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Organic semiconductors are a family of pi-conjugated compounds used in many applications, such as displays, bioelectronics, and thermoelectrics. However, their susceptibility to processing-induced contamination is not well understood. Here, it is shown that many organic electronic devices reported so far may have been unintentionally contaminated, thus affecting their performance, water uptake, and thin film properties. Nuclear magnetic resonance spectroscopy is used to detect and quantify contaminants originating from the glovebox atmosphere and common laboratory consumables used during device fabrication. Importantly, this in-depth understanding of the sources of contamination allows the establishment of clean fabrication protocols, and the fabrication of organic field effect transistors (OFETs) with improved performance and stability. This study highlights the role of unintentional contaminants in organic electronic devices, and demonstrates that certain stringent processing conditions need to be met to avoid scientific misinterpretation, ensure device reproducibility, and facilitate performance stability. The experimental procedures and conditions used herein are typical of those used by many groups in the field of solution-processed organic semiconductors. Therefore, the insights gained into the effects of contamination are likely to be broadly applicable to studies, not just of OFETs, but also of other devices based on these materials.
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How to optimise glucose metabolism in the traumatised human brain remains unclear, including whether injured brain can metabolise additional glucose when supplied. We studied the effect of microdialysis-delivered 1,2-13C2 glucose at 4 and 8 mmol/L on brain extracellular chemistry using bedside ISCUSflex, and the fate of the 13C label in the 8 mmol/L group using high-resolution NMR of recovered microdialysates, in 20 patients. Compared with unsupplemented perfusion, 4 mmol/L glucose increased extracellular concentrations of pyruvate (17%, p = 0.04) and lactate (19%, p = 0.01), with a small increase in lactate/pyruvate ratio (5%, p = 0.007). Perfusion with 8 mmol/L glucose did not significantly influence extracellular chemistry measured with ISCUSflex, compared to unsupplemented perfusion. These extracellular chemistry changes appeared influenced by the underlying metabolic states of patients' traumatised brains, and the presence of relative neuroglycopaenia. Despite abundant 13C glucose supplementation, NMR revealed only 16.7% 13C enrichment of recovered extracellular lactate; the majority being glycolytic in origin. Furthermore, no 13C enrichment of TCA cycle-derived extracellular glutamine was detected. These findings indicate that a large proportion of extracellular lactate does not originate from local glucose metabolism, and taken together with our earlier studies, suggest that extracellular lactate is an important transitional step in the brain's production of glutamine.
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Glucose , Glutamina , Humanos , Glucose/metabolismo , Glutamina/metabolismo , Encéfalo/metabolismo , Microdiálise , Ácido Láctico/metabolismo , Ácido Pirúvico/metabolismo , Suplementos NutricionaisRESUMO
Following traumatic brain injury (TBI), raised cerebral lactate/pyruvate ratio (LPR) reflects impaired energy metabolism. Raised LPR correlates with poor outcome and mortality following TBI. We prospectively recruited patients with TBI requiring neurocritical care and multimodal monitoring, and utilised a tiered management protocol targeting LPR. We identified patients with persistent raised LPR despite adequate cerebral glucose and oxygen provision, which we clinically classified as cerebral 'mitochondrial dysfunction' (MD). In patients with TBI and MD, we administered disodium 2,3-13C2 succinate (12 mmol/L) by retrodialysis into the monitored region of the brain. We recovered 13C-labelled metabolites by microdialysis and utilised nuclear magnetic resonance spectroscopy (NMR) for identification and quantification.Of 33 patients with complete monitoring, 73% had MD at some point during monitoring. In 5 patients with multimodality-defined MD, succinate administration resulted in reduced LPR(-12%) and raised brain glucose(+17%). NMR of microdialysates demonstrated that the exogenous 13C-labelled succinate was metabolised intracellularly via the tricarboxylic acid cycle. By targeting LPR using a tiered clinical algorithm incorporating intracranial pressure, brain tissue oxygenation and microdialysis parameters, we identified MD in TBI patients requiring neurointensive care. In these, focal succinate administration improved energy metabolism, evidenced by reduction in LPR. Succinate merits further investigation for TBI therapy.
