Yi Lu

Bio: Yi Lu is an academic researcher from University of Illinois at Urbana–Champaign. The author has contributed to research in topics: Medicine & Aptamer. The author has an hindex of 103, co-authored 628 publications receiving 40883 citations. Previous affiliations of Yi Lu include University of Arizona & Central South University.

A Colorimetric Lead Biosensor Using DNAzyme-Directed Assembly of Gold Nanoparticles

Abstract: A highly sensitive and selective colorimetric lead biosensor based on DNAzyme-directed assembly of gold nanoparticles is reported. It consists of a DNAzyme and its substrate that can hybridize to a 5‘-thio-modified DNA attached to gold nanoparticles. The hybridization brings gold nanoparticles together, resulting in a blue-colored nanoparticle assembly. In the presence of lead, the DNAzyme catalyzes specific hydrolytic cleavage, which prevents the formation of the nanoparticle assembly, resulting in red-colored individual nanoparticles. The detection level can be tuned to several orders of magnitude, from 100 nM to over 200 μM, through addition of an inactive variant of the DNAzyme. The concept developed here can be applied to the design of nucleic acid enzyme/nanoparticle sensors for analytes that are subject to in vitro selection, and thus can significantly expand the scope of nanomaterial applications and provide a novel approach to designing simple colorimetric biosensors.

Preparation of aptamer-linked gold nanoparticle purple aggregates for colorimetric sensing of analytes

Abstract: Aptamers are single-stranded DNA or RNA molecules that can bind target molecules with high affinity and specificity. The conformation of an aptamer usually changes upon binding to its target analyte, and this property has been used in a wide variety of sensing applications, including detection based on fluorescence intensity, polarization, energy transfer, electrochemistry or color change. Colorimetric sensors are particularly important because they minimize or eliminate the necessity of using expensive and complicated instruments. Among the many colorimetric sensing strategies, metallic nanoparticle-based detection is desirable because of the high extinction coefficients and strong distance-dependent optical properties of the nanoparticles. Here, we describe a protocol for the preparation of aptamer-linked gold nanoparticle purple aggregates that undergo fast disassembly into red dispersed nanoparticles upon binding of target analytes. This method has proved to be generally applicable for colorimetric sensing of a broad range of analytes. The time range for the entire protocol is ∼5 d, including synthesis and functionalization of nanoparticles, preparation of nanoparticle aggregates and sensing.

Fast Colorimetric Sensing of Adenosine and Cocaine Based on a General Sensor Design Involving Aptamers and Nanoparticles

Abstract: Aptamers are nucleic acid based binding molecules that are obtained through a combinatorial selection process known as systematic evolution of ligands by exponential enrichment (SELEX). 2] They are emerging as a new class of molecules that can rival antibodies in terms of the broad range of molecules they can selectively bind. In comparison with antibodies, aptamers, particularly DNA aptamers, are relatively easy to obtain, more stable to biodegradation, and less vulnerable to denaturation. Therefore they are prime candidates as sensors in a number of applications, such as environmental monitoring and medical diagnostics. The key challenge to their successful application is transforming the aptamer-binding events into physically detectable signals. To meet the challenge, a number of methods have been developed, most of which involve fluorescence-based detection. Simple colorimetric sensors can eliminate the use of analytical instruments and have attracted much attention recently. For example, organic-dye replacement was employed to design a colorimetric cocaine sensor. However, an appropriate dye has to be found for a designated aptamer, and a waiting time of 12 hours is needed to observe a color change. Cationic conjugated polymers form complexes of different color with aptamers in the presence or absence of a target analyte. A number of colorimetric sensors were made with this method. The high extinction coefficients and distance-dependent optical properties have made metallic nanoparticles very attractive in DNA-related colorimetric assays, such as the detection of DNAwith high sequence selectivity, 22] and the detection of metal ions 24] and other analytes. 17] Recently, aptamer-functionalized gold nanoparticles were employed to detect thrombin. This system took advantage of the fact that each thrombin molecule binds two aptamers, so nanoparticles

Reining in the outliers in map-reduce clusters using Mantri

Abstract: Experience froman operational Map-Reduce cluster reveals that outliers significantly prolong job completion. The causes for outliers include run-time contention for processor, memory and other resources, disk failures, varying bandwidth and congestion along network paths and, imbalance in task workload. We present Mantri, a system that monitors tasks and culls outliers using cause- and resource-aware techniques. Mantri's strategies include restarting outliers, network-aware placement of tasks and protecting outputs of valuable tasks. Using real-time progress reports, Mantri detects and acts on outliers early in their lifetime. Early action frees up resources that can be used by subsequent tasks and expedites the job overall. Acting based on the causes and the resource and opportunity cost of actions lets Mantri improve over prior work that only duplicates the laggards. Deployment in Bing's production clusters and trace-driven simulations show that Mantri improves job completion times by 32%.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Gold nanoparticles: assembly, supramolecular chemistry, quantum-size-related properties, and applications toward biology, catalysis, and nanotechnology.

Abstract: Although gold is the subject of one of the most ancient themes of investigation in science, its renaissance now leads to an exponentially increasing number of publications, especially in the context of emerging nanoscience and nanotechnology with nanoparticles and self-assembled monolayers (SAMs). We will limit the present review to gold nanoparticles (AuNPs), also called gold colloids. AuNPs are the most stable metal nanoparticles, and they present fascinating aspects such as their assembly of multiple types involving materials science, the behavior of the individual particles, size-related electronic, magnetic and optical properties (quantum size effect), and their applications to catalysis and biology. Their promises are in these fields as well as in the bottom-up approach of nanotechnology, and they will be key materials and building block in the 21st century. Whereas the extraction of gold started in the 5th millennium B.C. near Varna (Bulgaria) and reached 10 tons per year in Egypt around 1200-1300 B.C. when the marvelous statue of Touthankamon was constructed, it is probable that “soluble” gold appeared around the 5th or 4th century B.C. in Egypt and China. In antiquity, materials were used in an ecological sense for both aesthetic and curative purposes. Colloidal gold was used to make ruby glass 293 Chem. Rev. 2004, 104, 293−346

Science and technology for water purification in the coming decades

Abstract: One of the most pervasive problems afflicting people throughout the world is inadequate access to clean water and sanitation. Problems with water are expected to grow worse in the coming decades, with water scarcity occurring globally, even in regions currently considered water-rich. Addressing these problems calls out for a tremendous amount of research to be conducted to identify robust new methods of purifying water at lower cost and with less energy, while at the same time minimizing the use of chemicals and impact on the environment. Here we highlight some of the science and technology being developed to improve the disinfection and decontamination of water, as well as efforts to increase water supplies through the safe re-use of wastewater and efficient desalination of sea and brackish water.