Search

In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender. An energy-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.

This study was intended to investigate the extent of genetic differentiation in parental lines of rice hybrids and to analyze the genetic basis underlying the fertility phenomenon in distant crosses. Two subsets of rice material (111 entries in total) were used, including 81 doubled-haploid (DH) lines and 30 Indica and Japonica rice varieties or lines (as a control). The DH lines was derived from a heterotic Indica/Japonica cross (Gui630/02428) by anther culture. The materials in the control represent a broad spectrum of the Asian cultivated rice gene pool including landraces, primitive cultivars, historically important cultivars, modern elite cultivars, super rice and parents of superior hybrids. In accordance with the NC II design, 57 out of the DH lines were test-crossed to two important wide compatibility lines: photoperiod-sensitive genetic male sterile (PGMS) line N422s and thermo-sensitive genetic male sterile (TGMS) line Peiai64s. The F1s and their parents, 182 entries in total, were examined for the performance of seven traits in a replicated field trial. All the rice materials was surveyed for polymorphisms using 92 RFLP markers selected from two published molecular marker linkage maps. Genotypes of the F1 hybrids at the molecular-marker loci were deduced from the parental genotypes. The analysis showed that there were two types of genetic differentiation in the two subsets of rice material; that is, qualitative differentiation in the control and quantitative differentiation in the DH lines. In addition, favorable genic interactions (both intra- or inter-locus) contributed to better increase the fertility in hybrids of distant crosses through incorporation of a wide-compatibility line as the female parent. Favorable genic interactions can be applied in hybrid rice breeding programs by selecting parents with an appropriate extent of genetic differentiation.

