Variable sediment oxygen uptake in response to dynamic forcing

Seiche-induced turbulence and the vertical distribution of dissolved oxygen above and within the sediment were analyzed to evaluate the sediment oxygen uptake rate (JO2), diffusive boundary layer thickness (δDBL), and sediment oxic zone depth (zmax) in situ. High temporal-resolution microprofiles across the sediment-water interface and current velocity data within the bottom boundary layer in a medium-sized mesotrophic lake were obtained during a 12-h field study. We resolved the dynamic forcing of a full 8-h seiche cycle and evaluated JO2 from both sides of the sediment-water interface. Turbulence (characterized by the energy dissipation rate, ε), the vertical distribution of dissolved oxygen across the sediment-water interface (characterized by δDBL and zmax), JO2, and the sediment oxygen consumption rate (RO2) are all strongly correlated in our freshwater system. Seiche-induced turbulence shifted from relatively active (ε = 1.2 × 10-8 W kg-1) to inactive (ε = 7.8 × 10-12 W kg-1). In response to this dynamic forcing, δDBL increased from 1.0 mm to the point of becoming undefined, zmax decreased from 2.2 to 0.3 mm as oxygen was depleted from the sediment, and JO2 decreased from 7.0 to 1.1 mmol m-2 d-1 over a time span of hours. JO2 and oxygen consumption were found to be almost equivalent (within ~ 5% and thus close to steady state), with RO2 adjusting rapidly to changes in JO2. Our results reveal the transient nature of sediment oxygen uptake and the importance of accurately characterizing turbulence when estimating JO2

Serodiagnosis of visceral leishmaniasis in northeastern italy: Evaluation of seven serological tests

This study compares the performance of seven assays, including two ELISA (Leishmania ELISA IgG + IgM, Vircell Microbiologists; Leishmania infantum IgG ELISA, NovaTec), three rK39-based immunochromatographic tests (rK39-ICTs) (Leishmania Dipstick Rapydtest, Apacor; On Site Leishmania IgG/IgM Combo Rapid Test, CTK Biotech; LEISHMANIA Strip quick Test, Cypress Diagnostic), one indirect immunofluorescent antibody test (IFAT) (Leishmania-Spot IF, BioM\ue9rieux), and one western blot (WB) (Leishmania WESTERN BLOT IgG, LDBio Diagnostics) for serodiagnosis of visceral leishmaniasis (VL). Serum samples from 27 VL patients living in northeastern Italy were analyzed, as well as the serum samples from 50 individuals in whom VL diagnosis was excluded. The WB and the IFAT had 96% sensitivity, followed by the ELISA (63% and 74%, respectively). The rK39-ICT exhibited the worst performance among the serological tests, with sensitivities ranging from 52% to 70%. By combining selected ELISA/ICT, the sensitivity of VL detection reached 89%. IFAT and WB outperformed ELISA and rK39-ICT by possessing optimal sensitivity, but their high cost and complexity of execution would not allow their employment as screening tests. In conclusion, the combination of easy-to-perform tests, such as ICT and ELISA, could improve sensitivity in the serodiagnosis of Mediterranean VL

Social and Behavioral Rhythms is Related to the Perception of Quality of Life in Old Adults

Introduction: The purpose is to verify in old adults if social and behavioral rhythms (SBRs) are correlated with a positive perception of the quality of life (QoL). Social and behavioral rhythms and related circadian biorhythms are known as central points in the pathophysiology of bipolar disorders. A secondary aim is to see if a similar relationship can be found in Major Depressive Disorder (MDD) in old adults. Sample: 141 people aged ≥65 years (58.9% Female). Methods: Each subject was evaluated using the Social and Behavioral Rhythms Scale (in which higher scores show more dysfunctional SRBs); SF-12 for QoL and a screening tool for depressive symptoms. They underwent a medical evaluation and blood level assays including cholesterol and triglycerides. The medical diagnoses including MDD were taken into account. Results: The Social and Behavioral Rhythms Scale score correlated inversely with SF-12 score (p<0.001) and positively with PHQ9 (p<0.0001). People with MDD had a higher score on social rhythms than controls without (p<0.01). The study highlighted, for the first time, that social and behavioral rhythms have a role in old adults living in the community. Conclusion: Further longitudinal studies with a sufficient number of individuals will be required to confirm these data and clarify causal links of the association

Moderate exercise improves cognitive function in healthy elderly people: Results of a randomized controlled trial