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Lesões Encefálicas Traumáticas , Encéfalo/metabolismo , Metabolismo Energético/efeitos dos fármacos , Mitocôndrias/metabolismo , Ácido Succínico/administração & dosagem , Adulto , Lesões Encefálicas Traumáticas/tratamento farmacológico , Lesões Encefálicas Traumáticas/metabolismo , Feminino , Humanos , Pressão Intracraniana/efeitos dos fármacos , Ácido Láctico/metabolismo , Masculino , Microdiálise , Pessoa de Meia-Idade , Ressonância Magnética Nuclear Biomolecular , Ácido Pirúvico/metabolismoRESUMO
Chemical purifications are critical processes across many industries, requiring 10-15% of humanity's global energy budget. Coordination cages are able to catch and release guest molecules based upon their size and shape, providing a new technological basis for achieving chemical separation. Here, we show that aqueous solutions of FeII4L6 and CoII4L4 cages can be used as liquid membranes. Selective transport of complex hydrocarbons across these membranes enabled the separation of target compounds from mixtures under ambient conditions. The kinetics of cage-mediated cargo transport are governed by guest binding affinity. Using sequential transport across two consecutive membranes, target compounds were isolated from a mixture in a size-selective fashion. The selectivities of both cages thus enabled a two-stage separation process to isolate a single compound from a mixture of physicochemically similar molecules.
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A bis-urea-functionalized ditopic subcomponent assembled with 2-formylpyridine and FeII , resulting in a dynamic library of metal-organic assemblies: an irregular FeII4 L6 structure and three FeII2 L3 stereoisomers: left- and right-handed helicates and a meso-structure. This library reconfigured in response to the addition of monosaccharide derivatives, which served as guests for specific library members, and the rate of saccharide mutarotation was also enhanced by the library. The (P) enantiomer of the FeII2 L3 helical structure bound ß-D-glucose selectively over α-D-glucose. As a consequence, the library collapsed into the (P)-FeII2 L3 helicate following glucose addition. The α-D-glucose was likewise transformed into the ß-D-anomer during equilibration and binding. Thus, ß-D-glucose and (P)-3 amplified each other in the product mixture, as metal-organic and saccharide libraries geared together into a single equilibrating system.
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A triphasic photocatalytic reactor employing a mesoporous carbon nitride photocatalyst and aerobic O2 was assembled to operate under continuous flow conditions. This reactor design allows for facile downstream processing and reusability in multiple flow cycles. The selective aerobic oxidation of alcohols and amines was chosen to demonstrate the applicability and performance advantage of this flow approach compared to that of conventional batch photochemistry. This precious-metal-free photocatalytic flow system operates under benign reaction conditions (visible light, low pressure, and mild temperature) and will stimulate the exploration of other oxidative reactions in a sustainable, scalable, and affordable manner.
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Metabolic dysfunction is a key pathophysiological process in the acute phase of traumatic brain injury (TBI). Although changes in brain glucose metabolism and extracellular lactate/pyruvate ratio are well known, it was hitherto unknown whether these translate to downstream changes in ATP metabolism and intracellular pH. We have performed the first clinical voxel-based in vivo phosphorus magnetic resonance spectroscopy (31P MRS) in 13 acute-phase major TBI patients versus 10 healthy controls (HCs), at 3T, focusing on eight central 2.5 × 2.5 × 2.5 cm3 voxels per subject. PCr/γATP ratio (a measure of energy status) in TBI patients was significantly higher (median = 1.09) than that of HCs (median = 0.93) (p < 0.0001), due to changes in both PCr and ATP. There was no significant difference in PCr/γATP between TBI patients with favourable and unfavourable outcome. Cerebral intracellular pH of TBI patients was significantly higher (median = 7.04) than that of HCs (median = 7.00) (p = 0.04). Alkalosis was limited to patients with unfavourable outcome (median = 7.07) (p < 0.0001). These changes persisted after excluding voxels with > 5% radiologically visible injury. This is the first clinical demonstration of brain alkalosis and elevated PCr/γATP ratio acutely after major TBI. 31P MRS has potential for non-invasively assessing brain injury in the absence of structural injury, predicting outcome and monitoring therapy response.
