Present Experiment Attempts Research Articles

Lack of effects of acute exercise intensity on mnemonic discrimination.

The hippocampus is thought to support episodic memory by pattern separation, thereby supporting the ability to discriminate high similarity items. Past research evaluating whether acute exercise can improve mnemonic discrimination of high similarity items is mixed. The present experiment attempts to extend these prior mixed findings by evaluating the effects of multiple exercise intensities on hippocampal-dependent, mnemonic discrimination and memory performance. Fifty-seven young adults completed a three-condition (control, moderate-intensity, and vigorous-intensity), within-subjects crossover pretest-posttest comparison. We observed no effects of acute exercise on recognition memory or mnemonic discrimination. We discuss the implications of these null findings with the broader literature by discussing the complexity of this potential exercise-mnemonic discrimination relationship, including the unique role of exercise intensity, differences in the level of processing (e.g., conceptual vs. perceptual), and unique brain regions involved in mnemonic discrimination.

The influence of ultrasonic vibrations on material removal in the silicon wafer polishing using DDCAMRF: Experimental investigations and process optimization

The present experimental investigation attempts to understand and address the effect of ultrasonic vibrations on material removal in the polishing of silicon wafers (1 0 0). The requisite finishing experimentations were performed on an indigenously developed experimental arrangement of double-disc chemical assisted magnetorheological finishing (DDCAMRF) process with longitudinal vibrations. The MR fluid used in the experiments consists of a water-based suspension prepared by mixing suitable amounts of carbonyl iron particles (CIPs), abrasive particles, and additives or stabilizers. The prepared MR fluid uses both mechanics and chemistry to finish the silicon surface. Mechanics is mainly responsible for micro-scratching of silicon surface, which gets “softened” by hydration utilizing DI water in the MR fluid. In this study, the ‘response surface methodology (RSM)’ was chosen for designing the experiments to evaluate the significance of different process factors, namely polishing speed, abrasive concentration, and ultrasonic power on the material removal rate (MRR) in DDCAMRF process. The material removed from the wafer surface was measured using the precision digital weighing balance. It was observed that the MRR was found to increase with the increase in various process factors used. Further, analysis of variance (i.e., ANOVA) technique with a 95% confidence interval was performed to analyze the significant contribution of different process factors on MRR. The validation of developed model was done by performing experiments on random and optimized set of process factors. From, the statistical investigation it was discovered that ultrasonic power has highest contribution of 57.9% on MRR, followed by the polishing speed (13.3%), and abrasive concentration (12.5%). Furthermore, a genetic algorithm optimization tool was utilized to obtain optimum set of process parameters to maximize MRR.

Photo-catalytic studies of Mn and Fe tetraphenyl porphyrins in the degradation of Amido Black 10B dye with solar light

The free base tetraphenyl porphyrin (TPP) and its metalloporphyrins such as tetraphenylporphinatomanganese chloride (MnTPPCl), μ-Oxo-bis [tetraphenylporphinatomanganese [O-(MnTPP)2], tetraphenylporphinatoiron chloride (FeTPPCl) and μ-Oxo-bis [tetraphenylporphinatoiron] [O-(FeTPP)2] were synthesized in the laboratory and characterized by UV–visible, IR, Proton NMR and Fluorescence spectroscopy. Diffused reflectance spectroscopy revealed that all these compounds are low band gap semiconducting type materials. The photo-degradations of Amido Black 10B were performed to explore the photo-catalytic activity of these porphyrins using solar radiation at different pH conditions. In the present experiment attempts were made to use metal porphyrins without any supporting material, indirectly also to prove the photodynamic capabilities of these materials. It was revealed that pH plays an important role in the degradation of dye. The HPLC analysis of the product showed three components with same retention time irrespective of pH and ion chromatography indicated the mineralization of dye during degradation process. The results have shown the mineralization of the dye by redox reactions that are taking place at the respective groups present in the dye molecule. This eco-friendly remediation appears as a promising technique for degradation or mineralization of organic matter from contaminated water resources.

