Estimating the polygenicity (proportion of causally associated single nucleotide polymorphisms (SNPs)) and discoverability (effect size variance) of causal SNPs for human traits is currently of ...considerable interest. SNP-heritability is proportional to the product of these quantities. We present a basic model, using detailed linkage disequilibrium structure from a reference panel of 11 million SNPs, to estimate these quantities from genome-wide association studies (GWAS) summary statistics. We apply the model to diverse phenotypes and validate the implementation with simulations. We find model polygenicities (as a fraction of the reference panel) ranging from ≃ 2 × 10-5 to ≃ 4 × 10-3, with discoverabilities similarly ranging over two orders of magnitude. A power analysis allows us to estimate the proportions of phenotypic variance explained additively by causal SNPs reaching genome-wide significance at current sample sizes, and map out sample sizes required to explain larger portions of additive SNP heritability. The model also allows for estimating residual inflation (or deflation from over-correcting of z-scores), and assessing compatibility of replication and discovery GWAS summary statistics.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Water-atomized and gas-atomized 17-4 PH stainless steel powder were used as feedstock in selective laser melting process. Gas atomized powder revealed single martensitic phase after printing and heat ...treatment independent of energy density. As-printed water atomized powder contained dual martensitic and austenitic phase regardless of energy density. The H900 heat treatment cycle was not effective in enhancing mechanical properties of the water-atomized powder after laser melting. However, after solutionizing at 1315ºC and aging at 482 °C fully martensitic structure was observed with hardness (40.2 HRC), yield strength (1000 MPa) and ultimate tensile strength (1261 MPa) comparable to those of gas atomized (42.7 HRC, 1254 MPa and 1300 MPa) and wrought alloy (39 HRC, 1170 MPa and 1310 MPa), respectively. Improved mechanical properties in water-atomized powder was found to be related to presence of finer martensite and higher volume fraction of fine Cu-enriched precipitates. Our results imply that water-atomized powder is a promising cheaper feedstock alternative to gas-atomized powder.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Selective Laser Melting (SLM) is a promising technique for the fabrication of complex net shaped parts of many metals. However, the high melting temperature of tungsten makes fabricating complex ...parts via SLM difficult. A study was undertaken to understand the effect of process parameters like hatch spacing and scan speed on the densification of tungsten by the SLM technique. Experiments were conducted at hatch spacing of 15 and 30μm and scan speeds in the range 200–1400mm/s. A constant laser power of 90W and a powder layer thickness of 30μm were used. Rectangular cuboids of 7.8±1.4mm×10.1±0.1mm×10.1±0.04mm were printed using various process parameters and analyzed for densification. The densification of tungsten was found to increase with an increase in energy density. A maximum density of 75% theoretical was achieved at energy density of 1000J/mm3.
•Densification of tungsten by the SLM technique is studied.•Densification of tungsten increased with a decrease in scan speed and hatch spacing.•Scan speed contributed to 75.7% of variation in densification.•Hatch spacing contributed to only 7.1% of variation in densification.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Predicting the influence of material composition on the printability of highly filled metal powder-polymer systems present a significant challenge in metal fused filament fabrication (MF3). The ...current work presents an approach to evaluate new material compositions used to fabricate filaments for their printability. In this study, filaments with 59 vol.% (87 wt.%) of Ti-6Al-4V powder with two particle size distributions {fine (D50 = 13 μm) and coarse (D50 = 30 μm)} dispersed in a polymer matrix were examined. The respective forces to overcome the pressure drop, for successful printing, were found to increase with an increase in the feed rate, and were also dependent on the feedstock viscosity. In addition, shear forces estimated from the filament shear strength were found to be limiting conditions for successful printing. Based on these observations, a criterion has been proposed to evaluate filament printability from the predicted limiting force for filament failure and the required force to achieve continuous material flow for successful printing. Under present experimental conditions, successful printing was achieved up to 2 mm/s and 8 mm/s for fine and coarse powder filaments, in good agreement with the model predictions. The model was experimentally tested and found to be applicable for other compositions. The results demonstrate a new printability criterion to design novel materials for MF3.
