Secondary Aggregation Research Articles

Engineering Characteristics and Stabilization Performance of Aggregate Quarry By-Products From Different Sources and Crushing Stages

Quarry by-products (QB), usually less than 1/4 in. (6 mm) in size, are the residual deposits from the production of required grades of aggregate. This paper provides findings of a detailed laboratory study with the objective of characterizing the engineering properties of QB materials produced in the primary, secondary, and tertiary aggregate production stages from four different quarries operating in Illinois. Property tests were conducted for determining aggregate gradation, morphological shape characteristics, compaction properties (moisture-density), chemical composition and strength properties of QB samples. Since the unconfined compressive strength for QB materials is relatively low, chemical admixture stabilizers such as Portland cement and Class C fly ash were used to improve the strength properties. This study aims at evaluating properties governing the untreated and stabilized strength of QBs such as source variation, compacted density, chemical composition, gradation, particle shape and angularity, as well as the uniformity of distribution and the effectiveness of stabilizer. QB samples treated with 2% cement or 10% Class C fly ash by dry weight were found to be 10 to 30 times stronger than the virgin QB samples. Such significant increases in the strength of stabilized QB materials observed may indicate suitability of QBs for sustainable pavement applications.

Nutrient and pesticide remediation using a two-stage bioreactor-adsorptive system under two hydraulic retention times

Nutrients and pesticides in agricultural runoff contribute to the degradation of water resources. Nitrates and phosphates can be remediated through the use of treatment systems such as woodchip bioreactors and adsorbent aggregate filters; however, concerns remain over potential effects of pesticides on nutrient removal efficiency in these systems. To test this, we designed laboratory-scale woodchip bioreactors equipped with secondary adsorbent aggregate filters and investigated the capacity of these systems to remediate nutrients when operated under two hydraulic retention times (HRT) and in the presence of commonly used pesticides. The woodchip bioreactors effectively removed over 99% of nitrate per day when operated under a 72 h hydraulic retention time, with the secondary expanded shale aggregate filters consistently reducing phosphate concentrations by 80–87%. Treatment efficacy of both systems was maintained in the presence of the insecticide chlorpyrifos. Reducing HRT in the bioreactors to 21 min decreased nitrate removal efficiency; however, the insecticides bifenthrin, chlorpyrifos, and the herbicide oxyfluorfen were reduced by 76%, 63%, and 31%, respectively. Cultivation approaches led to the isolation of 45 different species from the woodchip bioreactors operated under a 21 min HRT, with Bacillus species being the most prevalent throughout the treatment. By contrast, pesticide application decreased the number and diversity of Bacillus isolates and enriched for Pseudomonas and Exiguobacterium species. Woodchip bioreactors and adsorbent aggregate filters provide effective treatment platforms to remediate agrochemicals, where they maintain treatment efficacy in the presence of pesticides and can be modulated through HRT management to achieve environmental and operational water quality goals.

Foreign Shareholdings Impact on Banks Efficiency and Moderating Role of Corporate Governance

The research investigate the impact of foreign shareholding originated from developed and developing countries on the efficiency of acquired local banks in Indonesia during 2007-2017 by including Corporate Governance as a moderating variable. Methodology: Using the secondary aggregate data of 29 commercial banks acquired by foreign shareholders, a panel regression model using econometrics methods of GLS, and DEA were applied to examine the effects of percentage of foreign shareholdings on efficiency of the acquired local banks. The main findings; First, percentage of foreign shareholdings positively affecting efficiency of acquired local banks only if the foreign shareholders is originated from developed countries. Second, the level of economic advancement of the country of origin of foreign shareholders has significant effects on the efficiency of the acquired local banks. Third, the increase in the size of the Board of Directors tends to decrease the efficiency of the acquired local banks and fourth, the presence of Foreign Director has a positive moderating effect on strengthening the effect of percentage of foreign shareholdings on the efficiency of the acquired local banks. Overall, the originality of this studies is that the percentage of foreign shareholdings and its country of origin are two combined factors that cannot be separated in affecting the level of efficiency of its acquired local bank and the fact of significant positive moderating effect of Foreign Director. As policy consideration, monetary authority need to perform strict due diligence on prospective foreign shareholders specifically originated from developing countries, advise banks to maintain the existence of Foreign Director and to encourage small local banks to be merged prior to the acquisition by foreign shareholders.

