Psychophysiological strategies for enhancing performance through imagery-skin conductance level analysis in guided vs. self-produced imagery

Athletes need to achieve their optimal level of arousal for peak performance. Visualization or mental rehearsal (i.e., Imagery) often helps to obtain an appropriate level of activation, which can be detected by monitoring Skin Conductance Level (SCL). However, different types of imagery could elicit different amount of physiological arousal. Therefore, this study aims: (1) to investigate differences in SCL associated with two instructional modalities of imagery (guided vs. self-produced) and six different scripts; (2) to check if SCL could differentiate respondents according to their sport expertise. Thirty participants, aged between 14 and 42 years (M = 22.93; SD = 5.24), with different sport levels took part in the study. Participants listened to each previously recorded script and then were asked to imagine the scene for a minute. During the task, SCL was monitored. We analysed the mean value, variance, slope and number of fluctuations per minute of the electrodermal signal. Unsupervised machine learning models were used for measuring the resemblance of the signal. The Wilcoxon signed-rank test was used for distinguishing guided and self-produced imagery, and The Mann-Whitney U test was used for distinguishing results of different level athletes. We discovered that among others, self-produced imagery generates lower SCL, higher variance, and a higher number of fluctuations compared to guided imagery. Moreover, we found similarities of the SCL signal among the groups of athletes (i.e. expertise level). From a practical point of view, our findings suggest that different imagery instructional modalities can be implemented for specific purposes of mental preparation.

Enhancing Renal Tumor Detection: Leveraging Artificial Neural Networks in Computed Tomography Analysis

BACKGROUND Renal cell carcinoma is one of the most common cancers in Europe, with a total incidence rate of 18.4 cases per 100 000 population. There is currently significant overdiagnosis (11% to 30.9%) at times of planned surgery based on radiological studies. The purpose of this study was to create an artificial neural network (ANN) solution based on computed tomography (CT) images as an additional tool to improve the differentiation of malignant and benign renal tumors and to aid active surveillance. MATERIAL AND METHODS A retrospective study based on CT images was conducted. Axial CT images of 357 renal tumor cases were collected. There were 265 (74.2%) cases histologically proven to be malignant, while 34 (9.5%) cases were benign. Radiologists diagnosed 58 (16.3%) cases as angiomyolipoma (AML), based on characteristic appearance, not confirmed histopathologically. For ANN training, the arterial CT phase images were used. A total of 7207 arterial-phase images were collected, then cropped and added to the database with the associated diagnosis. For the test dataset (ANN validation), 38 cases (10 benign, 28 malignant) were chosen by subgroup randomization to correspond to statistical tumor type distribution. The VGG-16 ANN architecture was used in this study. RESULTS Trained ANN correctly classified 23 out of 28 malignant tumors and 8 out of 10 benign tumors. Accuracy was 81.6% (95% confidence interval, 65.7-92.3%), sensitivity was 82.1% (63.1-93.9%), specificity was 80.0% (44.4-97.5%), and F1 score was 86.8% (74.7-94.5%). CONCLUSIONS The created ANN achieved promising accuracy in differentiating benign vs malignant renal tumors.

Linear and Nonlinear Optical Properties of Azobenzene Derivatives Modified with an (Amino)naphthalene Moiety

The design of two-photon absorbing azobenzene (AB) derivatives has received much attention; however, the two-photon absorption (2PA) properties of bis-conjugated azobenzene systems are relatively less explored. Here, we present the synthesis of six azobenzene derivatives and three bis-azobenzenes substituted (or not) at para position(s) with one or two amino group(s). Their linear and nonlinear absorption properties are studied experimentally and theoretically. The switching behavior and thermal stability of the Z-isomer are studied for unsubstituted mono- (1a, 2a) and bis-azobenzene (3a) compounds, showing that when the length of the π system increases, the half-life of the Z-isomer decreases. Moreover, along with the increase of π-conjugation, the photochromic characteristics are impaired and the photostationary state (PSS) related to E-Z photoisomerization is composed of 89% of the Z-isomer for 2a and 26% of the Z-isomer for 3a. Importantly, the 2PA cross-section increases almost five-fold on extending the π-conjugation (2a vs 3a) and by about one order of magnitude when comparing two systems: the unsubstituted π-electron one (2a, 3a) with D-π-D (2c, 3c). This work clarifies the contribution of π-conjugation and substituent effects to the linear and nonlinear optical properties of mono- and bis-azobenzene compounds based on the experimental and theoretical approaches.

