RESUMO
We developed a biomarker-based approach to quantify in-sewer dilution by measuring wastewater quality parameters (ammoniacal-N, orthophosphate, crAssphage). This approach can enhance the environmental management of wastewater treatment works (WWTW) by optimising their operation and providing cost-effective information on the health and behaviour of populations and their interactions with the environment through wastewater-based epidemiology (WBE). Our method relies on site specific baselines calculated for each biomarker. These baselines reflect the sewer conditions without the influence of rainfall-derived inflow and infiltration (RDII). Ammoniacal-N was the best candidate to use as proxy for dilution. We demonstrated that the dilution calculated using biomarkers correlates well with the dilution indicated by measured flow. In some instances, the biomarkers showed much higher dilution than measured flows. These differences were attributed to the loss of flow volume at wastewater treatment works due to the activation of combined sewer overflows (CSOs) and/or storm tanks. Using flow measured directly at the WWTW could therefore result in underestimation of target analyte loads.
Assuntos
Biomarcadores , Águas Residuárias , Águas Residuárias/análise , Águas Residuárias/química , Biomarcadores/análise , Eliminação de Resíduos Líquidos/métodos , Esgotos , Monitoramento Ambiental/métodosRESUMO
The first British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS)-endorsed faecal microbiota transplant (FMT) guidelines were published in 2018. Over the past 5 years, there has been considerable growth in the evidence base (including publication of outcomes from large national FMT registries), necessitating an updated critical review of the literature and a second edition of the BSG/HIS FMT guidelines. These have been produced in accordance with National Institute for Health and Care Excellence-accredited methodology, thus have particular relevance for UK-based clinicians, but are intended to be of pertinence internationally. This second edition of the guidelines have been divided into recommendations, good practice points and recommendations against certain practices. With respect to FMT for Clostridioides difficile infection (CDI), key focus areas centred around timing of administration, increasing clinical experience of encapsulated FMT preparations and optimising donor screening. The latter topic is of particular relevance given the COVID-19 pandemic, and cases of patient morbidity and mortality resulting from FMT-related pathogen transmission. The guidelines also considered emergent literature on the use of FMT in non-CDI settings (including both gastrointestinal and non-gastrointestinal indications), reviewing relevant randomised controlled trials. Recommendations are provided regarding special areas (including compassionate FMT use), and considerations regarding the evolving landscape of FMT and microbiome therapeutics.
Assuntos
Infecções por Clostridium , Transplante de Microbiota Fecal , Transplante de Microbiota Fecal/métodos , Humanos , Infecções por Clostridium/terapia , Reino Unido , Clostridioides difficile , COVID-19/terapia , Recidiva , Gastroenterologia/normas , Gastroenterologia/métodos , SARS-CoV-2 , Sociedades MédicasRESUMO
In supramolecular materials, multiple weak binding groups can act as a single collective unit when confined to a localized volume, thereby producing strong but dynamic bonds between material building blocks. This principle of multivalency provides a versatile means of controlling material assembly, as both the number and the type of supramolecular moieties become design handles to modulate the strength of intermolecular interactions. However, in materials with building blocks significantly larger than individual supramolecular moieties (e.g., polymer or nanoparticle scaffolds), the degree of multivalency is difficult to predict or control, as sufficiently large scaffolds inherently preclude separated supramolecular moieties from interacting. Because molecular models commonly used to examine supramolecular interactions are intrinsically unable to examine any trends or emergent behaviors that arise due to nanoscale scaffold geometry, our understanding of the thermodynamics of these massively multivalent systems remains limited. Here we address this challenge via the coassembly of polymer-grafted nanoparticles and multivalent polymers, systematically examining how multivalent scaffold size, shape, and spacing affect their collective thermodynamics. Investigating the interplay of polymer structure and supramolecular group stoichiometry reveals complicated but rationally describable trends that demonstrate how the supramolecular scaffold design can modulate the strength of multivalent interactions. This approach to self-assembled supramolecular materials thus allows for the manipulation of polymer-nanoparticle composites with controlled thermal stability, nanoparticle organization, and tailored meso- to microscopic structures. The sophisticated control of multivalent thermodynamics through precise modulation of the nanoscale scaffold geometry represents a significant advance in the ability to rationally design complex hierarchically structured materials via self-assembly.
