Isotopic assessment of CO<Subscript>2</Subscript> production through soil organic matter decomposition in the tropics

Values of ¹³C and ¹⁵N of soil organic matter (SOM) under different land cover in Pasir Mayang, Jambi Province, Sumatra Island, Indonesia were examined to apply them as indicators of SOM dynamics and related CO₂ production. The ¹³C and ¹⁵N values of SOM increased with depth in the 0–30 cm layer in the preserved forest, reflecting ¹³C and ¹⁵N richment in SOM through mineralization and immobilization. The degree of vertical enrichment, difference between 0–5 cm and 10–15 cm SOM, was more pronounced in ¹⁵N than in ¹³C at all sites in Pasir Mayang. The ¹³C -SOM profiles fluctuated through clear-cutting the forest and subsequent burning, which was due to input of biomass with higher C/N molar ratio and lower ¹³C value than the original SOM. However, the ¹⁵N-SOM profiles before and after such a drastic event did not change appreciably. The ¹⁵N-SOM became higher as the C/N ratio decreased and as soil sugar content decreased. These observations suggest that ¹⁵N-SOM is a variable that changes with the amount of easily decomposable organic matter (EDOM) in soil. Soil incubation experiments demonstrated a correlation between CO₂ production rate and degree of vertical ¹⁵N-enrichment in SOM, which was applied to field data to estimate CO₂ production through SOM decomposition. A similar analysis was performed with the soils collected at 27 locations in other districts in Jambi Province than Pasir Mayang. In five locations covered by oil palm plantation, CO₂ production through SOM decomposition controlled 70 of variation in CO₂ emission among the locations. In the remaining 22 locations, however, the CO₂ emission was neither related to CO₂ production from SOM nor to ground litter amount. This observation indicated that mechanisms other than dead organic matter decomposition such as root respiration were dominant sources for CO₂ emission in these sites.     

Unraveling the Binding Mechanism of Alzheimer’s Drugs with Irisin: Spectroscopic,Calorimetric, and Computational Approaches

The prevalence of Alzheimer’s disease (AD) has been a major health concern for a long time. Despite recent progress, there is still a strong need to develop effective disease-modifying therapies. Several drugs have already been approved to retard the progression of AD-related symptoms; however, there is a need to develop an effective carrier system for the delivery of drugs to combat such diseases. In recent years, various biological macromolecules, including proteins, have been used as carriers for drug delivery. Irisin is a beneficial hormone in such diseases, including AD and related pathologies. Herein, the interaction mechanism of irisin with AD drugs such as memantine, galantamine, and fluoxetine is investigated. Fluorescence studies revealed that the above drugs bind to irisin with significant affinity, with fluoxetine having the highest binding affinity. Isothermal titration calorimetry (ITC) complemented the spontaneous binding of these drugs with irisin, delineating various associated thermodynamic and binding parameters. Molecular docking further validated the fluorescence and ITC results and unfolded the mechanism that hydrogen bonding governs the binding of fluoxetine to irisin with a significant binding score, i.e., −6.3 kcal/mol. We believe that these findings provide a promising solution to fight against AD as well as a platform for further research to utilize irisin in the drug-delivery system for an effective therapeutic strategy.     

TLP bonding of Ti-6Al-4V and Mg-AZ31 alloys using pure Ni electro-deposited coats

Transient liquid phase (TLP) bonding of Mg-AZ31 and Ti-6Al-4V alloys was performed using pure thin Ni electro-deposited coat interlayer (12 μm). The effect of bonding temperature, time and pressure on microstructural developments and subsequent mechanical properties across joint interface was studied at a temperature range from 500 to 540 °C, bonding time from 1 to 60 min and bonding pressure from 0 to 0.8 MPa. The mechanisms of bond formation varied across the joint region, with solid-state diffusion dominant at the Ti-6Al-4V interface and eutectic diffusion at the Mg-AZ31 interface. Joint microstructure was examined by scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). X-ray diffraction (XRD) was used to detect the formation of intermetallic phases at the fracture surface. The maximum joint shear strength of 61 MPa was obtained at a temperature of 520 °C, 20 min and at a bonding pressure of 0.2 MPa. This joint strength was three times the bond strength reported for joints made using adhesives and represents 50% of the Mg-AZ31 alloy shear strength.     

