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Background: Stroke is a rare neurological disease in children, with an annual incidence of 2 - 13/100,000 children per year. Pediatric stroke is associated with significant morbidity and mortality lasting many decades. Diagnosis of pediatric stroke is challenging and often delayed, limiting options for acute intervention, and the pharmacological and mechanical recanalization strategies that have revolutionized adult stroke remain undefined in children. Clinicians are left to draw conclusions from other retrospective cohort studies or case reports and extrapolate adult guidelines to the pediatric population. The TIPS trial eligibility criteria are often used in clinical practice, despite not being validated for this purpose. We present here the case of a healthy 14 year old male who was treated with intravenous tissue plasminogen activator (IV tPA) for a presumed arterial ischemic stroke without large vessel occlusion on neuroimaging. Methods: Retrospective chart review Results: Not applicable Conclusions: Following the administration of IV tPA, the patient made a full recovery. While we do not recommend the routine use of IV tPA for treatment of presumed large vessel or small vessel in children, we suggest that the decision to proceed with IV tPA be considered on a case-by-case basis.
Two metal fillers with TiC nanoparticles (TiC NPs) of less than 100 nm for the overlay process is an alternative to hardfacing for treating surfaces subjected to severe wear. In this work, the effect of tribological behavior for TiC NPs addition on two Co-based filler materials, as well as the dilutions, was studied. Mixtures of Co-based filler metals without and with 0.5% and 2% TiC NPs were deposited onto D2 steel plates using PTA (Plasma Transferred Arc). The BET surface area was 0.17 m2 g-1 and 0.31 m2 g-1, respectively, for Stellite 6 and 12. The distribution of ca 23% macroporous for Stellite 6 was sufficient to get inside the TiC NPs, as well as in the case of Stellite 12, with a pore distribution of ca 13%. Stellite 12 has an increase in the dilutions (70%) and enthalpies showed endothermic reactions. Stellite 6 with NPs was determined to be most effective in increasing the wear resistance.
Laser welding processes offer significant advantages such as high welding speed, narrow heat affected zone and quality of the welding joint. In this study, the process parameters of laser power and welding speed were modified for AISI 1018 steel plates of 8 mm thickness and compared using finite element method. The results of cross-section microstructure, heat affected zone and fusion zone were characterized. The grain refinement was affected as the parameters were modified. Tensile and microhardness tests were performed to determine the mechanical properties of the welding joints. Microhardness increased in fusion zone and decreased in heat affected zone. Tensile test showed ductile fracture in heat affected zone of the welding joints. The simulated profiles were compared with the experimental observations showing a reasonable agreement.
The effect of life stress on suicidal symptoms during adolescence is well documented. Stressful life events can trigger suicidality, but most adolescents are resilient and it is unclear which factors protect against the deleterious impact of stress. Social support is thought to be one such factor. Therefore, we investigated the buffering effect of specific sources of social support (parental and peer) on life stress (interpersonal and non-interpersonal) in predicting suicidal symptoms during adolescence. In order to test the specificity of this stress buffering, we also examined it with regard to dysphoric mood.
Data come from the Adolescent Development of Emotions and Personality Traits (ADEPT) Project, a cohort of 550 adolescent females aged 13.5–15.5 recruited from Long Island. Self-reported social support, suicidality, and dysphoria were assessed at baseline and suicidality and dysphoria were assessed again at 9-month follow-up. Life stress was assessed by interview at the follow-up.
High levels of parental support protected adolescent girls from developing suicidal symptoms following a stressor. This effect was less pronounced for peer support. Also, social support did not buffer the pathogenic effects of non-interpersonal stress. Finally, social support did not buffer the effect of life stress on dysphoric symptoms.
Altogether, our results highlight a distinct developmental pathway for the development of suicidal symptoms involving parental support that differs from the development of dysphoria, and signifies the importance and specificity of social support in protecting against suicidality in adolescent girls.
The sexual performance of Anastrepha ludens males of the Tapachula-7 genetic sexing strain, produced via selection based on mating success, was compared with that of males produced without selection in competition with wild males. Mating competition, development time, survival, mass-rearing quality parameters and pheromone production were compared. The results showed that selection based on mating competitiveness significantly improved the sexual performance of offspring. Development time, survival of larvae, pupae and adults, and weights of larvae and pupae increased with each selection cycle. Differences in the relative quantity of the pheromone compounds (Z)-3-nonenol and anastrephin were observed when comparing the parental males with the F4 and wild males. The implications of this colony management method on the sterile insect technique are discussed.