Quantification of micropolarity and microviscosity of aggregation and salt-induced gelation of sodium deoxycholate (NaDC) using Nile red fluorescence.

This study reports the utility of the hydrophobic probe Nile Red (NR) to understand the concentration induced microenvironmental changes of sodium deoxycholate (NaDC) bile salt from the premicellar to postmicellar range. The spectroscopic properties like absorbance value, fluorescence intensity and fluorescence lifetime of NR are significantly sensitive towards different states of aggregation of NaDC bile salt. The critical aggregation concentrations of different states (dimer to primary micellar aggregates (1.0 mM), secondary micellar aggregates (7.0 mM), and higher micellar aggregates (14 mM)) have been determined from the absorbance value and fluorescence intensity measurements. The ET(30) polarity parameter values suggest a considerable decrease in the micropolarity with an increase in NaDC concentrations. Furthermore, the spectroscopic properties of NR are also sensitive towards the NaCl induced gelation process of NaDC bile salt. Changes in the micropolarity and microviscosity of the NaDC + NaCl mixed system have been estimated using the emission maximum value (cm-1) and fluorescence lifetime values of NR with an increase in the NaCl concentration. Microviscosity of the medium increases from ∼19 mPa s to ∼26 mPa s from the sol phase to the gel phase. Temperature dependence of both size and phase changes of the NaDC + NaCl (30 mM + 1 M) gel network has been studied using differential scanning calorimetry and dynamic light scattering studies. Temperature induced polarity and microviscosity changes of the NaDC + NaCl (30 mM + 1 M) gel network have also been studied using the fluorescence properties of NR.

State of a sustainable drainage system at end-of-life: assessment of potential water pollution by leached metals from recycled pervious pavement materials when used as secondary aggregate.

Sustainable drainage systems (SuDS) have emerged as an effective and attractive approach for stormwater management, prevention of water pollution and flood control due to its sustainable, environmentally friendly and cost-effective approaches. One of the SuDS devices widely used to infiltrate, store and treat surface runoff which allows it to recharge groundwater is the pervious paving systems (PPS). Previous studies have demonstrated relatively high pollution removal efficiencies typically ranging from 98.7% for total hydrocarbons to 89% of COD. Although a small number of the studies have assessed the performance characteristics of the PPS system in long-established installations in terms of retention of pollutants, hydrological features, biodegradation of pollutants etc., none has assessed the risk of potential groundwater and soil pollution by pollutants such as metals retained in the PPS materials either as a disposed waste material (in the case of used geotextiles) or during re-use as secondary aggregates. Thus, this study evaluated potential risks associated with the decommissioning and beneficial use of wastes produced during the disassembly of a PPS. The authors believe that this was the first PPS to be addressed in this way. The method involved the determination of leachable concentrations of 14 metals in the PPS samples made up of extracts from the model profile which included the geotextile fibre (G), dust alone (D), aggregates and dust (AD), aggregates alone (AA) and pavement blocks (P) which were analysed and compared with two different groups of regulatory threshold limits. The results showed that the measured concentrations of all the metals were below the appropriate threshold values for irrigation purposes as specified by FAO and USEPA. Furthermore, results all indicated that the dismantled materials were all below EU LFD WAC limits for inert waste, indicating relative ease of disposal and suitability for use as recycled aggregate. This, admittedly limited data, indicates that recycling of aggregates from demolition wastes arising from end of life PPS would not be limited by the potential leaching of heavy metals, including re-use within another PPS. This would minimise dependence on virgin aggregates and hence reduce rate of exploitation of natural resources and improve sustainability score card of SuDS.

