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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3969-3972, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018869

RESUMO

The assessment of lower limb oedema almost always involves measuring leg volume, and the gold-standard for this is the water displacement technique. As it is not very practical to use in a clinical routine, physicians prefer indirect methods such as anthropometric or bioimpedance measurements. In the case of "non-pitting" leg oedema, i.e. where the presence of oedema is not obvious, it may be challenging to estimate changes in leg volume using these methods separately. The combination of these two methods, however, gives interesting results, such as a new composite parameter that is much more robust and efficient than commonly used parameters.Clinical Relevance- This study demonstrates the benefit of using a composite anthropometric-impedimetric parameter to predict water displacement variations in the leg over the course of a day, rather than using parameters based solely on anthropometry or impedance. Our new parameter (C²-A²)/R0 showed a robust r² value of 61%, which is more than twice the r² values obtained using other simple or composite parameters.


Assuntos
Perna (Membro) , Água , Antropometria , Edema/diagnóstico , Humanos , Extremidade Inferior , Análise Espectral
2.
J Environ Qual ; 49(3): 762-768, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016392

RESUMO

Sulfur (S) and sulfate (SO4 2- ) in fine particulate matter (PM2.5 ) are monitored by the Interagency Monitoring of Protected Visual Environments (IMPROVE) network at remote and rural sites across the United States. Within the IMPROVE network, S is determined from X-ray fluorescence (XRF) spectroscopy from a Teflon filter, and SO4 2- is determined via ion chromatography (IC) from a nylon filter. Differences in S and SO4 2- estimates may indicate the presence of organosulfur (OS) species or biases between sampling and analytical methods. To reduce potential biases, an inductively coupled plasma-optical emission spectroscopy (ICP-OES) method was developed to allow for analysis of SO4 2- and S from a single filter extract. Sulfur (ICP-OES) and SO4 2- (IC) estimates from 2016 IMPROVE filters correlated strongly, suggesting that, on average, ICP-OES accurately estimated S. However, observed differences between slopes suggested the presence of water-soluble OS species, especially during summer. Organosulfur species are important indicators of secondary organic aerosols formed through reactions of biogenic and anthropogenic pollutants and can be quantified through laboratory techniques such as reverse-phase liquid chromatography (RPLC) or hydrophilic liquid interaction chromatography (HILIC) coupled to electrospray ionization-high-resolution tandem mass spectrometry (RPLC/ESI-HR-MS/MS and HILIC/ESI-HR-MS/MS, respectively), and field techniques using Aerodyne aerosol mass spectrometry (AMS). However, these methods are costly and introduce relatively large uncertainties when scaled for large networks such as IMPROVE. The method described in this report provides an inexpensive complement to XRF, which measures total S (insoluble and water-soluble S) to estimate water-soluble S and OS concentrations in PM.


Assuntos
Nylons , Espectrometria de Massas em Tandem , Aerossóis , Análise Espectral , Enxofre , Estados Unidos
3.
Stomatologiia (Mosk) ; 99(5): 11-18, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33034171

RESUMO

PURPOSE OF THE STUDY: The aim of the work is a spectroscopic investigation and comparison of the molecular composition of dentine and gingival fluids as well as of their diagnostic potential for the preventive screening of dentin caries. MATERIAL AND METHODS: Applying infrared spectroscopy including synchrotron radiation the samples of biological fluids taken from the oral cavity (dentine fluid, fluid from the gingival sulcus and blood) were studied for the patients with the progressive dentine caries. The part of this research was undertaken with the infrared microspectroscopy beamline at the Australian Synchrotron. RESULTS: Dentine and gingival fluids were shown to have no less complicated composition than the blood serum. Having all this in mind, in spite that these two fluids are derivatives of the blood serum, and a majority of the molecular groups observed in all of the three fluids can be detected in their IR-spectra, it follows that there is a number of signature modes that are in fact present in the IR spectra of only dentine and gingival fluids. This fact indicates at the molecular exchange between them under certain conditions. It means the high diagnostic potential in the study of the pathologic processes occurring in the oral fluid of a human. We have observed and fixed an increase of thiocyanates and esters in the samples of both dentine and gingival fluids under the development of dentin caries. CONCLUSION: Utilization of the gingival fluid for screening taking into account that its sampling is not such a complicated challenge as dentine fluid sampling will promote a transition to the personalized medicine, the development of high-technology healthcare and technology of the health preservation as a whole.


