Here, we document a collection of ∼7434 MiMIC (Minos Mediated Integration Cassette) insertions of which 2854 are inserted in coding introns. They allowed us to create a library of 400 GFP-tagged ...genes. We show that 72% of internally tagged proteins are functional, and that more than 90% can be imaged in unfixed tissues. Moreover, the tagged mRNAs can be knocked down by RNAi against GFP (iGFPi), and the tagged proteins can be efficiently knocked down by deGradFP technology. The phenotypes associated with RNA and protein knockdown typically correspond to severe loss of function or null mutant phenotypes. Finally, we demonstrate reversible, spatial, and temporal knockdown of tagged proteins in larvae and adult flies. This new strategy and collection of strains allows unprecedented in vivo manipulations in flies for many genes. These strategies will likely extend to vertebrates.
Recent developments in production methods for polymeric materials have meant that thermoplastics for high temperature mechanical performance can now be selectively laser sintered. This paper ...describes the performance and the potential applications of EOS PEEK HP3: a high temperature, laser sintered thermoplastic material.
Thermal, tensile, flexural, compressive and fractural tests were conducted to assess the mechanical response of the material. Physical properties, such as porosity and roughness are also presented along with a discussion on the failure mechanisms of the material during testing.
Finally, the significance of this material in the production of prototype parts, the mechanical requirements of the polymer and limitations of its applications are outlined.
Display omitted
•The mechanical properties of sintered PEEK are similar to injection moulded PEEK.•The mechanical properties of sintered PEEK show an improvement over sintered PA12.•Failures of laser sintered PEEK are predominantly brittle in nature.•Partial sintering between manufactured layers limit structural strength of the material.•Small scale porosity apparent in sub surface layers of sintered PEEK.
The wear and friction in the pitch region of the centre of polymer gear teeth are not well understood. The transition around this point of the tooth between rolling and sliding has an important ...effect on the durability of polymer gear drives and can be simulated using a twin-disc configuration. This paper investigates the rolling–sliding wear behaviour of two poly-ether-ether-ketone (PEEK) discs running against each other with a simplified method of analysing and understanding the dynamic response of high performance polymeric gear teeth.
Tests were conducted without external lubrication over a range of loads and slip ratios, using a twin-disc test rig. The wear and friction mechanisms were closely related to surface morphology, with changes in crystallinity correlating with the severity of operating conditions. Observed failure mechanisms were also related to the structure of the contact surfaces, and included surface melting and contact fatigue.
Overall the PEEK discs were capable of running at low slip ratios for both low and high loads. Their performance reduced with an increase of the slip ratio. The results presented can be used in conjunction with the design process to allow the PEEK to be engineered for a specific high performance gear contact conditions.
The wear of poly-ether-ether-ketone in unlubricated rolling–sliding contact – simulation of high performance polymer gear applications Display omitted
•Tribology of PEEK in dry, roll–slide conditions studied against load and slip-ratio.•Twin discs simulate extremes of polymer gear contact which are not well understood.•Wear, friction and temperature of PEEK discs increased with slip ratio and load.•Wear rates for PEEK were significantly lower than for other similarly tested polymers.•Results can be used to design more effective, highly loaded, and polymeric gear systems.
Polymer gears can be run without lubrication, however, high running temperatures, driven by high contact friction, mean that the operating life of these gears, especially in medium to high power ...transmission applications, tends to be low and limited by wear. This paper describes an attempt to control friction and wear by reducing the running temperatures by using a series of solid lubricant coatings deposited on flanks of the polymer gear teeth. Four potential coatings were selected, viz. molybdenum disulphide (MoS2), graphite flake, boron nitride (hexagonal) and poly-tetra-fluoro-ethylene (PTFE). Each coating was used with both reinforced and unreinforced poly-ether-ether-ketone (PEEK) and unreinforced polyamide (PA). Tests were carried out on coated-coated, coated-steel and coated gears running against uncoated gears. Wear rates (in the form of weight loss) and running temperatures were recorded. Results indicate that PTFE provided the greatest reduction in frictional forces and that failure mechanisms were predominately in delamination of the coatings and abrasive wear.
► DFL coatings applied to surface of polymer gears to control tribological properties. ► Effectiveness of DFLs varied with base material and gear mesh combination. ► PTFE is the most effective coating for reducing temperature and wear in unreinforced polymer gears. ► Failure of the DFL coatings were predominately in delamination and abrasive wear. ► DFL coatings shown not to be effective in polymer composite gears.
Mutations in the genes encoding isocitrate dehydrogenase, IDH1 and IDH2, have been reported in gliomas, myeloid leukemias, chondrosarcomas and thyroid cancer. We discovered IDH1 and IDH2 mutations in ...34 of 326 (10%) intrahepatic cholangiocarcinomas. Tumor with mutations in IDH1 or IDH2 had lower 5-hydroxymethylcytosine and higher 5-methylcytosine levels, as well as increased dimethylation of histone H3 lysine 79 (H3K79). Mutations in IDH1 or IDH2 were associated with longer overall survival (P=0.028) and were independently associated with a longer time to tumor recurrence after intrahepatic cholangiocarcinoma resection in multivariate analysis (P=0.021). IDH1 and IDH2 mutations were significantly associated with increased levels of p53 in intrahepatic cholangiocarcinomas, but no mutations in the p53 gene were found, suggesting that mutations in IDH1 and IDH2 may cause a stress that leads to p53 activation. We identified 2309 genes that were significantly hypermethylated in 19 cholangiocarcinomas with mutations in IDH1 or IDH2, compared with cholangiocarcinomas without these mutations. Hypermethylated CpG sites were significantly enriched in CpG shores and upstream of transcription start sites, suggesting a global regulation of transcriptional potential. Half of the hypermethylated genes overlapped with DNA hypermethylation in IDH1-mutant gliobastomas, suggesting the existence of a common set of genes whose expression may be affected by mutations in IDH1 or IDH2 in different types of tumors.