Oprensning af proteiner er en proces i stadigt stigende vigtiggrad for den bioteknologiske industri. Separering af det ønskede protein af høj værdi fra andre proteiner, produceret at cellen sker oftest ved en kombination af forskellige kromatografiske teknikker. Disse separerer blandinger af proteiner på basis af ladninger, grad af hydrofibicitet eller molekylær størrelse. Tilstrækkelig renhed opnås ofte kun ved kombination af adskillige rensningstrin, hvorfor de samlede omkostninger stiger og produktudbyttet falder. Konventionel fraktionering af proteiner ved brug af ultrafiltreringsmembraner er begrænset til forskelle i størelse af proteinerne, og en rimelig separationsfaktor kan kun opnås når størrelsesforskellen proteinerne imellem er en faktor 10 eller mere. Dette skyldes til dels polarisation af koncentration og tilsmudsning af membranens overflade, hvilket forhindrer en effektiv separation. Anvendelse af et elektrisk felt henover den porøse membran har vist sig en effektiv måde at reducere koncentrationspolarisationen og membrantilsmudsningen. Derudover kan denne teknik også bruges til at separere proteiner med forskellige ladninger, hvilket til en hvis grad overvinder begrænsningerne i størrelsesforskel. I denne afhandlig er undersøgt separation af aminosyrer, bovine serum albumin (BSA) og industrielle enzymer fra Novozymes ved brug af crossflow electro-membrane filtretion (EMF). Hovedformålet med studiet var at undersøge den teknologiske muliggørelse af EMF indenfor industriel enzymfraktionering, såsom fjernelse af sideaktiviteter fra hovedaktivitet. Som proof-of-concept, blev aminosyrer brugt som modelopløsning til at teste muliggørelse af EMF i forbindelse med amfoterisk molekylseparation. En enkelt aminosyre blev brugt til at illustrere effekten af et elektrisk fel på transporten af en ladet aminosyre. Massetransporten can forøges eller mindskes kraftigt når en elektrisk felt virker i samme retning som, eller modsatrettet, den konvektive transport. Vanddeling forårsaget ved grænsende strømdensitet blev observeret ved polaritet +UF– (anode ved membransiden), forårsaget af udtømningen af ioner i permeatsiden.Ved anvendelse af et elektrisk felt i ultrafiltreringen, var det muligt at afkoble transporten imellem det ladede molekyle Glu og det uladede Leu, grundet en enorm mindskelse i transporten af Glu som følge af elektroforetiske kræfter. Separationen kan indstilles ved valg af forskellige kombinationer af strømdensitet og det trans-membrane tryk (TMP). Den største selektivitet (Leu ift. Glu) blev næsten 90 ved 60 A/m2 strømdensitet og 0.3 bar TMP. Effekten af det elektriske felt blev også undersøg og verificeret ved EMF af BSA-opløsning. EMF af BSA med UF og de mere åbne MF-membraner blev undersøgt og sammenligned med konventionel UF of MF i form af flux og gennemtrængning. Det blev fundet, at fluxen og gennemtrængningen kan manipuleres of forudsiges baseret på kendskab til pH og polaritet af det elektriske felt. Membran-protein og protein-protein interaktioner som følge af elektrostatiske kræfter skal dog tages i behold, og bør udnyttes i forbindelse med optimering. Endelig har separationseksperimenter med binære blandinger af lipase (LP) og phospholipase (PLA) vist, at det er muligt at isolere LP (sideaktivitet) fra PLA (hovedaktivitet) ved brug af EMF med MF-membraner, hvilket ikke er muligt med normal MF. Den største selektivitet (LP ift. PLA) blev observeret til ca. 5. Effekterne af fødekoncentration, pH, membrankarakteristika, TMP og elektrisk feltstyrke er ligeledes undersøgt. Det er vist, at separationen, i form af selektivitet og lipaserenhed, afhænger af fødekoncentration, pH og membrankarakteristika. Elektrisk feltstyrke og TMP bidrager i mindre grad til separationen end de øvrige faktorer. Massetransporten af hvert enzym kan vel karakteriseres ved den udvidede Nernst-Planck-teori. En bedre separation blev observeret ved lavere fødekoncentration, højere pH og med en polysulfon-MF-membran. Det kan konkluderes, at EMF succesfuldt har separeret proteiner, som normale tryk-drevne membraner ikke kan opnå. For at opnå en endnu bedre separation er det nødvendigt at antage en holistisk optimeringsprocedure for fremtidigt arbejde. Purification of proteins is an increasingly important process for the biotechnology industry. Separation of the desired high value protein from other proteins produced by the cell is usually attempted using a combination of different chromatographic techniques. These techniques separate mixtures of proteins on the basis of their charge, degree of hydrophobicity, affinity or size. Adequate purity is often not achieved unless several purification steps are combined thereby increasing cost and reducing product yield. Conventional fractionation of proteins using ultrafiltration membranes is limited to the variation in size of the proteins and a reasonable separation factor can be observed only when the size difference is in the order of 10 or more. This is partly caused by concentration polarization and membrane fouling which hinders an effective separation of the proteins. Application of an electric field across the porous membrane has been demonstrated to be an effective way to reduce concentration polarization and membrane fouling. In addition, this technique can also be used to separate the proteins based on difference in charge, which to some extent overcome the limitations of size difference. In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field on the transport of a charged amino acid; the mass transport can be enhanced or decreased enormously when an electric field is applied in the same direction with convective transport or opposite to the direction of convective transport. Water splitting caused by limiting current density situation was observed at polarity +UF- (anode at ultrafiltration membrane side) due to the depletion of ions in the permeate compartment. By applying the electric field in UF filtration, it was possible to uncouple the transport between the charged Glutamic acid (Glu) and neutral Leucine (Leu) due to the fact that mass transport of Glu was enormously decreased because of electrophoretic force and that of Leu was not affected. The separation performance can be tuned by choosing different combinations of current density and TMP. The highest selectivity value (Leu separation from Glu) was achieved at nearly 90 in the condition of 60 A/m2 current density and TMP 0.3bar. The effect of electric field was also investigated and verified with EMF filtration of BSA solution. EMF filtration of BSA both with ultrafitration (UF) membrane and more open microfiltration (MF) membrane was studied and compared with normal UF and MF filtration in terms of flux and transmission. It was found that the flux and BSA transmission can be well manipulated and predicted based on the knowledge of solution pH and the polarity of electric field. However, the membrane-protein and protein-protein interactions caused by electrostatic interactions have to be taken into account and should be considered for optimization purpose. Finally the separation experiments with a binary mixture of Lipase (LP) and Phospholipase (PLA) were performed. Results have shown that separation of LP (side activity) from PLA (main activity) which is not possible to achieve with normal MF has been successfully performed with EMF filtration using MF membrane. The highest selectivity value (LP separation from PLA) of around 5 was obtained when operating with EMF. The effects of feed concentration, solution pH, property of porous membrane TMP and electric field strength have been investigated in the EMF experiments. It has been found that the separation performance in terms of selectivity and Lipase purity in permeate was dependent on the feed concentration, solution pH and membrane properties. The effects of increasing electric field strength and TMP on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane. It can be concluded that EMF has been successfully demonstrated for the separation of enzymes which normal pressure-driven membrane process could not achieve. However, in order to achieve better separation a holistic optimization procedure is needed for future work.

Two multipath schemes have been put forward: primary/backup mode and replication mode. Both schemes have not efficiently combined load balancing and energy awareness in sensor networks. This paper proposes an energy-aware load-balancing delivery scheme. The packets can be transmitted along multiple paths according to decisive energy ratio (DER). It needs not calculate DER periodically and brings fewer overheads. DER with Overload Avoidance (DEROA) is also proposed to avoid heavy traffic on some critical nodes. The simulations demonstrate how well DER will achieve multipath delivery.

Energy distribution is an important issue in sensor networks. Most solutions have not efficiently combined load balancing and energy awareness. This paper firstly proves that the maximum energy consumption will happen around the sink node on the basis of the critical analysis. An efficient energy-aware load-balancing delivery scheme is proposed. It lets the sink node take the responsibility to manage a core set in which the nodes are one hop to the sink. The nodes in the core set will transmit the traffic according to decisive energy ratio (DER) with an efficient energy distribution way. The simulations show the proposed scheme is very efficient and simple to be implemented.