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Silica has the highest demonstrated potential of any phase to preserve microfossils on Earth and therefore may host potential biosignatures on Mars. We detected hydrated silica in Jezero crater, the landing site of the National Aeronautics and Space Administration's Mars 2020 rover mission, by applying Dynamic Aperture Factor Analysis/Target Transformation to images from the Compact Reconnaissance Imaging Spectrometer for Mars. Hydrated silica detections with Dynamic Aperture Factor Analysis/Target Transformation were verified using commonly accepted Compact Reconnaissance Imaging Spectrometer for Mars analysis methods. The morphology of geologic units associated with silica was characterized with high‐resolution imaging. Several hypotheses are presented for the formation environment of hydrated silica. All are testable via in situ investigation. We assess the likelihood of silica to preserve biosignatures in these different scenarios based on habitability considerations and biosignature preservation in Earth analog environments and materials. Also reported are possible detections of hydrated silica in the Nili Fossae basement and olivine‐rich units, as well as Al‐phyllosilicate within Jezero crater. Key Points: Hydrated silica is detected in Jezero crater and could have formed in a variety of environments with different degrees of habitabilityHydrated silica is associated with smooth dark‐toned material that covers the olivine‐rich unitHydrated silica in Jezero crater is an excellent target for in situ investigation for biosignatures [ABSTRACT FROM AUTHOR]

The independent neurovascular anatomy of the long head of the triceps brachii and its suitability as a free muscle transfer have been extensively studied. Instead muscle transposition of the long head of the triceps brachii to enhance elbow flexion has been rarely described. We describe in this paper two cases of injury of brachial plexus sequel in which transposition was performed only on the long head of the triceps. The elbow fl exion was improved, the extension was preserved. [ABSTRACT FROM AUTHOR]

Highlights: [•] Levels of BDNF diminished in the striatum and cortex after striatal lesion with quinolinic acid. [•] The transplantation of bone marrow stem cells into the striatum increases BDNF concentrations in striatum and cortex. [•] The transplanted bone marrow cells are the most probable source of BDNF. [ABSTRACT FROM AUTHOR]

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Hemophilia causes injuries of peripheral nerves secondary to compressions by hematoma. In general, these injuries recover spontaneously after the cause of the compression is solved. A case of a 16-year-old adolescent with injury of the left femoral nerve, causing loss of the extension of the knee is described herein. During the evolution there was no recovery. For this reason a tendinous transfer of the femoral biceps was practiced. This technique was described formerly for the correction of poliomyelitis. Excellent results were obtained with complete recovery of the extension and force 4+/5. [ABSTRACT FROM AUTHOR]

Introduction: An anatomical study of the sural nerve in 20 fresh cadavers was carried out, with the main aim of knowing the anatomy of the sural nerve and the relationships with the anatomical points to facilitate its identification in different clinical and surgical procedures. Materials and methods: From fresh cadavers with ages between 20 and 40 years and less than 48 hours of death, 20 legs were studied. Through a posterior incision the sural nerve was dissected from the popliteal region until the lateral malleolus, identifying the medial sural cutaneous nerve and the communicating branch of the common peroneal nerve. Measures were made in centimeters. Results: In 70% of the cases, the sural nerve was composed by the connection of the medial sural cutaneous nerve and the communicating branch of the common peroneal nerve and in 30% only by the medial sural cutaneous nerve. This branch was present in 100% of the cases. The communicating branch was present without connection with the medial sural cutaneous nerve in 15%, and in the other 15% this branch was absent. In 57% the nervous connection was proximal to the miotendinous union of the gastrocnemius. The width of the miotendinous union of the gastrocnemius were between 5 to 8 cm (average 6.5 cm). The sural nerve was found 2.6 cm on average medial to the lateral border of the union. In the 6 cases of connection distal to the miotendinous union, the sural medial nerve passed 2 cm in average medial to the lateral border of the union, and the sural lateral to 0.8 cm medial of the same reference mentioned. Regarding the insertion of the Achilles' tendon, the sural nerve passed 2.25 cm previous to the same and in relation to the most prominent and posterior part of the lateral malleolus it passed 2 cm in average. Discussion: This study showed that is possible to find the sural nerve with security if the anatomical points are identified well to preserve it in different surgeries or to harvest the flaps in neurological studies and harvesting it for grafting or nerve biopsy. [ABSTRACT FROM AUTHOR]

Induction of tetraploidy in commercial tanier was successfully achieved in vitro. Tissue cultures of a tanier [Xanthosoma sagittifolium (L.) Schott cv. 'Inglesa', 2n = 26] were established and maintained on modified nutrient media containing various concentrations of MURASHIGE and SKOOG basal salts, vitamins, sucrose, BA and IAA or 2,4-D. Cultures were exposed continuously for 8 days to 0, 12.5, 25 and 50 mg/l colchicine incorporated in the media. The colchicine-treated tissue cultures yielded diploids (2n = 26), tetraploids (2n = 52) and aneuploids (2n - 2 = 24) respectively. The diploids produced on average one leaf and 4 suckers more per plant than the tetraploids, while plant height increased at about the same rate. Continuous exposure of tanier tissue cultures to colchicine is an effective method for the production of synthetic tetraploids that may be hybridized with noncommercial root rot-resistant tetraploids. [ABSTRACT FROM AUTHOR]