Performance of hybrid fibres on mechanical properties of self-compacting concrete at elevated temperature

Purpose The present experimental investigation attempts to study the behaviour of hybrid fibre-reinforced self-compacting concrete (HFSCC) subjected to elevated temperature. The purpose of this study is to find out the performance of hybrid fibres of 0.5 per cent by volume of concrete (out of which 75 per cent are steel fibres and 25 per cent, polypropylene fibres). Reinforced beams were casted and tested for the flexural load-carrying capacity, and comparisons were made with the load-carrying capacity of reinforced beams without the inclusion of fibres. Design/methodology/approach The study includes 60 concrete cubes of 150 mm and 60 beams of 150 × 150 × 1,100 mm reinforced with minimum tension reinforcement according to IS 456-2000. The specimens were subjected to elevated temperature from 100°C to 500°C with an interval of 100°C for 2 h. The residual compressive strength and the load-carrying capacity of beams for 5-mm deflection were measured. Parameters such as load at first crack, width and length of cracks developed on the beam during the application of load were also studied. Findings The result shows that for self-compacting concrete without fibres (SCCWOF), there is a gain in compressive strength between 200°C and 300°C, beyond which the strength decreases. For HFSCC, the gain in strength is between 300°C and 400°C, and thereafter the strength gets reduced. The load-carrying capacity of beams reduces with an increase in temperature. An increase in load-carrying capacity (up to 40.7 per cent) for HFSCC beams is observed when compared to SCCWOF beams at 500°C. Originality/value Better performance was observed with the usage of fibres when the specimens were subjected to elevated temperatures.

A cost-effective method to improve the performance of solar air heaters using discrete macro-encapsulated PCM capsules for drying applications

The present experimental work attempts to sustain the thermal response of the double-pass solar air heater system (DPSAHS) by the thermal lag of phase change material (PCM). At the same time, this analysis investigates the role of metallic macro-encapsulation on the heat storage and recovery from PCM integrated inside the DPASHS. The objectives are to investigate the influence of the geometry of encapsulation used for storage and to examine whether the discrete units allow faster charging and discharging of organic paraffin wax (PCM). In this work, an average encapsulate efficiency of 47.2% and 67% was obtained respectively for rectangular and cylindrical macro-encapsulates equipped DPSAHS. A performance comparison of DPSAHS with and without storage was presented. An overall cost analysis shows that with a small margin in constructional cost, operational time of DPSAHS was improved. The cost of heating 1 kg of hot air was 0.0074$. The overall work aims to support marginal and subsistent farmers to deal with improper drying during winter on which the potential sunshine hours are limited to 7 h/day at Calicut (11o32'N, 75o93'E) located in peninsular India.

Friction and Wear Characteristics of Indegenous ‘EPDM’ Rubber Under Dry Sliding Condition

Ethylene Propylene Diene Monomer (EPDM) rubber emerges as a dominant elastomeric compound for major engineering applications like automobiles, constructions, electric and electronic industries and many more. The major engineering properties of EPDM are its outstanding heat, ozone and weather resistance ability. The resistance to polar substances and steam are also good. EPDM rubber has a common use as seals in automobiles. In the presentwork friction and sliding wear behaviors of indigenously developed ethylene propylene diene monomer rubber (EPDM) of different hardness have been studied against steel counterpart in dry condition. Different hardness of EPDM have been achieved by adding different proportion (parts per hundred) of carbon black (CB) with the main ingredients of EPDM. Tribo-testing has been carried out in a multi tribo tester TR-25 (Ducom, India). Experiments have been conducted at a constant load of 25N with different speeds and times. The frictional force, coefficient of friction (COF), mass loss and wear of EPDM rubbers have been determined from the test data and concluded accordingly. Present experimental work attempts to highlight some important tribo-characteristics of EPDM rubber as well as to shed light on various possible areas of further research works including the study of worn surface morphology using scanning electron microscope (SEM).