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Lesões Encefálicas Traumáticas/metabolismo , Imageamento por Ressonância Magnética/métodos , Fósforo , Trifosfato de Adenosina/metabolismo , Adulto , Alcalose/diagnóstico por imagem , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Estudos de Casos e Controles , Metabolismo Energético , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , PrognósticoRESUMO
Chemical separations technologies are energetically costly; lowering this cost through the development of new molecular separation methods would thus enable significant energy savings. Molecules could, for example, be selectively encapsulated and separated using coordination cages, which can be designed with cavities of tailored sizes and geometries. Before cages can be used to perform industrially relevant separations, however, the experimental and theoretical foundations for this technology must be established. Using hydrophobic and hydrophilic anions as stimuli, we show that cages can reversibly transfer many times between mutually immiscible liquid phases, thus transporting their molecular cargoes over macroscopic distances. Furthermore, when two cages are dissolved together, sequential phase transfer of individual cage species results in the separation of their molecular cargoes. We present a thermodynamic model that describes the transfer profiles of these cages, both individually and in the presence of other cage species. This model provides a new analytical tool to quantify the hydrophobicity of cages.
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A key pathophysiological process and therapeutic target in the critical early post-injury period of traumatic brain injury (TBI) is cell mitochondrial dysfunction; characterised by elevation of brain lactate/pyruvate (L/P) ratio in the absence of hypoxia. We previously showed that succinate can improve brain extracellular chemistry in acute TBI, but it was not clear if this translates to a change in downstream energy metabolism. We studied the effect of microdialysis-delivered succinate on brain energy state (phosphocreatine/ATP ratio (PCr/ATP)) with 31P MRS at 3T, and tissue NADH/NAD+ redox state using microdialysis (L/P ratio) in eight patients with acute major TBI (mean 7 days). Succinate perfusion was associated with increased extracellular pyruvate (+26%, p < 0.0001) and decreased L/P ratio (-13%, p < 0.0001) in patients overall (baseline-vs-supplementation over time), but no clear-cut change in 31P MRS PCr/ATP existed in our cohort (p > 0.4, supplemented-voxel-vs-contralateral voxel). However, the percentage decrease in L/P ratio for each patient following succinate perfusion correlated significantly with their percentage increase in PCr/ATP ratio (Spearman's rank correlation, r = -0.86, p = 0.024). Our findings support the interpretation that L/P ratio is linked to brain energy state, and that succinate may support brain energy metabolism in select TBI patients suffering from mitochondrial dysfunction.
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Lesões Encefálicas Traumáticas/tratamento farmacológico , Lesões Encefálicas Traumáticas/metabolismo , Metabolismo Energético/efeitos dos fármacos , NAD/metabolismo , Fosfatos/metabolismo , Ácido Succínico/farmacologia , Trifosfato de Adenosina/metabolismo , Adulto , Idoso , Encéfalo/metabolismo , Química Encefálica/efeitos dos fármacos , Feminino , Humanos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Ácido Láctico/metabolismo , Espectroscopia de Ressonância Magnética , Masculino , Microdiálise/métodos , Pessoa de Meia-Idade , Oxirredução , Perfusão , Fosfocreatina/metabolismo , Projetos Piloto , Estudos Prospectivos , Ácido Pirúvico/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estatísticas não Paramétricas , Ácido Succínico/administração & dosagem , Ácido Succínico/metabolismo , Resultado do Tratamento , Adulto JovemRESUMO
Metabolic abnormalities occur after traumatic brain injury (TBI). Glucose is conventionally regarded as the major energy substrate, although lactate can also be an energy source. We compared 3-13C lactate metabolism in TBI with "normal" control brain and muscle, measuring 13C-glutamine enrichment to assess tricarboxylic acid (TCA) cycle metabolism. Microdialysis catheters in brains of nine patients with severe TBI, five non-TBI brain surgical patients, and five resting muscle (non-TBI) patients were perfused (24 h in brain, 8 h in muscle) with 8 mmol/L sodium 3-13C lactate. Microdialysate analysis employed ISCUS and nuclear magnetic resonance. In TBI, with 3-13C lactate perfusion, microdialysate glucose concentration increased nonsignificantly (mean +11.9%, p = 0.463), with significant increases (p = 0.028) for lactate (+174%), pyruvate (+35.8%), and lactate/pyruvate ratio (+101.8%). Microdialysate 13C-glutamine fractional enrichments (median, interquartile range) were: for C4 5.1 (0-11.1) % in TBI and 5.7 (4.6-6.8) % in control brain, for C3 0 (0-5.0) % in TBI and 0 (0-0) % in control brain, and for C2 2.9 (0-5.7) % in TBI and 1.8 (0-3.4) % in control brain. 13C-enrichments were not statistically different between TBI and control brain, showing both metabolize 3-13C lactate via TCA cycle, in contrast to muscle. Several patients with TBI exhibited 13C-glutamine enrichment above the non-TBI control range, suggesting lactate oxidative metabolism as a TBI "emergency option."