Neural Oscillation During Mental Imagery in Sport: An Olympic Sailor Case Study

The purpose of the current study was to examine the cortical correlates of imagery depending on instructional modality (guided vs. self-produced) using various sports-related scripts. According to the expert-performance approach, we took an idiosyncratic perspective analyzing the mental imagery of an experienced two-time Olympic athlete to verify whether different instructional modalities of imagery (i.e., guided vs. self-produced) and different scripts (e.g., training or competition environment) could differently involve brain activity. The subject listened to each previously recorded script taken from two existing questionnaires concerning imagery ability in sport and then was asked to imagine the scene for a minute. During the task, brain waves were monitored using EEG (32-channel g. Nautilus). Our findings indicate that guided imagery might induce higher high alpha and SMR (usually associated with selective attention), whereas self-produced imagery might facilitate higher low alpha (associated with global resting state and relaxation). Results are discussed in light of the neural efficiency hypothesis as a marker of optimal performance and transient hypofrontality as a marker of flow state. Practical mental training recommendations are presented.

Spontaneous electron emission vs dissociation in internally hot silver dimer anions

Referring to a recent experiment, we theoretically study the process of a two-channel decay of the diatomic silver anion (Ag₂ ^-), namely, the spontaneous electron ejection giving Ag₂ + e^- and the dissociation leading to Ag^- + Ag. The ground state potential energy curves of the silver molecules of diatomic neutral and negative ions were calculated using proper pseudo-potentials and atomic basis sets. We also estimated the non-adiabatic electronic coupling between the ground state of Ag₂ ^- and the ground state of Ag₂ + e^-, which, in turn, allowed us to estimate the minimal and mean values of the electron autodetachment lifetimes. The relative energies of the rovibrational levels allow the description of the spontaneous electron emission process, while the description of the rotational dissociation is treated with the quantum dynamics method as well as time-independent methods. The results of our calculations are verified by comparison with the experimental data.

Electronic structure and rovibrational predissociation of the 21Π state in KLi

Adiabatic potential energy curves of the 3¹Σ⁺, 3³Σ⁺, 2¹Π and 2³Π states correlating for large internuclear distance with the K(4s) + Li(2p) atomic asymptote were calculated. Lifetimes of the quasi-bound rovibrational states of the 2¹Π state were determined by explicit time propagation.

Electronic structure and time-dependent description of rotational predissociation of LiH

The adiabatic potential energy curves of the ¹Σ⁺ and ¹Π states of the LiH molecule were calculated. They correlate asymptotically to atomic states, such as 2s + 1s, 2p + 1s, 3s + 1s, 3p + 1s, 3d + 1s, 4s + 1s, 4p + 1s and 4d + 1s. A very good agreement was found between our calculated spectroscopic parameters and the experimental ones. The dynamics of the rotational predissociation process of the 1¹Π state were studied by solving the time-dependent Schrödinger equation. The classical experiment of Velasco [Can. J. Phys., 1957, 35, 1204] on dissociation in the 1¹Π state is explained for the first time in detail.

Angiotensin-converting enzyme activity and the ACE Alu polymorphism in autosomal dominant polycystic kidney disease

BACKGROUND

Previous studies concerning Alu I/D polymorphism in the ACE gene and ADPKD severity have used the Alu genotypes as a representative of the true biological variable, namely ACE activity. However, wide individual and ethnic differences in the proportion of variance in ACE activity explained by the I/D genotype may have confounded these studies. This investigation examines the association between ADPKD severity and ACE in terms of plasma enzyme activity and I/D genotypes in individuals from three different countries.

METHODS

Blood samples were collected from 307 ADPKD patients (116 Australian, 124 Bulgarian and 67 Polish) for determination of ACE activity levels and I/D genotypes. Chronic renal failure (CRF) was present in 117 patients and end-stage renal failure (ESRF) in 68 patients.