•Printability of Ti64 alloy powder-polymer filaments for fused filament fabrication.•Filament viscosity and feed rate influences the pressure drop at the nozzle exit.•Filament strength dictates successful material extrusion and printing.•Powder attributes influences printability and print speed.•Predictive process models allow materials development in fused filament fabrication.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The effects of powder characteristics (powder shape, size and type) and processing conditions (laser power and scanning speed) on the mechanical properties and microstructures of laser powder bed ...fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength, hardness of L-PBF parts are sensitive to energy density and starting powder shape, size and type. The density and mechanical properties of both water and gas-atomized powders increased with increased energy density. The gas-atomized (D50 = 13 μm) powders which are spherical in shape and water-atomized (D50 = 17 μm) powders of high tap density produced low-porosity and high-density (~97% density) L-PBF parts at low energy densities of 64 and 80 J/mm3. The increase in energy density to 104 J/mm3 resulted in high dense (97 ± 0.5%) water- and gas-atomized powders L-PBF parts. However, even at a high % theoretical density (97 ± 1%), the properties of L-PBF parts varied over a relatively large range (UTS: 500–1100 MPa; hardness: 25–39 HRC; elongation: 10–25%). This large variation in mechanical properties could be attributed the martensite and austenite phase as well as grain size in the L-PBF parts. Furthermore, the martensite and austenite phase content and of the L-PBF parts were also sensitive to the energy density and starting powder type.
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•17-4PH particle characteristics strongly influence densification in L-PBF parts.•Irregular shaped powders with high tap density can produce near full density parts.•Mechanical properties and microstructures are sensitive to powder characteristics.•A large variation in mechanical properties was observed for highly dense parts.•Water-atomized parts of UTS 1100 MPa were produced at energy density 104 J/mm3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This paper aims to break the current material-process-property tradeoffs in metal fused filament fabrication (MF3) to effectively fabricate Ti-6Al-4V alloy specimens beyond 90% relative density ...without any post-processing with consistent mechanical properties and microstructure, which are critical for aerospace and medical applications. Existing knowledge gaps in MF3 3D printing fail to address how properties scale from the filament processing stage to green part printing to sintering and what contributing factors cause significant deviation in mechanical properties in samples having the same sintered densities. To tackle these gaps, this work holistically investigates four key aspects specifically for MF3 of Ti-6Al-4V to address a) influence of filament extrusion conditions on filament density variance and diameter control, b) use of the design of experiments to identify factors influencing MF3 3D printed green sample density and dimensions, c) identifying sintering time and temperature conditions that yield densities beyond 90% and mechanical properties close to literature and d) powder attributes (size and interstitial concentrations) and its effect on sintered density and mechanical properties for MF3 samples.
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•influence of filament extrusion conditions on filament density variance and diameter control,•use of the design of experiments to identify factors influencing MF3 3D printed green sample density and dimensions,•identifying sintering time and temperature conditions that yield densities beyond 90% and mechanical properties close to literature and•powder attributes (size and interstitial concentrations) and its effect on sintered density and mechanical properties for MF3 samples
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Antimicrobial resistance (AMR) has emerged as one of the most serious worldwide public health issues of the twenty-first century. The expeditious rise of AMR has urged the development of new, natural ...effective therapeutic strategies against drug-resistant pathogens. Endophytic fungi, which inhabit distinctive environments like endosymbiotic relationships with plants, are gaining interest as alternative reservoirs for novel compounds that exhibit a broad range of chemical diversity and unique modes of action by releasing a variety of secondary metabolites with antimicrobial properties. The objective of the current research was to isolate and identify endophytic fungal species from leaves of Tradescantia pallida and to investigate their antagonistic effects on Multi-Drug-Resistant human pathogens. Endophytic fungus TPL11 and TPL14 showed maximum inhibition in agar plug and agar well diffusion assay. The ethyl acetate crude extract effectively suppressed growth of MRSA (Methicillin-resistant Staphylococcus aureus) ATCC 43300,700699 strains and VRE (Vancomycin-resistant Enterococcus) with the Inhibition zone of 22 ± 0.05, 23 ± 0.11 and 24 ± 0.11 mm respectively with minimum inhibitory concentration (MIC) of 3.125 µg/mL. Whereas TPL11 fungus revealed antibiosis of 22 ± 0.05 and 21 ± 0.15 mm against MRSA(ATCC 43300,700699) and 24 ± 0.05 mm for VRE with MIC of 6.25,3.125 and 1.56 μg/mL respectively. The MIC (Minimum inhibitory concentration) index further confirmed that both the extracts were bacteriostatic against MRSA and bactericidal against VRE. The isolates TPL11 and TPL14 were identified as Fusarium oxysporum and Nigrospora sphaerica by 18S rRNA internal transcribed spacer (ITS) sequencing. To our insight, it is the first report to reveal the presence of F.oxysporum and N.sphaerica in T.pallida and their antibacterial activity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Endophytes refer to microorganisms residing within the endosphere of plants, particularly perennials, without inflicting noticeable injury or inducing obvious morphological variations to their host ...plant or host organism. Endophytic fungi, although often overlooked microorganisms, have garnered interest due to their significant biological diversity and ability to produce novel pharmacological substances.
