Material flow during the extrusion of simple and complex cross-sections using FEM

This paper deals with the extrusion of rod and shape sections and uses a 3D finite element model analysis (FEM) to predict the effect of die geometry on maximum extrusion load. A description of material flow in the container is considered in more detail for rod and shape sections in order to fully comprehend the transient conditions occurring during the process cycle. A comparison with experiments is made to assess the relative importance of some extrusion parameters in the extrusion process and to ensure that the numerical discretisation yields a realistic simulation of the process. The usefulness and the limitation of FEM are discussed when modelling complex shapes. Results are presented for velocity contours and shear stress distribution during the extrusion process. It is shown that for most of the shapes investigated, the material making up the extrudate cross-sections originates from differing regions of virgin material within the billet. The outside surface of the extrudate originates from the material moving along the dead metal zone (DMZ) and the core of the extrudate from the central deformation zone. The FE program appears to predict all the major characteristics of the flow observed macroscopically

Material flow during the extrusion of simple and complex cross-sections using FEM

This paper deals with the extrusion of rod and shape sections and uses a 3D finite element model analysis (FEM) to predict the effect of die geometry on maximum extrusion load. A description of material flow in the container is considered in more detail for rod and shape sections in order to fully comprehend the transient conditions occurring during the process cycle. A comparison with experiments is made to assess the relative importance of some extrusion parameters in the extrusion process and to ensure that the numerical discretisation yields a realistic simulation of the process. The usefulness and the limitation of FEM are discussed when modelling complex shapes. Results are presented for velocity contours and shear stress distribution during the extrusion process. It is shown that for most of the shapes investigated, the material making up the extrudate cross-sections originates from differing regions of virgin material within the billet. The outside surface of the extrudate originates from the material moving along the dead metal zone (DMZ) and the core of the extrudate from the central deformation zone. The FE program appears to predict all the major characteristics of the flow observed macroscopically

Evaluation of Low Bone Mineral Mass Using a Combination of Peripheral Bone Mineral Density and Total Body Composition Variables by Neural Network

AbstractThe aim of this work was to evaluate low bone mass using the feed-forward neural network (NN) with good accuracy taking into account the forearm and heel bone mineral density (BMD) as well as total body composition variables. A total number of 162 subjects including 88 women (mean ± SD age = 37.7 ± 15.2 years) and 74 men (mean ± SD age=31.3 ± 10.9 years) were studied. In each subject, BMD (g cm-2) at forearm and heel using peripheral dual-energy X-ray absorptiometry (pDXA) and total body composition variables by multifrequency bioelectrical impedance analyzer were measured. The measured forearm BMD was used to estimate femur neck BMD by DXA using the published formula. Based on its T-score value, subjects were classified as normal and low bone mineral mass groups separately. In women, it was found that the forearm BMD was positively correlated with body fat percentage (r=0.327; p<0.001). It was observed that 27% of women and 15% of men were affected by low bone mass. In the NN modelling, the following 10 measured variables were used in men and women separately: i) BMI ((kg/m2); ii) average forearm BMD (g/cm2); iii) average heel BMD (g/cm2); iv) body fat (%); v) muscle mass (kg); vi) visceral fat index; vii) bone mineral mass (kg); viii) total body water, TBW (%); ix) basal metabolic rate, BMR (kCal); and x) metabolic age (years). Analysis of low bone mineral mass evaluation using NN projected an accuracy of 87.5% and 85.1% in women and men population, respectively. With the aid of BMD at peripheral skeletal sites and total body composition variables, low bone mass can be evaluated with good accuracy

Culture of micro-organisms on cellophone membrane

This article does not have an abstract

Investigations on the absorption spectrum of TiO2 nanofluid

Nanofluids are tailored nano- colloidal suspensions of nanoparticles in a suitable base fluid. This present work investigates the absorption spectrum in TiO2-water nanofluids to identify the potential application of nanofluids in Direct Absorption Solar Collectors (DASC). Nanoparticles of Titanium dioxide (TiO2) are prepared by sol gel and characterized by X Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). TiO2-water nanofluids with weight fraction of 0.1% are prepared by a two-step process with sonication. The prepared nanofluids are investigated for their stability by a gravity sedimentation method and for their optical property by UV-Vis spectroscopy. Stability of nanofluid is essential for the applications of nanofluid in DASC. TiO2 nanoparticles with a crystallite size of 43nm are obtained .The SEM image reveals the agglomerated state of TiO2 nanoparticles and the stability of TiO2 nanofluid is reported as 9-10days. UV results indicate the decrease in absorption from 440-500nm, complete absorption from 500-700nm and increase in absorption from 700-900nm.TiO2 nanofluids are recommended as potential candidates for DASC in UV and IR regions

Compartmentalized Metabolic Engineering for Artemisinin Biosynthesis and Effective Malaria Treatment by Oral Delivery of Plant Cells

Artemisinin is highly effective against drug-resistant malarial parasites, which affects nearly half of the global population and kills \u3e500 000 people each year. The primary cost of artemisinin is the very expensive process used to extract and purify the drug from Artemisia annua. Elimination of this apparently unnecessary step will make this potent antimalarial drug affordable to the global population living in endemic regions. Here we reported the oral delivery of a non-protein drug artemisinin biosynthesized (~0.8 mg/g dry weight) at clinically meaningful levels in tobacco by engineering two metabolic pathways targeted to three different cellular compartments (chloroplast, nucleus, and mitochondria). The doubly transgenic lines showed a three-fold enhancement of isopentenyl pyrophosphate, and targeting AACPR, DBR2, and CYP71AV1 to chloroplasts resulted in higher expression and an efficient photo-oxidation of dihydroartemisinic acid to artemisinin. Partially purified extracts from the leaves of transgenic tobacco plants inhibited in vitro growth progression of Plasmodium falciparum-infected red blood cells. Oral feeding of whole intact plant cells bioencapsulating the artemisinin reduced the parasitemia levels in challenged mice in comparison with commercial drug. Such novel synergistic approaches should facilitate low-cost production and delivery of artemisinin and other drugs through metabolic engineering of edible plants

