Spin coherent quantum transport of electrons between defects in diamond

The nitrogen-vacancy color center in diamond has rapidly emerged as an important solid-state system for quantum information processing. While individual spin registers have been used to implement small-scale diamond quantum computing, the realization of a large-scale device requires development of an on-chip quantum bus for transporting information between distant qubits. Here we propose a method for coherent quantum transport of an electron and its spin state between distant NV centers. Transport is achieved by the implementation of spatial stimulated adiabatic Raman passage through the optical control of the NV center charge states and the confined conduction states of a diamond nanostructure. Our models show that for two NV centers in a diamond nanowire, high fidelity transport can be achieved over distances of order hundreds of nanometres in timescales of order hundreds of nanoseconds. Spatial adiabatic passage is therefore a promising option for realizing an on-chip spin quantum bus

IMPACT OF ACTIVE COMPOUNDS ISOLATED FROM BANANA (MUSA SP. VAR. NANJANGUD RASABALE) FLOWER AND PSEUDOSTEM TOWARDS CYTOPROTECTIVE AND DNA PROTECTION ACTIVITIES

Objective: The present study was designed to evaluate for cytoprotective and DNA protective properties of the compounds isolated from ethanol extract of banana flower (EF) and ethanol extract of banana pseudostem (EE).Methods: The four active compounds viz., umbelliferone (C1) andlupeol (C2) from EF and stigmasterol (C3) and β-sitosterol (C4) from EE were isolated by activity-guided repeated fractionation through silica gel column chromatography. The isolated compounds were evaluated for cytoprotective on erythrocytes and pTZ57R/T plasmid DNA protection against hydroxyl radicals.Results: The study revealed that the compounds (C1-C4) at a concentration of 1 mg/ml exhibited 90% protection on erythrocytes membrane oxidation and also protect the pTZ57R/T plasmid DNA damage induced by hydroxyl radicals.Conclusion: These results endorse an insight for a strong chemical basis to the alleged beneï¬cial role of EF and EE in reducing oxidative stress conditions.Â

Global Retinoblastoma Presentation and Analysis by National Income Level.

Importance: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. Objectives: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. Design, Setting, and Participants: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. Main Outcomes and Measures: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. Results: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis was more common in LMICs even after adjusting for age (odds ratio for low-income countries vs upper-middle-income countries and HICs, 17.92 [95% CI, 12.94-24.80], and for lower-middle-income countries vs upper-middle-income countries and HICs, 5.74 [95% CI, 4.30-7.68]). Conclusions and Relevance: This study is estimated to have included more than half of all new retinoblastoma cases worldwide in 2017. Children from LMICs, where the main global retinoblastoma burden lies, presented at an older age with more advanced disease and demonstrated a smaller proportion of familial history of retinoblastoma, likely because many do not reach a childbearing age. Given that retinoblastoma is curable, these data are concerning and mandate intervention at national and international levels. Further studies are needed to investigate factors, other than age at presentation, that may be associated with advanced disease in LMICs

The global retinoblastoma outcome study : a prospective, cluster-based analysis of 4064 patients from 149 countries

DATA SHARING : The study data will become available online once all analyses are complete.BACKGROUND : Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival. METHODS : We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1, 2017, and Dec 31, 2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models. FINDINGS : The cohort included 4064 children from 149 countries. The median age at diagnosis was 23·2 months (IQR 11·0–36·5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0·8%) of 636 children from high-income countries, 55 (5·4%) of 1027 children from upper-middle-income countries, 342 (19·7%) of 1738 children from lower-middle-income countries, and 196 (42·9%) of 457 children from low-income countries. Enucleation surgery was available for all children and intravenous chemotherapy was available for 4014 (98·8%) of 4064 children. The 3-year survival rate was 99·5% (95% CI 98·8–100·0) for children from high-income countries, 91·2% (89·5–93·0) for children from upper-middle-income countries, 80·3% (78·3–82·3) for children from lower-middle-income countries, and 57·3% (52·1-63·0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16·67; 95% CI 4·76–50·00), cT4 advanced tumour compared to cT1 (8·98; 4·44–18·18), and older age at diagnosis in children up to 3 years (1·38 per year; 1·23–1·56). For children aged 3–7 years, the mortality risk decreased slightly (p=0·0104 for the change in slope). INTERPRETATION : This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes.The Queen Elizabeth Diamond Jubilee Trust and the Wellcome Trust.https://www.thelancet.com/journals/langlo/homeam2023Paediatrics and Child Healt

