID-19 pandemic is currently causing a severe disruption and shortage in the global supply chain of necessary personal protective equipment (e.g., N95 respirators). The U.S. CDC has recommended use of household cloth by the general public to make cloth face coverings as a method of source control. We evaluated the filtration properties of natural and synthetic materials using a modified procedure for N95 respirator approval. Common fabrics of cotton, polyester, nylon, and silk had filtration efficiency of 5-25%, polypropylene spunbond had filtration efficiency 6-10%, and paper-based products had filtration efficiency of 10-20%. An advantage of polypropylene spunbond is that it can be simply triboelectrically charged to enhance the filtration efficiency (from 6 to >10%) without any increase in pressure (stable overnight and in humid environments). Using the filtration quality factor, fabric microstructure, and charging ability, we are able to provide an assessment of suggested fabric materials for homemade facial coverings.


Assuntos
Betacoronavirus , Infecções por Coronavirus/prevenção & controle , Máscaras , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Têxteis , Aerossóis , Microbiologia do Ar , Infecções por Coronavirus/transmissão , Eletricidade , Desenho de Equipamento , Filtração , Humanos , Máscaras/provisão & distribução , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia , Tamanho da Partícula , Equipamento de Proteção Individual/provisão & distribução , Pneumonia Viral/transmissão
6.
ACS Nano ; 14(5): 6348-6356, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: covidwho-175663

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic has led to a major shortage of N95 respirators, which are essential for protecting healthcare professionals and the general public who may come into contact with the virus. Thus, it is essential to determine how we can reuse respirators and other personal protective equipment in these urgent times. We investigated multiple commonly used disinfection schemes on media with particle filtration efficiency of 95%. Heating was recently found to inactivate the virus in solution within 5 min at 70 °C and is among the most scalable, user-friendly methods for viral disinfection. We found that heat (≤85 °C) under various humidities (≤100% relative humidity, RH) was the most promising, nondestructive method for the preservation of filtration properties in meltblown fabrics as well as N95-grade respirators. At 85 °C, 30% RH, we were able to perform 50 cycles of heat treatment without significant changes in the filtration efficiency. At low humidity or dry conditions, temperatures up to 100 °C were not found to alter the filtration efficiency significantly within 20 cycles of treatment. Ultraviolet (UV) irradiation was a secondary choice, which was able to withstand 10 cycles of treatment and showed small degradation by 20 cycles. However, UV can potentially impact the material strength and subsequent sealing of respirators. Finally, treatments involving liquids and vapors require caution, as steam, alcohol, and household bleach all may lead to degradation of the filtration efficiency, leaving the user vulnerable to the viral aerosols.


Assuntos
Desinfecção/métodos , Máscaras/normas , Dispositivos de Proteção Respiratória/normas , Desinfecção/normas , Calefação/métodos , Têxteis/normas
7.
ACS Nano ; 14(5): 6348-6356, 2020 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-32368894

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic has led to a major shortage of N95 respirators, which are essential for protecting healthcare professionals and the general public who may come into contact with the virus. Thus, it is essential to determine how we can reuse respirators and other personal protective equipment in these urgent times. We investigated multiple commonly used disinfection schemes on media with particle filtration efficiency of 95%. Heating was recently found to inactivate the virus in solution within 5 min at 70 °C and is among the most scalable, user-friendly methods for viral disinfection. We found that heat (≤85 °C) under various humidities (≤100% relative humidity, RH) was the most promising, nondestructive method for the preservation of filtration properties in meltblown fabrics as well as N95-grade respirators. At 85 °C, 30% RH, we were able to perform 50 cycles of heat treatment without significant changes in the filtration efficiency. At low humidity or dry conditions, temperatures up to 100 °C were not found to alter the filtration efficiency significantly within 20 cycles of treatment. Ultraviolet (UV) irradiation was a secondary choice, which was able to withstand 10 cycles of treatment and showed small degradation by 20 cycles. However, UV can potentially impact the material strength and subsequent sealing of respirators. Finally, treatments involving liquids and vapors require caution, as steam, alcohol, and household bleach all may lead to degradation of the filtration efficiency, leaving the user vulnerable to the viral aerosols.


