2,404 research outputs found
The Role of Surface Passivation for Efficient and Photostable PbS Quantum Dot Solar Cells
Peer ReviewedPostprint (author's final draft
Solution-Processed, Solid-State Solar Cells based on Environmentally Friendly AgBiS2 Nanocrystals
Solution-processed inorganic solar cells are a promising low-cost alternative to firstgeneration
solar cells.1,2 Solution processing at low temperatures and the use of nontoxic
and abundant elements can help minimize cost and facilitate regulatory acceptance.
However, until now there has been no material that exhibits all of these features while
demonstrating promising efficiencies. Many of the most promising solution-processed
inorganic solar cells contain toxic elements such as lead or cadmium (perovskites,2,3 PbS,4
CdTe,5,6 CdS(Se)7,8) or scarce elements like tellurium or indium (CdTe, CIGS(Se)/CIS9,10).
Others require high-temperature processes such as selenization or sintering or rely on
vacuum deposition techniques ((Sb2S(Se)3,11–13 SnS,14,15 CZTS(Se)16). Here, we present
AgBiS2 nanocrystals as a novel nontoxic,17 earth-abundant18 material for highperformance,
solution-processed solar cells fabricated in ambient conditions at low
temperatures (≤100°C). The AgBiS2 nanocrystals have favorable properties for solar-cell
applications including a near-ideal bandgap and strong, broad absorption. We
demonstrate a Newport certified power conversion efficiency of 6.3% with no hysteresis
and a remarkably high short-circuit current density of about 22 mA·cm-2 for an active
layer thickness of only ~35 nm.Peer ReviewedPostprint (author's final draft
EvoPrompting: Language Models for Code-Level Neural Architecture Search
Given the recent impressive accomplishments of language models (LMs) for code
generation, we explore the use of LMs as adaptive mutation and crossover
operators for an evolutionary neural architecture search (NAS) algorithm. While
NAS still proves too difficult a task for LMs to succeed at solely through
prompting, we find that the combination of evolutionary prompt engineering with
soft prompt-tuning, a method we term EvoPrompting, consistently finds diverse
and high performing models. We first demonstrate that EvoPrompting is effective
on the computationally efficient MNIST-1D dataset, where EvoPrompting produces
convolutional architecture variants that outperform both those designed by
human experts and naive few-shot prompting in terms of accuracy and model size.
We then apply our method to searching for graph neural networks on the CLRS
Algorithmic Reasoning Benchmark, where EvoPrompting is able to design novel
architectures that outperform current state-of-the-art models on 21 out of 30
algorithmic reasoning tasks while maintaining similar model size. EvoPrompting
is successful at designing accurate and efficient neural network architectures
across a variety of machine learning tasks, while also being general enough for
easy adaptation to other tasks beyond neural network design
Cut points in abcohesive, aposyndetic, and semi-locally connected spaces
In 1941, F. B. Jones introduced aposyndesis, which generalizes the concept of semi-local connectedness defined earlier by G. T. Whyburn (1942), in the study of continuum theory. Using Jones's idea, D. A. John (1993) defined abcohesiveness as a generalization of aposyndesis and studied the A-sets in abcohesive spaces. In this paper, some properties of abcohesive spaces are studied and a number of results by B. Lehman (1976) and Whyburn (1942, 1968) are generalized; sufficient conditions for the existence of two nodal sets are established as well
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Autophagy, cellular aging and age related human diseases
Macroautophagy/autophagy is a conserved degradation system that engulf s i ntracytoplasmic contents, including aggregated proteins and organelles , which is crucial for cellular homeostasis. During aging, cellular factors suggested as the cause of aging have been reported to be associated with prog ressive ly compromised autophagy. D ysfunctional autophagy may contribute to age related diseases such as neurodegenerative disease, cancer, and metabolic syndrome in the elderly Therefore, restoration of impaired autophagy to normal may help to prevent age related disease and extend lifespan and longevit y. Therefore, this review aims to provide an overview of the mechanism s of autophagy machinery underlying cellular aging and the consequent disease Understanding the mechanisms of autophagy can provide potential information to aid therapeutic intervention s in age related diseases.We are grateful for funding from the UK Dementia Research Institute (funded by the MRC, Alzheimer’s Research UK and the Alzheimer’s Society), Roger de Spoelberch Foundation, Alzheimer’s Research UK, The Tau Consortium, Cambridge Centre for Parkinson-Plus, National Institute for Health Research Cambridge Biomedical Research Centre (D.C.R.), and the Korea Health Technology R&D Project (HI14C2173) through the Korea Health Industry Development Institute, funded by the Ministry of Health & Welfare, Republic of Korea (S.Y.C., H. K., and J.E.L)
Sheehan's Syndrome; A Rare Complication of Postpartum Hemorrhage - Case Report and Review of the Literature
Sheehan Syndrome is a Condition that may occur in a woman who bleeds severely during child birth. Severe bleeding during child birth can cause tissue death in the pituitary gland, which may cause the +0 gland to lose its ability to function properly. We reported a case of a 21 year old lady gravida 1 para 1 (alive) who developed Sheehan's syndrome six months after extreme post partum hemorrhage. High level of suspicious was employed based on clinical history and couple with the laboratory blood tests and magnetic resonance Imaging (MRI) findings in arriving at diagnosis of this rare complication of lifethreatening blood loss during or after child birth. We also highlighted the importance of proper medical care in preventing extreme bleeding during child birth, otherwise, Sheehan's syndrome is not preventable.Keywords: Sheehan's Syndrome, Post Partum Hemorrhag
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