Integration of order picking and vehicle routing in a B2C e-commerce context

E-commerce sales are increasing every year and customers who buy goods on the Internet have high service level expectations. In order to meet these expectations, a company’s logistics operations need to be performed carefully. Optimizing only internal warehouse processes will often lead to suboptimal solutions. The interrelationship between the order picking process and the delivery process should not be ignored. Therefore, in this study, an order picking problem and a vehicle routing problem with time windows and release dates are solved simultaneously using a single optimization framework. To the best of our knowledge, it is the first time that an order picking problem and a vehicle routing problem are integrated. A mixed integer linear programming formulation for this integrated order picking-vehicle routing problem (OP-VRP) is provided. The integrated OP-VRP is solved for small instances and the results are compared to these of an uncoordinated approach. Computational experiments show that integration can lead to cost savings of 14% on average. Furthermore, higher service levels can be offered by allowing customers to request their orders later and still get delivered within the same time windows.     

Metabolic control of the cell cycle

Cell division is a metabolically demanding process, requiring the production of large amounts of energy and biomass. Not surprisingly therefore, a cell''s decision to initiate division is co-determined by its metabolic status and the availability of nutrients. Emerging evidence reveals that metabolism is not only undergoing substantial changes during the cell cycle, but it is becoming equally clear that metabolism regulates cell cycle progression. Here, we overview the emerging role of those metabolic pathways that have been best characterized to change during or influence cell cycle progression. We then studied how Notch signaling, a key angiogenic pathway that inhibits endothelial cell (EC) proliferation, controls EC metabolism (glycolysis) during the cell cycle.     

The c-Ha-ras oncogene induces increased expression of beta-galactoside alpha-2, 6-sialyltransferase in rat fibroblast (FR3T3) cells.

Alteration in cell surface carbohydrates, and in particular cell surface sialylation, have been known to occur during oncogenic transformation. To examine the basis for such changes, we have transformed the rat fibroblast cell line FR3T3 with the oncogenes c-Ha-ras EJ, v-mycOK10, v-src, polyoma virus middle T or the transforming bovine papilloma virus 1 (BPV1), and measured the sialytransferase activities of cellular lysates. We found that, in contrast to all other oncogenes examined, c-Ha-ras induced a striking increase in beta-galactoside alpha-2,6-sialytransferase (Gal alpha-2,6-ST) activity in FR3T3 cells. This increase in Gal alpha-2,6-ST activity resulted in the increased expression of cell surface alpha-2,6-linked sialic acid on cell surface glycoconjugates, as determined by cell staining with fluorescein-labelled Sambucus nigra agglutinin. Immunoprecipitation and immunofluorescence experiments revealed that the increase in Gal alpha-2,6-ST activity was due to an elevation of expression of the enzyme. Moreover, Northern analysis suggested that the increased expression of this enzyme was the result of an increase in the steady-state mRNA level of the Gal alpha-2,6-ST gene. These results support the notion that alterations seen in cell surface glycoconjugates during oncogenic transformation can be the result of altered expression of glycosyltransferases.     

Structural and functional analysis of the fixLJ genes of Rhizobium leguminosarum biovar phaseoli CNPAF512

The fixLJ genes of Rhizobium leguminosarum biovar phaseoli CNPAF512 were identified by DNA hybridization of a genomic library with an internal fragment of the Rhizobium meliloti fixJ gene. The nucleotide sequence was determined and the corresponding amino acid sequence was aligned with the amino acid sequences of the FixL proteins of R. meliloti, Bradyrhizobium japonicum and Azorhizobium caulinodans. While the FixJ protein and the carboxy-terminal part of the FixL protein are highly homologous to the other FixL and FixJ proteins, the homology in the central heme-binding, oxygen-sensing domain and in the amino-terminal domain of FixL is very low. The R. leguminosarum bv. phaseoli FixL protein does not contain the heme-binding motif defined for the previously described FixL proteins. R. leguminosarum bv. phaseoli fixLJ and fixJ mutants were constructed. These mutants can still fix nitrogen, albeit at a reduced level. Expression analysis of nifA-gusA and nifH-gusA fusions in the constructed mutants revealed that the R. leguminosarum bv. phaseoli fixLJ genes are involved in microaerobic nifH expression but not in nifA expression.     

