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1.
J Org Chem ; 89(5): 3390-3402, 2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38377557

RESUMO

The introduction of alkyne moieties into peptides remains in demand as it represents a promising approach for further structural diversification of peptides. Herein, we describe the Pd(II)-catalyzed C(sp3)-H alkynylation of Ala-Asn-embedded di- and tripeptides using Asn as the endogenous lead group. In addition, a key building block for the glycopeptide Tyc4PG-14 and Tyc4PG-15 was produced by our methodology.


Assuntos
Alanina , Alcinos , Glicopeptídeos , Catálise
2.
Eur Spine J ; 33(5): 1868-1898, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38407614

RESUMO

PURPOSE: As an important treatment for spinal metastasis, surgery has strict applicable conditions. Although various organizations have formulated different guidelines on surgical treatment for spinal metastasis (SM), there are certain differences in the content, standardization and quality of the guidelines and it is necessary to make a critical appraisal of them. We aim to systematically review and appraise the current guidelines on surgical treatments of SM and summarize the related recommendations with the quality evaluation of supporting evidence, as to provide a reference for the standardization of surgical treatment plans, and help clinical front-line medical workers can make safe and effective clinical decisions faster. METHODS: We searched Pubmed, Web of Science, and Embase for three major databases and online guideline databases. According to certain inclusion and exclusion criteria, the latest guidelines on the surgical treatment of SM were sorted out. AGREE II was used to evaluated the guideline's quality, and we extracted and compared the recommended treatment content of each guideline with evaluating by the evidence-grading scale. RESULTS: Eight guidelines from 2013 to 2019 were included. Seven guidelines are comprehensive guidelines and one related to the reconstructive surgery of SM. Five guidelines were evaluated as "recommended," and three guidelines were evaluated as "recommended with modifications." Regarding the indications of surgery with SM, four guidelines, seven guidelines, seven guidelines, three guidelines and three guidelines recommended surgical treatment for patients with SM with intractable pain, mechanical instability, metastatic epidural spinal cord compression (MESCC), recurrent spinal metastasis (RSM), and survival predication, respectively. Regarding the surgical strategies, three guidelines recommended minimally invasive therapy but had strict indications. Six guidelines and five guidelines recommend palliative surgery and with receiving radiation therapy, respectively. For the aggressive surgery, only one guideline recommended to apply to patients in good general conditions who has isolated symptomatic SM. Regarding the surgical reconstructions, one guideline didn't recommend iliac bone graft and three guidelines recommended PMMA bone cement. CONCLUSION: Most of the guidelines do not provide clear criteria for surgical application and provide more of a basic framework. The level of evidence for these surgical recommendations ranges from LOE B to D, and almost all guidelines recommend vertebroplasty and kyphoplasty, but for palliative and more aggressive surgery, which recommended to personalize specific surgical strategies with multidisciplinary collaboration.


Assuntos
Guias de Prática Clínica como Assunto , Neoplasias da Coluna Vertebral , Humanos , Guias de Prática Clínica como Assunto/normas , Neoplasias da Coluna Vertebral/secundário , Neoplasias da Coluna Vertebral/cirurgia
3.
Angew Chem Int Ed Engl ; 63(44): e202408309, 2024 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-39104033

RESUMO

Advancing the energy-intensive Haber-Bosch process faces significant challenges due to the intrinsic constraints of scaling relations in heterogeneous catalysis. Herein, we reported an approach of bending the "seesaw effect" to regulate the scaling relations over a tailored α-Fe metallic material (α-Fe-110s), realizing highly efficient light-driven thermal catalytic ammonia synthesis with a rate of 1260 µmol gcatalyst -1 h-1 without additional heating. Specifically, the thermal catalytic activity of α-Fe-110s was significantly enhanced by the novel stepped {110} surface, exhibiting a 3.8-fold increase compared to the commercial fused-iron catalyst with promoters at 350 °C. The photo-induced hot electron transfer further accelerates the dinitrogen dissociation and hydrogenation simultaneously, effectively overcoming the limitation of scaling relation over identical sites. Consequently, the ammonia production rate of α-Fe-110s was further enhanced by 30 times at the same temperature with irradiation. This work designs an efficient and sustainable system for ammonia synthesis and provides a novel approach for regulating the scaling relations in heterogeneous catalysis.

