Dynamic response of a linear two d.o.f system visco-elastically coupled with a rigid block

Di Egidio, Angelo,Pagliaro, Stefano,Fabrizio, Cristiano,de Leo, Andrea M. Techno-Press 2019 Coupled systems mechanics Vol.8 No.4

The present work investigates the use of a rigid rocking block as a tool to reduce vibrations in a frame structure. The study is based on a simplified model composed by a 2-DOF linear system, meant to represent a general M-DOF frame structure, coupled with a rocking rigid block through a linear visco-elastic device, which connects only the lower part of the 2-DOF system. The possibility to restrain the block directly to the ground, by means of a second visco-elastic device, is investigated as well. The dynamic response of the model under an harmonic base excitation is then analysed in order to evaluate the effectiveness of the coupling in reducing the displacements and the drift of the 2-DOF system. The nonlinear equations of motion of the coupled assemblage 2-DOF-block are obtained by a Lagrangian approach and then numerically integrated considering some reference mechanical and geometrical quantities as variable parameters. It follows an extensive parametric analysis, whose results are summarized through behaviour maps, which portray the ratio between the maximum displacements and drifts of the system, with and without the coupling with the rigid block, for several combinations of system's parameters. When the ratio of the displacements is less than unity, the coupling is considered effective. Results show that the presence of the rocking rigid block improves the dynamics of the system in large ranges of the characterizing parameters.

Atomistic modelling of the hypervelocity dynamics of shock-compressed graphite and impacted graphene armours

Signetti, Stefano,Kang, Keonwook,Pugno, Nicola M.,Ryu, Seunghwa Elsevier 2019 Computational materials science Vol.170 No.-

<P><B>Abstract</B></P> <P>We present a molecular dynamics (MD) simulation study on the hypervelocity dynamics of shock compressed graphite -up to hundreds of gigapascals- and impacted multilayer graphene armours by employing the AIREBO-M potential. The Morse-type non-singular intermolecular interaction allows the usage of relatively large integration timesteps for simulating materials’ response at such high strain-rate. The MD simulation results are in good agreement with the shock Hugoniot curves and with graphite-to-diamond transition obtained from both density functional theory (DFT) and experiments available in literature. We then show that thermodynamic properties of graphite from MD calculations can be used as input for a reliable equation of state to be employed in continuum simulations. Finally, we find that the size-scaling of the hypervelocity impact properties of graphene armours matches well with the DFT results and theoretical predictions of earlier studies. Our results open a concrete possibility towards accurate and fast multiscale simulation from atomistic to continuum level of shock propagation, shock-induced phase transformation, and dynamic fracture in large or hierarchical carbon systems, such as graphene-based foams and nanocomposites.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Steroids in the Management of Preoperative Neurological Deficits in Metastatic Spine Disease: Results From the EPOSO Study

Anne L. Versteeg,Lior M. Elkaim,Arjun Sahgal,Laurence D. Rhines,Daniel M. Sciubba,James M. Schuster,Michael G. Fehlings,Aron Lazary,Michelle J. Clarke,Paul M. Arnold,Chetan Bettegowda,Stefano Boriani 대한척추신경외과학회 2022 Neurospine Vol.19 No.1

Objective: Patients presenting with neurological deficit secondary to metastatic epidural spinal cord compression (MESCC) are often treated with surgery in combination with high-dose corticosteroids. Despite steroids being commonly used, the evidence regarding the effect of corticosteroids on patient outcomes is limited. The objective of this study was to describe the effect of corticosteroid use on preoperative neurological function in patients with MESCC. Methods: Patients who underwent surgery between August 2013 and February 2017 for the treatment of spinal metastases and received steroids to prevent neurologic deficits were included. Data regarding demographics, diagnosis, treatment, neurological function, adverse events, health-related quality of life, and survival were extracted from an international multicenter prospective cohort. Results: A total of 30 patients treated surgically and receiving steroids at baseline were identified. Patients had a mean age of 58.2 years (standard deviation, 11.2 years) at time of surgery. Preoperatively, 50% of the patients experienced deterioration of neurological function, while in 30% neurological function was stable and 20% improved in neurological function. Lengthier steroid use did not correlate with improved or stabilized neurological function. Postoperative adverse events were observed in 18 patients (60%). Patients that stabilized or improved neurologically after steroid use showed a trend towards improved survival at 3- and 24-month postsurgery. Conclusion: This study described the effect of steroids on preoperative neurological function in patients with MESCC. Stabilization or improvement of preoperative neurological function occurred in 50% of the patients.

