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1.
Micromachines (Basel) ; 15(7)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-39064338

RESUMO

Graphite is a versatile material used in various fields, particularly in the power source manufacturing industry. Nowadays, graphite holds a unique position in materials for anode electrodes in lithium-ion batteries. With a carbon content of over 99% being a requirement for graphite to serve as an electrode material, the graphite refinement process plays a pivotal role in the research and development of anode materials for lithium-ion batteries. This study used three different processes to purify spherical graphite through wet chemical methods. The spherical graphite after the purification processes was analysed for carbon content by using energy-dispersive X-ray (EDX) spectroscopy and was evaluated for structural and morphological characteristics through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses. The analyses results indicate that the three-step process via H2SO4-NaOH-HCl cleaning can elevate the carbon content from 90% to above 99.9% while still maintaining the graphite structure and spherical morphology, thus enhancing the surface area of the material for anode application. Furthermore, the spherical graphite was studied for electrochemical properties when used as an anode for Li-ion batteries using cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements. The results demonstrated that the purification process significantly improves the material's capacity with a specific capacity of 350 mAh/g compared to the 280 mAh/g capacity of the anode made of spherical graphite without purification.

2.
Biochem Biophys Res Commun ; 733: 150430, 2024 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-39043000

RESUMO

It raises questions about the impact of lard on the health and the differences in individual responses. Therefore, we developed a model of mice fed with high fat (HF) from lard in 130 days. The weight of the mice was measured every two days. Glucose tolerance test and insulin tolerance tests were performed at 70 days and 130 days of experiment. At the end of the study, the fat tissue was collected to check the weight, and a blood sample was collected to check the blood lipids and liver enzymes. Surprisingly, mice responded variously to the HF by being classified into two groups, one group had significantly high gained weight (HG_HF) versus the mice fed a standard diet (STD) (p < 0.001), and another group (LG_HF) has not difference in body weight compared to the STD groups. This phenomenon in body weight is directly reflected by the white fat accumulation, but not by brown fat. Eating HF from lard for a long time can disrupt glucose tolerance and cause dyslipidemia in mice, even in the LG_HF group, but can not disrupt insulin tolerance and cause liver enzyme disorders. In summary, our findings are a wake-up call for many cases where eating HF from lard does not gain weight and not increase the white fat storage, but still has the potential to cause adverse health effects. Further studies are encouraged to understand the molecular mechanisms that causes the body to regulate its weight and responses when eating HF from lard, especially in the LG_HF group.

3.
Diagnostics (Basel) ; 14(12)2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38928697

RESUMO

In the study of coronary artery disease (CAD), the mechanism of plaque formation and development is still an important subject for investigation. A limitation of current coronary angiography (CAG) is that it can only show static images of the narrowing of arterial channels without identifying the mechanism of the disease or predicting its progression or regression. To address this limitation, the CAG technique has been modified. The new approach emphasizes identifying and analyzing blood flow patterns, employing methodologies akin to those used by hydraulic engineers for fluid or gas movement through domestic or industrial pipes and pumps. With the new technique, various flow patterns and arterial phenomena-such as laminar, turbulent, antegrade, retrograde, and recirculating flow and potentially water hammer shock and vortex formation-are identified, recorded, and classified. These phenomena are then correlated with the presence of lesions at different locations within the coronary vasculature. The formation and growth of these lesions are explained from the perspective of fluid mechanics. As the pathophysiology of CAD and other cardiovascular conditions becomes clearer, new medical, surgical, and interventional treatments could be developed to reverse abnormal coronary flow dynamics and restore laminar flow, leading to improved clinical outcomes.