In this study, fourteen endophytic fungi retrieved were from the stem of the perennial plant
of the Asparagaceae family. These fungal crude metabolites were tested for antagonistic susceptibility to Multi-Drug Resistant (MDR) pathogens using agar well diffusion, Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) assays. The chequerboard test was used to assess the synergistic impact of active extract.
In early antibacterial screening using the Agar plug diffusion test, three of fourteen endophytes demonstrated antagonism against Methicillin-resistant
(MRSA) and Vancomycin-resistant
(VRE). Three isolates were grown in liquid medium and their secondary metabolites were recovered using various organic solvents. Eight extracts from three endophytic fungi displayed antagonism against one or more human pathogens with diameters ranging from 11 to 24 mm. The highest antagonistic effect was obtained in ethyl acetate extract for PTS8 isolate against two MRSA (ATCC 43300, 700699) with 20 ± 0.27 and 22 ± 0.47 mm zones of inhibition, respectively, among different solvent extracts. The extract had MICs of 3.12 ± 0.05 and 1.56 ± 0.05 μg/mL, and MBCs of 50 ± 0.01 and 12.5 ± 0.04 μg/mL, respectively. Antagonism against VRE was 18 ± 0.23 mm Zone of Inhibition (ZOI) with MIC and MBC of 6.25 ± 0.25 and 25 ± 0.01 μg/mL. When ethyl acetate extract was coupled with antibiotics, the chequerboard assay demonstrated a synergistic impact against MDR bacteria. In an antioxidant test, it had an inhibitory impact of 87 ± 0.5% and 88.5 ± 0.5% in 2,2-Diphenyl-1-Picrylhydrazyl and reducing power assay, respectively, at 150 μg/mL concentration. PTS8 was identified as a
strain by 18S rRNA internal transcribed spacer (ITS) sequencing. To our insight, it is the foremost study to demonstrate the presence of an
endophyte in the stem of P. tuberosa and the first report to study the antibacterial efficacy of
which might serve as a powerful antibacterial source against antibiotic-resistant human infections.
The present scenario of energy market is highly volatile due to large oscillation in the fossil fuel prices. During these periods, the high energy demand for the industries is being partially met ...through non-conventional energy sources such as wind and solar power. The large untapped energy potential in the Ocean is yet to be exploited due to many technological constraints. The recent decades have shown positive developments worldwide towards the ocean wave energy converters. In the present study, an improved wave energy potential estimate has been made. Based on various parameters such as physical site characteristics, environmental conditions and socio-economic regional state, the selection criteria have been suggested. This would form the basis for energy device selection for the decision makers.
•Re-assessment of wave energy potential along Indian coast has been made.•Device selection strategy is proposed based on energy potential, site characteristics and socio-economic aspects.•Few site specific devices have been recommended.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Microplastic particles are found in environmental compartments all over the world and receive a great deal of attention, especially in the aquatic environment. Currently, a particularly high input of ...microplastics via Asian rivers is assumed, but so far, there are hardly any data through field measurements. Three rivers in South India were considered for this purpose to focus on their microplastic load. The emphasis was on the comparison of microplastic concentrations in urban and rural rivers. While two rivers in the megacity Chennai (Tamil Nadu) were found to have an average microplastic concentration of 0.4 microplastic particles/L, a rural river near Munnar (Kerala) had an average concentration of 0.2 microplastic particles/L. Rough estimates of annual microplastic discharge from the Adyar River (Chennai) into the Bay of Bengal are found to be as high as 11.6 trillion microplastic particles. This study should be one of the first baseline studies for microplastic loads in South Indian streams and should be complemented with further environmental sampling before, during and after the monsoon season to get more detailed information on the storage and transportation of fluvial microplastics under different weather conditions.
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