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Halide ion exchange seen in metal halide perovskites provide a substantial opportunity to control their halide composition and corresponding optoelectronic properties. Halide ion mixing across colloidal 3D perovskite nanocrystals have been extensively studied while the mixing within colloidal 2D counterparts remain underexplored. In this study, the halide ion exchange kinetics across colloidally stable 2D Ruddlesden-Popper layered bromide (Br) and iodide (I) perovskites using two different spacer ligands such as aromatic phenethylammonium (PEA) versus linear butyammonium (BA) is demonstrated. The halide exchange kinetic rate constant (k), as determined by tracking time-dependent absorbance changes, indicates that Br/I halide mixing in 2D PEA-based perovskites (2.7 × 10-3 min-1 ) occurs at an order of magnitude slower than in 2D BA-based perovskites (3.3 × 10-2 min-1 ). Concentration (≈1 mM to 100 mM) and temperature-dependent (50 to 80 °C) kinetic studies further allow for the determination of activation barrier for halide ion mixing across the 2D layered perovskites with 75.2 ± 4.4 kJ mol-1 (2D PEA) and 57.8 ± 7.8 kJ mol-1 (2D BA), respectively. The activation energy reveals that the type of spacer cations plays a crucial role in controlling the halide ion mobility and halide stability due mainly to the internal ligand chemical interaction within 2D structures.
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The degradation of road pavements due to environmental factors is a pressing issue in infrastructure maintenance, necessitating precise identification of pavement distresses. The pavement condition index (PCI) serves as a critical metric for evaluating pavement conditions, essential for effective budget allocation and performance tracking. Traditional manual PCI assessment methods are limited by labor intensity, subjectivity, and susceptibility to human error. Addressing these challenges, this paper presents a novel, end-to-end automated method for PCI calculation, integrating deep learning and image processing technologies. The first stage employs a deep learning algorithm for accurate detection of pavement cracks, followed by the application of a segmentation-based skeleton algorithm in image processing to estimate crack width precisely. This integrated approach enhances the assessment process, providing a more comprehensive evaluation of pavement integrity. The validation results demonstrate a 95% accuracy in crack detection and 90% accuracy in crack width estimation. Leveraging these results, the automated PCI rating is achieved, aligned with standards, showcasing significant improvements in the efficiency and reliability of PCI evaluations. This method offers advancements in pavement maintenance strategies and potential applications in broader road infrastructure management.
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Lead halide perovskites nanocrystals have emerged as a leading candidate in perovskite solar cells and light-emitting diodes. Given their favorable, tunable optoelectronic properties through modifying the size of nanocrystals, it is imperative to understand and control the growth of lead halide perovskite nanocrystals. However, during the nanocrystal growth into bulk films, the effect of halide bonding on growth kinetics remains elusive. To understand how a chemical bonding of Pb-X (covalency and ionicity) impact on growth of nanocrystals, we have examined two different halide perovskite nanocrystals of CsPbCl3 (more ionic) and CsPbI3 (more covalent) derived from the same parent CsPbBr3 nanocrystals. Tracking the growth of nanocrystals by monitoring the spectral features of bulk peaks (at 445â nm for Cl and at 650â nm for I) enables us to determine the growth activation energy to be 92â kJ/mol (for CsPbCl3 ) versus 71â kJ/mol (for CsPbI3 ). The electronegativity of halides in Pb-X bonds governs the bond strength (150-240â kJ/mol), characteristics of bonding (ionic versus covalent), and growth kinetics and resulting activation energies. A fundamental understanding of Pb-X bonding provides a significant insight into controlling the size of the perovskite nanocrystals with more desired optoelectronic properties.