4.
HLA ; 103(4): e15490, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38634568

RESUMO

The presence of multiple donor-specific antibodies (DSAs) targeting HLA antigens poses a challenge to transplantation. Various techniques, including the use of recombinant cell lines and crossmatch cells have been developed to isolate DSAs. To simplify the extraction of HLA-specific DSAs from complex sera, we introduced magnetic beads with single HLA specificity (MagSort). Sera were treated with MagSort, allowing HLA-specific antibodies to bind to the beads, and these specific antibodies were subsequently eluted. MagSort beads, coated with 59 different HLA variants, underwent testing through 1329 adsorption/elution processes, demonstrating their effectiveness and specificity in adsorbing and eluting HLA-specific antibodies. The MagSort method proves comparable to the cell method, showing similar isolated antibody binding patterns. The isolated antibody binding patterns from MagSort reveal both known eplets and unknown patterns, suggesting its utility for eplet discovery. Additionally, MagSort proved effective in extracting signals for flow cytometry cross-matching, offering a means to assess the binding capability of isolated antibodies against specific donor cells.


Assuntos
Anticorpos , Antígenos HLA , Humanos , Alelos , Teste de Histocompatibilidade/métodos , Fenômenos Magnéticos , Isoanticorpos , Rejeição de Enxerto
5.
Sci Adv ; 10(12): eadk1278, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38507481

RESUMO

Studying placental functions is crucial for understanding pregnancy complications. However, imaging placenta is challenging due to its depth, volume, and motion distortions. In this study, we have developed an implantable placenta window in mice that enables high-resolution photoacoustic and fluorescence imaging of placental development throughout the pregnancy. The placenta window exhibits excellent transparency for light and sound. By combining the placenta window with ultrafast functional photoacoustic microscopy, we were able to investigate the placental development during the entire mouse pregnancy, providing unprecedented spatiotemporal details. Consequently, we examined the acute responses of the placenta to alcohol consumption and cardiac arrest, as well as chronic abnormalities in an inflammation model. We have also observed viral gene delivery at the single-cell level and chemical diffusion through the placenta by using fluorescence imaging. Our results demonstrate that intravital imaging through the placenta window can be a powerful tool for studying placenta functions and understanding the placental origins of adverse pregnancy outcomes.


Assuntos
Placenta , Placentação , Gravidez , Feminino , Camundongos , Animais , Placenta/diagnóstico por imagem , Microscopia/métodos , Imagem Óptica , Microscopia Intravital
6.
Artigo em Inglês | MEDLINE | ID: mdl-38335991

RESUMO

BACKGROUND: This study presents the early and midterm outcomes of combining atrial fibrillation (AF) treatment with minimally invasive mitral valve surgery (MIMVS) at our center. METHODS: From January 2017 to June 2022, our center treated a total of 86 patients with both MIMVS and surgical AF ablation. The patient cohort included 62 women (72.1%) and 24 men (27.9%). The average EuroScore II was 2.64 ± 1.49%, and the patients were followed up for an average period of 46.31 ± 9.84 months. RESULTS: Postoperatively, 95.3% of patients experienced a change in sinus rhythm, and 86.2% were discharged in sinus rhythm. The hospital's mortality rate was 2.3%, with a late mortality rate of 3.5%. Survival analysis revealed an atrial fibrillation-free 5-year follow-up rate of 59.1 ± 9.1%. The 5-year survival rate was 92.7 ± 3.3%. CONCLUSION: Our 5-year experience demonstrates that the combination of MIMVS and surgical AF ablation can be routinely performed with favorable peri- and postoperative outcomes. This reflects our hospital's culture and guidance on patient selection, particularly when adopting minimally invasive approaches for multiple procedures.

