201 research outputs found
Simple large wood structures promote hydromorphological heterogeneity and benthic macroinvertebrate diversity in low-gradient rivers
This work has been carried out within the SMART Joint Doctorate Programme ‘Science for the MAnagement of Rivers and their Tidal systems’ funded by the Erasmus Mundus programme of the European Union
Rotating biological contactors : a review on main factors affecting performance
Rotating biological contactors (RBCs)
constitute a very unique and superior alternative
for biodegradable matter and nitrogen removal on
account of their feasibility, simplicity of design and
operation, short start-up, low land area requirement,
low energy consumption, low operating and maintenance
cost and treatment efficiency. The present
review of RBCs focus on parameters that affect
performance like rotational speed, organic and
hydraulic loading rates, retention time, biofilm support
media, staging, temperature, influent wastewater
characteristics, biofilm characteristics, dissolved oxygen
levels, effluent and solids recirculation, stepfeeding
and medium submergence. Some RBCs
scale-up and design considerations, operational problems
and comparison with other wastewater treatment
systems are also reported.Fundação para a Ciência e a Tecnologia (FCT
International research and guidelines on post-tuberculosis chronic lung disorders: a systematic scoping review.
Introduction: Pulmonary tuberculosis (TB) is an important risk factor for chronic respiratory disease due to residual lung damage. Yet, the WHO End TB strategy does not mention post-TB chronic lung disorders (PTBLDs) and programmatic interventions to address PTBLD are lacking. This study assessed the scope of current guidelines and evidence on PTBLD to inform policy and research action. Methods: A systematic literature search was conducted following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Eight databases (TRIP, International Guideline Library, MEDLINE/PubMed, EMBASE, Web of Science, Global Health, Cochrane Library) were searched for records on PTBLD published between 1 January 1990 and 1 December 2017. Non-English records, case series, conference abstracts and letters to editors were excluded. Data were extracted and charted on publication year, location, PTBLD condition(s) and main study outcome. Results: A total of 212 guidelines and 3661 articles were retrieved. After screening, only three international TB guidelines mentioned TB sequelae, but none described how to identify or manage the condition. A total of 156 articles addressed PTBLD: 54 (35%) mentioned unspecified TB sequelae; 47 (30%) specific post-TB conditions including aspergillosis, bronchial stenosis or bronchiectasis; 52 (33%) post-TB obstructive disorders or lung function impairment; and 20 (13%) post-TB respiratory symptoms or chest X-ray abnormalities. The first two groups mostly assessed surgery or ventilation techniques for patient management, while the last two groups typically assessed prevalence or predictors of disease. Conclusion: This is the first review to provide a comprehensive overview of the current literature on PTBLD. The scope of evidence around the burden of PTBLD warrants inclusion and recognition of the problem in international TB guidelines. Research is now needed on early detection of PTBLD and patient management options that are suitable for high-burden TB countries
International research and guidelines on post-tuberculosis chronic lung disorders: a systematic scoping review.
Introduction: Pulmonary tuberculosis (TB) is an important risk factor for chronic respiratory disease due to residual lung damage. Yet, the WHO End TB strategy does not mention post-TB chronic lung disorders (PTBLDs) and programmatic interventions to address PTBLD are lacking. This study assessed the scope of current guidelines and evidence on PTBLD to inform policy and research action. Methods: A systematic literature search was conducted following Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Eight databases (TRIP, International Guideline Library, MEDLINE/PubMed, EMBASE, Web of Science, Global Health, Cochrane Library) were searched for records on PTBLD published between 1 January 1990 and 1 December 2017. Non-English records, case series, conference abstracts and letters to editors were excluded. Data were extracted and charted on publication year, location, PTBLD condition(s) and main study outcome. Results: A total of 212 guidelines and 3661 articles were retrieved. After screening, only three international TB guidelines mentioned TB sequelae, but none described how to identify or manage the condition. A total of 156 articles addressed PTBLD: 54 (35%) mentioned unspecified TB sequelae; 47 (30%) specific post-TB conditions including aspergillosis, bronchial stenosis or bronchiectasis; 52 (33%) post-TB obstructive disorders or lung function impairment; and 20 (13%) post-TB respiratory symptoms or chest X-ray abnormalities. The first two groups mostly assessed surgery or ventilation techniques for patient management, while the last two groups typically assessed prevalence or predictors of disease. Conclusion: This is the first review to provide a comprehensive overview of the current literature on PTBLD. The scope of evidence around the burden of PTBLD warrants inclusion and recognition of the problem in international TB guidelines. Research is now needed on early detection of PTBLD and patient management options that are suitable for high-burden TB countries