Potential Activity of Fevicordin-A from Phaleria macrocarpa (Scheff) Boerl. Seeds as Estrogen Receptor Antagonist Based on Cytotoxicity and Molecular Modelling Studies

Fevicordin-A (FevA) isolated from Phaleria macrocarpa (Scheff) Boerl. seeds was evaluated for its potential anticancer activity by in vitro and in silico approaches. Cytotoxicity studies indicated that FevA was selective against cell lines of human breast adenocarcinoma (MCF-7) with an IC₅₀ value of 6.4 μM. At 11.2 μM, FevA resulted in 76.8% cell death of T-47D human breast cancer cell lines. Critical pharmacophore features amongst human Estrogen Receptor-α (hERα) antagonists were conserved in FevA with regard to a hypothesis that they could make notable contributions to its pharmacological activity. The binding stability as well as the dynamic behavior of FevA towards the hERα receptor in agonist and antagonist binding sites were probed using molecular dynamics (MD) simulation approach. Analysis of MD simulation suggested that the tail of FevA was accountable for the repulsion of the C-terminal of Helix-11 (H11) in both agonist and antagonist receptor forms. The flexibility of loop-534 indicated the ability to disrupt the hydrogen bond zipper network between H3 and H11 in hERα. In addition, MM/GBSA calculation from the molecular dynamic simulations also revealed a stronger binding affinity of FevA in antagonistic action as compared to that of agonistic action. Collectively, both the experimental and computational results indicated that FevA has potential as a candidate for an anticancer agent, which is worth promoting for further preclinical evaluation.     

Probability of detecting and quantifying faecal contaminations of drinking water by periodically sampling for E. coli: a simulation model study

Drinking water supply companies monitor the presence of Escherichia coli in drinking water to verify the effectiveness of measures that prevent faecal contamination of drinking water. Data are lacking, however, on the sensitivity of the monitoring programmes, as designed under the EU Drinking Water Directive. In this study, the sensitivity of such a monitoring programme was evaluated by hydraulic model simulations of contamination events and calculations of the detection probability of the actual sampling programme of 2002. In the hydraulic model simulations of 16-h periods of 1l h(-1) ingress of untreated domestic sewage, the spread of the contamination through the network and the E. coli concentration dynamics were calculated. The results show that when large parts of the sewage reach reservoirs, e.g. when they originate from the treatment plant or a trunk main, mean detection probabilities are 55-65%. When the contamination does not reach any of the reservoirs, however, the detection probability varies from 0% (when no sampling site is reached) to 13% (when multiple sites are reached). Mean detection probabilities of nine simulated ingress incidents in mains are 5.5% with an SD of 6.5%. In reality, these detection probabilities are probably lower as the study assumed no inactivation or clustering of E. coli, 100% recovery efficiency of the E. coli detection methods and immediate mixing of contaminations in mains and reservoirs. The described method provides a starting point for automated evaluations and optimisations of sampling programmes.     

Dynamic forecasting of travel demand,residential location and land development

TheChicago Area Transportation/Land-Use Analysis System (CATLAS) is a large scale urban simulation model which synthesizes location rent analysis from urban economics with travel demand analysis from transportation planning. This paper describes the theoretical formulation, empirical estimation and policy application of CATLAS to the evaluation of CBD-oriented rapid transit projects in Chicago.     

Microfluidic multi-target sorting by magnetic repulsion

In magnetophoresis-based microfluidic systems, the free-flow sorting is achieved by incrementally navigating the magnetic target toward a designated outlet. This is typically enabled using high-gradient magnetic concentrators (HGMCs), axially aligned or slightly slanted with the streaming sample flow. Such axial and incremental magnetic manipulation critically constraints the throughput and the number of targets that can be sorted simultaneously. To overcome these constraints, we present an alternative repulsion-based sorting method. The repulsion force is due that induced, over a limited angular expanse, around a single ferromagnetic wire. The wire is positioned transversally against the focused sample flow. Differentially repelled by the repulsive force, each target deflects from its focused path to follow a ribbon-like trajectory that leads to a spatially addressable outlet. The mediated sorting takes place more rapidly and is confined to the region facing the transversal wire. More importantly, the introduced concept design allows for a throughput that is geometrically scalable with the length of the wire. The functionality of the systems is demonstrated experimentally and numerically to yield the simultaneous and complete multi-target sorting of two and more magnetic beads.     

Slab waveguide with conducting interfaces as an efficient optical sensor: TE case

In this paper, three-layer slab waveguide structure is treated for optical sensing applications. Four waveguide configurations including different guiding films and analytes are assumed. A conducting two-dimensional free charge layers with a surface conductivity is assumed to exist at the substrate/film and film/cladding interfaces. The sensing sensitivity of the proposed structure to any changes in an analyte refractive index uniformly distributed in the cladding layer is investigated. Positive as well as negative surface conductivities are considered. It is found that utilizing positive surface conductivity can enhance the sensitivity, whereas using negative values of the surface conductivity reduces the sensitivity.