The role of context in overcoming distance-related problems in global virtual teams: An organizational discontinuity theory perspective

Working at a distance has become a hot topic since the outbreak of the COVID-19 pandemic. One type of work unit that naturally faces both physical and social distance is the Global Virtual Teams (GVT). While distance has been debated in the GVT literature, there is still a scarcity of research on how to deal with distance related problems. Guided by organizational discontinuity theory, we explore the effect of individual-level approaches to overcoming physical distance (time zone adjustment) and social distance (trust in peers) in GVTs. In addition, we assess how these mechanisms are affected by the team context in the form of openness to cultural diversity. We do this by studying 23 GVTs (171 team members and 23 team leaders) in the global R&D department of a Danish engineering company. Our findings demonstrate that trust in peers is positively associated with job role clarity and job performance at the individual-level, and that high team openness to diversity, in the case of performance, makes the individual’s level of trust in peers less necessary for achieving performance. Our results also show that time zone adjustment increases job role clarity for the individual team member, but only in GVTs with high openness to cultural diversity. Based on this, we contribute to the organizational discontinuity theory by demonstrating how continuity-creating mechanisms can interact with the team context to ultimately support the individual’s potential for handling distance in GVTs

Magnetic hyperthermia study of magnetosome chain systems in tissue-mimicking phantom

Magnetosomes produced by magnetotactic bacteria are biological membrane-enveloped magnetic nanoparticles. Extracted magnetosomes having the form of long chains as well as shortened chains with individual magnetosomes were prepared. The morphology (chain sizes) was modified in the sonication process and its impact was studied by transmission electron microscopy and dynamic light scattering. Fast magnetization saturation of magnetosome samples and the Verwey transition were detected by temperature-dependent magnetization measurements. To study the heating response to the applied alternating magnetic field (magnetic hyperthermia) magnetosomes were added into tissue-mimicking phantom. Temperature evolution and specific absorption rate (SAR) were measured and analyzed. It was found that embedding magnetosome chains in gel phantoms lead to a noticeable decrease in the efficiency of heating due to deterioration of Brownian mechanism

Elimination of Magnetic Nanoparticles with Various Surface Modifications from the Bloodstream in vivo

The magnetic nanoparticles with the core diameter 10 nm stabilized by sodium oleate and bovine serum albumin in phosphate buffer have been modified by different biocompatible substances such as poly(ethylene glycol) (PEG), dextran (DEX), and polyvinylpyrrolidone (PVP). Prepared biocompatible magnetic fluids were characterized to obtain the particle size distribution using scanning electron microscopy and the dynamic light scattering method. To study the elimination of different modified magnetic nanoparticles from bloodstream, the biocompatible samples were applied intravenously to the mice bloodstream with further blood specimens collecting in given time intervals. Magnetic moment of the lyophilized blood samples was measured by SQUID magnetometer. Time dependence of magnetic moment of magnetic nanoparticles and magnetic nanoparticles modified by DEX, PEG and PVP normalized to the Fe₃O₄ showed that the circulation time of magnetic nanoparticles in the bloodstream depends on the substance used for modification. The unmodified magnetic nanoparticles were trapped by reticuloendothelial system within 1 h while magnetic nanoparticles modified by DEX, PEG and PVP circulated in blood up to 3 h

Energy losses in mechanically modified bacterial magnetosomes

Magnetosomes are isolated from the Magnetospirillum magneticum strain AMB-1 bacteria. Two samples are compared: magnetosomes normally prepared of a ‘standard’ length and magnetosomes of a short length. Chains of magnetosomes are shortened by mechanical modification (cleavage) by means of sonication treatment. They represent a new geometry of magnetosomes that have not been investigated before. The effect of the sonication is analysed using transmission and electron microscopy, atomic force microscopy, and dynamic light scattering. Scanning imaging reveals three types of shortening effect in a sample of shortened magnetosomes, namely, membrane collapse, membrane destruction, and magnetosome cleavage. Dynamic light scattering shows a reduction of hydrodynamic diameter in a sample of shortened magnetosomes. The magnetic properties of magnetosomes are analysed and compared in DC and AC magnetic fields based on the evaluation of quasi-static hysteresis loops (energy losses) and calorimetric hyperthermia measurements (specific absorption rate), respectively. A sample of shortened magnetosomes behaves magnetically in a different manner, showing that both the energy loss and the specific absorption rate are reduced, and thereby indicates a variation in the heating process. The magnetic properties of magnetosomes, together with the new and stable geometry, are balanced, which opens the way for a better adaptation of the magnetic field parameters for particular applications

Presence of Magnetic Fluids Leads to the Inhibition of Insulin Amyloid Aggregation

Insulin amyloid aggregation caused serious problems in the treatment of diabetes by insulin injection or by insulin pumps. In vitro formation of insulin amyloid fibrils was investigated in presence of several types of magnetic fluids. Interaction of magnetic fluids with insulin amyloid aggregates led to decrease of insulin fibrillization. The inhibiting activities are affected by coating layer of studied magnetic fluids as well as by their physical properties (diameter, concentration of magnetic particles). The highest inhibiting efficiencies were detected for sterically stabilized magnetic fluids in saline solution (75%) and for magnetic fluids modified by dextran (80%)

Preparation and Characterization of Magnetic Nanoparticles

The magnetic nanoparticles with core diameter 10 nm were modified by poly-L-lysine to bind antibody for cancer cell detection. Prepared biocompatible magnetic fluid (MFPLL) was characterized by dynamic light scattering method to obtain the particle size distribution. The microstructure of the MNPs and MFPLL samples were studied by transmission electron microscopy, X-ray diffraction and Mössbauer spectroscopy. Magnetic properties of the samples were measured by SQUID magnetometer and superparamagnetic behaviour of the samples was confirmed

Development of Positively Charged Poly-L-Lysine Magnetic Nanoparticles as Potential MRI Contrast Agent

A colloidal solution of magnetic nanoparticles (MNPs) modified with biocompatible positively charged poly-L-lysine (PLL) with an oleate (OL) layer employed as an initial coating was produced as a potential MRI contrast agent. The effect of various PLL/MNPs’ mass ratios on the samples’ hydrodynamic diameter, zeta potential, and isoelectric point (IEP) was studied by the dynamic light-scattering method. The optimal mass ratio for MNPs’ surface coating was 0.5 (sample PLL0.5-OL-MNPs). The average hydrodynamic particle size in the sample of PLL0.5-OL-MNPs was 124.4 ± 1.4 nm, and in the PLL-unmodified nanoparticles, it was 60.9 ± 0.2 nm, indicating that the OL-MNPs’ surface became covered by PLL. Next, the typical characteristics of the superparamagnetic behavior were observed in all samples. In addition, the decrease in saturation magnetizations from 66.9 Am2/kg for MNPs to 35.9 and 31.6 Am2/kg for sample OL-MNPs and PLL0.5-OL-MNPs also confirmed successful PLL adsorption. Moreover, we show that both OL-MNPs and PLL0.5-OL-MNPs exhibit excellent MRI relaxivity properties and a very high r2(*)/r1 ratio, which is very desirable in biomedical applications with required MRI contrast enhancement. The PLL coating itself appears to be the crucial factor in enhancing the relaxivity of MNPs in MRI relaxometry