51 research outputs found

    Impact of topology on layer 2 switched QoS sensitive services

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    High-bandwidth QoS sensitive services such as large scale video surveillance generally depend on provisioned capacity delivered by circuit-switched technology such as SONET/SDH. Yet development in layer 2 protocol sets and manageability extensions to Ethernet standards propose layer 2 packet switching technology as a viable, cheaper alternative to SONET/SDH. Layer 2 switched networks traditionally offer more complex topologies; in this paper we explain general QoS issues with layer 2 switching and show the impact of topology choice on service performance

    General anesthesia for surgical treatment of urethral obstruction in nine goats

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    Nine pygmy goats underwent surgical treatment for obstructive urolithiasis in a period of six months. In two cases, (second) revision surgery was necessary resulting in a total of twelve procedures under general anesthesia. Different anesthetic protocols were applied: analgesia was provided by an opioid (12/12) combined with either benzodiazepine (10/12) or an alpha-2 agonist (2/12). Anesthesia was induced with propofol (10/12) or ketamine (2/12) and maintained with isofiurane (8/12) or SeVallralle (4/12) in oxygen in a semi-closed circle system with continuous monitoring during anesthesia. Minor complications were mild bradycardia (4/12), hypotension (3/12), metabolic acidosis (1/12) and hypothermia (12/12). In four cases, epidural anesthesia was performed; in one of those four cases, severe complications developed (paralysis, 1/4). The goat was euthanized later. Although urethral obstruction increases the risk of general anesthesia, the selection of an appropriate anesthetic protocol, adequate preoperative examination/ preparation and detailed monitoring throughout anesthesia reduced the incidence of severe complications in this case series

    HIV prevention through sport: the case of the Mathare Youth Sport Association in Kenya.

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    Sport has become a popular tool for HIV prevention, based on claims that it can foster life skills that are necessary to translate knowledge, attitudes and behavioural intentions into actual behaviour. Empirical evidence of the effectiveness of sport-based HIV prevention programmes is, however, sorely lacking. We therefore conducted a cross-sectional survey assessing sexual behaviour and the determinants thereof among 454 youth of the Mathare Youth Sport Association (MYSA) in Kenya and a control group of 318 non-MYSA members. Multiple (ordinal) logistic regression models were applied to measure the association between MYSA membership and attitudes, subjective norms and self-efficacy related to condom use as well as sexual experience, age at sexual debut, condom use, history of concurrent relationships and number of partners in the last year. MYSA members were more likely to use condoms during the first sex act (odds ratio (OR)=2.10; 95% CI: 1.10–3.99). Consistent condom use with the current/last partner was 23.2% (36/155) among MYSA members vs. 17.2% (17/99) among the control group. Even after adjusting for media exposure – a factor associated with both MYSA membership and higher frequency of condom use – MYSA members were still found to use condoms more frequently with their current/last partner (adjusted OR=1.64; 95% CI: 1.01–2.68). Nevertheless, levels of condom use remain disturbingly low. More rigorous evaluations of sport programmes for HIV prevention are needed. When possible, programmes should be preceded by baseline assessments, trends in risk behaviour of the intervention group should be compared with those of a control group, and protocols for data collection and analysis should include measuring of and adjusting for potentially confounding factors

    Complement component C3 and C5b-9 deposition on hypoxia reperfused endothelial cells by non-HLA antibodies against RhoGDI2: A player involved in graft failure?

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    Antibodies against Rho GDP-dissociation inhibitor 2 (RhoGDI2) are associated with inferior graft survival in transplant patients receiving a kidney from deceased donors. Although this suggests that these antibodies contribute to graft injury because of ischemia, it remains unknown whether they are also pathogenically involved in the process of graft loss. To study this, we firstly analyzed the IgG subclass profile of anti-RhoGDI2 antibodies in kidney transplant recipients, and whether antibody titers change over time or because of acute rejection. Next, we investigated the expression of RhoGDI2 on primary kidney and lung endothelial cells (ECs) upon hypoxia reperfusion. In addition, the complement-fixing properties of anti-RhoGDI2 antibodies were studied using imaging flow cytometry. Anti-RhoGDI2 antibodies in patients are mainly IgG1, and titers remained stable and seemed not be changed because of rejection. Antibodies against RhoGDI2, which surface expression seemed to increase upon hypoxia reperfusion, co-localized with C3 on ECs. Binding of human IgG1 monoclonal anti-RhoGDI2 antibodies as well as patient derived antibodies, resulted in complement activation, suggesting that these antibodies are complement fixing. This study suggested a potential pathogenic role of anti-RhoGDI2 antibodies in kidney graft loss. During ischemia reperfusion, the ability of these antibodies to fix complement could be one of the mechanisms resulting in tissue injury

