279 research outputs found

    Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy

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    The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectom

    SIGLA - Sistema Integrato per il Monitoraggio e Gestione di Lagune ed Ambiente, sotto-azione CARLA Parte I : CARatterizzazione chimica e chimico-fisica e qualità acque LAguna di Cabras e Golfo di Oristano

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    È stata effettuata una prima caratterizzazione chimica e chimico-fisica della colonna d’acqua nella Laguna di Cabras tramite l’analisi di dati raccolti in precedenti indagini. Tali studi sono stati completati con campionamenti di acqua e misure in situ delle variabili idrologiche nella laguna e nel golfo di Oristano. Su questo set di dati sono state effettuate le analisi per individuare le relazioni tra le variabili misurate e per studiare le variabilità stagionali delle caratteristiche chimico-fisiche della colonna d’acqua. Lo studio ha permesso la compilazione di un protocollo metodologico di indagine e di monitoraggio dello stato trofico e di salute di ambienti lagunari costieri. I dati più recenti hanno mostrato come rispetto alle medie storiche, si sia avuto un aumento della temperatura e una diminuzione della salinità. Quest’ultima viene associata ad un limitato scambio tra la laguna ed il mare. I valori di ossigeno e pH non sono indicativi di un elevato stress ambientale, infatti non sono state rilevate condizioni di ipossia o anossia, e valori di pH superiori alla norma. Tuttavia in precedenti campionamenti nell’estate 2002 sono stati descritti al fondo valori ipossici. Tali valori hanno indicato come la laguna sia periodicamente soggetta a crisi anossiche. Il netto calo di nutrienti rispetto agli anni ottanta-novanta è associato ad una diminuzione degli input d’acqua dolce nel periodo monitorato. Inoltre non è trascurabile l’influenza degli scambi tra sedimento e colonna d’acqua. In conclusione, dagli studi condotti si può dedurre come nello specifico, nella Laguna di Cabras, lo stato trofico del sistema sia principalmente condizionato dagli input d’acqua dolce, e come questi condizionino anche gli scambi con il golfo. In aggiunta, data la diminuzione degli input di acqua dolce nel periodo monitorato e vista la relazione positiva tra volumi e nutrienti in entrata, il loro abbattimento in entrata tramite depurazione delle acque sembra essere un valido strumento di mitigazione e di recupero

    Role of surgical setting and patients-related factors in predicting the occurrence of postoperative pulmonary complications after abdominal surgery

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    OBJECTIVE: The aim of this retrospective study was to evaluate the role of surgical setting (urgent vs. elective) and approach (open vs. laparoscopic) in affecting postoperative pulmonary complications (PPCs) prevalence in patients undergoing abdominal surgery. PATIENTS AND METHODS: After local Ethical Committee approval, 409 patients who had undergone abdominal surgery between January and December 2014 were included in the final analysis. PPCs were defined as the development of one of the following new findings: respiratory failure, pulmonary infection, aspiration pneumonia, pleural effusion, pneumothorax, atelectasis on chest X-ray, bronchospasm or un-planned urgent re-intubation. RESULTS: PPCs prevalence was greater in urgent (33%) vs. elective setting (7%) (chi(2) with Yates correction: 44; p=0.0001) and in open (6%) vs. laparoscopic approach (1.9%) (chi(2) with Yates correction: 12; p=0.0006). PPCs occurrence was positively correlated with in-hospital mortality (Biserial Correlation r=0.37; p=0.0001). Logistic regression showed that urgent setting (p=0.000), Ariscat (Assess Respiratory Risk in Surgical Patients in Catalonia) score (p=0.004), and age (p=0.01) were predictors of PPCs. A cutoff of 23 for Ariscat score was also identified as determining factor for PPCs occurrence with 94% sensitivity and 29% specificity. CONCLUSIONS: Patients undergoing abdominal surgery in an urgent setting were exposed to a higher risk of PPCs compared to patients scheduled for elective procedures. Ariscat score fitted with PPCs prevalence and older patients were exposed to a higher risk of PPCs. Prospective studies are needed to confirm these result

    Impact modelling and a posteriori non-destructive evaluation of homogeneous particleboards of sugarcane bagasse

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    With a view to gaining an in-depth assessment of the response of particleboards (PBs) to different in-service loading conditions, samples of high-density homogeneous PBs of sugarcane bagasse and castor oil polyurethane resin were manufactured and subjected to low velocity impacts using an instrumented drop weight impact tower and four different energy levels, namely 5, 10, 20 and 30 J. The prediction of the damage modes was assessed using Comsol Multiphysics ® . ®. In particular, the random distribution of the fibres and their lengths were reproduced through a robust model. The experimentally obtained dent depths due to the impactor were compared with the ones numerically simulated showing good agreement. The post-impact damage was evaluated by a simultaneous system of image acquisitions coming from two different sensors. In particular, thermograms were recorded during the heating up and cooling down phases, while the specklegrams were gathered one at room temperature (as reference) and the remaining during the cooling down phase. On one hand, the specklegrams were processed via a new software package named Ncorr v.1.2, which is an open-source subset-based 2D digital image correlation (DIC) package that combines modern DIC algorithms proposed in the literature with additional enhancements. On the other hand, the thermographic results linked to a square pulse were compared with those coming from the laser line thermography technique that heats a line-region on the surface of the sample instead of a spot. Surprisingly, both the vibrothermography and the line scanning thermography methods coupled with a robotized system show substantial advantages in the defect detection around the impacted zone