The Role of Post-translational Modifications on the Energy Landscape of Huntingtin N-Terminus.

Huntington disease is a neurodegenerative disease characterized by a polymorphic tract of polyglutamine repeats in exon 1 of the huntingtin protein, which is thought to be responsible for protein aggregation and neuronal death. The polyglutamine tract is preceded by a 17-residue sequence that is intrinsically disordered. This region is subject to phosphorylation, acetylation and other post-translational modifications in vivo, which modulate its secondary structure, aggregation and, subcellular localization. We used Molecular Dynamics simulations with a novel Hamiltonian-replica-exchange-based enhanced sampling method, SWISH, and an optimal combination of water and protein force fields to study the effects of phosphorylation and acetylation as well as cross-talk between these modifications on the huntingtin N-terminus. The simulations, validated by circular dichroism, were used to formulate a mechanism by which the modifications influence helical conformations. Our findings have implications for understanding the structural basis underlying the effect of PTMs in the aggregation and cellular properties of huntingtin.

Municipal solid waste incineration bottom ash as alkali-activated cement precursor depending on particle size

Abstract Bottom Ash (BA) is the main by-product of municipal solid waste incineration (MSWI). It is stabilised outdoors to obtain weathered bottom ash (WBA) whose main application is in the construction sector as a secondary aggregate for road sub-base. Here, the aim of this work is to advance the study of the potential use of WBA as a precursor in the synthesis of new alkali-activated cements (AACs). An exhaustive physicochemical characterisation (X-ray fluorescence, X-ray diffraction, Fourier-transform infrared spectroscopy, inductively coupled plasma – optical emission spectroscopy, and Inductively coupled plasma – mass spectroscopy) of WBA was provided depending on its particle size (

Effect of gemini surfactants on binding interactions of Coumarin 485 with calf thymus deoxyribonucleic acid in presence of nanotubes of β-cyclodextrin

Present study is focused on the binding of a dye, Coumarin 485 (C-485) with Calf thymus deoxyribonucleic acid (ctDNA), explored using the spectroscopic tools such as UV–visible absorption, steady-state fluorescence and fluorescence anisotropy, and time-resolved fluorescence spectroscopy and dynamic light scattering measurements. The hyperchromic shifts in UV–visible absorption and fluorescence bands depict that the C-485 binds with the ctDNA. Absorption spectrum of C-485 in presence of ctDNA, ethidium bromide displacement assay and iodide ion quenching experiment confirm that C-485 binds with ctDNA through the groove binding mode. β-Cyclodextrin (β-CD) molecules (host) in presence of C-485 (guest) form the nanotubes and secondary aggregates of nanotubes which has been explored as the carriers of C-485 for ctDNA. The binding efficiency of C-485 with β-CD is reduced in presence of ctDNA. Gemini surfactants, m-4-m (m = 12, 14 and 16) induce the release of C-485 from the cavities of nanotubes of β-CD. After getting released from the cavities, C-485 molecules bind with ctDNA in the form of inclusion complexes with β-CD/un-complexed state at a low concentration range of a gemini surfactant. A gemini surfactant with comparatively longer hydrocarbon tails pushes the guest molecules (C-485) out of the nanotubular cavities of β-CD more efficiently due to greater extent of hydrophobic interactions between the cavities and tails.