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A fast-response colorimetric ultraviolet-C (UVC) sensor was demonstrated using a gallium oxide (Ga2O3) photocatalyst with small amounts of triethanolamine (TEOA) in methylene blue (MB) solutions and a conventional RGB photodetector. The color of the MB solution changed upon UVC exposure, which was observed using an in situ RGB photodetector. Thereby, the UVC exposure was numerically quantified as an MB reduction rate with the R value of the photodetector, which was linearly correlated with the measured spectral absorbance using a UV-Vis spectrophotometer. Small amount of TEOA in the MB solution served as a hole scavenger, which resulted in fast MB color changes due to the enhanced charge separation. However, excessive TEOA over 5 wt.% started to block the catalytical active site on the surface of Ga2O3, prohibiting the chemical reaction between the MB molecules and catalytic sites. The proposed colorimetric UVC sensor could monitor the detrimental UVC radiation with high responsivity at a low cost.
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The development of efficient solar energy conversion to augment other renewable energy approaches is one of the grand challenges of our time. Water splitting, or the disproportionation of H2O into energy-dense fuels, H2 and O2, is undoubtedly a promising strategy. Solar water splitting involves the concerted transfer of four electrons and four protons, which requires the synergistic operation of solar light harvesting, charge separation, mass and charge transport, and redox catalysis processes. It is unlikely that individual materials can mediate the entire sequence of charge and mass transport as well as energy conversion processes necessary for photocatalytic water splitting. An alternative approach, emulating the functioning of photosynthetic systems, involves the utilization of hybrid systems wherein different components perform the various functions required for solar water splitting. The design of such hybrid systems requires the multiple components to operate in lockstep with optimal thermodynamic driving forces and interfacial charge transfer kinetics. This Account describes a new class of nanoscale heterostructures comprising M xV2O5 nanowires, where M is a p-block cation with a ( n - 1) d10 ns2 np0 electronic configuration characterized by a stereoactive lone pair of electrons and x is its stoichiometry, interfaced with II-VI semiconductor quantum dots (QDs). Photocatalytic water splitting involves the transfer of excited-state holes from QDs to mid-gap states (derived from the stereoactive lone pairs of p-block cations) of nanowires, hole transport through nanowires, the reduction of protons at a QD-immobilized catalyst, and water oxidation at an anode. The M xV2O5/QD architectures provide a vast design space for evolutionary optimization of function with considerable tunability of composition and structure of the individual components as well as of the interfacial structure, thereby facilitating programmability of absorption spectra, energetic offsets, and charge-transfer reactivity. The available design space spans choice of the p-block cation M, its stoichiometry x, the composition and size of various QDs, and the nature of the nanowire/QD interface. This multivariate parameter space has been navigated by integrating first-principles modeling, diversified synthesis, spectroscopic measurements, and catalytic evaluation to facilitate the rational design of several generations of heterostructures and the systematic improvement of their photocatalytic performance. The electronic structures of the target heterostructures are predicted by DFT calculations in light of the revised lone pair model of stereoactive structural distortions and evaluated by hard X-ray photoelectron spectroscopy such as to systematically tune the interfacial band offsets. Central to this approach is the development of a topochemical "etch-a-sketch" intercalation approach that allows for facile installation of p-block cations in metastable polymorphs of V2O5. The interfacial charge transfer kinetics of M xV2O5/QD heterostructures is further evaluated by transient absorption spectroscopy to measure excited-state charge-transfer dynamics and is found to depend sensitively on interfacial structure and the thermodynamic driving forces in accordance with Marcus theory. The integration of theory and experiment has allowed for the design of viable photocatalytic architectures exemplified by the exceptional catalytic performance of ß-Pb xV2O5/CdX (X= S, Se) architectures, which has subsequently been elaborated to other lone-pair M xV2O5 compounds, demonstrating the effective exploitation of the opportunities for programmability available in the design space.
