19 research outputs found

    Experimental validation of bulk-graphene as a thermoelectric generator

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    Quest for alternate energy sources is the core of most of the research activities these days. No matter how small or large amount of energy can be produced by utilizing the non-conventional techniques and sources, every bit of innovation can reshape the future of energy. In this work, experimental analysis of the thermoelectric (TE) properties of bulk-graphene in the temperature range of (303 to 363) K is presented. Graphene powder was pressed to form a pellet which was used to fabricate the TE device. The effects of temperature on the Seebeck coefficient, electrical and thermal conductivities, and the dimensionless figure of merit (FOM) were measured. The increasing value of the Seebeck coefficient (thermopower) with temperature is indicant of the metallic behavior. Additionally, the observed thermopower (TEP) is positive, which shows that the majority charge carriers are holes and peaked to a value of 56 μV K-1 at 363 K. The thermopower of the pellet is four times larger than the previously reported values for single layer graphene (SLG) and few layer graphene (FLG). In addition to this, low values of the thermal conductivity were observed for the pellet which is one of the requirements of a good TE material. Besides this, an upward trend is observed with increasing temperature for FOM, which attains a peak value of 0.0016 at 363 K, which is almost ten times that of the previously reported values

    A phase 2 trial of consolidation pembrolizumab following concurrent chemoradiation for patients with unresectable stage III non–small cell lung cancer: Hoosier Cancer Research Network LUN 14-179

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    Background Five-year overall survival (OS) for patients with unresectable stage III non–small cell lung cancer (NSCLC) is poor. Until recently, a standard of care was concurrent chemoradiation alone. Patients with metastatic NSCLC treated with anti–programmed death 1 antibodies have demonstrated improved OS. This trial evaluated pembrolizumab as consolidation therapy after concurrent chemoradiation in patients with unresectable stage III disease. Methods Patients with unresectable stage III NSCLC received concurrent chemoradiation with cisplatin and etoposide, cisplatin and pemetrexed, or carboplatin and paclitaxel and 59.4 to 66.6 Gy of radiation. Patients with nonprogression of disease were enrolled and received pembrolizumab (200 mg intravenously every 3 weeks for up to 12 months). The primary endpoint was the time to metastatic disease or death (TMDD). Secondary endpoints included progression-free survival (PFS) and OS. Results The median follow-up for 93 patients (92 for efficacy) was 32.2 months (range, 1.2-46.6 months). The median TMDD was 30.7 months (95% confidence interval [CI], 18.7 months to not reached), which was significantly longer than the historical control of 12 months (P < .0001). The median PFS was 18.7 months (95% CI, 12.4-33.8 months), and the median OS was 35.8 months (95% CI, 24.2 months to not reached). The 1-, 2-, and 3-year OS estimates were 81.2%, 62.0%, and 48.5%, respectively. Forty patients (43.5%) completed 12 months of treatment (median number of cycles, 13.5). Symptomatic pneumonitis (grade 2 or higher) was noted in 16 patients (17.2%); these cases included 4 grade 3 events (4.3%), 1 grade 4 event (1.1%), and 1 grade 5 event (1.1%). Conclusions Consolidation pembrolizumab after concurrent chemoradiation improves TMDD, PFS, and OS in comparison with historical controls of chemoradiation alone. Rates of grade 3 to 5 pneumonitis were similar to those reported with chemoradiation alone

    Global Retinoblastoma Presentation and Analysis by National Income Level.

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    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

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    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

    Physical and mechanical characterization of sand replaced stone dust concrete

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    In this research work, physical, chemical, morphological, and mechanical behavior as partial replacement of fine aggregate in concrete. Stone dust was acquired from three different sources i.e. Nowshera, Dara, and Besai, while concrete was kept at a ratio of 1:2:4 and water to cement ratio at 0.5 as per ASTM standards for considerable workability. The compressive strength, ultrasonic pulse velocity (UPV), its correlation, density, durability test, x-ray fluorescence (XRF) analysis, and Scanning electron microscopy was carried out. Compressive strength at curing ages of 7, 14, and 28 days with 20%, 30%, and 40% replacement of sand was incorporated in concrete. The results indicated a slight increase in compressive strength at 20% replacement level for the Besai Concrete (BC), Nowshera Concrete (NC), and Dara Concrete (DC). For durability analysis; Rapid Chloride Permeability Test (RCPT) carried out on hardened stone dust-based concrete shows that with the addition of stone dust the voids between fine and coarse aggregates are filled up, less charge will pass, and ultimately durability is increased as per ASTM C 1202. The chemical composition of the stone dust samples, through XRF analysis, indicated that Silica dioxide (SiO2) compounds present in (NC), (DC), and (BC) were 13.34%, 12.339% & 11.593% respectively. The maximum compressive strength development in NC was possibly due to the presence of SiO _2 compound in excess quantity in Nowshera stone dust as compared to other samples tested. Hence it can be recommended that locally available stone dust in Peshawar and its surrounding are suitable for a maximum of 40% replacement level
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