Traveling length and minimal traveling time for flow through percolation networks with long-range spatial correlations

We study the distributions of traveling length l and minimal traveling time t through two-dimensional percolation porous media characterized by long-range spatial correlations. We model the dynamics of fluid displacement by the convective movement of tracer particles driven by a pressure difference between two fixed sites (''wells'') separated by Euclidean distance r. For strongly correlated pore networks at criticality, we find that the probability distribution functions P(l) and P(t) follow the same scaling Ansatz originally proposed for the uncorrelated case, but with quite different scaling exponents. We relate these changes in dynamical behavior to the main morphological difference between correlated and uncorrelated clusters, namely, the compactness of their backbones. Our simulations reveal that the dynamical scaling exponents for correlated geometries take values intermediate between the uncorrelated and homogeneous limiting cases

Energy Harvesting Opportunities in Geoenvironmental Engineering

Geoenvironmental engineering involves defining solutions for complex problems, such as containment systems management, contaminant transport control, wastewater management, remediation of contaminated sites and valorization of geomaterials and wastes. In the last years, energy harvesting (EH)—or energy scavenging—methods and technologies have been developed to reduce the dependence on traditional energy sources, namely fossil fuels, and nuclear power, also responding to the increase in energy demands for human activities and to fulfill sustainable development goals. EH in geoenvironmental works and the surrounding soil and water environment includes a set of processes for capturing and accumulating energy from several sources considered wasted or unusable associated with soil dynamics; the stress and strain of geomaterials, hydraulic, vibrations, biochemical, light, heating and wind sources can be potential EH systems. Therefore, this work presents a review of the literature and critical analysis on the main opportunities for EH capturing, accumulating and use in geoenvironmental works, among basic electric concepts and mechanisms, analyzing these works in complex conditions involving biological-, chemical-, mechanical-, hydraulic- and thermal-coupled actions, concluding with the main investigation and challenges within geoenvironmental aspects for EH purposes.info:eu-repo/semantics/publishedVersio

The Atp-dependent Rna Helicase Hrpb Plays An Important Role In Motility And Biofilm Formation In Xanthomonas Citri Subsp. Citri

Background: RNA helicases are enzymes that catalyze the separation of double-stranded RNA (dsRNA) using the free energy of ATP binding and hydrolysis. DEAD/DEAH families participate in many different aspects of RNA metabolism, including RNA synthesis, RNA folding, RNA-RNA interactions, RNA localization and RNA degradation. Several important bacterial DEAD/DEAH-box RNA helicases have been extensively studied. In this study, we characterize the ATP-dependent RNA helicase encoded by the hrpB (XAC0293) gene using deletion and genetic complementation assays. We provide insights into the function of the hrpB gene in Xanthomonas citri subsp. citri by investigating the roles of hrpB in biofilm formation on abiotic surfaces and host leaves, cell motility, host virulence of the citrus canker bacterium and growth in planta. Results: The hrpB gene is highly conserved in the sequenced strains of Xanthomonas. Mutation of the hrpB gene (Δ;hrpB) resulted in a significant reduction in biofilms on abiotic surfaces and host leaves. Δ;hrpB also exhibited increased cell dispersion on solid medium plates. Δ;hrpB showed reduced adhesion on biotic and abiotic surfaces and delayed development in disease symptoms when sprayed on susceptible citrus leaves. Quantitative reverse transcription-PCR assays indicated that deletion of hrpB reduced the expression of four type IV pili genes. The transcriptional start site of fimA (XAC3241) was determined using rapid amplification of 5′-cDNA Ends (5′RACE). Based on the results of fimA mRNA structure predictions, the fimA 5′ UTR may contain three different loops. HrpB may be involved in alterations to the structure of fimA mRNA that promote the stability of fimA RNA. Conclusions: Our data show that hrpB is involved in adherence of Xanthomonas citri subsp. citri to different surfaces. In addition, to the best of our knowledge, this is the first time that a DEAH RNA helicase has been implicated in the regulation of type IV pili in Xanthomonas. © 2016 Granato et al.16

Reproducibility of hemodynamic, cardiac autonomic modulation and blood flow assessments in patients with intermittent claudication

