Integrated self-healing thermal protection for high-speed vehicles

Please click Additional Files below to see the full abstract

Endoscopic rhizotomy for chronic lumbar zygapophysial joint pain.

BACKGROUND: Chronic lumbar zygapophysial joint pain is a common cause of chronic low back pain. Percutaneous radiofrequency ablation (RFA) is one of the effective management options; however, the results from the traditional RFA need to be improved in certain cases. The aim of this study is to investigate the effect of percutaneous radiofrequency ablation under endoscopic guidance (ERFA) for chronic low back pain secondary to facet joint arthritis. METHODS: This is a prospective study enrolled 60 patients. The cases were randomized into two groups: 30 patients in the control group underwent traditional percutaneous radiofrequency ablation, others underwent ERFA. The lumbar visual analog scale (VAS), MacNab score, and postoperative complications were used to evaluate the outcomes. All outcome assessments were performed at postoperative 1 day, 1 month, 3 months, 6 months, and 12 months. RESULTS: There was no difference between the two groups in preoperative VAS (P \u3e 0.05). VAS scores, except the postoperative first day, in all other postoperative time points were significantly lower than preoperative values each in both groups (P \u3c 0.05). There was no significant difference between the two groups in VAS at 1 day, 1 month, and 3 months after surgery (P \u3e 0.05). However, the EFRA demonstrated significant benefits at the time points of 3 months and 6 months (P \u3e 0.05). The MacNab scores of 1-year follow-up in the ERFA group were higher than that in the control group (P \u3c 0.05). The incidence of complications in the ERFA group was significantly less than that in the control group (P \u3c 0.05). CONCLUSIONS: ERFA may achieve more accurate and definite denervation on the nerves, which leads to longer lasting pain relief

Fabrication of Lightweight Radiation Shielding Composite Materials by Field Assisted Sintering Technique (FAST)

Advances in radiation shielding technologies are needed to protect humans and electronic components from all threats of space radiation over long durations. In this paper, we report on the use of the innovative and novel fabrication technology known as Field Assisted Sintering Technology (FAST) to fabricate lightweight material with enhanced radiation shielding strength to safeguard humans and electronics suitable for next generation space exploration missions. The base materials we investigated were aluminum (Al), the current standard material for space hardware, and Ultra-High Molecular Weight Polyethylene (UHMWPE), which has high hydrogen content and resistance to nuclear reaction from neutrons, making it a good shielding material for both gamma radiation and particles. UHMWPE also has high resistance to corrosive chemicals, extremely low moisture sensitivity, very low coefficient of friction, and high resistance to abrasion. We reinforced the base materials by adding high density (ie, high atomic weight) metallic material into the composite. These filler materials included: boron carbide (B4C), tungsten (W), tungsten carbide (WC) and gadolinium (Gd)

Reactive Laser Synthesis of Ultra-high-temperature Ceramics HfC, ZrC, TiC, HfN, ZrN, and TiN for Additive Manufacturing

Ultra-high-temperature ceramics (UHTCs) are optimal structural materials for applications that require extreme temperature resilience, resistance to chemically aggressive environments, wear, and mechanical stress. Processing UHTCs with laser-based additive manufacturing (AM) has not been fully realized due to a variety of obstacles. In this work, selective laser reaction sintering (SLRS) techniques were investigated for the production of near net-shape UHTC ceramics such as HfC, ZrC, TiC, HfN, ZrN, and TiN. Group IV transition metal and metal oxide precursor materials were chemically converted and reaction-bonded into layers of UHTCs using single-step selective laser processing in CH4 or NH3 gas that might be compatible with prevailing powder bed fusion techniques. Conversion of either metals (Hf, Zr and Ti) or metal oxides (HfO2, ZrO2, and TiO2) particles was first investigated to examine reaction mechanisms and volume changes associated with SLRS of single-component precursor systems. SLRS processing of metal or metal oxide alone produced near stoichiometric UHTC phases with yields up to 100 wt% total for carbides and nitrides. However, for single component precursors, gas-solid reactivity induced volumetric changes resulted in residual stresses and cracking in the product layer. To mitigate conversion-induced stresses, composite metal/metal oxide precursors were employed to compensate for the volume changes of either the metal (which expands during conversion) or the metal oxide precursor (which contracts).Comment: 58 pages, 17 figure

