1,818 research outputs found
Annabella australiensis gen. & sp. nov. (Helotiales, Cordieritidaceae) from South Australian mangroves
A new genus of helotialean fungi, Annabella gen. nov. (Cordieritidaceae), is described to accommodate Annabella australiensis sp. nov. This species was collected on attached decaying wood of Avicennia marina, a common mangrove species found in protected waters of southern Australia. Annabella is distinctive among Cordieritidaceae in having relatively small perithecioid hyaline to yellowish apothecia and by the absence of an ionomidotic reaction. The apothecial shape and size of Annabella is most similar to Skyttea. The molecular phylogenetic analysis of a concatenated dataset of three ribosomal nuclear loci confirms the placement of Annabella within Cordieritidaceae, as a sister clade to Skyttea
An economical strategy for chromosome walking in the Neurospora crassa pMOcosX library
Chromosome walking using ordered genomic libraries is demanding of both labor and materials. Such libraries are often stored as a set of 96 well microtiter plates with each well containing an individual clone. The library is typically prepared for screening by replicating plates onto ~11 x 7 cm membranes placed on a suitable growth medium. Colonies are lysed in situ and the cellular material washed off leaving DNA bound to the membranes (colony blots). To extend the walk, the library is screened by probing the set of colony blots for homology to sequences close to the terminus identified in the preceding step. Once clones are identified, they are mapped for one or more restriction enzymes, aligned, and a sequence extending the walk in the desired direction is selected to initiate the next phase. The Neurospora crassa genomic library pMOcosX (Orbach 1994 Gene 150:159-162) comprises 50, 96 well microtiter plates. A conventional screening program uses 50 membranes and, due to the practicalities of hybridizing 50 membranes simultaneously, sometimes several rounds of hybridization. In this note we describe a chromosome walking strategy in the pMOcosX library that minimizes the scale of screening and also obviates the need for restriction mapping prior to commencing the next step, which in our experience is a rate limiting factor. We have used this method to establish contigs of 110 and 240 kb on LG
Quick method for producing template for PCR from Neurospora cultures
We have used the following method routinely for the past year and found it reliable even in undergraduate classes
Polymorphism in the 3 flank of his-3 and the origin of Neurospora wild-types
The legitimacy of classic wild-type strains deposited in the FGSC has been assessed by examining polymorphisms (Newmeyer et al. 1987 Neurospora Newsl. 34:46-51; Catcheside, D.G. 1975 Aust J Biol Sci 28:213-225). These studies show that Lindegren a (FGSC 541), Lindegren 1A (FGSC 354), Abbott 12a (FGSC 1758) and St Lawrence 79a (FGSC 533) are probably not authentic. We have examined the cog-region (distal of histidine-3 on Linkage Group I) in a number of strains and found four different RFLP variants, a different one in each of the alleged progenitor stocks of the modern laboratory strains (Yeadon and Catcheside, 1995. Curr. Genet., in press). The pedigree diagram (based on Catcheside 1975 and Newmeyer et al. 1987) shows the cog-region variant present in each of the strains we examined. Our nomenclature for cogalleles reflects the first strain in which it was found, for example cogEa in Ema. FGSC stock numbers are shown below the strain name. T391, our laboratory stock number, contains his-3 K26, a mutant generated (Angel et al. 1970. Aust J Biol Sci 23:1229-1240) in Lindegren Y8743 (Barratt and Garnjobst, 1949. Genetics 34:351-369)
Experimental Spinal Fusion With Recombinant Human Bone Morphogenetic Protein-2 Without Decortication of Osseous Elements
Study Design. L4-L5 intertransverse process fusions were produced with 58 μg, 230 μg, or 920 μg of recombinant human bone morphogenetic protein-2 in 20 dogs. Eleven had traditional decortication of posterior elements before insertion of the implant. Nine were left undecorticated. All animals were evaluated 3 months after surgery.
Objectives. To determine whether decortication is a prerequisite for successful fusion in the presence of osteoinductive proteins such as bone morphogenetic protein-2.
Summary of Background Data. Recombinant osteoinductive proteins can induce de novo bone in ectopic soft-tissue sites in the absence of bone marrow elements. Traditional methods for achieving spinal fusion rely on exposure of bone marrow through decortication to facilitate osteogenesis. It is hypothesized that the presence of an implanted osteoinductive protein obviates the need for exposure and release of host inductive factors.
Methods. Recombinant human bone morphogenetic protein-2-induced intertransverse process fusions were performed with and without decortication. Fusion sites were evaluated by computed tomography imaging, high-resolution radiography, manual testing, mechanical testing, and histologic analysis.
