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1.
Waste Manag ; 122: 64-70, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33486304

RESUMO

In this study, a chemical milling process is developed to convert carbon residues from pyrolyzed waste tires into valuable water-based inkjet printing inks. The residues after waste tire pyrolysis were first sieved to remove ash components and ground into powder (~80 µm). The resulting waste tire carbon blacks (TCB) processed by regular dry or wet milling with the help of compatible solvent can only produce particle sizes around 250 nm. To further reduce particle size under the same mechanical energy, aqueous potassium hydroxide was used in the milling process to leach silica in TCB to create loose and vulnerable structure. Moreover, an ionic surfactant, poly (sodium 4-styrenesulfonate) (PSS), was used to decorate the TCB surface and to inhibit particle aggregation. After chemical milling, the PSS/TCB had a primary particle size around 50 nm and a hydraulic diameter around 110 nm. The PSS/TCB suspension possessed a high zeta potential of -73 mV to stably disperse in water for more than 30 days. To help adhesion of the ink on substrates, the PSS/TCB particles were further mixed with waterborne polyurethane (WPU). The WPU/PSS/TCB ink could be inkjet printed into various black patterns, which showed a higher blackness (jetness value = 342.83) than commercial black inks. Moreover, the printed patterns were water-proof and had a pencil scratch hardness of 4H. In summary, this study provides a guideline to convert waste carbon materials into useful printing supplies, and offers a potential application for waste tire recycling.


Assuntos
Tinta , Fuligem , Carbono , Reciclagem , Água
2.
Sensors (Basel) ; 21(2)2021 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-33445532

RESUMO

Flexible electronics with continuous monitoring ability a extensively preferred in various medical applications. In this work, a flexible pressure sensor based on porous graphene (PG) is proposed for continuous cardiovascular status monitoring. The whole sensor is fabricated in situ by ink printing technology, which grants it the potential for large-scale manufacture. Moreover, to enhance its long-term usage ability, a polyethylene terephthalate/polyethylene vinylacetate (PET/EVA)-laminated film is employed to protect the sensor from unexpected shear forces on the skin surface. The sensor exhibits great sensitivity (53.99/MPa), high resolution (less than 0.3 kPa), wide detecting range (0.3 kPa to 1 MPa), desirable robustness, and excellent repeatability (1000 cycles). With the assistance of the proposed pressure sensor, vital cardiovascular conditions can be accurately monitored, including heart rate, respiration rate, pulse wave velocity, and blood pressure. Compared to other sensors based on self-supporting 2D materials, this sensor can endure more complex environments and has enormous application potential for the medical community.


Assuntos
Sistema Cardiovascular , Grafite/química , Monitorização Fisiológica/instrumentação , Dispositivos Eletrônicos Vestíveis , Adulto , Pressão Sanguínea , Desenho de Equipamento , Frequência Cardíaca , Humanos , Tinta , Monitorização Fisiológica/métodos , Polietilenotereftalatos/química , Polivinil/química , Porosidade , Análise de Onda de Pulso/instrumentação , Análise de Onda de Pulso/métodos , Respiração , Pele , Difração de Raios X
3.
Arkh Patol ; 83(1): 49-52, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33512128

RESUMO

BACKGROUND AND AIM: Histopathological Evaluation of surgical margins of a resected tumour specimen can give an insight about the extent of tumour spread. Errors in proper identification and orientation of resected tumour margins can lead to treatment failure and poor prognosis. Inking of resected margins is the most reliable and safe method. The aim of this study is to systematically review the studies which compares various materials used for inking of surgically resected specimen. MATERIALS AND METHODS: Articles searched from PubMed, Cochrane, Google search, manual search using key words - inking, tissue marking dyes, surgical margin, tumour margin, surgical pathology, grossing, gross specimens and back references of the articles, yielded three articles. Three articles with a total sample size of 1325 and compares properties of India ink, Acrylic colours and Tissue Marking Dyes were considered in this review. RESULTS: Both India ink and acrylic colours are good with respect to the Ease of application, visibility on paraffin wax blocks, Visibility on naked eye examination of slides and Visibility on microscope. Acrylic colours have less drying time than India ink. India ink do not result in contamination of tissue processing fluids, Interference with cellular and nuclear details and penetration in to tissues when compared with acrylic colours. CONCLUSION: India Ink will continue to dominate as the best surgical ink when comparing all the parameters till newer studies are available for acrylic colours or other dyes. Acrylic colours have the potential to be widely used as a tissue marking dyes except for the few disadvantages.