Multi objective optimization of performance parameters of a single cylinder diesel engine with hydrogen as a dual fuel using pareto-based genetic algorithm

The present experimental investigation attempts to explore the performance characteristics of an existing single-cylinder four-stroke compression-ignition engine operated in dual-fuel mode with hydrogen as an alternative fuel. Experimental investigation was conceded with the engine being subjected to different loads at a predefined flow rate of hydrogen induction. A Timed Manifold Injection (TMI) system has been developed to vary the injection timing and the durations. The optimized timing for the injection of hydrogen was 100 CA after top dead center (ATDC). From the study it was observed that hydrogen with diesel results in increased brake thermal efficiency (BTHE) by 15.7% at 40% full load, volumetric efficiency (Vol. Eff.) by 78.5% at full load condition compared to baseline diesel operation. Hydrogen enrichment registered a maximum reduction of 41.4% in specific fuel consumption (SFC) of diesel at 20% full load. A pareto-optimal front was then obtained using nondominated sorting genetic algorithm (NSGA). Analysis of the front was done to identify the separate regions for Brake specific energy consumption (BSEC), Brake thermal efficiency (BTHE) and Volumetric efficiency (Vol. Eff.). Designed experiments were then conducted in these focused regions to verify the optimization results and to identify the region– specific characteristics of the process.

A Systematic Approach to Determine the Impact of Upsetting Ratio During Free Cold Forging Operation of Commercially Pure Aluminium in Dry Condition

Barrelling is an undesirable phenomenon during free upsetting process and develops due to interfacial friction of the billets and die halves. In the present experimental investigation attempts have been made to understand the effect of geometrical parameters on barrelling during cold upsetting of cylindrical billets of commercially pure alluminium in dry condition. Impact of height to diameter ratio has been discussed critically with an emphasis on the limiting value of the same. This study will be helpful in minimizing rejection rate of the finished parts and also be helpful in the selection of geometry of the metal pre forms.

A physiological and proteomic study of poplar leaves during ozone exposure combined with mild drought

The occurrence of high-ozone concentrations during drought episodes is common considering that they are partially caused by the same meteorological phenomena. It was suggested that mild drought could protect plants against ozone-induced damage by causing the closure of stomata and preventing the entry of ozone into the leaves. The present experiment attempts to create an overview of the changes in cellular processes in response to ozone, mild drought and a combined treatment based on the use of 2D-DiGE to compare the involved proteins, and a number of supporting analyses. Morphological symptoms were worst in the combined treatment, indicating a severe stress, but fewer proteins were differentially abundant in the combined treatment than for ozone alone. Stomatal conductance was slightly lowered in the combined treatment. Shifts in carbon metabolism indicated that the metabolism changed to accommodate for protective measures and changes in the abundance of proteins involved in redox protection indicated the presence of an oxidative stress. This study allowed identifying a set of proteins that changed similarly during ozone and drought stress, indicative of crosstalk in the molecular response of plants exposed to these stresses. The abundance of other key proteins changed only when the plants are exposed to specific conditions. Together this indicates the coexistence of generalized and specialized responses to different conditions.

Pressure drop and friction factor of steady and oscillating flows in open-cell porous media

Open-cell metal foams are often used in heat exchangers and absorption equipment because they exhibit large specific surface area and present tortuous coolant flow paths. However, published research works on the characteristics of fluid flow in metal foams are relatively scarce, especially for the flow oscillation condition. The present experimental investigation attempts to uncover the behavior of steady and oscillating flows through metal foams with a tetrakaidecahedron structure. In the experiments, steady flow was supplied by an auto-balance compressor and flow oscillation was provided by an oscillating flow generator. The pressure drop and velocity were measured by the differential pressure transducer and hot-wire sensor, respectively. The friction factor of steady flow in metal foam channel was analyzed through the permeability and inertia coefficient of the porous medium. The results show that flow resistance in the metal foams increases with increasing form coefficient and decreasing permeability. The empirical equation obtained by the present study indicates that the maximum friction factor of oscillating flow through the tested aluminum foams with specific structure is governed by the hydraulic ligament diameter-based kinetic Reynolds number and the dimensionless flow amplitude.

