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BACKGROUND: Drones are able to deliver automated external defibrillators in cases of out-of-hospital cardiac arrest (OHCA) but can be deployed for other purposes. Our aim was to evaluate the feasibility of sending live photos to dispatch centres before arrival of other units during time-critical incidents. METHODS: In this retrospective observational study, the regional dispatch centre implemented a new service using five existing AED-drone systems covering an estimated 200000 inhabitants in Sweden. Drones were deployed automatically over a 4-month study period (December 2022-April 2023) in emergency calls involving suspected OHCAs, traffic accidents and fires in buildings. Upon arrival at the scene, an overhead photo was taken and transmitted to the dispatch centre. Feasibility of providing photos in real time, and time delays intervals were examined. RESULTS: Overall, drones were deployed in 59/440 (13%) of all emergency calls: 26/59 (44%) of suspected OHCAs, 20/59 (34%) of traffic accidents, and 13/59 (22%) of fires in buildings. The main reasons for non-deployment were closed airspace and unfavourable weather conditions (68%). Drones arrived safely at the exact location in 58/59 cases (98%). Their overall median response time was 3:49 min, (IQR 3:18-4:26) vs. emergency medical services (EMS), 05:51 (IQR: 04:29-08:04) p-value for time difference between drone and EMS = 0,05. Drones arrived first on scene in 47/52 cases (90%) and the largest median time difference was found in suspected OHCAs 4:10 min, (IQR: 02:57-05:28). The time difference in the 5/52 (10%) cases when EMS arrived first the time difference was 5:18 min (IQR 2:19-7:38), p = NA. Photos were transmitted correctly in all 59 alerts. No adverse events occurred. CONCLUSION: In a newly implemented drone dispatch service, drones were dispatched to 13% of relevant EMS calls. When drones were dispatched, they arrived at scene earlier than EMS services in 90% of cases. Drones were able to relay photos to the dispatch centre in all cases. Although severely affected by closed airspace and weather conditions, this novel method may facilitate additional decision-making information during time-critical incidents.
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Photoemission orbital tomography (POT) from photoelectron momentum maps (PMMs) is a powerful technique that visualizes the shape of the molecular orbitals (MOs) of molecular films. For further utilization of POT, a simple and low-cost method of POT is highly required. Here, we propose a new POT method based on the PhaseLift algorithm (PhaseLift POT). This method utilizes a lifting procedure to convert the PMM, which is a second-order polynomial of MO coefficients, into a first-order polynomial of the lifted MO coefficients and further relaxes the equality constraint for a given PMM. We also established a method to improve the accuracy of phase retrieval from the noisy PMM data by using sparsity for MO coefficients (sparse PhaseLift POT). These methods make it possible to reconstruct the three-dimensional MOs, including phases of the wave function, directly from a single experimental PMM. This method can also precisely determine the adsorption-induced molecular deformations with an accuracy of 0.05 [Å]. Furthermore, the robust sparse PhaseLift POT is robust against unavoidable noise in the experimental PMMs due to the relaxation of the matching condition for a given PMM. Therefore, this will be an innovative tool for POT, especially for analyzing the dynamics of the molecules during the chemical reaction and excitation processes.
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BACKGROUND AND PURPOSE: Accurate differentiation of paragangliomas and schwannomas in the jugular foramen has important clinical implications because treatment strategies may vary but differentiation is not always straightforward with conventional imaging. Our aim was to evaluate the accuracy of both qualitative and quantitative metrics derived from dynamic contrast-enhanced MR imaging using golden-angle radial sparse parallel MR imaging to differentiate paragangliomas and schwannomas in the jugular foramen. MATERIALS AND METHODS: A retrospective study of imaging data was performed on patients (n = 30) undergoing MR imaging for jugular foramen masses with the golden-angle radial sparse parallel MR imaging technique. Imaging data were postprocessed to obtain time-intensity curves and quantitative parameters. Data were normalized to the dural venous sinus for relevant parameters and analyzed for statistical significance using a Student t test. A univariate logistic model was created with a binary output, paraganglioma or schwannoma, using a wash-in rate as a variable. Additionally, lesions were clustered on the basis of the wash-in rate and washout rate using a 3-nearest neighbors method. RESULTS: There were 22 paragangliomas and 8 schwannomas. All paragangliomas demonstrated a type 3 time-intensity curve, and all schwannomas demonstrated a type 1 time-intensity curve. There was a statistically significant difference between paragangliomas and schwannomas when comparing their values for area under the curve, peak enhancement, wash-in rate, and washout rate. A univariate logistic model with a binary output (paraganglioma or schwannoma) using wash-in rate as a variable was able to correctly predict all observed lesions (P < .001). All 30 lesions were classified correctly by using a 3-nearest neighbors method. CONCLUSIONS: Paragangliomas at the jugular foramen can be reliably differentiated from schwannomas using golden-angle radial sparse parallel MR imaging-dynamic contrast-enhanced imaging when imaging characteristics cannot suffice.