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Química Encefálica , Lesões Encefálicas Traumáticas/metabolismo , Ácido Láctico/metabolismo , Adolescente , Adulto , Ciclo do Ácido Cítrico , Diálise , Feminino , Glutamina/metabolismo , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxirredução , Adulto JovemRESUMO
To elucidate the role of fluoroethylene carbonate (FEC) as an additive in the standard carbonate-based electrolyte for Li-ion batteries, the solid electrolyte interphase (SEI) formed during electrochemical cycling on silicon anodes was analyzed with a combination of solution and solid-state NMR techniques, including dynamic nuclear polarization. To facilitate characterization via 1D and 2D NMR, we synthesized 13C-enriched FEC, ultimately allowing a detailed structural assignment of the organic SEI. We find that the soluble poly(ethylene oxide)-like linear oligomeric electrolyte breakdown products that are observed after cycling in the standard ethylene carbonate-based electrolyte are suppressed in the presence of 10 vol% FEC additive. FEC is first defluorinated to form soluble vinylene carbonate and vinoxyl species, which react to form both soluble and insoluble branched ethylene-oxide-based polymers. No evidence for branched polymers is observed in the absence of FEC.
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Biogenic alkenes, which are among the most abundant volatile organic compounds in the atmosphere, are readily oxidized by ozone. Characterizing the reactivity and kinetics of the first-generation products of these reactions, carbonyl oxides (often named Criegee intermediates), is essential in defining the oxidation pathways of organic compounds in the atmosphere but is highly challenging due to the short lifetime of these zwitterions. Here, we report the development of a novel online method to quantify atmospherically relevant Criegee intermediates (CIs) in the gas phase by stabilization with spin traps and analysis with proton-transfer reaction mass spectrometry. Ozonolysis of α-pinene has been chosen as a proof-of-principle model system. To determine unambiguously the structure of the spin trap adducts with α-pinene CIs, the reaction was tested in solution, and reaction products were characterized with high-resolution mass spectrometry, electron paramagnetic resonance, and nuclear magnetic resonance spectroscopy. DFT calculations show that addition of the Criegee intermediate to the DMPO spin trap, leading to the formation of a six-membered ring adduct, occurs through a very favorable pathway and that the product is significantly more stable than the reactants, supporting the experimental characterization. A flow tube set up has been used to generate spin trap adducts with α-pinene CIs in the gas phase. We demonstrate that spin trap adducts with α-pinene CIs also form in the gas phase and that they are stable enough to be detected with online mass spectrometry. This new technique offers for the first time a method to characterize highly reactive and atmospherically relevant radical intermediates in situ.