4.
Phys Rev Lett ; 131(13): 133601, 2023 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-37831993

RESUMO

Berry curvature is a fundamental element to characterize topological quantum physics, while a full measurement of Berry curvature in momentum space was not reported for topological states. Here we achieve two-dimensional Berry curvature reconstruction in a photonic quantum anomalous Hall system via Hall transport measurement of a momentum-resolved wave packet. Integrating measured Berry curvature over the two-dimensional Brillouin zone, we obtain Chern numbers corresponding to -1 and 0. Further, we identify bulk-boundary correspondence by measuring topology-linked chiral edge states at the boundary. The full topological characterization of photonic Chern bands from Berry curvature, Chern number, and edge transport measurements enables our photonic system to serve as a versatile platform for further in-depth study of novel topological physics.

5.
Lupus ; 32(4): 500-507, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36748829

RESUMO

OBJECTIVE: To accelerate the onset of systemic lupus erythematosus in C57BL/6 mice by injecting cadmium chloride nanoemulsion and shorten the traditional modeling time. METHODS: Pristane cadmium chloride nanoemulsion was prepared, and 66 C57BL/6 mice were randomly divided into four groups. The pristane group was intraperitoneally injected with 0.6 mL of pristane blank nanoemulsion, the model group was injected with 0.6 mL of pristane cadmium chloride nanoemulsion, the Cadmium chloride control group was injected with 0.6 mL of cadmium chloride nanoemulsion, and the control group was injected with the same amount of 0.9% sodium chloride solution. Urine protein content, anti-dsDNA antibody content, Th1 cell/Th2 cell ratio, and kidney staining were detected in each group. RESULTS: The model group began to develop disease in the 4th week, the anti-dsDNA antibody level reached 566.71 ± 1.44 ng/L, and the proteinuria reached 245.38 ± 30.54 ng/mL. The model group showed an onset at least 5 weeks earlier than that in the pristane group. There was no significant difference in anti-dsDNA antibody content between Cadmium chloride control group and blank group. At the 12th week, the Th1/Th2 cell ratio in the model group significantly decreased, and the pathological changes in the kidneys were consistent with the typical manifestations of lupus in mouse models. CONCLUSION: These results suggest that cadmium chloride promotes earlier onset of pristane-induced systemic lupus erythematosus in a C57BL/6 mouse model.


Assuntos
Lúpus Eritematoso Sistêmico , Camundongos , Animais , Cloreto de Cádmio/toxicidade , Camundongos Endogâmicos C57BL , Terpenos/efeitos adversos , Modelos Animais de Doenças , Camundongos Endogâmicos BALB C
6.
Cell Mol Biol (Noisy-le-grand) ; 69(15): 21-25, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38279503

RESUMO

This study was to analyze the correlations of IL-1ß and vitamin D (VitD) with chronic obstructive pulmonary disease assessment test (CAT) score in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). For this purpose, a total of 65 patients with chronic obstructive pulmonary disease (COPD) treated in our hospital between June 2020 and June 2022 were enrolled and assigned to a research group, and 40 healthy individuals who underwent physical examination in our hospital over the same time spanning were enrolled into the control group. The 65 COPD patients were further grouped into a stability group (30 cases) and an exacerbation group (35 cases). The two groups were compared in the levels of 25-hydroxyvitamin D (25(OH)D), interleukin-1ß (IL-1ß) and blood gas indexes (arterial carbon dioxide partial pressure (PaCO2) and arterial partial pressure of oxygen (PaO2). The modified Medical Research Council Dyspnea Scale (mMRC) and the CAT were adopted for evaluation of the stability group and exacerbation group. The correlations of IL-1ß and 25(OH)D with mMRC and CAT scores were analyzed. The diagnostic value of IL-1ß and VitD in patients in different stages was analyzed through receiver operating characteristic (ROC) curves. Results showed that the control group showed greatly lower IL-1ß and PaCO2 levels and higher 25(OH)D and PaO2 levels than the research group (all P<0.05). The stability group got greatly lower mMRC and CAT scores than the exacerbation group (both P<0.05). IL-1ß had positive correlations with mMRC and CAT scores, while 25(OH)D had negative correlations with them (P<0.05). According to ROC curve-based analysis, IL-1ß and 25(OH)D had areas under the curves of 0.814 and 0.583, respectively, in diagnosing the acute exacerbation period, and had specificities of 56.67% and 43.33%, respectively and sensitivities of 97.14% and 74.29%, respectively. In conclusion, patients with COPD have increased IL-1 ß and VitD deficiency, so VitD can be properly supplemented during treatment, and the levels of inflammatory factors should be paid close attention to at all times. IL-1 ß and VitD can be regarded as novel ideas for the diagnosis and treatment of COPD, which may further improve the effect of COPD prevention and treatment.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Humanos , Interleucina-1beta , Oxigênio , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Vitamina D , Vitaminas
7.
Nutr Neurosci ; : 1-17, 2023 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-37950873