RESUMO
The scarcity of pristine, intact ecosystems limits opportunities to learn about succession and ecosystem evolution under conditions of limited human impact. Finima Nature Park (FNP) has been identified as a possible RAMSAR site. Its protected lake-"FNP Lake" (also known locally as "Bonny Lake")-is an unusual habitat that enables monitoring of aquatic ecological succession in the Niger Delta, where pristine and near-pristine ecosystems are becoming scarce. Macrozoobenthos are one of the best-known bio-monitors of ecological health integrity because they are widespread and long-lasting, with moderate mobility and high diversity, among other valuable characteristics. Monthly data of the community structure of macrozoobenthos and some of the FNP Lake's priority abiotic factors were collected in 2018, which provided a baseline for identifying future water quality changes and succession in the lake. Except for temperature and dissolved oxygen (DO), which were spatially uniform, the physico-chemical parameters varied spatio-temporally. The diversity indices values were low. According to the canonical correspondence abundance (CCA) plot, taxa distributions were influenced mainly by pH, DO, and temperature, which explains the prevalence of oxygen-insensitive species.
Assuntos
Ecossistema , Lagos , Humanos , Monitoramento Ambiental , Qualidade da Água , NígerRESUMO
At an estimated cost of $8 billion annually in the United States, revision surgeries to total joint replacements represent a substantial financial burden to the health care system and a tremendous mental and physical burden on patients and their caretakers. Fixation failures, such as implant loosening, wear, and mechanical instability of the poly(methyl methacrylate) (PMMA) cement, which bonds the implant to the bone, are the main causes of long-term implant failure. Early and accurate diagnosis of cement failure is critical for developing novel therapeutic strategies and reducing the high risk of a misjudged revision. Unfortunately, prevailing imaging modalities, notably plain radiographs, struggle to detect the precursors of implant failure and are often interpreted incorrectly. Our prior work has shown that the modification of PMMA bone cement with low concentrations of conductive fillers makes it piezoresistive and therefore self-sensing. When combined with a conductivity imaging modality such as electrical impedance tomography (EIT), it is possible to monitor load transfer across the PMMA using cost-effective, physiologically benign, non-contact, and real-time electrical measurements. Despite the ability of EIT for monitoring load transfer across self-sensing PMMA bone cement, it is unable to accurately characterize failure mechanisms. Overcoming this challenge is critical to the success of this technology in practice. Therefore, we herein expand upon our previous results by integrating machine learning techniques with EIT for cement condition characterization with the goal of establishing the feasibility of even off-the-shelf machine learning algorithms to address this important problem. We survey a wide variety of different machine learning algorithms for application to this problem, including neural networks on voltage readings of an EIT phantom for tracking the spatial position of a sample, specifying defect orientation within a sample, and classifying defect types, including cracks and delaminations. In addition, we explore the utilization of principal component analysis (PCA) for pre-treating impedance signals in each of these problems. Within the tested algorithms, our results show clear advantages of neural networks, support vector machines, and K-nearest neighbor algorithms for interpreting EIT signals. We also show that PCA is an effective addition to machine learning. These preliminary results demonstrate that the combination of smart materials, EIT, and machine learning may be a powerful instrumentation tool for diagnosing the origin and evolution of mechanical failure in joint replacements.
Assuntos
Cimentos Ósseos , Polimetil Metacrilato , Humanos , Impedância Elétrica , Tomografia Computadorizada por Raios X , Algoritmos , Tomografia/métodosRESUMO
Direct ink writing, a versatile method of 3D and 4D printing, requires the precise placement of a nozzle just above the print surface to prevent fluid instabilities that cause deviations from the prescribed print path. But what if one could harness the instability associated with the spontaneously folding or coiling of a thin stream of viscous fluid, i.e. use the "fluid rope trick" to write specified patterns on a substrate? Here we use Deep Reinforcement Learning to derive control strategies for the motion of the extruding nozzle and thus the fluid patterns that are deposited on the surface. The method proceeds by having a learner (nozzle) repeatedly interact with the environment (a viscous filament simulator), and improves its strategy using the results of this experience. We demonstrate the outcome of the learned control instructions using experiments to manipulate a falling viscous jet and create cursive writing patterns and Pollockian paintings on substrates.