Part 2: Physicochemical characterization of bevacizumab in 2 mg/mL antibody solutions as used in human i.v. administration: Comparison of originator with a biosimilar candidate

The physicochemical properties of Avastin® manufactured in the USA (Originator USA) and in Europe (Originator EU) and ABX-BEV, a bevacizumab biosimilar drug product candidate produced by Apobiologix Inc., were characterized at a clinically relevant concentration of 2 mg/mL following dilution of the 25 mg/mL drug products with 0.9% NaCl. Measurements using 14 orthogonal analytical methods performed within 5 h after dilution showed good similarity of the three antibodies as regards secondary structure, conformation, aggregation properties, subvisible and visible particles. No significant protein aggregation was observed within 5 h at 24 °C in the 2 mg/mL bevacizumab solutions. The same solutions that were measured within 5 h after dilution were analyzed again after 24 h overnight refrigeration at 2–8 °C: all 2 mg/mL bevacizumab solutions showed an increase in the number and sizes of aggregates, especially the particles larger than 10 μm and 25 μm. The data show the very good similarity in the physicochemical properties of ABX-BEV with Originators USA and EU at a clinically relevant concentration.

Transparent, mechanically strong, thermally insulating cross-linked silica aerogels for energy-efficient windows

Silica aerogels are transparent and excellent thermal insulators; however, application in energy-efficient windows has been elusive. The main reason is fragility that renders handling and processing extremely difficult. One way to overcome the fragility issue of silica aerogels is via cross-linking technology, in which a polymer is applied conformally over their entire skeletal framework. Extremely strong materials may be obtained by that approach; however, the penalty is loss of transparency. This study was designed to reach a compromise among those competing requirements. Aerogels based on co-gelation of tetramethylorthosilicate (TMOS) and 3-aminopropyltriethoxysilane (APTES) were prepared and were cross-linked with a triisocyanate (Desmodur N3200A). The two independent variables, the total silane concentration in the sol and the concentration of the monomer in the cross-linking bath, were varied according to a full-factorial model. The nanostructure was characterized with SEM and SAXS. The porous structure with N2 sorption. Properties of interest with respect to the intended application were the thermal conductivity, the elastic modulus, and the haze. The latter has two components, from the bulk and the surface. Cross-linking places the polymer inside secondary aggregates that behave as core–shell particles with increased scattering, due to refractive index mismatch. Surface haze can be minimized by molding with clean glass plates and careful handling. Guided by our statistical model, we demonstrate optimal samples with bulk densities in the range of 0.25–0.33 g cm−3, porosities in the range of 76–83% v/v, bulk haze around 10%, Young’s modulus in the range of 30–70 MPa, and thermal conductivities in the range of 18–22 mW m−1 K−1. Those samples were strong enough to be machined with conventional tools (band saws, diamond cutters), they displayed sufficient clarity, and their thermal conductivity was lower than that of still air.

Sequence Versus Composition: What Prescribes IDP Biophysical Properties?

Intrinsically disordered proteins (IDPs) represent a distinct class of proteins and are distinguished from globular proteins by conformational plasticity, high evolvability and a broad functional repertoire. Some of their properties are reminiscent of early proteins, but their abundance in eukaryotes, functional properties and compositional bias suggest that IDPs appeared at later evolutionary stages. The spectrum of IDP properties and their determinants are still not well defined. This study compares rudimentary physicochemical properties of IDPs and globular proteins using bioinformatic analysis on the level of their native sequences and random sequence permutations, addressing the contributions of composition versus sequence as determinants of the properties. IDPs have, on average, lower predicted secondary structure contents and aggregation propensities and biased amino acid compositions. However, our study shows that IDPs exhibit a broad range of these properties. Induced fold IDPs exhibit very similar compositions and secondary structure/aggregation propensities to globular proteins, and can be distinguished from unfoldable IDPs based on analysis of these sequence properties. While amino acid composition seems to be a major determinant of aggregation and secondary structure propensities, sequence randomization does not result in dramatic changes to these properties, but for both IDPs and globular proteins seems to fine-tune the tradeoff between folding and aggregation.

