Prediction, Explanation, and Control: The Use of Mental Models in Dynamic Environments.

The abilities to predict, explain, and control might arise out of operations on a common underlying representation or, conversely, from independent cognitive processes. We developed a novel experimental paradigm to explore how individuals might use probabilistic mental models in these three tasks, under varying levels of complexity and uncertainty. Participants interacted with a simple chatbot defined by a finite-state machine, and were then tested on their ability to predict, explain, and control the chatbot's responses. When full information was available, performance varied significantly across the tasks, with control proving most robust to increased complexity, and explanation being the most challenging. In the presence of hidden information, however, performance across tasks equalized, and participants demonstrated an alternative neglect bias, i.e., a tendency to ignore less likely possibilities. A second, within-subject experimental design then looked for correlations between abilities. We did not find strong correlations, but the challenges of the task for the subjects limited our statistical power. To understand these effects better, a final experiment investigated the possibility of cross-training, skill transfer, or "zero-shot" performance: how well a participant, explicitly trained on one of the three tasks, could perform on the others without additional training. Here we found strong asymmetries: participants trained to control gained generalizable abilities to both predict and explain, while training on either prediction or explanation did not lead to transfer. This cross-training experiment also revealed correlations in performance; most notably between control and prediction. Our findings highlight the complex role of mental models, in contrast to task-specific heuristics, when information is partially hidden, and suggest new avenues for research into situations where the acquisition of general purpose mental models may provide a unifying explanation for a variety of cognitive abilities.

Teaching categories via examples and explanations.

People often learn categories through interaction with knowledgeable others who may use verbal explanations, visual exemplars, or both, to share their knowledge. Verbal and nonverbal means of pedagogical communication are commonly used in conjunction, but their respective roles are not fully understood. In this work, we studied how well these modes of communication work with different category structures. We conducted two experiments to investigate the effect of perceptual confusability and stimulus dimensionality on the effectiveness of verbal, exemplar-based, and mixed communication. One group of participants - teachers - learned a categorization rule and prepared learning materials for the students. Students studied the materials prepared for them and then demonstrated their knowledge on test stimuli. All communication modes were generally successful, but not equivalent, with mixed communication consistently showing best results. When teachers were free to generate as many visual exemplars or words as they wish, verbal and exemplar-based communication showed similar performance, although the verbal channel was slightly less reliable in situations requiring high perceptual precision. At the same time, verbal communication was better suited to handling high-dimensional stimuli when communication volume was restricted. We believe that our work serves as an important step towards studying language as a means for pedagogical category leaning.

Violence Exposure, Posttraumatic Stress, and Subjective Well-Being in a Sample of Russian Adults: A Facebook-Based Study.

Exposure to violence has been shown to negatively affect mental health and well-being. The goal of this Facebook-based study was to describe the rates of exposure to violence in a sample of Russian adults and to assess the impact of these experiences on subjective well-being and victimization-related psychological distress. Three types of victimization were assessed: physical assault by a stranger, physical assault by someone known to victim, and nonconsensual sexual experiences. The 5-item World Health Organization Well-Being Index (WHO-5) was used to assess subjective well-being, and Primary Care PTSD Screen (PC-PTSD) was employed as an indicator of victimization-related psychological distress. Data were obtained from 6,724 Russian-speaking Facebook users. Significant levels of lifetime victimization were reported by the study participants. Lifetime physical assault by a stranger, physical assault by someone known to victim, and sexual assault were reported by 56.9%, 64.2%, and 54.1% of respondents, respectively. Respondents exposed to violence were more likely to report posttraumatic stress symptoms and lower levels of subjective well-being. Participants who were exposed to at least one type of violence were more likely to experience symptoms of traumatic stress (U = 1,794,250.50, p < .001, d = 0.35). Exposure to multiple forms of violence was associated with more severe traumatic stress symptoms (rs = .257, p < .001). Well-being scores were significantly lower among participants exposed to violence (t = 8.37, p < .001, d = 0.31). The study demonstrated that violence exposure is associated with reduced well-being among Russian adults. Our findings highlight the negative impact of violence exposure on subjective well-being and underscore the necessity to develop programs addressing violence exposure in Russian populations.

Implicit learning in attractiveness evaluation: The role of conformity and analytical processing.

We address the question how people's opinion and features of information interact in the process of indirect social influence. Implicit learning was considered as a mechanism for conformity in social perception. We carried out 2 experiments using a hidden covariation detection paradigm. In a learning phase, participants memorized a set of female photographs presented together with their attractiveness ratings. The ratings correlated with the hairstyle of the photographed women. The participants who did not consciously detect this correlation demonstrated a systematic bias toward the correlation when evaluating the new stimulus persons. Information about the source of the ratings in the learning phase (other people's opinions or nonsocial sources) did not modulate learning. Learning was not observed when participants critically evaluated the ratings during the memorization phase. The study shows that (a) conformity may be based not only on reinforcement learning mechanism (as was previously suggested) but also on unsupervised implicit learning; (b) implicit learning occurs automatically irrespective of the context (social or not); and (c) a critical attitude toward learned material may prevent implicit learning from being manifested in a test phase. We conclude that indirect social influence may be affected by people's opinion toward the provided information. The study contributes to both implicit learning and social perception research. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Recombinant C1 Esterase Inhibitor Reduces Cytokine Storm in an Ex Vivo Whole Blood Model.

