937 research outputs found

    Building Innovation System for the Diffusion of Renewable EnergyTechnology: Practices in Ethiopia and Bangladesh

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    AbstractThe diffusion of renewable energy technologies (RETs) has been progressing very slowly in global scope, particularly in developing countries where the diffusion challenges for renewable are greater. Among potential actors in the promotion and diffusion of rural-based renewable energy innovations, NGOs and NPOs have been mentioned as promising actors. However, empirical studies that show the role of the actors and the way they can besystem builders by diffusing existing technologies have been very rare. This paper discusses the practices of an NGO in Ethiopia (Solar Energy Foundation) and an NPO in Bangladesh (Grameen Shakti) and showshowlocal technological innovation systems can be built bykey actors in the context of developing countries. The studysheds light on the process of system building for accelerated diffusion of RETs in the context of developing countries. Using a theoretical framework, we compared the approach, technology adoption trend (solar home systems diffusion), and common challenges facing both actors in their respective countries. The two empirical cases which are in different geographical contexts provided lessons on thesimilarities and differences of system building practices and emerging innovation systems for diffusion of RETs in developing countries

    An mHealth Application to Promote Diabetes Self-care Behavior among Medically Underserved Population

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    Diabetes is a chronic illness that causes serious health complications such as kidney failure, limb amputations, and often leads to premature death. Adoption of self-care behavior among diabetes patients is known to improve their health conditions and quality of life. Medically underserved populations (MUP) are disproportionately affected by diabetes. In this research we use a design science approach to develop an mHealth app to promote diabetes self-care behavior among MUPs. Using design theories on behavior change and user-centered design we articulated five key design principles. A mobile app based on these principles and AADE7 self-care behavior framework has been implemented using an Android system. We are currently in the process of evaluating its effectiveness. Our research contributes to the discourse on design for behavior change and illustrates the effectiveness of mHealth apps in promoting healthy lifestyles

    The quest for better outcomes: a randomized controlled trial comparing letrozole versus clomiphene citrate in polycystic ovarian syndrome related infertility

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    Background: Infertility is a widespread concern, particularly among individuals with polycystic ovarian syndrome (PCOS). Clomiphene citrate (CC) has been a primary treatment for PCOS-related infertility, despite suboptimal pregnancy rates. Letrozole, an aromatase inhibitor, presents an alternative with potential advantages for improving pregnancy outcomes. This study aimed to rigorously compare letrozole and CC in the context of PCOS-related infertility, focusing on Bangladeshi women, adopting incremental dosing protocols, and examining endpoints to contribute valuable insights. Methods: A randomized controlled trial was conducted at a tertiary care center in Bangladesh from July 2021 to June 2023. Participants included women aged 18-35 with anovulatory infertility due to PCOS. They were randomized into two groups: letrozole and CC. Treatments were administered following incremental dosing protocols, and outcomes included endometrial thickness, ovulation rate, mono-follicular development, pregnancy rate, and time to pregnancy. Results: Out of 187 patients assessed for eligibility, 102 were enrolled, with 51 in each group. Demographics were comparable between groups. While endometrial thickness did not significantly differ between the groups, letrozole demonstrated a higher rate of mono-follicular development (72.55% versus 50.98%), a significantly higher pregnancy rate (47.06% versus 23.53%), and a shorter time to pregnancy (9.23 weeks versus 11.7 weeks) compared to CC. Conclusions: This study suggests that letrozole may be a preferred option for ovulation induction in PCOS patients due to its superior pregnancy rates and shorter time to pregnancy compared to CC. However, limitations such as a relatively small sample size and variations in dosages should be considered. Further research is needed to validate these findings and address the evolving needs of patients with PCOS-related infertility

    Synthesis and Functional Evaluation of DNA-Assembled Polyamidoamine Dendrimer Clusters for Cancer Cell-Specific Targeting

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    SummaryWe sought to produce dendrimers conjugated to different biofunctional moieties (fluorescein [FITC] and folic acid [FA]), and then link them together using complementary DNA oligonucleotides to produce clustered molecules that target cancer cells that overexpress the high-affinity folate receptor. Amine-terminated, generation 5 polyamidoamine (G5 PAMAM) dendrimers are first partially acetylated and then conjugated with FITC or FA, followed by the covalent attachment of complementary, 5′-phosphate-modified 34-base-long oligonucleotides. Hybridization of these oligonucleotide conjugates led to the self-assembly of the FITC- and FA-conjugated dendrimers. In vitro studies of the DNA-linked dendrimer clusters indicated specific binding to KB cells expressing the folate receptor. Confocal microscopy also showed the internalization of the dendrimer cluster. These results demonstrate the ability to design and produce supramolecular arrays of dendrimers using oligonucleotide bridges. This will also allow for further development of DNA-linked dendrimer clusters as imaging agents and therapeutics