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PURPOSE OF REVIEW: The field of pediatric mechanical circulatory support has experienced exponential evolution in recent decades. With favorable complication profiles, implantable continuous-flow ventricular assist devices (VADs) have become a standard option in children, as has been seen in the adult counterpart. Nevertheless, there still exists room for further advances, not just for survival, but throughout the whole trajectory of treatment courses. With reviewing the current state of pediatric VAD support, including existing challenges, we aim to highlight the targets clinicians should focus on for further improvement of pediatric VAD support. RECENT FINDINGS: The field of pediatric VAD has been steadily growing, as evidenced by an increasing number of total VAD implants, particularly with continuous-flow VAD. Currently, HeartWare HVAD (Medtronic Inc., Mounds View, MN) is the most widely used continuous-flow VAD in children with excellent performance. However, only half of the children with HVAD are discharged home, which is drastically different from adult patients, suggesting that the pediatric field is still in the process of maturation. Additionally, outcomes of VAD support for complex congenital heart defect, particularly single ventricle physiology, remain suboptimal, despite an increasing number of such patients. SUMMARY: With the ongoing advancement, the field of pediatric VAD support is undergoing a rapid maturation process. This will eventually lead to further paradigm changes, including the use of VAD as permanent therapy.
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Insuficiencia Cardíaca/terapia , Corazón Auxiliar/normas , Enfermedades Vasculares/terapia , Niño , Humanos , Resultado del TratamientoRESUMEN
We synthesized a new class of heterostructures by depositing CdS, CdSe, or CdTe quantum dots (QDs) onto α-V2O5 nanowires (NWs) via either successive ionic layer adsorption and reaction (SILAR) or linker-assisted assembly (LAA). SILAR yielded the highest loadings of QDs per NW, whereas LAA enabled better control over the size and properties of QDs. Soft and hard x-ray photoelectron spectroscopy in conjunction with density functional theory calculations revealed that all α-V2O5/QD heterostructures exhibited Type-II band offset energetics, with a staggered gap where the conduction- and valence-band edges of α-V2O5 NWs lie at lower energies (relative to the vacuum level) than their QD counterparts. Transient absorption spectroscopy measurements revealed that the Type-II energetic offsets promoted the ultrafast (10-12-10-11 s) separation of photogenerated electrons and holes across the NW/QD interface to yield long-lived (10-6 s) charge-separated states. Charge-transfer dynamics and charge-recombination time scales varied subtly with the composition of heterostructures and the nature of the NW/QD interface, with both charge separation and recombination occurring more rapidly within SILAR-derived heterostructures. LAA-derived α-V2O5/CdSe heterostructures promoted the photocatalytic reduction of aqueous protons to H2 with a 20-fold or greater enhancement relative to isolated colloidal CdSe QDs or dispersed α-V2O5 NWs. The separation of photoexcited electrons and holes across the NW/QD interface could thus be exploited in redox photocatalysis. In light of their programmable compositions and properties and their Type-II energetics that drive ultrafast charge separation, the α-V2O5/QD heterostructures are a promising new class of photocatalyst architectures ripe for continued exploration.
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Tackling the complex challenge of harvesting solar energy to generate energy-dense fuels such as hydrogen requires the design of photocatalytic nanoarchitectures interfacing components that synergistically mediate a closely interlinked sequence of light-harvesting, charge separation, charge/mass transport, and catalytic processes. The design of such architectures requires careful consideration of both thermodynamic offsets and interfacial charge-transfer kinetics to ensure long-lived charge carriers that can be delivered at low overpotentials to the appropriate catalytic sites while mitigating parasitic reactions such as photocorrosion. Here we detail the theory-guided design and synthesis of nanowire/quantum dot heterostructures with interfacial electronic structure specifically tailored to promote light-induced charge separation and photocatalytic proton reduction. Topochemical synthesis yields a metastable ß-Sn0.23V2O5 compound exhibiting Sn 5s-derived midgap states ideally positioned to extract photogenerated holes from interfaced CdSe quantum dots. The existence of these midgap states near the upper edge of the valence band (VB) has been confirmed, and ß-Sn0.23V2O5/CdSe heterostructures have been shown to exhibit a 0 eV midgap state-VB offset, which underpins ultrafast subpicosecond hole transfer. The ß-Sn0.23V2O5/CdSe heterostructures are further shown to be viable photocatalytic architectures capable of efficacious hydrogen evolution. The results of this study underscore the criticality of precisely tailoring the electronic structure of semiconductor components to effect rapid charge separation necessary for photocatalysis.