Triangular cyclic rotaxanes: Size, fluctuations, and switching properties

We examine one of the simplest cyclic rotaxanes - a molecule made from three rods with variable length between 0 and L. This [3]rotaxane, unlike a traditional molecule, shows significant size and shape fluctuations. We quantify these using a number of different measures. In particular, we show that the average angles are 100°,52°, and 28° and the most populated lengths lie at L,2L/3, and L/3. The triangles are usually obtuse. We discuss the area allowed within the triangle for inclusion compounds. Inspired by the linear rotaxane switches, we also consider the statistical mechanics of switching when stations with attractive interactions promote small-cycle areas

Room-temperature quantum emitter arrays in hexagonal boron nitride

We demonstrate deterministic formation of quantum emitter arrays in hexagonal Boron Nitride (hBN) at room temperature. The emitters are localized around the location of high strain provided by the nanopillar substrate.This work is supported by the CUNY ASRC Nanofabrication Fellowship program, NSF CREST IDEALS center, NSF MRSEC program (DMR-1420634) and the NSF EFRI 2-DARE program (EFMA -1542863) and was partially carried out at the CUNY ASRC NanoFabrication Facilit

Formation of quantum emitter arrays in hexagonal Boron Nitride at room temperature

Room temperature quantum emitter arrays are created in hexagonal Boron Nitride (hBN) by deterministic activation via strain engineering on a nanopillar substrate. Emitters are localized at pillar edges where the hBN film undergoes maximum strain

Spin coherent quantum transport of electrons between defects in diamond

The nitrogen-vacancy (NV) color center in diamond has rapidly emerged as an important solid-state system for quantum information processing. Whereas individual spin registers have been used to implement small-scale diamond quantum computing, the realization of a large-scale device requires the development of an on-chip quantum bus for transporting information between distant qubits. Here, we propose a method for coherent quantum transport of an electron and its spin state between distant NV centers. Transport is achieved by the implementation of spatial stimulated adiabatic Raman passage through the optical control of the NV center charge states and the confined conduction states of a diamond nanostructure. Our models show that, for two NV centers in a diamond nanowire, high-fidelity transport can be achieved over distances of order hundreds of nanometers in timescales of order hundreds of nanoseconds. Spatial adiabatic passage is therefore a promising option for realizing an on-chip spin quantum bus

Near-deterministic activation of room-temperature quantum emitters in hexagonal boron nitride

Applications of quantum science to computing, cryptography, and imaging are on their way to becoming key next-generation technologies. Owing to the high-speed transmission and exceptional noise properties of photons, quantum photonic architectures are likely to play a central role. A long-standing hurdle, however, has been the realization of robust, device-compatible single-photon sources that can be activated and controlled on demand. Here we demonstrate large arrays of room-temperature quantum emitters in two-dimensional hexagonal boron nitride (hBN). The large energy gap inherent to this van der Waals material stabilizes the emitters at room temperature within nanoscale regions defined by substrate-induced deformation of few-atomic-layer hBN. Combining analytical and numerical modeling, we show that emitter activation is the result of carrier trapping in deformation potential wells localized near the points where the hBN film reaches the highest curvature. Through the control of pillar geometry, we demonstrate an average of ~2 emitters per site for the smallest pillars (75 nm diameter). These findings set the stage for realizing arrays of room-temperature single-photon sources through the combined control of strain and external electrostatic potentials.N. P. acknowledges support from CREST IDEALS (NSF 1547830). Z. S., M. D., and V. M. M. acknowledge support from the National Science Foundation (USA) through the EFRI 2DARE program. H. J. and C. A. M. acknowledge support from the National Science Foundation (USA) through grants 1619896 and 1401632, and from the Research Corporation through a FRED award. M. W. D. acknowledges support from the Australian Research Council (DE170100169). A. A. acknowledges support from the Research Council of Lithuania