513 research outputs found

    Experimentation and self learning in continuous database marketing

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    We present a method for continuous database marketing that identifies target customers for a number of marketing offers using predictive models. The algorithm then selects the appropriate offer for the customer. Experimental design principles are encapsulated to capture more information that will be used to monitor and refine the predictive models. The updated predictive models are then used for the next round of marketing offers.<br /

    Towards a general formulation of lazy constraints

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    A systemic approach to the database marketing process

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    The role of database marketing (DBM) has become increasingly important for organisations that have large databases of information on customers with whom they deal directly. At the same time, DBM models used in practice have increased in sophistication. This paper examines a systemic view of DBM and the role of analytical techniques within DBM. It extends existing process models to develop a systemic model that encompasses the increased complexity of DBM in practice. The systemic model provides a framework to integrate data mining, experimental design and prioritisation decisions. This paper goes on to identify opportunities for research in DBM, including DBM process models used in practice, the use of evolutionary operations techniques in DBM, prioritisation decisions, and the factors that surround the uptake of DBM.<br /

    Computational Design of Peptides to Block Binding of the SARS-CoV-2 Spike Protein to Human ACE2

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    The outbreak of COVID-19 has now become a global pandemic and it continues to spread rapidly worldwide, severely threatening lives and economic stability. Making the problem worse, there is no specific antiviral drug that can be used to treat COVID-19 to date. SARS-CoV-2 initiates its entry into human cells by binding to angiotensin-converting enzyme 2 (hACE2) via the receptor binding domain (RBD) of its spike protein. Therefore, molecules that can block SARS-CoV-2 from binding to hACE2 may potentially prevent the virus from entering human cells and serve as an effective antiviral drug. Based on this idea, we designed a series of peptides that can strongly bind to SARS-CoV-2 RBD in computational experiments. Specifically, we first constructed a 31-mer peptidic scaffold by linking two fragments grafted from hACE2 (a.a. 22-44 and 351-357) with a linker glycine, and then redesigned the peptide sequence to enhance its binding affinity to SARS-CoV-2 RBD. Compared with several computational studies that failed to identify that SARS-CoV-2 shows higher binding affinity for hACE2 than SARS-CoV, our protein design scoring function, EvoEF2, makes a correct identification, which is consistent with the recently reported experimental data, implying its high accuracy. The top designed peptide binders exhibited much stronger binding potency to hACE2 than the wild-type (−53.35 vs. −46.46 EvoEF2 energy unit for design and wild-type, respectively). The extensive and detailed computational analyses support the high reasonability of the designed binders, which not only recapitulated the critical native binding interactions but also introduced new favorable interactions to enhance binding. Due to the urgent situation created by COVID-19, we share these computational data to the community, which should be helpful to develop potential antiviral peptide drugs to combat this pandemic.https://deepblue.lib.umich.edu/bitstream/2027.42/155559/1/Huang_Pearce_and_Zhang.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155559/3/DeepBluepermissions_agreement-CCBYandCCBY-NC_ORCID_Zhang.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155559/4/license_rdf.rdfDescription of Huang_Pearce_and_Zhang.pdf : Article preprintDescription of DeepBluepermissions_agreement-CCBYandCCBY-NC_ORCID_Zhang.pdf : Deep Blue sharing agreemen

    Human carboxylesterases HCE1 and HCE2: Ontogenic expression, inter-individual variability and differential hydrolysis of oseltamivir, aspirin, deltamethrin and permethrin

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    Carboxylesterases hydrolyze chemicals containing such functional groups as a carboxylic acid ester, amide and thioester. The liver contains the highest carboxylesterase activity and expresses two major carboxylesterases: HCE1 and HCE2. In this study, we analyzed 104 individual liver samples for the expression patterns of both carboxylesterases. These samples were divided into three age groups: adults (≥ 18 years of age), children (0 days–10 years) and fetuses (82–224 gestation days). In general, the adult group expressed significantly higher HCE1 and HCE2 than the child group, which expressed significantly higher than the fetal group. The age-related expression was confirmed by RT-qPCR and Western immunoblotting. To determine whether the expression patterns reflected the hydrolytic activity, liver microsomes were pooled from each group and tested for the hydrolysis of drugs such as oseltamivir and insecticides such as deltamethrin. Consistent with the expression patterns, adult microsomes were ∼4 times as active as child microsomes and 10 times as active as fetal microsomes in hydrolyzing these chemicals. Within the same age group, particularly in the fetal and child groups, a large inter-individual variability was detected in mRNA (430-fold), protein (100-fold) and hydrolytic activity (127-fold). Carboxylesterases are recognized to play critical roles in drug metabolism and insecticide detoxication. The findings on the large variability among different age groups or even within the same age group have important pharmacological and toxicological implications, particularly in relation to pharmacokinetic alterations of ester drugs in children and vulnerability of fetuses and children to pyrethroid insecticides

    Different current intensities of anodal transcranial direct current stimulation do not differentially modulate motor cortex plasticity

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    Transcranial direct current stimulation (tDCS) is a noninvasive technique that modulates the excitability of neurons within the motor cortex (M1). Although the aftereffects of anodal tDCS on modulating cortical excitability have been described, there is limited data describing the outcomes of different tDCS intensities on intracortical circuits. To further elucidate the mechanisms underlying the aftereffects of M1 excitability following anodal tDCS, we used transcranial magnetic stimulation (TMS) to examine the effect of different intensities on cortical excitability and short-interval intracortical inhibition (SICI). Using a randomized, counterbalanced, crossover design, with a one-week wash-out period, 14 participants (6 females and 8 males, 22&ndash;45 years) were exposed to 10 minutes of anodal tDCS at 0.8, 1.0, and 1.2&thinsp;mA. TMS was used to measure M1 excitability and SICI of the contralateral wrist extensor muscle at baseline, immediately after and 15 and 30 minutes following cessation of anodal tDCS. Cortical excitability increased, whilst SICI was reduced at all time points following anodal tDCS. Interestingly, there were no differences between the three intensities of anodal tDCS on modulating cortical excitability or SICI. These results suggest that the aftereffect of anodal tDCS on facilitating cortical excitability is due to the modulation of synaptic mechanisms associated with long-term potentiation and is not influenced by different tDCS intensities
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