7.
IEEE Trans Med Imaging ; 43(2): 771-783, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37773898

RESUMO

In photoacoustic computed tomography (PACT) with short-pulsed laser excitation, wideband acoustic signals are generated in biological tissues with frequencies related to the effective shapes and sizes of the optically absorbing targets. Low-frequency photoacoustic signal components correspond to slowly varying spatial features and are often omitted during imaging due to the limited detection bandwidth of the ultrasound transducer, or during image reconstruction as undesired background that degrades image contrast. Here we demonstrate that low-frequency photoacoustic signals, in fact, contain functional and molecular information, and can be used to enhance structural visibility, improve quantitative accuracy, and reduce spare-sampling artifacts. We provide an in-depth theoretical analysis of low-frequency signals in PACT, and experimentally evaluate their impact on several representative PACT applications, such as mapping temperature in photothermal treatment, measuring blood oxygenation in a hypoxia challenge, and detecting photoswitchable molecular probes in deep organs. Our results strongly suggest that low-frequency signals are important for functional and molecular PACT.


Assuntos
Técnicas Fotoacústicas , Imagens de Fantasmas , Técnicas Fotoacústicas/métodos , Tomografia Computadorizada por Raios X/métodos , Processamento de Imagem Assistida por Computador , Análise Espectral
8.
Environ Res ; 241: 117633, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37980997

RESUMO

Air pollution poses a threat to children's respiratory health. This study aims to quantify the association between short-term air pollution exposure and respiratory hospital admissions among children in Hanoi, Vietnam, and estimate the population-attributable burden using local data. A case-crossover analysis was conducted based on the individual records where each case is their own control. The health data was obtained from 13 hospitals in Hanoi and air pollution data was collected from four monitoring stations from 2007 to 2019. We used conditional logistic regression to estimate Percentage Change (PC) and 95% Confidence Interval (CI) in odd of hospital admissions per 10 µg/m3 increase in daily average particulate matter (e.g. PM1, PM2.5, PM10), Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), 8-h maximum Ozone and per 1000 µg/m3 increase in daily mean of Carbon Monoxide (CO). We also calculated the number and fraction of admissions attributed to air pollution in Hanoi by using the coefficient at lag 0. A 10 µg/m3 increase in the concentration of PM10, PM2.5, PM1, SO2, NO2, O3 8-h maximum and 1000 µg/m3 increase in CO concentration was associated with 0.6%, 1.2%, 1.4%, 0.8%, 1.6%, 0.3%, and 1.7% increase in odd of admission for all respiratory diseases among children under 16 years at lag 0-2. All PM metrics and NO2 are associated with childhood admission for pneumonia and bronchitis. Admissions due to asthma and upper respiratory diseases are related to increments in NO2 and CO. For attributable cases, PM2.5 concentrations in Hanoi exceeding the World Health Organization Air Quality Guidelines accounted for 1619 respiratory hospital admissions in Hanoi children in 2019. Our findings show that air pollution has a detrimental impact on the respiratory health of Hanoi children and there will be important health benefits from improved air quality management planning to reduce air pollution in Vietnam.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Transtornos Respiratórios , Doenças Respiratórias , Criança , Humanos , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio/análise , Poluição do Ar/análise , Doenças Respiratórias/induzido quimicamente , Doenças Respiratórias/epidemiologia , Material Particulado/análise , Transtornos Respiratórios/induzido quimicamente , Transtornos Respiratórios/epidemiologia , Hospitais , China
9.
Science ; 382(6675): 1148-1155, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38060634

RESUMO

Volumetric printing, an emerging additive manufacturing technique, builds objects with enhanced printing speed and surface quality by forgoing the stepwise ink-renewal step. Existing volumetric printing techniques almost exclusively rely on light energy to trigger photopolymerization in transparent inks, limiting material choices and build sizes. We report a self-enhancing sonicated ink (or sono-ink) design and corresponding focused-ultrasound writing technique for deep-penetration acoustic volumetric printing (DAVP). We used experiments and acoustic modeling to study the frequency and scanning rate-dependent acoustic printing behaviors. DAVP achieves the key features of low acoustic streaming, rapid sonothermal polymerization, and large printing depth, enabling the printing of volumetric hydrogels and nanocomposites with various shapes regardless of their optical properties. DAVP also allows printing at centimeter depths through biological tissues, paving the way toward minimally invasive medicine.