Assuntos
Neoplasias , Patologia Cirúrgica , Corantes , Humanos , Tinta
4.
Sci Total Environ ; 764: 144260, 2021 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-33401040

RESUMO

In this research, a facile and economical route is introduced for the transformation of pharmaceutical waste (i.e., expired medicines) into value-added fluorescent carbon quantum dots (pharmaceutically derived CQDs abbreviated as 'P-CQDs'). The synthesized P-CQDs were identified to have surface functionalities of -OH, C=O, and C=C with an average size of ~2-3 nm and a high quantum yield of 35.3%. The photoluminescence of P-CQDs recorded a maximum optical emission intensity at 2.8 eV (425 nm). The binding of Cu (II) ions by -COOH functionalities on the surface of P-CQDs led to its fluorescence quenching (turn-off) over a wide Cu (II) concentration range of 0.25-50 ppm. The P-CQDs exhibited the detection limit of 0.66 ppm (well below the WHO permissible limit of 2 ppm). The fluorescence intensity of the P-CQDs-Cu (II) complex was recovered from NaHCO3.Hence, their "off-on" behavior was also explored for security ink applications for information encryption and decryption. Moreover, the rich oxygenated groups on the surface of the P-CQDs were utilized for green synthesis of plasmonic Ag@P-CQDs nanostructures, which were also demonstrated to have enhanced potential as bactericidal materials (e.g., against both E. coli and S. aureus). The overall results of this study are demonstrated to help create new and diverse routes for converting expired drugs into value-added nanostructures.


Assuntos
Preparações Farmacêuticas , Pontos Quânticos , Carbono , Escherichia coli , Corantes Fluorescentes , Tinta , Staphylococcus aureus
5.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 5749-5752, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019280

RESUMO

The analysis of the writing gesture has been successfully investigated in the diagnosis of age-related diseases, but the current technologies and methods still do not allow the ecological daily monitoring of handwriting, mostly because they rely on standardized writing protocols. In this study, we first designed and validated a novel electronic ink pen, equipped with motion and writing force sensing, for the ecological daily-life monitoring of handwriting in uncontrolled environments. We used the pen to acquire writing activities from healthy adults, from which we computed useful handwriting and tremor indicators. We evaluated the reliability of our measurements by computing the intraclass correlation coefficients (ICC) and the minimal detectable changes (MDC). Moderate to excellent reliability were obtained for all the handwriting indicators computed in two different writing tasks. MDC values can be used as reference to discriminate a real change in the handwriting parameters from a measurement error in longitudinal studies. These results pave the way towards the use of the pen for daily life handwriting monitoring.


Assuntos
Escrita Manual , Tinta , Reprodutibilidade dos Testes
6.
Environ Sci Pollut Res Int ; 27(36): 45814-45823, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32803575

