186 research outputs found
Effects of environment and stress concentration factor on Ti-6Al-4V specimens subjected to quasi-static loading
Abstract The bimodal titanium alloy Ti-6Al-4V is a well-known high strength-to-mass ratio material in different engineering sectors. Furthermore, the rapid oxidation of the surface protects the base material from the interaction with a wide spectrum of corrosive environments. However, the presence of surface defects and the mechanical loading may compromise the effectiveness of the oxide film. Quasi-static loading tests were carried out on different smooth and notched Ti-6Al-4V specimens in order to analyze the role of environment and stress concentration factor
Study and modelling of the passenger safety devices of an electric vehicle by finite elements
Abstract Electric mobility gets mainly involved quadricycles and cars. Between these two vehicle types there are differences in terms of stability, performance, cost, autonomy and safety. The authors studied the implementation of passenger safety devices on a prototype for an electric vehicle derived from a heavy quadricycle. A finite element analysis starting from experimental results was carried out in order to determine the effectiveness in case of frontal and side crashes
Involvement of Norepinephrine in the Control of Activity and Attentive Processes in Animal Models of Attention Deficit Hyperactivity Disorder
Functional and morphological studies in
children affected by Attention Deficit Hyperactivity
Disorder (ADHD) suggest a prefrontal
cortex (PFc) dysfunction. This cortical region is
regulated by subcortical systems including noradrenergic
(NEergic), dopaminergic (DAergic),
cholinergic, serotonergic, and histaminergic pathways.
A wealth of data in humans and in animal
models demonstrates altered dopamine (DA)
regulation. Drugs that modulate norepinephrine
(NE) transmission are also effective in ADHD
patients, thus leading to the hypothesis of a
NEergic disorder. This review covers the
regulation of PFc functions by NE and the
interaction between the NE and DA systems, as
suggested by pharmacological, electrophysiological,
morphological, and gene knock out (KO)
studies. A negative feedback between NE and DA
neurons emerges from KO studies because KO
mice showing increased (NE transporter (NET)
KO) or decreased (DBH and VMAT2 KO) NE
levels are respectively associated with lower and
higher DA levels. Locomotor activity can be
generally predicted by the DA level, whereas
sensitivity to amphetamines is by NE/DA balance.
Some animal models of ADHD, such as
spontaneously hypertensive rats (SHR), show
alterations in the PFc and in the DA system.
Evidence about a correlation between the NE
system and hyper-locomotion activity in such
animals has not yet been clarified. Therefore, this
review also includes recent evidence on the
behavioral effects of two NET blockers,
reboxetine and atomoxetine, in two animal models
of ADHD: SHR and Naples High Excitability rats.
As these drugs modulate the DA level in the PFc,
certain effects are likely to be due to a rebalanced
DA system. We discuss the significance of the
results for theories of ADHD and make
suggestions for future experimentation
CD28 individual signaling up-regulates IL-22 expression and IL-22-mediated effector functions in human T lymphocytes
ILâ22 is a member of the ILâ10 cytokine family involved in host protection against extracellular pathogens, by promoting epithelial cell regeneration and barrier functions. Dysregulation
of ILâ22 production has also frequently been observed in acute respiratory distress syndrome (ARDS) and several chronic inflammatory and autoimmune diseases. We have previously
described that human CD28, a crucial coâstimulatory receptor necessary for full T cell activation, is also able to act as a TCR independent signalling receptor and to induce the
expression of ILâ17A and inflammatory cytokines related to Th17 cells, which together with Th22 cells represent the main cellular source of ILâ22. Here we characterized the role of
CD28 autonomous signalling in regulating ILâ22 expression in human CD4+ T cells. We show that CD28 stimulation in the absence of TCR strongly upâregulates ILâ22 gene expression
and secretion. As recently observed for ILâ17A, we also found that CD28âmediated regulation of ILâ22 transcription requires the cooperative activities of both ILâ6âactivated STAT3 and
RelA/NFâÎș transcription factors. CD28âmediated ILâ22 production also promotes the barrier functions of epithelial cells by inducing mucin and metalloproteases expression. Finally,
by using specific inhibitory drugs, we also identified CD28âassociated class 1A phosphatidylinositol 3âkinase (PI3K) as a pivotal mediator of CD28âmediated ILâ22 expression and ILâ
22âdependent epithelial cell barrier functions
