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Wire and arc additively manufactured aluminum alloys are prone to porosity, leading to poor mechanical properties in samples, which hinders their broad industrial application. Laser and arc hybrid processes have garnered increasing attention for their potential to reduce porosity, stabilize the arc, and enhance deposition efficiency. This paper investigates the porosity, element distribution, microstructure evolution, and mechanical properties of 2319 aluminum alloy produced through the laser and cold metal transfer (laser-CMT) hybrid additive manufacturing process. In comparison with the as-deposited samples, the laser-CMT hybrid process decreases porosity, enhances element distribution, mitigates Cu element segregation, and results in increased θ′′ phase precipitation. Following T6 heat treatment, the ultimate tensile strength (UTS), yield strength (YS), and elongation of the x-direction specimens from the laser-CMT hybrid process are 450.0 MPa, 318.1 MPa, and 10.0%, respectively. These values are 11.27%, 7.03%, and 36.65% higher than those of the as-deposited samples. To validate the findings, a large-scale load-carrying frame for a commercial aircraft was fabricated, demonstrating the efficacy of the process. The paper also presents a detailed analysis of the strengthening mechanism. Samples deposited using the laser-CMT method exhibit reduced porosity and excellent mechanical properties, making this process promising for a wide range of applications.

Abstract Objective We analyzed the outcomes of patients suffering acute ischemic stroke (AIS) with large vessel occlusion (LVO) soon after pulmonary lobectomy. Methods We retrospectively reviewed the clinical records of patients who underwent pulmonary lobectomy to treat primary lung cancer. We retrieved clinical characteristics and the incidence of AIS with LVO. The clinical courses of patients who experienced AIS were reviewed. Results In 10 (0.3%) of 3406 patients, AIS with LVO developed soon (within 3 days) after pulmonary lobectomy. The lung resection site was on the left in eight patients (80%). All patients underwent thrombectomy and achieved complete recanalization (Thrombolysis in Cerebral Infarction [TICI] 3). The average time between symptom onset and recanalization was 165.5 min. Nine (90%) patients exhibited favorable outcomes (modified Rankin scale [mRS] score ≤ 2) at the 3-month follow-up. Conclusion Endovascular therapy effectively treats AIS with LVO that develops after lung surgery, and direct aspiration is a promising strategy. A large, multicenter study is warranted to further confirm these findings.

Nickel-iron alloy is broadly utilized in the industrial field due to its fabulous mechanical properties. How to prepare nickel-iron alloy with better corrosion resistance more efficiently is an important concern. Based on this, the WC particles enhanced nickel-iron coatings were fabricated by jet electrodeposition (JED) at a high current density of 100A/dm2. It was found that increasing the deposition temperature appropriately during JED is beneficial to obtain Ni-Fe-WC coating with the higher number of hard particles. Specifically, the maximum WC particles proportion reaches 4.47 wt% at 55 °C. The electrochemical corrosion behavior of coating was measured by polarization curve and electrochemical impedance spectroscopy (EIS). The polarization curve test results displayed that the Ecorr positively shifted from −0.402 to −0.281 V and the icorr reduced from 25.13 to 7.05 μA/cm2 with the increase of WC particles proportion. Meanwhile, the EIS test results exhibited that the impedance of coating enhanced from 12,720 to 59,140 Ω cm2. The neutral salt spray test (NSS) was used to simulate the corrosion of coating in a seawater environment. The NSS results showed that with the increase of WC particles, the corrosion products decreased gradually and the degree of corrosion decreased. The analysis showed that WC particles can help the grain growth and release the internal stress in the coating. Larger grain sizes reduces intergranular corrosion and smaller internal stress help to alleviate stress corrosion cracking. The above research can provide theoretical support for the efficient preparation of particle enhanced composite coating with strong corrosion resistance.

Vertebral artery stump syndrome (VASS) is a rare disease associated with a posterior circulation stroke after vertebral artery origin occlusion. We have herein presented a case of VASS that was effectively treated with endovascular intervention using retrograde recanalisation and the mechanism of VASS in our patient was thought to be a thrombus formed by stagnating flow.

