The Internet of Things (IoT) opens opportunities for wearable devices, home appliances, and software to share and communicate information on the Internet. Given that the shared data contains a large amount of private information, preserving information security on the shared data is an important issue that cannot be neglected. In this paper, we begin with general information security background of IoT and continue on with information security related challenges that IoT will encountered. Finally, we will also point out research directions that could be the future work for the solutions to the security challenges that IoT encounters.

The effect of shear alone on the aggregation of recombinant human growth hormone (rhGH) and recombinant human deoxyribonuclease (rhDNase) has been found to be insignificant. This study focused on the synergetic effect of shear and gas‐liquid interface on these two model proteins. Two shearing systems, the concentric‐cylinder shear device (CCSD) and the rotor/stator homogenizer, were used to generate high shear (> 106) in aqueous solutions in the presence of air. High shear in the presence of an air‐liquid interface had no major effect on rhDNase but caused rhGH to form noncovalent aggregates. rhGH aggregation was induced by the air‐liquid interface and was found to increase with increasing protein concentration and the air‐liquid interfacial area. The aggregation was irreversible and exhibited a first‐order kinetics with respect to the protein concentration and air‐liquid interfacial area. Shear and shear rate enhanced the interaction because of its continuous generation of new air‐liquid interfaces. In the presence of a surfactant, aggregation could be delayed or prevented depending upon the type and the concentration of the surfactant. The effect of air‐liquid interface on proteins at low shear was examined using a nitrogen bubbling method. We found that foaming is very detrimental to rhGH even though the shear involved is low. The use of anti‐foaming materials could prevent rhGH aggregation during bubbling. The superior stability exhibited by rhDNase may be linked to the higher surface tension and lower foaming tendency of its aqueous solution. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 503–512, 1997.

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We have investigated the effect of mannitol, sorbitol, methyl alpha-D-mannopyranoside, lactose, trehalose, and cellobiose on the stability and structure of the pharmaceutical protein recombinant human growth hormone (rhGH) in the lyophilized state. All excipients afforded significant protection of the protein against aggregation, particularly at levels to potentially satisfy water-binding sites on the protein in the dried state (i.e., 131:1 excipient-to-protein molar ratio). At higher excipient-to-protein ratios, X-ray diffraction studies showed that mannitol and sorbitol were prone to crystallization and afforded somewhat less stabilization than at lower ratios where the excipient remained in the amorphous, protein-containing phase. The secondary structure of rhGH was determined using Fourier transform infrared (FTIR) spectroscopy. rhGH exhibited a decrease in alpha-helix and increase in beta-sheet structures upon drying. Addition of excipient stabilized the secondary structure upon lyophilization to a varying extent depending on the formulation. Samples with a significant degree of structural conservation, as indicated by the alpha-helix content, generally exhibited reduced aggregation. In addition, prevention of protein-protein interactions (indicated by reduced beta-sheet formation) also tended to result in lower rates of aggregation. Therefore, in addition to preserving the protein structure, bulk additives that do not crystallize easily and remain amorphous in the solid state can be used to increase protein-protein distance and thus prevent aggregation.

The purpose of this research was to investigate the shape and morphology of various spray-dried protein powders as a function of spray-drying conditions and protein formulations. A benchtop spray dryer was used to spray dry three model proteins in formulation with a sugar or a surfactant. Physical characterizations of the powder included morphology (scanning electron microscopy), particle size, residual moisture, and X-ray powder diffraction analyses. A significant change in particle shape from irregular (e.g., "donut") to spherical was observed as the outlet temperature of the dryer was decreased. The drying air outlet temperature was shown to depend on various operating parameters and was found to correlate with the drying rate of atomized droplets in the drying chamber. The morphology of spray-dried protein particles was also affected by formulation. In protein:sugar formulations, spray-dried particles exhibited a smooth surface regardless of the protein-to-lactose ratio, whereas roughness was observed when mannitol was present at > 30% of total solids, due to recrystallization. Protein particles containing trehalose at concentrations > 50% were highly agglomerated. The presence of surfactant resulted in noticeably smoother, more spherical particles. The shape and the morphology of spray-dried powders are affected by spray drying conditions and protein formulation. This study provides information useful for development of dry proteins for fine powder (e.g., aerosol) applications.