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Foramina Yugular , Neurilemoma , Paraganglioma , Medios de Contraste , Humanos , Imagen por Resonancia Magnética , Neurilemoma/diagnóstico por imagen , Paraganglioma/diagnóstico por imagen , Estudios RetrospectivosRESUMEN
We report ^{51}V NMR and inelastic neutron scattering (INS) measurements on a quasi-1D antiferromagnet BaCo_{2}V_{2}O_{8} under transverse field along the [010] direction. The scaling behavior of the spin-lattice relaxation rate above the Néel temperatures unveils a 1D quantum critical point (QCP) at H_{c}^{1D}≈4.7 T, which is masked by the 3D magnetic order. With the aid of accurate analytical analysis and numerical calculations, we show that the zone center INS spectrum at H_{c}^{1D} is precisely described by the pattern of the 1D quantum Ising model in a magnetic field, a class of universality described in terms of the exceptional E_{8} Lie algebra. These excitations are nondiffusive over a certain field range when the system is away from the 1D QCP. Our results provide an unambiguous experimental realization of the massive E_{8} phase in the compound, and open a new experimental route for exploring the dynamics of quantum integrable systems as well as physics beyond integrability.
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BACKGROUND: Dizziness is a relatively common symptom among patients who call for the emergency medical services (EMS). AIM: To identify factors of importance for the early identification of a time-sensitive condition behind the symptom of dizziness among patients assessed by the EMS. METHODS: All patients assessed by the EMS and triaged using Rapid Emergency Triage and Treatment (RETTS) for adults code 11 (=dizziness) in the 660,000 inhabitants in the Municipality of Gothenburg, Sweden, in 2016, were considered for inclusion. The patients were divided into two groups according to the final diagnosis (a time-sensitive condition, yes or no). RESULTS: There were 1536 patients who fulfilled the inclusion criteria, of which 96 (6.2%) had a time-sensitive condition. The majority of these had a stroke/transitory ischaemic attack (TIA). Eight predictors of a time-sensitive condition were identified. Three were associated with a reduced risk: 1) the dizziness was of a rotatory type, 2) the dizziness had a sudden onset and 3) increasing body temperature. Five were associated with an increased risk: 1) sudden onset of headache, 2) a history of head trauma, 3) symptoms of nausea or vomiting, 4) on treatment with anticoagulants and 5) increasing systolic blood pressure. CONCLUSION: Among 1536 patients who were triaged by the EMS for dizziness, 6.2% had a time-sensitive condition. On the arrival of the EMS, eight factors were associated with the risk of having a time-sensitive condition. All these factors were linked to the type of symptoms or to clinical findings on the arrival of the EMS or to the recent clinical history.
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Mareo , Servicios Médicos de Urgencia , Ataque Isquémico Transitorio , Accidente Cerebrovascular , Factores de Tiempo , Adulto , Mareo/diagnóstico , Mareo/epidemiología , Mareo/etiología , Humanos , Ataque Isquémico Transitorio/diagnóstico , Accidente Cerebrovascular/diagnóstico , Suecia , TriajeRESUMEN
Neurodegenerative disorders are caused by progressive neuronal loss, and there is no complete treatment available yet. Neuroinflammation is a common feature across neurodegenerative disorders and implicated in the progression of neurodegeneration. Dysregulated activation of microglia causes neuroinflammation and has been highlighted as a treatment target in therapeutic strategies. Here, we identified novel therapeutic candidate ALGERNON2 (altered generation of neurons 2) and demonstrate that ALGERNON2 suppressed the production of proinflammatory cytokines and rescued neurodegeneration in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease model. ALGERNON2 stabilized cyclinD1/p21 complex, leading to up-regulation of nuclear factor erythroid 2-related factor 2 (Nrf2), which contributes to antioxidative and anti-inflammatory responses. Notably, ALGERNON2 enhanced neuronal survival in other neuroinflammatory conditions such as the transplantation of induced pluripotent stem cell-derived dopaminergic neurons into murine brains. In conclusion, we present that the microglial potentiation of the p21-Nrf2 pathway can contribute to neuronal survival and provide novel therapeutic potential for neuroinflammation-triggered neurodegeneration.
