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1.
Acc Chem Res ; 2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-35037453

RESUMO

ConspectusOver the past decade, the impressive development of metal halide perovskites (MHPs) has made them leading candidates for applications in photovoltaics (PVs), X-ray scintillators, and light-emitting diodes (LEDs). Constructing MHP nanocrystals (NCs) with promising optoelectronic properties using a low-cost approach is critical to realizing their commercial potential. Self-assembly and regrowth techniques provide a simple and powerful "bottom-up" platform for controlling the structure, shape, and dimensionality of MHP NCs. The soft ionic nature of MHP NCs, in conjunction with their low formation energy, rapid anion exchange, and ease of ion migration, enables the rearrangement of their overall appearance via self-assembly or regrowth. Because of their low formation energy and highly dynamic surface ligands, MHP NCs have a higher propensity to regrow than conventional hard-lattice NCs. Moreover, their self-assembly and regrowth can be achieved simultaneously. The self-assembly of NCs into close-packed, long-range-ordered mesostructures provides a platform for modulating their electronic properties (e.g., conductivity and carrier mobility). Moreover, assembled MHP NCs exhibit collective properties (e.g., superfluorescence, renormalized emission, longer phase coherence times, and long exciton diffusion lengths) that can translate into dramatic improvements in device performance. Further regrowth into fused MHP nanostructures with the removal of ligand barriers between NCs could facilitate charge carrier transport, eliminate surface point defects, and enhance stability against moisture, light, and electron-beam irradiation. However, the synthesis strategies, diversity and complexity of structures, and optoelectronic applications that emanate from the self-assembly and regrowth of MHPs have not yet received much attention. Consequently, a comprehensive understanding of the design principles of self-assembled and fused MHP nanostructures will fuel further advances in their optoelectronic applications.In this Account, we review the latest developments in the self-assembly and regrowth of MHP NCs. We begin with a survey of the mechanisms, driving forces, and techniques for controlling MHP NC self-assembly. We then explore the phase transition of fused MHP nanostructures at the atomic level, delving into the mechanisms of facet-directed connections and the kinetics of their shape-modulation behavior, which have been elucidated with the aid of high-resolution transmission electron microscopy (HRTEM) and first-principles density functional theory calculations of surface energies. We further outline the applications of assembled and fused nanostructures. Finally, we conclude with a perspective on current challenges and future directions in the field of MHP NCs.

2.
Int J Tuberc Lung Dis ; 26(1): 26-32, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34969425

RESUMO

OBJECTIVE: To investigate the uptake and usage of a WhatsApp-based interactive communication strategy to avert pre-diagnosis loss to follow-up (LTFU) from TB care in a high-incidence setting.METHODS: We enrolled adults (≥18 years) who underwent routine sputum TB testing in two primary healthcare clinics in Khayelitsha, Cape Town, South Africa. The intervention consisted of structured WhatsApp-based reminders (prompts) sent prior to a routine clinic appointment scheduled 2-3 days after the diagnostic visit. Pre-diagnosis LTFU was defined as failure to return for the scheduled appointment and within 10 days.RESULTS: We approached 332 adults with presumptive TB, of whom 103 (31%) were successfully enrolled; 213 (64%) did not own a WhatsApp-compatible phone. Of 103 participants, 74 (72%) actively responded to WhatsApp prompts; 69 (67%) opted to include a close contact in group communication to co-receive reminders. Pre-diagnosis LTFU was low overall (n = 7, 6.8%) and was not associated with failure to respond to WhatsApp prompts.CONCLUSION: In this high-incidence setting, enrolment in a WhatsApp-based communication intervention among adults with presumptive TB was low, mainly due to low availability of WhatsApp-compatible phones. Among participants, we observed high message response rates and low LTFU, suggesting potential for interactive messaging services to support pre-diagnosis TB care.

