Thermoelectric properties of tetrathiotetracene iodide crystals: modeling and experiment

A more complete physical model for nanostructured crystals of tetrathiotetracene-iodide that takes into account the interaction of carriers with the neighboring one-dimensional (1D) conductive chains and also the scattering on impurities and defects is presented. For simplicity, the 2D approximation is applied. It is shown that this model describes very well the temperature dependencies of electrical conductivity in the temperature interval between 180 and 300 K, and of the Seebeck coefficient between 50 and 300 K, the highest temperature for which the measurements were reported. For lower temperatures, it is necessary to also consider the fluctuations of dielectric phase that appear before the metal–dielectric transition. It is found that the predictions made in the 1D approximation are valid only if the crystal purity is not very high, and the electrical conductivity is limited up to ∼3.5×106Ω−1m−1 and the thermoelectric figure of merit up to ZT∼4

Reverse Shoulder Arthroplasty with <i>Latissimus Dorsi</i> Transfer for Humerus Fractures Sequelae

Relevance. Fractures of the proximal humerus occupy the 3rd place in the structure of fractures in the elderly. Failure to treat these injuries leads to irreversible changes in the shoulder. The main treatment for the latter is arthroplasty. The surgical treatment of this category of patients is still a difficult task. The purpose of this study was to compare the effectiveness of standard reverse arthroplasty with reverse arthroplasty in combination with the reconstruction of the external rotators of the shoulder or transposition of the latissimus dorsi. Materials and Methods. The retrospective evaluation of treatment results of 96 patients with consequences of shoulder injuries was conducted. Of these, 51 patients underwent standard reverse arthroplasty (group I), and 45 patients (group II) underwent arthroplasty with reconstruction of the external rotators of the shoulder or transposition of the latissimus dorsi. The female patients accounted for 68.8%. The duration of the injury varied from 8 months to 2.5 years, the follow-up — from 1 to 7 years (Me = 3.5). The results were assessed with VAS, ASES, UCLA scales. Results. The positive outcomes were observed in most patients. Complications: dislocations of the endoprosthesis occurred in 16.7%, infectious complications — in 5.2%, shoulder component instability — in 2.1%, fracture of the humeral diaphysis — in 3.1%, neurovascular bundle injury — in 2.1% of cases. In the patients of group I, dislocations occurred significantly more often than in the patients of group II. To reduce the risk of complications, a rational tactic has been developed for treating patients with consequences of shoulder injuries. If electroneuromyography values from the deltoid muscle were less than 40% of the contralateral side, or if mineral bone density T-score was less than 2.5 SD, arthroplasty was not performed. During arthroplasty, it is necessary to perform the direct suturing of the of the infraspinatus and teres minor tendons to the humerus. If it is impossible, the latissimus dorsi transfer is indicated. Conclusion. Reverse arthroplasty in the treatment of the humerus fractures sequelae is an effective technique. To reduce the risk of complications, it is necessary to provide the additional stability of the endoprosthesis by reconstruction of the external rotators or latissimus dorsi transfer. It is advisable to refrain from arthroplasty in cases of severe deltoid hypotrophy and severe osteoporosis