Number Of Successful Attempts Research Articles

Exploring relevant parameters and investigating their reproducibility of task-oriented unimanual strength measurement in children with unilateral cerebral palsy

Purpose To explore relevant parameters and investigate their test-retest reliability within the scope of the push button task of the Task-oriented Arm-hAnd Capacity (TAAC) measured in children with unilateral Cerebral Palsy (CP). Methods 118 children diagnosed with unilateral CP, aged between 6 and 18 years, participated in this study. Thetest–retest reliability of the force generated during the push button task of the TAAC was investigated using an intraclass correlation (ICC) two-way random model with absolute agreement. The ICCs were calculated across the whole age group and for two separate age subgroups (6–12 and 13–18 years). Results Test-retest reliability of the parameters “mean peak force of all attempts”, “overshoot of force”, “number of successful attempts” and “time to complete four successful attempts” were moderate to good (ICC range 0.667–0.865; 0.721–0.908; 0.733–0.817, respectively). Conclusions The results showed moderate to good test-retest reliability for all parameters. The parameters “mean peak force” and “number of successful attempts” are the most relevant parameters, as these parameters are task-specific and the most functional for clinical practice. Implications for Rehabilitation Clinical relevant information about the use of task-oriented strength during the performance of daily activity has been added to strength measurements in children with Cerebral Palsy. The Task-oriented Arm-hAnd Capacity instrument is a reliable, objective and simple instrument to measure task-oriented strength during daily activity and is ready for use in a clinical setting. The Task-oriented Arm-hAnd Capacity instrument is both a capacity and performance-based test. The measurement with the push button task showed moderate to good test-retest reliability.

Pattern Recognition: Age-Specific Features of Fundamental Movement Skills Formation in Elementary School Students

The purpose of the study was to determine the age-specific features of fundamental movement skills formation in elementary school students.
 Materials and methods. The study participants were boys aged 7 to 10 (24 boys aged 7; 28 boys aged 8; 35 boys aged 9; 36 boys aged 10). The children and their parents or legal guardians were fully informed about all the special aspects of the study and all the parents or legal guardians gave their consent thereto. The study protocol was approved by the Ethics Committee of the University. 
 The features of teaching 7–10-year-old boys to throw a ball at a vertical target were investigated. The proficiency level in throwing exercises in class was assessed using an alternative method (“performed”, “failed”), the probability of the exercise performance was calculated (p = n/m, where n is the number of successful attempts, m is the total number of attempts). A method of algorithmic instructions was used in teaching boys aged 7 to 10. The study materials were processed by IBM SPSS 20 statistical analysis software. A discriminant analysis was conducted. 
 Results. It was established that the first canonical function explains 64.5% of the variation in results, while the second one does 34.4%, which indicates their high informativity (r1 = 0.762; r2 = 0.652). The materials of the canonical function analysis show the statistical significance of the first and second canonical functions (λ1 = 0.236; р1 = 0.001; λ2 = 0.5633; р2 = 0.001). The first and second functions have a high discriminative ability and value in interpretation with respect to the general population. 
 Conclusions. The discriminant analysis made it possible to determine the age-specific features of throwing skills formation in boys aged 7 to 10; answer the questions to which extent the differences in the effectiveness of skills formation in boys aged 7 to 10 are significant; which motor tasks are the most specific to boys aged 7, 8, 9, 10; which class an object belongs to based on the values of discriminant variables. 
 It was established that the level of proficiency in exercise 4 “Throwing a ball forward-upward standing with the left side to the throwing direction” has the greatest effect on the process of throwing movement skills formation in boys aged 7 to 10. For boys aged 8 to 10, such an exercise is “Throwing a ball forward-upward standing feet apart”, and for boys aged 9 to 10, such an exercise is “Throwing a ball at a target 3 m away”.

