359 research outputs found
Stress concentration targeted reinforcement using multi-material based 3D printing
Topological engineering (3D printing into complex geometry) has emerged as a pragmatic approach to develop high specific strength (high strength and low density) lightweight structures. These complex lightweight structures fail at high-stress concentration regions, which can be, replaced with soft/tough material using 3D printing. It can improve mechanical properties such as strength, toughness and energy absorption etc. Here, we have developed stress concentration targeted multi-material schwarzite structures by 3D printing technique. The soft (Thermoplastic Polyurethane) material is reinforced at high-stress concentration regions of hard (Polylactic acid) schwarzite structures to enhance the specific yield strength and resilience. The mechanical properties and responses of these structures were then assessed via uniaxial compression tests. The multi-materials 3D printed composite structure shows improved mechanical properties compared to single materials architecture. The specific resilience of composites demonstrates remarkable enhancements, with percentage increases of 204.70 %, 596.50 %, and 1530.99 % observed when compared to hard primitives, and similarly impressive improvements of 182.45 %, 311.64 %, and 477.75 % observed in comparison to hard gyroids. The obtained experimental findings were comprehensively examined and validated with molecular dynamics (MD) simulations. The promising characteristics of these lightweight multi-material-based Schwarzites structures can be utilized in various fields such as energy harvesting devices, protective, safety gears, and aerospace components
Ferromagnetic phases in spin-Fermion systems
Spin-Fermion systems which obtain their magnetic properties from a system of
localized magnetic moments being coupled to conducting electrons are
considered. The dynamical degrees of freedom are spin- operators of
localized spins and spin-1/2 Fermi operators of itinerant electrons.
Renormalized spin-wave theory, which accounts for the magnon-magnon
interaction, and its extension are developed to describe the two ferrimagnetic
phases in the system: low temperature phase , where all electrons
contribute the ordered ferromagnetic moment, and high temperature phase
, where only localized spins form magnetic moment. The
magnetization as a function of temperature is calculated. The theoretical
predictions are utilize to interpret the experimentally measured
magnetization-temperature curves of ..Comment: 9 pages, 5 figure
Dilatometry study of the ferromagnetic order in single-crystalline URhGe
Thermal expansion measurements have been carried out on single-crystalline
URhGe in the temperature range from 2 to 200 K. At the ferromagnetic transition
(Curie temperature T_C = 9.7 K), the coefficients of linear thermal expansion
along the three principal orthorhombic axes all exhibit pronounced positive
peaks. This implies that the uniaxial pressure dependencies of the Curie
temperature, determined by the Ehrenfest relation, are all positive.
Consequently, the calculated hydrostatic pressure dependence dT_C/dp is
positive and amounts to 0.12 K/kbar. In addition, the effective Gruneisen
parameter was determined. The low-temperature electronic Gruneisen parameter
\Gamma_{sf} = 14 indicates an enhanced volume dependence of the ferromagnetic
spin fluctuations at low temperatures. Moreover, the volume dependencies of the
energy scales for ferromagnetic order and ferromagnetic spin fluctuations were
found to be identical.Comment: 5 page
Split transition in ferromagnetic superconductors
The split superconducting transition of up-spin and down-spin electrons on
the background of ferromagnetism is studied within the framework of a recent
model that describes the coexistence of ferromagnetism and superconductivity
induced by magnetic fluctuations. It is shown that one generically expects the
two transitions to be close to one another. This conclusion is discussed in
relation to experimental results on URhGe. It is also shown that the magnetic
Goldstone modes acquire an interesting structure in the superconducting phase,
which can be used as an experimental tool to probe the origin of the
superconductivity.Comment: REVTeX4, 15 pp, 7 eps fig
Iron under Earth's core conditions: Liquid-state thermodynamics and high-pressure melting curve
{\em Ab initio} techniques based on density functional theory in the
projector-augmented-wave implementation are used to calculate the free energy
and a range of other thermodynamic properties of liquid iron at high pressures
and temperatures relevant to the Earth's core. The {\em ab initio} free energy
is obtained by using thermodynamic integration to calculate the change of free
energy on going from a simple reference system to the {\em ab initio} system,
with thermal averages computed by {\em ab initio} molecular dynamics
simulation. The reference system consists of the inverse-power pair-potential
model used in previous work. The liquid-state free energy is combined with the
free energy of hexagonal close packed Fe calculated earlier using identical
{\em ab initio} techniques to obtain the melting curve and volume and entropy
of melting. Comparisons of the calculated melting properties with experimental
measurement and with other recent {\em ab initio} predictions are presented.
