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1.
Nature ; 2024 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-38977018

RESUMEN

Two-dimensional (2D)/three-dimensional (3D) perovskite heterostructures have played a key role in advancing the performance of perovskite solar cells (PSCs)1,2. However, the migration of cations between 2D and 3D layers results in the disruption of octahedral networks that leads to degradation in performance over time3,4. We hypothesized that perovskitoids, with robust organic-inorganic networks enabled by edge- and face-sharing, could impede ion migration. We explored a set of perovskitoids of varying dimensionality, and found that cation migration within perovskitoid/perovskite heterostructures was suppressed compared to the 2D/3D perovskite case. Increasing the dimensionality of perovskitoids improves charge transport when they are interfaced with 3D perovskite surfaces - this the result of enhanced octahedral connectivity and out-of-plane orientation. The 2D perovskitoid (A6BfP)8Pb7I22 (A6BfP: N-aminohexyl-benz[f]-phthalimide) provides efficient passivation of perovskite surfaces and enables uniform large-area perovskite films. Devices based on perovskitoid/perovskite heterostructures achieve a certified quasi-steady-state power conversion efficiency of 24.6% for centimeter-area PSCs. We removed the fragile hole transport layers and showed stable operation of the underlying perovskitoid/perovskite heterostructure at 85°C for 1,250 hours for encapsulated large-area devices in an air ambient.

2.
Nature ; 620(7975): 776-781, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37468632

RESUMEN

Design-specific control over the transitions between excited electronic states with different spin multiplicities is of the utmost importance in molecular and materials chemistry1-3. Previous studies have indicated that the combination of spin-orbit and vibronic effects, collectively termed the spin-vibronic effect, can accelerate quantum-mechanically forbidden transitions at non-adiabatic crossings4,5. However, it has been difficult to identify precise experimental manifestations of the spin-vibronic mechanism. Here we present coherence spectroscopy experiments that reveal the interplay between the spin, electronic and vibrational degrees of freedom that drive efficient singlet-triplet conversion in four structurally related dinuclear Pt(II) metal-metal-to-ligand charge-transfer (MMLCT) complexes. Photoexcitation activates the formation of a Pt-Pt bond, launching a stretching vibrational wavepacket. The molecular-structure-dependent decoherence and recoherence dynamics of this wavepacket resolve the spin-vibronic mechanism. We find that vectorial motion along the Pt-Pt stretching coordinates tunes the singlet and intermediate-state energy gap irreversibly towards the conical intersection and subsequently drives formation of the lowest stable triplet state in a ratcheting fashion. This work demonstrates the viability of using vibronic coherences as probes6-9 to clarify the interplay among spin, electronic and nuclear dynamics in spin-conversion processes, and this could inspire new modular designs to tailor the properties of excited states.

3.
Chem Rev ; 124(9): 5421-5469, 2024 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-38663009

RESUMEN

Utilization of renewable energies for catalytically generating value-added chemicals is highly desirable in this era of rising energy demands and climate change impacts. Artificial photosynthetic systems or photocatalysts utilize light to convert abundant CO2, H2O, and O2 to fuels, such as carbohydrates and hydrogen, thus converting light energy to storable chemical resources. The emergence of intense X-ray pulses from synchrotrons, ultrafast X-ray pulses from X-ray free electron lasers, and table-top laser-driven sources over the past decades opens new frontiers in deciphering photoinduced catalytic reaction mechanisms on the multiple temporal and spatial scales. Operando X-ray spectroscopic methods offer a new set of electronic transitions in probing the oxidation states, coordinating geometry, and spin states of the metal catalytic center and photosensitizers with unprecedented energy and time resolution. Operando X-ray scattering methods enable previously elusive reaction steps to be characterized on different length scales and time scales. The methodological progress and their application examples collected in this review will offer a glimpse into the accomplishments and current state in deciphering reaction mechanisms for both natural and synthetic systems. Looking forward, there are still many challenges and opportunities at the frontier of catalytic research that will require further advancement of the characterization techniques.