Crush characteristics and energy absorption of thin-walled tubes with through-hole crush initiators

An experimental investigation was conducted to compare the crush characteristics and energy absorption capacity of circular and square tubes with located through-hole crush initiator. Circular through-holes were fabricated at three different configurations based on location into steel tubes which had a length of 200 mm. Furthermore, two different side configurations along the tube were considered for introducing the crush initiators. The results found that adding crush initiator onto the tubes effectively reduced the initial peak force of a thin-walled circular and square tubes under axial quasi-static loading. The peak crush force was reduced within a range 3-10% and 5-16% for circular and square tubes, respectively when compared with corresponding tubes without crush initiator. Moreover, the energy absorption capacity of the tubes was independent with the incorporation of through-hole crush initiators. However, the energy absorption of circular and square tubes slightly decreases when compared with the tubes fabricated four sided crush initiation and tubes without crush initiator. Overall, the effect of location and number of crush initiation significantly influenced the initial peak forces while maintain the energy absorbed

Phase Transitions and Their Interaction with Dislocations in Silicon

In this paper, phase transformations (PTs) in silicon were investigated through molecular dynamics (MD) using Tersoff potential. In the first step, simulations of PTs in single crystal silicon under various stress-controlled loading were carried out. Results shows that all instability points under various stress states are described by criteria, which are linear in the space of normal stresses. There is a region in the stress space in which conditions for direct and reverse PTs coincide and a unique homogeneous phase transition (without nucleation) can be realized. Finally, phase transition in bi-crystalline silicon with a dislocation pileup along the grain boundary (GB) was carried out. Results showed that the phase transition pressure first decreases linearly with the number of dislocation pileups and then reaches a plateau with the accumulation of dislocations in the pileup. The maximum reduction of phase transition pressure is 30% compared to that for perfect single crystalline silicon

The CXCR4-LASP1-eIF4F Axis Promotes Translation of Oncogenic Proteins in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) remains clinically challenging as effective targeted therapies are lacking. In addition, patient mortality mainly results from the metastasized lesions. CXCR4 has been identified to be one of the major chemokine receptors involved in breast cancer metastasis. Previously, our lab had identified LIM and SH3 Protein 1 (LASP1) to be a key mediator in CXCR4-driven invasion. To further investigate the role of LASP1 in this process, a proteomic screen was employed and identified a novel protein-protein interaction between LASP1 and components of eukaryotic initiation 4F complex (eIF4F). We hypothesized that activation of the CXCR4-LASP1-eIF4F axis may contribute to the preferential translation of oncogenic mRNAs leading to breast cancer progression and metastasis. To test this hypothesis, we first confirmed that the gene expression of CXCR4, LASP1, and eIF4A are upregulated in invasive breast cancer. Moreover, we demonstrate that LASP1 associated with eIF4A in a CXCL12-dependent manner via a proximity ligation assay. We then confirmed this finding, and the association of LASP1 with eIF4B via co-immunoprecipitation assays. Furthermore, we show that LASP1 can interact with eIF4A and eIF4B through a GST-pulldown approach. Activation of CXCR4 signaling increased the translation of oncoproteins downstream of eIF4A. Interestingly, genetic silencing of LASP1 interrupted the ability of eIF4A to translate oncogenic mRNAs into oncoproteins. This impaired ability of eIF4A was confirmed by a previously established 5′UTR luciferase reporter assay. Finally, lack of LASP1 sensitizes 231S cells to pharmacological inhibition of eIF4A by Rocaglamide A as evident through BIRC5 expression. Overall, our work identified the CXCR4-LASP1 axis to be a novel mediator in oncogenic protein translation. Thus, our axis of study represents a potential target for future TNBC therapies

Development of a new drug candidate for the inhibition of Lassa virus glycoprotein and nucleoprotein by modification of evodiamine as promising therapeutic agents

The Lassa virus (LASV), an RNA virus prevalent in West and Central Africa, causes severe hemorrhagic fever with a high fatality rate. However, no FDA-approved treatments or vaccines exist. Two crucial proteins, LASV glycoprotein and nucleoprotein, play vital roles in pathogenesis and are potential therapeutic targets. As effective treatments for many emerging infections remain elusive, cutting-edge drug development approaches are essential, such as identifying molecular targets, screening lead molecules, and repurposing existing drugs. Bioinformatics and computational biology expedite drug discovery pipelines, using data science to identify targets, predict structures, and model interactions. These techniques also facilitate screening leads with optimal drug-like properties, reducing time, cost, and complexities associated with traditional drug development. Researchers have employed advanced computational drug design methods such as molecular docking, pharmacokinetics, drug-likeness, and molecular dynamics simulation to investigate evodiamine derivatives as potential LASV inhibitors. The results revealed remarkable binding affinities, with many outperforming standard compounds. Additionally, molecular active simulation data suggest stability when bound to target receptors. These promising findings indicate that evodiamine derivatives may offer superior pharmacokinetics and drug-likeness properties, serving as a valuable resource for professionals developing synthetic drugs to combat the Lassa virus