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Recently, quantum dots (QDs) have been successfully developed as efficient color converters for light-emitting diodes (LEDs) display due to excellent optical properties of QDs. Herein, we demonstrate a new approach to form metal oxide layers (or metal oxide coating) on the exterior surface of gradient alloy QDs (the most advanced chemical architecture QDs developed thus far wherein the lattice parameter from the core to shell is changing in a gradient fashion) in order to improve the photochemical stability and photoluminescence efficiency. The resulting CdO-treated QDs are incorporated into polymer matrix films to fabricate a backlight unit as a part of display panel wherein CdO-treated gradient alloy QDs are utilized as color converters upon the blue-LED excitation. The fabricated 9.7 in. iPad 2 tablet liquid crystal display panel exhibited an excellent uniformity in terms of CIE chromaticity, luminance, and bright variation and superb durability test results (maintenance of ca. 110% brightness compared to initial value even after 3 weeks of operation).
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Highly efficient blue-emitting CdSe-derived core/shell gradient alloy quantum dots (CSGA QDs) with photoluminescence quantum yield (PL QY) of ca. 90% have been synthesized through a facile "one-pot" approach. CdSe nuclei are initially formed as core and gradient alloy shells such as CdSexS1-x/ZnSeyS1-y simultaneously encapsulate the preformed CdSe core in an energy-gradient fashion eventually followed by coating with ZnS shells due to the faster precursor reaction kinetics of Cd and Se compared to analog of Zn and S. During the formation of core/shell structure, red-shifting of absorption/emission peaks followed by blue-shifting of analogues were observed due to the intradiffusion of sulfur anion to CdSe luminescent center. In this gradient architecture, interfacial lattice strain can be effectively alleviated, and thus high PL QY (ca. 90%) and enhanced photochemical stability can be achieved. The synthesized blue-emitting gradient alloy QDs with superior optical properties tunable in the range of 450-490 nm can be used for highly efficient blue-emitters and potentially applicable for the fabrication of white-light LEDs.
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The concomitant activation of carbonyl substrates by two Lewis acids has been investigated by using [1,2-(Ph2 MeSb)2 C6 H4 ](2+) ([1](2+) ), an antimony-based bidentate Lewis acid obtained by methylation of the corresponding distibine. Unlike the simple stibonium cation [Ph3 MeSb](+) , dication [1](2+) efficiently catalyzes the hydrosilylation of benzaldehyde under mild conditions. The catalytic activity of this dication is correlated to its ability to doubly activate the carbonyl functionality of the organic substrate. This view is supported by the isolation of [1-µ2 -DMF][OTf]2 , an adduct, in which the DMF oxygen atom bridges the two antimony centers.
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Coxiella burnetii is the causative agent in Q fever, a zoonotic disease. Ocular manifestations of this disease are extremely rare and have been infrequently reported. In this report, we describe a rare case of chorioretinitis in a patient incompletely treated for Q fever. We highlight the unique ocular manifestation with multimodal imaging, and the importance of a thorough history and prompt and correct treatment of the disease with systemic therapy. [Ophthalmic Surg Lasers Imaging Retina 2024;55:412-414.].