RESUMO
Tactile sensors, or sensors that collect measurements through touch, have versatile applications in a wide range of fields including robotic gripping, intelligent manufacturing, and biomedical technology. Hoping to match the ability of human hands to sense physical changes in objects through touch, engineers have experimented with a variety of materials from soft polymers to hard ceramics, but so far, all have fallen short. A grand challenge for developers of "human-like" bionic tactile sensors is to be able to sense a wide range of strains while maintaining the low profile necessary for compact integration. Here, we developed a low-profile tactile sensor (â¼300 µm in height) based on patterned, vertically aligned carbon nanotubes (PVACNT) that can repetitively sense compressive strains of up to 75%. Upon compression, reversible changes occur in the points of contact between CNTs, producing measurable changes in electrical admittance. By patterning VACNT pillars with different aspect ratios and pitch sizes, we engineered the range and resolution of strain sensing, suggesting that CNT-based tactile sensors can be integrated according to device specifications.
RESUMO
To be effective, the concentration of antibiotic used must exceed the minimum inhibitory concentration (MIC) against infecting organisms at and in the surgical site. Few studies follow antibiotic levels for tissues that are manipulated during surgery. The aim of this work was to develop and validate a novel LC-MS method as well as an efficient extraction technique for the quantification of cefazolin in local tissues and whole blood. This method uses the same efficient extraction method across multiple tissue types affected by orthopedic surgery: blood, fat, synovium, and bone marrow. The ability to quantify cefazolin in these tissues will help identify surgical techniques and antibiotic dosing protocols that better protect patients from infection. The internal standard, 13C2,15N-cefazolin, co-elutes with cefazolin, and was used in calibration curves and tissue extracts as well as for cefazolin recovery and matrix effects. The protocol was rigorously tested, including measurements of reproducibility and calibration curve quality. The recovery of the extraction method ranges from 94% to 113% across all sample types. There is little to no matrix effect on cefazolin signal (98-120%). The developed method was used to determine cefazolin concentrations in tissues of 10 patients undergoing a total knee replacement. Cefazolin blood concentrations were approximately 500 times higher than in adipose, synovium, and bone marrow tissues. This clinical data shows that although the minimum inhibitory concentration is largely surpassed in blood, the concentration of cefazolin in fat, synovium, and bone marrow could be insufficient during a knee replacement. This method of cefazolin quantification will help surgeons optimize antibiotic concentrations in the local tissues during knee replacement surgery and potentially reduce serious post-surgical infections.
Assuntos
Medula Óssea , Cefazolina , Humanos , Reprodutibilidade dos Testes , Infecção da Ferida Cirúrgica/tratamento farmacológico , Antibioticoprofilaxia/métodos , Antibacterianos , Cromatografia Líquida , Espectrometria de MassasRESUMO
Ultraviolet (UV) printing of photopolymers is a widely adopted manufacturing method because of its high resolution and throughput. However, available printable photopolymers are typically thermosets, resulting in challenges in postprocessing and recycling of printed structures. Here, we present a new process called interfacial photopolymerization (IPP) which enables photopolymerization printing of linear chain polymers. In IPP, a polymer film is formed at the interface between two immiscible liquids, one containing a chain-growth monomer and the other containing a photoinitiator. We demonstrate the integration of IPP in a proof-of-concept projection system for printing of polyacrylonitrile (PAN) films and rudimentary multi-layer shapes . IPP shows in-plane and out-of-plane resolutions comparable to conventional photoprinting methods. Cohesive PAN films with number-average molecular weights greater than 15 kg mol-1 are obtained, and to our knowledge this is the first report of photopolymerization printing of PAN. A macrokinetics model of IPP is developed to elucidate the transport and reaction rates involved and evaluate how reaction parameters affect film thickness and print speed. Last, demonstration of IPP in a multilayer scheme suggests its suitabiliy for three-dimensional printing of linear-chain polymers.
RESUMO
BACKGROUND: Centralization of rectal cancer surgery has been associated with high-quality oncologic care. However, several patient, disease and system-related factors can impact where patients receive care. We hypothesized that patients with low rectal tumors would undergo treatment at high-volume centers and would be more likely to receive guideline-based multidisciplinary treatment. METHODS: Adults who underwent proctectomy for stage II/III rectal cancer were included from the Iowa Cancer Registry and supplemented with tumor location data. Multinomial logistic regression was employed to analyze factors associated with receiving care in high-volume hospital, while logistic regression for those associated with ≥ 12 lymph node yield, pre-operative chemoradiation and sphincter-preserving surgery. RESULTS: Of 414 patients, 38%, 39%, and 22% had low, mid, and high rectal cancers, respectively. Thirty-two percent were > 65 years, 38% female, and 68% had stage III tumors. Older age and rural residence, but not tumor location, were associated with surgical treatment in low-volume hospitals. Higher tumor location, high-volume, and NCI-designated hospitals had higher nodal yield (≥ 12). Hospital-volume was not associated with neoadjuvant chemoradiation rates or circumferential resection margin status. Sphincter-sparing surgery was independently associated with high tumor location, female sex, and stage III cancer, but not hospital volume. CONCLUSIONS: Low tumor location was not associated with care in high-volume hospitals. High-volume and NCI-designated hospitals had higher nodal yields, but not significantly higher neoadjuvant chemoradiation, negative circumferential margin, or sphincter preservation rates. Therefore, providing educational/quality improvement support in lower volume centers may be more pragmatic than attempting to centralize rectal cancer care among high-volume centers.