    Electronic Devices Based on Purified Carbon Nanotubes Grown By High Pressure Decomposition of Carbon Monoxide

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    The excellent properties of transistors, wires, and sensors made from single-walled carbon nanotubes (SWNTs) make them promising candidates for use in advanced nanoelectronic systems. Gas-phase growth procedures such as the high pressure decomposition of carbon monoxide (HiPCO) method yield large quantities of small diameter semiconducting SWNTs, which are ideal for use in nanoelectronic circuits. As-grown HiPCO material, however, commonly contains a large fraction of carbonaceous impurities that degrade properties of SWNT devices. Here we demonstrate a purification, deposition, and fabrication process that yields devices consisting of metallic and semiconducting nanotubes with electronic characteristics vastly superior to those of circuits made from raw HiPCO. Source-drain current measurements on the circuits as a function of temperature and backgate voltage are used to quantify the energy gap of semiconducting nanotubes in a field effect transistor geometry. This work demonstrates significant progress towards the goal of producing complex integrated circuits from bulk-grown SWNT material.Comment: 6 pages, 4 figures, to appear in Nature Material

    Microwave breast imaging using compressed sensing approach of iteratively corrected delay multiply and sum beamforming

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    Microwave imaging (MI) is a consistent health monitoring technique that can play a vital role in diagnosing anomalies in the breast. The reliability of biomedical imaging diagnosis is substantially dependent on the imaging algorithm. Widely used delay and sum (DAS)-based diagnosis algorithms suffer from some significant drawbacks. The delay multiply and sum (DMAS) is an improved method and has benefits over DAS in terms of greater contrast and better resolution. However, the main drawback of DMAS is its excessive computational complexity. This paper presents a compressed sensing (CS) approach of iteratively corrected DMAS (CS-ICDMAS) beamforming that reduces the channel calculation and computation time while maintaining image quality. The array setup for acquiring data comprised 16 Vivaldi antennas with a bandwidth of 2.70-11.20 GHz. The power of all the channels was calculated and low power channels were eliminated based on the compression factor. The algorithm involves data-independent techniques that eliminate multiple reflections. This can generate results similar to the uncompressed variants in a significantly lower time which is essential for real-time applications. This paper also investigates the experimental data that prove the enhanced performance of the algorithm. 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This work was supported by Grant NPRP12S-0227-190164 from the Qatar National Research Fund, a member of Qatar Foundation, Doha, Qatar and the internal grant of Qatar University QUST-1-CENG-2021-6 and the claims made herein are solely the responsibility of the authors. This work was supported by the Ministry of Higher Education of Malaysia (MOHE), grant code No. FRGS/1/2018/TK04/UKM/01/3. This work was supported by Grant NPRP12S-0227-190164 from the Qatar National Research Fund, a member of Qatar Foundation, Doha, Qatar and the claims made herein are solely the responsibility of the authors. Open Access funding provided by the Qatar National Library.Scopu

    Metastatic rhabdomyosarcoma of the thyroid gland, a case report

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    The thyroid gland is a known but an unusual site for metastatic tumors from various primary sites. Despite the fact that it is one of the largest vascular organs in the body, clinical and surgical cases have given an incidence of 3 % of secondary malignances of the organ. Nevertheless, thyroid metastases are not an exceptional finding at autopsy, they are encountered in 2 % to 24 % of the patients with malignant neoplasm. Soft tissue sarcomas metastatic to the thyroid are extremely rare as the majority of thyroid metastasis are caused by tumors of the kidneys, lungs, mammary glands, ovaries , and colon or by melanomas. We report a case of 22-years-old woman with right leg rhabdomyosarcoma metastatic to the thyroid gland

    Simulations of Coherent Synchrotron Radiation on Parallel Hybrid GPU/CPU Platform

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    Coherent synchrotron radiation (CSR) is an effect of self-interaction of an electron bunch as it traverses a curved path. It can cause a significant emittance degradation, as well as fragmentation and microbunching. Numerical simulations of the 2D/3D CSR effects have been extremely challenging due to computational bottlenecks associated with calculating retarded potentials via integrating over the history of the bunch. We present a new high-performance 2D, particle-in-cell code which uses massively parallel multicore GPU/GPU platforms to alleviate computational bottlenecks. The code formulates the CSR problem from first principles by using the retarded scalar and vector potentials to compute the self-interaction fields. The speedup due to the parallel implementation on GPU/CPU platforms exceeds three orders of magnitude, thereby bringing a previously intractable problem within reach. The accuracy of the code is verified against analytic 1D solutions (rigid bunch) and semi-analytic 2D solutions for the chirped bunch. Finally, we use the new code in conjunction with a genetic algorithm to optimize the design of a fiducial chicane
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