HERA: A Timepix-based radiation detection system for Exploration-class space missions.

The Hybrid Electronic Radiation Assessor (HERA) system is a Timepix-based ionizing radiation detector built for NASA Exploration-class crewed missions. The HERA performs data analysis on-system and generates telemetry messages for ingestion, display, and relay by the spacecraft. Several iterations of the hardware have been flown aboard the International Space Station as payloads to test system operation and gain experience with the hardware in the space radiation environment. The HERA system and its payload operations are described, and data collected by the various HERA systems are presented.

The importance of time-resolved personal Dosimetry in space: The ISS Crew Active Dosimeter.

Monitoring space radiation is of vital importance for risk reduction strategies in human space exploration. Radiation protection programs on Earth and in space rely on personal and area radiation monitoring instruments. Crew worn radiation detectors are crucial for successful crew radiation protection programs since they measure what each crewmember experiences in different shielding configurations within the space habitable volume. The Space Radiation Analysis Group at NASA Johnson Space Center investigated several compact, low power, real-time instruments for personal dosimetry. Following these feasibility studies, the Crew Active Dosimeter (CAD) has been chosen as a replacement for the legacy crew passive radiation detectors. The CAD device, based on direct ion storage technology, was developed by Mirion Dosimetry Services to meet the specified NASA design requirements for the International Space Station (ISS) and Artemis programs. After a successful Technology demonstration on ISS, the CAD has been implemented for ISS Crew operations since 2020. The current paper provides an overview of the CAD development, ISS results and comparison with the ISS Radiation Assessment Detector (RAD) and the Radiation Environment Monitor 2 (REM2) instruments.

Clinical diagnostic exome sequencing in dystonia: Genetic testing challenges for complex conditions.

Patients with dystonia are particularly appropriate for diagnostic exome sequencing (DES), due to the complex, diverse features and genetic heterogeneity. Personal and family history data were collected from test requisition forms and medical records from 189 patients with reported dystonia and available family members received for clinical DES. Of them, 20.2% patients had a positive genetic finding associated with dystonia. Detection rates for cases with isolated and combined dystonia were 22.4% and 25.0%, respectively. 71.4% of the cohort had co-occurring non-movement-related findings and a detection rate of 24.4%. Patients with childhood-onset dystonia trended toward higher detection rates (31.8%) compared to infancy (23.6%), adolescence (12.5%), and early-adulthood onset (16%). Uncharacterized gene findings were found in 6.7% (8/119) of cases that underwent analysis for genes without an established disease relationship. Patients with intellectual disability/developmental delay, seizures/epilepsy and/or multifocal dystonia were more likely to have positive findings (P = .0093, .0397, .0006). Four (2.1%) patients had findings in two genes, and seven (3.7%) had reclassification after the original report due to new literature, new clinical information or reanalysis request. Pediatric patients were more likely to have positive findings (P = .0180). Our observations show utility of family-based DES in patients with dystonia and illustrate the complexity of testing.

Biomechanical analysis of anterior poly-methyl-methacrylate reconstruction following total spondylectomy for metastatic disease.

STUDY DESIGN: Three reconstruction options were evaluated biomechanically following total spondylectomy using human cadaveric spine specimens. OBJECTIVES.: To evaluate and compare the stability of combined anterior and posterior fixation incorporating poly-methyl-methacrylate with alternative accepted reconstruction techniques. SUMMARY OF BACKGROUND DATA: Total spondylectomy represents the most radical option for decompression in metastatic spinal cord compression. Poly-methyl-methacrylate is considered a useful adjunct in spinal column stabilization and arthrodesis; however, there is little published biomechanical data to support its use in this setting. METHODS: Ten fresh-frozen human cadaveric spines (T9-L3) were used. After intact analysis, a total spondylectomy was performed at T12. Three potential reconstruction techniques were tested for their ability to restore stiffness to the specimen: 1) multilevel posterior pedicle screw instrumentation from T10-L2; 2) anterior instrumentation (ATL Z plate II) and rib graft at T11-L1 with multilevel posterior pedicle screw instrumentation from T10-L2; and 3) anterior cement (Simplex P) and pins construct (T12) with multilevel posterior pedicle screw instrumentation from T10-L2. Each of the three potential reconstruction techniques was tested on each specimen in random order using nondestructive testing under load control. RESULTS: Only combined stabilization techniques (e.g., anterior instrumentation and rib graft with multilevel posterior pedicle screw instrumentation and anterior cement-and-pins construct with multilevel posterior pedicle screw instrumentation) restored stiffness to a level equivalent to or higher than that of the intact spine in all loading modes (P < 0.05). Anterior cement-and-pins construct with multilevel posterior pedicle screw instrumentation provided more stability to the specimen than anterior instrumentation and rib graft with multilevel posterior pedicle screw instrumentation in compression and flexion testing (P < 0.05). Posterior instrumentation alone did not restore stiffness to the intact level in compression and flexion testing (P < 0.005). CONCLUSIONS: Combined anterior and posterior reconstruction using a cement construct provides equal to or more stability than the intact spine in all testing modes. Posterior stabilization alone is an inferior method of reconstruction following total spondylectomy. Poly-methyl-methacrylate has the advantage over traditional anterior reconstruction techniques in that it can be inserted using a posterior approach.