114 research outputs found
Semi-automatic Design for Disassembly Strategy Planning: An Augmented Reality Approach
Abstract The mounting attention to environmental issues requires adopting better disassembly procedures at the product's End of Life. Planning and reckoning different disassembly strategies in the early stage of the design process can improve the development of sustainable products with an easy dismissing and recycling oriented approach. Nowadays many Computer Aided Process Planning software packages provide optimized assembly or disassembly sequences, but they are mainly based on a time and cost compression approach, neglecting the human factor. The environment we developed is based upon the integration of a CAD, an Augmented Reality tool, a Leap Motion Controller device, see-through glasses and an algorithm for disassembly strategies evaluation: this approach guarantees a more effective interaction with the 3D real and virtual assembly than an approach relying only on a CAD based disassembly sequence planning. In such a way, the operator may not test in a more natural and intuitive way automatic disassembly sequences, but he/she can also propose different strategies to improve the ergonomics. The methodology has been tested in a real case study to evaluate the strength points and criticalities of this approach
Leukocyte Integrin Antagonists as a Novel Option to Treat Dry Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a complex multifactorial degenerative disease
that leads to irreversible blindness. AMD affects the macula, the central part of the retina
responsible for sharp central vision. Retinal pigment epithelium (RPE) is the main cellular
type affected in dry AMD. RPE cells form a monolayer between the choroid and the
neuroretina and are in close functional relationship with photoreceptors; moreover, RPE
cells are part of the blood retina barrier that is disrupted in ocular diseases such as AMD.
During ocular inflammation lymphocytes and macrophages are recruited, contact RPE and
produce pro-inflammatory cytokines, which play an important role in AMD pathogenesis.
The interaction between RPE and immune cells is mediated by leukocyte integrins,
heterodimeric transmembrane receptors, and adhesion molecules, including VCAM-1
and ICAM-1. Within this frame, this study aimed to characterize RPE-leukocytes
interaction and to investigate any potentially beneficial effects induced by integrin
antagonists (DS-70, MN27 and SR714), developed in previous studies. ARPE-19 cells
were co-cultured for different incubation times with Jurkat cells and apoptosis and
necrosis levels were analyzed by flow cytometry. Moreover, we measured the mRNA
levels of the pro-inflammatory cytokine IL-1\u3b2 and the expression of adhesion molecules
VCAM-1 and ICAM-1. We found that RPE-lymphocyte interaction increased apoptosis
and necrosis levels in RPE cells and the expression of IL-1\u3b2. This interaction was mediated
by the binding of \u3b14\u3b21 and \u3b1L\u3b22 integrins to VCAM-1 and ICAM-1, respectively. The
blockade of RPE-lymphocyte interaction with blocking antibodies highlighted the pivotal
role played by integrins. Therefore, \u3b14\u3b21 and \u3b1L\u3b22 integrin antagonists were employed to
disrupt RPE-lymphocyte crosstalk. Small molecule integrin antagonists proved to be
effective in reducing RPE cell death and expression of IL-1\u3b2, demonstrating that integrin
antagonists could protect RPE cells from detrimental effects induced by the interaction
with immune cells recruited to the retina. Overall, the leukocyte integrin antagonists
employed in the present study may represent a novel opportunity to develop new
drugs to fight dry AMD
Enhanced expression of hepatic lipogenic enzymes in an animal model of sedentariness.
The hindlimb-suspended rat was used as animal model to investigate the effects induced by immobilization of the skeletal muscle in the expression of the genes encoding hepatic lipogenic enzymes. Following a 14-day period of immobilization, rats were injected intraperitoneally with radioactive acetate, and the labeling of hepatic lipids and cholesterol was evaluated 15 min after the isotope injection. The incorporation of labeled acetate in lipids and cholesterol was almost three times higher in the liver of immobilized rats than in control animals as a consequence of the enhanced transcription of the genes encoding acetyl-CoA synthase, acetyl-CoA carboxylase, fatty acid synthase, and 3-hydroxy-3-methylglutaryl-CoA reductase. The high expression of the key enzymes for fatty acid and cholesterol synthesis induced by immobilization was not paralleled by an increase of the hepatic sterol-regulatory element binding protein (SREBP)-1 and SREBP-2 mRNA content. However, the expression of the mature form of SREBP-1 and SREBP-2 was higher in the nuclear fraction of immobilized rat liver than in controls due to a significant increase of the cleavage of the native proteins. Immobilization also affected the expression of proteins involved in lipid degradation. In fact, the hepatic content of peroxisome proliferator-activated receptor-alpha (PPARalpha) mRNA and of PPARalpha target genes encoding carnitine palmitoyl transferase-1 and acyl-CoA oxidase were significantly increased upon immobilization
Assessment of Various Density Functionals and Basis Sets for the Calculation of Molecular Anharmonic Force Fields
In a previous contribution (Mol. Phys. {\bf 103}, xxxx, 2005), we established
the suitability of density functional theory (DFT) for the calculation of
molecular anharmonic force fields. In the present work, we have assessed a wide
variety of basis sets and exchange-correlation functionals for harmonic and
fundamental frequencies, equilibrium and ground-state rotational constants, and
thermodynamic functions beyond the RRHO (rigid rotor-harmonic oscillator)
approximation. The fairly good performance of double-zeta plus polarization
basis sets for frequencies results from an error compensation between basis set
incompleteness and the intrinsic error of exchange-correlation functionals.
Triple-zeta plus polarization basis sets are recommended, with an additional
high-exponent function on second-row atoms. All conventional hybrid GGA
functionals perform about equally well: high-exchange hybrid GGA and meta-GGA
functionals designed for kinetics yield poor results, with the exception of of
the very recently developed BMK functional which takes a middle position along
with the HCTH/407 (second generation GGA) and TPSS (meta-GGA) functionals. MP2
performs similarly to these functionals but is inferior to hybrid GGAs such as
B3LYP and B97-1.Comment: Int. J. Quantum Chem., in press (special issue on vibrational
spectroscopies
Il materiale didattico relativo al corso di Disegno tecnico industriale può essere reperito nel sito personale del Docente: http://diem1.ing.unibo.it/diem/cali/dticalimec.html
Il materiale didattico relativo al corso di Disegno assistito dal calcolatore può essere reperito nel sito personale del Docente: http://diem1.ing.unibo.it/diem/cali/CADkalienerg.htm
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