Effects of combined postischemic hypothermia and delayed N- tert-butyl- a-pheylnitrone (PBN) administration on histopathological and behavioral deficits associated with transient global ischemia in rats

Previous cerebral ischemia studies have reported the limitations of restricted periods of postischemic hypothermia in producing long-term neuroprotection. The present experiment attempts to determine whether delayed treatment with the free radical scavenger N- tert-butyl- a-phenylnitrone (PBN) is protective at 2 months following transient global forebrain ischemia, and whether additive effects can be observed when PBN is administered in combination with moderate hypothermia. For this aim rats were subjected to 10 min of two-vessel forebrain ischemia followed by (a) 3 h of postischemic normothermia (37°C); (b) 3 h of postischemic hypothermia (30°C); (c) normothermic procedures combined with delayed injections of PBN (100 mg/kg) on days 3, 5 and 7 post-insult; (d) postischemic hypothermia combined with delayed PBN treatment; or (e) sham procedures. Outcome measures included cognitive behavioral testing and quantitative histopathological analysis at 2 months. Postischemic PBN injections induced a systemic hypothermia (1.5°C–2.0°C) that lasted for 2–2.5 h. Water maze testing revealed significant performance deficits relative to shams in the normothermic ischemic group, with the postischemic hypothermia and PBN groups showing intermediate values. A significant attenuation of cognitive deficits was observed in the animal group receiving the combination postischemic hypothermia and delayed PBN treatment. Quantitative CA1 hippocampal cell counts indicated that each of the ischemia groups exhibited significantly fewer viable CA1 neurons compared to sham controls. However, in rats receiving either delayed PBN treatment or 3 h of postischemic hypothermia, significant sparing of CA1 neurons relative to the normothermic ischemia group was observed. These data indicate that hypothermia combined with PBN treatment provides long-term cognitive improvement compared to nontreatment groups. PBN-induced mild hypothermia could contribute to the neuroprotective effects of this pharmacological strategy.

Characterization of adenoviral gene expression in spinal cord after remote vector delivery.

Recent work has established that the remote injection of attenuated adenoviral vectors may result in central nervous system (CNS) gene expression. These studies suggest that virus passes through peripheral nerves into the CNS. The present experiment attempts to characterize this phenomenon systematically. Spinal cord cells staining for the reporter gene beta-galactosidase were histologically quantified after microinjection of the viral vector Ad5RSVntLacZ into rat footpad, muscle, or sciatic nerve. The effects of injection location, titer, and time, as well as nerve crush and dexamethasone, were examined. Sciatic nerve viral vector injection results in significantly higher CNS uptake than intramuscular and subcutaneous injections (P < 0.05). Nerve crush injury caused a time-dependent reduction in spinal cord gene uptake after sciatic nerve adenoviral injection (P < 0.05). Neuronal staining reaches its peak at 6 days after injection (P < 0.002). Peripheral nerve delivery to the CNS increases with augmented titers (P < 0.03). Finally, gene expression is augmented by administration of dexamethasone (P < 0.0001). Remote adenoviral vector injection represents a potential method for spinal cord gene therapy that avoids any manipulation of CNS tissue.

Gaze discrimination is unimpaired in schizophrenia

Interpersonal communication is largely dependent on interpretation of facial expression and emotion. Difficulties in face processing, and more specifically in gaze discrimination, have been described in schizophrenic patients. According to Baron-Cohen (Mindblindness. M.I.T. Press, Cambridge, MA, 1995), gaze discrimination relies on the functioning of a specific cognitive module, the Eye Direction Detector (EDD). It has been proposed [Rosse et al. (1994) Gaze discrimination in patients with schizophrenia: preliminary report. American Journal of Psychiatry 151, 919–921] that an impairment in gaze discrimination is present in schizophrenia, and plays a fundamental role in inducing the paranoid symptoms reported by many patients. However, in the previous studies, gaze direction detection and interpretation of gaze have never been completely dissociated. The present experiment attempts to test the schizophrenics' skill in a simple gaze direction detection task. A series of photographic portraits of models looking at different directions have been presented to 22 schizophrenic patients and 36 control subjects. For each portrait subjects were asked to determine whether gaze was directed to the right or to the left by pressing a keyboard key. A forced choice paradigm was used. No differences were reported between schizophrenic patients and control subjects. That is, in the present paradigm, schizophrenic patients did not show any specific impairment in detecting the direction of gaze of the portraits. The results are discussed according to the notion that a dissociation is present in schizophrenia between implicit and explicit processes. The present case illustrates how the more automatic elementary functions, such as the detection of gaze direction, may be spared in schizophrenic patients, whereas explicit cognitive functions are likely more affected.