Assuntos
Canal Anal , Neoplasias Retais , Adulto , Humanos , Feminino , Masculino , Canal Anal/cirurgia , Iowa/epidemiologia , Tratamentos com Preservação do Órgão , Neoplasias Retais/cirurgia , Neoplasias Retais/patologia , Hospitais com Alto Volume de Atendimentos , Sistema de Registros , Estudos Retrospectivos , Estadiamento de NeoplasiasRESUMO
PURPOSE: We investigated bacterial propagation through multifilament, monofilament sutures and whether sutures coated with triclosan would exhibit a different phenomenon. METHODS: One centimetre (cm) wide trenches were cut in the middle of Columbia blood Agar plates. We tested a 6 cm length of two Triclosan-coated (PDS plus®, Vicryl plus®) and two uncoated (PDS ®, Vicryl ®) sutures. Each suture was inoculated with a bacterial suspension containing methicillin-sensitive Staphylococcus aureus (MSSA), Escherichia coli (E. coli), Staphylococcus epidermidis, methicillin-resistant Staphylococcus aureus (MRSA) at one end of each suture. The plates were incubated at 36C for 48 h, followed by room temperature for a further 5 days. We established bacterial propagation by observing for any bacterial growth on the Agar on the opposite side of the trench. RESULTS: Bacterial propagation was observed on the opposite side of the trench with both suture types, monofilament PDS and multifilament Vicryl, when tested with the motile bacterium (E. coli). Propagation was not observed on the other side of the trench with the monofilament PDS suture following incubation with MSSA and S. epidermidis, and in 66% of MRSA. With multifilament suture Vicryl, propagation was observed on the other side of the trench in 90% (MSSA), 80% (S. epidermidis), and 100% (MRSA) of plates tested. No bacterial propagation was observed in any of the triclosan-coated sutures (monofilament or multifilament). CONCLUSIONS: Monofilament sutures are associated in vitro with less bacterial propagation along their course when compared to multifilament sutures. Inhibition in both sutures can be further enhanced with a triclosan coating.
Assuntos
Anti-Infecciosos Locais , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Triclosan , Humanos , Triclosan/farmacologia , Anti-Infecciosos Locais/farmacologia , Escherichia coli , Infecção da Ferida Cirúrgica/prevenção & controle , Infecção da Ferida Cirúrgica/microbiologia , Poliglactina 910 , Ágar , Staphylococcus aureus , Staphylococcus epidermidis , Meticilina , SuturasRESUMO
Development of a refractory selective solar absorber (RSSA) is the key to unlock high-temperature solar thermal and thermochemical conversion. The fundamental challenge of RSSA is the lack of design and fabrication guidelines to simultaneously achieve omnidirectional, broadband solar absorption and sharp spectral selectivity at the desired cutoff wavelength. Here, we realize a ruthenium-carbon nanotube (Ru-CNT) nanocomposite RSSA with multiscale nanoparticle-on-nanocavity plasmonic modes. Ru conformally coated on the sidewalls of CNTs enables a spoof surface plasmon polariton mode for spectra selectivity; Ru nanoparticles formed at the tips of CNTs enable a localized surface plasmon resonance mode and plasmon hybridization for omnidirectional broadband solar absorption. The fabricated Ru-CNT RSSA has a total solar absorption (TSA) of 96.1% with sharp spectral cutoff at 2.21 µm. The TSA is maintained at over 90% for an incident angle of 56°. Our findings therefore guide full-spectrum optical and thermal control from visible to the far-infrared.