3.
Artigo em Inglês | MEDLINE | ID: mdl-34882509

RESUMO

INTRODUCTION: More than one million breast augmentation procedures using silicone breast implants (SBI) have been performed worldwide. Adverse events of SBI include local complications such as pain, swelling, redness, infections, capsular contracture, implant rupture and gel-bleed. Furthermore, patients experience systemic symptoms such as chronic fatigue, arthralgias, myalgias, pyrexia, sicca, and cognitive dysfunction. These symptoms received different names such as autoimmune/inflammatory syndrome induced by adjuvants (ASIA) due to silicone incompatibility syndrome and breast implant illness (BII). Because of chronic immune activation, BII/ASIA, allergies, autoimmune diseases, immune deficiencies and finally lymphomas may develop in SBI patients. AREAS COVERED: Causality for SBI-related BII/ASIA is reviewed. To address the role of silicone implants in promoting causality, we utilized the Bradford-Hill criteria, with results highlighted in this article. EXPERT OPINION: We conclude that there is a causal association between SBIs and BII/ASIA. Using data derived from patients with BII/ASIA and from other medically implanted devices, there appears to be clear pathogenic relationship between SBI and BII/ASIA. Breast implants cause characteristic systemic reactions in certain women, leading to symptoms of sufficient severity to warrant device removal. The morbidity suffered is variable. SBI removal resolves the symptoms in most women and removal is the most effective treatment.

4.
Ann R Coll Surg Engl ; 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34807771

RESUMO

Laparoscopic cholecystectomy is the standard of care for the surgical management of symptomatic gallstone disease. Gallstone spillage at laparoscopic cholecystectomy is common, with a reported incidence of 0.2-20%. In the majority of cases there are no complications associated with this spillage, but a series of studies report patients with complications of free peritoneal gallstones. We present a case of migration of gallstone to the lung resulting in an inflammatory mass in the right middle lobe as a complication of spillage at laparoscopic cholecystectomy.

5.
ACS Nano ; 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34723469

RESUMO

Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as one of the most promising light-emitting materials for optoelectronic devices with outstanding performance. However, the facile detachment of surface capping organic ligands from these NCs leads to very poor colloidal stability and durability. This is mainly due to the weak interfacial interactions between the inorganic perovskite core and ligands, high density of surface defect states, and aggregation of NCs. Here, using a combination of time-resolved laser spectroscopy and density functional theory (DFT) calculations, we explored the major impact of surface orientations and terminations for both CsPbBr3 and Cs4PbBr6 NCs not only on the interfacial binding affinities with organic ligands but also on surface defect formation and NC aggregation. By rationalizing that surface trap states are responsible for the decrease in photoluminescence (PL) upon fabrication and purification, we propose a powerful ligand-engineering strategy for eliminating these trap states and preventing the aggregation of CsPbBr3 and Cs4PbBr6 NCs. Interestingly, we find that the surface orientation and dimensionality determine the degree of interfacial interactions between the inorganic perovskite core and ligands and subsequently control the overall PL intensity and NC stability. Our results demonstrate that a treatment of as-synthesized CsPbBr3 NCs consisting of the addition of extra oleylammonium bromide (OAmBr) as a capping ligand, allows the CsPbBr3 NCs to retain their green emission with increased PL intensity and quantum yields and improves colloidal durability. On the other hand, the ultraviolet emissions of Cs4PbBr6 NCs are effectively increased upon addition of extra cesium oleate (CsOL) as the trap states induced by surface cesium ions are largely reduced by the formation of Cs-O bonds. Our work provides a robust and adequate ligand engineering approach to significantly enhance the optical behavior of perovskite NCs with different dimensionalities and various compositions and to achieve more efficient and stable light-harvesting devices.