A modeling and simulation study of siderophore mediated antagonism in dual-species biofilms
<p>Abstract</p> <p>Background</p> <p>Several bacterial species possess chelation mechanisms that allow them to scavenge iron from the environment under conditions of limitation. To this end they produce siderophores that bind the iron and make it available to the cells later on, while rendering it unavailable to other organisms. The phenomenon of siderophore mediated antagonism has been studied to some extent for suspended populations where it was found that the chelation ability provides a growth advantage over species that do not have this possibility. However, most bacteria live in biofilm communities. In particular <it>Pseudomonas fluorescens </it>and <it>Pseudomonas putida</it>, the species that have been used in most experimental studies of the phenomenon, are known to be prolific biofilm formers, but only very few experimental studies of iron chelation have been published to date for the biofilm setting. We address this question in the present study.</p> <p>Methods</p> <p>Based on a previously introduced model of iron chelation and an existing model of biofilm growth we formulate a model for iron chelation and competition in dual species biofilms. This leads to a highly nonlinear system of partial differential equations which is studied in computer simulation experiments.</p> <p>Conclusions</p> <p>(i) Siderophore production can give a growth advantage also in the biofilm setting, (ii) diffusion facilitates and emphasizes this growth advantage, (iii) the magnitude of the growth advantage can also depend on the initial inoculation of the substratum, (iv) a new mass transfer boundary condition was derived that allows to a priori control the expect the expected average thickness of the biofilm in terms of the model parameters.</p
Predicting Transitions in Low and High Levels of Risk Behavior from Early to Middle Adolescence: The TRAILS Study
The present study examined the joint development of substance use and externalizing problems in early and middle adolescence. First, it was tested whether the relevant groups found in previous studies i.e., those with an early onset, a late onset, and no onset or low levels of risk behavior could be identified, while using a developmental model of a single, underlying construct of risk behavior. Second, departing from Moffitt’s taxonomy of antisocial behavior, it was tested if early, but not late, onset risk behavior is predicted by a problematic risk profile in childhood. Data were used from TRAILS, a population based cohort study, starting at age 11 with two follow-ups at mean ages of 13.6 and 16.3 years. Latent transition analyses demonstrated that, both in early and middle adolescence, a single underlying construct of risk behavior, consisting of two classes (labeled as low and high risk behavior), adequately represented the data. Respondents could be clearly classified into four possible transition patterns from early to middle adolescence, with a transition from high to low being almost non-existent (2.5 %), low to low (39.4 %) and low to high (41.8 %) being the most prevalent, and high to high (16.2 %) substantial. As hypothesized, only the high-high group was characterized by a clear adverse predictor profile in late childhood, while the low-high group was not. This study demonstrates that the development of substance use is correlated with externalizing problems and underscores the theory that etiologies of early and later onset risk behavior are different
Regulation of DNA Repair Mechanism in Human Glioma Xenograft Cells both In Vitro and In Vivo in Nude Mice
Glioblastoma Multiforme (GBM) is the most lethal form of brain tumor. Efficient DNA repair and anti-apoptotic mechanisms are making glioma treatment difficult. Proteases such as MMP9, cathepsin B and urokinase plasminogen activator receptor (uPAR) are over expressed in gliomas and contribute to enhanced cancer cell proliferation. Non-homologous end joining (NHEJ) repair mechanism plays a major role in double strand break (DSB) repair in mammalian cells.Here we show that silencing MMP9 in combination with uPAR/cathepsin B effects NHEJ repair machinery. Expression of DNA PKcs and Ku70/80 at both mRNA and protein levels in MMP9-uPAR (pMU) and MMP9-cathepsin B (pMC) shRNA-treated glioma xenograft cells were reduced. FACS analysis showed an increase in apoptotic peak and proliferation assays revealed a significant reduction in the cell population in pMU- and pMC-treated cells compared to untreated cells. We hypothesized that reduced NHEJ repair led to DSBs accumulation in pMU- and pMC-treated cells, thereby initiating cell death. This hypothesis was confirmed by reduced Ku70/Ku80 protein binding to DSB, increased comet tail length and elevated γH2AX expression