4.
J Am Chem Soc ; 146(23): 16128-16147, 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38815003

RESUMEN

One of the primary methods for band gap tuning in metal halide perovskites has been halide (I/Br) mixing. Despite widespread usage of this type of chemical substitution in perovskite photovoltaics, there is still little understanding of the structural impacts of halide alloying, with the assumption being the formation of ideal solid solutions. The FASnI3-xBrx (x = 0-3) family of compounds provides the first example where the assumption breaks down, as the composition space is broken into two unique regimes (x = 0-2.9; x = 2.9-3) based on their average structure with the former having a 3D and the latter having an extended 3D (pseudo 0D) structure. Pair distribution function (PDF) analyses further suggest a dynamic 5s2 lone pair expression resulting in increasing levels of off-centering of the central Sn as the Br concentration is increased. These antiferroelectric distortions indicate that even the x = 0-2.9 phase space behaves as a nonideal solid-solution on a more local scale. Solid-state NMR confirms the difference in local structure yielding greater insight into the chemical nature and local distributions of the FA+ cation. In contrast to the FAPbI3-xBrx series, a drastic photoluminescence (PL) quenching is observed with x ≥ 1.9 compounds having no observable PL. Our detailed studies attribute this quenching to structural transitions induced by the distortions of the [SnBr6] octahedra in response to stereochemically expressed lone pairs of electrons. This is confirmed through density functional theory, having a direct impact on the electronic structure.

5.
Clin Radiol ; 79(1): e119-e126, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37940443

RESUMEN

AIM: To evaluate whether abnormalities in white matter (WM) integrity are present in young children with epilepsy. MATERIALS AND METHODS: Twelve children (3-6 years old) with epilepsy and six matched healthy controls were recruited for brain diffusion tensor imaging (DTI). Track-based spatial statistics (TBSS) was used to analyse and compare DTI indices of mean diffusivity (MD), fractional anisotropy (FA), axial and radial diffusivity (AD/RD) between patients and controls, and correlations between clinical variables and DTI parameters were analysed. RESULTS: Compared with controls, patients showed increased FA in the left superior corona radiata and increased AD in the bilateral superior corona radiata. In children with generalised epilepsy, FA was increased in the left external capsule, while AD was decreased in the body of the corpus callosum, the left external capsule and the left superior longitudinal fasciculus. In those with focal epilepsy, FA was increased in the genu and body of the corpus callosum, and RD was decreased in the genu of the corpus callosum and left external capsule. Compared with partial epilepsy, generalised epilepsy was associated with increased FA in the right anterior corona radiata and decreased RD in the right anterior corona radiata and the genu and body of the corpus callosum. No significant correlations were observed between clinical variables and DTI parameters. CONCLUSIONS: The results of this study indicate that the microstructure of the white matter is disturbed by epileptic discharges and a compensatory response occurs during early brain development.


Asunto(s)
Epilepsias Parciales , Epilepsia , Sustancia Blanca , Niño , Humanos , Preescolar , Sustancia Blanca/diagnóstico por imagen , Imagen de Difusión Tensora/métodos , Encéfalo/diagnóstico por imagen , Epilepsia/diagnóstico por imagen , Anisotropía
6.
J Chem Phys ; 160(14)2024 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-38619061

RESUMEN

Solar fuels catalysis is a promising route to efficiently harvesting, storing, and utilizing abundant solar energy. To achieve this promise, however, molecular systems must be designed with sustainable components that can balance numerous photophysical and chemical processes. To that end, we report on the structural and photophysical characterization of a series of Cu(I)-anthraquinone-based electron donor-acceptor dyads. The dyads utilized a heteroleptic Cu(I) bis-diimine architecture with a copper(I) bis-phenanthroline chromophore donor and anthraquinone electron acceptor. We characterized the structures of the complexes using x-ray crystallography and density functional theory calculations and the photophysical properties via resonance Raman and optical transient absorption spectroscopy. The calculations and resonance Raman spectroscopy revealed that excitation of the Cu(I) metal-to-ligand charge-transfer (MLCT) transition transfers the electron to a delocalized ligand orbital. The optical transient absorption spectroscopy demonstrated that each dyad formed the oxidized copper-reduced anthraquinone charge-separated state. Unlike most Cu(I) bis-phenanthroline complexes where increasingly bulky substituents on the phenanthroline ligands lead to longer MLCT excited-state lifetimes, here, we observe a decrease in the long-lived charge-separated state lifetime with increasing steric bulk. The charge-separated state lifetimes were best explained in the context of electron-transfer theory rather than with the energy gap law, which is typical for MLCT excited states, despite the complete conjugation between the phenanthroline and anthraquinone moieties.