6.
J Glob Health ; 11: 04065, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34737865

RESUMO

Background: Our previous scoping review revealed limitations and inconsistencies in population surveys of chronic respiratory disease. Informed by this review, we piloted a cross-sectional survey of adults in four South/South-East Asian low-and middle-income countries (LMICs) to assess survey feasibility and identify variables that predicted asthma or chronic obstructive pulmonary disease (COPD). Methods: We administered relevant translations of the BOLD-1 questionnaire with additional questions from ECRHS-II, performed spirometry and arranged specialist clinical review for a sub-group to confirm the diagnosis. Using random sampling, we piloted a community-based survey at five sites in four LMICs and noted any practical barriers to conducting the survey. Three clinicians independently used information from questionnaires, spirometry and specialist reviews, and reached consensus on a clinical diagnosis. We used lasso regression to identify variables that predicted the clinical diagnoses and attempted to develop an algorithm for detecting asthma and COPD. Results: Of 508 participants, 55.9% reported one or more chronic respiratory symptoms. The prevalence of asthma was 16.3%; COPD 4.5%; and 'other chronic respiratory disease' 3.0%. Based on consensus categorisation (n = 483 complete records), "Wheezing in last 12 months" and "Waking up with a feeling of tightness" were the strongest predictors for asthma. For COPD, age and spirometry results were the strongest predictors. Practical challenges included logistics (participant recruitment; researcher safety); misinterpretation of questions due to local dialects; and assuring quality spirometry in the field. Conclusion: Detecting asthma in population surveys relies on symptoms and history. In contrast, spirometry and age were the best predictors of COPD. Logistical, language and spirometry-related challenges need to be addressed.


Assuntos
Asma , Doença Pulmonar Obstrutiva Crônica , Adulto , Asma/diagnóstico , Asma/epidemiologia , Estudos Transversais , Países em Desenvolvimento , Humanos , Prevalência , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Doença Pulmonar Obstrutiva Crônica/epidemiologia , Espirometria , Inquéritos e Questionários
7.
Adv Mater ; : e2107111, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34739745

RESUMO

Manipulating perovskite crystallization to prepare high-quality perovskite films is the key to achieve highly efficient and stable perovskite solar cells (PSCs). Here, we report a dynamic strategy to modulate perovskite crystallization using a resonance hole-transporting material (HTM) capable of fast self-adaptive tautomerization between multiple electronic states with neutral and charged resonance forms for mediating perovskite crystal growth and defects passivation in situ. This approach, based on resonance variation with self-adaptive molecular interactions between HTM and perovskite, produces high-quality perovskite films with smooth surface, oriented crystallization and low charge recombination, leading to high-performance inverted PSCs with power conversion efficiencies approaching to 22% for small-area devices (0.09 cm2 ) and up to 19.5% for large-area devices (1.02 cm2 ). Also, remarkably high stability of the PSCs was observed, retaining over 90%, 88%, or 83% of the initial efficiencies in air with relative humidity of 40∼50%, under continuous one-sun illumination, or at 75°C annealing for 1000 h without encapsulation. This article is protected by copyright. All rights reserved.

8.
Nanoscale ; 13(39): 16726-16733, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34596199

RESUMO

Cesium tin halide (CsSnX3, where X is halogen) perovskite nanocrystals (NCs) are one of the most representative alternatives to their lead-based cousins. However, a fundamental understanding of how to regulate the growth kinetics of colloidal CsSnX3 NCs is still lacking and, specifically, the role of surfactants in affecting their growth kinetics remains incompletely understood. Here we report a general approach for colloidal synthesis of CsSnX3 perovskite NCs through a judicious combination of capping agents. We demonstrate that introducing a small amount of zwitterionic phosphatidylcholine in the reaction is of vital importance for regulating the growth kinetics of CsSnX3 NCs, which otherwise merely leads to the formation of large-sized powders. Based on a range of experimental characterization, we propose that the formation of intermediate complexes between zwitterionic phosphatidylcholine and the precursors and the steric hindrance effect of branched fatty acid side-chains of phosphatidylcholine can regulate the growth kinetics of CsSnX3, which enables us to obtain CsSnX3 NCs with emission quantum yields among the highest values ever reported. Our finding of using zwitterionic capping agents to regulate the growth kinetics may inspire more research on the synthesis of high-quality tin-based perovskite NCs that could speed up their practical applications in optoelectronic devices.