BACKGROUND: Physical activity in the elderly is recommended by international guidelines to protect against cognitive decline and functional impairment. OBJECTIVE: This Randomized Controlled Trial (RCT) was set up to verify whether medium-intensity physical activity in elderly people living in the community is effective in improving cognitive performance. DESIGN: RCT with parallel and balanced large groups. SETTING: Academic university hospital and Olympic gyms. SUBJECTS: People aged 65 years old and older of both genders living at home holding a medical certificate for suitability in non-competitive physical activity. METHODS: Participants were randomized to a 12-week, 3 sessions per week moderate physical activity program or to a control condition focused on cultural and recreational activities in groups of the same size and timing as the active intervention group. The active phase integrated a mixture of aerobic and anaerobic exercises, including drills of “life movements”, strength and balance. The primary outcome was: any change in Addenbrooke's Cognitive Examination Revised (ACE-R) and its subscales. RESULTS: At the end of the trial, 52 people completed the active intervention, and 53 people completed the control condition. People in the active intervention improved on the ACE-R (ANOVA: F(1;102)=4.32, p=0.040), and also showed better performances on the memory (F(1;102)=5.40 p=0.022) and visual-space skills subscales of the ACE-R (F(1;102)=4.09 p=0.046). CONCLUSION: A moderate-intensity exercise administered for a relatively short period of 12 weeks is capable of improving cognitive performance in a sample of elderly people who live independently in their homes. Clinical Trials Registration No: NCT0385811

Evaluating oxygen fluxes using microprofiles from both sides of the sediment-water interface

Sediment-water fluxes are influenced by both hydrodynamics and sediment biogeochemical processes. However, fluxes at the sediment-water interface (SWI) are almost always analyzed from either a water-or sediment-side perspective. This study expands on previous work by comparing water-side (hydrodynamics and resulting diffusive boundary layer thickness, delta(DBL)) and sediment-side (oxygen consumption and resulting sediment oxic zone) approaches for evaluating diffusive sediment oxygen uptake rate (J(O2)) and delta DBL from microprofiles. Dissolved oxygen microprofile and current velocity data were analyzed using five common methods to estimate J(O2) and delta(DBL) and to assess the robustness of the approaches. Comparable values for J(O2) and delta(DBL) were obtained (agreement within 20%), and turbulence-induced variations in these parameters were uniformly characterized with the five methods. J(O2) estimates based on water-side data were consistently higher (+1.8 mmol m(-2) d(-1) or 25% on average) and delta(DBL) estimates correspondingly lower (-0.4 mm or 35% on average) than those obtained using sediment-side data. This deviation may be attributed to definition of the sediment-water interface location, artifacts of the methods themselves, assumptions made on sediment properties, and/or variability in sediment oxygen-uptake processes. Our work emphasizes that sediment-side microprofile data may more accurately describe oxygen uptake at a particular location, whereas water-side data are representative of oxygen uptake over a broader sediment area. Regardless, our overall results show clearly that estimates of J(O2) and delta(DBL) are not strongly dependent on the method chosen for analysis

Variable sediment oxygen uptake in response to dynamic forcing

Seiche-induced turbulence and the vertical distribution of dissolved oxygen above and within the sediment were analyzed to evaluate the sediment oxygen uptake rate (J(O2)), diffusive boundary layer thickness (delta(DBL)), and sediment oxic zone depth (z(max)) in situ. High temporal-resolution microprofiles across the sediment-water interface and current velocity data within the bottom boundary layer in a medium-sized mesotrophic lake were obtained during a 12-h field study. We resolved the dynamic forcing of a full 8-h seiche cycle and evaluated J(O2) from both sides of the sediment-water interface. Turbulence (characterized by the energy dissipation rate, epsilon), the vertical distribution of dissolved oxygen across the sediment-water interface (characterized by delta(DBL) and z(max)), J(O2), and the sediment oxygen consumption rate (R(O2)) are all strongly correlated in our freshwater system. Seiche-induced turbulence shifted from relatively active (epsilon = 1.2 x 10(-8) W kg(-1)) to inactive (epsilon = 7.8 x 10(-12) W kg(-1)). In response to this dynamic forcing, delta(DBL) increased from 1.0 mm to the point of becoming undefined, z(max) decreased from 2.2 to 0.3 mm as oxygen was depleted from the sediment, and J(O2) decreased from 7.0 to 1.1 mmol m(-2) d(-1) over a time span of hours. J(O2) and oxygen consumption were found to be almost equivalent (within similar to 5% and thus close to steady state), with R(O2) adjusting rapidly to changes in J(O2). Our results reveal the transient nature of sediment oxygen uptake and the importance of accurately characterizing turbulence when estimating J(O2)