7.
J Chem Phys ; 161(3)2024 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-39007394

RESUMEN

The unfolding dynamics of ubiquitin were studied using a combination of x-ray solution scattering (XSS) and molecular dynamics (MD) simulations. The kinetic analysis of the XSS ubiquitin signals showed that the protein unfolds through a two-state process, independent of the presence of destabilizing salts. In order to characterize the ensemble of unfolded states in atomic detail, the experimental XSS results were used as a constraint in the MD simulations through the incorporation of x-ray scattering derived potential to drive the folded ubiquitin structure toward sampling unfolded states consistent with the XSS signals. We detail how biased MD simulations provide insight into unfolded states that are otherwise difficult to resolve and underscore how experimental XSS data can be combined with MD to efficiently sample structures away from the native state. Our results indicate that ubiquitin samples unfolded in states with a high degree of loss in secondary structure yet without a collapse to a molten globule or fully solvated extended chain. Finally, we propose how using biased-MD can significantly decrease the computational time and resources required to sample experimentally relevant nonequilibrium states.


Asunto(s)
Simulación de Dinámica Molecular , Desplegamiento Proteico , Ubiquitina , Ubiquitina/química , Difracción de Rayos X , Cinética
8.
J Endocrinol Invest ; 47(1): 67-77, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37270749

RESUMEN

PURPOSE: To evaluate the genotypic and phenotypic relationship in a large cohort of OI patients and to compare the differences between eastern and western OI cohorts. METHODS: A total of 671 OI patients were included. Pathogenic mutations were identified, phenotypic information was collected, and relationships between genotypes and phenotypes were analyzed. Literature about western OI cohorts was searched, and differences were compared between eastern and western OI cohorts. RESULTS: A total of 560 OI patients were identified as carrying OI pathogenic mutations, and the positive detection rate of disease-causing gene mutations was 83.5%. Mutations in 15 OI candidate genes were identified, with COL1A1 (n = 308, 55%) and COL1A2 (n = 164, 29%) being the most common mutations, and SERPINF1 and WNT1 being the most common biallelic variants. Of the 414 probands, 48.8, 16.9, 29.2 and 5.1% had OI types I, III, IV and V, respectively. Peripheral fracture was the most common phenotype (96.6%), and femurs (34.7%) were most commonly affected. Vertebral compression fracture was observed in 43.5% of OI patients. Biallelic or COL1A2 mutation led to more bone deformities and poorer mobility than COL1A1 mutation (all P < 0.05). Glycine substitution of COL1A1 or COL1A2 or biallelic variants led to more severe phenotypes than haploinsufficiency of collagen type I α chains, which induced the mildest phenotypes. Although the gene mutation spectrum varied among countries, the fracture incidence was similar between eastern and western OI cohorts. CONCLUSION: The findings are valuable for accurate diagnosis and treatment of OI, mechanism exploration and prognosis judgment. Genetic profiles of OI may vary among races, but the mechanism needs to be explored.