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Coriorretinitis , Coxiella burnetii , Infecciones Bacterianas del Ojo , Angiografía con Fluoresceína , Fiebre Q , Tomografía de Coherencia Óptica , Humanos , Coriorretinitis/diagnóstico , Coriorretinitis/microbiología , Fiebre Q/diagnóstico , Fiebre Q/complicaciones , Fiebre Q/microbiología , Fiebre Q/tratamiento farmacológico , Infecciones Bacterianas del Ojo/diagnóstico , Infecciones Bacterianas del Ojo/microbiología , Infecciones Bacterianas del Ojo/tratamiento farmacológico , Tomografía de Coherencia Óptica/métodos , Coxiella burnetii/aislamiento & purificación , Angiografía con Fluoresceína/métodos , Masculino , Antibacterianos/uso terapéutico , Fondo de Ojo , Imagen Multimodal , Persona de Mediana EdadRESUMEN
BACKGROUND: In pediatrics, implantable continuous-flow ventricular assist devices (IC-VAD) are often used as a "temporary" support, bridging children to cardiac transplantation during the same hospital admission. METHODS: We conducted a retrospective review of our consecutive patients undergoing IC-VAD support at a tertiary pediatric heart center between 2008 and 2022. RESULTS: We identified 100 IC-VAD implant encounters: HeartWare HVAD (67; 67%), HeartMate II (17; 17%), and HeartMate 3 (16; 16%). The median (range) age, weight, and body surface area at implantation were 14.1 (3.0-56.5) years, 54.8 (13.3-140) kg, and 1.6 (0.6-2.6) m2, respectively. Cardiomyopathy (58; 58%) was the most common etiology, followed by congenital heart disease (37; 37%, including 13 single ventricle). At 6 months of IC-VAD support, 94 (94%) encounters achieved positive outcomes: ongoing support (59; 59%), transplant (33; 33%), and cardiac recovery (2; 2%). Eighty-two encounters (82%) resulted in home discharge with ongoing VAD support, including 38 (46%, out of 82) requiring readmission and 7 (9%, out of 82) resulting in death. There was a clinically significant decrease in morbidity rates before versus after home discharge: bleeding (1.55 vs 0.06), infection (0.84 vs 0.37), and stroke (0.84 vs 0.15 event per patient-year). Overall, 86 encounters (86%) reached positive end points at the latest follow-up (64 transplant, 15 ongoing support, and 7 recovery). Infection (29%; 4 of 14) was the most common cause of negative outcomes, followed by cerebrovascular accident (21%; 3), and unresolved frailty (21%; 3). The estimated overall survival at 1, 2, and 5 years was 90%, 86%, and 77%, respectively. CONCLUSIONS: This study suggests the feasibility of outpatient management of pediatric IC-VAD support. The ability to offer true long-term support maximizes the potential of IC-VAD support, not limited to a temporary bridging tool for heart transplantation.
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Cardiopatías Congénitas , Insuficiencia Cardíaca , Trasplante de Corazón , Corazón Auxiliar , Accidente Cerebrovascular , Niño , Humanos , Adolescente , Adulto Joven , Adulto , Persona de Mediana Edad , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/terapia , Corazón Auxiliar/efectos adversos , Resultado del Tratamiento , Trasplante de Corazón/efectos adversos , Estudios RetrospectivosRESUMEN
PURPOSE: To determine practice patterns of pediatric ophthalmologists with respect to types of medical conditions cared for and age of patients treated due to limited data regarding pediatric ophthalmologists' scope of practice. METHODS: A survey was sent to 1408 international and United States members of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) membership through the group's internet listserv. Responses were collated and analyzed. RESULTS: Ninety members (6.4%) responded. 89% of respondents confine their practices to pediatric ophthalmology and adult strabismus. The percentages of respondents who provide primary surgical and medical treatment of the following conditions include 68% for ptosis and anterior orbital lesions, 49% for cataracts, 38% for uveitis, 25% for retinopathy of prematurity, 19% for glaucoma, and 7% for retinoblastoma. For conditions other than strabismus, 59% restrict their practice to patients less than 21 years of age. CONCLUSION: Pediatric ophthalmologists provide primary medical and surgical care for children with a wide variety of ocular conditions, including complex disorders. Awareness of this variety of practice might prove beneficial in encouraging residents to consider careers in pediatric ophthalmology. Consequently, fellowship education in pediatric ophthalmology should include exposure to these areas.