RESUMO

The efficiency of xylano-pectinolytic enzymes, co-produced by a single microbial strain Bacillus pumilus, was analysed for the recycling of mixed office waste paper through deinking and compared with the alkaline chemical deinking method. Enzymes showed maximum deinking at pH 8.5, pulp consistency of 10%, xylanase-pectinase dose of 12 and 4 IU per gram pulp, respectively, after 120 min of deinking period, and temperature at 50 °C. A chemi-enzymatic approach was employed with xylano-pectinolytic enzymes and various concentrations of deinking chemicals, which showed that enzyme-treated mixed office waste pulp requires only 40% chemicals for deinking, in order to get the almost same level of various handsheets properties, as obtained by the chemical method with 100% chemicals. Similarly, the effluent load of BOD and COD contents was also decreased by 17.90 and 19.75%. This combinational approach of deinking significantly improved the various properties of the handsheets and resulted in gain of 7.5, 9.38, 6.33 and 11.65% in tear factor, burst factor, breaking length and viscosity of the handsheets, while the effective residual ink concentration analysis of deinked handsheets of mixed office waste paper showed deinking efficiency of 22.45%, which revealed the removal of ink particles during enzymatic deinking steps.


Assuntos
Endo-1,4-beta-Xilanases , Tinta , Papel , Poligalacturonase , Reciclagem
7.
Lett Appl Microbiol ; 71(4): 351-358, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32654157

RESUMO

In a 2018 survey, U.S. Food and Drug Administration (FDA) identified microbial contamination in 42 (49%) of 85 unopened tattoo and permanent makeup (PMU) inks purchased from 13 manufacturers in the US between November 2015 and April 2016. To confirm the results of our previous survey, we evaluated the level of microbial contamination in an additional 27 samples from 10 manufacturers from September 2017 to December 2017, including 21 unopened tattoo and PMU inks which were selected based on our previous survey results and 6 ink diluents that were not previously analysed. Aerobic plate count and enrichment culture methods from the FDA's Bacteriological Analytical Manual revealed 11 (52%) out of 21 inks, from six manufacturers, were contaminated with micro-organisms, with contamination levels up to 3·6 × 108  CFU per gram, consistent with our previous survey results. We identified 25 bacterial strains belonging to nine genera and 19 species. Strains of Bacillus sp. (11 strains, 44%) were dominant, followed by Paenibacillus sp. (5 strains, 20%). Clinically relevant strains, such as Kocuria rhizophila and Oligella ureolytica, were also identified, as similar to the findings in our previous survey. No microbial contamination was detected in any of the six ink diluents.


Assuntos
Bactérias/isolamento & purificação , Corantes/química , Tinta , Tatuagem/efeitos adversos , Alcaligenaceae/genética , Alcaligenaceae/isolamento & purificação , Bactérias/classificação , Bactérias/genética , Corantes/efeitos adversos , Contaminação de Medicamentos , Seguimentos , Humanos , Micrococcaceae/genética , Micrococcaceae/isolamento & purificação
8.
Pain Physician ; 23(4): E363-E368, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32709182

RESUMO

BACKGROUND: Ultrasound-guided perineural injections at the lateral femoral cutaneous nerve (LFCN) may confirm the correct diagnosis and provide symptom relief in meralgia paresthetica. Although correct visualization of the nerve is generally described as feasible, failure rates of the procedure may be as high as 30%. OBJECTIVES: This study investigated the spread of injected fluids in ultrasound-guided perineural injections at the LFCN. The aim of the study was to evaluate whether the inguinal ligament impedes the distribution of injected fluids along the course of the LFCN. STUDY DESIGN: We used a descriptive research design. SETTING: Research was conducted at an anatomical research facility. METHODS: In fresh, nonembalmed cadavers, 2 mL of ink were injected with ultrasound-guidance at the LFCN below the inguinal ligament. The course of the nerve was then dissected to show the extent of nerve staining. RESULTS: Spread of the injected ink proximal to the inguinal ligament was found in 67.65% of specimens, while the ink did not pass the inguinal ligament in 32.35%. Concerning proximal spread, specimen body mass index was not of any relevance. LIMITATIONS: This cadaver study is only a simulation of the real clinical setting and does not allow any insight into the efficacy of the injection in living patients. CONCLUSIONS: The inguinal ligament is a barrier in the distribution of injected fluids in about one-third of specimens. This might be a major cause of failure in ultrasound-guided injections. The results from our study are in line with previously published failure rates and our findings might provide the anatomic basis to advance injection techniques. KEY WORDS: Cadaver study; injection; lateral femoral cutaneous nerve; LFCN; meralgia paresthetica; nerve entrapment; sonography; ultrasound.


