10 research outputs found

    RFID over Low Cost VCSEL-based MMF Links: Experimental Demonstration and Distortion Study

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    Radio-over-Fibre (RoF) Distributed Antenna System (DAS) technology has been investigated for the distribution of ultra-high frequency (UHF) radio frequency identification (RFID) signals. RoF DAS allows for reduced number of readers and centralized placement of readers which facilitates easy system maintenance, but it is important to find a low-cost solution that can achieve comparable performance to a conventional RFID system. In this work, a lowcost vertical cavity surface-emitting laser (VCSEL)-based multimode fibre (MMF) link has been developed and demonstrated for passive UHF RFID applications. The reported results show almost the same performance when compared with a conventional RFID system. In addition, simple spatial antenna diversity schemes are tested, with improved performance reported in comparison with a RFID-RoF system without diversity. Also, an investigation of RFID over fibre with RoF nonlinearity is carried out showing that PR-ASK RFID modulation allows for higher levels of RF carrier and modulated signal power than the ASK RFID, for low levels of nonlinearity

    In vitro activity of dalbavancin and other anti-staphylococcal agents against infecting isolates of methicillin-resistant coagulase-negative staphylococci.

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    Introduction. Dalbavancin was approved in Europe in 2015 for skin and soft tissue infections.Hypothesis/Gap Statement. Data on methicillin-resistant coagulase-negative staphylococci (MR-CNS) dalbavancin susceptibility are scarce.Aim. To assess the susceptibility of MR-CNS to dalbavancin and other anti-staphylococcal agents.Methodology. A total of 443 MR-CNS clinical isolates from patients hospitalized in a Greek university hospital during a 2.5-year period (January 2018 to June 2020) were included. The MICs for vancomycin, teicoplanin, linezolid and daptomycin were investigated by Etest and the MIC for dalbavancin was determined according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines in 196 isolates. The consumption of the aforementioned antimicrobials was calculated.Results. In total, 51 isolates were resistant to teicoplanin (11.5 %) and 211 (47.6 %) to linezolid; all were susceptible to vancomycin and daptomycin. Among 196 isolates tested, 32 (16.3 %) were resistant to dalbavancin. A significant increase of MIC during the study period was found for vancomycin, teicoplanin and daptomycin, while a decrease in linezolid's MIC was observed. Dalbavancin's MIC remained stable. No difference in consumption was observed among the studied anti-staphylococcal agents.Conclusion. An increase of vancomycin, teicoplanin and daptomycin MICs among MR-CNS was observed, whereas 47.6 % of isolates were non-susceptible to linezolid. Dalbavancin retains excellent potency against MR-CNS, even in the presence of non-susceptibility to other anti-staphylococcal antibiotics

    A Seven-Year Microbiological and Molecular Study of Bacteremias Due to Carbapenemase-Producing Klebsiella Pneumoniae: An Interrupted Time-Series Analysis of Changes in the Carbapenemase Gene's Distribution after Introduction of Ceftazidime/Avibactam.

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    Ceftazidime/avibactam (CZA) is a new option for the treatment of KPC-producing Klebsiella pneumoniae. The aim of this study was to determine resistance patterns and carbapenemase genes among K. pneumoniae (CP-Kp) bacteremic isolates before and after CZA introduction. K. pneumoniae from blood cultures of patients being treated in a Greek university hospital during 2015-21 were included. PCR for bla <sub>KPC</sub> , bla <sub>VIM</sub> , bla <sub>NDM</sub> and bla <sub>OXA-48</sub> genes was performed. Among 912 K. pneumoniae bacteremias: 725 (79.5%) were due to carbapenemase-producing isolates; 488 (67.3%) carried bla <sub>KPC</sub> ; 108 (14.9%) bla <sub>VIM</sub> ; 100 (13.8%) bla <sub>NDM</sub> ; and 29 (4%) carried a combination of bla <sub>KPC</sub> , bla <sub>VIM</sub> or bla <sub>NDM</sub> . The incidence of CP-Kp bacteremias was 59 per 100,000 patient-days. The incidence of CP-Kp changed from a downward pre-CZA trend to an upward trend in the CZA period (p = 0.007). BSIs due to KPC-producing isolates showed a continuous downward trend in the pre-CZA and CZA periods (p = 0.067), while BSIs due to isolates carrying bla <sub>VIM</sub> or bla <sub>NDM</sub> changed from a downward trend in the pre-CZA to an upward trend in the CZA period (p < 0.001). An abrupt change in the epidemiology of CP-Kp was observed in 2018, due to the re-emergence of VIM-producing isolates after the suppression of KPC-producing ones via the use of CZA

    Risk factors for acute kidney injury in critically ill patients with bacteraemia by carbapenem non-susceptible Gram negative bacteria.

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    The objectives of the present study were to identify risk factors for development of acute kidney injury (AKI) during the treatment of bacteraemia due to carbapenem non-susceptible Gram-negative bacteria (CnS-GNB) and its role on mortality. Data of all patients with bacteraemia by CnS-GNB in the intensive care unit of a tertiary hospital from 2012 to 2016 were included. AKI was defined by AKIN criteria. Secondary outcomes were AKI development in patients treated with colistin and predictors of 14-day mortality. Among 285 episodes of bacteraemia due to CnS-GNB, 84 (29.5%) developed AKI. Multivariate analysis revealed that obesity, septic shock, maximum noradrenaline dose and eGFR<60 mL/min/1.73m² upon bacteraemia onset were independently associated with development of AKI. Out of 228 patients receiving colistin, 64 (28.1%) developed AKI. Multivariate analysis found the same factors as before in addition to voriconazole administration. Fourteen-day mortality was 34.2% and was independently associated with bacteraemia by Pseudomonas aeruginosa, AKI during bacteraemia treatment, maximum noradrenaline dose, SAPS II and SOFA scores upon bacteraemia onset, whereas appropriate combination therapy and catheter-related bacteraemia were independently associated with better survival. AKI was a frequent complication of bacteraemia by CnS-GNB and was associated with septic shock and baseline renal function impairment. Mortality was higher among patients that developed AKI due to bacteraemia. Colistin should be considered a safe therapeutic option for treating such infections