Construct Validity of a Task-Oriented Unimanual Strength Measurement in Children with Unilateral Cerebral Palsy

Aim: Investigate aspects of construct validity of parameters “mean peak force” and “number of successful attempts” of the press button task using the Task-oriented Arm-hAnd Capacity (TAAC) in children with unilateral cerebral palsy (CP) by comparing them to outcomes of comparative measures using Consensus-based Standards for the selection of health Measurement INstruments guidelines. Methods: 118 children with unilateral CP (mean age 1 year 2 months, standard deviation 3 year 5 months) were included. Fourteen a priori hypotheses were formulated for each parameter of the TAAC. Strength and direction of the relationship between the TAAC and comparative measures were investigated by calculating Pearson correlation coefficients. Results: For the parameter “mean peak force” 8/14 (57%) hypotheses could be supported. For the parameter “number of successful attempts” 13/14 (93%) hypotheses could be supported. Conclusion: The hypothesized construct of the parameter “mean peak force” is only partially in line with our idea about the potential relationship of the compared constructs. The relationship needs to be reconsidered to some extent. The hypothesized construct of the parameter “number of successful attempts” is in line with our idea about the potential relationship of the compared constructs and can be considered to have good validity compared to the other measures. Thus, the construct of this parameter adds new and meaningful information as an outcome measure for functional strength measurements.

Comparison of 2D versus 3D in the Basic Single Incision Laparoscopy Training. A Randomized Controlled Trial.

Background: Single incision laparoscopic surgery is a technically challenging procedure. The use of 3D laparoscopy can potentially improve training results. The aim of the present study was to compare the short-term effects of the 2D vs 3D single incision laparoscopy training. Methods: Forty novices (25 males and 15 females) with no prior experience in single incision laparoscopic surgery participated in the study. The participants were randomized into 2D or 3D training mode. Results: Twenty participants were assigned to 2D and twenty to 3D training group. Time to finish the first task with the polypropylene ball transfer was significantly shorter in the 3D group with no difference in the total number of errors during the task (p=0.007). Overall number of attempts and number of successful attempts were similar between the groups while the number of errors was significantly higher in the 2D group during the needle grasping task (p=0.033). In the intracorporeal knot tying test the probability of completing the task was significantly higher in the 3D group (p=0.02). Conclusion: 3D training in basic single incision laparoscopy techniques seems to offer advantage over standard 2D training mode.

When Scents Help Me Remember My Password

Current authentication processes overwhelmingly rely on audiovisual data, comprising images, text or audio. However, the use of olfactory data (scents) has remained unexploited in the authentication process, notwithstanding their verified potential to act as cues for information recall. Accordingly, in this paper, a new authentication process is proposed in which olfactory media are used as cues in the login phase. To this end, PassSmell , a proof of concept authentication application, is developed in which words and olfactory media act as passwords and olfactory passwords, respectively. In order to evaluate the potential of PassSmell, two different versions were developed, namely one which was olfactory-enhanced and another which did not employ olfactory media. Forty-two participants were invited to take part in the experiment, evenly split into a control and experimental group. For assessment purposes, we recorded the time taken to logon as well as the number of failed/successful login attempts; we also asked users to complete a Quality of Experience (QoE) questionnaire. In terms of time taken, a significant difference was found between the experimental and the control groups, as determined by an independent sample t-test. Similar results were found with respect to average scores and the number of successful attempts. Regarding user QoE, having olfactory media with words influenced the users positively, emphasizing the potential of using this kind of authentication application in the future.

Discriminant Analysis: Impact of the Number of Repetitions on the Effectiveness of Teaching Boys Aged 7 Throwing a Small Ball