Assuntos
Nervo Femoral/diagnóstico por imagem , Tinta , Ligamentos/diagnóstico por imagem , Síndromes de Compressão Nervosa/diagnóstico por imagem , Ultrassonografia de Intervenção/métodos , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Nervo Femoral/patologia , Neuropatia Femoral/diagnóstico por imagem , Neuropatia Femoral/patologia , Humanos , Injeções , Ligamentos/patologia , Masculino , Pessoa de Meia-Idade , Síndromes de Compressão Nervosa/patologia , Coxa da Perna/diagnóstico por imagem , Coxa da Perna/inervação
9.
J Occup Health ; 62(1): e12146, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32710690

RESUMO

OBJECTIVES: Along with technological innovations for improving the efficiency of printing, nanoparticles have been added to the surface of toners, and there is concern about the harmful effects of those components. We investigated, through a long-term observation following intratracheal instillation using rats, whether exposure to a toner with external additives can cause tumorigenesis. METHODS: Female Wistar rats were intratracheally instilled with dispersed toner at low (1 mg/rat) and high (2 mg/rat) doses, and the rats were sacrificed at 24 months after exposure, after which we examined pulmonary inflammation, histopathological changes, and DNA damage in the lung. Rats that had deceased before 24 months were dissected at that time as well, to compare tumor development. RESULTS: Although alveolar macrophages with pigment deposition in the alveoli were observed in the 1 and 2 mg exposure groups, no significant lung inflammation/fibrosis or tumor was observed. Since immunostaining with 8-OHdG or γ-H2AX did not show a remarkable positive reaction, it is thought that toner did not cause severe DNA damage to lung tissue. CONCLUSION: These results suggest that toner with external additives may have low toxicity in the lung.


Assuntos
Carcinogênese/induzido quimicamente , Exposição por Inalação/efeitos adversos , Tinta , Pulmão/patologia , Pneumonia/induzido quimicamente , Animais , Líquido da Lavagem Broncoalveolar/química , Feminino , Ratos , Ratos Wistar , Traqueia
10.
Am J Physiol Cell Physiol ; 319(3): C465-C480, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32639873

RESUMO

Bioprinting aims to direct the spatial arrangement in three dimensions of cells, biomaterials, and growth factors. The biofabrication of clinically relevant constructs for the repair or modeling of either diseased or damaged tissues is rapidly advancing, resulting in the ability to three-dimensional (3D) print biomimetic platforms which imitate a large number of tissues in the human body. Primary tissue-specific cells are typically isolated from patients and used for the fabrication of 3D models for drug screening or tissue repair purposes. However, the lack of resilience of these platforms, due to the difficulties in harnessing, processing, and implanting patient-specific cells can limit regeneration ability. The printing of stem cells obviates these hurdles, producing functional in vitro models or implantable constructs. Advancements in biomaterial science are helping the development of inks suitable for the encapsulation and the printing of stem cells, promoting their functional growth and differentiation. This review specifically aims to investigate the most recent studies exploring innovative and functional approaches for the printing of 3D constructs to model disease or repair damaged tissues. Key concepts in tissue physiology are highlighted, reporting stem cell applications in biofabrication. Bioprinting technologies and biomaterial inks are listed and analyzed, including recent advancements in biomaterial design for bioprinting applications, commenting on the influence of biomaterial inks on the encapsulated stem cells. Ultimately, most recent successful efforts and clinical potentials for the manufacturing of functional physiological tissue substitutes are reported here, with a major focus on specific tissues, such as vasculature, heart, lung and airways, liver, bone and muscle.