9.
J Phys Chem Lett ; 12(42): 10402-10409, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34672588

RESUMO

Lead halide perovskites (LHPs) have attracted a tremendous amount of attention because of their applications in solar cells, lighting, and optoelectronics. However, the atomistic principles underlying their decomposition processes remain in large part obscure, likely due to the lack of precise information about their local structures and composition along regions with dimensions on the angstrom scale, such as crystal interfaces. Aberration-corrected scanning transmission electron microscopy combined with X-ray energy dispersive spectroscopy (EDS) is an ideal tool, in principle, for probing such information. However, atomic-resolution EDS has not been achieved for LHPs because of their instability under electron-beam irradiation. We report the fabrication of CsPbBr3 nanoplates with high beam stability through an interface-assisted regrowth strategy using cyanamide. The ultrahigh stability of the nanoplates primarily stems from two contributions: defect-healing self-assembly/regrowth processes and surface modulation by strong electron-withdrawing cyanamide molecules. The ultrahigh stability of as-prepared CsPbBr3 nanoplates enabled atomic-resolution EDS elemental mapping, which revealed atomically and elementally resolved details of the LHP nanostructures at an unprecedented level. While improving the stability of LHPs is critical for device applications, this work illustrates how improving the beam stability of LHPs is essential for addressing fundamental questions on structure-property relations in LHPs.

10.
PLoS One ; 16(10): e0258252, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34679104

RESUMO

BACKGROUND: Vaccine hesitancy is a complex, contested social phenomenon and existing research highlights the multifaceted role of trust in strengthening vaccine confidence. However, understanding public engagement with vaccination through the lens of (mis)trust requires more contextual evidence on trust's qualitative determinants. This includes expanding the geographic focus beyond current studies' focus on High Income Countries. Furthermore, obstacles remain in effectively integrating social science findings in the design of vaccine deployment strategies, and in ensuring that those who implement interventions and are affected by them are directly involved in producing knowledge about vaccination challenges. METHODS: We piloted a community-led ethnographic approach, training Community Health Workers (CHWs) in Kambia District, Sierra Leone, in qualitative social science methods. Methods included participant observation, participatory power mapping and rumour tracking, focus group discussions and key stakeholder interviews. CHWs, with the support of public health officials and professional social scientists, conducted research on vaccination challenges, analysed data, tested new community engagement strategies based on their findings and elicited local perspectives on these approaches. RESULTS: Our findings on vaccine confidence in five border communities highlighted three key themes: the impact of prior experiences with the health system on (mis)trust; relevance of livelihood strategies and power dynamics for vaccine uptake and access; and the contextual nature of knowledge around vaccines. Across these themes, we show how expressions of trust centered on social proximity, reliability and respect and the role of structural issues affecting both vaccine access and confidence. The pilot also highlighted the value and practical challenges to meaningfully co-designed research. CONCLUSION: There is scope for broader application of a community-led ethnographic approach will help redesign programming that is responsive to local knowledge and experience. Involving communities and low-cadre service providers in generating knowledge and solutions can strengthen relationships and sustain dialogue to bolster vaccine confidence.