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Microglía , Enfermedades Neurodegenerativas , Animales , Modelos Animales de Enfermedad , Neuronas Dopaminérgicas/metabolismo , Ratones , Ratones Endogámicos C57BL , Microglía/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Enfermedades Neurodegenerativas/etiología , Enfermedades Neurodegenerativas/metabolismo , Enfermedades Neurodegenerativas/terapia , Enfermedades NeuroinflamatoriasRESUMEN
BACKGROUND AND PURPOSE: Conventional imaging frequently shows overlapping features between benign and malignant parotid neoplasms. We investigated dynamic contrast-enhanced MR imaging using golden-angle radial sparse parallel imaging in differentiating parotid neoplasms. MATERIALS AND METHODS: For this retrospective study, 41 consecutive parotid neoplasms were imaged with dynamic contrast-enhanced MR imaging with golden-angle radial sparse parallel imaging using 1-mm in-plane resolution. The temporal resolution was 3.4 seconds for 78.2 seconds and 8.8 seconds for the remaining acquisition. Three readers retrospectively and independently created and classified time-intensity curves as follows: 1) continuous wash-in; 2) rapid wash-in, subsequent plateau; and 3) rapid wash-in with washout. Additionally, time-intensity curve-derived semiquantitative metrics normalized to the ipsilateral common carotid artery were recorded. Diagnostic performance for the prediction of neoplasm type and malignancy was assessed. Subset multivariate analysis (n = 32) combined semiquantitative time-intensity curve metrics with ADC values. RESULTS: Independent time-intensity curve classification of the 41 neoplasms produced moderate-to-substantial interreader agreement (κ = 0.50-0.79). The time-intensity curve classification threshold of ≥2 predicted malignancy with a positive predictive value of 56.0%-66.7%, and a negative predictive value of 92.0%-100%. The time-intensity curve classification threshold of <2 predicted pleomorphic adenoma with a positive predictive value of 87.0%-95.0% and a negative predictive value of 76.0%-95.0%. For all readers, type 2 and 3 curves were associated with malignant neoplasms (P < .001), and type 1 curves, with pleomorphic adenomas (P < .001). Semiquantitative analysis for malignancy prediction yielded an area under the receiver operating characteristic curve of 0.85 (95% CI, 0.73-0.99). Combining time-to-maximum and ADC predicts pleomorphic adenoma better than either metric alone (P < .001). CONCLUSIONS: Golden-angle radial sparse parallel MR imaging allows high spatial and temporal resolution permeability characterization of parotid neoplasms, with a high negative predictive value for malignancy prediction. Combining time-to-maximum and ADC improves pleomorphic adenoma prediction compared with either metric alone.
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Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Magnética/métodos , Neoplasias de la Parótida/diagnóstico por imagen , Neoplasias de la Parótida/patología , Adulto , Anciano , Anciano de 80 o más Años , Medios de Contraste , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neoplasias de la Parótida/clasificación , Estudios RetrospectivosRESUMEN
BACKGROUND: Out-of-hospital cardiac arrest (OHCA) affects some 275,000 individuals in Europe each year. Time from collapse to defibrillation is essential for survival. As emergency medical services (EMS) response times in Sweden have increased, novel methods are needed to facilitate early treatment. Unmanned aerial vehicles (i.e. drones) have potential to deliver automated external defibrillators (AED). The aim of this simulation study was to explore bystanders' experience of a simulated OHCA-situation where a drone delivers an AED and how the situation is affected by having one or two bystanders onsite. METHODS: This explorative simulation study used a mixed methodology describing bystanders' experiences of retrieving an AED delivered by a drone in simulated OHCA situations. Totally eight participants were divided in two groups of bystanders a) alone or b) in pairs and performed CPR on a manikin for 5 minutes after which an AED was delivered by a drone at 50 m from the location. Qualitative data from observations, interviews of participants and video recordings were analysed using content analysis alongside descriptive data on time delays during bystander interaction. RESULTS: Three categories of bystander experiences emerged: 1) technique and preparedness, 2) support through conversation with the dispatcher, and 3) aid and decision-making. The main finding was that retrieval of an AED as delivered by a drone was experienced as safe and feasible for bystanders. None of the participants hesitated to retrieve the AED; instead they experienced it positive, helpful and felt relief upon AED-drone arrival and were able to retrieve and attach the AED to a manikin. Interacting with the AED-drone was perceived as less difficult than performing CPR or handling their own mobile phone during T-CPR. Single bystander simulation introduced a significant hands-off interval when retrieving the AED, a period lasting 94 s (range 75 s-110 s) with one participant compared to 0 s with two participants. CONCLUSION: The study shows that it made good sense for bystanders to interact with a drone in this simulated suspected OHCA. Bystanders experienced delivery of AED as safe and feasible. This has potential implications, and further studies on bystanders' experiences in real cases of OHCA in which a drone delivers an AED are therefore necessary.