Assuntos
Bioimpressão , Células-Tronco/citologia , Engenharia Tecidual , Bioimpressão/métodos , Diferenciação Celular/fisiologia , Humanos , Tinta , Técnicas de Cultura de Órgãos/métodos , Engenharia Tecidual/métodos
11.
Biol Bull ; 238(3): 206-213, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32597720

RESUMO

Of the more than 150 ctenophore species, the oceanic ctenophore Eurhamphaea vexilligera is notable for its bright orange-yellow ink, secreted from numerous small vesicles that line its substomodeal comb rows. To date, in situ observations by scuba divers have proved the most fruitful method of observing these animals' natural behavior. We present the results of one such contemporary scuba-based observation of E. vexilligera, conducted in the Gulf Stream waters off the coast of Florida, using high-resolution photography and video. Utilizing underwater camera systems purpose built for filming gelatinous zooplankton, we observed E. vexilligera ink release and swimming behavior in situ. From these data, we describe the timeline and mechanics of E. vexilligera ink release in detail, as well as the animal's different swimming behaviors and resulting ink dispersal patterns. We also describe a rolling swimming behavior, accompanied and possibly facilitated by a characteristic change in overall body shape. These observations provide further insight into the behavioral ecology of this distinctive ctenophore and may serve as the foundation for future kinematic studies.


Assuntos
Ctenóforos , Animais , Comportamento Animal , Florida , Tinta , Natação
12.
Plant Dis ; 104(8): 2242-2251, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32568629

RESUMO

Recently, the incidence of Myrothecium leaf spot, a foliar disease of watermelon, has increased in South Carolina. However, the identity of the fungal species responsible for outbreaks of this disease has not been determined. Sequence data from four partial gene regions were used to conduct Bayesian inference in order to identify 95 isolates of Stachybotriaceae. Isolates were collected in South Carolina between July 2015 and May 2018. In total, six species of Stachybotriaceae were identified on watermelon and two other cucurbits: Albifimbria verrucaria, Gregatothecium humicola, Paramyrothecium foliicola, P. humicola, Xenomyrothecium tongaense, and Xepicula leucotricha. Two species, G. humicola and P. foliicola, were the predominant species found. Within these two species, genetic differences within small spatial scales were detected. Five species (all except Xenomyrothecium tongaense) were tested in experiments to determine their pathogenicity and relative virulence on three hosts grown in rotation in South Carolina. Southern pea plants were less susceptible than watermelon and tomato plants, which were equally susceptible. This constitutes the first reliable report of pathogenicity of any of the five tested species of Stachybotriaceae on these three vegetable crops. Another important finding was that none of the isolates were identified as P. roridum, the species considered to be the only causal agent of Myrothecium leaf spot on cucurbits. We propose the common name "ink spot" for the foliar phase of diseases caused by genera within the family Stachybotriaceae. This name is descriptive and likely to be accepted by growers. To prevent further loss incurred by ink spot, watermelon and tomato crops should be monitored for this disease.


Assuntos
Tinta , Doenças das Plantas , Teorema de Bayes , Variação Genética , South Carolina , Virulência
13.
Environ Sci Pollut Res Int ; 27(29): 36498-36509, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32562224

RESUMO

Lipase enzyme has a critical role in deinking process along with other lignocellulosic enzymes. In this paper, we try to demonstrate the role of lipase in the enzyme cocktail used for enzymatic deinking. For this, we identified a potential lipolytic bacterium, Pseudomonas mendocina ED9 isolated from elephant dung with a molecular weight of 35 kDa. During the Box-Benhken model optimization, a maximum lipase activity of 105.12 U/g, which was 12.36-fold higher than the initial enzyme activity and 1.3-fold higher than the activity obtained during the Plackett Burman design, was achieved. A maximum lipase activity of 105.12 U/g was obtained after optimization. Ammonium sulphate (60%) precipitation resulted in a specific activity of 68.19 U/mg with a 1.4-fold purification and yield of 64%. Lipase from P. mendocina ED9 exhibited a Km of 0.5306 mM and Vmax of 25.0237 µmol/min/mg. A Δ brightness of approximately 14.5% were achieved during the enzymatic deinking using cocktail comprised of cellulase, xylanase and lipase. This reports the significant role and efficacy of lipase in enzyme cocktails for deinking applications. This formulation will reduce the pollution and environmental toxicity of conventional chemical deinking.