Assuntos
Cárie Dentária , Dentina , Austrália , Cárie Dentária/diagnóstico , Cárie Dentária/prevenção & controle , Gengiva , Humanos , Análise Espectral
4.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1911-1914, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018375

RESUMO

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


Assuntos
Técnicas Fotoacústicas , Testes Diagnósticos de Rotina , Lasers , Luz , Análise Espectral
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1915-1918, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018376

RESUMO

High intensity focused ultrasound (HIFU) is a noninvasive therapy used to induce tissue ablation for treating malignant tissues. Photoacoustic (PA) has recently been proposed as an alternative method to guide HIFU. In this paper, we present a method of HIFU guided by time-reversing the transcranial PA signals of an optically selective target in a nonselective background. To improve the focus performance on target area, we further propose to utilize the time-reversed PA signals as the initial population of Genetic Algorithm (GA) to optimize the focusing iteratively. In particular, we mimic both optical and acoustic parameters of the human brain and intracranial media in the simulation study. Experimental results show that the focusing accuracy of the proposed method has been significantly improved compared to just one-step PA time-reversal. At the same time, the combination of TR and GA makes the iteration time consumption of the optimization process less than other traditional algorithms without TR, showing its potential HIFU in clinical scenarios.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Acústica , Algoritmos , Encéfalo/diagnóstico por imagem , Humanos , Análise Espectral
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 1919-1922, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018377

RESUMO

Photoacoustic imaging which combines high contrast of optical imaging and high resolution of ultrasound imaging, can provide functional information, potentially playing a crucial role in the study of breast cancer diagnostics. However, open source dataset for PA imaging research is insufficient on account of lacking clinical data. To tackle this problem, we propose a method to automatically generate breast numerical model for photoacoustic imaging. The different type of tissues is automatically extracted first by employing deep learning and other methods from mammography. And then the tissues are combined by mathematical set operation to generate a new breast image after being assigned optical and acoustic parameters. Finally, breast numerical model with proper optical and acoustic properties are generated, which are specifically suitable for PA imaging studies, and the experiment results indicate that our method is feasible with high efficiency.


Assuntos
Técnicas Fotoacústicas , Mama/diagnóstico por imagem , Aprendizado Profundo , Humanos , Análise Espectral , Ultrassonografia
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 477-480, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018031

RESUMO

The continuous-wave Doppler radar measures the movement of a chest surface including of cardiac and breathing signals and the body movement. The challenges associated with extracting cardiac information in the presence of respiration and body movement have not been addressed thus far. This paper presents a novel method based on the windowed-singular spectrum analysis (WSSA) for solving this issue. The algorithm consists of two processes: signal decomposition via WSSA followed by the reconstruction of decomposed heartbeat signals through convolution. An experiment was conducted to collect chest signals in 212 people by Doppler radar. In order to confirm the effect of reducing the large noise by the proposed method, we evaluated 136 signals that were considered to contain respiration body movements from the collected signals. When comparing to the performance of a band-pass filter, the proposed analysis achieves improved beat count accuracy. The results indicate its applicability to contactless heartbeat estimation under involving respiration and body movements.


Assuntos
Radar , Processamento de Sinais Assistido por Computador , Frequência Cardíaca , Humanos , Respiração , Análise Espectral
8.
Science ; 369(6508): 1160-1161, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32883846
9.
Nat Commun ; 11(1): 4714, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32948754

RESUMO

The application of forces and torques on the single molecule level has transformed our understanding of the dynamic properties of biomolecules, but rare intermediates have remained difficult to characterize due to limited throughput. Here, we describe a method that provides a 100-fold improvement in the throughput of force spectroscopy measurements with topological control, which enables routine imaging of 50,000 single molecules and a 100 million reaction cycles in parallel. This improvement enables detection of rare events in the life cycle of the cell. As a demonstration, we characterize the supercoiling dynamics and drug-induced DNA break intermediates of topoisomerases. To rapidly quantify distinct classes of dynamic behaviors and rare events, we developed a software platform with an automated feature classification pipeline. The method and software can be readily adapted for studies of a broad range of complex, multistep enzymatic pathways in which rare intermediates have escaped classification due to limited throughput.