Assuntos
Desinfecção/métodos , Máscaras/normas , Dispositivos de Proteção Respiratória/normas , Desinfecção/normas , Calefação/métodos , Têxteis/normas
8.
Nature ; 579(7797): 41-50, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32132689

RESUMO

Tremendous progress in nanotechnology has enabled advances in the use of luminescent nanomaterials in imaging, sensing and photonic devices. This translational process relies on controlling the photophysical properties of the building block, that is, single luminescent nanoparticles. In this Review, we highlight the importance of single-particle spectroscopy in revealing the diverse optical properties and functionalities of nanomaterials, and compare it with ensemble fluorescence spectroscopy. The information provided by this technique has guided materials science in tailoring the synthesis of nanomaterials to achieve optical uniformity and to develop novel applications. We discuss the opportunities and challenges that arise from pushing the resolution limit, integrating measurement and manipulation modalities, and establishing the relationship between the structure and functionality of single nanoparticles.

9.
Nat Commun ; 11(1): 606, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001696

RESUMO

Manipulating liquids with tunable shape and optical functionalities in real time is important for electroactive flow devices and optoelectronic devices, but remains a great challenge. Here, we demonstrate electrotunable liquid sulfur microdroplets in an electrochemical cell. We observe electrowetting and merging of sulfur droplets under different potentiostatic conditions, and successfully control these processes via selective design of sulfiphilic/sulfiphobic substrates. Moreover, we employ the electrowetting phenomena to create a microlens based on the liquid sulfur microdroplets and tune its characteristics in real time through changing the shape of the liquid microdroplets in a fast, repeatable, and controlled manner. These studies demonstrate a powerful in situ optical battery platform for unraveling the complex reaction mechanism of sulfur chemistries and for exploring the rich material properties of the liquid sulfur, which shed light on the applications of liquid sulfur droplets in devices such as microlenses, and potentially other electrotunable and optoelectronic devices.

10.
Nat Nanotechnol ; 2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-31988508

RESUMO

It has recently been shown that sulfur, a solid material in its elementary form S8, can stay in a supercooled state as liquid sulfur in an electrochemical cell. We establish that this newly discovered state could have implications for lithium-sulfur batteries. Here, through in situ studies of electrochemical sulfur generation, we show that liquid (supercooled) and solid elementary sulfur possess very different areal capacities over the same charging period. To control the physical state of sulfur, we studied its growth on two-dimensional layered materials. We found that on the basal plane, only liquid sulfur accumulates; by contrast, at the edge sites, liquid sulfur accumulates if the thickness of the two-dimensional material is small, whereas solid sulfur nucleates if the thickness is large (tens of nanometres). Correlating the sulfur states with their respective areal capacities, as well as controlling the growth of sulfur on two-dimensional materials, could provide insights for the design of future lithium-sulfur batteries.

11.
Nat Nanotechnol ; 15(2): 131-137, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31907442

RESUMO

To date, effective control over the electrochemical reduction of CO2 to multicarbon products (C ≥ 2) has been very challenging. Here, we report a design principle for the creation of a selective yet robust catalytic interface for heterogeneous electrocatalysts in the reduction of CO2 to C2 oxygenates, demonstrated by rational tuning of an assembly of nitrogen-doped nanodiamonds and copper nanoparticles. The catalyst exhibits a Faradaic efficiency of ~63% towards C2 oxygenates at applied potentials of only -0.5 V versus reversible hydrogen electrode. Moreover, this catalyst shows an unprecedented persistent catalytic performance up to 120 h, with steady current and only 19% activity decay. Density functional theory calculations show that CO binding is strengthened at the copper/nanodiamond interface, suppressing CO desorption and promoting C2 production by lowering the apparent barrier for CO dimerization. The inherent compositional and electronic tunability of the catalyst assembly offers an unrivalled degree of control over the catalytic interface, and thereby the reaction energetics and kinetics.