The aim of the study was to determine the impact of the number of repetitions on the effectiveness of teaching boys aged 7 throwing a small ball. Materials and methods. The study participants were 27 boys aged 7, who were randomly divided into three groups of 9 people each. The children and their parents were informed about all the features of the study and gave their consent to participate in the experiment. The study examined the impact of the number of repetitions on the effectiveness of teaching boys aged 7 throwing a small ball at a target. A pedagogical experiment studied the impact of 6, 12, and 18 repetitions with a 60-second rest interval on the increase in the level of proficiency in exercises of boys aged 7. In the first group, the boys repeated the task 6 times with a rest interval of 60 s, in the second group – 12 times with a rest interval of 60 s, in the third group 18 times with a rest interval of 60 s. When teaching throwing exercises during the class, the study assessed the level of proficiency by the alternative method (“performed”, “failed”) and calculated the probability of exercise performance (p = n/m, where n is the number of successful attempts, m is the total number of attempts). In teaching boys aged 7, the method of algorithmic instructions was used. The next exercise started after three successful attempts. Throwing a ball at a vertical target was taught. The study materials were processed by the IBM SPSS 20 statistical analysis software. During discriminant analysis, a prognostic model for group membership was created. Results. Discriminant analysis made it possible to determine the impact of the number of repetitions on the effectiveness of developing the skills of throwing a small ball at a target; to answer the question as to how significantly the modes of repetition differ by the effectiveness of motor skills development, to which class the object belongs based on the values of discriminant variables. Conclusions. Based on the analysis of group centroids, it was found that 12 repetitions of the exercise (6 sets 2 time each with a rest interval of 60 s) significantly influence the increase in the level of proficiency in physical education classes. The results of group classification show that 94.4% of the original grouped observations were classified correctly.

Pattern Recognition: Impact of Exercises Modes on Developing a Small Ball Throwing Skill in Boys Aged 8

The purpose of the study was to determine the impact of exercises modes on developing a small ball throwing skill in boys aged 8. 
 Materials and methods. The study participants were 21 boys aged 8, who were randomly divided into three groups of 7 people. The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment.
 The study examined the influence of the number of repetitions on the effectiveness of teaching boys aged 8 throwing a small ball at a target. A pedagogical experiment examined the influence of 6, 12, and 18 repetitions with a 60-second rest interval on the increase in the level of proficiency in exercises of boys aged 8. In the first group, the boys repeated the task 6 times with a rest interval of 60 s, in the second group – 12 times with a rest interval of 60 s, in the third group 18 times with a rest interval of 60 s. When teaching throwing exercises during the class, the study evaluated the level of proficiency by the alternative method (“performed”, “failed”) and calculated the probability of exercise performance (p = n/m, where n is the number of successful attempts, m is the total number of attempts). 
 In teaching boys aged 8, the method of algorithmic instructions was used. The next exercise started after three successful attempts. Throwing a ball at a vertical target was taught.
 The study materials were processed by the IBM SPSS 20 statistical analysis software. During discriminant analysis, a prognostic model for group membership was created. 
 Results. Discriminant analysis made it possible to determine the impact of the number of repetitions on the effectiveness of developing the skills of throwing a small ball at a target; answer the question as to how significantly the modes of repetitions differ by the effectiveness of motor skills development, what class the object belongs to based on the values of discriminant variables.
 Conclusions. Based on the analysis of group centroids, it was found that in boys aged 8, six repetitions of the exercise (6 sets one time with a rest interval of 60 s) significantly influence the increase in the level of proficiency in exercises during physical education lessons.
 The results of group classification show that 85.7% of the original grouped observations were classified correctly.

Impact of aerosol enclosure barrier to videolaryngoscopic oro-tracheal intubation: A pilot manikin study

Background: Personal protective equipment used for protection of healthcare workers in the combat against Severe Acute Respiratory Syndrome Coronavirus 2 pandemic is in limited supply worldwide at present – 2020. Use of barrier enclosure during endotracheal intubation can potentially act as a cost-effective adjunct to minimize risks of transmitting the infection to healthcare workers. However, there is concern that the enclosure itself will act as a barrier to the intubation procedure in the emergency settings. Objective: To evaluate the negative effect of barrier enclosure (an aerosol box) on the performance of video-assisted intubation in a manikin Methods: A total of 41 Emergency Department doctors from a local hospital were recruited to perform intubation in a manikin simulating normal and more difficult airways (Cormack-Lehane grades I and IIb) with and without the box. The primary outcome was time of successful intubation. The secondary outcomes were first-attempt success rate, number of successful attempts, need of adjuncts, dental injury and ease of intubation as perceived by the participants. Results: The aerosol box had no significant negative effect on the time of successful intubation (p = 0.630 (Grade I airway) and p = 0.436 (Grade IIb airway)), first-attempt success rate, number of successful attempts, need of adjuncts or dental injury. Participants subjectively reported extra yet minor challenges during intubation in the presence of the box. Conclusion: Within limits of the pilot study, the aerosol box had no statistical significant difference but an increasing trend of prolonged endotracheal intubation interval in the Grade IIb airway and negative impact on first-pass success, and could potentially be used to protect healthcare workers during the aerosol-generating intubation procedure.