We obtained simultaneous images of solar plage on 7 May 1991 with Goddard Space Flight Center’s Solar EUV Rocket Telescope and Spectrograph (SERTS), the Very Large Array (VLA), and the NASA/NSO spectromagnetograph at Kitt Peak. Using intensity ratios of Fe XVI to Fe XV emission lines, we find that the coronal plasma temperature is 2.5 ± 0.3 ×lO6 K throughout the region. The column emission measure ranges from 2.6 × 1027 to 1.3 × 1028 cm−5. The calculated structure and intensity of the 20 cm wavelength thermal bremsstrahlung emission from the hot plasma observed by SERTS is quite similar to the observed structure and intensity of the 20 cm microwave emission observed by the VLA. Using the revised coronal iron abundance of Meyer (1991, 1992), we find no evidence for either cool absorbing plasma or for contributions from thermal gyroemission. Combining the observed microwave polarization and the SERTS plasma parameters, we calculate a map of the coronal longitudinal magnetic field. The resulting values, ~ 30 – 60 Gauss, are comparable to extrapolated values of the potential field at heights of 5,000 and 10,000 km.
For birds, we tested the efficacy of a technique used to obtain faecal samples and their seed content from bats by placing plastic sheets below mist nets. This method was compared with that of collecting faecal samples using cotton bags. Plastic sheets were placed below each of eight mist nets to obtain faecal samples from birds caught in cloud forest remnants. Each bird was then placed separately in a cotton bag to catch any other seeds excreted. There were 84 faecal samples in total: 64 with no seeds and 20 with seeds; of the latter 65% were obtained from the plastic sheets. A total of 407 seeds were collected, 317 from 11 plant species were collected on the plastic sheets and 90 belonging to six plant species in the bags. Seed richness and abundance were significantly greater for samples obtained using the plastic sheets than with the cotton bags. Although the number of bird faecal samples obtained did not differ between methods (13 vs 7), with the plastic sheets the number of faecal samples with seeds increased. Thus, to obtain more representative faecal samples from frugivorous birds, we strongly recommend the use of plastic sheets as part of the technique.
In this study, rearing systems for, and the quality and demographic parameters of, a wild strain (WS) and two laboratory strains (LSs; one maintained on a torula yeast-casein diet and the other on a starter-gel diet) were determined for the American guava fruit fly Anastrepha striata (Schiner). No differences were observed between the LSs, but there were significant differences between the LSs and WSs. The LSs had the highest values for larval recovery, pupal weight, egg hatch, number of eggs/female per day, net reproductive rate and intrinsic rate of increase. Therefore, during a short oviposition period, the LSs had a high fecundity. There were no differences in pupation at 24 h and larval weight between the WS and LS. However, the values of parameters, adult emergence, female and male life expectancies, age at first oviposition, oviposition and post-oviposition periods and mean generation time were the highest in the WS.
The organogenesis of the digestive system was described in the Amazonian pimelodid catfish species Pseudoplatystoma punctifer from hatching (3.5 mm total length, TL) to 41 days post-fertilization (dpf) (58.1 mm TL) reared at 28°C. Newly hatched larvae showed a simple digestive tract, which appeared as a straight undifferentiated and unfolded tube lined by a single layer of columnar epithelial cells (future enterocytes). During the endogenous feeding period, comprised between 20 and 96 h post-fertilization (3.5 to 6.1 mm TL), the larval digestive system experienced a fast transformation with the almost complete development and differentiation of most of digestive organs (buccopahrynx, oesophagus, intestine, liver and exocrine pancreas). Yolk reserves were not completely depleted at the onset of exogenous feeding (4 dpf, 6.1 mm TL), and a period of mixed nutrition was observed up to 6 to 7 dpf (6.8 to 7.3 mm TL) when yolk was definitively exhausted. The stomach was the organ that latest achieved its complete differentiation, characterized by the development of abundant gastric glands in the fundic stomach between 10 and 15 dpf (10.9 to 15.8 mm TL) and the formation of the pyloric sphincter at the junction of the pyloric stomach and the anterior intestine at 15 dpf (15.8 mm TL). The above-mentioned morphological and histological features observed suggested the achievement of a digestive system characteristic of P. punctifer juveniles and adults. The ontogeny of the digestive system in P. punctifer followed the same general pattern as in most Siluriform species so far, although some species-specific differences in the timing of differentiation of several digestive structures were noted, which might be related to different reproductive guilds, egg and larval size or even different larval rearing practices. According to present findings on the histological development of the digestive system in P. punctifer, some recommendations regarding the rearing practices of this species are also provided in order to improve the actual larval rearing techniques of this fast-growing Neotropical catfish species.
Recently they have discovered a large number of oil wells, however these are found in deeper waters. So it is necessary to develop a repair's methodology and inspection for this type of system to prove its operation. This research was focused to establish a methodology for evaluating residual stress generated from the application of solder in a subsea environment, in order to establish whether there is a relationship between residual stress and the depth of the sea. For this purpose was used underwater electrodes (UW -CS- 1) and an API 5L X65 steel to the development of underwater welds, which was welded at 10 and 15 meters depth by a diver welder on site. The measurement of residual stress is developed using non-destructive techniques, the first one was ultrasound technique (UT) which was the technique proposed by viability to being applied in site and as a second option, was applied X-ray diffraction (XRD), with the objective to validate the results obtained by ultrasound technician. The results showed a similar behavior between both non-destructive techniques. In this study was observed the tendency to increase the level of residual stress with increasing the work depth.
