It is necessary to review and evaluate the operation of the system and determine appropriate methods forests due to topographic conditions are significant operational activities, products, transportation, and the road making the destructive activities of the Forest as the most expensive. In this study, Economic Evaluation to be considered LTT-100A skidding system upward. After field operation and time study, using the regression model, the model is proposed to predict skidding time. Among the components of each cycle skidding in Zetor, moving with load and moving empty most of the time per cycle and in the form of delays, technical delays included the most time. The model predicted the skidding time Zetor have meaningful skidding distance and slope. hourly production rate of 12.5 cubic meters per hour and the cost of producing these systems is achieved 119, 795 rials per cubic meter. Because of the speed and its efficiency Zetor is low, thus in long intervals and in places where travel time is limited, use of this system is not recommended for skidding operations. But since the power of this machine is its high and rapid stabilization is done, the application of this system, is recommended to be combined with other systems.

The soil is a basic source and essential in forest that necessary to long- term process for formation. On other hand, one of the main soil management principles is long-term stability of its fertility. Heavy machinery mostly are used to exploitation of forests that them employing is caused serious soil destruction and damage. So that, soil compaction between two slop classes in effect of traffic steel tracked skidder LTT-100A has been studied. In this study, skidding of Parcel 10 and 11 A Serie 3 Soordar-Vatashan were selected. Soil sampling using by cylinder (cylinder 10 cm in length and internal diameter 5 cm) was determined from a depth of 0-10 cm due to the excessive influence of the horizon from set skidding operation. In order to collected data analysis from the study area, is used Spss software. The results showed that effect of slope variables and number of traffic is significant on the bulk density of soil in 99% level. Also, bulk density of soil increased when slop classes and number of steel tracked skidder was increased on the skid trail. On other hand, the moisture percentage decreased in skid trail with increasing traffic. As soil moisture decreased from 27.3% in control sample to 12.45% during traffic ten. Decreasing moisture is increase in 10-20% slope class. So, investigation of changes of soil physical characteristic show that soil compaction will increase with increasing slope direction and number of traffic.

In electric arc welding, the heat generated by the arc causes non-uniform expansion and contraction in the weld and surrounding areas. Uneven expansion and contraction and the resulting plastic deformation are the main sources of residual distortion and stress in welded structures. The distribution of residual stresses in a welded joint depends on factors such as heat input, arc welding speed, material properties, preheating, part thickness, groove geometry and welding execution schedule. In this research, a head to head joint is investigated by penetration welding with experimental methods and finite element simulation. Residual stresses are measured by the central hole drilling method and by converting the obtained data into residual stresses, the obtained results are used to verify the developed finite element model. In the finite element model, the non-coupled thermal-mechanical mode is used and the method of birth and death of the elements is used in the simulation of filler materials. In the simulation, the phase transformation process is considered and with the help of LTT filler introduced, the residual stresses in the single-pass welding show a 15% reduction and in the two-pass welding show a 17% reduction in the tensile residual stresses. By examining the effect of the arrangement and composition of the passes and the type of welding fillers, it was found that the combination of LTT electrode with 6010 electrode provides more favorable results for residual stresses. Regarding the effect of thickness change in the cross section of the samples, the output of the results of both numerical analysis software does not show significant changes.

In the following research the relationships between the positive psychological states (i.e. happiness) and the body immunology performance has been studied. Two inventories including Beck Depression Inventory and Onford Happiness Inventory (OHI) have been completed by 150 subjects. Based on the questionnaires, 15 subjects with the highest scores and 15 with the lowest scares on the OHI were selected. In order to determine the level of Lymphocyte Transformation Test (L TT) , and the percentage of CD3 + , CD4 + , CD8 + ,and CD56 + cells, the blood samples of the subjects were analyzed. Results supported the idea that the happiness subjects had significantly higher LTT level and CD 56% than non-happiness group.