Assuntos
Antropologia Cultural , Pesquisa Biomédica , Programas de Imunização , Características de Residência , Comportamento Social , Confiança , Vacinação , Grupos Focais , Pessoal de Saúde , Humanos , Serra Leoa , Vacinas/imunologia
11.
Adv Mater ; 33(45): e2103640, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34558117

RESUMO

Metal halide perovskite semiconductors have demonstrated remarkable potentials in solution-processed blue light-emitting diodes (LEDs). However, the unsatisfied efficiency and spectral stability responsible for trap-mediated non-radiative losses and halide phase segregation remain the primary unsolved challenges for blue perovskite LEDs. In this study, it is reported that a fluorene-based π-conjugated cationic polymer can be blended with the perovskite semiconductor to control film formation and optoelectronic properties. As a result, sky-blue and true-blue perovskite LEDs with Commission Internationale de l'Eclairage coordinates of (0.08, 0.22) and (0.12, 0.13) at the record external quantum efficiencies of 11.2% and 8.0% were achieved. In addition, the mixed halide perovskites with the conjugated cationic polymer exhibit excellent spectral stability under external bias. This result illustrates that π-conjugated cationic polymers have a great potential to realize efficient blue mixed-halide perovskite LEDs with stable electroluminescence.

12.
Nat Commun ; 12(1): 4831, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376647

RESUMO

Molecular additives are widely utilized to minimize non-radiative recombination in metal halide perovskite emitters due to their passivation effects from chemical bonds with ionic defects. However, a general and puzzling observation that can hardly be rationalized by passivation alone is that most of the molecular additives enabling high-efficiency perovskite light-emitting diodes (PeLEDs) are chelating (multidentate) molecules, while their respective monodentate counterparts receive limited attention. Here, we reveal the largely ignored yet critical role of the chelate effect on governing crystallization dynamics of perovskite emitters and mitigating trap-mediated non-radiative losses. Specifically, we discover that the chelate effect enhances lead-additive coordination affinity, enabling the formation of thermodynamically stable intermediate phases and inhibiting halide coordination-driven perovskite nucleation. The retarded perovskite nucleation and crystal growth are key to high crystal quality and thus efficient electroluminescence. Our work elucidates the full effects of molecular additives on PeLEDs by uncovering the chelate effect as an important feature within perovskite crystallization. As such, we open new prospects for the rationalized screening of highly effective molecular additives.

13.
Adv Sci (Weinh) ; 8(20): e2101125, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34449133

RESUMO

Perovskite quantum dots (QDs) are of interest for solution-processed lasers; however, their short Auger lifetime has limited lasing operation principally to the femtosecond temporal regime the photoexcitation levels to achieve optical gain threshold are up to two orders of magnitude higher in the nanosecond regime than in the femtosecond. Here the authors report QD superlattices in which the gain medium facilitates excitonic delocalization to decrease Auger recombination and in which the macroscopic dimensions of the structures provide the optical feedback required for lasing. The authors develope a self-assembly strategy that relies on sodiumd-an assembly director that passivates the surface of the QDs and induces self-assembly to form ordered three-dimensional cubic structures. A density functional theory model that accounts for the attraction forces between QDs allows to explain self-assembly and superlattice formation. Compared to conventional organic-ligand-passivated QDs, sodium enables higher attractive forces, ultimately leading to the formation of micron-length scale structures and the optical faceting required for feedback. Simultaneously, the decreased inter-dot distance enabled by the new ligand enhances exciton delocalization among QDs, as demonstrated by the dynamically red-shifted photoluminescence. These structures function as the lasing cavity and the gain medium, enabling nanosecond-sustained lasing with a threshold of 25 µJ cm-2 .

14.
J Am Chem Soc ; 143(29): 11026-11035, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34255513

RESUMO

Precise identification and in-depth understanding of defects in nanomaterials can aid in rationally modulating defect-induced functionalities. However, few studies have explored vacancy defects in ligand-stabilized metal nanoclusters with well-defined structures, owing to the substantial challenge of synthesizing and isolating such defective metal nanoclusters. Herein, a novel defective copper hydride nanocluster, [Cu36H10(PET)24(PPh3)6Cl2] (Cu36; PET: phenylethanethiolate; PPh3: triphenylphosphine), is successfully synthesized at the gram scale via a simple one-pot reduction method. Structural analysis reveals that Cu36 is a distorted half cubic nanocluster, evolved from the perfect Nichol's half cube. The two surface copper vacancies in Cu36 are found to be the principal imperfections, which result in some structural adjustments, including copper atom reconstruction near the vacancies as well as ligand modifications (e.g., substitution, migration, and exfoliation). Density functional theory calculations imply that the above-mentioned defects have a considerable influence on the electronic structure and properties. The modeling suggests that the formation of defective Cu36 rather than the perfect half cube is driven by the enlargement of the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the nanocluster. The structural evolution induced by the surface copper atom vacancies provides atomically precise insights into the defect-induced readjustment of the local structure and introduces new avenues for understanding the chemistry of defects in nanomaterials.