CD28 autonomous signaling orchestrates IL-22 expression and IL-22-regulated epithelial barrier functions in human T lymphocytes
IL-22 is a member of the IL-10 cytokine family involved in host protection against extracellular pathogens, by promoting epithelial cell regeneration and barrier functions. Dysregulation of IL-22 production has also frequently been observed in acute respiratory distress syndrome (ARDS) and several chronic inflammatory and autoimmune diseases. We have previously described that human CD28, a crucial co-stimulatory receptor necessary for full T cell activation, is also able to act as a TCR independent signaling receptor and to induce the expression of IL-17A and inflammatory cytokines related to Th17 cells, which together with Th22 cells represent the main cellular source of IL-22. Here we characterized the role of CD28 autonomous signaling in regulating IL-22 expression in human CD4+ T cells. We show that CD28 stimulation in the absence of TCR strongly up-regulates IL-22 gene expression and secretion. As recently observed for IL-17A, we also found that CD28-mediated regulation of IL-22 transcription requires the cooperative activities of both IL-6-activated STAT3 and RelA/NF-ÎșB transcription factors. CD28-mediated IL-22 production also promotes the barrier functions of epithelial cells by inducing mucin and metalloproteases expression. Finally, by using specific inhibitory drugs, we also identified CD28-associated class 1A phosphatidylinositol 3-kinase (PI3K) as a pivotal mediator of CD28-mediated IL-22 expression and IL-22âdependent epithelial cell barrier functions
Robotic Single-Port da Vinci Surgical System (SP1098) in Gynecologic Surgery: A Systematic Review of Literature
Background: Recently, new surgical systems less invasive than standard laparoscopy have been developed. Among these, robotic single site surgery is playing a pivotal role. In this field, the da Vinci SP (Single-Port) Surgical System (SP1098) is one of the newest surgical technology that presents innovative characteristics that may lead to better surgical outcomes. Few groups have already published their experience and results with this system in gynecology. Methods: The aim of the present systematic review was to provide a comprehensive overview of the status and applications of da Vinci SP1098 in gynecologic surgery. A systematic review of the literature was performed. Studies were identified until September 2022. Results: Six studies were included, reporting a total of 211 patients. The indication for surgery was both benign and malignant disorders. In terms of operative outcomes, the mean/median docking time varied from 2.1 to 5 min while mean/median operating time from 86.5 to 245 min. There was no conversion to multi-port laparoscopy or laparotomy and no major complications related to SP surgery. Conclusions: In conclusion, the preliminary and limited data available regarding the da Vinci SP1098 Surgical System suggest the technical feasibility and safety for its use in gynecologic surgery, with minimal alteration of the surgical technique
Valproic acid and phenobarbital blood levels during the first month of treatment with the ketogenic diet.
Objective â The aim of this study was to assess how the ketogenic diet
influences the blood levels of antiepileptic drugs in the first month of
treatment in a pediatric population with drug-resistant epilepsy. Methods
â The plasma concentrations of antiepileptic drugs were investigated in
an open study on 36 consecutive children and adolescents (20 males),
aged between 6 months and 16 years (mean age 4.7 years), who were
put on the ketogenic diet because of medically refractory epilepsy. The
plasma levels of antiepileptic drugs were determined 30 days and
immediately before the diet and on days 8, 15, 22 and 29 after the start
of the diet. The daily dose of each drug was not changed during the
first month of treatment, while the daily dose of benzodiazepines was
reduced by up to 30% if excessive sedation or drowsiness
occurred. Results â While plasma concentrations of phenobarbital did
not change in the first month on the ketogenic diet (mean increase of
2.3 mg â l 1.0), valproic acid showed a slight but not significant
decrease (mean decresase of 6.7 mg â l 3.2), 2 weeks after the start of
the diet. Conclusions â Adjustments in the daily dose of either drug
before the start of the diet do not however appear to be justified
The combined use of neutrophil gelatinase-associated lipocalin and brain natriuretic peptide improves risk stratification in pediatric cardiac surgery
Abstract
Background: The aim of this study is to test the hypothesis whether the combined use of a cardio-specific biomarker, the brain natriuretic peptide (BNP) and a marker of early renal damage, the assay of urinary neutrophil gelatinase-associated lipocalin (uNGAL), may improve risk stratification in pediatric cardiac surgery.