Assuntos
Celulase , Pseudomonas mendocina , Concentração de Íons de Hidrogênio , Tinta , Lipase , Papel
14.
J Vis Exp ; (159)2020 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-32421007

RESUMO

During the extrusion-based three-dimensional bioprinting process, liquid-like bioinks with low viscosity can protect cells from membrane damage induced by shear stress and improve the survival of the encapsulated cells. However, rapid gravity-driven cell sedimentation in the reservoir could lead to an inhomogeneous cell distribution in bioprinted structures and therefore hinder the application of liquid-like bioinks. Here, we developed a novel multilayered modified strategy for liquid-like bioinks (e.g., gelatin methacryloyl with low viscosity) to prevent the sedimentation of encapsulated cells. Multiple liquid interfaces were manipulated in the multilayered bioink to provide interfacial retention. Consequently, the cell sedimentation action going across adjacent layers in the multilayered system was retarded in the bioink reservoir. It was found that the interfacial retention was much higher than the sedimental pull of cells, demonstrating a critical role of the interfacial retention in preventing cell sedimentation and promoting a more homogeneous dispersion of cells in the multilayered bioink.


Assuntos
Materiais Biocompatíveis/química , Bioimpressão , Células/metabolismo , Hidrogéis/química , Tinta , Impressão Tridimensional , Animais , Sobrevivência Celular , Fibroínas/química , Gelatina/química , Metacrilatos/química , Camundongos , Células NIH 3T3 , Viscosidade
15.
Nat Commun ; 11(1): 1604, 2020 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-32231216

RESUMO

Conducting polymers are promising material candidates in diverse applications including energy storage, flexible electronics, and bioelectronics. However, the fabrication of conducting polymers has mostly relied on conventional approaches such as ink-jet printing, screen printing, and electron-beam lithography, whose limitations have hampered rapid innovations and broad applications of conducting polymers. Here we introduce a high-performance 3D printable conducting polymer ink based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) for 3D printing of conducting polymers. The resultant superior printability enables facile fabrication of conducting polymers into high resolution and high aspect ratio microstructures, which can be integrated with other materials such as insulating elastomers via multi-material 3D printing. The 3D-printed conducting polymers can also be converted into highly conductive and soft hydrogel microstructures. We further demonstrate fast and streamlined fabrications of various conducting polymer devices, such as a soft neural probe capable of in vivo single-unit recording.


Assuntos
Polímeros/química , Impressão Tridimensional , Elastômeros/química , Condutividade Elétrica , Eletrônica , Hidrogéis/química , Tinta , Poliestirenos/química , Impressão
17.
Carbohydr Polym ; 235: 115970, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32122504

RESUMO

In this study, we provide a photocurable chitosan bioink (CHI-MA), which can be used for the digital light processing (DLP) technology. The CHI-MA precursors were facilely synthesized by grafting chitosan molecular chains with methacryloyl groups. We investigated the effect of parameters, including the concentration and substitution degree (DS) of CHI-MA, on the rheology and the photocuring of bioinks and the mechanical property of photo-crosslinked gels. Using the CHI-MA with a high DS (33.6 %), the curing time to print a 150 µm thick hydrogel layer can be controlled within a reasonable short time period. Additionally, the cytotoxicity test shows that both the photocuring process and the photo-crosslinked hydrogels exhibit an excellent biocompatibility. Through the DLP printing, the CHI-MA bioink can be processed into complex 3D hydrogel structures with high-resolution, high-fidelity and good biocompatibility. It indicates that the photocurable CHI-MA would be a good bioink suitable for the DLP printing.