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Alcenos/análise , Sistemas On-Line , Óxidos/análise , Ozônio/química , Prótons , Atmosfera/química , Cinética , Espectrometria de Massas , Teoria QuânticaRESUMO
Following traumatic brain injury, complex cerebral energy perturbations occur. Correlating with unfavourable outcome, high brain extracellular lactate/pyruvate ratio suggests hypoxic metabolism and/or mitochondrial dysfunction. We investigated whether focal administration of succinate, a tricarboxylic acid cycle intermediate interacting directly with the mitochondrial electron transport chain, could improve cerebral metabolism. Microdialysis perfused disodium 2,3-13C2 succinate (12 mmol/L) for 24 h into nine sedated traumatic brain injury patients' brains, with simultaneous microdialysate collection for ISCUS analysis of energy metabolism biomarkers (nine patients) and nuclear magnetic resonance of 13C-labelled metabolites (six patients). Metabolites 2,3-13C2 malate and 2,3-13C2 glutamine indicated tricarboxylic acid cycle metabolism, and 2,3-13C2 lactate suggested tricarboxylic acid cycle spinout of pyruvate (by malic enzyme or phosphoenolpyruvate carboxykinase and pyruvate kinase), then lactate dehydrogenase-mediated conversion to lactate. Versus baseline, succinate perfusion significantly decreased lactate/pyruvate ratio (p = 0.015), mean difference -12%, due to increased pyruvate concentration (+17%); lactate changed little (-3%); concentrations decreased for glutamate (-43%) (p = 0.018) and glucose (-15%) (p = 0.038). Lower lactate/pyruvate ratio suggests better redox status: cytosolic NADH recycled to NAD+ by mitochondrial shuttles (malate-aspartate and/or glycerol 3-phosphate), diminishing lactate dehydrogenase-mediated pyruvate-to-lactate conversion, and lowering glutamate. Glucose decrease suggests improved utilisation. Direct tricarboxylic acid cycle supplementation with 2,3-13C2 succinate improved human traumatic brain injury brain chemistry, indicated by biomarkers and 13C-labelling patterns in metabolites.
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Lesões Encefálicas Traumáticas/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Succinatos/uso terapêutico , Adolescente , Adulto , Biomarcadores/metabolismo , Encéfalo/metabolismo , Química Encefálica/efeitos dos fármacos , Lesões Encefálicas Traumáticas/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Feminino , Humanos , Masculino , Microdiálise , Pessoa de Meia-Idade , Ressonância Magnética Nuclear Biomolecular , Perfusão , Succinatos/administração & dosagem , Índices de Gravidade do Trauma , Adulto JovemRESUMO
Interest in ultrasound education in medical schools has increased dramatically in recent years as reflected in a marked increase in publications on the topic and growing attendance at international meetings on ultrasound education. In 2006, the University of South Carolina School of Medicine introduced an integrated ultrasound curriculum (iUSC) across all years of medical school. That curriculum has evolved significantly over the 9 years. A review of the curriculum is presented, including curricular content, methods of delivery of the content, student assessment, and program assessment. Lessons learned in implementing and expanding an integrated ultrasound curriculum are also presented as are thoughts on future directions of undergraduate ultrasound education. Ultrasound has proven to be a valuable active learning tool that can serve as a platform for integrating the medical student curriculum across many disciplines and clinical settings. It is also well-suited for a competency-based model of medical education. Students learn ultrasound well and have embraced it as an important component of their education and future practice of medicine. An international consensus conference on ultrasound education is recommended to help define the essential elements of ultrasound education globally to ensure ultrasound is taught and ultimately practiced to its full potential. Ultrasound has the potential to fundamentally change how we teach and practice medicine to the benefit of learners and patients across the globe.
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Increased 'anaerobic' glucose metabolism is observed after traumatic brain injury (TBI) attributed to increased glycolysis. An alternative route is the pentose phosphate pathway (PPP), which generates putatively protective and reparative molecules. To compare pathways we employed microdialysis to perfuse 1,2-(13)C2 glucose into the brains of 15 TBI patients and macroscopically normal brain in six patients undergoing surgery for benign tumors, and to simultaneously collect products for nuclear magnetic resonance (NMR) analysis. (13)C enrichment for glycolytic 2,3-(13)C2 lactate was the median 5.4% (interquartile range (IQR) 4.6-7.5%) in TBI brain and 4.2% (2.4-4.4%) in 'normal' brain (P<0.01). The ratio of PPP-derived 3-(13)C lactate to glycolytic 2,3-(13)C2 lactate was median 4.9% (3.6-8.2%) in TBI brain and 6.7% (6.3-8.9%) in 'normal' brain. An inverse relationship was seen for PPP-glycolytic lactate ratio versus PbtO2 (r=-0.5, P=0.04) in TBI brain. Thus, glycolytic lactate production was significantly greater in TBI than 'normal' brain. Several TBI patients exhibited PPP-lactate elevation above the 'normal' range. There was proportionally greater PPP-derived lactate production with decreasing PbtO2. The study raises questions about the roles of the PPP and glycolysis after TBI, and whether they can be manipulated to achieve a better outcome. This study is the first direct comparison of glycolysis and PPP in human brain.