Methods: We prospectively enrolled 135 children [median age 7 (interquartile range 1â49) months] undergoing to cardiac surgery for congenital heart disease. All biomarkers were evaluated pre- and post-operatively at different times after cardiopulmonary-bypass (CPB): uNGAL at 2, 6 and 12 h; BNP at 12 and 36 h; serum creatinine at 2, 6, 12, and 36 h. Primary endpoints were development of acute kidney injury (AKI) (defined as 1.5 serum creatinine increase) and intubation time.
Results: AKI occurred in 39% of patients (65% neonates and 32% older children, p=0.004). The peak of uNGAL values occurred more frequently at 2 h. uNGAL values at 2 h [median 28.2 (interquartile range 7.0â124.6) ng/L] had a good diagnostic accuracy for early diagnosis of AKI with an AUC (area under the curve) ROC (receiver operating characteristic) curve of 0.85 (SE 0.034). Using multivariable logistic regression analysis, development of AKI was significantly associated with uNGAL values at 2 h after CPB [OR=1.88 (1.30â2.72, p=0.001)], together with the CPB time and Aristotle score, as an index of complexity of the surgical procedure, while pre-operative BNP values were not. Furthermore, uNGAL and pre-operative BNP values (together with Aristotle score) were significantly associated with adverse outcome (longer intubation time and mortality).
Conclusions: Pre-operative BNP and uNGAL values after surgery (together with the Aristotle score) were independently associated with a more severe course and worse outcome in children undergoing cardiac surgery for congenital heart disease.</jats:p
Primary flap closure of perineal defects to avoid empty pelvis syndrome after pelvic exenteration in gynecologic malignancies: An old question to explore a new answer
: Pelvic exenteration (PE) is a radical oncological surgical procedure proposed in patients with recurrent or persistent gynecological cancers. The radical alteration of pelvic anatomy and of pelvic floor integrity can cause major postoperative complications. Fortunately, PE can be combined with reconstructive procedures to decrease complications and functional and support problems of pelvic floor, reducing morbility and mortality and increasing quality of life. Many options for reconstructive surgery have been described, especially a wide spectrum of surgical flaps. Different selection criteria have been proposed to select patients for primary perineal defect flap closure without achieving any strict indication of the best option. The aim of this review is to focus on technical aspects and the advantages and disadvantages of each technique, providing an overview of those most frequently used for the treatment of pelvic floor defects after PE. Flaps based on the deep inferior epigastric artery, especially vertical rectus abdominis musculocutaneous (VRAM) flaps, and gracilis flaps, based on the gracilis muscle, are the most common reconstructive techniques used for pelvic floor and vaginal reconstruction. In our opinion, reconstructive surgery may be considered in case of total PE or type II/III PE and in patients submitted to prior pelvic irradiation. VRAM could be used to close extended defects at the time of PE, while gracilis flaps can be used in case of VRAM complications. Fortunately, numerous choices for reconstructive surgery have been devised. As these techniques continue to evolve, it is advisable to adopt an integrated, multi-disciplinary approach within a tertiary medical center
CTLA-4 and PD-1 Ligand Gene Expression in Epithelial Thyroid Cancers
The dysregulation of PD-1 ligands (PD-L1 and PD-L2) and CTLA-4 ligands (CD80 and CD86) represents a tumor strategy to escape the immune surveillance. Here, the expression of PD-L1, PD-L2, CD80, and CD86 was evaluated at the mRNA level in 94 patients affected by papillary thyroid carcinoma (PTC) and 11 patients affected by anaplastic thyroid carcinoma (ATC). Variations in the mRNAs in PTC patients were then correlated with clinicopathological features. The expression of all genes was deregulated in PTC and ATC tissues compared to normal tissues. In particular, the downregulation of CD80 was observed above all in ATC. In addition, the increased expression of CD80 associated with longer disease-free survival in PTC. Higher expression of PD-L1 associated with the classical histological variant and with the presence of BRAFV600E mutation in PTC. The increased PD-L2 expression correlated with BRAFV600E mutation and lymph node metastasis, while its lower expression correlated with the follicular PTC variant. The latter was also associated with the CD80 downregulation, which was also related to the absence of lymph node metastasis. In conclusion, we documented the overall dysregulation of PD-1 and CTLA-4 ligands in PTC and ATC tissues and a possible prognostic value for CD80 gene expression in PTC
- âŠ