12.
IEEE Trans Med Imaging ; 39(5): 1759-1766, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31804930

RESUMO

Conventional ultrasound imaging is based on the scattering of sound from inhomogeneities in the density and the speed of sound and is often used in medicine to resolve pathologic compared to normal tissue. Here we demonstrate a difference-frequency ultrasound (dfUS) imaging method that is based on the interaction of two sound pulses that propagate non-collinearly and intersect in space and time. The dfUS signal arises primarily from the second-order non-linear coefficient, a contrast mechanism that differs from linear and harmonic US imaging. The distinct contrast mechanism allows dfUS to image anatomic features that are not identifiable in conventional US images of salmon and pig kidney tissue. Further, dfUS produces enhanced contrast of glioblastoma tumor implanted in the mouse brain, revealing its potential for improving medical diagnosis. Progress towards a real-time system is discussed.

13.
Artigo em Inglês | MEDLINE | ID: mdl-31628456

RESUMO

OBJECTIVES: This study aims at contrasting the effects of limited future time perspective and mortality salience on goal prioritization across adulthood. Socioemotional selectivity theory (SST) argues that people increasingly prioritize emotionally meaningful goals when they perceive future time as more limited. Terror management theory (TMT) suggests that mortality salience (i.e. the awareness of one's mortality) drives people to prioritize the goal of perpetuating own existence through affirming cultural worldview. METHOD: In this study, participants (N = 438) were randomly assigned to 6 conditions that primed (1) limited future time, (2) mortality salience, (3) death reflection, (4) both limited future time and mortality salience, (5) both limited future time and death reflection, or (6) none. RESULTS: Results showed that older adults allocated significantly more resources to emotionally close recipients who supported their cultural worldviews in conditions involving future time limitation and death reflection. They also allocated less resources to emotionally not close recipients who did not support their cultural worldviews in conditions involving future time limitation. Younger adults did not show these differences. Nor did mortality salience have any effect. DISCUSSION: These results suggest that future time perspective and death reflection shift age-related goals more than mortality salience.

14.
J Am Chem Soc ; 141(42): 16997-17005, 2019 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-31592655

RESUMO

Upconverting nanoparticles provide valuable benefits as optical probes for bioimaging and Förster resonant energy transfer (FRET) due to their high signal-to-noise ratio, photostability, and biocompatibility; yet, making nanoparticles small yields a significant decay in brightness due to increased surface quenching. Approaches to improve the brightness of UCNPs exist but often require increased nanoparticle size. Here we present a unique core-shell-shell nanoparticle architecture for small (sub-20 nm), bright upconversion with several key features: (1) maximal sensitizer concentration in the core for high near-infrared absorption, (2) efficient energy transfer between core and interior shell for strong emission, and (3) emitter localization near the nanoparticle surface for efficient FRET. This architecture consists of ß-NaYbF4 (core) @NaY0.8-xErxGd0.2F4 (interior shell) @NaY0.8Gd0.2F4 (exterior shell), where sensitizer and emitter ions are partitioned into core and interior shell, respectively. Emitter concentration is varied (x = 1, 2, 5, 10, 20, 50, and 80%) to investigate influence on single particle brightness, upconversion quantum yield, decay lifetimes, and FRET coupling. We compare these seven samples with the field-standard core-shell architecture of ß-NaY0.58Gd0.2Yb0.2Er0.02F4 (core) @NaY0.8Gd0.2F4 (shell), with sensitizer and emitter ions codoped in the core. At a single particle level, the core-shell-shell design was up to 2-fold brighter than the standard core-shell design. Further, by coupling a fluorescent dye to the surface of the two different architectures, we demonstrated up to 8-fold improved emission enhancement with the core-shell-shell compared to the core-shell design. We show how, given proper consideration for emitter concentration, we can design a unique nanoparticle architecture to yield comparable or improved brightness and FRET coupling within a small volume.