Further investigations of phonological factors in phonetic perception

Recent investigation has demonstrated an influence of phonological permissibility on the identification of ambiguous phonemes (Wannemacher and Sawusch, 1989). Depending on the speed of response, early phonologically biasing information shifted classification of an ambiguous target. The fast responses showed the greatest influence of permissibility, while at longer latencies this biasing effect decreased. Possible explanations for this pattern of results include tacit use of rule-governed phonological knowledge and the operation of feedback from an interactive system involving lexical access. The present experiment attempts to distinguish these two proposals by examining the time course of permissibility effects. The same basic paradigm as used in the previous experiment was employed here, but with the phonologically biasing information occurring after an amibiguous target phoneme. The results of the late and early biasing conditions will be compared in order to determine the nature of the influence of phonological permissibility on phonetic coding. [Work supported by NIDCD Grant DC00219 to SUNY at Buffalo.]

Influencing the "Shape" of Resistance: An Experimental Exploration of Paradoxical Directives and Psychological Reactance

The deliberate employment of defiance-based paradoxical directives in psychotherapy has frequently been related to benefits derivable from accepting and utilizing client resistance toward change. The social-psychological concept of reactance, based on the need for autonomy with the consequent tendency to resist another person's directives, is here postulated as the best explanation for this resistance. The present experiment attempts, analogously, to investigate certain hypotheses about reactance arousal in a paradoxical intervention. Participating in this study were 148 undergraduates, 72 male and 76 female. These students were confronted with an anxiety-laden situation involving an extremely tempting opportunity to cheat. Asked to assume they had succumbed to this temptation, they were instructed to decide among nine alternatives for dealing with their potentially hazardous behavior and then asked to redecide after exposure to a strongly authoritative (i.e., reactance-arousing) recommendation, presented...

SPATIO‐TEMPORAL INTEGRATION IN READING TACHISTOSCOPICALLY PRESENTED WORDS

ABSTRACTIt has been suggested that there is a visual encoding of a verbal stimulus which outlasts the duration of the icon. An attempt is made to determine what the characteristics of such an encoded representation are. The present experiment attempts to demonstrate that spatio‐temporal information is utilized in the encoding processes necessary for word recognition. The letters of words are presented over successive tachistoscopic exposures which subjects are instructed to either integrate in terms of the temporal order of input or in terms of the spatial location. The central finding indicates that word recognition latencies are significantly elevated by the existence of an interpretation of the stimulus resulting from integration of the uninstructed form. The findings offer a demonstration of a stable memory matrix capable of representing alphabetic characters in terms of identity as well as spatial locus and temporal order of input.

An Investigation of the Relationships between Problem Solving Strategies, Representation and Memory

There has been considerable debate in recent years about the status of “imagery” in problem solving. The present experiment attempts to show that while subjects may employ representational strategies when they first encounter a class of problems, they abandon such strategies as they gain experience with the problems. It does this by asking subjects to answer unexpected questions which are based upon the information which they have just used to solve a problem. The hypothesis, which is supported by the results, is that increasing experience with problems will be paralleled by a decreasing ability to answer unexpected questions. The experiment also shows that such effects are not attributable to a build-up in proactive interference.