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Glaucoma , Oftalmología , Estrabismo , Recién Nacido , Adulto , Humanos , Niño , Estados Unidos , Oftalmología/educación , Alcance de la Práctica , Encuestas y Cuestionarios , Estrabismo/cirugíaRESUMEN
BACKGROUND: Ventricular assist device (VAD) support for failing Glenn circulation represents a unique challenge. METHODS: We conducted a retrospective review of clinical outcomes in patients with VAD support for failing Glenn circulation between 2010 and 2020 at a tertiary pediatric institution. RESULTS: Ten patients were included: INTERMACS profiles were 1 in 3 patients and 2 in 7 patients. The median age, weight, and body surface area were 3.2 years, 13.0 kg, and 0.5 m2, respectively. Seven patients (70%) were implanted with continuous-flow devices and 3 with para-corporeal devices. Nine patients (90%) received heart transplant, with a median support duration of 77 days. Four (67%) out of 6 patients supported with discharge-capable devices were managed as outpatients. Post-transplant survival was 100%, with a median (range) follow up duration of 3.5 (1.8-11.9) years. There were 3 neurologic complications in 3 patients (0.9 events per patient-year); 2 intraoperative events (fatal hypoxia and symptomatic embolic stroke) and 1 postoperative (asymptomatic subarachnoid hemorrhage). Pump thrombosis occurred in one patient (0.3 events per patient-year), requiring pump exchange at day 65. Five patients (50%) received concomitant Fontan completion (fenestrated in 1). The Fontan-upgraded patients (vs Glenn) tended to be larger (median (range): 15.9 (12.6-22.9) vs 9.1 (7.7-22.8) kg), older (4.7 (3.1-6.5) vs 1.1 (0.9-10.1) years) and had a higher PaO2/FiO2 ratio (192 (52-336) vs 76 (59-78) mm Hg) on postoperative day 1. CONCLUSION: Our experience suggests the feasibility of durable VAD support for failing Glenn circulation. Concomitant Fontan completion may be considered in select patients to improve oxygen delivery.
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Insuficiencia Cardíaca , Trasplante de Corazón , Corazón Auxiliar , Niño , Humanos , Preescolar , Corazón Auxiliar/efectos adversos , Pacientes Ambulatorios , Estudios Retrospectivos , Resultado del Tratamiento , Insuficiencia Cardíaca/cirugía , Insuficiencia Cardíaca/etiologíaRESUMEN
Plasma cell dyscrasias are a wide range of severe monoclonal gammopathies caused by pre-malignant or malignant plasma cells that over-secrete an abnormal monoclonal antibody. These disorders are associated with various systemic findings, including ophthalmological disorders. A search of PubMed, EMBASE, Scopus and Cochrane databases was performed in March 2021 to examine evidence pertaining to ocular complications in patients diagnosed with plasma cell dyscrasias. This review outlines the ocular complications associated with smoldering multiple myeloma and monoclonal gammopathy of undetermined significance, plasmacytomas, multiple myeloma, Waldenström's macroglobulinemia, systemic amyloidosis, Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal gammopathy and Skin changes (POEMS) syndrome, and cryoglobulinemia. Although, the pathological mechanisms are not completely elucidated yet, wide-ranging ocular presentations have been identified over the years, evolving both the anterior and posterior segments of the eye. Moreover, the presenting symptoms also help in early diagnosis in asymptomatic patients. Therefore, it is imperative for the treating ophthalmologist and oncologist to maintain a high clinical suspicion for identifying the ophthalmological signs and diagnosing the underlying disease, preventing its progression through efficacious treatment strategies.
