System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system

As an environmentally harmless and feasible alternate refrigerant, CO₂ has attracted worldwide attention, especially in the area of automobile air-conditioning (AAC). The thermal property of CO₂ and its trans-critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO₂ system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO₂ AAC system.     

Woodward’s synthesis of vitamin B<Subscript>12</Subscript>

The synthesis of this molecule was a landmark in organic synthesis. It involved the masterful control of shapes of molecules to create 9 chiral centres with known absolute and relative configurations. The concepts of absolute and induced asymmetric synthesis are here explained.     

Oral Insulin—Fact or Fiction?

Insulin is a major protein hormone secreted by the β-cells of the pancreas and is important for the control of diabetes. Insulin is usually administered to diabetic patients through subcutaneous injection. This mode of therapy has certain inherent disadvantages such as local pain, itching and insulin lipodystrophy around the injection site. Hence, pharmaceutical scientists have been trying to design an oral delivery system for insulin. Many challenges are associated with the oral delivery of insulin, relating to the physical and chemical stability of the hormone, and its absorption and metabolism in the human body. Here we discuss various strategies for the oral delivery of insulin that are being tried out, as well as methods used to improve the absorption of orally consumed insulin and to reduce its degradation by digestive enzymes. K Gowthamarajan is on the faculty of the Department of Pharmaceutics in JSS College of Pharmacy, Ootacamund. His research interests are in the area of designing drug delivery systems for peptides and proteins. He is currently involved in research on pharmaceutical applications of plant polysaccharides. Giriraj T Kulkarni is on the faculty of the Department of Pharmaceutics in JSS College of Pharmacy, Ootacamund. Currently, he is involved in research on pharmaceutical and biotechnological applications of plant polysaccharides. He has authored a book ‘Biotechnology and its Applications in Pharmacy’ for undergraduate and postgraduate students of pharmacy.     

STUDENTS’ WAYS OF REASONING ABOUT NONLINEAR FUNCTIONS IN GUESS-MY-RULE GAMES

There is a growing movement toward the introduction of algebra in early grades. This is supported by an increasing number of research studies that have reported success in getting young students to “do” mathematics considered beyond their reach. Yet, the consensus is that more research is needed to provide insights into the processes by which students make sense of algebraic ideas. In particular, more studies are needed on how nonlinear functions can be introduced in early grades. This article reports an algebra research strand that introduced seventh grade students to quadratic functions using Guess-My-Rule games. The article describes several instances of the students engaging successfully with ideas and forms of reasoning involving quadratic functions. The purpose is to contribute to the debate on the introduction of algebra in early grades by providing further evidence of young students’ ability to engage with algebraic ideas usually considered to be beyond their reach.     

Reaction time signatures of discriminative processes: Differential effects of stimulus similarity and incentive

In three experiments with pigeons, the similarity of unreinforced test stimuli to a reinforced stimulus and the frequency of reinforcement associated with a stimulus were varied. The stimulus on each trial was a small spot that appeared in different hues or, in Experiment 3, different forms. Differential response frequency and reaction time (RT) patterns emerged: Changes in similarity affected the percentage of stimuli responded to but left the shape of RT distributions about the same, whereas changes in reinforcement shifted RT distributions but had little effect on the percentage of responses. When the similarity and reinforcement variables were applied to the same stimuli (Experiment 2), their effects were largely independent. A generalization procedure (Experiment 3) replicated the similarity effects of the initial discrimination procedure. The RT distributions were modeled by a diffusion process, and implications for a memory-instance model were suggested.     

The relationships among sex,gender identity factors,and career-decision-situation-specified personality traits

The present study revealed that gender identity involved the integration of various gender identity factors as suggested by Spence (1993) and that career-decision-situation-specified personality variables could be classified into higher order personality trait dimensions as suggested by Tellegen (1985). The results also indicate that the pattern of the relationships found in this study among masculine personality traits, feminine personality traits, and careerdecision-situation-specified personality variables reflecting higher-order personality trait dimensions of Tellegen’s (1985) model was similar to that of the relationships among masculine personality traits, feminine personality traits, and general personality traits reflecting higher-order personality trait dimensions in Lubinsky, Tellegen, and Butcher’s (1981, 1983) studies. Multiple regression analyses showed that the addition of a gender identity role attitude factor and a gender identity behavioral interest factor to sex and a gender identity personality trait factor did not improve significantly the prediction of the career-decision-situation-specified personality variables.     

Treatment and follow-up of children with transient congenital hypothyroidism

Objective: To study the clinical therapy and prognosis in children with transient congenital hypothyroidism (CH).Methods: Fifty-seven children with CH diagnosed after neonatal screening were treated with low-dosage levothyroxine (L-T4).Follow-up evaluation included the determination of TT3, TT4 and TSH serum levels and the assessment of thyroid gland morphology, bone age, growth development and development quotients (DQ). A full check-up was performed at age 2, when the affected children first discontinued the L-T4 treatment for 1 month, and one year later. Development quotients were compared (16.25±3.87) μg/d. Mean duration of therapy was (28.09±9.56) months. No significant difference was found between study group and control group in the DQ test (average score (106.58± 14.40) vs (102.4±8.6), P＞0.05) and 96.49% of the CH children achieved a test score above 85. Bone age, 99mTc scans and ultrasonographic findings were all normal, and evaluation of physical development was normal too, as were the serum levels of TT3, TT4 and TSH after one year of follow-up. Conclusion: A L-T4 dosage of and physical development at age 2. So it is possible for CH children to stop taking medicine if their laboratory findings and physical development are all normal after regular treatment and 2～3 years of follow-up.     

Disruption of latent inhibition by interpolation of task-irrelevant stimulation between preexposure and conditioning

Latent inhibition refers to attenuated responding to a conditioned stimulus (CS) that was repeatedly presented without reinforcement prior to the CS-unconditioned stimulus (US) pairings. Using water-deprived rats as subjects, we observed that interpolating task-irrelevant stimulation between the preexposure and conditioning phases of a latent inhibition procedure attenuated latent inhibition (Experiments 1A, 1B, and 2). Apparently, interpolated stimulation segments the preexposure and conditioning treatments into two separate experiences, much in the same way that a change of context would. Consistent with this view, the interpolated stimulation did not disrupt latent inhibition if it was also presented during both preexposure and conditioning (Experiment 3). We view these results as analogous to those of Escobar, Arcediano, and Miller (2003), who suggested that the difficulty in observing latent inhibition in human adults is related to the segmentation between preexposure and conditioning caused by the usual interpolation of instructions in preparations with humans.     

Defining Early Number Sense: A participatory Australian study

Recent publications in Australia focus on “number sense” as an important component of mathematics instruction. The current study attempted to tap into local expert knowledge in the area of early mathematics in an effort to establish a consensus on which skills reflect the number sense typically acquired by school entry. A modified Delphi procedure was employed whereby participants were asked to indicate their level of agreement with a variety of skills as indicators of number sense in young children. The study raised questions about the efficacy of this type of participatory research when used in relation to an ill‐defined construct. It also revealed a lack of consensus among the group of academics who agreed to participate in the study.