Asunto(s)
Enfermedades Óseas Metabólicas , Fracturas por Compresión , Osteogénesis Imperfecta , Fracturas de la Columna Vertebral , Humanos , Osteogénesis Imperfecta/genética , Cadena alfa 1 del Colágeno Tipo I , Colágeno Tipo I/genética , Genotipo , Fenotipo , Mutación
9.
J Endocrinol Invest ; 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38744806

RESUMEN

PURPOSE: We aim to detect serum DKK1 level of pediatric patients with OI and to analyze its relationship with the genotype and phenotype of OI patients. METHODS: A cohort of pediatric OI patients and age-matched healthy children were enrolled. Serum levels of DKK1 and bone turnover biomarkers were measured by enzyme-linked immunosorbent assay. Bone mineral density (BMD) was measured by Dual-energy X-ray absorptiometry. Pathogenic mutations of OI were detected by next-generation sequencing and confirmed by Sanger sequencing. RESULTS: A total of 62 OI children with mean age of 9.50 (4.86, 12.00) years and 29 healthy children were included in this study. The serum DKK1 concentration in OI children was significantly higher than that in healthy children [5.20 (4.54, 6.32) and 4.08 (3.59, 4.92) ng/mL, P < 0.001]. The serum DKK1 concentration in OI children was negatively correlated with height (r = - 0.282), height Z score (r = - 0.292), ALP concentration (r = - 0.304), lumbar BMD (r = - 0.276), BMD Z score of the lumbar spine and femoral neck (r = - 0.32; r = - 0.27) (all P < 0.05). No significant difference in serum DKK1 concentration was found between OI patients with and without vertebral compression fractures. In patients with spinal deformity (22/62), serum DKK1 concentration was positively correlated with SDI (r = 0.480, P < 0.05). No significant correlation was observed between serum DKK1 concentration and the annual incidence of peripheral fractures, genotype and types of collagen changes in OI children. CONCLUSION: The serum DKK1 level was not only significantly elevated in OI children, but also closely correlated to their skeletal phenotype, suggesting that DKK1 may become a new biomarker and a potential therapeutic target of OI.

10.
Proc Natl Acad Sci U S A ; 118(14)2021 04 06.
Artículo en Inglés | MEDLINE | ID: mdl-33782122

RESUMEN

Ultrafast structural dynamics with different spatial and temporal scales were investigated during photodissociation of carbon monoxide (CO) from iron(II)-heme in bovine myoglobin during the first 3 ps following laser excitation. We used simultaneous X-ray transient absorption (XTA) spectroscopy and X-ray transient solution scattering (XSS) at an X-ray free electron laser source with a time resolution of 80 fs. Kinetic traces at different characteristic X-ray energies were collected to give a global picture of the multistep pathway in the photodissociation of CO from heme. In order to extract the reaction coordinates along different directions of the CO departure, XTA data were collected with parallel and perpendicular relative polarizations of the laser pump and X-ray probe pulse to isolate the contributions of electronic spin state transition, bond breaking, and heme macrocycle nuclear relaxation. The time evolution of the iron K-edge X-ray absorption near edge structure (XANES) features along the two major photochemical reaction coordinates, i.e., the iron(II)-CO bond elongation and the heme macrocycle doming relaxation were modeled by time-dependent density functional theory calculations. Combined results from the experiments and computations reveal insight into interplays between the nuclear and electronic structural dynamics along the CO photodissociation trajectory. Time-resolved small-angle X-ray scattering data during the same process are also simultaneously collected, which show that the local CO dissociation causes a protein quake propagating on different spatial and temporal scales. These studies are important for understanding gas transport and protein deligation processes and shed light on the interplay of active site conformational changes and large-scale protein reorganization.


Asunto(s)
Monóxido de Carbono/química , Simulación de Dinámica Molecular , Mioglobina/química , Animales , Bovinos , Hemo/química , Hemo/metabolismo , Hierro/química , Mioglobina/metabolismo , Unión Proteica
11.
Zhonghua Yi Xue Za Zhi ; 104(26): 2409-2416, 2024 Jul 09.
Artículo en Zh | MEDLINE | ID: mdl-38978364