Randomized Controlled Trial to Compare Baska® Mask versus ProSeal Laryngeal Mask Airway for General Anesthesia with Intermittent Positive Pressure Ventilation.

Introduction:A myriad of supraglottic airway devices (SADs) are developed over time to search the device that conforms to the anatomy of the human respiratory tract noninvasively, but these devices are associated with the risk of aspiration. Baska® mask (BM) is the latest addition to the family of SADs to circumvent the incidence of aspiration.Aims of Study:The aim of the study was to compare the sealing pressure and rapidity of the insertion of BM with ProSeal laryngeal mask (PLM) airway and the incidence of laryngopharyngeal morbidity between two devices.Materials and Methods:A randomized prospective open-label study was done on sixty adult patients of the age group of 18–60 years after approval from the institutional ethical committee and registration of trial in the Clinical Trials Registry. The patients were randomly divided into two groups: Group I (BM) where BM was inserted after the induction of general anesthesia and Group II (PLM) where PLM was inserted after induction. The airway sealing pressure in BM was calculated. The mean time of insertion of respective SAD and the number of successful attempts were also recorded in both groups. For analysis of continuous variables, independent sample Student's t-test was applied, and for categorical variables, Chi-square test was used. P < 0.05 was considered statistically significant.Results:The rate of successful attempts of insertion was comparable in both the groups. The mean insertion time was 14.25 ± 3.82 s in BM group and 22.01 ± 2.64 s in PLM group, which was statistically significant. The airway sealing pressure was 30.25 ± 3.34 cmH2O in BM group and 23.50 ± 4.05 cmH2O in PLM group, which was also statistically significant.Conclusion:BM has better ease of insertion with adequate sealing pressure as compared to PLM airway, thus reducing the chances of aspiration and offering its potential application in securing airway in emergency situations.

Role of routine use of ultrasonographic guidance for performing lumbar punctures

Purpose of studyUltrasound (US) for lumbar puncture has seen the most success in obese patients and in patients with difficult to palpate landmarks. We aimed to elucidate the advantage of...

Seabirds vary responses to supplemental food under dynamic natural prey availability and feeding aggregation composition

Abstract While foraging, a predator can feed solitarily or in a group. The net energy gain of joining a group is predicted to vary with prey patch quality, species-specific prey capture behavior, and the size and species composition of the predator group. In coastal Newfoundland, Canada, capelin (Mallotus villosus), a key forage fish, migrates inshore to spawn during the summer, resulting in a dramatic shift in prey availability. During July–August 2015–2017, we examined the numerical and behavioral responses of procellarid (Great Shearwater [Ardenna gravis], Sooty Shearwater [A. grisea], Northern Fulmar [Fulmarus glacialis]), and gull species (Herring Gull [Larus argentatus], Great Black-backed Gull [L. marinus]) to fish offal under varying capelin availability as well as flock size and composition using an at-sea experiment on the northeast Newfoundland coast. The experiment consisted of providing offal every 30 s (10-min experimental period), along with 10-min control periods before and after. We recorded the species-specific number of birds on the water, the number of birds simultaneously attempting to capture offal, and the number of successful attempts (“foraging success”). The number of birds on the water was lower during high capelin availability for all species, except for Northern Fulmar. The number of conspecifics simultaneously attempting to capture offal increased with the number of conspecifics on the water, but plateaued at different numbers (4–17) for most species. The species-specific proportion of successful attempts (i.e. foraging success) varied with flock size and composition (i.e. number of conspecifics, heterospecifics, species). Foraging success of Herring Gulls and fulmars were moderately affected by flock size and composition, suggesting that they may be dominant competitors. Findings suggest that seabirds rely more heavily on supplemental food sources, such as fisheries discards and offal, when natural prey availability declines, potentially resulting in a higher risk of by-catch during fisheries activities as forage fish stocks decline.