    Optimising calcium phosphate cement formulations to widen clinical applications

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    The demand for reconstructive orthopaedic implants continues expanding at a reasonable pace as the incidence of fracture injuries and infectious diseases rises. There has been an increase in the clinical need for more effective synthetic bone graft materials due to the drawbacks of autogenous grafts. Since the 1980’s calcium phosphate cements (CPC’s) have attracted a great deal of interest due to their chemical similarities to natural bone; chemical, physical and mechanical characteristics have been investigated and manipulated to maximise osteoconductivity and osteointegration of these CPC’s since the start of their commercialisation. Here in this thesis, a series of investigation are complied to demonstrate novel and inventive approaches to expand the application of CPC’s: (1) limiting the liquid phase in the setting reaction of a brushite cement to produce monetite (dehydrated brushite) based cement, with increased solubility to overcome the problems faced by long term stability of hydroxyapatite (HA) cements; (2) manipulating the cement formulation to produce a cement that can set on a change in temperature, upon implantation, increasing handling time during surgeries; (3) incorporating therapeutic molecules to eliminate secondary surgeries following infectious diseases; (4) to enhance osteointegration of CPC’s by synchronising the degradation to natural bone formation. Results exhibit compressive strength appropriate for the application of cranioplasty; long term ageing studies demonstrates that the novel cement formulations do not hydrolyse to HA, eliminating the risk of catastrophic brittle failure that is commonly associated with CPC’s.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    Subregional DXA-derived vertebral bone mineral measures are stronger predictors of failure load in specimens with lower areal bone mineral density, compared to those with higher areal bone mineral density

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    Measurement of areal bone mineral density (aBMD) in intravertebral subregions may increase the diagnostic sensitivity of dual-energy X-ray absorptiometry (DXA)-derived parameters for vertebral fragility. This study investigated whether DXA-derived bone parameters in vertebral subregions were better predictors of vertebral bone strength in specimens with low aBMD, compared to those with higher aBMD. Twenty-five lumbar vertebrae (15 embalmed and 10 fresh-frozen) were scanned with posteroanterior- (PA) and lateral-projection DXA, and then mechanically tested in compression to ultimate failure. Whole-vertebral aBMD and bone mineral content (BMC) were measured from the PA- and lateral-projection scans and within 6 intravertebral subregions. Multivariate regression was used to predict ultimate failure load by BMC, adjusted for vertebral size and specimen fixation status across the whole specimen set, and when subgrouped into specimens with low aBMD and high aBMD. Adjusted BMC explained a substantial proportion of variance in ultimate vertebral load, when measured over the whole vertebral area in lateral projection (adjusted R2 0.84) and across the six subregions (ROIs 2–7) (adjusted R2 range 0.58–0.78). The association between adjusted BMC, either measured subregionally or across the whole vertebral area, and vertebral failure load, was increased for the subgroup of specimens with identified ‘low aBMD’, compared to those with ‘high aBMD’, particularly in the anterior subregion where the adjusted R2 differed by 0.44. The relative contribution of BMC measured in vertebral subregions to ultimate failure load is greater among specimens with lower aBMD, compared to those with higher aBMD, particularly in the anterior subregion of the vertebral body

    Characterization and genome sequencing of a Citrobacter freundii phage CfP1 harboring a lysin active against multidrug-resistant isolates

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    Citrobacter spp., although frequently ignored, is emerging as an important nosocomial bacterium able to cause various superficial and systemic life-threatening infections. Considered to be hard-to-treat bacterium due to its pattern of high antibiotic resistance, it is important to develop effective measures for early and efficient therapy. In this study, the first myovirus (vB_CfrM_CfP1) lytic for Citrobacter freundii was microbiologically and genomically characterized. Its morphology, activity spectrum, burst size, and biophysical stability spectrum were determined. CfP1 specifically infects C. freundii, has broad host range (>85 %; 21 strains tested), a burst size of 45 PFU/cell, and is very stable under different temperatures (20 to 50 °C) and pH (3 to 11) values. CfP1 demonstrated to be highly virulent against multidrug-resistant clinical isolates up to 12 antibiotics, including penicillins, cephalosporins, carbapenems, and fluroquinoles. Genomically, CfP1 has a dsDNA molecule with 180,219 bp with average GC content of 43.1 % and codes for 273 CDSs. The genome architecture is organized into function-specific gene clusters typical for tailed phages, sharing 46 to 94 % nucleotide identity to other Citrobacter phages. The lysin gene encoding a predicted D-Ala-D-Ala carboxypeptidase was also cloned and expressed in Escherichia coli and its activity evaluated in terms of pH, ionic strength, and temperature. The lysine optimum activity was reached at 20 mM HEPES, pH 7 at 37 °C, and was able to significantly reduce all C. freundii (>2 logs) as well as Citrobacter koseri (>4 logs) strains tested. Interestingly, the antimicrobial activity of this enzyme was performed without the need of pretreatment with outer membrane-destabilizing agents. These results indicate that CfP1 lysin is a good candidate to control problematic Citrobacter infections, for which current antibiotics are no longer effective.This study was funded by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER006684), and the PhD grants SFRH/BPD/111653/2015 and SFRH/BPD/69356/2010
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