Vocalisation repertoire at the end of the first year of life: an exploratory comparison of Rett syndrome and typical development

Rett syndrome (RTT) is a rare, late detected developmental disorder associated with severe deficits in the speech-language domain. Despite a few reports about atypicalities in the speech-language development of infants and toddlers with RTT, a detailed analysis of the pre-linguistic vocalisation repertoire of infants with RTT is yet missing. Based on home video recordings, we analysed the vocalisations between 9 and 11 months of age of three female infants with typical RTT and compared them to three age-matched typically developing (TD) female controls. The video material of the infants had a total duration of 424 min with 1655 infant vocalisations. For each month, we (1) calculated the infants’ canonical babbling ratios with CBR(UTTER), i.e., the ratio of number of utterances containing canonical syllables to total number of utterances, and (2) classified their pre-linguistic vocalisations in three non-canonical and four canonical vocalisation subtypes. All infants achieved the milestone of canonical babbling at 9 months of age according to their canonical babbling ratios, i.e. CBR(UTTER) ≥ 0.15. We revealed overall lower CBRs(UTTER) and a lower proportion of canonical pre-linguistic vocalisations consisting of well-formed sounds that could serve as parts of target-language words for the RTT group compared to the TD group. Further studies with more data from individuals with RTT are needed to study the atypicalities in the pre-linguistic vocalisation repertoire which may portend the later deficits in spoken language that are characteristic features of RTT

Automatic vocalisation-based detection of fragile X syndrome and Rett syndrome

Fragile X syndrome (FXS) and Rett syndrome (RTT) are developmental disorders currently not diagnosed before toddlerhood. Even though speech-language deficits are among the key symptoms of both conditions, little is known about infant vocalisation acoustics for an automatic earlier identification of affected individuals. To bridge this gap, we applied intelligent audio analysis methodology to a compact dataset of 4454 home-recorded vocalisations of 3 individuals with FXS and 3 individuals with RTT aged 6 to 11 months, as well as 6 age- and gender-matched typically developing controls (TD). On the basis of a standardised set of 88 acoustic features, we trained linear kernel support vector machines to evaluate the feasibility of automatic classification of (a) FXS vs TD, (b) RTT vs TD, (c) atypical development (FXS+RTT) vs TD, and (d) FXS vs RTT vs TD. In paradigms (a)–(c), all infants were correctly classified; in paradigm (d), 9 of 12 were so. Spectral/cepstral and energy-related features were most relevant for classification across all paradigms. Despite the small sample size, this study reveals new insights into early vocalisation characteristics in FXS and RTT, and provides technical underpinnings for a future earlier identification of affected individuals, enabling earlier intervention and family counselling

Relationship between metabolic syndrome and its components and cardiovascular disease in middle-aged and elderly Chinese population:a national cross-sectional survey

OBJECTIVES: To assess the relationship between metabolic syndrome (MetS) and its components and cardiovascular disease (CVD) according to different criteria of MetS, as well as whether the estimated association between MetS and CVD was affected by different definitions of MetS among the Chinese population. DESIGN: Population-based, cross-sectional study. SETTING: Data were from a large-scale national stroke screening survey, China National Stroke Screening and Prevention Project. PARTICIPANTS: A nationally representative sample of 109 551 Chinese adults aged ≥40 years in 2014-2015 were included. PRIMARY OUTCOME MEASURES: CVD conditions (stroke, coronary heart disease (CHD) and atrial fibrillation (AF)) diagnosed by clinicians were self-reported. RESULTS: ORs after adjusting for CHD, stroke, AF and CVD in those with MetS using the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criterion were 1.56 (95% CI 1.48 to 1.63), 1.23 (95% CI 1.17 to 1.30), 1.14 (95% CI 1.08 to 1.21) and 1.40 (95% CI 1.35 to 1.45); 1.51 (95% CI 1.44 to 1.58), 1.20 (95% CI 1.14 to 1.26), 1.09 (95% CI 1.04 to 1.15) and 1.34 (95% CI 1.29 to 1.38) with the American Heart Association/National Heart, Lung, and Blood Institute criterion; and 1.41 (95% CI 1.35 to 1.48), 1.24 (95% CI 1.19 to 1.30), 1.12 (95% CI 1.06 to 1.18) and 1.31 (95% CI 1.27 to 1.35) with the International Diabetes Federation criterion, respectively. Elevated blood pressures were all highly related to the prevalence of stroke and AF, and reduced high-density lipoprotein-cholesterol was associated with a higher OR for CHD than other individual components of MetS. CONCLUSIONS: MetS is significantly associated with CVD, and the prevalence of CVD was more evident when MetS was defined according to the NCEP ATP III criterion. Developing effective public health strategies for the prevention, detection and treatment of MetS should be an urgent priority to reduce the burden of CVD in China