15.
Chem Rev ; 121(20): 12112-12180, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34251192

RESUMO

Oriented semiconductor nanostructures and thin films exhibit many advantageous properties, such as directional exciton transport, efficient charge transfer and separation, and optical anisotropy, and hence these nanostructures are highly promising for use in optoelectronics and photonics. The controlled growth of these structures can facilitate device integration to improve optoelectronic performance and benefit in-depth fundamental studies of the physical properties of these materials. Halide perovskites have emerged as a new family of promising and cost-effective semiconductor materials for next-generation high-power conversion efficiency photovoltaics and for versatile high-performance optoelectronics, such as light-emitting diodes, lasers, photodetectors, and high-energy radiation imaging and detectors. In this Review, we summarize the advances in the fabrication of halide perovskite nanostructures and thin films with controlled dimensionality and crystallographic orientation, along with their applications and performance characteristics in optoelectronics. We examine the growth methods, mechanisms, and fabrication strategies for several technologically relevant structures, including nanowires, nanoplates, nanostructure arrays, single-crystal thin films, and highly oriented thin films. We highlight and discuss the advantageous photophysical properties and remarkable performance characteristics of oriented nanostructures and thin films for optoelectronics. Finally, we survey the remaining challenges and provide a perspective regarding the opportunities for further progress in this field.

16.
Nat Commun ; 12(1): 3995, 2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34183646

RESUMO

Hot-carrier cooling processes of perovskite materials are typically described by a single parabolic band model that includes the effects of carrier-phonon scattering, hot phonon bottleneck, and Auger heating. However, little is known (if anything) about the cooling processes in which the spin-degenerate parabolic band splits into two spin-polarized bands, i.e., the Rashba band splitting effect. Here, we investigated the hot-carrier cooling processes for two slightly different compositions of two-dimensional Dion-Jacobson hybrid perovskites, namely, (3AMP)PbI4 and (4AMP)PbI4 (3AMP = 3-(aminomethyl)piperidinium; 4AMP = 4-(aminomethyl)piperidinium), using a combination of ultrafast transient absorption spectroscopy and first-principles calculations. In (4AMP)PbI4, upon Rashba band splitting, the spin-dependent scattering of hot electrons is responsible for accelerating hot-carrier cooling at longer delays. Importantly, the hot-carrier cooling of (4AMP)PbI4 can be extended by manipulating the spin state of the hot carriers. Our findings suggest a new approach for prolonging hot-carrier cooling in hybrid perovskites, which is conducive to further improving the performance of hot-carrier-based optoelectronic and spintronic devices.

17.
J Phys Chem Lett ; 12(20): 4917-4927, 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34008983

RESUMO

Highly luminescent metal-organic frameworks (MOFs) have recently received great attention due to their potential applications as sensors and light-emitting devices. In these MOFs, the highly ordered fluorescent organic linkers positioning prevents excited-state self-quenching and rotational motion, enhancing their light-harvesting properties. Here, the exciton migration between the organic linkers with the same chemical structure but different protonation degrees in Zr-based MOFs was explored and deciphered using ultrafast laser spectroscopy and density functional theory calculations. First, we clearly demonstrate how hydrogen-bonding interactions between free linkers and solvents affect the twisting changes, internal conversion processes, and luminescent behavior of a benzoimidazole-based linker. Second, we provide clear evidence of an ultrafast energy transfer between well-aligned adjacent linkers with different protonation states inside the MOF. These findings provide a new fundamental photophysical insight into the exciton migration dynamics between linkers with different protonation states coexisting at different locations in MOFs and serve as a benchmark for improving light-harvesting MOF architectures.