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Oftalmopatías , Paraproteinemias , Humanos , Paraproteinemias/complicaciones , Paraproteinemias/diagnóstico , Ojo , Oftalmopatías/diagnóstico , Oftalmopatías/etiología , Resultado del TratamientoRESUMEN
BACKGROUND: There are scarce data describing outcomes of pediatric temporary ventricular assist device support. METHODS: A retrospective single-center study was conducted to review clinical outcomes of all consecutive patients with temporary ventricular assist device between 1996 and 2021. Given the complex clinical course in some patients requiring multiple temporary ventricular assist device runs, outcome analysis was based on "encounters" (hospitalizations with temporary ventricular assist device, regardless of the number of devices used). RESULTS: In total, 126 temporary ventricular assist devices were implanted in 108 patients, resulting in a total of 114 encounters: 70 (61%) extracorporeal centrifugal pumps and 44 (39%) catheter-based axial pumps. The median (range) age and weight at temporary ventricular assist device implant were 10.1 years (1 day to 42.8 years) and 33.6 (2.5-128) kg, respectively. Underlying etiologies of cardiac dysfunction were cardiomyopathy (34, 30%), cardiac transplant graft dysfunction (29, 25%), congenital heart disease (23, 20%; 9 single ventricle), myocarditis (22, 19%), and other (6, 5%). Interagency Registry for Mechanically Assisted Circulatory Support Profile was 1 in 75 (66%) and 2 in 39 (34%). Support configuration was left ventricular assist device (104, including 9 systemic ventricular assist devices), right ventricular assist device (5), and biventricular assist device (5). The median (range) support duration was 6 (1-61) days. Overall, 97 (85%) encounters reached a positive primary end point: bridge-to-recovery (55), bridge-to-bridge (31), and bridge-to-transplant directly with temporary ventricular assist device (11). Seventeen (15%) encounters resulted in death during temporary ventricular assist device support: multiorgan failure (12), stroke (4), and cardiac arrest (1). The 6-month survivals with catheter-based axial pumps and extracorporeal centrifugal pumps were 84% (95% confidence interval, 74-96) and 67% (95% confidence interval, 57-79), respectively (P = .08). The 1- and 5-year survivals of 82 hospital survivors were 90% and 84%, respectively. CONCLUSIONS: This study suggests temporary ventricular assist device support is feasible in children with favorable outcomes.
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Insuficiencia Cardíaca , Corazón Auxiliar , Niño , Humanos , Corazón Auxiliar/efectos adversos , Insuficiencia Cardíaca/terapia , Estudios Retrospectivos , Resultado del Tratamiento , Factores de TiempoRESUMEN
Diverse strategies have been developed to visualize latent fingerprints (LFPs) that are undetectable by the naked eye. Among them, fluorescence-based approaches have emerged as an attractive method for enabling high-resolution LFP imaging. However, the use of fluorescent probes for LFP detection remains challenging due to cumbersome processing, low selectivity, and high background interference. Here, we demonstrate highly efficient, sensitive, and background-free LFP detection with dual-color emission arising from manganese (Mn)-doped lead halide perovskite (CsPb(Cl1-yBry)3) nanocrystals (NCs). The resulting bright, fluorescent, solid-state nanopowder (NP) permits the visualization of LFP ridge structures and the resolution of level 1-3 LFP features. The dual-color emission of the Mn-doped perovskite NP provides a simple, robust, and effective route to overcome background interference, thereby increasing the resolution and sensitivity of the LFP detection. The combination of the high quantum efficiency and dual emission of Mn-doped perovskite NP offers great potential for forensic science.
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Lead halide perovskites nanocrystals have emerged as next-generation materials in the application of photovoltaics and various optoelectronics owing to the controllable optoelectronic properties (achieved through varying the dimensionality and composition of the materials). The design and control to obtain the desirable optoelectronic properties of the halide perovskite nanocrystals, thus, remain paramount importance. The synthesis and stabilization of cesium lead bromide (CsPbBr3) nanoplatelets through ligand-assisted reprecipitation protocol (LARP) can indeed enable the manipulation of the layer thickness over the resulting nanoplatelets. Herein, we have elucidated the role of ligand concentration and chain length effect on the crystal growth and mapped how these parameters affect the layer thickness (and crystal growth kinetics) of the corresponding nanoplatelets. Complex mapping the evolution of the average layer thickness of the CsPbBr3 nanoplatelets provide a detailed perspective of the crystal growth with ligand shell assembly. Transmission electron microscopy (TEM) images directly measurable for the thickness of nanoplatelets along with photoluminescence (PL) emission spectroscopy have been employed to determinate of the thickness of the nanoplatelets exhibiting thickness-dependent optical properties with different layer thickness nanoplatelets.