RESUMO

BACKGROUND: To comprehensively assess the neurologic recovery potential of chondroitinase ABC (ChABC) in rats after spinal cord injury (SCI). METHODS: The PubMed, Embase, ScienceDirect, Web of Science, and China National Knowledge Infrastructure databases were searched for animal experiments that evaluated the use of ChABC in the treatment of SCI up to November 2022. Studies reporting neurological function using the Basso, Beattie, and Bresnahan (BBB) scale, as well as assessments of cavity area, lesion area, and glial fibrillary acidic protein (GFAP) levels, were included in the analysis. RESULTS: A total of 46 studies were ultimately selected for inclusion. The results of the study showed that rats with SCI that received ChABC therapy exhibited a significant improvement in locomotor function after 7 days compared with controls (32 studies, weighted mean difference (WMD) = 0.58, [0.33, 0.83], p < 0.00001). Furthermore, the benefits of ChABC therapy were maintained for up to 28 days according to BBB scale. The lesion area was reduced by ChABC (5 studies, WMD = -20.94, [-28.42, -13.46], p < 0.00001). Meanwhile, GFAP levels were reduced in the ChABC treatment group (8 studies, WMD = -29.15, [-41.57, -16.72], p < 0.00001). Cavity area is not statistically significant. The subgroup analysis recommended that a single injection of 10 µL (8 studies, WMD = 2.82, [1.99, 3.65], p < 0.00001) or 20 U/mL (4 studies, WMD = 2.21, [0.73, 3.70], p = 0.003) had a better effect on improving the function. The funnel plot of the BBB scale was found to be essentially symmetrical, indicating a low risk of publication bias. CONCLUSIONS: This systematic review and meta-analysis has indicated that ChABC could improve functional recovery in rats after SCI.

8.
BMC Ophthalmol ; 23(1): 446, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37932670

RESUMO

INTRODUCTION: Blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES) is a rare genetic disease with diverse ocular malformations. This study aimed to investigate the disease-causing gene in members of a BPES pedigree presenting with the rare features of anisometropia, unilateral pathologic myopia (PM), and congenital cataracts. METHODS: The related BPES patients underwent a comprehensive ocular examination. Next, whole-exome sequencing (WES) was performed to screen for the disease-causing genetic variants. A step-wise variant filtering was performed to select candidate variants combined with the annotation of the variant's pathogenicity, which was assessed using several bioinformatic approaches. Co-segregation analysis and Sanger sequencing were then conducted to validate the candidate variant. RESULTS: The variant c.672_701dup in FOXL2 was identified to be the disease-causing variant in this rare BPES family. Combined with clinical manifestations, the two affected individuals were diagnosed with type II BPES. CONCLUSION: This study uncovered the variant c.672_701dup in FOXL2 as a disease causal variant in a rare-presenting BPES family with anisometropia, unilateral pathogenic myopia, and/or congenital cataracts, thus expanding the phenotypic spectrum of FOXL2.


Assuntos
Anisometropia , Blefarofimose , Catarata , Miopia , Humanos , Mutação , Sequenciamento do Exoma , Linhagem , Síndrome , Proteína Forkhead Box L2/genética
9.
Eur Spine J ; 32(1): 228-243, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36372842

