Task-Related modulations of BOLD low-frequency fluctuations within the default mode Network

Spontaneous low-frequency Blood-Oxygenation Level-Dependent (BOLD) signals acquired during resting state are characterized by spatial patterns of synchronous fluctuations, ultimately leading to the identification of robust brain networks. The resting-state brain networks, including the Default Mode Network (DMN), are demonstrated to persist during sustained task execution, but the exact features of task-related changes of network properties are still not well characterized. In this work we sought to examine in a group of 20 healthy volunteers (age 33 ± 6 years, 8 F/12 M) the relationship between changes of spectral and spatiotemporal features of one prominent resting-state network, namely the DMN, during the continuous execution of a working memory n-back task. We found that task execution impacted on both functional connectivity and amplitude of BOLD fluctuations within large parts of the DMN, but these changes correlated between each other only in a small area of the posterior cingulate. We conclude that combined analysis of multiple parameters related to connectivity, and their changes during the transition from resting state to continuous task execution, can contribute to a better understanding of how brain networks rearrange themselves in response to a task

An effective long-range attraction between protein molecules in solutions studied by small angle neutron scattering

Small angle neutron scattering intensity distributions taken from cytochrome C and lysozyme protein solutions show a rising intensity at very small wave vector, Q, which can be interpreted in terms of the presence of a weak long-range attraction between protein molecules. This interaction has a range several times that of the diameter of the protein molecule, much greater than the range of the screened electrostatic repulsion. We show evidence that this long-range attraction is closely related to the type of anion present and ion concentration in the solution

Conformational changes and location of BSA upon immobilization on zeolitic imidazolate frameworks

The location and the conformational changes of proteins/enzymes immobilized within Metal Organic Frameworks (MOFs) are still poorly investigated and understood. Bovine serum albumin (BSA), used as a model protein, was immobilized within two different zeolitic imidazolate frameworks (ZIF-zni and ZIF-8). Pristine ZIFs and BSA@ZIFs were characterized by X-ray diffraction, small-angle X-ray scattering, scanning electron microscopy, confocal laser scanning microscopy, thermogravimetric analysis, micro-FTIR and confocal Raman spectroscopy to characterize MOFs structure and the protein location in the materials. Moreover, the secondary structure and conformation changes of BSA after immobilization on both ZIFs were studied with FTIR. BSA is located both in the inner and on the outer surface of MOFs, forming domains that span from the micro- to the nanoscale. BSA crystallinity (β-sheets + α-helices) increases up to 25 % and 40 % due to immobilization within ZIF-zni and ZIF-8, respectively, with a consequent reduction of β-turns

Influence of feedstock and operational conditions on bio-chars derived from the pyrolysis of selected biomasses

The proprieties of bio-char, the solid product from biomass pyrolysis, depends on both the feedstock and process conditions during thermochemical conversion[1]. As regards the interaction of the char with soil (i.e. as soil amendment), surface areas, size and shape of pores are among the most important factors to be considered. [1] P. R. Bonelli , G. Nunell , M. E. Fernández , E. L. Buonomo & A. L. Cukierman (2012) The Potential Applications of the Bio-char Derived from the Pyrolysis of an Agro-industrial Waste. Effects of Temperature and Acid-pretreatment, Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 34:8, 746-755, DOI: 10.1080/15567031003681937 Please click Additional Files below to see the full abstract

Hydration-dependent dynamic crossover phenomenon in protein hydration water

The characteristic relaxation time τ of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level h[subscript c] =0.2–0.25 and becomes more visible as h increases. When h is lower than h[subscript c], τ only exhibits Arrhenius behavior in the measured temperature range. The activation energy of the Arrhenius behavior is insensitive to h, indicating a local-like motion. Moreover, the h dependence of the crossover temperature shows that the protein dynamic transition is not directly or solely induced by the dynamic crossover in the hydration water.United States. Dept. of Energy. Office of Basic Energy Sciences (Contract DE-FG02-90ER45429