Abstract Nanoparticle-reinforced metal matrix composite coatings have significant potential in mechanical part surface strengthening owing their excellent mechanical properties. This paper reports a phenomenon in which the grain orientation gradually evolves to (220) as the deposition current density increases when preparing nanoparticle-reinforced nickel-based composite coatings through jet electrodeposition (JED). During the preparation of the Ni-SiC composite coatings, the deposition current density increased from 180 A/dm2 to 220 A/dm2, and TC(220) gradually increase from 41.4% to 97.7%. With an increase of TC(220), the self-corrosion potential increases from −0.575 to −0.477 V, the corrosion current density decreases from 9.52 μA/cm2 to 2.76 μA/cm2, the diameter of the corrosion pits that after 10 days of immersion in a 3.5 wt% NaCl solution decreases from 278–944 nm to 153–260 nm, and the adhesion of the coating increases from 24.9 N to 61.6 N. Compared a conventional electrodeposition (CED), the Ni-SiC composite coating using JED has the advantages of a smooth surface morphology, high corrosion resistance, and strong adhesion, which are more obvious with an increase in TC(220).

ObjectiveBrain atrophy is an important imaging characteristic of cerebral small vascular disease (CSVD). Our study explores the linear measurement application on CT images of CSVD patients and develops a fully automatic brain atrophy classification model. The second aim was to compare it with the end-to-end Convolutional Neural Networks (CNNs) model.MethodsA total of 385 subjects such as 107 no-atrophy brain, 185 mild atrophy, and 93 severe atrophy were collected and randomly separated into training set (n = 308) and test set (n = 77). Key slices for linear measurement were manually identified and used to annotate nine linear measurements and a binary classification of cerebral sulci widening. A linear-measurement-based pipeline (2D model) was constructed for two-types (existence/non-existence brain atrophy) or three-types classification (no/mild atrophy/severe atrophy). For comparison, an end-to-end CNN model (3D-deep learning model) for brain atrophy classification was also developed. Furthermore, age and gender were integrated to the 2D and 3D models. The sensitivity, specificity, accuracy, average F1 score, receiver operating characteristics (ROC) curves for two-type classification and weighed kappa for three-type classification of the two models were compared.ResultsAutomated measurement of linear measurements and cerebral sulci widening achieved moderate to almost perfect agreement with manual annotation. In two-type atrophy classification, area under the curves (AUCs) of the 2D model and 3D model were 0.953 and 0.941 with no significant difference (p = 0.250). The Weighted kappa of the 2D model and 3D model were 0.727 and 0.607 according to standard classification they displayed, mild atrophy and severe atrophy, respectively. Applying patient age and gender information improved classification performances of both 2D and 3D models in two-type and three-type classification of brain atrophy.ConclusionWe provide a model composed of different modules that can classify CSVD-related brain atrophy on CT images automatically, using linear measurement. It has similar performance and better interpretability than the end-to-end CNNs model and may prove advantageous in the clinical setting.

Grassland ecosystems are a significant part of the global ecosystem and support the livelihoods of millions of people. The Inner Mongolia grassland is the largest temperate grassland in the world, and an important ecological barrier for China, but due to human activities and climate change it has been faced with an ecological crisis in recent years. In this study, a modified Carnegie-Ames-Stanford approach (CASA) model based on the Google Earth Engine platform was used to determine the net primary production (NPP) in the Inner Mongolia grassland from 2000 to 2020. The results show that the average annual NPP of the Inner Mongolia grassland is 278.63 g C/m2, and 83.22% of the total area has shown an increasing trend during the study period. We also analyzed the impact of land-use/cover change (LUCC) and climatic factors on NPP. We found that: (1) the total area of grassland increased from 2000 to 2010 and then decreased from 2010 to 2020. During the whole study period, although the grassland area increased slightly by 4728.69 km2 because of LUCC, the overall effect of LUCC on grassland NPP was negative, with a loss of 17.63 Tg C compared to an increase of 16.38 Tg C. (2) The main meteorological factor affecting the NPP of the Inner Mongolia grassland is precipitation, followed by sunshine duration and temperature. About 97.06% of the grassland shows a positive correlation between NPP and precipitation. (3) The results for NPP and its changing trends are not completely consistent in the long- and short-term study periods. Considering the instability of grassland growth, it is necessary to take the periodic variation of precipitation into account when studying NPP. These results could provide basic information for policy formulation and scientific research into the ecological environment management of grassland areas in the future.