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Reanimación Cardiopulmonar/métodos , Toma de Decisiones , Desfibriladores/provisión & distribución , Cardioversión Eléctrica/instrumentación , Servicios Médicos de Urgencia/métodos , Modelos Teóricos , Paro Cardíaco Extrahospitalario/terapia , Anciano , Anciano de 80 o más Años , Recolección de Datos , Femenino , Humanos , Incidencia , Masculino , Maniquíes , Paro Cardíaco Extrahospitalario/epidemiología , Suecia/epidemiología , Grabación en VideoRESUMEN
To manage the equivalent doses for radiation workers, exposure inhomogeneity is an important factor in the decision-making process related to protection measures and additional monitoring. Our previous study proposed the methodology to evaluate the inhomogeneity of exposure quantitatively. In this study, we applied proposed method to five different types of actual exposure situations encountered in the nuclear industry. Two of them were conventionally characterized as homogeneous exposure, and the other three were conventionally characterized as inhomogeneous exposure. The evaluation of homogeneity exposure was conducted using Monte Carlo calculations with two simplified models, which were then verified with phantom experiments. Consequently, all of the evaluations reproduced the experimental results, implying that our proposed method would be applicable for actual work conditions in the nuclear industry. Furthermore, the two presumed homogeneous exposure situations were found to be rather inhomogeneous because of the contribution of positrons and the limited source region. The results also show that the worker's posture has an impact on the inhomogeneity rather than the energy of incident radiation in nuclear works. The investigation also implies that obtaining the information on the most probable posture of the exposed worker, as well as the existence of the weekly penetrating radiation such as ß± ray as a main source of exposure would be the key for more precise estimation.
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Extremidades/efectos de la radiación , Cristalino/efectos de la radiación , Exposición Profesional/análisis , Fantasmas de Imagen , Exposición a la Radiación/análisis , Monitoreo de Radiación/métodos , Protección Radiológica/métodos , Humanos , Método de Montecarlo , Reactores Nucleares , Dosis de RadiaciónRESUMEN
OBJECTIVES: We compare various aspects in the early chain of care among patients with haemorrhagic stroke and ischaemic stroke. MATERIALS & METHODS: The Emergency Medical Services (EMS) and nine emergency hospitals, each with a stroke unit, were included. All patients hospitalised with a first and a final diagnosis of stroke between 15 December 2010 and 15 April 2011 were included. The primary endpoint was the system delay (from call to the EMS until diagnosis). Secondary endpoints were: (i) use of the EMS, (ii) delay from symptom onset until call to the EMS; (iii) priority at the dispatch centre; (iv) priority by the EMS; and (v) suspicion of stroke by the EMS nurse and physician on admission to hospital. RESULTS: Of 1336 patients, 172 (13%) had a haemorrhagic stroke. The delay from call to the EMS until diagnosis was significantly shorter in haemorrhagic stroke. The patient's decision time was significantly shorter in haemorrhagic stroke. The priority level at the dispatch centre did not differ between the two groups, whereas the EMS nurse gave a significantly higher priority to patients with haemorrhage. There was no significant difference between groups with regard to the suspicion of stroke either by the EMS nurse or by the physician on admission to hospital. CONCLUSIONS: Patients with a haemorrhagic stroke differed from other stroke patients with a more frequent and rapid activation of EMS.