10.
Int J Public Health ; 68: 1606238, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37881770

RESUMO

Objectives: This paper explores the potential reduction in the number of deaths and the corresponding economic benefits in Vietnam that could have arisen from the decreased in concentrations of particulate matter with a diameter of 2.5 µm or less (PM2.5) and nitrogen dioxide (NO2). Methods: Using Global Exposure Mortality Models, we estimated the potential health and economic benefits on people aged 25 and above across Vietnam's 63 provinces. The counterfactual scenario assumed reducing PM2.5 and NO2 concentrations to levels observed during the two COVID-19 epidemic waves in 2021 with national lockdowns and activity restrictions. Results: In 2019, PM2.5 concentrations ranged from 12.8 to 40.8 µg/m3 while NO2 concentrations ranged between 2.9 and 36.98 µg/m3. The reduced levels of PM2.5 and NO2 resulted in 3,807 (95% CI: 2,845-4,730) and 2,451 (95% CI: 2,845-4,730) avoided deaths of adults aged 25 and above due to non-injury-related causes, respectively. Considering that every prevented death represents potential tangible and intangible cost savings, reduced levels of PM2.5 and NO2 concentrations during COVID-19 restrictions would have resulted in economic benefits of $793.0 million (95% CI: 592.7-985.4) and $510.6 million (95% CI: 381.3-634.9), respectively. Conclusion: The COVID-19 lockdown led to decreased PM2.5 and NO2 concentrations, benefiting health and economy in Vietnam. Our findings highlight the potential advantages of implementing air quality control policies in the country.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , COVID-19 , Adulto , Humanos , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio , Vietnã/epidemiologia , Exposição Ambiental/análise , Poluição do Ar/análise , Material Particulado/análise , COVID-19/epidemiologia , COVID-19/prevenção & controle
11.
ArXiv ; 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37576129

RESUMO

In photoacoustic computed tomography (PACT) with short-pulsed laser excitation, wideband acoustic signals are generated in biological tissues with frequencies related to the effective shapes and sizes of the optically absorbing targets. Low-frequency photoacoustic signal components correspond to slowly varying spatial features and are often omitted during imaging due to the limited detection bandwidth of the ultrasound transducer, or during image reconstruction as undesired background that degrades image contrast. Here we demonstrate that low-frequency photoacoustic signals, in fact, contain functional and molecular information, and can be used to enhance structural visibility, improve quantitative accuracy, and reduce spare-sampling artifacts. We provide an in-depth theoretical analysis of low-frequency signals in PACT, and experimentally evaluate their impact on several representative PACT applications, such as mapping temperature in photothermal treatment, measuring blood oxygenation in a hypoxia challenge, and detecting photoswitchable molecular probes in deep organs. Our results strongly suggest that low-frequency signals are important for functional and molecular PACT.

12.
ArXiv ; 2023 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-37547654

RESUMO

Photoacoustic computed tomography (PACT) is a proven technology for imaging hemodynamics in deep brain of small animal models. PACT is inherently compatible with ultrasound (US) imaging, providing complementary contrast mechanisms. While PACT can quantify the brain's oxygen saturation of hemoglobin (sO2), US imaging can probe the blood flow based on the Doppler effect. Further, by tracking gas-filled microbubbles, ultrasound localization microscopy (ULM) can map the blood flow velocity with sub-diffraction spatial resolution. In this work, we present a 3D deep-brain imaging system that seamlessly integrates PACT and ULM into a single device, 3D-PAULM. Using a low ultrasound frequency of 4 MHz, 3D-PAULM is capable of imaging the whole-brain hemodynamic functions with intact scalp and skull in a totally non-invasive manner. Using 3D-PAULM, we studied the mouse brain functions with ischemic stroke. Multi-spectral PACT, US B-mode imaging, microbubble-enhanced power Doppler (PD), and ULM were performed on the same mouse brain with intrinsic image co-registration. From the multi-modality measurements, we future quantified blood perfusion, sO2, vessel density, and flow velocity of the mouse brain, showing stroke-induced ischemia, hypoxia, and reduced blood flow. We expect that 3D-PAULM can find broad applications in studying deep brain functions on small animal models.

