Hermetia illucens, is used as a reducing agent of palm kernel meal (PKM), as well as one of alternative protein sources for aquaculture purposes. Information about biology of H. illucens is absolutely required in mass production. The objectives of these researches were to study the development of H. illucens including the effect of supplementary food to the adult, and nutrient content of the immature stage. The sample of 20 larvae from each 3 replicates were measured and weighed on 0-19th day (larva) and 24th day (pupa) from egg hatching. H. illucens adults were fed by water and honey 5% (v/v). Eggs were collected and counted. Nutrient content of immature stage: 5, 10, 15, 20 days old (larvae), and 25 days old (prepupae) reared on PKM were analyzed proximately. Dry matter was determined by weight loss on drying at 105 oC during overnight. Crude protein was determined by Kjeldahl procedure (N x 6.25), crude fat by soxhlet (ether extract), crude ash by determining the residue after heating at 550 oC for 4–5 h. Data were analyzed descriptively by average from triplicate. The development of H. illucens was shorter than those in previous studies as the differences of abiotical factor. PKM was a suitable medium for development. It was better, however, to fed the adult with honey since it could enhance the fecundity. The young larva certainly contained the best quality of nutrition. To meet the quantity of mass production, however, the use of the elder larva (bigger) was suggested.
Several methods were used to investigate the possibility of preparing inclusion complexes between amylose and polytetrahydrofurans (PTHF) via direct mixing. Potato amylose (M(v) ∼ 200 kg/mol) and synthetic amylose (M(n) 42 kg/mol) were complexed with PTHF having different molecular weights (M(n) between 650 and 2900 g/mol) to study the effect of the length of the host and the guest molecules on the complexation. The resulted products were studied by differential scanning calorimetry (DSC) that showed a characteristic melting peak in the range of 120-140 °C. Emulsification of both amylose and polytetrahydrofuran improved the complexation. The largest amount of complexes was obtained with shorter PTHF chains, which also resulted in less amylose retrogradation. Furthermore, PTHF chains with similar molecular weight but different end groups were used. Amine terminated PTHF formed a higher amount of complexes compared to the hydroxyl terminated PTHF. However, no amylose complexes were formed using benzoyl terminated PTHF with low molecular weight. This is due to the bulky group of benzoyl, which indicates that the mechanism of the complexation between amylose and PTHF occurs via insertion rather than wrapping. In addition, X-ray diffraction (XRD) analysis showed that the included PTHFs induced the formation of the so-called V-amylose with six glucose residues per helix turn. Some additional diffraction peaks indicate that the induced V(6)-amylose is probably an intermediate or the mixtures between V(6I)- and V(6II)-amylose.
Amylose and polytetrahydrofuran (PTHF) are mixed in an aqueous solution to form inclusion complexes. DSC shows that immediate mixing results in complexes having lower melting temperatures compared with complexes prepared with longer mixing times. The washed complexes melt at higher temperatures compared with the corresponding unwashed complexes. XRD indicates that amylose-PTHF complexes diffract similar to amylose-fatty acids complexes (V6I -amylose helices), with additional diffractions correlating with amylose-alcohol complexes (V6II -amylose helices). This suggests that the structure of amylose-PTHF complexes is an intermediate or a mixture between V6I - and V6II -amylose. This shows that, besides residing inside the amylose helices, some PTHF chains are located in between the amylose helices.
Highly crystalline amylose-polytetrahydrofuran (PTHF) complexes can be obtained by employing organic solvents as washing agents after complex formation. The X-ray diffraction (XRD) of the washed complexes appear sharp at 12.9°-13.2° and 19.6°-20.1°, clear signs of the presence of V6I -amylose. Other diffraction peaks correlate with V6II -amylose, which indicates that the complexed amylose helices are in the form of an intermediate or a mixture of V6I - and V6II -amylose. SEM imaging reveals that the amylose-PTHF complexes crystallize in the form of lamellae, which aggregate in a round shape on top of one another with a diameter around 4-8 μm. Some lamellas aggregate as flower-like or flat-surface spherulitic crystals. There is a visible matrix in between the aggregated lamellas which shows that a part of the amylose-PTHF complexes is amorphous.
Using atom transfer radical polymerization (ATRP), poly(tert-butyl methacrylate-b-styrene-b-4vinylpyridine) or PtBMA-b-PS-b-P4VP linear triblock copolymers were synthesized. Different homopolymer and diblock copolymer macroinitiators were used for different block copolymerizations. For a selected triblock copolymer the self-assembly was studied with transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and thermal analysis. Indications were found for a core-shell hexagonal ordering of coaxial cylinders with P4VP cylinders separated from the PtBMA matrix phase by a PS shell layer. To further support this, the interaction parameter between styrene and tBMA was investigated by a random copolymer blend miscibility study on blends of P(S-co-tBMA) random copolymers with PS and found to satisfy 0.08 < χ S,tBMA < 0.10.
Amylose inclusion complexes are prepared by complexation of synthetic amylose having a covalently attached PTHF block (PTHF-b-amylose) with guest polytetrahydrofuran of molecular weights of 650 and 1000 g · mol(-1) (PTHF650 and PTHF1000). Differential Scanning Calorimetry (DSC) analysis of the products shows a characteristic melting peak of the complexes at 140 °C. Compared to PTHF650, the PTHF1000 displays lower complexing ability with PTHF-b-amylose which is indicated by visible amylose retrogradation. The possible structures of the resulting products are estimated from Thermo Gravimetric Analysis (TGA) which reveals differences between PTHF-b-amylose and the corresponding complexes. In addition, X-Ray Diffraction (XRD) analysis demonstrates that the resulting structures of the complexes consist of 6-fold V-amylose helices. The results are confirmed further with Small Angle X-Ray Scattering (SAXS) diffractions which show that formation of inclusion complexes increases the crystalline size and regularity of the complex. There is a strong indication that the covalently attached PTHF block also induces the formation of V-amylose by residing in between the amylose blocks. In this case, the resulting structure of the complex is likely affected by both the complexation between amylose block and the added PTHF and by the in situ self-assembly of the block copolymers.
Back Cover: Amylose and polytetrahydrofuran have the ability to form highly crystalline inclusion complexes which show interesting behavior in organic solvents. http://doi.wiley.com/10.1002/mabi.201300174, Katja Loos and colleagues show how the selfassembly of the complexes as lamellae further emphasizes their potential in supramolecular chemistry. Cover design by Alessio Marcozzi.
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