15.
Artigo em Inglês | MEDLINE | ID: mdl-31251360

RESUMO

OBJECTIVES: Prior studies have found that as people age, they value low-arousal positive affect (LAP) to a greater extent and high-arousal positive affect (HAP) to a lower extent. We aimed to investigate whether actually achieving those ideal affects was related to better well-being outcomes, measured in terms of meaning in life. METHODS: Using a time sampling design across 14 days (N = 162), we investigated whether the experience of LAP and HAP was related to the experience of meaning in life and how these associations differed across younger and older adults in Hong Kong. RESULTS: Both LAP and HAP contributed to the experience of meaning in life for both younger and older adults. The global effect of LAP on meaning in life was stronger for older than younger adults, whereas the momentary effect of HAP on meaning in life was stronger for younger adults than older adults.

16.
ACS Nano ; 13(7): 7750-7758, 2019 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-31244043

RESUMO

Multimodality imaging involves the use of more imaging modes to image the same living subjects and is now generally preferred in clinics for cancer imaging. Here we present multimodality-Magnetic Particle Imaging (MPI), Magnetic Resonance Imaging (MRI), Photoacoustic, Fluorescent-nanoparticles (termed MMPF NPs) for imaging tumor xenografts in living mice. MMPF NPs provide long-term (more than 2 months), dynamic, and accurate quantification, in vivo, of NPs and in real time by MPI. Moreover, MMPF NPs offer ultrasensitive MPI imaging of tumors (the tumor ROI increased by 30.6 times over that of preinjection). Moreover, the nanoparticle possessed a long-term blood circulation time (half-life at 49 h) and high tumor uptake (18% ID/g). MMPF NPs have been demonstrated for imaging breast and brain tumor xenografts in both subcutaneous and orthotopic models in mice via simultaneous MPI, MRI, fluorescence, and photoacoustic imaging with excellent tumor contrast to normal tissues.

17.
Nat Nanotechnol ; 14(5): 420-425, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30833691

RESUMO

Electron microscopy has been instrumental in our understanding of complex biological systems. Although electron microscopy reveals cellular morphology with nanoscale resolution, it does not provide information on the location of different types of proteins. An electron-microscopy-based bioimaging technology capable of localizing individual proteins and resolving protein-protein interactions with respect to cellular ultrastructure would provide important insights into the molecular biology of a cell. Here, we synthesize small lanthanide-doped nanoparticles and measure the absolute photon emission rate of individual nanoparticles resulting from a given electron excitation flux (cathodoluminescence). Our results suggest that the optimization of nanoparticle composition, synthesis protocols and electron imaging conditions can lead to sub-20-nm nanolabels that would enable high signal-to-noise localization of individual biomolecules within a cellular context. In ensemble measurements, these labels exhibit narrow spectra of nine distinct colours, so the imaging of biomolecules in a multicolour electron microscopy modality may be possible.


Assuntos
Corantes Fluorescentes/química , Microscopia Eletrônica de Transmissão , Nanopartículas/química
18.
Proc Natl Acad Sci U S A ; 116(3): 765-770, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30602455

RESUMO

Supercooled liquid sulfur microdroplets were directly generated from polysulfide electrochemical oxidation on various metal-containing electrodes. The sulfur droplets remain liquid at 155 °C below sulfur's melting point (T m = 115 °C), with fractional supercooling change (T m - T sc)/T m larger than 0.40. In operando light microscopy captured the rapid merging and shape relaxation of sulfur droplets, indicating their liquid nature. Micropatterned electrode and electrochemical current allow precise control of the location and size of supercooled microdroplets, respectively. Using this platform, we initiated and observed the rapid solidification of supercooled sulfur microdroplets upon crystalline sulfur touching, which confirms supercooled sulfur's metastability at room temperature. In addition, the formation of liquid sulfur in electrochemical cell enriches lithium-sulfur-electrolyte phase diagram and potentially may create new opportunities for high-energy Li-S batteries.

