Development of a two-channel system for monitoring the mirror elements of the Millimetron space observatory.

The paper presents the results of the development of an onboard two-stage telescope monitoring (control) system of the Millimetron space observatory. A 3D laser scanner is used for the preliminary inspection of the reflector elements, and an image analyzer based on the Foucault knife method is used for the final one. The results of the calculation and modeling of the monitoring system for tuning the telescope elements into space are presented. The signals formed in the system are calculated, including using data on the actual shape of the manufactured mirror elements. Estimates of the expected measurement accuracy are given, and the test results of the developed system are presented.

Degree of improving TMS focality through a geometrically stable solution of an inverse TMS problem.

The Transcranial Magnetic Stimulation (TMS) inverse problem (TMS-IP) investigated in this study aims to focus the TMS induced electric field close to a specified target point defined on the gray matter interface in the M1HAND area while otherwise minimizing it. The goal of the study is to numerically evaluate the degree of improvement of the TMS-IP solutions relative to the well-known sulcus-aligned mapping (a projection approach with the 90∘ local sulcal angle). In total, 1536 individual TMS-IP solutions have been analyzed for multiple target points and multiple subjects using the boundary element fast multipole method (BEM-FMM) as the forward solver. Our results show that the optimal TMS inverse-problem solutions improve the focality - reduce the size of the field "hot spot" and its deviation from the target - by approximately 21-33% on average for all considered subjects, all observation points, two distinct coil types, two segmentation types, two intracortical observation surfaces under study, and three tested values of the field threshold. The inverse-problem solutions with the maximized focality simultaneously improve the TMS mapping resolution (differentiation between neighbor targets separated by approximately 10 mm) although this improvement is quite modest. Coil position/orientation and conductivity uncertainties have been included into consideration as the corresponding de-focalization factors. The present results will change when the levels of uncertainties change. Our results also indicate that the accuracy of the head segmentation critically influences the expected TMS-IP performance.

[Anterior stabilization of the CI-CIII vertebrae after transoral removal of an aggressive aneurysmal bone cyst of the CII vertebra (a case report and literature review)]. / Peredniaia stabilizatsiia SI-SIII pozvonkov posle transoral'nogo udaleniia agressivnoi anevrizmaticheskoi kisty SII pozvonka (klinicheskoe nabliudenie i obzor literatury).

Treatment of patients with atlantoaxial instability caused by various diseases of the skull base and craniovertebral junction combined with ventral compression of the brainstem is a complex issue that is ambiguously resolved in different ways. We present a case of stepped treatment, the most important component of which was successful transoral removal of an aggressive aneurysmal bone cyst of the CII vertebra with anterior CI-CIII segment stabilization using an individual system, which was performed through the same approach. CLINICAL CASE: A 31-year-old male patient presented with destruction of the CII body and odontoid process affected by an aggressive aneurysmal bone cyst causing disintegration of the CII posterior wall and odontoid process, which clinically manifested by constricted motion and pain in the cervical spine. RESULTS: Three-step surgical treatment was performed. First, we performed a puncture biopsy of the CII body through the submandibular approach as well as posterior occipitospondylodesis with metal instrumentation from the occipital bone level to the CIV vertebra. Two months later, the patient underwent transoral removal of the CII body and odontoid process lesion and anterior CI-CIII segment stabilization using an individual cover metal system through the same approach. Two weeks after the second intervention, the occipitospondylodesis was transformed to a posterior CI-CIII stabilization system. Control CT 8 months after surgery showed the correct position of both stabilization systems. CONCLUSION: The use of individual instrumentation for anterior stabilization of the CI-CIII vertebrae in various diseases of the craniovertebral junction area is an effective and promising technique.

Estimates of peak electric fields induced by Transcranial magnetic stimulation in pregnant women as patients using an FEM full-body model.

Transcranial magnetic stimulation (TMS) for treatment of depression during pregnancy is an appealing alternative to fetus-threatening drugs. However, no studies to date have been performed that evaluate the safety of TMS for a pregnant mother patient and her fetus. A full-body FEM model of a pregnant woman with about 100 tissue parts has been developed specifically for the present study. This model allows accurate computations of induced electric field in every tissue given different locations of a shape-eight coil, a biphasic pulse, common TMS pulse durations, and using different values of the TMS intensity measured in SMT (Standard Motor Threshold) units. Our simulation results estimate the maximum peak values of the electric field in the fetal area for every fetal tissue separately and for the TMS intensity of one SMT unit.