Ejecta from the DART-produced active asteroid Dimorphos.

Some active asteroids have been proposed to be formed as a result of impact events1. Because active asteroids are generally discovered by chance only after their tails have fully formed, the process of how impact ejecta evolve into a tail has, to our knowledge, not been directly observed. The Double Asteroid Redirection Test (DART) mission of NASA2, in addition to having successfully changed the orbital period of Dimorphos3, demonstrated the activation process of an asteroid resulting from an impact under precisely known conditions. Here we report the observations of the DART impact ejecta with the Hubble Space Telescope from impact time T + 15 min to T + 18.5 days at spatial resolutions of around 2.1 km per pixel. Our observations reveal the complex evolution of the ejecta, which are first dominated by the gravitational interaction between the Didymos binary system and the ejected dust and subsequently by solar radiation pressure. The lowest-speed ejecta dispersed through a sustained tail that had a consistent morphology with previously observed asteroid tails thought to be produced by an impact4,5. The evolution of the ejecta after the controlled impact experiment of DART thus provides a framework for understanding the fundamental mechanisms that act on asteroids disrupted by a natural impact1,6.

Successful kinetic impact into an asteroid for planetary defence.

Although no known asteroid poses a threat to Earth for at least the next century, the catalogue of near-Earth asteroids is incomplete for objects whose impacts would produce regional devastation1,2. Several approaches have been proposed to potentially prevent an asteroid impact with Earth by deflecting or disrupting an asteroid1-3. A test of kinetic impact technology was identified as the highest-priority space mission related to asteroid mitigation1. NASA's Double Asteroid Redirection Test (DART) mission is a full-scale test of kinetic impact technology. The mission's target asteroid was Dimorphos, the secondary member of the S-type binary near-Earth asteroid (65803) Didymos. This binary asteroid system was chosen to enable ground-based telescopes to quantify the asteroid deflection caused by the impact of the DART spacecraft4. Although past missions have utilized impactors to investigate the properties of small bodies5,6, those earlier missions were not intended to deflect their targets and did not achieve measurable deflections. Here we report the DART spacecraft's autonomous kinetic impact into Dimorphos and reconstruct the impact event, including the timeline leading to impact, the location and nature of the DART impact site, and the size and shape of Dimorphos. The successful impact of the DART spacecraft with Dimorphos and the resulting change in the orbit of Dimorphos7 demonstrates that kinetic impactor technology is a viable technique to potentially defend Earth if necessary.

Scaffolds as Structural Tools for Bone-Targeted Drug Delivery.

Although bone has a high potential to regenerate itself after damage and injury, the efficacious repair of large bone defects resulting from resection, trauma or non-union fractures still requires the implantation of bone grafts. Materials science, in conjunction with biotechnology, can satisfy these needs by developing artificial bones, synthetic substitutes and organ implants. In particular, recent advances in materials science have provided several innovations, underlying the increasing importance of biomaterials in this field. To address the increasing need for improved bone substitutes, tissue engineering seeks to create synthetic, three-dimensional scaffolds made from organic or inorganic materials, incorporating drugs and growth factors, to induce new bone tissue formation. This review emphasizes recent progress in materials science that allows reliable scaffolds to be synthesized for targeted drug delivery in bone regeneration, also with respect to past directions no longer considered promising. A general overview concerning modeling approaches suitable for the discussed systems is also provided.

[Microvascular decompression in hemifacial spasm: 13 cases report and review of the literature]. / Descompresión microvascular en espasmo hemifacial: Reporte de 13 casos y revisión de la literatura.