19.
Community Dent Oral Epidemiol ; 47(2): 134-141, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30456882

RESUMO

OBJECTIVES: To describe the associations between chewing function with oral health and certain general health characteristics, in a population of community-dwelling older Australian men. METHODS: Analysis of data obtained from a cross-sectional analysis of the 4th wave of the Concord Health and Ageing in Men Project cohort of 614 participants, 524 whom were dentate, aged 78 years and over. Their chewing capacity was assessed using three main indicators: capacity to chew eleven food items ranging from boiled eggs through to fresh carrots and nuts; discomfort when eating; and interruption of meals. Associations with chewing were tested for dentate vs edentate participants, numbers of teeth present, active dental disease and key general health conditions such as disabilities, comorbidities and cognitive status. Log binomial regression models adjusted for age, country of birth, income, education and marital status. Prevalence ratios and 95% confidence intervals were estimated. RESULTS: Twenty-one per cent of participants could not eat hard foods, while 23.1% reported discomfort when eating, and 8.8% reported interrupted meals when eating. There was a threefold difference in the capacity of dentate men to chew firm meat over that of edentulous men (95% CI, 2.0-4.9); a 2.5 times greater likelihood of edentate men reporting discomfort when eating (95% CI: 1.5-4.3); and 1.9 times greater likelihood of edentate participants reporting having meals interrupted (95% CI: 1.4-2.6). Chewing/eating difficulties were associated with both dental status (number of teeth, active dental caries) and self-rated dental health. Fewer than 20 teeth and the presence of active coronal or root decay were associated with more discomfort when eating. General health conditions associated with chewing function included disability, physical activity, comorbidities, cognitive status and depression. Older men's self-rated oral health and general health perceptions were also associated with aspects of chewing function. Poorer self-reported oral health was associated with inability to eat hard foods (95% CI: 1.3-2.7) and with discomfort when eating (95% CI: 2.6-5.1), while poorer self-reported general health was associated with discomfort when eating (95% CI: 1.2-2.2). CONCLUSIONS: Falling rates of edentulism may lead to improved chewing and eating function in older men. Maintaining 20 or more natural teeth, and preventing active coronal and root caries should enhance chewing function and promote self-reported health and oral health. Lower capacity to chew hard foods and a higher reporting of discomfort when eating is associated with co-morbidity in older Australian men.


Assuntos
Cárie Dentária , Dentição , Mastigação/fisiologia , Boca Edêntula/complicações , Perda de Dente/complicações , Idoso , Envelhecimento , Austrália , Estudos Transversais , Humanos , Masculino , Boca Edêntula/epidemiologia , Saúde Bucal , Perda de Dente/epidemiologia
20.
IEEE Trans Med Imaging ; 38(1): 107-112, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30028694

RESUMO

We measured the reduction of speckle by frequency compounding using Gaussian pulses, which have the least time-bandwidth product. The experimental results obtained from a tissue mimicking phantom agree quantitatively with numerical simulations of randomly distributed point scatterers. For a fixed axial resolution, the amount of speckle reduction is found to approach a maximum as the number of bands increases while the total spectral range that they cover is kept constant. An analytical solution of the maximal speckle reduction is derived and shows that the maximum improves approximately as the inverse square root of the Gaussian pulse bandwidth. Since the axial resolution is proportional to the inverse of the pulse bandwidth, an optimized trade-off between speckle reduction and axial resolution is obtained. Considerations for the applications of the optimized trade-off are discussed.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Ultrassonografia/métodos , Artefatos , Imagens de Fantasmas
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