149 research outputs found
Directional growth of polypyrrole and polythiophene wires
This work establishes an innovative electrochemical approach to the template-free growth of conducting polypyrrole and polythiophene wires along predictable interelectrode paths up to 30 um in length. These wires have knobby structures with diameters as small as 98 nm. The conductivity of the polypyrrole wires is 0.5+/=0.3 S cm-1; that of the polythiophene wires is 7.6+/=0.8 S cm-1. Controlling the growth path enables fabrication of electrode-wire-target assemblies where the target is a biological cell in the interelectrode gap. Such assemblies are of potential use in cell stimulation studies.Peer reviewedPhysicsMicrobiology and Molecular Genetic
Blueberry Progress Reports
The 1982 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Life Sciences and Agriculture Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Introduction
2. Blueberry IPM Program
3. Guthion Drift Study
4. Control, Biology, and Ecology of Insects
5. Blueberry Diseases: Incidence and Control
6. Physiology and Culture of the Lowbush Blueberry
7. Weed Control in Lowbush Blueberries
8. Pruning Blueberrie
Nuclear Transparency to Intermediate-Energy Protons
Nuclear transparency in the (e,e'p) reaction for 135 < Tp < 800 MeV is
investigated using the distorted wave approximation. Calculations using
density-dependent effective interactions are compared with phenomenological
optical potentials. Nuclear transparency is well correlated with proton
absorption and neutron total cross sections. For Tp < 300 MeV there is
considerable sensitivity to the choice of optical model, with the empirical
effective interaction providing the best agreement with transparency data. For
Tp > 300 MeV there is much less difference between optical models, but the
calculations substantially underpredict transparency data and the discrepancy
increases with A. The differences between Glauber and optical model
calculations are related to their respective definitions of the semi-inclusive
cross section. By using a more inclusive summation over final states the
Glauber model emphasizes nucleon-nucleon inelasticity, whereas with a more
restrictive summation the optical model emphasizes nucleon-nucleus
inelasticity; experimental definitions of the semi-inclusive cross section lie
between these extremes.Comment: uuencoded gz-compressed tar file containing revtex and bbl files and
5 postscript figures, totalling 31 pages. Uses psfi
Blueberry Progress Reports
The 1983 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Introduction
2. Forest Tent Caterpillar in Blueberries
3. Control, Biology, and Ecology of Insects Affecting Lowbush Blueberries
4. Blueberry Diseases: Incidence and Control
5. Physiology and Culture of the Lowbush Blueberry
6. Weed Control in Lowbush Blueberry Fields
7. Product Development of Lowbush Blueberrie
Unauthorized Horizontal Spread in the Laboratory Environment: The Tactics of Lula, a Temperate Lambdoid Bacteriophage of Escherichia coli
We investigated the characteristics of a lambdoid prophage, nicknamed Lula, contaminating E. coli strains from several sources, that allowed it to spread horizontally in the laboratory environment. We found that new Lula infections are inconspicuous; at the same time, Lula lysogens carry unusually high titers of the phage in their cultures, making them extremely infectious. In addition, Lula prophage interferes with P1 phage development and induces its own lytic development in response to P1 infection, turning P1 transduction into an efficient vehicle of Lula spread. Thus, using Lula prophage as a model, we reveal the following principles of survival and reproduction in the laboratory environment: 1) stealth (via laboratory material commensality), 2) stability (via resistance to specific protocols), 3) infectivity (via covert yet aggressive productivity and laboratory protocol hitchhiking). Lula, which turned out to be identical to bacteriophage phi80, also provides an insight into a surprising persistence of T1-like contamination in BAC libraries
Perioperative characteristics, histologic diagnosis, complications, and outcomes of dogs undergoing percutaneous drainage, sclerotherapy or surgical management of intrarenal cystic lesions: 18 dogs (2004-2021)
BACKGROUND: Canine intrarenal cystic lesions (ICLs) are infrequently reported in the veterinary literature. Several treatment options have been described including cyst fenestration (partial nephrectomy/deroofing) +/- omentalization, sclerotherapy using alcohol as a sclerosing agent, percutaneous cyst drainage (PCD), and ureteronephrectomy. Information regarding presenting clinical signs, physical examination findings, histologic diagnosis and outcomes of dogs with ICLs treated by different methods is limited. Medical records of 11 institutions were retrospectively reviewed to identify dogs that underwent PCD, sclerotherapy, surgical deroofing +/- omentalization, or ureteronephrectomy for management of ICLs from 2004 to 2021. Six weeks postoperative/post-procedural follow-up was required. Cases suspected to represent malignancy on preoperative imaging were excluded. The study objective was to provide information regarding perioperative characteristics, complications, and outcomes of dogs undergoing treatment