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Isquemia Encefálica/diagnóstico , Hemorragias Intracraneales/diagnóstico , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/etiología , Tiempo de Tratamiento/estadística & datos numéricos , Adulto , Anciano , Isquemia Encefálica/complicaciones , Servicios Médicos de Urgencia , Femenino , Humanos , Hemorragias Intracraneales/complicaciones , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Factores de TiempoRESUMEN
Absolute measurement by the 4πß-γ coincidence counting method was conducted by two photomultipliers facing across a plastic scintillator to be focused on ß ray counting efficiency. The detector was held with a through-hole-type NaI(Tl) detector. The results include absolutely determined activity and its uncertainty especially about extrapolation. A comparison between the obtained and known activities showed agreement within their uncertainties.
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Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness (CHARGE) syndrome is a disorder with multiple congenital anomalies seen on imaging. A retrospective review of 10 patients with CHARGE syndrome who underwent MR imaging of the brain as part of a preoperative evaluation for cochlear implantation was conducted. Structural abnormalities of the entire MR imaging of the head were evaluated, including the auditory system, olfactory system, face, skull base, and central nervous system. The most frequent MR imaging findings included dysplasias of the semicircular canals and hypoplasia of the frontal lobe olfactory sulci. Less frequent findings included cleft lip/palate and coloboma. Our study uncovered new findings of a J-shaped sella, dorsal angulation of the clivus, and absent/atrophic parotid glands, not previously described in patients with CHARGE. Our results emphasize the utility of MR imaging in the diagnosis and management of patients with CHARGE syndrome.
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Síndrome CHARGE/diagnóstico por imagen , Síndrome CHARGE/patología , Imagen por Resonancia Magnética/métodos , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Estudios Retrospectivos , Adulto JovenRESUMEN
We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO_{4})_{2}. The reason is an effective lifting of degeneracy of mean-field ground states by a random potential of impurities, which compensates, in the low-temperature limit, the fluctuation contribution to free energy. These results provide a direct experimental confirmation of the fluctuation origin of the ground state in a real frustrated system. The change of the ground state to a least collinear configuration reveals an effective positive biquadratic exchange provided by the structural disorder. On heating, doped samples regain the structure of a pure compound, thus allowing for an investigation of the remarkable competition between thermal and structural disorder.
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The Bose-Einstein condensation is a fascinating phenomenon, which results from quantum statistics for identical particles with an integer spin. Surprising properties, such as superfluidity, vortex quantization or Josephson effect, appear owing to the macroscopic quantum coherence, which spontaneously develops in Bose-Einstein condensates. Realization of Bose-Einstein condensation is not restricted in fluids like liquid helium, a superconducting phase of paired electrons in a metal and laser-cooled dilute alkali atoms. Bosonic quasi-particles like exciton-polariton and magnon in solids-state systems can also undergo Bose-Einstein condensation in certain conditions. Here, we report that the quantum coherence in Bose-Einstein condensate of the magnon quasi particles yields spontaneous electric polarization in the quantum magnet TlCuCl3, leading to remarkable magnetoelectric effect. Very soft ferroelectricity is realized as a consequence of the O(2) symmetry breaking by magnon Bose-Einstein condensation. The finding of this ferroelectricity will open a new window to explore multi-functionality of quantum magnets.
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Phonon transport is an essential property of thermoelectric materials. Although the phonon carries heat, which reduces the thermoelectric efficiency, it contributes positively to the Seebeck coefficient S through the phonon-drag effect, as typified by the high-purity semiconductors, which show fairly large S at cryogenic temperatures. Although such a large S is attractive in terms of Peltier cooling, a clear guiding principle for designing thermoelectric materials enriched by the phonon-drag effect remains to be established. Here we demonstrate that a correlated semiconductor, FeSb2, is a promising thermoelectric material featuring quasi-ballistic phonons dragging d electrons with large effective mass. By changing the sample size within the sub-millimetre order for high-purity single crystals, we succeed in substantially increasing S to as much as -27 mV K(-1) at low temperatures. Our results exemplify a strategy for exploring phonon-drag-based thermoelectric materials, the performance of which can be maximized by combining heavy electrons with ballistic phonons.