Experiment-theory comparisons are also presented for the pressures at which the
solid and liquid Hugoniot curves cross the melting line, and the sound speed
and Gr\"{u}neisen parameter along the Hugoniot. Additional comparisons are made
with a commonly used equation of state for high-pressure/high-temperature Fe
based on experimental data.Comment: 16 pages including 6 figures and 5 table
Heat-capacity anomalies at and in the ferromagnetic superconductor UGe
The heat-capacity and magnetization measurements under high pressure have
been carried out in a ferromagnetic superconductor UGe. Both measurements
were done using a same pressure cell in order to obtain both data for one
pressure. Contrary to the heat capacity at ambient pressure, an anomaly is
found in the heat capacity at the characteristic temperature where the
magnetization shows an anomalous enhancement under high pressure where the
superconductivity appears. This suggests that a thermodynamic phase transition
takes place at at least under high pressure slightly below
where becomes zero. The heat-capacity anomaly associated with the
superconducting transition is also investigated, where a clear peak of is
observed in a narrow pressure region ( GPa) around
contrary to the previous results of the resistivity measurement.
Present results suggest the importance of the thermodynamic critical point
for the appearance of the superconductivity.Comment: 4 pages, 4 figures, to appear in Phys. Rev. B, Rapid Communication
The global, regional, and national burden of inflammatory bowel disease in 195 countries and territories, 1990-2017 : a systematic analysis for the Global Burden of Disease Study 2017
Background The burden of inflammatory bowel disease (IBD) is rising globally, with substantial variation in levels and trends of disease in different countries and regions. Understanding these geographical differences is crucial for formulating effective strategies for preventing and treating IBD. We report the prevalence, mortality, and overall burden of IBD in 195 countries and territories between 1990 and 2017, based on data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017. Methods We modelled mortality due to IBD using a standard Cause of Death Ensemble model including data mainly from vital registrations. To estimate the non-fatal burden, we used data presented in primary studies, hospital discharges, and claims data, and used DisMod-MR 2.1, a Bayesian meta-regression tool, to ensure consistency between measures. Mortality, prevalence, years of life lost (YLLs) due to premature death, years lived with disability (YLDs), and disability-adjusted life-years (DALYs) were estimated. All of the estimates were reported as numbers and rates per 100 000 population, with 95% uncertainty intervals (UI). Findings In 2017, there were 6.8 million (95% UI 6.4-7.3) cases of IBD globally. The age-standardised prevalence rate increased from 79.5 (75.9-83.5) per 100 000 population in 1990 to 84.3 (79.2-89.9) per 100 000 population in 2017. The age-standardised death rate decreased from 0.61 (0.55-0.69) per 100 000 population in 1990 to 0.51 (0.42-0.54) per 100 000 population in 2017. At the GBD regional level, the highest age-standardised prevalence rate in 2017 occurred in high-income North America (422.0 [398.7-446.1] per 100 000) and the lowest age-standardised prevalence rates were observed in the Caribbean (6.7 [6.3-7.2] per 100 000 population). High Sociodemographic Index (SDI) locations had the highest age-standardised prevalence rate, while low SDI regions had the lowest age-standardised prevalence rate. At the national level, the USA had the highest age-standardised prevalence rate (464.5 [438.6-490.9] per 100 000 population), followed by the UK (449.6 [420.6-481.6] per 100 000). Vanuatu had the highest age-standardised death rate in 2017 (1.8 [0.8-3.2] per 100 000 population) and Singapore had the lowest (0.08 [0.06-0.14] per 100 000 population). The total YLDs attributed to IBD almost doubled over the study period, from 0.56 million (0.39-0.77) in 1990 to 1.02 million (0.71-1.38) in 2017. The age-standardised rate of DALYs decreased from 26.5 (21.0-33.0) per 100 000 population in 1990 to 23.2 (19.1-27.8) per 100 000 population in 2017. Interpretation The prevalence of IBD increased substantially in many regions from 1990 to 2017, which might pose a substantial social and economic burden on governments and health systems in the coming years. Our findings can be useful for policy makers developing strategies to tackle IBD, including the education of specialised personnel to address the burden of this complex disease. Copyright (C) 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe
The global, regional, and national burden of inflammatory bowel disease in 195 countries and territories, 1990�2017: a systematic analysis for the Global Burden of Disease Study 2017