    Sorted B cell transcriptomes point towards actively regulated B cell responses during ongoing chronic hepatitis B infections

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    The natural course of chronic hepatitis B virus (HBV) infections follows distinct clinical disease phases, char-acterized by fluctuating levels of serum HBV DNA and ALT. The immune cells and their features that govern these clinical disease transitions remain unknown. In the current study, we performed RNA sequencing on pu-rified B cells from blood (n = 42) and liver (n = 10) of healthy controls and chronic HBV patients. We found distinct gene expression profiles between healthy controls and chronic HBV patients, as evidenced by 190 differentially expressed genes (DEG), but also between the clinical phenotypes of a chronic HBV infection (17?110 DEG between each phase). Numerous immune pathways, including the B cell receptor pathway were upregulated in liver B cells when compared to peripheral B cells. Further investigation of the detected DEG suggested an activation of B cells during HBeAg seroconversion and an active regulation of B cell signalling in the liver

    Exploring the 3D printing of molybdenum carbide-based catalysts for the reverse water gas shift reaction: A multi scale study

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    A new methodology for preparing 3D printing molybdenum carbide-based catalysts with direct ink writing is presented. CO2 conversion experiments through the reverse water gas shift reaction showed that the catalytic behavior of 3D-MoxC/Al2O3 catalysts is controlled by the crystallite size and crystalline phase, which in turn were dependent on the Mo loading. The formation of cubic δ-MoC and hexagonal η-Mo3C2 was prevalent in small crystallite sizes at low loading of Mo, and α/β-Mo2C in larger crystallite sizes at high loading of Mo. Operando DRIFTS experiments points out that hydroxyl species present on the surface of Al2O3 play a major role in bicarbonate formation that leads to the formation of formates, which eventually decomposes to CO and H2O. The produced structures were mechanically stable and kept their structural and textural properties after reaction. Therefore, this work introduces new perspectives for scaling-up 3D printed structures based on molybdenum carbide

    Retreatment of hepatitis C non-responsive to Interferon. A placebo controlled randomized trial of Ribavirin monotherapy versus combination therapy with Ribavirin and Interferon in 121 patients in the Benelux [ISRCTN53821378]

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    BACKGROUND: Evidence based medicine depends on unbiased selection of completed randomized controlled trials. For completeness it is important to publish all trials. This report describes the first large randomised controlled trial where combination therapy was compared to placebo therapy and to ribavirin monotherapy, which has not been published untill now. METHODS: One hundred and twenty one patients with chronic hepatitis C and elevated transaminases who did not respond to previous treatment with standard interferon monotherapy, were included from 16 centers in Belgium, the Netherlands and Luxembourg between 1992 and 1996. Patient poor-response characteristics were: genotype 1 (69%), HCV RNA above 2 × 10(6 )copies/ml (55%) and cirrhosis (38%). Patients were randomized to 6 months combination therapy with interferon alpha-2b (3 MU tiw) and ribavirin (1000–1200 mg / day), 6 months ribavirin monotherapy (1000–1200 mg / day) or 6 months ribavirin placebo. The study was double blinded for the ribavirin / placebo component. One patient did not fit the entry criteria, and 3 did not start. All 117 patients who received at least one dose of treatment were included in the intention to treat analysis. RESULTS: At the end of treatment, HCV RNA was undetectable in 35% of patients on combination therapy and in none of the patients treated with ribavirin monotherapy or placebo. The sustained virological response rate at 6 months after therapy was 15% for patients treated with interferon and ribavirin. During the 6 months treatment period 13% of patients on interferon ribavirin combination therapy, 13% of patients on ribavirin monotherapy and 11% of patients on placebo withdrew due to side effects or noncompliance. At 24 weeks of treatment the mean Hb level was 85% of the baseline value, which means a mean decrease from 9.1 mmol/l to 7.8 mmol/l. The Hb levels at the end of treatment were not significantly different from patients treated with ribavirin monotherapy (p = 0.76). End of treatment WBC was significantly lower in patients treated with combination therapy, compared to ribavirin (p < 0.01) as well as for patients treated with ribavirin monotherapy compared to placebo (p < 0.01). DISCUSSION: This belated report on the only placebo controlled study of interferon ribavirin combination therapy in non responders to standard doses of interferon monotherapy documents the effectiveness, be it limited, of this approach as well as the dynamics of the effects on blood counts
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