Mathematical modeling of thin layer solar drying of tomato slices

Thin layer drying of tomato slices was evaluated using a laboratory solar dryer.  The experimental moisture ratios of the samples were fitted to nine drying models.  The drying experiments were carried out on tomato slices with thicknesses of 3, 5 and 7 mm at the air velocities of 0.5 and 1 m s-1.  The effect of drying thickness and air velocity on the drying time was evaluated.  The mathematical models were tested with the drying behavior of tomato slices in the laboratory solar dryer.  The coefficients of the models were determined by multiple regression method in three spaces (solar dryer, shadow, open sun drying) to find out the most suitable moisture ratio model.  The Page model was found as the best model based on statistical parameters of R2, RMSE and χ2.  The Page model is applicable to predict moisture content of tomato slices during solar drying of tomato slices.   Keywords: pedal operated thresher, thresher, thresher drive linkage, physiological workloa

Subcloning, purification and characterization of the GLY1 gene product of Saccharomyces cerevisiae

grantor: University of TorontoIn Saccharomyces cerevisiae the inactivation of both the cytosolic and mitochondrial isozymes of serine hydroxymethyltransferase, as well as a third gene, designated GLY1, are necessary to yield glycine auxotrophs. The functional characterization of the GLY1 gene was approached by assaying for threonine aldolase activity catalyzing the conversion of threonine to glycine and acetaldehyde using the GLY1 enzyme purified on a nickel column. In the pursuit of showing that the expression of the GLY1 gene might be up-regulated by threonine and down-regulated by glycine, a yeast shuttle vector in which the promoter and the 5\sp\prime coding region of the GLY1 gene were fused to a reporter gene (Lac Z) was used to transform the yeast strain YM 22 to leucine prototrophy. The transformed yeast cells were grown in the presence and absence of L-threonine in minimal medium. A $\beta$-galactosidase assay was done on the crude extracts. We next examined the hypothesis that GLY1 may be part of the "glyoxylate anaplerotic pathway" coding for an enzyme with a glyoxylate aminotransferase activity. To characterize the possible aminotransferase activity of the GLY1 protein, a yeast shuttle vector containing the entire GLY1 gene sequence was used to transform the ser1 yeast strain to uracil prototrophy. (Abstract shortened by UMI.)M.Sc

Characterization of the role of domains and subdomains of aggrecan in post-translational processing and secretion

Aggrecan is the major proteoglycan in the articular cartilage. This molecule is crucial to the chondroskeletal morphogenesis during development and it is also important in the proper functioning of articular cartilage by providing hydrated gel structures (via its interaction with hyaluronic acid and link protein) which endow the cartilage with load bearing properties. Aggrecan is a multimodular molecule expressed by chondrocytes. To determine the role of each aggrecan domain in its post-translational modification and secretion, we generated a number of recombinant DNA constructs bearing various aggrecan domains individually or in combinations with other domains. We observed that G1 and G2 domains inhibited product secretion and GAG chain attachment whereas, G3 domain promoted secretion and GAG chain attachment. Knowing that G1 and G2 inhibited secretion, we set to identify which region of G1 and G2 shared the inhibition of secretion properties. Utilizing recombinant genes, we demonstrated that the first tandem repeats of G1 and G2 inhibited product secretion if expressed alone or in combinations with other domains and subdomains. We next tried to isolate the amino acid residues in the first tandem repeat of G1 involved in the inhibition of secretion by mutagenesis experiments. C-terminal mutagenesis of the first tandem repeat of G1 did not promote the secretion, however, N-terminal mutagenesis (point mutations and deletions) gave rise to enhancement of secretion. We noticed that there were four N terminal residues, FHYR, which seemed to be important in inhibition of secretion, however, we next realized that these four residues were part of a stretch of 55 amino acids required for the inhibitory property. Yeast two-hybrid analyses also indicated that TR1 of G1 is interacting with ER-bound chaperones.Ph.D

The Effect of Tetrahydrocannabinol on Acetylcholinesterase Enzyme Activity and Anxiety-Like Behaviors in Laboratory Rat