Results. One hundred percent of decorticated spines and 89% of undecorticated spines were clinically fused by 3 months. Ninety-one percent of decorticated spines and 78% of undecorticated specimens exhibited bilateral transverse process osseous bridging. The only spines that failed to achieve solid bilateral arthrodesis were in the lowest dose group. With the higher two doses, there was histologic evidence of osseous continuity between the fusion mass and undecorticated transverse processes.
Conclusions. There were no statistical differences in clinical and radiographic fusion rates between decorticated and undecorticated sites. With higher doses of recombinant human bone morphogenetic protein-2, there was little histologic distinction between fusions in decorticated versus undecorticated spines
Effective Doses of Recombinant Human Bone Morphogenetic Protein-2 in Experimental Spinal Fusion
Study Design Nineteen dogs underwent L4-L5 intertransverse process fusions with either 58 μg, 115 μg, 230 μg, 460 μg, or 920 μg of recombinant human bone morphogenetic protein-2 carried by a polylactic acid polymer. A previous study (12 dogs) compared 2300 μg of recombinant human bone morphogenetic protein-2, autogenous iliac bone, and carrier alone in this model. All fusions subsequently were compared.
Objectives To characterize the dose-response relationship of recombinant human bone morphogenetic protein-2 in a spinal fusion model.
Summary of Background Data Recombinant osteoinductive morphogens, such as recombinant human bone morphogenetic protein-2, are effective in vertebrate diaphyseal defect and spinal fusion models. It is hypothesized that the quality of spinal fusion produced with recombinant human bone morphogenetic protein-2, above a threshold dose, does not change with increasing amounts of inductive protein.
Methods After decortication of the posterior elements, the designated implants were placed along the intertransverse process space bilaterally. The fusion sites were evaluated after 3 months by computed tomography imaging, high-resolution radiography, manual testing, mechanical testing, and histologic analysis.
Results As in the study using 2300 μg of recombinant human bone morphogenetic protein-2, implantation of 58–920 μg of recombinant human bone morphogenetic protein-2 successfully resulted in intertransverse process fusion in the dog by 3 months. This had not occurred in animals containing autograft or carrier alone. The cross-sectional area of the fusion mass and mechanical stiffness of the L4-L5 intersegment were not dose-dependent. Histologic findings varied but were not related to rhBMP-2 dose. Inflammatory reaction to the composite implant was proportional inversely to the volume of the fusion mass.
Conclusions No mechanical, radiographic, or histologic differences in the quality of intertransverse process fusion resulted from a 40-fold variation in dose of recombinant human bone morphogenetic protein-2
An educational video of the basic procedures in gonioscopy
An educational video of the basic procedures in gonioscop
Analysis of reactions during sintering of CuO-doped 3Y-TZP nano-powder composites
3Y-TZP (yttria-doped tetragonal zirconia) and CuO nano powders were prepared by co-precipitation and copper oxalate complexation–precipitation techniques, respectively. During sintering of powder compacts (8 mol% CuO-doped 3Y-TZP) of this two-phase system several solid-state reactions clearly influence densification behaviour. These reactions were analysed by several techniques like XPS, DSC/TGA and high-temperature XRD. A strong dissolution of CuO in the 3Y-TZP matrix occurs below 600 °C, resulting in significant enrichment of CuO in a 3Y-TZP grain-boundary layer with a thickness of several nanometres. This “transient” liquid phase strongly enhances densification. Around 860 °C a solid-state reaction between CuO and yttria as segregated to the 3Y-TZP grain boundaries occurs, forming Y2Cu2O5. This solid-state reaction induces the formation of the thermodynamic stable monoclinic zirconia phase. The formation of this solid phase also retards densification. Using this knowledge of microstructural development during sintering it was possible to obtain a dense nano–nano composite with a grain size of only 120 nm after sintering at 960 °C
Fabrication of arrays of gold islands on self-assembled monolayers using pulsed laser deposition through nanosieves
Sandwich structures of gold-self-assembled monolayer-gold were prepared by deposition of gold on alkylthiolate self-assembled monolayers on polycrystalline gold, using pulsed laser deposition (PLD) through a nanosieve. The arrays of sandwiches, around 600 nm in diameter, approximately 10 nm high, and spaced 1.6 ím apart, were analyzed using tapping mode atomic force microscopy. Electrochemical copper deposition experiments showed that of the islands deposited on octadecanethiolate monolayers about 15% were electrically insulated from the bottom gold electrode. This means that PLD is a suitable technique for the fabrication of metal-SAM-metal sandwich structures
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