    Vitamin D-related immunomodulation in patients with liver cirrhosis

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    Objective(s) Increasing evidence indicates that Vitamin D status is linked to severity of liver cirrhosis and patients' survival. However, the potential role of Vitamin D-related immunomodulation in hepatic decompensation and patients' mortality in relation to Vitamin D deficiency remains unknown. The aim of the current study is to evaluate the association between Vitamin D status and Vitamin D binding protein (VDBP) levels with serum cytokine and lipopolysaccharide binding protein (LBP) and to examine their role on disease severity and cirrhotics' mortality. Methods One hundred consecutive Caucasian patients with liver cirrhosis were enrolled in the study. 25(OH)D, VDBP, and LBP concentrations were assessed by ELISA. Cytokine tumor necrosis factor-a (TNF-a), interleukin 6 (IL-6), IL-1ß, IL-8, IL-10, and IL-12 levels were determined by Cytometric Bead Array. Results 25(OH)D levels were inversely correlated with CP score, MELD, IL-6, and CP stage and VDBP levels with CP score, MELD, IL-6, IL-8, LBP, and CP stage. Cirrhotics with 25(OH)D deficiency and severe deficiency had significantly higher CP score, increased IL-6 levels and lower VDBP levels. In the multivariate analysis, the independent prognostic factors associated with patients' survival were CP stage B [hazard ratio = 6.75; 95% confidence interval (CI) 1.32, 34.43; P = 0.022], CP stage C (hazard ratio = 7.39; 95% CI 1.41, 38.81; P = 0.018), the presence of hepatocellular carcinoma (hazard ratio = 4.50; 95% CI 1.54, 13.13; P = 0.006) and 25(OH)D levels (hazard ratio = 0.87; 95% CI 0.80, 0.95; P = 0.002). Conclusion The results show that Vitamin D status and VDBP levels are associated with liver cirrhosis severity and patients' mortality, possibly through a proinflammatory immune response. © 2020 Lippincott Williams and Wilkins. All rights reserved

    Natural history of grade 1 ascites in patients with liver cirrhosis

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    Background No evidence is available on the natural history of grade 1 ascites and its progression to grade 2/3 in patients with liver cirrhosis. The aim of the current study was to address this issue, to assess the development of main comorbid disorders closely related to ascites progression, and to identify the predictive factors for survival in this setting. Methods Consecutive Caucasian cirrhotic patients with grade 1 ascites were retrospectively analyzed. None of patients was under treatment with diuretics at diagnosis. Control groups consisted of 145 cirrhotics with grade 2/3 ascites and 175 cirrhotics without ascites. Results Diuretics were initiated in 58 patients with grade 1 ascites at baseline by the attending physician. At the last follow up, 29 patients had no ascites, 33 patients had grade 1 and 38 patients had grade 2/3 ascites. No variable was found to be an independent predictor of grade 2/3 ascites. Seven patients developed spontaneous bacterial peritonitis while under treatment with diuretics; at that time only 1 patient had grade 1 ascites. The mortality rate was similar among all examined groups. Conclusions This study suggests that the presence of grade 1 ascites does not constitute a precursor of grade 2/3 ascites in patients with cirrhosis. Thus, patients with grade 1 ascites do not require specific treatment with diuretics. © 2021 Hellenic Society of Gastroenterology

    Protective effects of Salvia miltiorrhizae on the hearts of rats with severe acute pancreatits or obstructive jaundice*

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    Objective: To investigate the therapeutic effects and mechanisms of Salvia miltiorrhizae (Danshen) in the treatment of severe acute pancreatitis (SAP)- or obstructive jaundice (OJ)-induced heart injury. Methods: A total of 288 rats were used for SAP- (n=108) and OJ-associated (n=180) experiments. The rats were randomly divided into sham-operated, model control, and Salvia miltiorrhizae-treated groups. According to the difference of time points after operation, SAP rats in each group were subdivided into 3, 6 and 12 h subgroups (n=12), whereas OJ rats were subdivided into 7, 14, 21, and 28 d subgroups (n=15). At the corresponding time points after operation, the mortality rates of the rats, the contents of endotoxin and phospholipase A2 (PLA2) in blood, and pathological changes of the hearts were investigated. Results: The numbers of dead SAP and OJ rats in the treated groups declined as compared with those in the model control group, but not significantly (P>0.05). The contents of endotoxin (at 6 and 12 h in SAP rats and on 7, 14, 21, and 28 d in OJ rats, respectively) and PLA2 (at 6 and 12 h in SAP rats and on 28 d in OJ rats, respectively) in the treated group were significantly lower than those in the model control group (P<0.01 and P<0.001, respectively). Besides, myocardial pathological injuries were mitigated in SAP and OJ rats. Conclusion: In this study, we found that Salvia miltiorrhizae improved myocardial pathological changes, reduced the content of PLA2 in blood, and decreased the mortality rates of SAP and OJ rats, exerting protective effects on the hearts of the rats

    Dynamic Localization of Hepatocellular Transporters: Role in Biliary Excretion and Impairment in Cholestasis

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