We describe a transgenesis platform for Drosophila melanogaster that integrates three recently developed technologies: a conditionally amplifiable bacterial artificial chromosome (BAC), ...recombineering, and bacteriophage ΦC31-mediated transgenesis. The BAC is maintained at low copy number, facilitating plasmid maintenance and recombineering, but is induced to high copy number for plasmid isolation. Recombineering allows gap repair and mutagenesis in bacteria. Gap repair efficiently retrieves DNA fragments up to 133 kilobases long from P1 or BAC clones. ΦC31-mediated transgenesis integrates these large DNA fragments at specific sites in the genome, allowing the rescue of lethal mutations in the corresponding genes. This transgenesis platform should greatly facilitate structure/function analyses of most Drosophila genes.
We demonstrate the versatility of a collection of insertions of the transposon Minos-mediated integration cassette (MiMIC), in Drosophila melanogaster. MiMIC contains a gene-trap cassette and the ...yellow+ marker flanked by two inverted bacteriophage ΦC31 integrase attP sites. MiMIC integrates almost at random in the genome to create sites for DNAmanipulation. The attP sites allow the replacement of the intervening sequence of the transposon with any other sequence through recombinase-mediated cassette exchange (RMCE). We can revert insertions that function as gene traps and cause mutant phenotypes to revert to wild type by RMCE and modify insertions to control GAL4 or QF overexpression systems or perform lineage analysis using the Flp recombinase system. Insertions in coding introns can be exchanged with protein-tag cassettes to create fusion proteins to follow protein expression and perform biochemical experiments. The applications of MiMIC vastly extend the D. melanogaster toolkit.
The first complete measurement of the β-decay strength distribution of _{17}^{45}Cl_{28} was performed at the Facility for Rare Isotope Beams (FRIB) with the FRIB Decay Station Initiator during the ...second FRIB experiment. The measurement involved the detection of neutrons and γ rays in two focal planes of the FRIB Decay Station Initiator in a single experiment for the first time. This enabled an analytical consistency in extracting the β-decay strength distribution over the large range of excitation energies, including neutron unbound states. We observe a rapid increase in the β-decay strength distribution above the neutron separation energy in _{18}^{45}Ar_{27}. This was interpreted to be caused by the transitioning of neutrons into protons excited across the Z=20 shell gap. The SDPF-MU interaction with reduced shell gap best reproduced the data. The measurement demonstrates a new approach that is sensitive to the proton shell gap in neutron rich nuclei according to SDPF-MU calculations.
Full text
Available for:
CMK, CTK, FMFMET, NUK, UL
Per- and polyfluoroalkyl substances (PFAS) are present in water and >99% of human serum. They are found in brains of wildlife; however, little is known about effects on the developing brain. To ...determine the effects of PFAS on brain and cardiac innervation, we conducted an outdoor mesocosm experiment with Northern leopard frog larvae (Rana pipiens) exposed to control, 10 ppb perfluorooctane sulfonate (PFOS), or a PFAS mixture totaling 10 ppb that mimicked aqueous film forming foam-impacted surface water (4 ppb PFOS, 3 ppb perfluorohexane sulfonate, 1.25 ppb perfluorooctanoate, 1.25 ppb perfluorohexanoate, and 0.5 ppb perfluoro-n-pentanoate). Water was spiked with PFAS and 25 larvae (Gosner stage (GS) 25) added to each mesocosm (n = 4 mesocosms per treatment). After 30 days, we harvested eight brains per mesocosm and remaining larvae developed to GS 46 (i.e. metamorphosis) before brains and hearts were collected. Weight, length, GS, and time to metamorphosis were recorded. Brain concentrations of all five PFAS were quantified using LC/MS/MS. Dopamine and metabolites, serotonin and its metabolite, norepinephrine, γ-aminobutyric acid, and glutamate were quantified using High Performance Liquid Chromatography with electrochemical detection while acetylcholine and acetylcholinesterase activity were quantified with the Invitrogen Amplex Red Acetylcholine Assay. PFOS accumulated in the brain time- and dose-dependently. After 30 days, the mixture decreased serotonin while both PFAS treatments decreased glutamate. Interestingly, acetylcholine increased in PFAS treatments at GS 46. This research shows that developmental environmentally relevant exposure to PFAS changes neurotransmitters, especially acetylcholine.
•PFAS neurotoxicity was tested in developing Northern leopard frogs.•PFOS, or a PFAS mixture produced time- and dose-dependent brain accumulation.•Developmental PFAS exposure changes neurotransmitters, especially acetylcholine.•PFAS exposure needs to be further evaluated for long-term neurological effects.
PDF
![P[acman]: A BAC Transgenic ...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0036-8075_1095-9203/small "P[acman]: A BAC Transgenic Platform for Targeted Insertion of Large DNA Fragments in D. melanogaster")