OBJECTIVE: The aim of this study is to describe the results of 13 patients with facial hemispasm, treated with microvascular decompression. METHODS: Between June 2005 and May 2014, 13 patients with facial hemispasm were operated, underwent microvascular decompression. The age, sex, duration of symptoms before surgery, and surgical finds, were all evaluated. In addition, postoperative results were also analyzed. RESULTS: Seven patients were women and 6 were men. The average age of the patients was 53 years. The average time between onset of symptoms and surgery ranged from 3 to 9 years. In all cases the facial hemispasm was typical, one with concomitant trigeminal neuralgia, observed in all neurovascular compression intraoperative. In decreasing order of frequency, the cause of compression was anterior inferior cerebellar artery, posterior inferior cerebellar artery, dolicomega basilar artery and dolicomega vertebral artery. The average time of postoperative follow-up after the surgery was 24 months. Complete relief from spasm occurred in 62%; 30% disappearance after 3 weeks-2 months (8% partial) and in 8% had no improvement. Regarding postoperative complications: 3 patients had facial paresis II-III in House-Brackman scale and 1 patient presented CSF leak. None of the patients in the serie had hearing loss or deafness. CONCLUSION: The microvascular decompression for facial hemispasm is a safe an effective procedure, which allows complete resolution of the disease in most cases.

Descompresión microvascular en espasmo hemifacial: reporte de 13 casos y revisión de la literatura / Microvascular decompression in hemifacial spasm: report of 13 cases and review of the literature

Objetivo: el propósito del presente trabajo es presentar los resultados de 13 pacientes con diagnóstico de espasmo hemifacial (EHF), en los cuales se realizó una descompresión microvascular (DMV). Material y Método: Desde Junio de 2005 a Mayo de 2014, 13 pacientes con diagnóstico de EHF fueron intervenidos quirúrgicamente, realizando una DMV. Se evaluó: edad, sexo, tiempo de evolución de la sintomatología, hallazgos intraoperatorios y resultados postoperatorios. Resultados: De los 13 pacientes intervenidos, 7 fueron mujeres y 6 varones. La media de edad fue de 53 años. El tiempo medio entre el inicio de la sintomatología y la intervención quirúrgica osciló entre 3 y 9 años. En todos los casos el EHF era típico, uno de ellos con neuralgia trigeminal concomitante, observándose en todos compresión neurovascular intraoperatoria. Por orden decreciente de frecuencia la causa de la compresión fue arteria cerebelosa anteroinferior, arteria cerebelosa posteroinferior, arteria dolicomega basilar y arteria dolicomega vertebral. El seguimiento postoperatorio fue en promedio de 24 meses. El 62% presentó desaparición postquirúrgica inmediata de la sintomatología preoperatoria, el 30% desaparición tras un período de 3 semanas a 2 meses (8% con mejoría parcial), y en el 8% no hubo mejoría. En cuanto a las complicaciones postoperatorias: 3 pacientes presentaron paresia facial II-III en la escala de House-Brackman (se recuperaron en un período de 6 meses), y 1 paciente presentó fístula de líquido cefalorraquídeo. Ninguno de los pacientes de la serie presentaron hipoacusia transitorio o permanente. Conclusión: La DMV como tratamiento del EHF es un procedimiento efectivo y seguro, que permite la resolución completa de la patología en la mayoría de los casos.

Objective: the aim of this study is to describe the results of 13 patients with facial hemispasm, treated with microvascular decompression.Method: Between June 2005 and May 2014, 13 patients with facial hemispasm were operated, underwent microvascular decompression. The age, sex, duration of symptoms before surgery, and surgical finds, were all evaluated. In addition, postoperative results were also analyzed. Results: 7 patients were women and 6 were men. The average age of the patients was 53 years. The average time between onset of symptoms and surgery ranged from 3 to 9 years. In all cases the facial hemispasm was typical, one with concomitant trigeminal neuralgia, observed in all neurovascular compression intraoperative. In decreasing order of frequency, the cause of compression was anterior inferior cerebellar artery, posterior inferior cerebellar artery, dolicomega basilar artery and dolicomega vertebral artery. The average time of postoperative follow-up after the surgery was 24 months. Complete relief from spasm occurred in 62%; 30% disappearance after 3 weeks-2 months (8% partial) and in 8% had no improvement. Regarding postoperative complications: 3 patients had facial paresis II-III in House-Brackman scale and 1 patient presented CSF leak. None of the patients in the serie had hearing loss or deafness. Conclusion: The microvascular decompression for facial hemispasm is a safe an effective procedure, which allows complete resolution of the disease in most cases.