13.
J Vis Exp ; (196)2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-37335115

RESUMO

Presented here is an experimental ischemic stroke study using our newly developed noninvasive imaging system that integrates three acoustic-based imaging technologies: photoacoustic, ultrasound, and angiographic tomography (PAUSAT). Combining these three modalities helps acquire multi-spectral photoacoustic tomography (PAT) of the brain blood oxygenation, high-frequency ultrasound imaging of the brain tissue, and acoustic angiography of the cerebral blood perfusion. The multi-modal imaging platform allows the study of cerebral perfusion and oxygenation changes in the whole mouse brain after stroke. Two commonly used ischemic stroke models were evaluated: the permanent middle cerebral artery occlusion (pMCAO) model and the photothrombotic (PT) model. PAUSAT was used to image the same mouse brains before and after a stroke and quantitatively analyze both stroke models. This imaging system was able to clearly show the brain vascular changes after ischemic stroke, including significantly reduced blood perfusion and oxygenation in the stroke infarct region (ipsilateral) compared to the uninjured tissue (contralateral). The results were confirmed by both laser speckle contrast imaging and triphenyltetrazolium chloride (TTC) staining. Furthermore, stroke infarct volume in both stroke models was measured and validated by TTC staining as the ground truth. Through this study, we have demonstrated that PAUSAT can be a powerful tool in noninvasive and longitudinal preclinical studies of ischemic stroke.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Animais , Camundongos , Isquemia Encefálica/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Encéfalo/irrigação sanguínea , Acidente Vascular Cerebral/diagnóstico por imagem , Infarto da Artéria Cerebral Média/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Ultrassonografia , Angiografia , Neuroimagem , Modelos Animais de Doenças
14.
Anesthesiology ; 139(2): 173-185, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37079748

RESUMO

BACKGROUND: The administration of epinephrine after severe refractory hypotension, shock, or cardiac arrest restores systemic blood flow and major vessel perfusion but may worsen cerebral microvascular perfusion and oxygen delivery through vasoconstriction. The authors hypothesized that epinephrine induces significant microvascular constriction in the brain, with increased severity after repetitive dosing and in the aged brain, eventually leading to tissue hypoxia. METHODS: The authors investigated the effects of intravenous epinephrine administration in healthy young and aged C57Bl/6 mice on cerebral microvascular blood flow and oxygen delivery using multimodal in vivo imaging, including functional photoacoustic microscopy, brain tissue oxygen sensing, and follow-up histologic assessment. RESULTS: The authors report three main findings. First, after epinephrine administration, microvessels exhibited severe immediate vasoconstriction (57 ± 6% of baseline at 6 min, P < 0.0001, n = 6) that outlasted the concurrent increase in arterial blood pressure, while larger vessels demonstrated an initial increase in flow (108 ± 6% of baseline at 6 min, P = 0.02, n = 6). Second, oxyhemoglobin decreased significantly within cerebral vessels with a more pronounced effect in smaller vessels (microvessels to 69 ± 8% of baseline at 6 min, P < 0.0001, n = 6). Third, oxyhemoglobin desaturation did not indicate brain hypoxia; on the contrary, brain tissue oxygen increased after epinephrine application (from 31 ± 11 mmHg at baseline to 56 ± 12 mmHg, 80% increase, P = 0.01, n = 12). In the aged brains, microvascular constriction was less prominent yet slower to recover compared to young brains, but tissue oxygenation was increased, confirming relative hyperoxia. CONCLUSIONS: Intravenous application of epinephrine induced marked cerebral microvascular constriction, intravascular hemoglobin desaturation, and paradoxically, an increase in brain tissue oxygen levels, likely due to reduced transit time heterogeneity.


