First principle calculations were performed using Density functional theory within the local spin density approximation (LSDA) to understand the electronic properties of Au (100)+TBT system and compare the results with Au (100) and bulk Au properties. Band structure, the total DOS and charge density for these materials are calculated. We found that the HOMO for Au (100)+TBT becomes broader than Au (100) and bulk Au and d orbitals have the most contribution in covalent band. The electron densities overlap between Au atoms implies a large covalent bonding. Our calculations indicate that conjugated systems such as (TBT) enhance electric conductance.

Surface sediment samples were collected from Tanzanian major commercial ports and studied for the distribution and behavior of tributyltin (TBT) compounds and heavy metals. The content of TBT in sediments ranged from ND­3670 ng (Sn) g1 dry wt (1780 ± 1720) (Mean ± SD) at Zanzibar and from ND­16700 ng (Sn) g1 dry wt (4080 ± 7540) at Dar es Salaam ports, respectively. Maximum TBT levels were detected inside the both ports. Metabolic degradation of butyltin compounds (BTCs) showed that MBT + DBT > TBT %, this may be attributed by the warm ambient water and intense sunlight in the tropical regions. A sequential extraction procedure was undertaken to provide detailed chemical characteristics of heavy metals in the sediments. The procedure revealed that about 50 % of Fe in the both ports is in immobile fraction (residual fraction) while other metals; Cd, Cu, Ni, Co, Zn, Pb, and Mn were mostly found in exchangeable or carbonate fractions and thus can be easily remobilized and enter the aquatic food chain. This paper provides basic information of TBT compounds contamination and chemical characteristics of heavy metals in the marine ecosystem in Tanzania. To our knowledge, this is the first documentation of Organotin compounds (OTCs) in marine environments in East Africa and suggests the importance of further detailed OTCs studies in other sub­ Saharan Africa regions.

Background: Kidney transplant recipients need self-management during their lifetime, and training these patients is essential for the realization of self-management. Teach-back training (TBT) was used to receive, understand, and retain information. This study aimed to determine the effect of TBT on self-management in kidney transplant recipients. Methods: In this clinical trial study, 84 kidney transplant recipients who referred to the clinic of Imam Khomeini Hospital in Urmia (a city in northwest of Iran), from January to March 2017, were selected through convenience sampling and randomly assigned to intervention and control groups. In the intervention group, educational content was presented for each patient with TBT in 5 sessions of 60 minutes. Data were collected before and after the intervention by a special Self-Management Questionnaire for Kidney Transplant Recipients in five areas as follows: self-monitoring, self-care behavior in daily living, early detecting and coping with abnormalities after kidney transplantation, stress management and the category of non-categorized area. This is a valid and reliable questionnaire (α =0. 76). Collected data were analyzed by independent t-test and Mann-Whitney test. Statistical analysis was performed using SPSS 20 and P≤ 0. 05 was considered as significant. Results: Independent t-test showed that the mean of self-management score between the control and intervention groups was not statistically significant before the intervention (P=0. 90). The mean score of self-management increased after implementation of TBT in the intervention group compared to the control group, and the difference was statistically significant (P=0. 001). Conclusion: The implementation of TBT method is effective in promoting self-management of kidney transplant recipients. Therefore, it is recommended that this method should be used to train the patients to better understand the components of self-management.

The goal of this paper is to use Sensitivity Analysis (SA) method to improve the performance of the system and to make the best decision of choosing the appropriate dimensions of the flexible link to optimize the system. In this paper the SA of the geometric parameters such as: length, thickness and width of a single link flexible manipulator on maximum deflection (MD) of the end effector and vibration energy (VE) of that point by using Sobol’s method are conducted. The full dynamic model of the system is developed based on Gibbs-Appel (G-A) formulation. In this paper, Timoshenko beam theory (TBT) and Euler-Bernoulli beam theory (EBBT) are used to find the end-point MD and VE of the end effector. So, at first the assumption of TBT has been performed to consider the effects of shear and rotational inertia. Then, EBBT is used. In continue Sobol’s sensitivity analysis method is applied to determine how VE and end-point MD is influenced by those geometric parameters. Finally, results of two mentioned theories are compared.