Fenton cleaning strategy for ceramic membrane fouling in wastewater treatment

Membrane fouling is an obstacle impeding the wide applications of ceramic membranes and organics are responsible for most of the membrane fouling issues in wastewater treatment. In this study, Fenton cleaning strategy was firstly proposed to clean ceramic membrane fouling in wastewater treatment. Fe2+ efficiently catalyzed fouling cleaning with H2O2 (1.5%) to recover the filterability of ceramic membrane. The maximum ∆TMP recovery (over 99%) was achieved at an optimal Fe2+ dosage of 124 mg/L after 6 hr of immersion cleaning. The total residual membrane fouling resistance decreased gradually from this optimum value as the Fe2+ dosage increased above 124 mg/L. The residual hydraulically reversible fouling resistance accounted for most of the membrane fouling and was basically removed (≤3.0 × 109 m−1) when Fe2+ dosages higher than 124 mg/L were used. The foulants responsible for the formation of a residual hydraulically reversible fouling layer (DOC (dissolved organic carbon), proteins, polysaccharides, EEM (fluorescence excitation-emission matrix spectra), SS (suspended solids), and VSS (volatile suspended solids)) were gradually removed as the Fe2+ dosage increased. These residual organic foulants were degraded from biopolymers (10–200 kDa) to low molecular weight substances (0.1–1 kDa), and the particle size of these residual foulants decreased significantly as a result. The strong oxidation power of hydrogen peroxide/hydroxy radicals towards organic foulants was enhanced by Fe2+. Fe2+ played a significant role in the removal of hydraulically reversible fouling and irreversible fouling from the ceramic membrane. However, Fe2+ (≥124 mg/L) increased the likelihood of forming secondary iron-organics aggregates.

The Ni-rich nanostructured solid solutions of Ni1−xMx (M = Cd, Co and Cu)

The nanostructured solid solutions (NSSes) of Ni–Cd (Cu, Co) with the FCC lattice were obtained by a simple chemical method. The NSSes consist of nanocrystallites (10–25 nm) which form the primary aggregates (40–80 nm) composing the secondary aggregates (100–500 nm). The Ni–Cd and Ni–Cu nanocrystallites were shown to be anisometric, which is unusual for the FCC lattice. The Ni–Cd aggregates contain the structural units consisted of the stratification of the nano-thick crystallites by the (111) and (200) faces with a wide surface in common and spatial orientation. The spatial heterogeneity of compounds for the aggregates of Ni–Cd and Ni–Cu can be explained because of the differences in the nanocrystal chemical compositions. The main reason of it is in the differences in the redox potentials of the components of the bimetallic NSSes obtained by chemical reactions. The surface of the primary aggregates contains H2O, O2, CO2 and, probably, hydroxide and oxide as nano-islets in a layer whose thickness is approximately 1–3 nm. These inclusions can be desorbed or decomposed at 100 °С–140 °С, 120 °С–220 °С and 300 °С–400 °С accordingly. The obtained non-equilibrium solid solutions (up to 5% of Cd or Cu) have saturation magnetization in low magnetic fields also decrease in this magnetization and coercivity (80–260 Oe at 300 K).

Formation, stability, and sensory characteristics of a lentil-based milk substitute as affected by homogenisation and pasteurisation

This study aimed to investigate the suitability of lentil protein and emulsions thereof for the formulation of a milk substitute. The effect of high-pressure homogenisation and heat treatments on functional and physico-chemical properties of lentil protein solutions (3.3% w/w) and the emulsions, containing fat contents similar to commercial cow’s milk, was studied. Dynamic high-pressure treatments of 180 and 900 bar greatly affected physical and structural properties of the lentil proteins: the particle size was reduced by 100-fold to 129.00 nm for samples homogenised at 900 bar, leading to an almost complete solubilisation. Surface properties of lentil protein changed, as shown in an increase of hydrophobicity and decrease of free sulfhydryl groups, while changes in secondary structure and aggregation did not develop. Little impact was observed of the heat-treatment at 65 or 85 °C, however, colour changed from a faint pink hue to be more white in appearance. The obtained emulsions exhibited good colloidal stability at both homogenisation pressures, while overall product quality was best when treated at 900 bar. Sensory analyses showed the formulated lentil-based milk substitute had textural and organoleptic profiles comparable to commercial plant-based milk substitutes, including soya-based products. Lentil protein isolates showed great potential to be used formulating milk substitutes with a high-protein content, similar to cow’s milk.