The Italian Association of Radiotherapy and Oncology Recommendation for Breast Tumor Recurrence: Grades of Recommendation, Assessment, Development and Evaluation Criteria

Marta Bottero,Valentina Borzillo,Stefano Pergolizzi,Barbara Alicja Jereczek-Fossa,Edy Ippolito,Giovanni Piero Frezza,Lucio Fortunato,Renzo Corvò,Giovanni Luigi Pappagallo,Stefano Arcangeli,Stefano M. 한국유방암학회 2021 Journal of breast cancer Vol.24 No.3

Salvage mastectomy is currently considered the standard of care for ipsilateral breast tumor recurrence (IBTR) after breast-conserving surgery (BCS) and postoperative radiotherapy (RT). Alternative treatment options for these patients, such as a second BCS followed by repeated RT, have been suggested. The panel of the Italian Association of Radiotherapy and Clinical Oncology developed clinical recommendations for second BCS followed by re-irradiation over mastectomy alone for women with IBTR using the Grades of Recommendation, Assessment, Development, and Evaluation methodology and the evidence to decision framework. The following outcomes were identified by the panel: locoregional control, metastasis-free survival, overall survival, and cancer-specific survival; acute and late toxicity, specific late toxicity, second locoregional tumor, and death related to treatment. An Embase and PubMed literature search was performed by two independent authors. Five retrospective observational studies were eligible for inclusion in the present analysis. According to the reports in the literature and our analysis, the advantages of second quadrantectomy and re-irradiation (re-QUART) outweigh its side effects, with overall good rates of survival and adequate toxicity without increasing costs. Given the very low level of evidence, the panel stated that a second BCS plus re-irradiation can be considered as an alternative to salvage mastectomy for selected patients with IBTR.

Analysis of traditional Chinese anticancer drugs by capillary electrophoresis

Liebich, H.M.,Lehmann, R.,Stefano, Di C.,Ha¨ring, H.U.,Kim, J.H.,Kim, K.R. 성균관대학교 약학연구소 1998 成均藥硏論文集 Vol.10 No.1

The results reported in this communication demonstrate that capillary zone electrophoresis (CZE) can be used easily for the quantitative determination of the potential anticancer drugs berberine and isoguanosine in the extract of the traditional Chinese medicinal herb. Isoguanosine and berberine can be montitored selectively and sensitively at 254 nm within 14 min in the plant extract using a 100-mM sodium citrate running buffer (adjusted to pH 2.7; applied voltage 12 kV). The concentration range of 0.1-50㎍ ㎖^-1 proved to be sufficient for exact quantification and the peak profile showed good reproducibility [relative standard deviations(n=32): for the migration time 0.22% (isoguanosine) and 1.32% (berberine); for the peak area 2.8% (isoguanosine) and 3.2% (berberine)]. The measured concentrations in the crude extract were 1.3㎍ ㎖^-1 for isoguanosine and 8.7 ㎍ ㎖^-1 for berberine. In addition to the better separation performance, CZE shows several other remarkable advantages over high-performance liquid chromatography (HPLC), such as rapidity of analysis, small sample volume, no requirement of organic solvent in the running buffer and low cost of reagents.

Ultrasound and clinical findings from metacarpophalangeal joint assessments in show jumping horses in training

Ana Lúcia M. Yamada,Marcelo Pinheiro,Marília F. Marsiglia,Stefano Carlo F. Hagen,Raquel Yvonne A. Baccarin,Luís Cláudio L. C. da Silva 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.3

The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound foBackground: Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management. Objectives: The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals. Methods: A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses’ athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months. Results: The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study. Conclusions: The observed results were probably caused by the implementation of a traininBackground: Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management. Objectives: The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals. Methods: A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses’ athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months. Results: The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study. Conclusions: The observed results were probably caused by the implementation of a training regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential. g regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential.llow-ups of metacarpophalangeal joint changes in these animals....

Functional Diversity of Cysteine Residues in Proteins and Unique Features of Catalytic Redox-active Cysteines in Thiol Oxidoreductases

Dmitri E. Fomenko,Stefano M. Marino,Vadim N. Gladyshev 한국분자세포생물학회 2008 Molecules and cells Vol.26 No.3

Thiol-dependent redox systems are involved in regulation of diverse biological processes, such as response to stress, signal transduction, and protein folding. The thiol-based redox control is provided by mechanistically similar, but structurally distinct families of enzymes known as thiol oxidoreductases. Many such enzymes have been characterized, but identities and functions of the entire sets of thiol oxidoreductases in organisms are not known. Extreme sequence and structural divergence makes identification of these proteins difficult. Thiol oxidoreductases contain a redox-active cysteine residue, or its functional analog selenocysteine, in their active sites. Here, we describe computational methods for in silico prediction of thiol oxidoreductases in nucleotide and protein sequence databases and identification of their redox-active cysteines. We discuss different functional categories of cysteine residues, describe methods for discrimination between catalytic and noncatalytic and between redox and non-redox cysteine residues and highlight unique properties of the redox-active cysteines based on evolutionary conservation, secondary and three-dimensional structures, and sporadic replacement of cysteines with catalytically superior selenocysteine residues.