RESUMEN

Objective: To compare the efficacy of gasless robotic surgery through transaxillary approach and open surgery for papillary thyroid carcinoma (PTC). Methods: The data of patient undergoing robotic surgery through transaxillary approach and traditional open surgery for PTC at the Sun Yat-sen Memorial Hospital, Sun Yat-sen University, from November 2016 to June 2023 were retrospectively analyzed. A 1∶1 propensity score matching (PSM) was performed to balance age, sex, extent of surgery, tumor size, capsule invasion, and multifocality. Surgical data, postoperative pathological data, complications, postoperative 2-month visual analog scale (VAS) scores for aesthetics, and follow-up data were compared between the two groups. Results: A total of 728 PTC patients were included. There were 339 patients in the robotic group, among which 262 were female (77.3%) and 77 were male (22.7%), with the age of [M (Q1, Q3)] 39 (32, 46) years and a body mass index (BMI) of 22.8 (20.7, 25.0) kg/m². Meanwhile, 389 patients were in the open group, among which 290 were female (74.6%) and 99 were male (25.4%), with the age of 47 (38, 55) years and a BMI of 23.2 (21.3, 25.5) kg/m2. Further analysis after PSM (there were 264 cases in both groups) showed that in the subtotal thyroidectomy and central neck dissection (LT+CCND) subgroup, the robotic group had longer operative time, higher blood loss, and greater drainage volume compared with the open group [100 (80, 130) min vs 60 (50, 80) min; 10 (10, 20) ml vs 10 (10, 20) ml; 103 (69, 145) ml vs 75 (57, 98) ml; all P<0.001], and the central lymph node metastasis rate was higher in the robotic group [45.6% (57/125) vs 31.8% (47/148), P=0.019]. In the total thyroidectomy and central neck dissection (TT+CCND) subgroup, the robotic group also had longer operative time, higher blood loss, and greater drainage volume compared with the open group [150 (110, 180) min vs 85 (75, 100) min; 20 (10, 20) ml vs 10 (10, 20) ml; 155 (107, 206) ml vs 90 (70, 120) ml; all P<0.001]. The incidence of chest skin numbness at 3 months postoperatively was higher in the robotic group compared with the open group (12.9% vs 0, P<0.001), while there were no statistically significant differences in other postoperative complications (all P>0.05). The VAS score at 2 months postoperatively was higher in the robotic group compared with the open group [9 (9, 9) vs 8 (7, 9), P<0.001]. Three cases of contralateral lobe recurrence occurred in the open group, while there were no case of recurrence in the robotic group. The 5-year overall survival rate was 100.0% in both the robotic and open groups, and there was no statistically significant difference in the 5-year disease-free survival rate between the robotic and open groups (100.0% vs 98.6%, P=0.068). Conclusion: Gasless robotic surgery through transaxillary approach for total thyroidectomy or lobectomy in the treatment of PTC is safe, feasible, and effective, with good cosmetic outcomes and comparable efficacy to traditional surgery.


Asunto(s)
Axila , Procedimientos Quirúrgicos Robotizados , Cáncer Papilar Tiroideo , Neoplasias de la Tiroides , Tiroidectomía , Humanos , Procedimientos Quirúrgicos Robotizados/métodos , Masculino , Femenino , Cáncer Papilar Tiroideo/cirugía , Adulto , Estudios Retrospectivos , Neoplasias de la Tiroides/cirugía , Persona de Mediana Edad , Tiroidectomía/métodos , Resultado del Tratamiento , Tempo Operativo , Puntaje de Propensión
12.
Zhonghua Yu Fang Yi Xue Za Zhi ; 58(1): 40-47, 2024 Jan 06.
Artículo en Zh | MEDLINE | ID: mdl-38228548

RESUMEN

Objective: To study the complete genome characterization of Human Astrovirus (HAstV) in Shandong Province. Methods: Stool samples from acute flaccid paralysis (AFP) surveillance in Shandong Province from 2020 to 2022 were collected, and HAstV nucleic acid was examined by real-time quantitative PCR (qPCR). Next-generation sequencing (NGS) was conducted for the positive samples to obtain complete genome sequences and identify the genotype. Homology comparison and phylogenetic analysis were performed by using BioEdit and Mega software. Results: A total of 667 samples were examined by qPCR, of which 14 were HAstV-positive (2.1%), including HAstV-1 (n=6), MLB1 (n=6), MLB2 (n=1), and VA2 (n=1). The complete genome sequences were obtained from 11 samples. The six HAstV-1 sequences of this study had 98.2% to 99.9% nt similarities with each other and 87.6% to 98.6% with those from other regions. The four MLB1 sequences of this study had 99.1% to 99.9% nt similarities with each other and 92.2% to 99.4% with those from other regions. The VA2 sequence of this study had 96.0% to 96.3% nt similarities with those from other regions. Phylogenetic analysis based on ORF2 region showed that the local HAstV-1 sequences were most closely related to Japanese strains, and had distinct topology with phylogenies based on ORF1a and ORF1b regions. Conclusion: The complete genome sequences of 11 HAstV strains are obtained, and the VA2 complete genome is found.