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A multicellular organization is a complex resulting from the coordinated migration of cells to form a specific pattern. The directionality of migration is governed by the mechanical and molecular dynamics of factors secreted from the cells. The mechanism underlying pattern formation is too complex to unveil by culture experiments alone. A mathematical model could provide a powerful tool for elucidating the mechanism of pattern formation by computing the molecular dynamics, which are difficult to visualize by culture experiments. However, there tends to be a gap between mathematical models and experimental research due to incongruity between the idealized conditions of the model and the experimental results. This paper presents an in vitro-in silico interface platform for elucidating the logic of multicellular pattern formation. Two-dimensional collective cell pattern formation was developed using normal human bronchial epithelial cells. Then, geometrical control of collective cells followed by feedback iteration was used to bridge the gap between the mathematical model and in vitro experiments. The mechanisms underlying the pattern formation of bronchial epithelial cells were evaluated using a reaction-diffusion model. The results indicated that differences in the diffusion rates of the activator and inhibitor determine the direction of collective cell migration to form a specific pattern.
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Técnicas de Cultivo de Célula , Células Epiteliales/citología , Animales , Bronquios/citología , Recuento de Células , Diferenciación Celular , Movimiento Celular , Células Cultivadas , Colágeno/química , Difusión , Perros , Combinación de Medicamentos , Humanos , Laminina/química , Células de Riñón Canino Madin Darby , Modelos Teóricos , Simulación de Dinámica Molecular , Morfogénesis , Proteoglicanos/química , Análisis Espacio-TemporalRESUMEN
BACKGROUND: The use of grafts from donors after cardiac death (DCD) would greatly contribute to the expansion of the donor organ pool. The objective of this study is to determine the benefits of extracorporeal membrane oxygenation (ECMO) and subnormothermic machine perfusion (MP) with rewarming in a large animal model of DCD liver. METHODS: After cardiac arrest, the abdominal aorta and the inferior vena cava were cannulated and connected to an ECMO circuit. Porcine livers were perfused in situ with ECMO at 22°C for 60 minutes after 60 minutes of cardiac death. Then the livers were perfused for 4 hours by MP as a graft viability test. In group 1, non-in situ ECMO and grafts were preserved hypothermic MP. In group 2, non-in situ ECMO and grafts were preserved subnormothermic rewarming MP. In group 3, we used ECMO and subnormothermic rewarming MP. To assess potential methods and effect, effluent enzymes were measured. Portal vein and hepatic artery pressure during MP were evaluated. RESULTS: Effluent enzyme of AST, alanine aminotransferase and LDH as viability markers were significantly low (aspartate aminotransferase, 2899, 2292, and 972 IU/L; alanine aminotransferase, 134, 140, and 72 IU/L; and lactate dehydrogenase, 4354, 4455, and 1855 IU/L in each group, respectively). Portal vein and hepatic artery pressure during preservation came down smoothly in group 3 compared with group 1. CONCLUSIONS: The combined use of in situ subnormothermic ECMO and machine preservation with rewarming is more essential for the recovery and resuscitating function of DCD liver grafts.
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Criopreservación/métodos , Oxigenación por Membrana Extracorpórea , Trasplante de Hígado , Hígado/irrigación sanguínea , Preservación de Órganos/métodos , Perfusión/métodos , Recolección de Tejidos y Órganos/métodos , Animales , Muerte , Hígado/metabolismo , Masculino , Recalentamiento , Porcinos , Donantes de TejidosRESUMEN
The purpose of the present review is to discuss and display orbital lesions that demonstrate hypo-intense signal on T2-weighted images (T2WI). The physical basis for hypo-intense signal on T2WI produced by various substances is discussed. Orbital lesions that are hypo-intense on T2WI are subsequently reviewed, including a discussion on their composition as well as relevant clinical and imaging clues that may aid in their diagnosis.
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Imagen por Resonancia Magnética/métodos , Enfermedades Orbitales/diagnóstico , Medios de Contraste , HumanosRESUMEN
A simulation technique was developed for the extrapolation technique in 4πß-γ coincidence counting method. Simultaneous emissions of ß and γ rays were calculated using EGS5 code to obtain coincidence counting between both ß and γ channels. The simulated extrapolation curves were compared with experimental data obtained with (134)Cs measurements using a plastic scintillator in the ß channel. The variation of the extrapolation curves with γ-gate configuration was investigated by the simulation technique.