Background: The burden of inflammatory bowel disease (IBD) is rising globally, with substantial variation in levels and trends of disease in different countries and regions. Understanding these geographical differences is crucial for formulating effective strategies for preventing and treating IBD. We report the prevalence, mortality, and overall burden of IBD in 195 countries and territories between 1990 and 2017, based on data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017. Methods: We modelled mortality due to IBD using a standard Cause of Death Ensemble model including data mainly from vital registrations. To estimate the non-fatal burden, we used data presented in primary studies, hospital discharges, and claims data, and used DisMod-MR 2.1, a Bayesian meta-regression tool, to ensure consistency between measures. Mortality, prevalence, years of life lost (YLLs) due to premature death, years lived with disability (YLDs), and disability-adjusted life-years (DALYs) were estimated. All of the estimates were reported as numbers and rates per 100 000 population, with 95 uncertainty intervals (UI). Findings: In 2017, there were 6·8 million (95 UI 6·4�7·3) cases of IBD globally. The age-standardised prevalence rate increased from 79·5 (75·9�83·5) per 100 000 population in 1990 to 84·3 (79·2�89·9) per 100 000 population in 2017. The age-standardised death rate decreased from 0·61 (0·55�0·69) per 100 000 population in 1990 to 0·51 (0·42�0·54) per 100 000 population in 2017. At the GBD regional level, the highest age-standardised prevalence rate in 2017 occurred in high-income North America (422·0 398·7�446·1 per 100 000) and the lowest age-standardised prevalence rates were observed in the Caribbean (6·7 6·3�7·2 per 100 000 population). High Socio-demographic Index (SDI) locations had the highest age-standardised prevalence rate, while low SDI regions had the lowest age-standardised prevalence rate. At the national level, the USA had the highest age-standardised prevalence rate (464·5 438·6�490·9 per 100 000 population), followed by the UK (449·6 420·6�481·6 per 100 000). Vanuatu had the highest age-standardised death rate in 2017 (1·8 0·8�3·2 per 100 000 population) and Singapore had the lowest (0·08 0·06�0·14 per 100 000 population). The total YLDs attributed to IBD almost doubled over the study period, from 0·56 million (0·39�0·77) in 1990 to 1·02 million (0·71�1·38) in 2017. The age-standardised rate of DALYs decreased from 26·5 (21·0�33·0) per 100 000 population in 1990 to 23·2 (19·1�27·8) per 100 000 population in 2017. Interpretation: The prevalence of IBD increased substantially in many regions from 1990 to 2017, which might pose a substantial social and economic burden on governments and health systems in the coming years. Our findings can be useful for policy makers developing strategies to tackle IBD, including the education of specialised personnel to address the burden of this complex disease. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
Meta-analysis of type 2 Diabetes in African Americans Consortium
Type 2 diabetes (T2D) is more prevalent in African Americans than in Europeans. However, little is known about the genetic risk in African Americans despite the recent identification of more than 70 T2D loci primarily by genome-wide association studies (GWAS) in individuals of European ancestry. In order to investigate the genetic architecture of T2D in African Americans, the MEta-analysis of type 2 DIabetes in African Americans (MEDIA) Consortium examined 17 GWAS on T2D comprising 8,284 cases and 15,543 controls in African Americans in stage 1 analysis. Single nucleotide polymorphisms (SNPs) association analysis was conducted in each study under the additive model after adjustment for age, sex, study site, and principal components. Meta-analysis of approximately 2.6 million genotyped and imputed SNPs in all studies was conducted using an inverse variance-weighted fixed effect model. Replications were performed to follow up 21 loci in up to 6,061 cases and 5,483 controls in African Americans, and 8,130 cases and 38,987 controls of European ancestry. We identified three known loci (TCF7L2, HMGA2 and KCNQ1) and two novel loci (HLA-B and INS-IGF2) at genome-wide significance (4.15 × 10(-94)<P<5 × 10(-8), odds ratio (OR) = 1.09 to 1.36). Fine-mapping revealed that 88 of 158 previously identified T2D or glucose homeostasis loci demonstrated nominal to highly significant association (2.2 × 10(-23) < locus-wide P<0.05). These novel and previously identified loci yielded a sibling relative risk of 1.19, explaining 17.5% of the phenotypic variance of T2D on the liability scale in African Americans. Overall, this study identified two novel susceptibility loci for T2D in African Americans. A substantial number of previously reported loci are transferable to African Americans after accounting for linkage disequilibrium, enabling fine mapping of causal variants in trans-ethnic meta-analysis studies.Peer reviewe
Pigeonpea nutrition and its improvement
Pigeonpea (Cajanus cajan [L.] Millsp.), known by several
vernacular and names such as red gram, tuar, Angola
pea. yellow dhal and oil dhal, is one of the major grain legume crops of
the tropics and sub-tropics. It is a crop of small holder dryland
fmmers because it can grow well under subsistence level of agriculture
and provides nutritive food, fodder, and fuel wood. It also improves soil
by fixing atmospheric nitrogen. India by far is the largest pigeonpea producer
it is consumed as decorticated split peas, popularly called as
'dhaL' In other countries, its consumption as whole dty and green
vegetable is popular. Its foliage is used as fodder and milling by-products
[onn an excellent feed for domestic animals. Pigeonpea seeds contain
about 20-22% protein and appreciable amounts of essential amino.acids
and minerals. DehuHing and boiling treatments of seeds get rid of the
most antinutritional factors as tannins and enzyme inhibitors. Seed
storage causes considerable losses in the quality of this legume. The seed
protein of pigeonpea has been successfully enhanced by breeding from
20-22% to 28-30%. Such lines also agronomically performed well and
have acceptable and color. The high-protein lines were found nutritionally superior to the cultivars because they would provide more
quantities of utilizable protein and sulfur-containing amino acids
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