Asunto(s)
Infecciones por Astroviridae , Mamastrovirus , Humanos , Mamastrovirus/genética , Filogenia , Infecciones por Astroviridae/epidemiología , Heces , Análisis de Secuencia de ADN , Genotipo , Reacción en Cadena en Tiempo Real de la Polimerasa
13.
Zhonghua Bing Li Xue Za Zhi ; 53(3): 282-287, 2024 Mar 08.
Artículo en Zh | MEDLINE | ID: mdl-38433057

RESUMEN

Objective: To investigate the endoscopic and histopathological features, diagnosis and differential diagnosis of gastric hamartomatous inverted polyp (GHIP). Methods: Five cases of GHIP were collected at the University Town Hospital of Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China, from May 2021 to May 2023. The endoscopic, pathological and immunohistochemical features of the 5 GHIP cases were analyzed. The relevant literature was reviewed. Results: There were 3 males and 2 females, aged from 49 to 60 years, with a mean age of 56 years. The lesions were located in the fundus and body of the stomach, and presented as polyps or masses under endoscopy. Microscopically, the lesions were mainly in the submucosa and consisted of lobulated or clustered gastric glandular epithelium surrounded by hyperplastic smooth muscle. In some areas, there were differentiated glandular elements mimicking the normal gastric mucosa. The irregularly dilated glandular elements in the center were lined by hyperplastic foveolar epithelium, while the glands in the periphery were fundic or pyloric glands. In addition, in some areas, the glands showed cystic expansion, disordered arrangement and lack of differentiation. The hyperplastic glandular epithelium included foveolar epithelium, fundic gland and pyloric gland. There were scattered neuroendocrine cells and smooth muscle bundles in the stroma. Immunohistochemically, the tumor cells were positive for MUC5AC, MUC6, Pepsinogen Ⅰ and H+/K+ ATPase ß, but negative for MUC2. The scattered neuroendocrine cells were positive for synaptophysin, and the desmin stain highlighted hyperplastic smooth muscle bundles. One case was classified as type 2 gastric inverted polyp, and 4 cases were classified as type 3. Conclusions: GHIP is a rare gastric polyp with unique histological features. It should be distinguished from inverted hyperplastic polyp, gastritis cystica profunda, adenomyoma, hyperplastic polyps and well-differentiated gastric tubular adenocarcinoma, etc. Improving the understanding of its pathogenesis and diagnostic features can help avoid misdiagnoses.


Asunto(s)
Pólipos Adenomatosos , Pólipos , Neoplasias Gástricas , Femenino , Masculino , Humanos , Persona de Mediana Edad , Pólipos/cirugía , Epitelio
14.
Niger J Clin Pract ; 27(5): 599-603, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38842709

RESUMEN

BACKGROUND AND AIM: Preeclampsia, a pregnancy complication associated with significant maternal and perinatal mortality and morbidity, has been found to be closely linked to dysfunction in the blood coagulation-fibrinolysis system. However, the relationship between hematologic data and severity and onset time of preeclampsia remains unclear. This study aimed to identify specific hematologic parameters in both preeclamptic and normotensive pregnant women and determine their potential significance in the pathogenesis of preeclampsia. MATERIALS AND METHODS: A total of 112 patients with gestational hypertension disease were divided into two groups: early-onset preeclampsia (32 cases) and late-onset preeclampsia (80 cases). A control group of 82 normotensive pregnant women matched for age and parity was also selected. Blood samples were collected from all participants to test for specific hematologic parameters. RESULTS: Mild and severe preeclampsia were associated with lower hemoglobin level (P = 0.01 and P = 0.03, respectively), higher mean platelet volume (P = 0.01 and P = 0.01, respectively) and fibrinogen (P = 0.01 and P = 0.01, respectively), and shorter prothrombin time (P = 0.02 and P = 0.01, respectively) and activated partial thromboplastin time (P = 0.01 and P = 0.02, respectively). CONCLUSION: These findings have provided evidence on the hematologic coagulative actors in the pathogenesis and severity of preeclampsia.


