240 research outputs found
A Fusarium Following Frost-Injury of Robinia
In the fall of 1935 a number of specimens of seedlings of Robinia pseudo-acacia L. were submitted to the Department of Botany of Iowa State College for the investigation of a canker which was girdling the sterns of these plants at or about the ground line. On a majority of the specimens examined, the injury consisted of a sunken area approximately two centimeters in length completely surrounding the stem. The wood under these cankers was materially browned and the cambium was dead. Many of these cankers were covered with orange sporodochia of a fungus which microscopic examination proved to be a member of the genus Fusarium. A survey of the extent of the disease was made and the identity of the fungus and its relationship as a possible factor in the causation of the canker was investigated
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Frame Semantics in Text-to-Scene Generation
3D graphics scenes are difficult to create, requiring users to learn and utilize a series of complex menus, dialog boxes, and often tedious direct manipulation techniques. By giving up some amount of control afforded by such interfaces we have found that users can use natural language to quickly and easily create a wide variety of 3D scenes. Natural language offers an interface that is intuitive and immediately accessible by anyone, without requiring any special skill or training. The WordsEye system (http://www.wordseye.com) has been used by several thousand users on the web to create over 10,000 scenes. The system relies on a large database of 3D models and poses to depict entities and actions. We describe how the current version of the system incorporates the type of lexical and real-world knowledge needed to depict scenes from language
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Collecting Spatial Information for Locations in a Text-to-Scene Conversion System
We investigate using Amazon Mechanical Turk (AMT) for building a low-level description corpus and populating VigNet, a comprehensive semantic resource that we will use in a text-to-scene generation system. To depict a picture of a location, VigNet should contain the knowledge about the typical objects in that location and the arrangements of those objects. Such information is mostly common-sense knowledge that is taken for granted by human beings and is not stated in existing lexical resources and in text corpora. In this paper we focus on collecting objects of locations using AMT. Our results show that it is a promising approach
Chalcogenide glasses for photonics device applications
Chalcogenides are compounds formed predominately from one or more of the chalcogen elements; sulphur, selenium and tellurium. Although first studied over fifty years ago, interest in chalcogenide glasses has, over the past few years, increased significantly as glasses, crystals and alloys find new life in a wide range of photonic devices. This chapter begins with an overview of chalcogenide glass compositions, their purification, synthesis and fabrication. Focussing on more novel gallium lanthanum sulphide based chalcogenides, as well as reviewing more established materials such as arsenic trisulphide based glasses we then explore the purification and synthesis of these materials, along with their basic optical and thermal properties. Next the fabrication of these versatile glasses into a variety of forms; including thin films, microspheres and optical fibers is explained. This chapter ends with an overview of representative applications of these exciting optoelectronic materials
A Brief History, Status, and Perspective of Modified Oligonucleotides for Chemotherapeutic Applications
The advent of rapid and efficient methods of oligonucleotide synthesis has allowed the design of modified oligonucleotides that are complementary to specific nucleotide sequences in mRNA targets. Such modified oligonucleotides can be used to disrupt the flow of genetic information from transcribed mRNAs to proteins. This antisense strategy has been used to develop therapeutic oligonucleotides against cancer and various infectious diseases in humans. This overview reports recent advances in the application of oligonucleotides as drug candidates, describes the relationship between oligonucleotide modifications and their therapeutic profiles, and provides general guidelines for enhancing oligonucleotide drug properties.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143788/1/cpnc0401.pd
Sequential NMR assignments of labile protons in DNA using two-dimensional nuclear-Overhauser-enhancement spectroscopy with three jump-and-return pulse sequences
Two-dimensional nuclear Overhauser enhancement (NOESY) spectra of labile protons were recorded in H2O solutions of a protein and of a DNA duplex, using a modification of the standard NOESY experiment with all three 90 degree pulses replaced by jump-and-return sequences. For the protein as well as the DNA fragment the strategically important spectral regions could be recorded with good sensitivity and free of artifacts. Using this procedure, sequence-specific assignments were obtained for the imino protons, C2H of adenine, and C4NH2 of cytosine in a 23-base-pair DNA duplex which includes the 17-base-pair OR3 repressor binding site of bacteriophage lambda. Based on comparison with previously published results on the isolated OR3 binding site, these data were used for a study of chain termination effects on the chemical shifts of imino proton resonances of DNA duplexes
Enzymatic Activities and DNA Substrate Specificity of Mycobacterium tuberculosis DNA Helicase XPB
XPB, also known as ERCC3 and RAD25, is a 3′→5′ DNA repair helicase belonging to the superfamily 2 of helicases. XPB is an essential core subunit of the eukaryotic basal transcription factor complex TFIIH. It has two well-established functions: in the context of damaged DNA, XPB facilitates nucleotide excision repair by unwinding double stranded DNA (dsDNA) surrounding a DNA lesion; while in the context of actively transcribing genes, XPB facilitates initiation of RNA polymerase II transcription at gene promoters. Human and other eukaryotic XPB homologs are relatively well characterized compared to conserved homologs found in mycobacteria and archaea. However, more insight into the function of bacterial helicases is central to understanding the mechanism of DNA metabolism and pathogenesis in general. Here, we characterized Mycobacterium tuberculosis XPB (Mtb XPB), a 3′→5′ DNA helicase with DNA-dependent ATPase activity. Mtb XPB efficiently catalyzed DNA unwinding in the presence of significant excess of enzyme. The unwinding activity was fueled by ATP or dATP in the presence of Mg2+/Mn2+. Consistent with the 3′→5′ polarity of this bacterial XPB helicase, the enzyme required a DNA substrate with a 3′ overhang of 15 nucleotides or more. Although Mtb XPB efficiently unwound DNA model substrates with a 3′ DNA tail, it was not active on substrates containing a 3′ RNA tail. We also found that Mtb XPB efficiently catalyzed ATP-independent annealing of complementary DNA strands. These observations significantly enhance our understanding of the biological roles of Mtb XPB
Cutaneous lesions of the external ear
Skin diseases on the external aspect of the ear are seen in a variety of medical disciplines. Dermatologists, othorhinolaryngologists, general practitioners, general and plastic surgeons are regularly consulted regarding cutaneous lesions on the ear
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