Assuntos
DNA/química , Fenômenos Magnéticos , Magnetismo/métodos , Nanotecnologia , Análise Espectral/métodos , Ciprofloxacino/farmacologia , DNA/efeitos dos fármacos , Quebras de DNA/efeitos dos fármacos , Conformação de Ácido Nucleico , Pinças Ópticas , Fenômenos Físicos , Software
10.
Vasc Health Risk Manag ; 16: 331-341, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32982262

RESUMO

Purpose: Physiological tests may aid in diagnosing median arcuate ligament syndrome (MALS). MALS is a symptomatic compression of the celiac artery causing symptoms similar to chronic mesenteric ischemia (CMI) of atherosclerotic etiology. Simultaneous use of visible light spectroscopy (VLS) and laser doppler flowmetry (LDF) during upper endoscopy may detect microcirculatory changes in these patients. Patients and Methods: In a single-center, prospective comparative cohort, 25 patients were evaluated for MALS. Patients with a consensus diagnosis of MALS (n=15) underwent a gastroscopy assisted, transmucosal microcirculatory assessment with LDF and VLS. Results were compared to individuals with normal intestinal circulation (n=38) evaluated with duplex ultrasonography, and to patients with chronic mesenteric ischemia (n=32). Treatment response was evaluated clinically at 1, 3, 6, and 12 months, and with ultrasound, VLS and LDF at three months. Health-related quality of life (QoL) was assessed with Euroqol (EQ-5D-5L), preoperatively, and 12 months postoperatively. Results: Preoperative mean transmucosal oxygen saturation was significantly lower in patients with MALS (SO2 76±6), as compared to healthy individuals (SO2 81±4), p=0.02. An overall significant improvement in SO2 after surgical decompression of the celiac artery was found (SO2 81±3.7, p=0.05). Eleven (92%) patients with clinical improvement after laparoscopic decompression had a definitive diagnosis of MALS. Median follow-up was 18 months (4-24 months). Four of the five dimensions investigated with EQ-5D-5L improved. Conclusion: VLS detected a significantly lower baseline transmucosal SO2 in patients with MALS as compared to control subjects with normal intestinal circulation. An improvement in SO2 after laparoscopic decompression was found, supporting a possible ischemic etiology in our patient population.


Assuntos
Artéria Celíaca/fisiopatologia , Duodeno/irrigação sanguínea , Gastroscopia , Fluxometria por Laser-Doppler , Síndrome do Ligamento Arqueado Mediano/diagnóstico , Microcirculação , Circulação Esplâncnica , Estômago/irrigação sanguínea , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Estudos de Casos e Controles , Descompressão Cirúrgica , Feminino , Humanos , Laparoscopia , Masculino , Síndrome do Ligamento Arqueado Mediano/fisiopatologia , Síndrome do Ligamento Arqueado Mediano/cirurgia , Isquemia Mesentérica/diagnóstico , Isquemia Mesentérica/fisiopatologia , Oclusão Vascular Mesentérica/diagnóstico , Oclusão Vascular Mesentérica/fisiopatologia , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Qualidade de Vida , Recuperação de Função Fisiológica , Análise Espectral , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
11.
Nan Fang Yi Ke Da Xue Xue Bao ; 40(6): 843-849, 2020 Jun 30.
Artigo em Chinês | MEDLINE | ID: mdl-32895202

RESUMO

OBJECTIVE: To develop a fast, sensitive and cost-effective method based on resonance light scattering (RLS) for characterization of protein solubility to facilitate detection of changes in solubility of mutant proteins. METHODS: We examined the response curve of RLS intensities to the protein concentrations in synchronous scanning mode. The curve intersection points were searched to predict the maximal concentrations of the protein in dispersion state, which defined the solubility of the protein in this given state. Bovine serum albumin (BSA, 0-50 g/L) was used as the model to investigate the influences of pH values (6.5, 7.0, and 7.4) and salt concentrations (0.05, 0.10, 0.15, and 0.20 mol/L) on the determined solubility. The solubility of glutathione S-transferase isoenzymes alpha (GSTA, 0-27.0 g/L) and Mµ (GSTM, 0-20.0 g/L) were estimated for comparison. The RLS-based method was used to determine the solubility of uricase (MGU, 0-0.4 g/L) to provide assistance in improving the solubility of its mutants. RESULTS: We identified two intersection points in the RLS response curves of the tested proteins, among which the lower one represented an approximation of the maximal concentration (or the solubility of the protein) in single molecular dispersion, and the higher one the saturated concentration of the protein in multiple molecular aggregation. In HEPES buffer, the two intersection points of BSA (isoelectric point 4.6) both increased with the increase of pH (6.5-7.4), and their values were ~1.2 g/L and ~33 g/L at pH 7.4, respectively; the latter concentration approached the solubility of commercial BSA in the same buffer at the same pH. The addition of NaCl reduced the values of the two intersection points, and increasing salt ion concentration decreased the values of the lower intersection points. Further characterizations of GSTA and GSTM showed that the low concentration intersection points of the two proteins were ~0.7 g/L and ~0.8 g/L, and their high concentration intersection points were ~10 g/L and ~11 g/L, respectively, both lower than those of BSA, indicating the feasibility of the direct characterization of protein solubility by RLS. The two concentration intersection points of MGU were 0.24 g/L and 0.30 g/L, respectively, and the low concentration intersection point of its selected mutant was increased by 2 times. CONCLUSIONS: RLS allows direct characterization of the solubility of macromolecular proteins. This method, which is simple and sensitive and needs only a small amount of proteins, has a unique advantage for rapid comparison of solubility of low-abundance protein mutants.