Obstacle detection using ultrasonic sensor for a mobile robot

There have been a number of successful attempts in designing obstacle avoiding robots. These works differ by selection of sensors, path mapping process and the algorithms applied to set the operational parameters. In this paper we present a los cost ultrasonic distance sensor for obstacle avoidance for mobile robot navigation. The system is implemented using microcontroller Arduino Uno, a Wi-Fi module, an Arduino motor shield driver which controls the robot through the geared dc motors. The system showed good performance under various lighting conditions. Experimental results with varied positions of obstacle show the flexibility of the robot to avoid it and have shown a decent performance in our laboratory. The robot is additionally ready to acknowledge victims before it, the sensing element system is extremely low-cost as a result of it solely uses one distance sensing element.

Graduating Fellows' Procedural Comfort Level With Pulmonary Critical Care Procedures.

Graduating fellows from pulmonary and critical care programs are expected to independently perform bronchoscopy and common medical procedures in the intensive care unit. Given variable exposure and learning opportunities at different training programs, little is known about how comfortable graduating fellows are with these procedures. A survey concerning the ACGME required procedures for pulmonary and critical care fellowship was sent to graduating fellows and program directors at all ACGME accredited subspecialty fellowship programs in pulmonary, critical care, and combined pulmonary critical care medicine. Critical care fellows performed the most intubations, paracenteses, arterial lines, central venous catheter insertions, and cardioversions, but did not perform as many bronchoscopy related procedures as the other subgroups. Pulmonary and combined pulmonary/critical care fellows performed and felt confident in most procedures. Program directors from all specialties agreed with the fellows overall about the procedural confidence gained during training. There also appeared to be a correlation between number of procedures performed and the confidence of the proceduralist. There appears to be a certain threshold number of successful completions to achieve confidence for independent practice for each surveyed procedure. There is a correlation between a fellow's procedural comfort with independent practice and the number of successful attempts by a graduating fellow. There are no universal guidelines that outline the appropriate number of successful attempts needed for independent practice, and our data strongly suggests that there is a threshold for each procedure across these three subspecialties.

Aptamers and Aptasensors as Novel Approach for Microbial Detection and Identification: An Appraisal.

Tremendous efforts through dedicated research have been made for the development of robust, point of care, portable, cost effective, sensitive and specific assays of microbial detection. Biosensing and nanotechnology offer novel strategies of designing state of the art devices and assay formats with enhanced sensitivity and all other desired features. Monoclonal antibodies have been in use as biorecognition elements for decades. However, recent studies have demonstrated superiority of aptamers to monoclonal antibodies in a number of applications. Many of the research groups have successfully utilized aptamers as capture probes in developing biosensors for microbial detection. The main objective of this review article is to present the reader with an overview of the recent advances made in the field of aptamers and aptasensors for the detection and identification of microbial agents. Our search for relevant information on current advances on aptamers and aptasensors has revealed that a number of successful attempts have been made in the last two decades for the selection of aptamers as well as their applications in aptasensors for microbial detection. Aptamers and aptasensors, although in their infancy, may find promising application in rapid, sensitive, point of care and cost effective microbial detection.