Objective: To identify, in patients with peripheral artery disease and intermittent claudication (IC), the reproducibility of heart rate (HR), blood pressure (BP), rate pressure product (RPP), heart rate variability (HRV), and forearm and calf blood flow (BF) and vasodilatory assessments. Methods: Twenty-nine patients with IC underwent test and retest sessions, 8-12 days apart. During each session, HR, BP, HRV, BF and vasodilatory responses were measured by electrocardiogram, auscultation, spectral analysis of HRV (low frequency, LFR-R; high frequency, HFR-R) and strain gauge plethysmography (baseline BF, post-occlusion BF, post-occlusion area under the curve, AUC). Reproducibility was determined by intraclass coefficient correlation (ICC), typical error, coefficient of variation (CV) and limits of agreement. Results: The ICC for HR and BP were > 0.8 with CV 0.9 while CV were 0.9 while CV were < 19%; variable ICC and CV for vasodilatory responses were exhibited for calf (0.653 – 0.770; 35.2 – 37.7%) and forearm (0.169 – 0.265; 46.2 – 55.5%). Conclusions: In male patients with IC, systemic hemodynamic (HR and BP), cardiac autonomic modulation (LFR-R and HFR-R) and forearm and calf baseline BF assessments exhibited excellent reproducibility, whereas the level of reproducibility for vasodilatory responses were moderate to poor. Assessment reproducibility has highlighted appropriate clinical tools for the regular monitoring of disease/intervention progression in patients with IC

Walking training improves systemic and local pathophysiological processes in intermittent claudication

Objective: This study examined the impact of submaximal walking training (WT) on local and systemic nitric oxide (NO) bioavailability, inflammation, and oxidative stress in patients with intermittent claudication (IC). Methods: The study employed a randomised, controlled, parallel group design and was performed in a single centre. Thirty-two men with IC were randomly allocated to two groups: WT (n = 16, two sessions/week, 15 cycles of two minutes walking at an intensity corresponding to the heart rate obtained at the pain threshold interspersed by two minutes of upright rest) and control (CO, n = 16, two sessions/week, 30 minutes of stretching). NO bioavailability (blood NO and muscle nitric oxide synthase [eNOS]), redox homeostasis (catalase [CAT], superoxide dismutase [SOD], lipid peroxidation [LPO] measured in blood and muscle), and inflammation (interleukin-6 [IL-6], C-reactive protein [CRP], tumour necrosis factor α [TNF-α], intercellular adhesion molecules [ICAM], vascular adhesion molecules [VCAM] measured in blood and muscle) were assessed at baseline and after 12 weeks. Results: WT statistically significantly increased blood NO, muscle eNOS, blood SOD and CAT, and muscle SOD and abolished the increase in circulating and muscle LPO observed in the CO group. WT decreased blood CRP, ICAM, and VCAM and muscle IL-6 and CRP and eliminated the increase in blood TNF-α and muscle TNF-α, ICAM and VCAM observed in the CO group. Conclusion: WT at an intensity of pain threshold improved NO bioavailability and decreased systemic and local oxidative stress and inflammation in patients with IC. The proposed WT protocol provides physiological adaptations that may contribute to cardiovascular health in these patients

Walking Training Increases microRNA-126 Expression and Muscle Capillarization in Patients with Peripheral Artery Disease

Patients with peripheral artery disease (PAD) have reduced muscle capillary density. Walking training (WT) is recommended for PAD patients. The goal of the study was to verify whether WT promotes angiogenesis in PAD-affected muscle and to investigate the possible role of miRNA-126 and the vascular endothelium growth factor (VEGF) angiogenic pathways on this adaptation. Thirty-two men with PAD were randomly allocated to two groups: WT (n = 16, 2 sessions/week) and control (CO, n = 16). Maximal treadmill tests and gastrocnemius biopsies were performed at baseline and after 12 weeks. Histological and molecular analyses were performed by blinded researchers. Maximal walking capacity increased by 65% with WT. WT increased the gastrocnemius capillary-fiber ratio (WT = 109 ± 13 vs. 164 ± 21 and CO = 100 ± 8 vs. 106 ± 6%, p < 0.001). Muscular expression of miRNA-126 and VEGF increased with WT (WT = 101 ± 13 vs. 130 ± 5 and CO = 100 ± 14 vs. 77 ± 20%, p < 0.001; WT = 103 ± 28 vs. 153 ± 59 and CO = 100 ± 36 vs. 84 ± 41%, p = 0.001, respectively), while expression of PI3KR2 decreased (WT = 97 ± 23 vs. 75 ± 21 and CO = 100 ± 29 vs. 105 ± 39%, p = 0.021). WT promoted angiogenesis in the muscle affected by PAD, and miRNA-126 may have a role in this adaptation by inhibiting PI3KR2, enabling the progression of the VEGF signaling pathway