Assuntos
Microscopia , Oxiemoglobinas , Camundongos , Animais , Microcirculação , Oxiemoglobinas/farmacologia , Epinefrina/farmacologia , Oxigênio , Circulação Cerebrovascular
15.
Radiol Case Rep ; 18(4): 1605-1609, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36852290

RESUMO

Traumatic rupture of the thoracic aorta is a rare condition, with a high mortality rate. Over the last 2 decades, strategies for managing aortic injury caused by blunt chest trauma have changed substantially, resulting in significantly improved outcomes. The recent development of endovascular repair offers a less invasive alternative to conventional open repair, particularly in patients with multiple injuries. Here, we report the case of a 31-year-old man who was referred to our emergency department with blunt chest trauma following a motorcycle-truck collision. Computed tomography confirmed acute traumatic rupture of the thoracic aorta, and the patient was successfully treated with endovascular repair.

16.
Photoacoustics ; 29: 100444, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36620854

RESUMO

We present an ischemic stroke study using our newly-developed PAUSAT system that integrates photoacoustic computed tomography (PACT), high-frequency ultrasound imaging, and acoustic angiographic tomography. PAUSAT is capable of three-dimensional (3D) imaging of the brain morphology, blood perfusion, and blood oxygenation. Using PAUSAT, we studied the hemodynamic changes in the whole mouse brain induced by two common ischemic stroke models: the permanent middle cerebral artery occlusion (pMCAO) model and the photothrombotic (PT) model. We imaged the same mouse brains before and after stroke, and quantitatively compared the two stroke models. We observed clear hemodynamic changes after ischemic stroke, including reduced blood perfusion and oxygenation. Such changes were spatially heterogenous. We also quantified the tissue infarct volume in both stroke models. The PAUSAT measurements were validated by laser speckle imaging and histology. Our results have collectively demonstrated that PAUSAT can be a valuable tool for non-invasive longitudinal studies of neurological diseases at the whole-brain scale.

17.
Front Public Health ; 10: 1056370, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36466445

RESUMO

Introduction and objectives: Studies assessing the health benefits of air pollution reduction in Vietnam are scarce. This study quantified the annual mortality burden due to PM2.5 pollution in Vietnam above the World Health Organization recommendation for community health (AQG: 5 µg/m3) and the proposed National Technical Regulation on Ambient Air Quality (proposed QCVN: 15 µg/m3). Methodology: This study applied a health impact assessment methodology with the hazard risk function for non-communicable diseases (NCDs) and lower respiratory infections (LRIs) in the Global Exposure Mortality Model (GEMM) to calculate attributable deaths, Years of Life lost, and Loss of Life expectancy at birth due to air pollution in the Vietnamese population above 25 years of age in 11 provinces. We obtained annual average PM2.5 concentrations for Vietnam in 2019 at a 3x3 km grid modeled using Mixed Linear regression and multi-data sources. Population and baseline mortality data were obtained from administrative data system in Vietnam. We reported the findings at both the provincial and smaller district levels. Results: Annual PM2.5 concentrations in all studied provinces exceeded both the AQG and the proposed QCVN. The maximum annual number of attributable deaths in the studied provinces if they had complied with WHO air quality guidelines was in Ha Noi City, with 5,090 (95%CI: 4,253-5,888) attributable deaths. At the district level, the highest annual rate of attributable deaths if the WHO recommendation for community health had been met was 104.6 (95%CI: 87.0-121.5) attributable deaths per 100,000 population in Ly Nhan (Ha Nam province). Conclusion: A much larger number of premature deaths in Vietnam could potentially be avoided by lowering the recommended air quality standard. These results highlight the need for effective clean air action plans by local authorities to reduce air pollution and improve community health.