Effect of transplantation of adipose-derived multipotent mesenchymal stromal cells on the nervous tissue and behavioral responses in a mouse model of periventricular leukomalacia

The study of opportunities to use stem cells of different origins in the treatment and rehabilitation of patients with perinatal pathology of the central neural system (CNS) is important.The aim of our study was to evaluate the effects of transplantation of multipotent mesenchymal stromal cells (MMSСs) from adipose tissue in mice with experimental model of cerebral palsy – periventricular leukomalacia (PVL).Materials and methods. PVL was modeled by unilateral coagulation of common carotid artery in mice line FVB on sixth day after birth followed by exposure to hypoxia (6 % O2) with intraperitoneal injection of the endotoxin lipopolysaccharide 1 mg/kg. For transplantation we used MMSСs from adipose tissue of the 2nd passage derived from mice FVB-Cg-Tg(GFPU)5Nagy/J. Syngeneic transplantation of GFP-positive MMSСs suspension into seven-day-old (P7) animals with a model of perinatal brain damage was performed stereotactically into right hemisphere in 24 hours after PVL. Corticospinal function of the control animals and the mice with PVL was assessed by testing reaching and retrieval of food rewards.Results. After modeling PVL operated animals lagged in development, had less weight, height and disorders of static and kinetic reflex compared to non-operated control mice. Animals with PVL had lower rates of successful attempts at obtaining food: the percentage of successful attempts in control animals was 58 ± 3 % and in animals with PVL – 23 ± 4 %. In the group of animals with MMSСs transplantation after PVL modeling corticospinal function recovery was observed and the number of successful attempts was 43 ± 4 %.Conclusions. Syngeneic stereotactic transplantation of multipotent mesenchymal stromal cells from adipose tissue contributes to the restoration of behavioral responses in animals after PVL and improves cytoarchitectonics in the focus of brain damage

Coupling movement with imagery as a new perspective for motor imagery practice

BackgroundRecent data support the beneficial role of gesturing during mental practice. The present study examined whether coupling motor imagery (MI) with some movement sequences (dynamic imagery condition) impacted motor performance to a greater extent than performing MI while remaining motionless.MethodsA group of active high jumpers imagined their jump both with and without associated arm movement. Three outcome variables were measured: the number of successful attempts, the temporal congruence between MI and actual jump performance, and the technical quality of the jump.ResultsData revealed that dynamic imagery enhanced both MI quality and temporal congruence between MI and motor performance, and further improved the technical efficacy of the jump. Athletes also reported more vivid representation while coupling MI with actual movement.ConclusionsThese data support the hypothesis that performing dynamic imagery might contribute to enhance MI quality and efficacy, and sketch potentially fruitful new directions for MI practice.

Application of membranes to treat wastewater for its recycling and reuse: new considerations to reduce fouling and increase recovery up to 99 percent

The RO process is very attractive for providing high product quality through the removal of a number of contaminants like oil, detergents, organics, nitrates, ammonia, phosphates etc. However the main disadvantages of the modern RO techniques are connected with membrane fouling, concentrate flow and pretreatment that increase operational costs, complicate design and create problems of brine utilization. Often pretreatment costs even exceed reverse osmosis facilities costs. Now a number of successful attempts were undertaken to modify spiral wound membrane channels to limit fouling and scaling potential. As presented in a number of publications, elimination of the spacer mesh from the feed channels eliminates dead regions that provide scaling and fouling conditions whilst also reducing the risk of particle “trapping” and associated dramatic pressure increase. Introduction of a new “open channel” configuration offers a new perspectives to escape fouling and development of novel techniques to treat water with high fouling potential (high suspended matter, organics and supersaturated solutions). This novel concept of spiral wound module with an “open channel” design is developed, field-tested and introduced into practice. Fouling control is achieved due to the elimination of spacer and the implementation of an optimum hydraulic mode providing sufficient cross flow velocities, flushings and cleanings. The main principles of high recoveries, low maintenance and zero discharge are ensured by concentration of brine through re-circulation by 50−100 times by volume. Several examples of water treatment flow diagrams are presented to demonstrate of zero concentrate flow discharge. Coagulated suspended matter after membrane flushes is collected, sedimented and finally dewatered. The concentrated solution containing salts and impurities together with the wet sludge constitutes no more than 1 percent of initial water in part due to high supersaturation values due to the strong stability of calcium carbonate solutions.