Ultrasound and clinical findings in the metacarpophalangeal joint assessment of show jumping horses in training

Yamada, Ana Lucia M.,Pinheiro, Marcelo,Marsiglia, Marilia F.,Hagen, Stefano Carlo F.,Baccarin, Raquel Yvonne A.,da Silva, Luis Claudio L.C. The Korean Society of Veterinary Science 2020 JOURNAL OF VETERINARY SCIENCE Vol.21 No.2

Background: Physical exercise is known to cause significant joint changes. Thus, monitoring joint behavior of athletic horses is essential in early disorders recognition, allowing the proper management. Objectives: The aims of this study were to determine the morphological patterns, physical examination characteristics and ultrasound findings of show jumping horses in training and to establish a score-based examination model for physical and ultrasound follow-ups of metacarpophalangeal joint changes in these animals. Methods: A total of 52 metacarpophalangeal joints from 26 horses who were initially in the taming stage were evaluated, and the horses' athletic progression was monitored. The horses were evaluated by a physical examination and by B-mode and Doppler-mode ultrasound examinations, starting at time zero (T0), which occurred concomitantly with the beginning of training, and every 3 months thereafter for a follow-up period of 18 months. Results: The standardized examination model revealed an increase in the maximum joint flexion angles and higher scores on the physical and ultrasound examinations after scoring was performed by predefined assessment tools, especially between 3 and 6 months of evaluation, which was immediately after the horses started more intense training. The lameness score and the ultrasound examination score were slightly higher at the end of the study. Conclusions: The observed results were probably caused by the implementation of a training regimen and joint adaptation to physical conditioning. The joints most likely undergo a pre-osteoarthritic period due to work overload, which can manifest in a consistent or adaptive manner, as observed during this study. Thus, continuous monitoring of young athlete horses by physical and ultrasound examinations that can be scored is essential.

Deep learning approach for the segmentation of aneurysmal ascending aorta

Albert Comelli,Navdeep Dahiya,Alessandro Stefano,Viviana Benfante,Giovanni Gentile,Valentina Agnese,Giuseppe M. Raffa,Michele Pilato,Anthony Yezzi,Giovanni Petrucci,Salvatore Pasta 대한의용생체공학회 2021 Biomedical Engineering Letters (BMEL) Vol.11 No.1

Diagnosis of ascending thoracic aortic aneurysm (ATAA) is based on the measurement of the maximum aortic diameter,but size is not a good predictor of the risk of adverse events. There is growing interest in the development of novel imagederivedrisk strategies to improve patient risk management towards a highly individualized level. In this study, the feasibilityand efficacy of deep learning for the automatic segmentation of ATAAs was investigated using UNet, ENet, and ERFNettechniques. Specifically, CT angiography done on 72 patients with ATAAs and different valve morphology (i.e., tricuspidaortic valve, TAV, and bicuspid aortic valve, BAV) were semi-automatically segmented with Mimics software (MaterializeNV, Leuven, Belgium), and then used for training of the tested deep learning models. The segmentation performance interms of accuracy and time inference were compared using several parameters. All deep learning models reported a dicescore higher than 88%, suggesting a good agreement between predicted and manual ATAA segmentation. We found that theENet and UNet are more accurate than ERFNet, with the ENet much faster than UNet. This study demonstrated that deeplearning models can rapidly segment and quantify the 3D geometry of ATAAs with high accuracy, thereby facilitating theexpansion into clinical workflow of personalized approach to the management of patients with ATAAs.

Functional Analysis of Free Methionine-<i>R</i>-sulfoxide Reductase from<i>Saccharomyces cerevisiae</i>

Le, Dung Tien,Lee, Byung Cheon,Marino, Stefano M.,Zhang, Yan,Fomenko, Dmitri E.,Kaya, Alaattin,Hacioglu, Elise,Kwak, Geun-Hee,Koc, Ahmet,Kim, Hwa-Young,Gladyshev, Vadim N. American Society for Biochemistry and Molecular Bi 2009 The Journal of biological chemistry Vol.284 No.7

<P>Methionine sulfoxide reductases (Msrs) are oxidoreductases that catalyze thiol-dependent reduction of oxidized methionines. MsrA and MsrB are the best known Msrs that repair methionine-S-sulfoxide (Met-S-SO) and methionine-R-sulfoxide (Met-R-SO) residues in proteins, respectively. In addition, an Escherichia coli enzyme specific for free Met-R-SO, designated fRMsr, was recently discovered. In this work, we carried out comparative genomic and experimental analyses to examine occurrence, evolution, and function of fRMsr. This protein is present in single copies and two mutually exclusive subtypes in about half of prokaryotes and unicellular eukaryotes but is missing in higher plants and animals. A Saccharomyces cerevisiae fRMsr homolog was found to reduce free Met-R-SO but not free Met-S-SO or dabsyl-Met-R-SO. fRMsr was responsible for growth of yeast cells on Met-R-SO, and the double fRMsr/MsrA mutant could not grow on a mixture of methionine sulfoxides. However, in the presence of methionine, even the triple fRMsr/MsrA/MsrB mutant was viable. In addition, fRMsr deletion strain showed an increased sensitivity to oxidative stress and a decreased life span, whereas overexpression of fRMsr conferred higher resistance to oxidants. Molecular modeling and cysteine residue targeting by thioredoxin pointed to Cys(101) as catalytic and Cys(125) as resolving residues in yeast fRMsr. These residues as well as a third Cys, resolving Cys(91), clustered in the structure, and each was required for the catalytic activity of the enzyme. The data show that fRMsr is the main enzyme responsible for the reduction of free Met-R-SO in S. cerevisiae.</P>