Materials Design for Hypersonics

Hypersonic vehicles must withstand extreme conditions during flights that exceed five times the speed of sound. This class of vehicles has the potential to facilitate rapid access to space, bolster defense capabilities, and create a new paradigm for transcontinental earth-to-earth travel. However, the extreme aerothermal environments resulting from high Mach number trajectories create significant challenges for vehicle materials and structures. As hypersonic systems advance, there is a critical need to develop novel materials that are resilient to a combination of thermal and mechanical loads, aggressive oxidizing environments, and rapid heating rates. This work aims to provide a succinct discussion of emerging design strategies for refractory alloys, composites, and ceramics used for hypersonic vehicles. We will highlight key design principles for critical vehicle areas such as primary structures, thermal protection, and propulsion systems; the role of theory and computation in elucidating structure-property-processing relationships; and strategies for advancing laboratory scale materials to flight-ready components such as aerostructures and thermal protection systems

Virtual reality and naturalistic developmental behavioral interventions for children with autism spectrum disorder

© 2021 The Author(s).Background: Naturalistic Developmental Behavioral Interventions (NDBI) have been evaluated as the most promising interventions for children with autism spectrum disorder. In recent years, a growing body of literature suggests that technological advancements such as Virtual Reality (VR) are promising intervention tools. However, to the best of our knowledge no studies have combined evidence-based practice with such tools. Aim: This article aims to review the current literature combining NDBI and VR, and provide suggestions on merging NDBI-approaches with VR. Methods: This article is divided into two parts, where we first conduct a review mapping the research applying NDBI-approaches in VR. In the second part we argue how to apply the common features of NDBI into VR-technology. Results: Our findings show that no VR-studies explicitly rely on NDBI-approaches, but some utilize elements in their interventions that are considered to be common features to NDBI. Conclusions and implications: As the results show, to date, no VR-based studies have utilized NDBI in their intervention. We therefore, in the second part of this article, suggests ways to merge VR and NDBI and introduce the term Virtual Naturalistic Developmental Behavioral Interventions (VNDBI). VNDBI is an innovative way of implementing NDBI which will contribute in making interventions more accessible in central as well as remote locations, while reducing unwanted variation between service sites. VNDBI will advance the possibilities of individually tailoring and widen the area of interventions. In addition, VNDBI can provide the field with new knowledge on effective components enhancing the accuracy in the intervention packages and thus move forward the research field and clinical practice.publishedVersio

Clinical Implications of the General Movement Optimality Score:Beyond the Classes of Rasch Analysis

This article explores the clinical implications of the three different classes drawn from a Rasch analysis of the general movements optimality scores (GMOS) of 383 infants. Parametric analysis of the class membership examines four variables: age of assessment, brain injury presence, general movement patterns, and 2-year-old outcomes. GMOS separated infants with typical (class 3) from atypical development, and further separated cerebral palsy (class 2) from other neurodevelopmental disorders (class 1). Each class is unique regarding its quantitative and qualitative representations on the four variables. The GMOS has strong psychometric properties and provides a quantitative measure of early motor functions. The GMOS can be confidently used to assist with early diagnosis and predict distinct classes of developmental outcomes, grade motor behaviors, and provide a solid base to study individual general movement developmental trajectories