RESUMO
Hypoxic-ischemic injury is the most common cause of neonatal encephalopathy. T1-weighted punctate white matter lesions have been described in hypoxic-ischemic injury. We have reviewed a healthy volunteer neonatal population to assess the prevalence of punctate white matter lesions in neonates with no clinical signs of hypoxic-ischemic injury. Fifty-two subjects were scanned on a neonatal-specific 3T MR imaging scanner. Twelve patients were excluded due to the lack of T1-weighted imaging, leaving a total of 40 patients (35 term, 5 preterm) assessed in the study. One had a solitary T1-punctate white matter lesion. We concluded that solitary punctate white matter lesions have a low prevalence in healthy neonates.
Assuntos
Encefalopatias , Hipóxia-Isquemia Encefálica , Substância Branca , Recém-Nascido , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Prevalência , Voluntários Saudáveis , Imageamento por Ressonância Magnética/métodos , Encefalopatias/patologia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Hipóxia-Isquemia Encefálica/patologiaRESUMO
In the early days of total joint replacement, implant fracture, material problems and wear presented major problems for the long-term success of the operation. Today, failures directly related to the implant comprise only 2-3% of the reasons for revision surgeries, which is a result of the material and design improvements in combination with the standardization of pre-clinical testing methods and the post-market surveillance required by the legal regulation. Arthroplasty registers are very effective tools to document the long-term clinical performance of implants and implantation techniques such as fixation methods in combination with patient characteristics. Revisions due to implant failure are initially not reflected by the registries due to their small number. Explant analysis including patient, clinical and imaging documentation is crucial to identify failure mechanisms early enough to prevent massive failures detectable in the registries. In the past, early reaction was not always successful, since explant analysis studies have either been performed late or the results did not trigger preventive measures until clinical failures affected a substantial number of patients. The identification of implant-related problems is only possible if all failures are reported and related to the number of implantations. A system that analyses all explants from revisions attributed to implant failure is mandatory to reduce failures, allowing improvement of risk assessment in the regulatory process.
RESUMO
The aim was to evaluate patient satisfaction with virtual care, and identify factors associated with level of satisfaction. Surveys were mailed to all patients who had a phone visit at The Ottawa Hospital Rheumatology division. Patients' satisfaction with various aspects of the phone visits was assessed on a 5-point scale and analyzed according to demographic variables using chi-square and regression analyses. Of 2423 surveys mailed, we received 742 responses (31%). Eighty-nine percent of patients were satisfied overall with the phone visit. Statistically significant less satisfaction was seen in patients who spoke to a resident compared to their rheumatologist (p < 0.001), were not called on time (p < 0.001), had difficulty using a telephone (p < 0.001), needed assistance of a second person (p < 0.01), or had new consultations (versus routine follow-up, p = 0.01), the former 3 factors being significant in a multivariate regression analysis. Rheumatology patients expressed a high level of satisfaction with virtual care; however, areas of improvement were identified. Patients' satisfaction will be important to inform future decisions regarding the sustainability of virtual care. Further research is required to understand the impacts of virtual care on patients' Key Points ⢠Patients in rheumatology practice were satisfied with phone visits and preferred this method to in-person visits during the pandemic. ⢠Speaking directly to the rheumatologist, being phoned on time, and the capability of using the telephone were the major determinants of high patient satisfaction. ⢠Based on the identified factors, further improvement of the quality of and satisfaction with phone visits can be pursued given that virtual care may continue longer, beyond the pandemic.
Assuntos
COVID-19 , Reumatologia , Telemedicina , Humanos , Pacientes Ambulatoriais , Pandemias , Satisfação do Paciente , TelefoneRESUMO
Chlorosulfonic acid and oleum are ideal solvents for enabling the transformation of disordered carbon nanotubes (CNTs) into precise and highly functional morphologies. Currently, processing these solvents using extrusion techniques presents complications due to chemical compatibility, which constrain equipment and substrate material options. Here, we present a novel acid solvent system based on methanesulfonic or p-toluenesulfonic acids with low corrosivity, which form true solutions of CNTs at concentrations as high as 10 g/liter (≈0.7 volume %). The versatility of this solvent system is demonstrated by drop-in application to conventional manufacturing processes such as slot die coating, solution spinning continuous fibers, and 3D printing aerogels. Through continuous slot coating, we achieve state-of-the-art optoelectronic performance (83.6 %T and 14 ohm/sq) at industrially relevant production speeds. This work establishes practical and efficient means for scalable processing of CNT into advanced materials with properties suitable for a wide range of applications.
