Testing Someone Else’s Intelligence: From Regimentation to Freedom1

This article discusses the trend in the development of testing from maximum regimentation of the test-takers’ activity (where they solve problems clearly formulated by the creator with a single correct answer) to diagnostic problematic situations that are very new and indefinite with an open beginning and an open end. With increasing frequency, the open beginning used in testing presupposes a freedom of independent formulation of one’s own research questions of the reality being studied and a search for answers while interacting with that reality. The emergence of mass testing of exploratory behavior is a reflection of the conviction that one of the key abilities that will be required in the very near future is the ability to cope with uncertainty and novelty, including by actively investigating them.

The discussion deals with the problems of testing intelligence and creativity in conditions of novelty and uncertainty, including the “judging problem.” It is pointed out that any thinking test, especially a test of creative thinking, is also an implicit (albeit perhaps not conscious) claim by its developers that their wisdom is virtually unsurpassed. After all, it is assumed that any person’s intelligence and creativity that unfold in a new situation may be described in the context of the model produced by the creative intellect of the test’s developer and, hence, by a more powerful “superintellect.” The errors that are practically inevitable with such an approach can be corrected in a dialog among various groups of researchers or, to the contrary, may be deepened if criticism is shut off.

The article analyzes a fundamental methodological error of creativity testing—the “standard list of creative answers” drawn up by the test-maker in advance, against which the participants’ solutions are checked. This error is explored in the case of an invention-oriented task in the international scholastic test PISA 2012, based on which the education ratings of countries are constructed.

An optimistic thesis is offered: no matter how successful testing is, humankind will never be fully prepared to determine its creative potential, due to its forward development. Without diagnostic tools, however, it will be far less prepared; they are a new and important part of that potential.     

Molecular dynamics complemented by site-directed mutagenesis reveals significant difference between the interdomain salt bridge networks stabilizing oligopeptidases B from bacteria and protozoa in their active conformations

Abstract

Oligopeptidases B (OpdBs) are trypsin-like peptidases from protozoa and bacteria that belong to the prolyl oligopeptidase (POP) family. All POPs consist of C-terminal catalytic domain and N-terminal β-propeller domain and exist in two major conformations: closed (active), where the domains and residues of the catalytic triad are positioned close to each other, and open (non-active), where two domains and residues of the catalytic triad are separated. The interdomain interface, particularly, one of its salt bridges (SB1), plays a role in the transition between these two conformations. However, due to double amino acid substitution (E/R and R/Q), this functionally important SB1 is absent in γ-proteobacterial OpdBs including peptidase from Serratia proteamaculans (PSP). In this study, molecular dynamics was used to analyze inter- and intradomain interactions stabilizing PSP in the closed conformation, in which catalytic H652 is located close to other residues of the catalytic triad. The 3D models of either wild-type PSP or of mutant PSPs carrying activating mutations E125A and D649A in complexes with peptide-substrates were subjected to the analysis. The mechanism that regulates transition of H652 from active to non-active conformation upon domain separation in PSP and other γ-proteobacterial OpdB was proposed. The complex network of polar interactions within H652-loop/C-terminal α-helix and between these areas and β-propeller domain, established in silico, was in a good agreement with both previously published results on the effects of single-residue mutations and new data on the effects of the activating mutations on each other and on the low active mutant PSP-K655A.

Communicated by Ramaswamy H. Sarma     

Discovery of potent, selective, and orally bioavailable oxadiazole-based dipeptidyl peptidase IV inhibitors

A novel series of oxadiazole based amides have been shown to be potent DPP-4 inhibitors. The optimized compound 43 exhibited excellent selectivity over a variety of DPP-4 homologs.     

Novel 5-azaindole factor VIIa inhibitors

The discovery and development of 5-azaindole factor VIIa inhibitors will be described.     

Factor VIIa inhibitors: improved pharmacokinetic parameters

Efforts to improve the potency and pharmacokinetic properties of small molecule factor VIIa inhibitors are described. Small structural modifications to existing leads allow the modulation of half-life and clearance, potentially making these compounds suitable candidates for drug development.     