Assuntos
Luz , Concentração de Íons de Hidrogênio , Espalhamento de Radiação , Solubilidade , Análise Espectral
12.
Proc Natl Acad Sci U S A ; 117(37): 23158-23164, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32868421

RESUMO

The recently discovered, chlorophyll-f-containing, far-red photosystem II (FR-PSII) supports far-red light photosynthesis. Participation and kinetics of spectrally shifted far-red pigments are directly observable and separated from that of bulk chlorophyll-a We present an ultrafast transient absorption study of FR-PSII, investigating energy transfer and charge separation processes. Results show a rapid subpicosecond energy transfer from chlorophyll-a to the long-wavelength chlorophylls-f/d The data demonstrate the decay of an ∼720-nm negative feature on the picosecond-to-nanosecond timescales, coinciding with charge separation, secondary electron transfer, and stimulated emission decay. An ∼675-nm bleach attributed to the loss of chl-a absorption due to the formation of a cation radical, PD1 +•, is only fully developed in the nanosecond spectra, indicating an unusually delayed formation. A major spectral feature on the nanosecond timescale at 725 nm is attributed to an electrochromic blue shift of a FR-chlorophyll among the reaction center pigments. These time-resolved observations provide direct experimental support for the model of Nürnberg et al. [D. J. Nürnberg et al., Science 360, 1210-1213 (2018)], in which the primary electron donor is a FR-chlorophyll and the secondary donor is chlorophyll-a (PD1 of the central chlorophyll pair). Efficient charge separation also occurs using selective excitation of long-wavelength chlorophylls-f/d, and the localization of the excited state on P720* points to a smaller (entropic) energy loss compared to conventional PSII, where the excited state is shared over all of the chlorin pigments. This has important repercussions on understanding the overall energetics of excitation energy transfer and charge separation reactions in FR-PSII.


Assuntos
Clorofila/metabolismo , Transferência de Energia/fisiologia , Fotossíntese/fisiologia , Complexo de Proteína do Fotossistema II/metabolismo , Transporte de Elétrons/fisiologia , Cinética , Luz , Análise Espectral/métodos
13.
Nat Commun ; 11(1): 4248, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843623

RESUMO

Femtosecond time-resolved crystallography (TRC) on proteins enables resolving the spatial structure of short-lived photocycle intermediates. An open question is whether confinement and lower hydration of the proteins in the crystalline state affect the light-induced structural transformations. Here, we measured the full photocycle dynamics of a signal transduction protein often used as model system in TRC, Photoactive Yellow Protein (PYP), in the crystalline state and compared those to the dynamics in solution, utilizing electronic and vibrational transient absorption measurements from 100 fs over 12 decades in time. We find that the photocycle kinetics and structural dynamics of PYP in the crystalline form deviate from those in solution from the very first steps following photon absorption. This illustrates that ultrafast TRC results cannot be uncritically extrapolated to in vivo function, and that comparative spectroscopic experiments on proteins in crystalline and solution states can help identify structural intermediates under native conditions.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X/métodos , Fotorreceptores Microbianos/química , Fotorreceptores Microbianos/metabolismo , Proteínas de Bactérias/efeitos da radiação , Cinética , Luz , Estrutura Molecular , Processos Fotoquímicos , Fotorreceptores Microbianos/efeitos da radiação , Conformação Proteica , Análise Espectral
14.
Sci Total Environ ; 746: 141162, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32758988