RESUMO

PURPOSE: Lung cancer is one of the most common malignant tumors. Most patients develop spinal metastases during the course of cancer and suffer skeletal-related events. Currently, no consensus has been reached on the prognostic factors in patients undergoing surgeries. This study aimed to answer two questions: (1) what are the effects of surgical intervention, and (2) what are the factors associated with postoperative survival. METHODS: Searches were performed on electronic databases including PubMed, Ovid/MEDLINE, Cochrane, and Scopus for articles published before February of 2022, involving the survival factors of patients with spinal metastasis. Multiple data items were considered, such as baseline demographics, surgical details, clinical outcome, and prognostic factors. The analysis was performed in Review Manager (RevMan) 5.5. The prognostic factors of survival were analyzed with univariate and multivariate cox regression analysis. RESULTS: Finally, 14 studies with 813 patients were identified. Their 6, 12, and 24 months survival rates ranged from 18 to 58%, 18 to 22.4%, and 0 to 58.5%, respectively. The pooled hazard ratio of preoperative ambulatory status and the number of involved vertebrae demonstrated statistical significance, while no significant prognostic effect on the overall survival was found for targeted therapy, visceral metastases, chemotherapy, radiotherapy, or postoperative ambulatory status. CONCLUSION: Overall, surgical intervention could achieve significant pain relief and neurological function improvements. For patients receiving surgery for spinal metastasis from lung cancer, preoperative ambulatory status and the number of involved vertebrae were significant prognostic factors associated with their survival.


Assuntos
Neoplasias Pulmonares , Neoplasias da Coluna Vertebral , Humanos , Prognóstico , Neoplasias da Coluna Vertebral/secundário , Neoplasias Pulmonares/cirurgia , Coluna Vertebral/patologia , Análise Multivariada , Estudos Retrospectivos
10.
Psychogeriatrics ; 23(5): 864-875, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37464888

RESUMO

BACKGROUND: Post-stroke depression (PSD) as one of the most common neuropsychiatric disorders after a stroke and is caused by many factors. However, the relationships among different factors and their potential contributions to PSD remain unclear. METHODS: Two hundred and seventy-six patients were recruited into this study. The general information questionnaire, the Patient Health Questionnaire-9, the Perceived Social Support Scale, the Family Assessment Device, the General Well-Being Scale, the Barthel Index, and the modified Rankin Scale were used to assess the condition of patients. Subsequently, we identify the main causes associated with the PSD and then performed a path analysis to clarify the direct, indirect and total effects among the variables. RESULTS: We found that age, stroke with coronary heart disease, neurological function, family function, social support, and general well-being had a significant impact on PSD (P < 0.05). Of these, neurological function had the largest total effect on PSD (ß = 0.451), social support contributed the most as a direct effect (ß = -0.306), and family function showed the largest indirect effect (ß = -0.264). CONCLUSION: Individual, disease, and social-psychological factors all contributed to the development of PSD. We should pay more attention to comprehensive assessment, especially for those with poor neurological function, and lacking family or social support. In addition, it would be preferable to provide them with necessary support and care strategies to reduce the incidence of PSD.


Assuntos
Depressão , Acidente Vascular Cerebral , Humanos , Depressão/diagnóstico , Depressão/etiologia , Depressão/epidemiologia , Fatores de Risco , Acidente Vascular Cerebral/psicologia , Inquéritos e Questionários
11.
Phys Rev Lett ; 129(4): 046401, 2022 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-35939012

RESUMO

Topological insulators host topology-linked boundary states, whose spin and charge degrees of freedom could be exploited to design topological devices with enhanced functionality. We experimentally observe that dissipationless chiral edge states in a spin-orbit coupled anomalous Floquet topological phase exhibit topological spin texture on boundaries, realized via a two-dimensional quantum walk. Our experiment shows that, for a walker traveling around a closed loop along the boundary in real space, its spin evolves and winds through a great circle on the Bloch sphere, which implies that edge-spin texture has nontrivial winding. This topological spin winding is protected by a chiral-like symmetry emerging for the low-energy Hamiltonian. Our experiment confirms that two-dimensional anomalous Floquet topological systems exhibit topological spin texture on the boundary, which could inspire novel topology-based spintronic phenomena and devices.

12.
Int J Mol Sci ; 23(23)2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36499548

RESUMO

Construction of the tunable oxygen vacancies (OVs) is widely utilized to accelerate molecular oxygen activation for boosting photocatalytic performance. Herein, the in-situ introduction of OVs on Bi2MoO6 was accomplished using a calcination treatment in an H2/Ar atmosphere. The introduced OVs can not only facilitate carrier separation, but also strengthen the exciton effect, which accelerates singlet oxygen generation through the energy transfer process. Superior carrier separation and abundant singlet oxygen played a crucial role in favoring photocatalytic NaPCP degradation. The optimal BMO-001-300 sample exhibited the fastest NaPCP degradation rate of 0.033 min-1, about 3.8 times higher than that of the pristine Bi2MoO6. NaPCP was effectively degraded and mineralized mainly through dechlorination, dehydroxylation and benzene ring opening. The present work will shed light on the construction and roles of OVs in semiconductor-based photocatalysis and provide a novel insight into ROS-mediated photocatalytic degradation.