Background and Objectives: Tetrahydrocannabinol (THC) is a psychoactive substance that affects the central nervous system. Acetylcholinesterase enzyme, as one of the enzymes of central and peripheral nervous system, plays a role in the sympathetic and parasympathetic function. This enzyme transmits neural messages through hydrolysis of acetylcholine in the cholinergic synapses and is of great importance in memory and learning. In this study, the effect of THC was investigated on the cholinergic system in rat behaviors. &nbsp; Methods: In this experimental study, 10 adult male rats were used. First, the rats were anesthetized, then, two cannulas were placed in the ventricle using stereotaxic apparatus and THC was injected. The activity of the acetylcholinesterase enzyme was measured, and plus maze test was used to assess the anxiety behavior. Data were analyzed using t-student test. &nbsp; Results: In this study, THC reduced the activity of acetylcholinesterase enzyme, indicating memory impairment. Moreover, the percentage of time spent in the open arm and the percentage of the number of entries into the open arm increased (p<0.05), and corticosterone levels increased, which both indicated an increase in anxiety. &nbsp; Conclusion: The results of this study showed that THC causes changes in memory and anxiety behaviors by impairing cholinesterase enzyme activity and neurotransmitter secretion. &nbsp

Status of National Scientific Journals in Databases: The Case of Agriculture and Natural Resources Journals

Results of scientific research are diffused by scientific journals; therefore these journals have a significant role in development of scientific disciplines and are considered as a criterion for their growth. Paying attention to quality and quantity of these journals is a base for planning of academic disciplines promotion. This research was conducted to investigate the quantity of agriculture and natural resources journals in Iran, their indexing status in various databases, and ranking disciplines and publishers of these journals by applying a descriptive – comparative research methodology. Finally, based on the research findings, some applicable recommendations for upgrading the national scientifi journals as well as in agriculture and natural resources fields have been presented in this paper

Buckling and Vibration Analysis of Tapered Circular Nano Plate

In this paper, buckling and free vibration analysis of a circular tapered nanoplate subjected to in-plane forces were studied. The linear variation of the plate thickness was considered in radial direction. Nonlocal elasticity theory was employed to capture size-dependent effects. The Raleigh-Ritz method and differential transform method were utilized to obtain the frequency equations for simply supported and clamped boundary conditions. To verify the accuracy of the Ritz method, the differential transform method (DTM) was also used to drive the size-dependent natural frequencies of circular nanoplates. Both methods reported good results. The validity of solutions was performed by comparing the present results with those of the literature for both classical plate and nanoplate. The effects of nonlocal parameter, mode number, and taper parameter on the natural frequency were investigated. The results showed that increasing the taper parameter causes increasing of buckling load and natural frequencies, and its effects on the clamped boundary condition is more than the simply support

Population dynamics parameters of narrow-barred Spanish mackerel, Scomberomorus commerson (Lacèpéde, 1800), from commercial catch in the northern Persian Gulf

Population dynamics parameters of Scomberomorus commerson in Bushehr area waters of Iran were analyzed between October 2011 and September 2012. Fork length frequencies were collected from the gill net commercial catch. Von Bertalanffy growth function was used to estimate growth parameters K and L∞. Instantaneous total mortality rate (Z), instantaneous natural mortality rate (M) and the instantaneous fishing mortality rate (F) were also calculated. Resource status was evaluated by comparing estimates of the fishing mortality rate with target (Fopt) and limit (Flimit) biological reference points. FiSAT program was used to assess growth and mortality parameters. Based on the growth curve analysis, growth parameters were: K=0.5year−1 and L∞=148cm. Instantaneous total mortality was Z=0.97year−1. The estimate of M=0.56year−1 and F=0.41year−1, resulting in an exploitation rate (F/Z) of E=0.42year−1. Target and limit biological reference points were: Fopt=0.28year−1 and Flimit=0.37year−1. Size at capture at probabilities of 0.25 (L25), 0.5 (L0.5) and 0.75 (L0.75), were 46.3 cm, 55 cm and 60.2 cm respectively. Longevity (Tmax) was calculated as 3/K equal to 6 years. The exploitation rate (E) did not indicate overfishing; however, Fopt and Flimit rates were lower than fishing mortality (F), suggesting that overexploitation occurred. Growth parameters in the present study showed that the gillnet fishery catches of S. commerson that are of ages 1 or 2, which may not have reached maturity. Gillnet mesh size can be a factor why the catch is composed of mostly small, immature fish. Therefore, changes in mesh size and net size should be considered