In the dual-route language model, the dorsal pathway is known for sound-to-motor mapping, but the role of the ventral stream is controversial. With the goal of enhancing our understanding of language models, this study investigated the diffusion characteristics of candidate tracts in aphasic patients. We evaluated 14 subacute aphasic patients post-stroke and 11 healthy controls with language assessment and diffusion magnetic resonance imaging. Voxel-based lesion-symptom mapping found multiple linguistic associations for the ventral stream, while automated fiber quantification (AFQ) showed, via reduced fractional anisotropy (FA) and axial diffusivity with increased radial diffusivity (all corrected p

BACKGROUND:Inconsistent results have been reported for hyperbaric oxygen therapy (HBO) for acute stroke. We conducted a systematic review and meta-analysis to evaluate the benefit of HBO in animal studies of middle cerebral artery occlusion (MCAO). METHODS:A systematic search of the literature published prior to September 2015 was performed using Embase, Medline (OvidSP), Web of Science and PubMed. Keywords included "hyperoxia" OR "hyperbaric oxygen" OR "HBO" AND "isch(a)emia" OR "focal cerebral ischemia" OR "stroke" OR "infarct" OR "middle cerebral artery occlusion (MCAO)." The primary endpoints were the infarct size and/or neurological outcome score evaluated after HBO treatment in MCAO. Heterogeneity was analyzed using Cochrane Library's RevMan 5.3.5. RESULTS:Fifty-one studies that met the inclusion criteria were identified among the 1198 studies examined. When compared with control group data, HBO therapy resulted in infarct size reduction or improved neurological function (32% decrease in infarct size; 95% confidence interval (CI), range 28%-37%; p < 0.00001). Mortality was 18.4% in the HBO group and 26.7% in the control group (RR 0.72, 95% CI, 0.54-0.98; p = 0.03). Subgroup analysis showed that a maximal neuro-protective effect was reached when HBO was administered immediately after MCAO with an absolute atmospheric pressure (ATA) of 2.0 (50% decrease; 95% CI, 43% -57% decrease; p < 0.0001) and more than 6 hours HBO treatment (53% decrease; 95% CI, 41% -64% decrease; p = 0.0005). CONCLUSIONS:HBO had a neuro-protective effect and improved survival in animal models of MCAO, especially in animals given more than 6 hours of HBO and when given immediately after MCAO with 2.0 ATA.

Engineering ceramics have been widely used in modern industry for their excellent physical and mechanical properties, and they are difficult to machine owing to their high hardness and brittleness. Electrical discharge machining (EDM) is the appropriate process for machining engineering ceramics provided they are electrically conducting. However, the electrical resistivity of the popular engineering ceramics is higher, and there has been no research on the relationship between the EDM parameters and the electrical resistivity of the engineering ceramics. This paper investigates the effects of the electrical resistivity and EDM parameters such as tool polarity, pulse interval, and electrode material, on the ZnO/Al2O3 ceramic's EDM performance, in terms of the material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). The results show that the electrical resistivity and the EDM parameters have the great influence on the EDM performance. The ZnO/Al2O3 ceramic with the electrical resistivity up to 3410 Ω·cm can be effectively machined by EDM with the copper electrode, the negative tool polarity, and the shorter pulse interval. Under most machining conditions, the MRR increases, and the SR decreases with the decrease of electrical resistivity. Moreover, the tool polarity, and pulse interval affect the EWR, respectively, and the electrical resistivity and electrode material have a combined effect on the EWR. Furthermore, the EDM performance of ZnO/Al2O3 ceramic with the electrical resistivity higher than 687 Ω·cm is obviously different from that with the electrical resistivity lower than 687 Ω·cm, when the electrode material changes. The microstructure character analysis of the machined ZnO/Al2O3 ceramic surface shows that the ZnO/Al2O3 ceramic is removed by melting, evaporation and thermal spalling, and the material from the working fluid and the graphite electrode can transfer to the workpiece surface during electrical discharge machining ZnO/Al2O3 ceramic.

Here, we study the old problem of why identical insulators can charge one another on contact. We perform several experiments showing that, if driven by a preexisting electric field, charge is transferred between contacting insulators. This transfer happens because the insulator surfaces adsorb small amounts of water from a humid atmosphere. We believe the electric field then separates positively from negatively charged ions prevailing within the water, which we believe to be hydronium and hydroxide ions, such that at the point of contact, positive ions of one insulator neutralize negative ions of the other one, charging both of them. This mechanism can explain for the first time the observation made four decades ago that wind-blown sand discharges in sparks if and only if a thunderstorm is nearby.