in treated cells compared to control. Immunoprecipitation analysis showed that EGFR-mediated lowered DNA PK activity in treated cells compared to controls. Treatment with pMU and pMC shRNA reduced the expression of DNA PKcs and ATM, and elevated γH2AX levels in xenograft implanted nude mice. Glioma cells exposed to hypoxia and irradiation showed DSB accumulation and apoptosis after pMU and pMC treatments compared to respective controls.Our results suggest that pMU and pMC shRNA reduce glioma proliferation by DSB accumulation and increase apoptosis under normoxia, hypoxia and in combination with irradiation. Considering the radio- and chemo-resistant cancers favored by hypoxia, our study provides important therapeutic potential of MMP9, uPAR and cathepsin B shRNA in the treatment of glioma from clinical stand point
Negative pressure wound therapy: Potential publication bias caused by lack of access to unpublished study results data
<p>Abstract</p> <p>Background</p> <p>Negative pressure wound therapy (NPWT) is widely applied, although the evidence base is weak. Previous reviews on medical interventions have shown that conclusions based on published data alone may no longer hold after consideration of unpublished data. The main objective of this study was to identify unpublished randomised controlled trials (RCTs) on NPWT within the framework of a systematic review.</p> <p>Methods</p> <p>RCTs comparing NPWT with conventional wound therapy were identified using MEDLINE, EMBASE, CINAHL and The Cochrane Library. Every database was searched from inception to May 2005. The search was updated in December 2006. Reference lists of original articles and systematic reviews, as well as congress proceedings and online trial registers, were screened for clues to unpublished RCTs. Manufacturers of NPWT devices and authors of conference abstracts were contacted and asked to provide study information. Trials were considered nonrandomised if concealment of allocation to treatment groups was classified as "inadequate". The study status was classified as "completed", "discontinued", "ongoing" or "unclear". The publication status of completed or discontinued RCTs was classified as "published" if a full-text paper on final study results (completed trials) or interim results (discontinued trials) was available, and "unpublished" if this was not the case. The type of sponsorship was also noted for all trials.</p> <p>Results</p> <p>A total of 28 RCTs referring to at least 2755 planned or analysed patients met the inclusion criteria: 13 RCTs had been completed, 6 had been discontinued, 6 were ongoing, and the status of 3 RCTs was unclear. Full-text papers were available on 30% of patients in the 19 completed or discontinued RCTs (495 analysed patients in 10 published RCTs vs. 1154 planned patients in 9 unpublished RCTs). Most information about conference abstracts and unpublished study information referring to trials that were unpublished at the time these documents were generated was obtained from the manufacturer Kinetic Concepts Inc. (KCI) (19 RCTs), followed by The Cochrane Library (18) and a systematic review (15). We were able to obtain some information on the methods of unpublished RCTs, but results data were either not available or requests for results data were not answered; the results of unpublished RCTs could therefore not be considered in the review. One manufacturer, KCI, sponsored the majority of RCTs (19/28; 68%). The sponsorship of the remaining trials was unclear.</p> <p>Conclusion</p> <p>Multi-source comprehensive searches identify unpublished RCTs. However, lack of access to unpublished study results data raises doubts about the completeness of the evidence base on NPWT.</p
Management of Hypertension in Chronic Kidney Disease
Chronic kidney disease (CKD) is an increasingly prevalent condition globally and is strongly associated with incident cardiovascular disease (CVD). Hypertension is both a cause and effect of CKD and affects the vast majority of CKD patients. Control of hypertension is important in those with CKD as it leads to slowing of disease progression as well as reduced CVD risk. Existing guidelines do not offer a consensus on optimal blood pressure (BP) targets. Therefore, an understanding of the evidence used to create these guidelines is vital when considering how best to manage individual patients. Non-pharmacological interventions are useful in reducing BP in CKD but are rarely sufficient to control BP adequately. Patients with CKD and hypertension will often require a combination of antihypertensive medications to achieve target BP. Certain pharmacological therapies provide additional BP-independent renoprotective and/or cardioprotective action and this must be considered when instituting therapy. Managing hypertension in the context of haemodialysis and following kidney transplantation presents further challenges. Novel therapies may enhance treatment in the near future. Importantly, a personalised and evidence-based management plan remains key to achieving BP targets, reducing CVD risk and slowing progression of CKD.</p
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