Asunto(s)
Preeclampsia , Humanos , Femenino , Embarazo , Adulto , Preeclampsia/sangre , Preeclampsia/fisiopatología , Preeclampsia/diagnóstico , Estudios de Casos y Controles , Hipertensión Inducida en el Embarazo/sangre , Hipertensión Inducida en el Embarazo/fisiopatología , Coagulación Sanguínea/fisiología , Índice de Severidad de la Enfermedad , Adulto Joven , Fibrinógeno/metabolismo , Fibrinógeno/análisis , Tiempo de Protrombina , Volúmen Plaquetario Medio , Hemoglobinas/análisis , Tiempo de Tromboplastina Parcial
15.
J Am Chem Soc ; 145(51): 27975-27983, 2023 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-38085867

RESUMEN

Chemically stable metal-organic frameworks (MOFs) featuring interconnected hierarchical pores have proven to be promising for a remarkable variety of applications. Nevertheless, the framework's susceptibility to capillary-force-induced pore collapse, especially during water evacuation, has often limited practical applications. Methodologies capable of predicting the relative magnitudes of these forces as functions of the pore size, chemical composition of the pore walls, and fluid loading would be valuable for resolution of the pore collapse problem. Here, we report that a molecular simulation approach centered on evacuation-induced nanocavitation within fluids occupying MOF pores can yield the desired physical-force information. The computations can spatially pinpoint evacuation elements responsible for collapse and the chemical basis for mitigation of the collapse of modified pores. Experimental isotherms and difference-electron density measurements of the MOF NU-1000 and four chemical variants validate the computational approach and corroborate predictions regarding relative stability, anomalous sequence of pore-filling, and chemical basis for mitigation of destructive forces.

16.
Opt Express ; 31(23): 38475-38493, 2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-38017953

RESUMEN

The agile generation and control of multiple optical frequency modes combined with the realtime processing of multi-mode data provides access to experimentation in domains such as optomechanical systems, optical information processing, and multi-mode spectroscopy. The latter, specifically spectroscopy of spectral-hole burning (SHB), has motivated our development of a multi-mode heterodyne laser interferometric scheme centered around a software-defined radio platform for signal generation and processing, with development in an entirely open-source environment. A challenge to SHB is the high level of shot noise due to the laser power constraint imposed by the spectroscopic sample. Here, we have demonstrated the production, detection, and separation of multiple optical frequency modes to the benefit of optical environment sensing for realtime phase noise subtraction as well as shot noise reduction through multi-mode averaging. This has allowed us to achieve improved noise performance in low-optical-power interferometry. Although our target application is laser stabilization via SHB in cryogenic temperature rare-earth doped crystals, these techniques may be employed in a variety of different contexts.

17.
Inorg Chem ; 62(35): 14368-14376, 2023 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-37620247

RESUMEN

A key challenge to the effective utilization of solar energy is to promote efficient photoinduced charge transfer, specifically avoiding unproductive, circuitous electron-transfer pathways and optimizing the kinetics of charge separation and recombination. We hypothesize that one way to address this challenge is to develop a fundamental understanding of how to initiate and control directional photoinduced charge transfer, particularly for earth-abundant first-row transition-metal coordination complexes, which typically suffer from relatively short excited-state lifetimes. Here, we report a series of functionalized heteroleptic copper(I)bis(phenanthroline) complexes, which have allowed us to investigate the directionality of intramolecular photoinduced metal-to-ligand charge transfer (MLCT) as a function of the substituent Hammett parameter. Ultrafast transient absorption suggests a complicated interplay of MLCT localization and solvent interaction with the Cu(II) center of the MLCT state. This work provides a set of design principles for directional charge transfer in earth-abundant complexes and can be used to efficiently design pathways for connecting the molecular modules to catalysts or electrodes and integration into systems for light-driven catalysis.

