Effects of Spray Drying Temperature and Additives on the Stability of Serine Alkaline Protease Powders

In this study, after production by recombinant Bacillus subtilis (BGSC-1A751), carrying pHV1431::subc gene in the complex medium and separation of solids from the fermentation broth, serine alkaline protease (SAP) was dried in order to investigate the stabilization during spray drying and subsequent storage. The effect of air inlet temperature of the spray dryer between T = 70 and 130°C and the effect of protective additives, glucose and maltodextrin, at 0–2% (w/v) on SAP activity during spray drying and storage stability of obtained SAP powders at 4°C for a long period (6 months) were evaluated. Increasing drying air inlet temperature generally resulted in an increase in activity loss; moreover, higher absorbance peaks observed at wave number 1061 cm^?1 of the IR spectrums when drying temperature is increased indicates the structural change in the SAP molecule. In most cases presence of additives provided higher activities both after drying and during storage period compared to no additive case. Drying the enzyme with 1% (w/v) glucose at T = 110°C resulted in the highest enzyme activity after drying and storage processes.     

Synthesis of hydroxy-terminated polytetrahydrofuran by photoinduced process

Summary This paper describes the preparation of hydroxy-functional telechelics by photoinduced decomposition of polytetrahydrofuran possessing terminal pyridinium ions in THF solution. Hydroxyl functionality was evidenced by end capping and polycondensation with isocyanates.     

Guanine oxidation signal enhancement in single strand DNA with polyacrylonitrile/polyaniline (PAN/PAni) hybrid nanofibers

Pure polyacrylonitrile (PAN) and polyacrylonitrile/polyaniline (PAN/PAni) hybrid nanofibers (NFs) were produced via electrospinning and used to monitor guanine oxidation in single strand DNA (ssDNA) by electrochemical methods. Two different methodologies were conducted. First, pre‐synthesized PAni was added into electrospinning PAN solution and electrospun into composite PAN/PAni nanofibrous structure on cylindrical pencil graphite (PGE) surface. In the second route, PAN NFs were electrospun on a PGE surfaces and polymerization of PAni was conducted on the surfaces of the as‐spun PAN NFs. NFs were kept at ?18 °C in a refrigerator for several days. ssDNA was immobilized on the prepared NFs and guanine oxidation signals were observed for each system. The results revealed that use of PAN NFs enhanced signal intensity from 0.92 µA (PGE) to 1.04 µA (PAN NFs). Addition of PAni to PAN increased signal intensity to 1.23 µA. When the PAN NF surfaces were coated with PAni, signal enhancement continued to increase up to 4.19 µA for fourth day and decreased again when PAni‐coated NFs were kept at ?18 °C in the refrigerator. Since the prepared system is fast and cheap, it is promising for application in DNA biosensor devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45567.     

Adsorption of IgG on spacer‐arm and L‐arginine ligand attached poly(GMA/MMA/EGDMA) beads

This work presents data on human immunoglobulin G (HIgG) adsorption onto L ‐arginine ligand attached poly(GMA/MMA/EGDMA)‐based affinity beads which were synthesized from methyl methacrylate (MMA) and glycidiyl methacrylate (GMA) in the presence of a crosslinker (i.e., ethylene glycol dimethacrylate; EGDMA) by suspension polymerization. The epoxy groups of the poly(GMA/MMA/EGDMA) beads were converted into amino groups after reaction with ammonia or 1,6‐diaminohexane (i.e., spacer‐arm). With L ‐arginine as a ligand, it was covalently immobilized on the aminated (poly(GMA/MMA/EGDMA)‐ AA) and/or the spacer‐arm attached (poly(GMA/MMA/EGDMA)‐SA) beads, using glutaric dialdehyde as a coupling agent. Both affinity poly(GMA/MMA/EGDMA)‐based beads were used in HIgG adsorption/desorption studies under defined pH, ionic strength, or temperature conditions in a batch reactor, using acid‐treated poly(GMA/MMA/EGDMA) beads as a control system. The poly(GMA/MMA/EGDMA)‐SA affinity beads resulted in an increase in the adsorption capacity to HIgG compared with the aminated counterpart (i.e., poly(GMA/MMA/EGDMA)‐AA). The maximum adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA affinity beads were found to be 112.36 and 142 mg g^?1, and the affinity constants (K_d), evaluated by the Langmuir model, were 2.48 × 10^?7 and 6.98 × 10^?7M, respectively. Adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA were decreased with HIgG by increasing the ionic strength adjusted with NaCl. Adsorption kinetic of HIgG onto both affinity adsorbents was analyzed with first‐ and second‐order kinetic equations. The first‐order equation fitted well with the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 672–679, 2007     