Scaling of diastolic intraventricular pressure gradients is related to filling time duration

In early diastole, pressure is lower in the apex than in the base of the left ventricle (LV). This early intraventricular pressure difference (IVPD) facilitates LV filling. We assessed how LV diastolic IVPD and intraventricular pressure gradient (IVPG), defined as IVPD divided by length, scale to the heart size and other physiological variables. We studied 10 mice, 10 rats, 5 rabbits, 12 dogs, and 21 humans by echocardiography. Color Doppler M-mode data were postprocessed to reconstruct IVPD and IVPG. Normalized LV filling time was calculated by dividing filling time by RR interval. The relationship between IVPD, IVPG, normalized LV filling time, and LV end-diastolic volume (or mass) as fit to the general scaling equation Y = kM beta, where M is LV heart size parameter, Y is a dependent variable, k is a constant, and beta is the power of the scaling exponent. LV mass varied from 0.049 to 194 g, whereas end-diastolic volume varied from 0.011 to 149 ml. The beta values relating normalized LV filling time with LV mass and end-diastolic volume were 0.091 (SD 0.011) and 0.083 (SD 0.009), respectively (P < 0.0001 vs. 0 for both). The beta values relating IVPD with LV mass and end-diastolic volume were similarly significant at 0.271 (SD 0.039) and 0.243 (SD 0.0361), respectively (P < 0.0001 vs. 0 for both). Finally, beta values relating IVPG with LV mass and end-diastolic volume were -0.118 (SD 0.013) and -0.104 (SD 0.011), respectively (P < 0.0001 vs. 0 for both). As a result, there was an inverse relationship between IVPG and normalized LV filling time (r = -0.65, P < 0.001). We conclude that IVPD decrease, while IVPG increase with decreasing animal size. High IVPG in small mammals may be an adaptive mechanism to short filling times.     

Ammonium Concentrations in Produced Waters from a Mesothermic Oil Field Subjected to Nitrate Injection Decrease through Formation of Denitrifying Biomass and Anammox Activity