In electric arc welding, the heat generated by the arc causes non-uniform expansion and contraction in the weld and surrounding areas. Uneven expansion and contraction and the resulting plastic deformation are the main sources of residual distortion and stress in welded structures. The distribution of residual stresses in a welded joint depends on factors such as heat input, arc welding speed, material properties, preheating, part thickness, groove geometry and welding execution schedule. In this research, a head to head joint is investigated by penetration welding with experimental methods and finite element simulation. Residual stresses are measured by the central hole drilling method and by converting the obtained data into residual stresses, the obtained results are used to verify the developed finite element model. In the finite element model, the non-coupled thermal-mechanical mode is used and the method of birth and death of the elements is used in the simulation of filler materials. In the simulation, the phase transformation process is considered and with the help of LTT filler introduced, the residual stresses in the single-pass welding show a 15% reduction in the tensile residual stresses. By examining the effect of misaligned welding on the specimens, the amount of residual stresses generated increases significantly.

Background: The informal abuse of a mixture of tomtom candies and Lacasera beverage, known as Lacatomtom (LTT), is a growing public health concern in Nigeria. Given the brain's high vulnerability to oxidative stress, this study evaluated the effects of oral LTT consumption on brain oxidative stress and antioxidant enzyme responses in Wistar rats. Methods: A total of 24 male Wistar rats were divided into four groups: control (distilled water), LTT, Lacasera, and Tomtom in water (TTW). Samples were orally administered once daily for 30 days, after which brain tissue was analyzed for malondialdehyde (MDA) and key antioxidants, including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and reduced glutathione (GSH) using standard methods. Results: The LTT consumption significantly elevated brain MDA levels, indicating increased lipid peroxidation and significant oxidative stress. Concurrently, it upregulated SOD, CAT, GSH, and GPX activity, suggesting a strong but ultimately insufficient compensatory antioxidant response. Lacasera alone also contributed to elevated MDA, with its aspartame content identified as a potential factor. The TTW mixture showed a milder oxidative stress profile. However, the complete LTT mixture induced the most pronounced oxidative stress, accompanied by the strongest compensatory antioxidant response, indicating synergistic neurotoxic effects. Conclusion: In conclusion, oral LTT consumption significantly induces brain oxidative stress in Wistar rats. The complete LTT mixture exhibits more pronounced neurotoxic effects than its individual components, highlighting a serious public health threat linked to its psychoactive properties and documented multi-organ toxicity.

Nowadays, with mechanization development, evaluation of machine productivity and calculation of average cost of skidding for each hour and each cubic meter is necessary to compare their efficiency. In this study, the mathematical model of production and cost of steel tracked skidder LTT-100A was studied in Tarbiat Modares University Experimental Forest (TMUF). Continuous time study was applied during skidding operation to record the time spent for each component of skidding. The obtained data was then analyzed using multivariable regression analysis to build the mathematical model of production. Results showed that skidding distance, skid trail slope and volume of logs at each cycle are significant variables influencing skidding time. The share of delay was 14.94 % of total time while 44% of delays time was identified as technical delay (unavoidable delay), personal and operational delay were recorded 33% and 21% percent, respectively. Skidder productivity regardless of delay time and effective time were calculated 5.84 m3/h and 4.98 m3/h, respectively. Total average cost of system was estimated 265678 RLS/h and 54330 RLS/m3, respectively (Rials= 50cent).

MTT assay is designed for spectrophotometric quantification of cell growth and viability without using the radiactive isotopes. The aim of this study is comparison of LTT and MTT as sensitive poliferation assays in immunodeficient patients. 20 immunodeficient and 20 healthy subjects were selected in this study. All of them had normal lymphocytes count, normal CD3 and negative DTH reaction to PPD, DT and candida. The immunodeficient patients regularly suffered from herpes, candida and staph abscess. The lymphocytes of immunodeficient control groups were treated with PHA as mitogen. The lymphocyte proliferation was evaluated by MIT and LTT. The results showed a strong correlation between LTT and MITT between immunodeficient patients and healthy controls. The sensitivity test for MTT was 90%, and the sensitivity test for LTT was 98%. MTI method can be considered as a non-radiactive evaluation of cell proliferation. Detecting cell proliferation with accurate, sensitive, fast, easy and safe method is more preferable than LIT.