RESUMO
The year 2020 presented significant challenges to the field of kidney transplantation. After increasing each year since 2015 and reaching the highest annual count to date in 2019, the total number of kidney trans- plants decreased slightly, to 23642, in 2020. The decrease in total kidney transplants was due to a decrease in living donor transplants; the number of deceased donor transplants rose in 2020. The number of patients waiting for a kidney transplant in the United States declined slightly in 2020, driven by a slight drop in the number of new candidates added in 2020 and an increase in patients removed from the waiting list owing to death-important patterns that correlated with the COVID-19 pandemic. The complexities of the pandemic were accompanied by other ongoing challenges. Nationwide, only about a quarter of waitlisted patients receive a deceased donor kidney transplant within 5 years, a proportion that varies dramatically by donation service area, from 14.8% to 73.0%. The nonutilization (discard) rate of recovered organs rose to its highest value, at 21.3%, despite a dramatic decline in the discard of organs from hepatitis C-positive donors. Nonutilization rates remain particularly high for Kidney Donor Profile Index ≥85% kidneys and kidneys from which a biopsy specimen was obtained. Due to pandemic-related disruption of living donation in spring 2020, the number of living donor transplants in 2020 declined below annual counts over the last decade. In this context, only a small proportion of the waiting list receives living donor transplants each year, and racial disparities in living donor transplant access persist. As both graft and patient survival continue to improve incrementally, the total number of living kidney transplant recipients with a functioning graft exceeded 250,000 in 2020. Pediatric transplant numbers seem to have been impacted by the COVID-19 pandemic. The total number of pediatric kidney transplants performed decreased to 715 in 2020, from a peak of 872 in 2009. Despite numerous efforts, living donor kidney transplant remains low among pediatric recipients, with continued racial disparities among recipients. Of concern, the rate of deceased donor transplant among pediatric waitlisted candidates continued to decrease, reaching its lowest point in 2020. While this may be partly explained by the COVID-19 pandemic, close attention to this trend is critically important. Congenital anomalies of the kidney and urinary tract remain the leading cause of kidney disease in the pediatric population. While most pediatric de- ceased donor recipients receive a kidney from a donor with KDPI less than 35%, most pediatric deceased donor recipients had four or more HLA mis- matches. Graft survival continues to improve, with superior survival for living donor recipients versus deceased donor recipients.
Assuntos
COVID-19 , Obtenção de Tecidos e Órgãos , COVID-19/epidemiologia , Criança , Sobrevivência de Enxerto , Humanos , Rim , Doadores Vivos , Pandemias , Sistema de Registros , SARS-CoV-2 , Doadores de Tecidos , Estados Unidos/epidemiologia , Listas de EsperaRESUMO
Additive manufacturing (AM) has gained significant attention due to its ability to drive technological development as a sustainable, flexible, and customizable manufacturing scheme. Among the various AM techniques, direct ink writing (DIW) has emerged as the most versatile 3D printing technique for the broadest range of materials. DIW allows printing of practically any material, as long as the precursor ink can be engineered to demonstrate appropriate rheological behavior. This technique acts as a unique pathway to introduce design freedom, multifunctionality, and stability simultaneously into its printed structures. Here, a comprehensive review of DIW of complex 3D structures from various materials, including polymers, ceramics, glass, cement, graphene, metals, and their combinations through multimaterial printing is presented. The review begins with an overview of the fundamentals of ink rheology, followed by an in-depth discussion of the various methods to tailor the ink for DIW of different classes of materials. Then, the diverse applications of DIW ranging from electronics to food to biomedical industries are discussed. Finally, the current challenges and limitations of this technique are highlighted, followed by its prospects as a guideline toward possible futuristic innovations.
RESUMO
Molecularly organized nanocomposites of polymers and carbon nanotubes (CNTs) have great promise as high-performance materials; in particular, conformal deposition of polymers can control interfacial properties for mechanical load transfer, electrical or thermal transport, or electro/chemical transduction. However, controllability of polymer-CNT interaction remains a challenge with common processing methods that combine CNTs and polymers in melt or in solution, often leading to nonuniform polymer distribution and CNT aggregation. Here, we demonstrate CNTs within net-shape sheets can be controllably coated with a conformal coating of meta-aramid by simultaneous capillary infiltration and interfacial polymerization. We determine that π-interaction between the polymer and CNTs results in chain alignment parallel to the CNT outer wall. Subsequent nucleation and growth of the precipitated aramid forms a smooth continuous layered sheath around the CNTs. These findings motivate future investigation of mechanical properties of the resulting composites, and adaptation of the in situ polymerization method to other substrates.