Silicon nanoparticles of 100 nm obtained by high-energy ball milling were characterized by X-ray diffraction (XRD) and transmission electronic microscopy (TEM). Results show dark areas due to a staking of defects. On the other hand, brighter areas exhibit a combination of small crystalline and amorphous zones. To fulfill and cover the micro-cracking and micro-pores generated during the welding process of 304 stainless steels joined by brazing, these nanoparticles were deposited directly in the fracture. The amorphous silicon drove the Transient Liquid Phase (TLP) at 1000°C for 20 min. This amorphous silicon decreases the energies of reaction between the substrate and melting filler. TLP increases the wettability and capillary forces between micro-cracking and micro-pores; due to that, the eutectic phase contained by the melting filler forms a liquid. Moreover, the weld beads were characterized by Scanning Electron Microscopy (SEM) to analyze the effect of silicon nanoparticles on the weld beads. These results showed that the interaction of the Si nanoparticles with metallic filler in the melting zone decreases the size and change the morphology of the present phases as well as the zone of isothermic growth.
In order to increase the wettability and capillary forces of the filler metal between micro-cracking and micro-porous on the fracture surfaces of 304 stainless steels, methods of impregnation of Si and growth of Ni nanoparticles were used. These nanoparticles have a role inside the Transient Liquid Phase (TLP) and the substrate when using Brazing process. TLP can react with the nanoparticles previously deposited between micro-cracking and micro-porous and therefore promotes the nucleation and growth sites of phases and decreases the formation of eutectic structures. This method increases the effectiveness of metallic components reparation using Brazing process. Such effectiveness is indicated by an inspection of microstructural failure analysis, as a first stage, in the covered zone by the filler metal.
This study consisted of the characterization of longitudinal cracking pattern observed in weld joint in the manufacture of 304L steel pipelines with thin wall thickness by GTAW process. These tubes are used in food and automotive industries. The cracks grown in the liquid-solid interdendritic zones at high temperatures. It was found that the cracks are associated with change on solidification mode and presence of the holes produced by shrinkage. The change in the solidification mode was associated with the presence of second phase particles. The results suggest that the formation of cracks is promoted by increasing current during the welding although the heat input is constant.
The layered oxide LiVO2 recently has received more attention due to its interesting structural and magnetic behaviors involving the two-dimensional magnetic frustration in these systems. We synthesized a series of F-doped LiVO2 samples, and reported the F-doping effect on the structure and transition temperature Tt. The samples LiVO2-xFx (x=0, 0.1, 0.2 and 0.3) were characterized by X-ray diffraction, scanning electron microscope (SEM), differential scanning calorimetry (DSC), magnetic susceptibility and specific heat measurement. The structural analysis shows that with increasing x, the ratio of lattice parameter c/a increasing, i.e. in the a-b plane the lattice is compressed while in the c-axis direction the lattice expands. The DSC measurements show that a first-order phase transition happens at around 500 K, and the thermal hysteresis around phase transition temperature Tt increases with increasing x. Substitution of O with F ions results in a change of two dimensional characteristics and the distortion of the VO6 block in structure, which significantly influence the magnetic ordering transition temperature Tt.
The magnetism of CoRh nanoparticles (NPs) is investigated experimentally and theoretically. NPs of about 2 nm diameter have been synthesized by decomposition of organometallic precursors in mild conditions of pressure and temperature, under hydrogen atmosphere and in the presence of a polymer matrix. The magnetic properties are determined by SQUID and X-ray magnetic circular dichroism. All the studied CoRh clusters are magnetic with an average spin moment per atom that is significantly larger than the one of macroscopic crystals or alloys with similar concentrations. The experimental results and the comparison with theory suggest that the most likely chemical arrangement is a Rh core with a Co-rich outer shell and some degree of intermixing at the CoRh interface. A detailed analysis of the theoretical results from a local perspective shows that the spin and orbital moments of the Co and Rh atoms at the interface are largely responsible for the enhancement of the magnetization.
We have investigated the magnetic arrangment of 3d transition-metal stepped surface by using a self-consistent real-space tight-binding method. As expected, the presence of steps modifies locally the properties of a transition-metal surface. We emphasized the influence of atomic environment. We found for the (100)-Fe surface, an enhancement of the magnetic moments of the external edge of this step as compared to the flat surface. The results are not very sensitives to the step length. More striking is the case of the (100)-V stepped surface where atoms at the external edge display a large magnetic moment.