Community analysis of a mesothermic oil field, subjected to continuous field-wide injection of nitrate to remove sulfide, with denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes indicated the presence of heterotrophic and sulfide-oxidizing, nitrate-reducing bacteria (hNRB and soNRB). These reduce nitrate by dissimilatory nitrate reduction to ammonium (e.g., Sulfurospirillum and Denitrovibrio) or by denitrification (e.g., Sulfurimonas, Arcobacter, and Thauera). Monitoring of ammonium concentrations in producing wells (PWs) indicated that denitrification was the main pathway for nitrate reduction in the field: breakthrough of nitrate and nitrite in two PWs was not associated with an increase in the ammonium concentration, and no increase in the ammonium concentration was seen in any of 11 producing wells during periods of increased nitrate injection. Instead, ammonium concentrations in produced waters decreased on average from 0.3 to 0.2 mM during 2 years of nitrate injection. Physiological studies with produced water-derived hNRB microcosms indicated increased biomass formation associated with denitrification as a possible cause for decreasing ammonium concentrations. Use of anammox-specific primers and cloning of the resulting PCR product gave clones affiliated with the known anammox genera “Candidatus Brocadia” and “Candidatus Kuenenia,” indicating that the anammox reaction may also contribute to declining ammonium concentrations. Overall, the results indicate the following: (i) that nitrate injected into an oil field to oxidize sulfide is primarily reduced by denitrifying bacteria, of which many genera have been identified by DGGE, and (ii) that perhaps counterintuitively, nitrate injection leads to decreasing ammonium concentrations in produced waters.Nitrate is injected into oil fields to remedy souring (34, 37, 38), the reduction of sulfate to sulfide coupled to the oxidation of oil organics that is catalyzed by resident sulfate-reducing bacteria (SRB). Nitrate acts by stimulating heterotrophic nitrate-reducing bacteria (hNRB) and sulfide-oxidizing, nitrate-reducing bacteria (soNRB), collectively referred to as NRB. The former can compete with SRB for the same oil organics, whereas the latter remove produced sulfide by oxidation to sulfur and sulfate. Both groups reduce nitrate to nitrite and then to either N₂ or ammonium by denitrification or dissimilatory nitrate reduction to ammonium (DNRA), respectively (7, 13). The produced nitrite strongly inhibits dissimilatory sulfite reductase (Dsr), the enzyme responsible for sulfide production by SRB. Hence, nitrite can be regarded as a magic bullet, which targets SRB metabolism exactly where desired. Some SRB can overcome nitrite inhibition by an Nrf-type periplasmic nitrite reductase, which reduces nitrite to ammonium, preventing its inflow into the cytoplasm, where Dsr is located (10, 12).Oil fields are ideal windows into the subsurface, allowing monitoring of produced waters for the presence of chemical compounds and microbes that are active in the sulfur and nitrogen cycles (8, 9, 26, 28, 34, 37, 38). The Enermark Medicine Hat Glauconitic C field (the Enermark field) in southeastern Alberta, Canada, produces oil from a depth of 850 m (down-hole temperature of 30°C) through produced water reinjection (PWRI) (see Fig. ​Fig.1).1). In 2007, the water plants (WPs) had an output of approximately 2,500 m³ of injection water per day, of which 25% was make-up water (MW). The latter was mostly the purified and chlorinated water from the municipal sewage plant and is the only input of sulfate (4 to 5 mM) in the system, giving the injection water an average sulfate concentration of ∼1 mM. Although oil (1,000 m³/day) has been produced through PWRI since 2000, souring did not become a problem until 2006. To control souring, a 45% (wt/wt) calcium nitrate concentrate has been injected since May 7, 2007 (week 1), as follows: (i) continuous field-wide injection of 2.4 mM nitrate at the WPs, which is still going on today, (ii) application of batches of high nitrate concentration (1 h/week; peak concentration of 760 mM) at a single injection well (IW) (14-IW) from week 33 to 101, and (iii) field-wide injection of pulses of weekly alternating high (14 mM) or low (2.4 mM) nitrate concentrations at the WPs from week 64 to 96. Continuous nitrate injection lowered the sulfide concentration, but this was followed by a recovery (39). Zero sulfide at two PWs was obtained through batchwise or pulsed injection. The results indicated that continuous injection leads to microbial zonation (39), in which hNRB grow in the near-injection wellbore region (see Fig. ​Fig.1,1, zone A) whereas SRB grow deeper in the reservoir (see Fig. ​Fig.1,1, zone B). This causes injected nitrate to be primarily reduced by hNRB through oxidation of oil components, like toluene (20), without reaching the sulfide-producing zones deeper in the reservoir.Open in a separate windowFIG. 1.Schematic representation of oil production through PWRI. The oil-water mixture pumped up at producing wells (PW) is separated, and the water is piped to a water plant, where it is mixed with make-up water. The resulting injection water is injected at injection wells. Sampling points are indicated (*). Two points of nitrate injection are indicated at the WP and at a specific IW. The Enermark field had 3 MW sources, 3 WPs, 55 IWs, and 107 PWs. Many of these are horizontal wells (not shown). The oil-producing subsurface (for the Enermark field: depth, 850 m; resident temperature, 30°C) has been divided into zones A to C, thought to harbor different microbial groups as outlined in the text.The effect of nitrate injection on aqueous sulfide concentrations emerging in produced waters from the Enermark field has thus been extensively analyzed (39). We report here on the microbial community present in these waters during nitrate injection as determined by denaturing gradient gel electrophoresis (DGGE) and on the fate of the injected nitrate by monitoring ammonium concentrations in produced and injection waters.     

Synthesis and evaluation of 3′-azido-2′,3′-dideoxypurine nucleosides as inhibitors of human immunodeficiency virus

Based on the promising drug resistance profile and potent anti-HIV activity of β-d-3′-azido-2′,3′-dideoxyguanosine, a series of purine modified nucleosides were synthesized by a chemical transglycosylation reaction and evaluated for their antiviral activity, cytotoxicity, and intracellular metabolism. Among the synthesized compounds, several show potent and selective anti-HIV activity in primary lymphocytes.