Assuntos
Pentaclorofenol , Oxigênio Singlete , Oxigênio , Sódio
13.
Angew Chem Int Ed Engl ; 61(24): e202201610, 2022 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-35274423

RESUMO

Understanding the electrode/electrolyte interface is crucial for optimizing electrocatalytic performances. Here, we demonstrate that the nature of alkali metal cations can profoundly impact the oxygen evolution activity of surface-mounted metal-organic framework (SURMOF) derived electrocatalysts, which are based on NiFe(OOH). In situ Raman spectroscopy results show that Raman shifts of the Ni-O bending vibration are inversely proportional to the mass activities from Cs+ to Li+ . Particularly, a laser-induced current transient technique was introduced to study the cation-dependent electric double layer properties and their effects on the activity. The catalytic trend appeared to be closely related to the potential of maximum entropy of the system, suggesting a strong cation impact on the interfacial water layer structure. Our results highlight how the electrolyte composition can be used to maximize the performance of SURMOF derivatives toward electrochemical water splitting.

14.
Chemistry ; 27(39): 10016-10020, 2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34050569

RESUMO

The influence of electrolyte pH, the presence of alkali metal cations (Na+ , K+ ), and the presence of O2 on the interfacial water structure of polycrystalline gold electrodes has been experimentally studied in detail. The potential of maximum entropy (PME) was determined by the laser-induced current transient (LICT) technique. Our results demonstrate that increasing the electrolyte pH and introducing O2 shift the PME to more positive potentials. Interestingly, the PME exhibits a higher sensitivity to the pH change in the presence of K+ than Na+ . Altering the pH of the K2 SO4 solution from 4 to 6 can cause a drastic shift in the PME. These findings reveal that, for example, K2 SO4 and Na2 SO4 cannot be considered as equal supporting electrolytes: it is not a viable assumption. This can likely be extrapolated to other common "inert" supporting electrolytes. Beyond this, knowledge about the near-ideal electrolyte composition can be used to optimize electrochemical devices such as electrolyzers, fuel cells, batteries, and supercapacitors.

15.
Nano Lett ; 20(1): 152-157, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31841348

RESUMO

We demonstrate fourth-order quantum beat between sunlight and single photons from a quantum dot. With a fast time-resolved detection system, we observed high-visibility quantum beat between the independent photons of different frequencies from the two astronomically separated light sources. The temporal dynamics of the beat oscillation indicate the coherent behavior of the interfering photons, and the raw visibility of two-photon interference shows violation of the classical limit with a frequency mismatch of three-times the line width.

16.
Gene Ther ; 27(3-4): 113-126, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31562386

RESUMO

We aimed to investigate how estrogen (ES) is implicated in the pathogenesis of pulmonary arterial hypertension (PAH) potentially by reducing the extent of vascular remodeling in females. HE assay, Western Blot, IHC, and real-time PCR were carried out to observe the role of ES in regulating miR-133a expression and the levels of MYOSLID, SRF, CTGF, and vascular remodeling in rats. In addition, MTT assay and flow cytometry were utilized to observe how ES affects cell proliferation and cell cycle in PAH. Moreover, luciferase assays were carried out to clarity the regulatory relationship between miR-133a and its downstream targets. ES administration relieved the deregulation of miR-133a, MYOSLID, SRF, and CTGF in PAH rats. In addition, ES also reduced the thickening of blood vessels in PAH rats. ES could activate miR-133a promoter and arrest the cells in the G0/G1 cycle, thus dose-dependently suppressing the proliferation of cells. In addition, the presence of ES, MYOSLID siRNA, or miR-133a precursor all altered the expression of MYOSLID, SP1, SRF, and CTGF, thus establishing a molecular signaling pathway among these factors. Furthermore, miR-133a could bind to SP1, MYOSLID, SRF, and CTGF to reduce their expression. Moreover, SRF was proved to function as an activator of miR-133a promoter. Two feedback loops were established in this study: a negative feedback loop between SRF and miR-133a, and a positive loop among miR-133a/SRF/MLK1/MYOSLID. ES treatment upregulates miR-133a expression and reduces the incidence of PAH and vascular remodeling.