Assuntos
Poluição do Ar , Material Particulado , Recém-Nascido , Humanos , Vietnã/epidemiologia , Expectativa de Vida , Saúde Pública
18.
Science ; 378(6626): 1315-1320, 2022 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-36548427

RESUMO

Transparency in animals is a complex form of camouflage involving mechanisms that reduce light scattering and absorption throughout the organism. In vertebrates, attaining transparency is difficult because their circulatory system is full of red blood cells (RBCs) that strongly attenuate light. Here, we document how glassfrogs overcome this challenge by concealing these cells from view. Using photoacoustic imaging to track RBCs in vivo, we show that resting glassfrogs increase transparency two- to threefold by removing ~89% of their RBCs from circulation and packing them within their liver. Vertebrate transparency thus requires both see-through tissues and active mechanisms that "clear" respiratory pigments from these tissues. Furthermore, glassfrogs' ability to regulate the location, density, and packing of RBCs without clotting offers insight in metabolic, hemodynamic, and blood-clot research.


Assuntos
Anuros , Mimetismo Biológico , Coagulação Sanguínea , Eritrócitos , Fígado , Animais , Eritrócitos/citologia , Eritrócitos/fisiologia , Hemodinâmica , Fígado/fisiologia , Anuros/anatomia & histologia , Anuros/sangue , Anuros/fisiologia , Mimetismo Biológico/fisiologia , Fenômenos Ópticos , Contagem de Eritrócitos
19.
Photoacoustics ; 28: 100417, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36299642

RESUMO

Combining focused optical excitation and high-frequency ultrasound detection, optical-resolution photoacoustic microscopy (OR-PAM) can provide micrometer-level spatial resolution with millimeter-level penetration depth and has been employed in a variety of biomedical applications. However, it remains a challenge for OR-PAM to achieve a high imaging speed and a large field of view at the same time. In this work, we report a new approach to implement high-speed wide-field OR-PAM, using a cylindrically-focused transparent ultrasound transducer (CFT-UT). The CFT-UT is made of transparent lithium niobate coated with indium-tin-oxide as electrodes. A transparent cylindrical lens is attached to the transducer surface to provide an acoustic focal line with a length of 9 mm. The excitation light can pass directly through the CFT-UT from the above and thus enables a reflection imaging mode. High-speed imaging is achieved by fast optical scanning of the focused excitation light along the CFT-UT focal line. With the confocal alignment of the optical excitation and acoustic detection, a relatively high detection sensitivity is maintained over the entire scanning range. The CFT-UT-based OR-PAM system has achieved a cross-sectional frame rate of 500 Hz over the scanning range of 9 mm. We have characterized the system's performance on phantoms and demonstrated its application on small animal models in vivo. We expect the new CFT-UT-based OR-PAM will find matched biomedical applications that need high imaging speed over a large field of view.

20.
Nat Commun ; 13(1): 2813, 2022 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-35589810

RESUMO

Optogenetic manipulation and optical imaging in the near-infrared range allow non-invasive light-control and readout of cellular and organismal processes in deep tissues in vivo. Here, we exploit the advantages of Rhodopseudomonas palustris BphP1 bacterial phytochrome, which incorporates biliverdin chromophore and reversibly photoswitches between the ground (740-800 nm) and activated (620-680 nm) states, to generate a loxP-BphP1 transgenic mouse model. The mouse enables Cre-dependent temporal and spatial targeting of BphP1 expression in vivo. We validate the optogenetic performance of endogenous BphP1, which in the activated state binds its engineered protein partner QPAS1, to trigger gene transcription in primary cells and living mice. We demonstrate photoacoustic tomography of BphP1 expression in different organs, developing embryos, virus-infected tissues and regenerating livers, with the centimeter penetration depth. The transgenic mouse model provides opportunities for both near-infrared optogenetics and photoacoustic imaging in vivo and serves as a source of primary cells and tissues with genomically encoded BphP1.


Assuntos
Técnicas Fotoacústicas , Fitocromo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Camundongos , Camundongos Transgênicos , Optogenética/métodos , Fitocromo/genética , Fitocromo/metabolismo
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