RESUMO

This study focuses on the determination of alkali release from wood and straw pellets during combustion. The aim is to expand the knowledge on the K and Na release behaviour and to adopt chemiluminescence-based sensors for online monitoring of alkali detection which can be applied for the prevention of fouling formation in low quality biomass combustion plants. Flame emission spectrometry (FES) was used for optical detection of chemiluminescence spectra of K and Na using optical bandpass filters mounted on an ICCD (Intensified Charge Coupled Device) camera. FES data were verified by additional experiments with a single particle reactor (SPR) coupled with an inductively coupled plasma mass spectrometer (ICP-MS). Using both techniques, the release profiles of K and Na during a single pellet combustion at 1000 °C were determined and obtained K* and Na* emission intensities directly correlated with the results from the ICP-MS. It was determined that the emission intensity of alkali radicals depends on alkali concentrations in the samples and K and Na radical emission intensities increase with increasing alkali amounts in the samples. The ICP-MS data revealed that the release of K and Na mainly takes place during the stage of devolatilization. During devolatilization, almost all potassium and sodium are released from wood samples, while only 65-90% of K and 74-90% of Na are released from straw samples. Based on the results, the flame emission spectroscopy technique is capable to fully detect released alkali metals in the gas phase during combustion and proves a possibility to use flame emission sensors for monitoring the release of alkali species from biomass during combustion processes.


Assuntos
Potássio , Sódio , Biomassa , Espectrometria de Massas , Análise Espectral
15.
Waste Manag ; 117: 48-57, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32805601

RESUMO

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


Assuntos
Lasers , Plásticos , Análise de Componente Principal , Reciclagem , Análise Espectral
16.
Mar Pollut Bull ; 159: 111475, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32692678

RESUMO

The significant amount of plastic litter in the form of microplastics (size <5 mm) is garnering attention owing to its potential threat to marine life. Reliable, cost- and time-efficient analysis methods for monitoring microplastic abundance globally are still missing. Several studies proposed a fast detection method by binding the solvatochromic dye Nile Red on the surface of microplastics and using fluorescence microscopy for their detection. All the staining approaches reported so far differ in terms of Nile Red concentration, solvents, and staining procedure. Here, we compare the staining protocols published prior to 2019 and propose an optimized staining protocol. Furthermore, we explore the potential of Nile Red staining in combination with photoluminescence spectroscopy to identify the polymer type and to distinguish plastics from non-plastics.


Assuntos
Plásticos , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Microplásticos , Oxazinas , Análise Espectral , Coloração e Rotulagem
17.
Int J Nanomedicine ; 15: 4091-4104, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606666

RESUMO

Introduction: Humans are intentionally exposed to gold nanoparticles (AuNPs) where they are used in variety of biomedical applications as imaging and drug delivery agents as well as diagnostic and therapeutic agents currently in clinic and in a variety of upcoming clinical trials. Consequently, it is critical that we gain a better understanding of how physiochemical properties such as size, shape, and surface chemistry drive cellular uptake and AuNP toxicity in vivo. Understanding and being able to manipulate these physiochemical properties will allow for the production of safer and more efficacious use of AuNPs in biomedical applications. Methods and Materials: Here, AuNPs of three sizes, 5 nm, 10 nm, and 20 nm, were coated with a lipid bilayer composed of sodium oleate, hydrogenated phosphatidylcholine, and hexanethiol. To understand how the physical features of AuNPs influence uptake through cellular membranes, sum frequency generation (SFG) was utilized to assess the interactions of the AuNPs with a biomimetic lipid monolayer composed of a deuterated phospholipid 1.2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC). Results and Discussion: SFG measurements showed that 5 nm and 10 nm AuNPs are able to phase into the lipid monolayer with very little energetic cost, whereas, the 20 nm AuNPs warped the membrane conforming it to the curvature of hybrid lipid-coated AuNPs. Toxicity of the AuNPs were assessed in vivo to determine how AuNP curvature and uptake influence cell health. In contrast, in vivo toxicity tested in embryonic zebrafish showed rapid toxicity of the 5 nm AuNPs, with significant 24 hpf mortality occurring at concentrations ≥20 mg/L, whereas the 10 nm and 20 nm AuNPs showed no significant mortality throughout the five-day experiment. Conclusion: By combining information from membrane models using SFG spectroscopy with in vivo toxicity studies, a better mechanistic understanding of how nanoparticles (NPs) interact with membranes is developed to understand how the physiochemical features of AuNPs drive nanoparticle-membrane interactions, cellular uptake, and toxicity.