C1 esterase inhibitor (C1INH) is an abundant component of blood plasma (the average concentration is 250 mg/L); it is known to be involved in several biological processes, for instance, in the regulation of the coagulation system, adhesion of leukocytes on endothelial cells, and in the regulation of complement and kallikrein cascades. Lately, the role of C1INH in immunomodulation has gained considerable attention. We used an ex vivo whole blood model to examine the influence of C1INH and its mutated variants on the inflammatory cytokines interleukin (IL)-6, tumor necrosis factor-α (TNFα), and IL-1ß. The present study demonstrated for the first time that recombinant C1INH or its Seprin domain can downregulate bacterial endotoxin induced IL-6 release. We also observed that unstructured N-terminal domain of C1INH downregulates the release of IL-1ß and TNFα, but not IL-6. Our results suggest that C1INH may have therapeutic potential for treatment of inflammatory conditions.

A new hybrid protein for production of recombinant bacteriorhodopsin in Escherichia coli.

Unique properties of bacteriorhodopsin, namely, photochromism and high thermal stability, make this protein an attractive target for physico-chemical studies, as well as for various biotechnological applications. Using Mistic as a suitable carrier for insertion of recombinant membrane proteins into cytoplasmic membrane of Escherichia coli, we developed a system for overexpression of bacteriorhodopsin and worked out an efficient procedure for its purification and renaturation with the final yield of 120 mg/l of refolded protein, which is the highest value reported to date for bacteriorhodopsin produced in E. coli. Functional activity of recombinant bacteriorhodopsin was confirmed by spectroscopic and electrochemical assays.

Producing human mechano growth factor (MGF) in Escherichia coli.

MGF is a product of a unique muscle-specific splice variant of IGF1 gene (insulin-like growth factor). Its peculiar feature is a specific E-peptide, a 16 a.a. strand at the C-terminus. MGF increases cellular proliferation and inhibits terminal differentiation of myoblasts necessary for the secondary myotube formation. Previous analysis of physiological effects of MGF was performed using indirect methods such as RT-PCR based examination of the transcript contents in normal tissues, adenovirus-mediated DNA delivery and synthetic E-domain administration. Here, we describe isolation and purification of recombinant MGF thus allowing for the first time the possibility of direct examining MGF effects. The recombinant MGF of directly examining--was expressed in Escherichia coli as inclusion bodies (about 100-200mg/l), purified and refolded. Biological activity of refolded MGF was analyzed in vitro in proliferation assays with normal human myoblasts. As a result of our work, it has become possible to generate a standard MGF control with characterized activity and a ready-to use MGF test-system neither of which have been previously described. Our data open opportunities for the future works on MGF characterization and to the development of a powerful and highly specific therapeutic agent potentially applicable for muscle growth up-regulation, post-trauma muscle repair, age and hereditary myodystrophy mitigation and in sport medicine.

Recombinant human insulin IX. Investigation of factors, influencing the folding of fusion protein-S-sulfonates, biotechnological precursors of human insulin.

The peculiarities of molecular structures and the influence of reaction conditions on the folding efficiency of fusion proteins-biotechnological precursors of human insulin, expressed in Escherichia coli as inclusion bodies have been investigated. The fusion proteins contained proinsulin sequence with various leader peptides connected by an Arg residue to the insulin B-chain. The kind and the size of leader peptide do not have essential influence on folding efficiency. However, the efficiency of protein folding depends on the location of the (His)6 site, which is used for metal-chelating affinity chromatography. In our study the protein folding depends on the reaction medium composition (including additives), the presence of accompanied cell components, pH, temperature, concentrations of protein, and redox agents. A negative influence of nucleic acid and heavy metal ions on folding has been found. S-sulfonated fusion protein has proinsulin-like secondary structure (by CD-spectroscopy data) that is the key point for 95% efficient folding proceeding. Folded fusion proteins are transformed into insulin by enzymatic cleavage.

Methods for preparation of recombinant cytokine proteins V. mutant analogues of human interferon-gamma with higher stability and activity.

Mutant analogues of recombinant human immune interferon (IFN-gamma) with higher stability and biological activity were prepared. Depending on the analogue, protein structure modification might involve introduction of an intramonomer disulfide bond (through replacements of Glu7Cys and Ser69Cys), C-terminal shortening by 10 amino acid residues, as well as Gln133Leu substitution in truncated variant. Isolation, purification, and renaturation of the IFN-gamma analogues expressed in Escherichia coli as inclusion bodies were performed according to the scheme developed earlier for wild-type protein. The main idea of this scheme is to remove cellular impurities before recombinant protein renaturation. Folding kinetics of IFN-gamma was studied by reversed-phase HPLC. IFN-gamma and mutant proteins were characterized by their thermal stability and biological activity. Introduction of the intramolecular disulfide bond together with C-terminal shortening and replacement of C-terminal residue was shown to result in increasing the thermal stability by 19 degrees C and four times enhancement of biological activity compared with intact IFN-gamma molecule.