18.
J Phys Chem A ; 127(8): 1831-1838, 2023 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-36800527

RESUMEN

Bimetallic electron donor-acceptor complexes can facilitate electron and energy transfer with excellent structural control through synthetic design. In this work, we investigate the photochemical dynamics in a Ru-Cu bimetallic complex after photoexcitation of the Ru-centered charge transfer state. The physical underpinnings of the metal-to-metal directional charge transfer process are unraveled via analyses of the quantum electronic dynamics and electron-nuclear trajectories. The effects of molecular vibrations in the photoexcited state on the charge transfer processes are also analyzed.

19.
Nature ; 543(7647): 647-656, 2017 03 29.
Artículo en Inglés | MEDLINE | ID: mdl-28358065

RESUMEN

Coherence phenomena arise from interference, or the addition, of wave-like amplitudes with fixed phase differences. Although coherence has been shown to yield transformative ways for improving function, advances have been confined to pristine matter and coherence was considered fragile. However, recent evidence of coherence in chemical and biological systems suggests that the phenomena are robust and can survive in the face of disorder and noise. Here we survey the state of recent discoveries, present viewpoints that suggest that coherence can be used in complex chemical systems, and discuss the role of coherence as a design element in realizing function.


Asunto(s)
Biofisica , Modelos Biológicos , Modelos Químicos , Electrones , Transferencia de Energía , Metales/química , Modelos Moleculares , Movimiento (Física) , Teoría Cuántica , Análisis Espectral , Factores de Tiempo , Vibración
20.
Clin Radiol ; 78(5): 375-380, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36805286

RESUMEN

AIM: To investigate whether spleen imaging characteristics of baseline 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) positron-emission tomography (PET)/computed tomography (CT) can help to predict the clinical outcome in complete response (CR) diffuse large B-cell lymphoma (DLBCL). MATERIALS AND METHODS: Three hundred and six patients with DLBCL were enrolled in the study and divided into recurrence and non-recurrence groups. The splenic abnormalities were compared using the chi-square test and quantitative indexes were compared using the t-test. The Cox proportional hazard regression model was used for univariate and multivariate analysis. Kaplan-Meier curves and log-rank tests were used to compare progression-free survival (PFS). Propensity score matching (PSM) was used to match patients with and without splenic abnormalities according to age, gender, and initial Ann Arbor stage at a 1:2 ratio (52:104); then the recurrence and PFS results were compared again. RESULTS: Age, international prognostic index (IPI), stage, splenomegaly, and focal splenic lesions were significantly different between the recurrence and non-recurrence groups. IPI, stage, baseline spleen mean standard uptake value (SUVmean)/liver SUVmean, splenomegaly, and focal lesions were selected by Cox single-factor analysis, and only focal lesions showed a statistical difference in terms of Cox multivariate analysis (p=0.022, hazard ratio [HR]: 2.843). After PSM, focal splenic lesions (n=20) were still statistically different (p=0.003) between the recurrence and non-recurrence groups, and this played an essential role in PFS forecasting (p=0.0004, HR: 3.767). CONCLUSION: Focal splenic lesions were identified as an independent risk factor for the prognosis of DLBCL. Pretreatment splenomegaly and focal splenic lesions appeared to be related to the relapse and PFS of DLBCL patients. Focal splenic lesions still showed meaningful predictive value even with propensity matching.


Asunto(s)
Linfoma de Células B Grandes Difuso , Enfermedades del Bazo , Humanos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Fluorodesoxiglucosa F18 , Pronóstico , Esplenomegalia , Estudios Retrospectivos , Recurrencia Local de Neoplasia , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Tomografía de Emisión de Positrones
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