18.
New Microbes New Infect ; 41: 100888, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33936745

RESUMO

Clinical descriptions about influenza-like illness in children seem non-specific during the co-circulation of SARS-CoV-2 and influenza. This paper aimed to summarize recent studies comparing clinical features and outcome, laboratory and radiological findings of COVID-19 patients with influenza patients in the paediatric population.

19.
Angew Chem Int Ed Engl ; 60(29): 16164-16170, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-33982380

RESUMO

The all-inorganic nature of CsPbI3 perovskites allows to enhance stability in perovskite devices. Research efforts have led to improved stability of the black phase in CsPbI3 films; however, these strategies-including strain and doping-are based on organic-ligand-capped perovskites, which prevent perovskites from forming the close-packed quantum dot (QD) solids necessary to achieve high charge and thermal transport. We developed an inorganic ligand exchange that leads to CsPbI3 QD films with superior phase stability and increased thermal transport. The atomic-ligand-exchanged QD films, once mechanically coupled, exhibit improved phase stability, and we link this to distributing strain across the film. Operando measurements of the temperature of the LEDs indicate that KI-exchanged QD films exhibit increased thermal transport compared to controls that rely on organic ligands. The LEDs exhibit a maximum EQE of 23 % with an electroluminescence emission centered at 640 nm (FWHM: ≈31 nm). These red LEDs provide an operating half-lifetime of 10 h (luminance of 200 cd m-2 ) and an operating stability that is 6× higher than that of control devices.

20.
Clin Lab ; 67(5)2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33978358

RESUMO

BACKGROUND: Tumor associated macrophages have been implicated in the pathogenesis of classical Hodgkin's lymphoma and have been suggested to have a negative impact on outcome. The aim of this study is to determine the expression and the prognostic impact of CD163 and CD68 markers of the tumor associated macrophages, in the initial positively infiltrated bone marrow biopsy specimens of our subjects by immunohistochemistry and to corre¬late their expression with other clinical and laboratory prognostic factors. METHODS: This study was conducted on fifty-one patients with de novo classical Hodgkin's lymphoma, presenting to the Clinical Pathology Department at the National Cancer Institute, Cairo University. CD163 and CD68 were detected in the initial bone marrow biopsy specimens from our subjects by immunohistochemistry. RESULTS: The present study included 51 patients with CHL. They comprised 24 males (47.1%) and 27 females (52.9%) with an age of 32.9 ± 14.5 years. After treatment, 33 patients (64.7%) achieved complete remission while 18 patients (35.3%) failed. Comparison between patients with CR and patients without revealed significantly lower CD68 expression [median (IQR): 30.0 (15.0 - 47.5%) versus 55.0 (43.8 - 55.0%), p = 0.003] and CD163 expression [25.0 (10.0 - 37.5%) versus 45.0 (0.35 - 55.0%)] in CR patients. Binary logistic regression analysis identified CD68 and CD163 expressions as significant predictors of CR in univariate and multivariate analyses. CONCLUSIONS: The expressions of both tumor-associated markers, CD68 and CD163, are significant predictors of CR in patients with CHL.


Assuntos
Doença de Hodgkin , Adolescente , Adulto , Antígenos CD , Antígenos de Diferenciação Mielomonocítica , Intervalo Livre de Doença , Feminino , Doença de Hodgkin/diagnóstico , Humanos , Imuno-Histoquímica , Macrófagos , Masculino , Pessoa de Meia-Idade , Prognóstico , Receptores de Superfície Celular , Macrófagos Associados a Tumor , Adulto Jovem
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