Characteristics of Peel Off Gel Mask From Seaweed (Eucheuma cottonii) Porridge

The aim of this study was to determine the best concentration of E. cottonii seaweed porridge in the formulation of peel off gel masks. The main materials used in this study were <em>E. cottonii</em> and other basic substances of peel off gel mask. The analytical methods used were the total microbial and antioxidant test on the E. cottonii slurry preparation. Mask preparations were analyzed for physical stability, pH, duration of preparation, drying, viscosity and homogeneity. The experimental design used was a Completely Randomized with four treatments by adding <em>E.cottonii</em> porridge 0%, 10%, 15% and 20% respectively with two replications.The results showed that the best peel off gel mask was formulation with the addition 20% of E.cottonii. Microbes were not found in <em>E. cottonii</em> porridge. The antioxidant activity of <em>E. cottonii</em> porridge had IC50 value of 137.35±0.35 μg / mL. Consumer acceptance of products through sensory testing in the category of likes. The peel off gel mask has good physical stability, proven by no changes in color, odor as well as gel texture. The pH value of the preparation of peel off gel mask is in line with SNI and pH balance of normal human skin. The best viscosity value of peel off gel mask is 14,003 cps. The time needed for the mask to dry for an average of 25 minutes and homogeneity is characterized by the absence of secondary particle aggregation.

Moisture Susceptibility of Open-Graded Friction Course Mixes with EAF Steel Slag and Modified Binders

Abstract Open-graded friction course (OGFC) mixtures are sensitive to the moisture damage because of their high air void content and longer exposure to water. In the present study, moisture susceptibility characteristics of OGFC mixes in terms of tensile strength characteristics, aggregate-binder bond strength, and the raveling potential of OGFC mixtures were studied. The experimental design for this study included OGFC mixes with two different types of aggregates (natural aggregates as a main source and electric arc furnace (EAF) steel slag as a secondary source), two different types of modified binders (polymer-modified bituminous binder and crumb rubber–modified bituminous binder), and one cellulose fiber as an additive. OGFC mixes were designed with five different percentages (0, 25, 50, 75, and 100 %) of secondary aggregates as a partial replacement of main aggregates. OGFC mixes were then evaluated for moisture susceptibility through four different test methods, viz. the indirect tensile strength (ITS) or tensile strength ratio (TSR) method, wet abrasion loss (WAL) method, static immersion test method, and modified boiling test method. OGFC mixes with EAF steel slag showed higher ITS values under both dry and wet conditions compared with the control mixes with natural aggregates alone. Steel slag content, binder type, and freeze-thaw cycles had statistically significant effects on the ITS, TSR, and WAL values. Modified boiling test results showed a good correlation with the modified Lottman and WAL test results.

Binding Interaction of Gemini Surfactants with Nanotubes of β‐Cyclodextrin and Controlled Release of Guest Molecules: Effect of Spacer Chain Length and Concentration of Surfactants