白血病の亜鉛代謝に関する研究

With object of studying Zinc metabolism in leukemic patients the Zinc score in granulocytes was estimated by Mc Nary's method in Part 1. In the present experiment attempts were made to determine by atomic absorpiton spectrophotometry the serum Zinc content what is thought to be closely associated with Zinc metabolism, and the study was also made on changes in the Zinc levels according to types of diseases and to the results of treatment. Also Zinc contents in the urine and organs were estimated, though the cases studied were only a few innumber. The relationship between Zinc score and serum protein picture was also investigated.Materials and MethodsThe subjects were all the patients admitted to the Second Department of Internal Medicine, Okayama University. They consisted of 9 cases of acute myelogenous leukemia (AML), 9 cases of acute lymphocytic leukemia (ALL), 4 cases of monocytic leukemia (MoL), 15 cases of chronic myelogenous leukemia (CML), 2 cases of chronic lymphocytic leukemia (CLL), and I case of erythrocytic leukemia (EL), to the total of 40 cases, as well as 6 cases of malignant lymphoma as related disease. For the control group 12 adult males and 15 adult females tothe total of 27 healthy persons were selected.Results and Conclusion1) It has been found that serum Zinc levels in healthy persons proves to be 134±12.2mcg/dl in males and 113.8±16.4mcg/dl in females, average being 119.2±16.5mcg/dl.2) The serum Zinc levels according to types of leukemia prove to be 106.9±31mcg/dlin AML; 93.±32mcg/dl in ALL, 81.7mcg/dl in Mol, 111.1±31mcg/dl in CML, 98.0±18mcg/dl in GLL, and 62.5mcg/dl in EL.3) The serum Zinc score in leukemic patients is found to be low before treatment and at the time of aggravation in ALL and CLL, but it tends to recover to its normal level as the condition improves in both ALL and CLL.4) There can be observed no significant correlations among the serum Zinc content, Zinc score of granulocytes, and alkaline phosphatase of neutrophils of the same leukemic individual.5) There are also no significant correlations among the serum Zinc content, serum protein contents and their fractions in the same leukemic patient.6) In studying 65Zn-uptake by each protein fraction of leukemic patient serum after labeling it in vitro with 65Zn, it has been demonstrated that the uptake by albumin is 52.7%, by α1-globulin 15.53%, by α2-globulin 18.62%, by β-globulin 9.19% and by γ-globulin to be 3.62%, indicating that the albumin fraction has taken up the major portion of 65Zn, which is followed by the uptake of α2-globulin and α1-globulin.7) In the study of absorption test and quantitative analysis of urinary Zinc contents after the administration of Zinc difference from the results with normal healthy control.8) In estimating Zinc contents of erythrocytes, and leukocytes as well as Zinc contents in the liver, spleen, bone marrow and kidneys there can be observed no significant difference from the results with the normal control group.9) It is assumed that disturbance of Zinc absorption and acceleration of its excretion, and the decrease in serum protein and albumin fractions are not mainly responsible for the mechanism of decreasing Zinc content in the serum of leukemic patient, but rather it is dependent upon other complex factors.

SHAPE AND SIZE DISCRIMINATION IN OCTOPUS: THE EFFECTS OF PRETRAINING ALONG DIFFERENT DIMENSIONS.

Abstract : It has been suggested that discrimination learning involves two processes. Animals learn first to switch-in a stimulus-analysing mechanism that yields different outputs for the discriminanda and, secondly, they learn to attach the correct responses to those outputs. This hypothesis predicts that training an animal to respond to one cue should make it more difficult for it to learn to respond to a second type of cue. Previous experiments have shown that when animals trained to respond to one cue are subsequently presented with a problem that can be solved in terms of that cue or in terms of a second cue they do learn something about the second cue. The crucial question for the model proposed is not whether, under these conditions, animals learn something about a second cue, but whether they learn as much as animals not previously trained to respond to the first cue. The present experiment attempts to answer this question. Sixteen octopuses were trained and tested in three stages. In Stage I, one group learned a size discrimination, the other group learned a shape discrimination. In Stage II, all animals learned a new problem. This problem was the same for both groups and could be solved in terms of shape or size differences or both. In Stage III, transfer tests were given with the same shapes as those used in Stage II but no differences in size were present. (Author)

CIRCULATING STEM CELLS: VARIATION WITH DURATION OF PARTIAL BODY X-IRRADIATION.

LEUCOCYTE depression is often produced by localized radiation therapy. This frequently appears inordinate for the amount of bone marrow within the radiated field. A possible explanation for this leucopsenia is that during a course of radiation therapy (usually given in daily doses for a number of weeks) a large number of circulating stem cells1−6 enter the radiated field, are destroyed, and thus a leucocyte depression is produced. I have attempted to test this hypothesis in previous experiments7,8 by subjecting two groups of mice to partial body irradiation. Both groups received the same total dose; however, one group was radiated for 2–3 min while the other was exposed for 100–120 min. If the hypothesis is correct, then the mice exposed for the longer duration should develop a more profound and prolonged leucopaenia. This is what was observed. The present experiment attempts, more directly, to observe the effects of the duration of partial body irradiation on the number of circulating stem cells to see whether these changes in the leucocyte levels reflect changes in stem cells.