Analysis and comparison of fast break in top level handball matches

The aim of this study was to describe an alternative approach in order to estimate the level of specific endurance (stamina) via video-analysis in handball athletes, which is required during the whole game. One thousand five hundred three (1503) attacks from 15 matches of 8 teams participating in the first division of the 2003 National Men’s Handball Championship were studied. For the analysis, all attacks were recorded and categorized based on the type of fast break. Furthermore, for each type of attack the outcome of the shot (goal, riposte, missed goal) and the offensive errors were recorded. All the fast break attempts (successful ones or not) were taken into consideration. The data analysis was conducted using Crosstabulation and chi-square tests. The results revealed that, during the first half, the 1st and 2nd wave were used in a percentage of 45,9% and 54,1%, respectively (p<0.05), although during the second half the percentage of each type was 63,3% and 36,7%, respectively (p<0.05). The third wave of fast break was not recorded. The number of successful attempts of fast break in the first half (77,1%) was greater than in the 2nd half (66,9%) (p<0.05). During the first half the frequency of the 1st wave (45,9%) was lower than that in the 2nd wave (54,1%) (p<0.05). However, during the second half the 1st wave’s frequency (63,3%) was greater compared to the 2nd wave’s (36,7%) (p<0.05). The form of analysis which was used to record, research and compare the frequency of appearance of fast break showed a reduction of fast break in the second half compared to the first half. There was also a significant difference between the two half times regarding the successful and unsuccessful fast breaks. The results may indicate some influence of training specificity and provide suggestions to coaches regarding the organisation of handball training drills that will possibly lead to an increase in explosive power.

Logarithmic growth in surface adsorption

A review is made of experimental data on surface adsorption of particles and polymers from water solutions, their analysis and interpretation in terms of general theoretical models of surface adsorption. A characteristic isotherm and kinetics is found and defined as logistic growth. The discussion is focused on literature indicating a possibility of describing logistic growth by using statistical (probabilistic) models based on the mean stay time of molecules on the surface. The statistical approach is further elaborated as follows: ligands arriving at a surface have a binary choice — to bind or to become reflected. Since the number of attempts to bind, n, will be high we can use the true mean of the binomial distribution to describe the reaction and write: S = n a; where S is the number of successful attempts and a is the probability of binding. The probability, a, will depend on the site density and on the sticking probability of the ligand at the binding site. Several experimental studies show that surface reactions have a nonlinear time- and concentration dependence and can be described by a Boltzmann factor of the form, I(1 − e −t τ ) ; where I is the flux of ligands to the surface and τ = stay-time. The exponential form indicates that the reactions are self-dependent, and a statistical model for description of such reactions will be of the form: S( t) = No(1 − 2 − αt ) (2 − βt ); where No is the number of molecules present in the system, α relates to the probability of positive cooperativity or t-dependent binding, and β relates to the probability of desorption.

Influence of the neuropeptide galanin on active avoidance in rats.

It was demonstrated in experiments on rats that the injection of the neuropeptide, galanin (200, 500, and 1000 ng), into the lateral cerebral ventricles induced a dose-dependent decrease in the number of successful attempts at avoidance in rats trained preliminarily to active avoidance by jumping. The preliminary administration of the cholinolytic, atropine (1 mg/kg, intraperitoneally), to the rats also caused an acceleration of the damping of the conditioned reflex and potentiated the indicated effect of galanin during the experiment. The use of the opioid antagonist, naloxone (1 mg/kg, intraperitoneally), did not exert an influence on the animals' behavior, but blocked the galanin-provoked acceleration of the extinction of the active avoidance habit. The intraperitoneal administration of a noncompetitive antagonist of excitatory amino acids, ketamine (10 mg/kg), did not influence the character of the animals' behavior nor the indicated effects of galanin. It was concluded that galanin possesses an amnestic action in the active avoidance test, and that this effect of the peptide is determined by the suppression of cholinergic and activation of opiatergic transmission in the central nervous system.