Molecular cloning and characterization of a high DP fructan: fructan 1-fructosyl transferase from Viguiera discolor (Asteraceae) and its heterologous expression in Pichia pastoris

Inulin-type fructans are stored in the tuberous roots of the Brazilian cerrado plant Viguiera discolor Baker (Asteraceae). In Cynara scolymus (artichoke) and Echinops ritro (globe thistle), the fructans have a considerably higher degree of polymerization (DP) than in Cichorium intybus (chicory) and Helianthus tuberosus (Jerusalem artichoke). It was shown before that the higher DP in some species can be attributed to the properties of their fructan: fructan 1-fructosyl transferases (1-FFTs; EC 2.4.1.100), enzymes responsible for chain elongation. Here, we describe the cloning of a high DP (hDP) 1-FFT cDNA from V. discolor and its heterologous expression in Pichia pastoris . Starting from 1-kestose and Neosugar P (a mixture of oligo-inulins from microbial origin) as substrates, the recombinant enzyme produces a typical hDP inulin profile in vitro, closely resembling the one observed in vivo. The enzyme shows no invertase activity and sucrose: sucrose 1-fructosyl transferase (1-SST; EC 2.4.1.99) activity in vitro. Pattern evolution during incubation suggests that inulins with DP ≥ 6 are much better substrates than sucrose or lower DP oligo-fructans. Because hDP inulin-type fructans show superior properties for specific food and non-food applications, the hDP 1-FFT gene from V. discolor has potential for the production of hDP inulin in vitro or in transgenic crops.     

Does Syntactic Alignment Effectively Influence How Speakers Are Perceived by Their Conversation Partner?

The way we talk can influence how we are perceived by others. Whereas previous studies have started to explore the influence of social goals on syntactic alignment, in the current study, we additionally investigated whether syntactic alignment effectively influences conversation partners’ perception of the speaker. To this end, we developed a novel paradigm in which we can measure the effect of social goals on the strength of syntactic alignment for one participant (primed participant), while simultaneously obtaining usable social opinions about them from their conversation partner (the evaluator). In Study 1, participants’ desire to be rated favorably by their partner was manipulated by assigning pairs to a Control (i.e., primed participants did not know they were being evaluated) or Evaluation context (i.e., primed participants knew they were being evaluated). Surprisingly, results showed no significant difference in the strength with which primed participants aligned their syntactic choices with their partners’ choices. In a follow-up study, we used a Directed Evaluation context (i.e., primed participants knew they were being evaluated and were explicitly instructed to make a positive impression). However, again, there was no evidence supporting the hypothesis that participants’ desire to impress their partner influences syntactic alignment. With respect to the influence of syntactic alignment on perceived likeability by the evaluator, a negative relationship was reported in Study 1: the more primed participants aligned their syntactic choices with their partner, the more that partner decreased their likeability rating after the experiment. However, this effect was not replicated in the Directed Evaluation context of Study 2. In other words, our results do not support the conclusion that speakers’ desire to be liked affects how much they align their syntactic choices with their partner, nor is there convincing evidence that there is a reliable relationship between syntactic alignment and perceived likeability.     

Subcellular structure of bovine thyroid gland. A study on bovine thyroid membranes by buoyant-density-gradient centrifugation in a B-XIV zonal rotor.

A combined mitochondrial and light mitochondrial fraction and a microsomal fraction were isolated from bovine thyroid gland and fractionated further in a B-XIV zonal rotor. A density gradient ranging from 20 to 50% (w/w) sucrose was used. The rotor was operated for 3 h at 45 000 rev./min. All manipulations were performed at 4 degrees C and at pH 7.4. 2. Membranous material was recovered in two zones: zone I, containing microsomal material derived from both smooth endoplasmic reticulum and plasma membranes and probably also from other smooth membranes; zone II, containing material from rough endoplasmic reticulum. 3. Increasing the pH of the medium up to 8.6, or the addition of Mg2+ to the medium resulted in the formation of a single zone at intermediate densities (aggregation of membranes?). An analogous effect was obtained after treatment with Pb (NO3) 2. 4. In the presence of heparin (50 i.u./ml) the bulk of the membranes was found in zone I. This was due to the release of ribosomes from the rough endoplasmic reticulum.     

On the binding of dolichol by human serum

The presence of a dolichol binding system is demonstrated in human serum. The dolichol binding exhibits normal saturation kinetics with an apparent affinity constant Kd of 6.9 X 10(-6) M. Optimal binding is obtained at pH 7.4 and 5 degrees C. After binding the [3H]dolichol cannot be chased by unlabelled dolichol. The selectivity is examined by competition studies showing that only dolichyl derivatives equally compete for binding sites. From buoyant density centrifugation and gel filtration it is deduced that the dolichol binding is due to a serum protein fraction, displaying the characteristics of VLDL.