Circulating adrenomedullin in cirrhosis: relationship to hyperdynamic circulation

BACKGROUND/AIMS: Peripheral arterial vasodilation may be the key factor in the sodium and water retention of cirrhosis. The mechanism responsible for this vasodilation remains to be fully elucidated. Adrenomedullin is a novel peptide, highly expressed in cardiovascular tissues, with potent and long-lasting vasodilating activity. METHODS: The possible implication of adrenomedullin in the hemodynamic changes of cirrhosis has been investigated. We measured the plasma concentration of adrenomedullin in 20 cirrhotic patients and 11 healthy subjects. In addition, systemic, portal and renal hemodynamics, hormonal factors and renal function parameters were evaluated in the same patients. RESULTS: Circulating adrenomedullin was significantly higher in the group of patients with cirrhosis (72.1; 46-100 vs 21.6; 11-34 fmol/dl, respectively; p<0.02) and was directly correlated with the Pugh score (r: 0.6; p: 0.01), inversely correlated with the creatinine clearance (r: -0.6; p<0.01) and tended to inversely correlate with systemic vascular resistance index (r: -0.46; p: 0.07). There were no portal-peripheral differences in adrenomedullin levels. Transjugular intrahepatic portosystemic shunt insertion did not induce changes in the peripheral concentration of adrenomedullin, but baseline values of this hormone predicted the degree of hyperdynamic circulation after TIPS. CONCLUSIONS: Circulating adrenomedullin is increased in cirrhosis. These levels increase with the severity of the disease, especially in patients with hepatorenal syndrome. This peptide may contribute to vasodilation of cirrhosis

Low-intensity resistance exercise does not affect cardiac autonomic modulation in patients with peripheral artery disease

OBJECTIVE: To analyze the effect of a single bout of resistance exercise on cardiac autonomic modulation in patients with peripheral artery disease. METHODS: Fifteen patients with peripheral artery disease (age: 58.3±4.0 years) underwent the following sessions in a random order: resistance exercise (three sets of 10 repetitions of the six resistance exercises with a workload of 5-7 in the OMNI-RES scale) and control (similar to the resistance session; however, the resistance exercises were performed with no load). The frequency domain (low frequency, high frequency and sympathovagal balance) and symbolic analysis (0V, 1V and 2V patterns) of heart rate variability were obtained before and until one hour after the interventions. RESULTS: After the resistance exercise and control sessions, similar increases were observed in the consecutive heartbeat intervals (control: 720.8±28.6 vs. 790.9±34.4 ms; resistance exercise: 712.9±30.1 vs. 756.8±37.9 ms;

Long-term Outcomes in a Large Randomized Trial of HIV-1 Salvage Therapy: 96-Week Results of AIDS Clinical Trials Group A5241 (OPTIONS)

Background: Short-term (48-week) results of the OPTIONS trial showed that nucleoside reverse transcriptase inhibitors (NRTIs) can be safely omitted from salvage therapy as long as the regimen has a cumulative activity of >2 active antiretroviral medications. The long-term durability of this approach and outcomes in persons who have more-extensive HIV-1 drug resistance are uncertain. Methods: Participants with virologic failure and anticipated antiretroviral susceptibility received an optimized regimen and were randomized to omit or add NRTIs. A separate group with more resistance (cumulative activity ≤2 active agents) received an optimized regimen including NRTIs. Results: At week 96, among 360 participants randomized to omit or add NRTIs, 70% and 65% had HIV-1 RNA 2 active drugs. Younger people and those receiving fewer new antiretrovirals require careful monitoring. Even among individuals with more-extensive resistance, most achieve virologic suppression. Clinical Trials Registration: NCT00537394