Assuntos
Membrana Celular/química , Ouro/toxicidade , Lipídeos/química , Membranas Artificiais , Nanopartículas Metálicas/toxicidade , Tamanho da Partícula , Testes de Toxicidade , Animais , Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Humanos , Espectrofotometria Ultravioleta , Análise Espectral , Peixe-Zebra/embriologia
18.
Ecotoxicol Environ Saf ; 202: 110898, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32652344

RESUMO

Recent research has shown that the complexation of metals-organics plays an important role in atmospheric particulate matter, whose health effects should be taken into account. This work investigates the interactions between catechols (CAs), i.e., 4-nitrocatechol (4NC) and 4-methylcatechol (4MC), and transition metals (i.e., Fe) in the aqueous phase dark reaction. The formation of Fe/CAs complexes and secondary organics products are analyzed by UV-Vis spectroscopy, stopped-flow spectroscopy, high-resolution mass spectrometry and Raman spectroscopy, while the insoluble particulate matter formed from the CAs/Fe mixtures are characterized by the FTIR, X-ray photoelectron spectroscopy (XPS) and thermogravimetric-quadrupole-mass spectrometry (TG-Q-MS). On the basis of the density functional theory (DFT) calculation and experimental results, the possible formation pathways for the complexes of Fe(III) with 4NC (a proxy for organics) are proposed. The Fe/CAs complexes and organics products perhaps have significant sources of light absorption which play an important role in influencing the intensity of atmospheric radiation and particulate phase photochemistry. Besides, the cytotoxicity is tested as a function of concentrations for CAs/Fe mixtures in BEAS-2B cells. Our results show that CAs/Fe mixtures have strong association with cytotoxicity, indicating the mixtures have potential influence to human health.


Assuntos
Catecóis/química , Compostos Férricos/química , Testes de Toxicidade , Atmosfera/química , Catecóis/toxicidade , Células Epiteliais , Compostos Férricos/toxicidade , Humanos , Espectrometria de Massas , Metais , Material Particulado , Análise Espectral , Água/química
19.
Environ Sci Pollut Res Int ; 27(30): 37887-37893, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32617814

RESUMO

The purpose of this study was to determine the contents of 12 metals in obtainable chalk sticks and assess their associated health risk. Chalk stick samples from 16 factories were analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results showed that 12 metals were detectable in white and colored chalks. The contents of Al, Fe, and Mg were in the range of 646.2-3909 µg/g, 408.8-2075.1 µg/g, and 125-6825.7 µg/g, respectively. Additionally, the levels of Cu, Pb, Mn, and Cr were ranked in the order of Cu>Cr>Pb>Mn, while the maximum levels of As, Ni, Cd, and Sn in all samples (9.90, 10.14, 7.27, and 6.08 µg/g, respectively) were relatively lower than those of other metals. Furthermore, the cumulative hazard index (HI) values of all metals and carcinogenic risk (CR) of As (1.12E-4), Ni (1.39E-4), and Cr (1.15E-4) for children were also higher than the threshold value (1.0E-6 to 1.0E-4), suggesting that chalk dust particles may exert adverse effects on children.


Assuntos
Carbonato de Cálcio , Metais Pesados/análise , Criança , Monitoramento Ambiental , Humanos , Medição de Risco , Análise Espectral
20.
Environ Pollut ; 266(Pt 2): 115227, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32721774

RESUMO

For several decades, use of nanoparticles (NP) on a global scale has been generating new potential sources of organism disruption. Recent studies have shown that NP can cause modifications on the biochemical macromolecular composition of microalgae and raised questions on the toxicity of plastic particles, which are widespread in the aquatic environment. Polystyrene (PS) particles are among the most widely used plastics in the world. In our experimentation, a combined approach of infrared spectroscopy and molecular biology (real-time PCR) has been applied in order to better apprehend the consequences of interactions between Chlamydomonas reinhardtii, freshwater microalgae and PS NP. Two references have been used, nitrogen deprivation -a well-documented stressor-, and gold nanoparticles (Au-NP). As regards biochemical composition, our experiments show a differing microalga response, according to the NP to which they have been exposed. Results with infrared spectroscopy and gene expression methods are consistent and illustrate variation among several carbohydrates (galactose…). Furthermore, PS-NP seem to react in the same direction as nitrogen limitation, thereby supporting the hypothesis that PS-NP can induce response mechanisms to environmental changes in microalgae. This study highlighted the interest of combining infrared spectroscopy and gene expression as means of monitoring microalgae response to nanoplastics.


Assuntos
Chlamydomonas reinhardtii , Nanopartículas Metálicas , Microalgas , Nanopartículas , Poluentes Químicos da Água/análise , Ouro , Poliestirenos , Análise Espectral
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