Assuntos
Técnicas Biossensoriais , Quitosana/química , Tinta , Luz , Impressão Tridimensional , Engenharia Tecidual , Sobrevivência Celular , Células Cultivadas , Células Endoteliais da Veia Umbilical Humana/citologia , Humanos , Hidrogéis/química , Processos Fotoquímicos
18.
Phys Med Biol ; 65(9): 095004, 2020 04 28.
Artigo em Inglês | MEDLINE | ID: mdl-32135522

RESUMO

This study demonstrates remote imaging for in vivo detection of radiation-induced tumor microstructural changes by tracking the diffusive spread of injected intratumor UV excited tattoo ink using Cherenkov-excited luminescence imaging (CELI). Micro-liter quantities of luminescent tattoo ink with UV absorption and visible emission were injected at a depth of 2 mm into mouse tumors prior to receiving a high dose treatment of radiation. X-rays from a clinical linear accelerator were used to excite phosphorescent compounds within the tattoo ink through Cherenkov emission. The in vivo phosphorescence was detected using a time-gated intensified CMOS camera immediately after injection, and then again at varying time points after the ink had broken down with the apoptotic tumor cells. Ex vivo tumors were imaged post-mortem using hyperspectral cryo-fluorescence imaging to quantify necrosis and compared to Cherenkov-excited light imaging of diffusive ink spread measured in vivo. Imaging of untreated control mice showed that ink distributions remained constant after four days with less than 3% diffusive spread measured using full width at 20% max. For all mice, in vivo CELI measurements matched within 12% of the values estimated by the high-resolution ex vivo sliced luminescence imaging of the tumors. The tattoo ink spread in treated mice was found to correlate well with the nonperfusion necrotic core volume (R2 = 0.92) but not well with total tumor volume changes (R2 = 0.34). In vivo and ex vivo findings indicate that the diffusive spread of the injected tattoo ink can be related to radiation-induced necrosis, independent of total tumor volume change. Tracking the diffusive spread of the ink allows for distinguishing between an increase in tumor size due to new cellular growth and an increase in tumor size due to edema. Furthermore, the imaging resolution of CELI allows for in vivo tracking of subtle microenvironmental changes which occur earlier than tumor shrinkage and this offers the potential for novel, minimally invasive radiotherapy response assay without interrupting a singular clinical workflow.


Assuntos
Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/radioterapia , Processamento de Imagem Assistida por Computador/métodos , Tinta , Luminescência , Imagens de Fantasmas , Animais , Proliferação de Células , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Humanos , Camundongos , Camundongos Nus , Células Tumorais Cultivadas , Raios X , Ensaios Antitumorais Modelo de Xenoenxerto
20.
Carbohydr Polym ; 233: 115855, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32059906

RESUMO

The fabrication of magnetic materials typically involves expensive, non-scalable, time-consuming or toxic processes. Here we report a scalable, quick and environmentally-benign fabrication of magnetically active materials through screen printing using mechanically flexible paper having micron-sized pores as substrates. In comparison with traditional multicomponent inks, simple aqueous dispersions comprising solely water-soluble cellulose derivatives and cobalt ferrite nanoparticles are used. Depending on the cellulosic matrix used, inks with viscosities in the 500-2.500 mPa s range were obtained for shear rates of 20-100 s-1. Patterns with line widths from 183 to 642 µm with a maximum deviation of 9 % were fabricated. The largest magnetization saturation obtained of 0.024 emu (or 0.021 emu cm-2) for the hydroxypropyl cellulose-based ink demonstrates enough magnetization for applications in areas such as actuators and sensors. This work provides novel insights towards the processing of renewable, magnetically active and mechanically flexible materials with tailored geometries which use water as the sole solvent.


Assuntos
Celulose/análogos & derivados , Tinta , Nanocompostos/química , Nanopartículas/química , Impressão/métodos , Celulose/química , Cobalto/química , Compostos Férricos/química , Fenômenos Magnéticos , Água/química
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