Multiscale characterization of pathological bone tissue

Bone is a complex natural material with a complex hierarchical multiscale organization, crucial to perform its functions. Ultrastructural analysis of bone is crucial for our understanding of cell to cell communication, the healthy or pathological composition of bone tissue, and its three-dimensional (3D) organization. A variety of techniques has been used to analyze bone tissue. This article describes a combined approach of optical, scanning electron, and transmission electron microscopy for the ultrastructural analysis of bone from the nanoscale to the macroscale, as illustrated by two pathological bone tissues. By following a top-down approach to investigate the multiscale organization of pathological bones, quantitative estimates were made in terms of calcium content, nearest neighbor distances of osteocytes, canaliculi diameter, ordering, and D-spacing of the collagen fibrils, and the orientation of intrafibrillar minerals which enable us to observe the fine structural details. We identify and discuss a series of two-dimensional (2D) and 3D imaging techniques that can be used to characterize bone tissue. By doing so we demonstrate that, while 2D imaging techniques provide comparable information from pathological bone tissues, significantly different structural details are observed upon analyzing the pathological bone tissues in 3D. Finally, particular attention is paid to sample preparation for and quantitative processing of data from electron microscopic analysis.     

Fluorescence study of protein immobilization on poly(4-hydroxyphenyl thiophene-3-carboxylate)-coated electrodes

Synthesis of poly(4-hydroxyphenyl thiophene-3-carboxylate) (PHPT) was carried out in acetonitrile(ACN)/TBAClO₄(0.05 M) solvent-electrolyte medium using different working electrodes (glassy carbon and ITO) via potentiodynamic electrolysis. Characterization of the resulting polymer was performed using cyclic voltammetry (CV), scanning electron microscopy (SEM), atomic force microscopy (AFM) and fluorescence microscopy (FS). The polymer exhibits well-defined and reversible redox behavior in an organic solvent. Flourescence microscopy indicates that protein immobilizes better onto the surface of PHPT-modified electrodes than onto those without such modification.     

Evaluation of Dispersion Based Calculations Compared to the Experimental Compressive Strength Results of CNT/6063AI Composites

Nowadays, it is vital to predict strength results of composites in advance of manufacturing process to reduce testing costs; especially in carbon nanotube （CNT） reinforced metal matrix composites. Therefore, compressive mechanical properties of fabricated CNT reinforced aluminum （AI） matrix composites are investigated and compared with the calculation results of dispersion based prediction models. First of all, CNT/6063 AI composites are fabricated by vacuum assisted infiltration of molten 6063 AI alloy into the CNT preform. Then, compressive mechanical properties of these composites are determined. Eventually, model calculations and experimental results are visualized by plotting comparison graphs. As a result, correlation between prediction models and experimental results are established and potential results of difference between these results are discussed.     

Determinacy and Concurrency Issues in Process Engineering

The goal of creating high-quality process systems for real-world applications leads to the need for an engineering approach to process system development. The development of process engineering as a distinct discipline can be greatly facilitated through the development of an engineering framework that supports the rigorous engineering of process systems.Reliability, cost and timeliness are key attributes of quality for engineering artifacts, independent of the specific engineering discipline. As a result, attention to these and other related issues of process system quality during process system design is viewed as necessary if order to achieve desired levels of quality in the resulting process systems.The task system model, a task-based process formalism that can serve as the basis for a process engineering framework, is described. Extensions to this model that are specifically intended to address process system reliability and parallelism are introduced. Process system reliability is addressed through the introduction of methods to ensure determinacy among concurrently executing tasks of a process system that share resources.Process system operating costs and execution timeliness are addressed by maximizing parallelism to the extent that reliability is not compromised.