Computational Thinking Is More about Thinking than Computing.

Computational thinking is widely recognized as important, not only to those interested in computer science and mathematics but also to every student in the twenty-first century. However, the concept of computational thinking is arguably complex; the term itself can easily lead to direct connection with "computing" or "computer" in a restricted sense. In this editorial, we build on existing research about computational thinking to discuss it as a multi-faceted theoretical nature. We further present computational thinking, as a model of thinking, that is important not only in computer science and mathematics, but also in other disciplines of STEM and integrated STEM education broadly.

Validation of a high-throughput, automated electrophysiology platform for the screening of nicotinic agonists and antagonists.

High-throughput compound screening using electrophysiology-based assays represents an important tool for biomedical research and drug discovery programs. The recent development and availability of devices capable of performing high-throughput electrophysiology-based screening have brought the need to validate these tools by producing data that are consistent with results obtained with conventional electrophysiological methods. In this study, we compared the response properties of hα3ß4 and hα4ß2 nicotinic receptors to their endogenous ligand acetylcholine (ACh) using three separate electrophysiology platforms: Dynaflow (low-throughput, manual system), PatchXpress 7000A (medium-throughput automated platform), and IonWorks Barracuda (high-throughput automated platform). We found that despite the differences in methodological approaches between these technologies, the EC(50) values from the ACh dose-response curves were consistent between all three platforms. In addition, we have validated the IonWorks Barracuda for both competitive and uncompetitive inhibition assays by using the competitive nicotinic antagonist dihydro-beta-erythroidin (DHßE) and uncompetitive nicotinic antagonist mecamylamine. Furthermore, we have demonstrated the utility of a custom-written algorithm for generating dose-response curves from multiple extrapolated current metrics that allows for discriminating between competitive and uncompetitive inhibition while maintaining high-throughput capacity. This study provides validation of the consistency of results using low-, medium-, and high-throughput electrophysiology platforms and supports their use for screening nicotinic compounds.

Functional and structural interaction of (-)-reboxetine with the human α4ß2 nicotinic acetylcholine receptor.

The interaction of the selective norepinephrine reuptake inhibitor (-)-reboxetine with the human α4ß2 nicotinic acetylcholine receptor (nAChR) in different conformational states was studied by several functional and structural approaches. Patch-clamp and Ca(2+)-influx results indicate that (-)-reboxetine does not activate hα4ß2 nAChRs via interaction with the orthosteric sites, but inhibits agonist-induced hα4ß2 activation by a noncompetitive mechanism. Consistently, the results from the electrophysiology-based functional approach suggest that (-)-reboxetine may act via open channel block; therefore, it is capable of producing a use-dependent type of inhibition of the hα4ß2 nAChR function. We tested whether (-)-reboxetine binds to the luminal [(3)H]imipramine site. The results indicate that, although (-)-reboxetine binds with low affinity to this site, it discriminates between the resting and desensitized hα4ß2 nAChR ion channels. Patch-clamp results also indicate that (-)-reboxetine progressively inhibits the hα4ß2 nAChR with two-fold higher potency at the end of one-second application of agonist, compared with the peak current. The molecular docking studies show that (-)-reboxetine blocks the ion channel at the level of the imipramine locus, between M2 rings 6' and 14'. In addition, we found a (-)-reboxetine conformer that docks in the helix bundle of the α4 subunit, near the middle region. According to molecular dynamics simulations, (-)-reboxetine binding is stable for both sites, albeit less stable than imipramine. The interaction of these drugs with the helix bundle might alter allostericaly the functionality of the channel. In conclusion, the clinical action of (-)-reboxetine may be produced (at least partially) by its inhibitory action on hα4ß2 nAChRs.

Differential pharmacologies of mecamylamine enantiomers: positive allosteric modulation and noncompetitive inhibition.

(+/-)-Mecamylamine is a racemic mixture of a widely used brain-permeant noncompetitive inhibitor of muscle-type and neuronal nicotinic receptors (NNRs). The present studies evaluated whether the stereoisomers of this drug show different profiles for inhibition of the high-sensitivity (HS) and low-sensitivity (LS) isoforms of the human alpha4beta2 NNR subtype expressed in subclonal human epithelial 1 cells. We found that at low concentrations (micromolar range), TC-5214 [S-(+)-mecamylamine] was more effective than TC-5213 [R-(-)-mecamylamine] in inhibiting the LS alpha4beta2 NNRs. In addition, we demonstrated that TC-5214 potentiated and TC-5213 inhibited agonist-induced activation of HS alpha4beta2 NNRs. The stereoselectivity of mecamylamine enantiomers at HS and LS alpha4beta2 receptors demonstrates that TC-5214 is the preferred stereoisomer for selective activation of HS, whereas it is more effective in suppressing LS receptor function. This feature could be relevant to therapeutic applications where such a selective mechanism of action is required.

A direct comparison of patient and force-controlled simulator total knee replacement kinematics.

The need to critically evaluate the efficacy of current total knee replacement (TKR) wear testing methodologies is great. Proposed international standards for TKR wear simulation have been drafted, yet their methods continue to be debated. The "gold standard" to which all TKR wear testing methodologies should be compared is measured in vivo TKR performance in patients. The current study compared patient TKR kinematics from fluoroscopic analysis and simulator TKR kinematics from force-controlled wear testing to quantify similarities in clinical ranges of motion and contact bearing kinematics and to evaluate the proposed ISO force-controlled wear testing methodology. The treadmill walking kinematics from eight well-functioning, 13 month average post-op patients were compared to the 2 million cycle interval walking cycle kinematics from a force-controlled (Instron/Stanmore Knee Joint Simulator, Instron, Canton, MA) knee simulator using identical implant designs (Natural Knee II, Standard Congruent, Zimmer, Warsaw, IN). The in vivo and simulator data showed good agreement in kinematic patterns and ranges of clinical motion. Tribologically the data sets showed similar contact pathway ranges of motion and wear travel distances per cycle. Surgical and simulator alignments of the implant systems were determined to be a contributing factor in observed kinematic differences. This study's statistical findings offer supporting evidence that the simulation of in vivo walking cycle wear kinematics can be accurately reproduced with a force controlled testing methodology.