Assuntos
Estrogênios/farmacologia , Hipertensão Pulmonar/prevenção & controle , MicroRNAs/metabolismo , Transdução de Sinais , Animais , Vasos Sanguíneos/efeitos dos fármacos , Vasos Sanguíneos/metabolismo , Vasos Sanguíneos/patologia , Proliferação de Células , Células Cultivadas , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Estrogênios/uso terapêutico , Feminino , Hipertensão Pulmonar/tratamento farmacológico , MicroRNAs/genética , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Ratos , Ratos Wistar , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Remodelação Vascular/efeitos dos fármacos
17.
Phys Rev Lett ; 125(15): 153601, 2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33095635

RESUMO

Intensity squeezing-i.e., photon number fluctuations below the shot-noise limit-is a fundamental aspect of quantum optics and has wide applications in quantum metrology. It was predicted in 1979 that intensity squeezing could be observed in resonance fluorescence from a two-level quantum system. However, its experimental observation in solid states was hindered by inefficiencies in generating, collecting, and detecting resonance fluorescence. Here, we report the intensity squeezing in a single-mode fiber-coupled resonance fluorescence single-photon source based on a quantum dot-micropillar system. We detect pulsed single-photon streams with 22.6% system efficiency, which show sub-shot-noise intensity fluctuation with an intensity squeezing of 0.59 dB. We estimate a corrected squeezing of 3.29 dB at the first lens. The observed intensity squeezing provides the last piece of the fundamental picture of resonance fluorescence, which can be used as a new standard for optical radiation and in scalable quantum metrology with indistinguishable single photons.

18.
Angew Chem Int Ed Engl ; 59(27): 10934-10938, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32142192

RESUMO

Herein, we demonstrate an easy way to improve the hydrogen evolution reaction (HER) activity of Pt electrodes in alkaline media by introducing Ni-Fe clusters. As a result, the overpotential needed to achieve a current density of 10 mA cm-2 in H2 -saturated 0.1 m KOH is reduced for the model single-crystal electrodes down to about 70 mV. To our knowledge, these modified electrodes outperform any other reported electrocatalysts tested under similar conditions. Moreover, the influence of 1) Ni to Fe ratio, 2) cluster coverage, and 3) the nature of the alkali-metal cations present in the electrolyte on the HER activity has been investigated. The observed catalytic performance likely originates from both the improved water dissociation at the Ni-Fe clusters and the subsequent optimal hydrogen adsorption and recombination at Pt atoms present at the Ni-Fe/Pt boundary.

19.
Phys Rev Lett ; 122(11): 113602, 2019 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-30951338

RESUMO

An outstanding goal in quantum optics and scalable photonic quantum technology is to develop a source that each time emits one and only one entangled photon pair with simultaneously high entanglement fidelity, extraction efficiency, and photon indistinguishability. By coherent two-photon excitation of a single InGaAs quantum dot coupled to a circular Bragg grating bull's-eye cavity with a broadband high Purcell factor of up to 11.3, we generate entangled photon pairs with a state fidelity of 0.90(1), pair generation rate of 0.59(1), pair extraction efficiency of 0.62(6), and photon indistinguishability of 0.90(1) simultaneously. Our work will open up many applications in high-efficiency multiphoton experiments and solid-state quantum repeaters.

20.
Phys Rev Lett ; 123(25): 250503, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31922765

RESUMO

Quantum computing experiments are moving into a new realm of increasing size and complexity, with the short-term goal of demonstrating an advantage over classical computers. Boson sampling is a promising platform for such a goal; however, the number of detected single photons is up to five so far, limiting these small-scale implementations to a proof-of-principle stage. Here, we develop solid-state sources of highly efficient, pure, and indistinguishable single photons and 3D integration of ultralow-loss optical circuits. We perform experiments with 20 pure single photons fed into a 60-mode interferometer. In the output, we detect up to 14 photons and sample over Hilbert spaces with a size up to 3.7×10^{14}, over 10 orders of magnitude larger than all previous experiments, which for the first time enters into a genuine sampling regime where it becomes impossible to exhaust all possible output combinations. The results are validated against distinguishable samplers and uniform samplers with a confidence level of 99.9%.

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