AbstractThe formation of guest molecule (Coumarin 485, C‐485) induced nanotubes by β‐cyclodextrin (β‐CD) and their interactions with cationic gemini surfactants (12‐n‐12, where n=3, 6, and 12) have been explored by means of UV‐visible absorption, steady‐state fluorescence and fluorescence anisotropy, time‐resolved fluorescence and fluorescence anisotropy, and dynamic light scattering (DLS) measurements. β‐CD at its high concentration form extended nanotubes and secondary aggregates of nanotubes. A gemini surfactant has a significant role in binding interactions between C‐485 and nanotubes of β‐CD. In a low concentration range, surfactant molecules are co‐associated with the guest molecules, C‐485, however, at high concentrations, they are capable of pushing C‐485 out of the nanotubular cavities. A gemini molecule with a comparatively longer spacer chain is more efficient in removing the guest molecules out of the nanotubular cavities. Also, the rate of release of guest molecules increases with increasing concentration of surfactants. Release of guest molecules from the nanotubes can be tuned by changing the spacer chain length and concentration of gemini surfactants. Guest molecules after coming out of the nanotubular cavities, get solubilized in the micelles formed by surfactant molecules in the solution. The results of the present work suggest potential application in the development of promising drug delivery systems.

Structural characteristics of mPEG-PDLLA and their effects on micelle stability

The correlation between polymer microstructure of mPEG-PDLLA and secondary aggregation of its micelle was studied. Close examination of 1H NMR spectra revealed that the methine moieties, -CH(CH3)-, of mPEG-PDLLA polymer well represented its microstructure. To elucidate the physicochemical characteristics of various microstructures, we have developed an index, called L-ratio, to indicate the relative content of heterotactic component within the polymer. Storage stability of micelles from six polymers with different L-ratios (L-ratio ranging from 28 to 33%) was studied at 30 °C and 50 °C, and changes in average particle size were monitored to evaluate their secondary aggregation. We have found that polymers with high L-ratio takes longer time to secondary aggregation of polymeric micelles to occur. The findings should provide insightful guidance in the development of polymeric micelles.

Effects of formulation development methods on the stability of model protein pharmaceuticals embedded in solid lipid matrices

This study was conducted to investigate the influence of formulation development methods on the stability (secondary structure, aggregation, and biological activity) of protein drugs embedded in lipid matrices. Catalase, horseradish peroxidase, and α-chymotrypsin were employed as model proteins, while Precirol® AT05 (glyceryl palmitostearate) was used as lipid matrix. Protein-loaded lipid matrices were prepared using melting and mixing and wet granulation methods. Attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy, size exclusion chromatography (SEC) and biological activity analyses were performed. ATR FT-IR analysis indicated significant interference of the lipid with the protein amide-I band, which was eliminated using spectral subtraction. Wet granulation method induced more changes in protein secondary structure compared to melting and mixing method. SEC analysis gave evidence of protein aggregation for catalase upon adopting the wet granulation method. The biological activity of catalase was found to reduce significantly than other two proteins upon using wet granulation method, which might be ascribed to both secondary structure alterations and the formation of aggregates. Horseradish peroxidase and α-chymotrypsin did not form any soluble aggregates. In conclusion, melting and mixing method emerged as a better incorporation method compared to wet granulation because of better stability shown by the formulated proteins.

Versatile DNA folding structures organized by cationic block copolymers

DNA folding induced by polyion complexion with cationic polyelectrolytes (or catiomers) is attracting remarkable attention in the context of nucleosome formation during genome packaging and gene vector preparation. The application of block catiomers, in contrast to homocatiomers, is attractive because the spontaneously formed polyplex micellar structure can suppress the occurrence of secondary aggregation, allowing the folding of a single DNA molecule. Here, DNA is folded to form several higher-order structures, including rod-shaped, globular, and ring-shaped (toroid) structures. This review discusses the origin of this versatile higher-order structure formation by addressing the conditions and potential mechanisms underlying when and how DNA is organized into these structures upon complexation with block catiomers. DNA undergoes large volume transition to organize several higher-order structures, including globular, rod-shaped, and ring-shaped (toroid) structures by polyion complexation with block copolymer comprising hydrophilic segment and polycations. This review discusses the origin of this versatile higher-order structure formation. The knowledge of underlying physical mechanisms might ultimately improve our understanding of the formation of hierarchically ordered structures in the nucleosomes and the operating principles governing how DNA functionality emerges, and also provide a solid strategy to prepare structured nonviral gene vectors.