RESULTS

ACE activity was related to the I/D genotype, showing a dosage effect of the D allele (P=0.006). The proportion of variance due to the Alu polymorphism was 14%. No difference in ACE activity and I/D genotype distribution was found between patients with CRF versus normal renal function (P=0.494; P=0.576) or between those with ESRF versus those without ESRF (P=0.872; P=0.825). No effect of the I/D genotype on age at development and progression to renal failure (CRF; ESRF) was detected in the overall group, and in subgroups based on ethnic origin, linkage status and sex.

CONCLUSION

ACE is not likely to play a role as a determinant of ADPKD phenotype severity.

[Current opinions about the etiology and pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). I. Selected genetic aspects and mechanisms of cyst formation]

The aim of this study is to present in the chronological order evolution of opinions about the etiopathogenesis of Autosomal Dominant Polycystic Kidney Disease (ADPKD), with the special regard to the newest genetic investigations. Prevalence of this disease is estimated at 1:1000, and patients with ADPKD compose up to 10% patients, who need renal replacement therapy. Since 1957, when inheritance was defined by Daalgard as autosomal dominant, a rapid progression in investigations of genetic aspects of this disease has been done. Actually three genes responsible for the development of the disease are known: PKD1 gene located on the short arm of the chromosome 16 (isolated and described in 1994-1995), PKD2 gene, which is located on the long arm of the chromosome 4 (isolated in 1996) and exceptionally occurs PKD3 gene which is not mapped by linkage analysis neither on the PKD1 nor the PKD2. Loci for PKD3 gene is unknown up to now. Investigations, which have been done indicate dependence between genetic type of ADPKD and clinical picture of the disease. Majority of authors consider ADPKD1 as the severe form of the disease, although it is not a rule. The biggest emphasis has been also lay on the influence of other factors. Pathomechanisms of cyst formation in kidneys, the presence of which is pathognomonic for this disease has been better and better understood. Employment of modern diagnostic methods with combinations of the genetic analysis (especially linkage analysis) afford possibilities for early diagnosis of the disease among persons, who are kindreds of ADPKD family members and are at risk of the disease.

[Current opinions on the etiology and pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). II. Factors other than genetic factors which have an influence on disease course and selected clinical problems]

In the first part of this paper achievements in the genetic investigations of ADPKD and pathomechanism of cyst formation have been presented. Majority of authors acknowledge that first type of the disease (ADPKD1) in comparison with the second (ADPKD2) has more severe clinical course. On the basis of clinical analysis of selected affected families the larger and larger emphasis has been put on the influence of such factors like: presence of arterial hypertension, especially role of RAA system, sex, diet, hyperlipoproteinemia, environmental factors, toxic and infectious agents. It seems that genetic analysis of the RAA system and ADPKD will partially explain differences in the clinical course of the disease in different families. Persons with DD genotype in RAA system have statistically significant, more severe clinical course in comparison with their relatives with DI or II genotype. Decidedly worse course of the disease is observed in patients with positive family history of arterial hypertension and in persons with increased blood pressure. Patients sex play a major role. Men have more severe renal manifestations, when in women symptoms and complications associated with liver cysts are more frequent than in men. Frequency of intracranial aneurysms (ICA) in the population of patients with ADPKD have been presented. CT, MRA and classical angiography are in order screening tests for detection of ICA, especially in persons with family history of their prevalence. Prevalence of liver cysts and selected clinical symptoms and complications associated with extrarenal manifestations have been discussed. Problems associated with infections of the urinary tract and cysts, their etiology, pathomechanisms and treatment have been presented. Ultrasonography seems to be the best diagnostic tool because of it's accessibility, high sensitivity and low cost. It is accepted, that presence of 3 cysts in both kidneys in ADPKD kindreds in significant for diagnosis. Modified Ravine's criteria for diagnosis of ADPKD have also been presented. Employment of modern diagnostic methods in combination with genetic analysis (especially linkage analysis) enable early diagnosis in persons who are at risk of ADPKD.