The spatial correlation in a reverberation chamber as a function of either the wavelength or the displacement is discussed. It is shown that the results from simulations are consistent with theory when the wavelength is changed. However, when the receiver is moved in the reverberation chamber, the spatial correlation differs from theory. [ABSTRACT FROM AUTHOR]

A simple method for estimating the mode-stirring efficiency in a reverberation chamber is presented. It is shown that estimating the Rician K-factor is more relevant in looking for optimal Rayleigh stirring conditions than using goodness-of-fit tests. Good agreement is reported between simulations and experiments. [ABSTRACT FROM AUTHOR]

Highlights • Amygdala electrical stimulation promotes spatial memory recovery in fimbria-fornix lesioned rats. • Amygdala stimulation induces an increase in MAP-2 and GAP-43 levels in the hippocampus and prefrontal cortex from 24 to 96 h in healthy rats. • Post training amygdala stimulation increases MAP-2 and GAP-43 levels in the hippocampus and prefrontal cortex in fimbria-fornix lesioned rats. Abstract The relationships between affective and cognitive processes are an important issue of present neuroscience. The amygdala, the hippocampus and the prefrontal cortex appear as main players in these mechanisms. We have shown that post-training electrical stimulation of the basolateral amygdala (BLA) speeds the acquisition of a motor skill, and produces a recovery in behavioral performance related to spatial memory in fimbria-fornix (FF) lesioned animals. BLA electrical stimulation rises bdnf RNA expression, BDNF protein levels, and arc RNA expression in the hippocampus. In the present paper we have measured the levels of one presynaptic protein (GAP-43) and one postsynaptic protein (MAP-2) both involved in synaptogenesis to assess whether structural neuroplastic mechanisms are involved in the memory enhancing effects of BLA stimulation. A single train of BLA stimulation produced in healthy animals an increase in the levels of GAP-43 and MAP-2 that lasted days in the hippocampus and the prefrontal cortex. In FF-lesioned rats, daily post-training stimulation of the BLA ameliorates the memory deficit of the animals and induces an increase in the level of both proteins. These results support the hypothesis that the effects of amygdala stimulation on memory recovery are sustained by an enhanced formation of new synapses. [ABSTRACT FROM AUTHOR]

Amygdala seems to promote the consolidation of plastic modification in different brain areas and these long-term brain changes require a rapid de novo RNA and protein synthesis. We have previously shown that basolateral amygdala electrical stimulation produces a partial recovery of spatial memory in fimbria-fornix lesioned animals and it is also able to increase the BDNF protein content in the hippocampus. The emerging question is whether these increased BDNF protein content arises from previously synthesized RNA or from de novo RNA expression. Now we address the question if amygdala electrical stimulation 15 min after daily water maze training produces a rapid de novo RNA synthesis in the hippocampus, a critical brain area for spatial memory recovery in fimbria-fornix lesioned animals. In addition, we also study RNA arc expression, a gene which is essential for memory and neural plasticity processes. To this purpose, we study amygdala stimulation effects on the expression of plasticity related-early-genes bdnf and arc in the hippocampus of fimbria-fornix lesioned animals trained in a water-maze for 4 days. We also checked on the expression of both genes in non-lesioned, untrained animals (acute condition) at 0.5, 1, 2 and 24 h after basolateral amygdala electrical stimulation. Our data from trained animals confirm that daily amygdala electrical stimulation 15 min after water maze training produces a partial memory recovery and that is coupled to an increase of bdnf and arc genes expression in the hippocampus. Additionally, the acute study shows that a single session of amygdala stimulation induces a transient increase of both genes (peaking at 30 min). These results confirm the memory improving effect of amygdala stimulation in fimbria-fornix-lesioned animals and sustain the assumption that the memory improving effect is mediated by newly synthetized BDNF acting on a memory relevant structure like the hippocampus. The increased amount of BDNF within the hippocampus seems to be locally synthetized by mechanisms activated by the amygdala stimulation. [ABSTRACT FROM AUTHOR]

Highlights • L-buthionine sulfoximine diminishes distance travelled in open field test. • Discrimination of novel object is not impaired by BSO treatment. • Locomotion impairment is associated with arc overexpression in striatum. Abstract The aims of the present work were to evaluate the exploratory activity in Sprague-Dawley rats, as well as to analyze the nigral and striatal mRNA expression of the plasticity-related genes bdnf and arc after L-buthionine sulfoximine (BSO) injection into substantia nigra compacta. Lesioned rats traveled less distance in open field but did not show a decline in the novel object recognition test. On the other hand, RT-PCR analysis showed overexpression of striatal arc 24 h post-lesion; no significant changes in bdnf expression were observed in nigral or striatal tissue. These results suggest that intranigral BSO injection causes impairment in exploratory behavior in these rats, by affecting locomotion, which is associated with changes in striatal synaptic plasticity. [ABSTRACT FROM AUTHOR]