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Lesões Encefálicas/metabolismo , Encéfalo/metabolismo , Glucose/metabolismo , Glicólise , Via de Pentose Fosfato , Adolescente , Adulto , Idoso , Isótopos de Carbono , Estudos de Casos e Controles , Feminino , Humanos , Ácido Láctico/análise , Espectroscopia de Ressonância Magnética , Masculino , Microdiálise , Pessoa de Meia-Idade , Adulto JovemRESUMO
Human brain chemistry is incompletely understood and better methodologies are needed. Traumatic brain injury (TBI) causes metabolic perturbations, one result of which includes increased brain lactate levels. Attention has largely focussed on glycolysis, whereby glucose is converted to pyruvate and lactate, and is proposed to act as an energy source by feeding into neurons' tricarboxylic acid (TCA) cycle, generating ATP. Also reportedly upregulated by TBI is the pentose phosphate pathway (PPP) that does not generate ATP but produces various molecules that are putatively neuroprotective, antioxidant and reparative, in addition to lactate among the end products. We have developed a novel combination of (13)C-labelled cerebral microdialysis both to deliver (13)C-labelled substrates into brains of TBI patients and recover the (13)C-labelled metabolites, with high-resolution (13)C NMR analysis of the microdialysates. This methodology has enabled us to achieve the first direct demonstration in humans that the brain can utilise lactate via the TCA cycle. We are currently using this methodology to make the first direct comparison of glycolysis and the PPP in human brain. In this article, we consider the application of (13)C-labelled cerebral microdialysis for studying brain energy metabolism in patients. We set this methodology within the context of metabolic pathways in the brain, and (13)C research modalities addressing them.
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Lesões Encefálicas/metabolismo , Metabolismo Energético , Metabolômica/métodos , Microdiálise , Biomarcadores/metabolismo , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Humanos , Espectrometria de Massas , Valor Preditivo dos Testes , PrognósticoRESUMO
BACKGROUND: Ultrasound is increasingly recognized as a valuable addition to medical school curriculum. PURPOSE: In this study, we tested the ability of rising second year students to learn and conduct an ultrasound examination of vertical liver span at the point of care. METHODS: Six patients from a GI clinic volunteered to have their liver size measured. Ten students were trained to measure vertical liver span with ultrasound. Four physicians were recruited to measure liver span with standard methods. Student and physician measurements were compared to each other and to a reference ultrasound measurement for accuracy and variability. RESULTS: Compared to the reference, students overestimated liver size an average of 1.5 cm. Physicians underestimated liver size an average of 6.7 cm. Variance in student measurements for each patient was 10% to 17% and among physicians 20% to 50%. CONCLUSION: With limited instruction and clinical experience medical students can obtain liver size measurements with ultrasound that are more accurate and have less variability than those by physicians using physical examination. Given the ease with which students can learn to use ultrasound and the teaching and clinical value of ultrasound, ultrasound should be considered as a standard of medical education in the future.
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Medicina Interna , Fígado/anatomia & histologia , Fígado/diagnóstico por imagem , Exame Físico/normas , Estudantes de Medicina , Educação de Graduação em Medicina , Humanos , Tamanho do Órgão , South Carolina , UltrassonografiaRESUMO
A review of the development and implementation of a 4-year medical student integrated ultrasound curriculum is presented. Multiple teaching and assessment modalities are discussed as well as results from testing and student surveys. Lessons learned while establishing the curriculum are summarized. It is concluded that ultrasound is a well received, valuable teaching tool across all 4 years of medical school, and students learn ultrasound well, and they feel their ultrasound experience enhances their medical education.
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Twenty-one fourth-year medical students were given a brief lecture on ultrasound of the knee and fifteen minutes of supervised ultrasound scanning of three cadavers which had been injected with saline to give varying degrees of knee effusions. Each student was then individually observed and required to scan both knees of a cadaver different from the practice cadavers and identify the patella, the femur, the quadriceps tendon and if a suprapatellar effusion was present, and which knee had the larger effusion. All twenty-one students correctly identified all anatomical structures, suprapatellar effusions, and which knee had the larger effusion. Identifying a knee effusion can be an important clinical finding in diagnosing and managing a patient with knee complaints. Fourth-year medical students can learn to identify knee effusions with ultrasound following a brief introductory lecture and hands-on scanning practice session.