of ICLs. RESULTS: Eighteen dogs were included, with 24 ICLs treated. Ten had bilateral. There were 15 males and 3 females, with crossbreeds predominating. PCD, sclerotherapy, deroofing and ureteronephrectomy were performed in 5 (5 ICLs treated), 7 (11 ICLs), 6 (6), and 7 (7) dogs, respectively, with 5 dogs undergoing > 1 treatment. Seven dogs experienced 8 complications, with requirement for additional intervention commonest. PCD, sclerotherapy and deroofing resulted in ICL resolution in 0/5, 3/11 and 3/6 treated ICLs, respectively. Histopathology identified renal cysts (RCs) in 7/13 dogs with histopathology available and neoplasia in 6/13 (4 malignant, 2 benign). Of 5 dogs diagnosed histopathologically with neoplasia, cytology of cystic fluid failed to identify neoplastic cells. Among 7 dogs with histologically confirmed RCs, 4 had concurrent ICLs in ipsilateral/contralateral kidney, compared with 2/6 dogs with histologically confirmed neoplasia. CONCLUSIONS: Benign and neoplastic ICLs were approximately equally common and cystic fluid cytology failed to differentiate the 2. Among renal-sparing treatments, deroofing most commonly resulted in ICL resolution. Presence of concurrent ICLs in ipsilateral/contralateral kidney does not appear reliable in differentiating benign from malignant ICLs
Microstructure Fabrication
Contains reports on seven research projects.National Science Foundation (Grant ENG78-10436)M.I.T. Sloan Fund for Basic ResearchJoint Services Electronics Program (Contract DAAG29-78-C-0020)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)M.I.T. Cabot FundLawrence Livermore Laboratory (Subcontract 206-92-09)National Science Foundation (Grant DMR78-23555
Trapping \u3ci\u3ePhyllophaga \u3c/i\u3espp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.
The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester
Channel Coupling in Reactions
The sensitivity of momentum distributions, recoil polarization observables,
and response functions for nucleon knockout by polarized electrons to channel
coupling in final-state interactions is investigated using a model in which
both the distorting and the coupling potentials are constructed by folding
density-dependent effective interactions with nuclear transition densities.
Calculations for O are presented for 200 and 433 MeV ejectile energies,
corresponding to proposed experiments at MAMI and TJNAF, and for C at 70
and 270 MeV, corresponding to experiments at NIKHEF and MIT-Bates. The relative
importance of charge exchange decreases as the ejectile energy increases, but
remains significant for 200 MeV. Both proton and neutron knockout cross
sections for large recoil momenta, MeV/c, are substantially
affected by inelastic couplings even at 433 MeV. Significant effects on the
cross section for neutron knockout are also predicted at smaller recoil
momenta, especially for low energies. Polarization transfer for proton knockout
is insensitive to channel coupling, even for fairly low ejectile energies, but
polarization transfer for neutron knockout retains nonnegligible sensitivity to
channel coupling for energies up to about 200 MeV. The present results suggest
that possible medium modifications of neutron and proton electromagnetic form
factors for can be studied using recoil
polarization with relatively little sensitivity due to final state
interactions.Comment: Substantially revised version accepted by Phys. Rev. C; shortened to
49 pages including 21 figure
Evidence That Two ATP-Dependent (Lon) Proteases in Borrelia burgdorferi Serve Different Functions
The canonical ATP-dependent protease Lon participates in an assortment of biological processes in bacteria, including the catalysis of damaged or senescent proteins and short-lived regulatory proteins. Borrelia spirochetes are unusual in that they code for two putative ATP-dependent Lon homologs, Lon-1 and Lon-2. Borrelia burgdorferi, the etiologic agent of Lyme disease, is transmitted through the blood feeding of Ixodes ticks. Previous work in our laboratory reported that B. burgdorferi lon-1 is upregulated transcriptionally by exposure to blood in vitro, while lon-2 is not. Because blood induction of Lon-1 may be of importance in the regulation of virulence factors critical for spirochete transmission, the clarification of functional roles for these two proteases in B. burgdorferi was the object of this study. On the chromosome, lon-2 is immediately downstream of ATP-dependent proteases clpP and clpX, an arrangement identical to that of lon of Escherichia coli. Phylogenetic analysis revealed that Lon-1 and Lon-2 cluster separately due to differences in the NH2-terminal substrate binding domains that may reflect differences in substrate specificity. Recombinant Lon-1 manifested properties of an ATP-dependent chaperone-protease in vitro but did not complement an E. coli Lon mutant, while Lon-2 corrected two characteristic Lon-mutant phenotypes. We conclude that B. burgdorferi Lons -1 and -2 have distinct functional roles. Lon-2 functions in a manner consistent with canonical Lon, engaged in cellular homeostasis. Lon-1, by virtue of its blood induction, and as a unique feature of the Borreliae, may be important in host adaptation from the arthropod to a warm-blooded host
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