92 research outputs found

    Welding the Space Station Common Module Prototype

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    The NASA Manned Space Flight program planned for the 1990\u27 s is directed towards the commercial use of space through development of large space structures serving a variety of missions. The diversity of the program, and the demands of the mission tasks requires a thorough understanding of the mission requirements and the requirements for subsystems which are readily adaptable to a wide range of applications. The heart of the NASA Space Station is the common module; a light weight, thin walled pressure vessel that can be configured for a wide range of functions: i.e., laboratories, manufacturing facilities, living quarters, and cargo carriers. Before the space station is placed in orbit, development articles must be built and tested, design issues must be resolved, manufacturing problems overcome and accurate cost information generated

    Neurological manifestations of COVID-19 in adults and children

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    Different neurological manifestations of coronavirus disease 2019 (COVID-19) in adults and children and their impact have not been well characterized. We aimed to determine the prevalence of neurological manifestations and in-hospital complications among hospitalized COVID-19 patients and ascertain differences between adults and children. We conducted a prospective multicentre observational study using the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) cohort across 1507 sites worldwide from 30 January 2020 to 25 May 2021. Analyses of neurological manifestations and neurological complications considered unadjusted prevalence estimates for predefined patient subgroups, and adjusted estimates as a function of patient age and time of hospitalization using generalized linear models. Overall, 161 239 patients (158 267 adults; 2972 children) hospitalized with COVID-19 and assessed for neurological manifestations and complications were included. In adults and children, the most frequent neurological manifestations at admission were fatigue (adults: 37.4%; children: 20.4%), altered consciousness (20.9%; 6.8%), myalgia (16.9%; 7.6%), dysgeusia (7.4%; 1.9%), anosmia (6.0%; 2.2%) and seizure (1.1%; 5.2%). In adults, the most frequent in-hospital neurological complications were stroke (1.5%), seizure (1%) and CNS infection (0.2%). Each occurred more frequently in intensive care unit (ICU) than in non-ICU patients. In children, seizure was the only neurological complication to occur more frequently in ICU versus non-ICU (7.1% versus 2.3%, P < 0.001). Stroke prevalence increased with increasing age, while CNS infection and seizure steadily decreased with age. There was a dramatic decrease in stroke over time during the pandemic. Hypertension, chronic neurological disease and the use of extracorporeal membrane oxygenation were associated with increased risk of stroke. Altered consciousness was associated with CNS infection, seizure and stroke. All in-hospital neurological complications were associated with increased odds of death. The likelihood of death rose with increasing age, especially after 25 years of age. In conclusion, adults and children have different neurological manifestations and in-hospital complications associated with COVID-19. Stroke risk increased with increasing age, while CNS infection and seizure risk decreased with age

    Can an outdoor learning environment improve children’s academic attainment? A quasi-experimental mixed methods study in Bangladesh

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    The present study adopted a quasi-experimental mixed method approach to investigate the influence of an improved school ground on children’s academic performance. In total, 123 children from two (intervention and control) primary schools in Bangladesh participated. In the intervention school, a barren school ground was redesigned with several behavior settings (e.g., gardens and amphitheater) for teaching and learning. Treatment group children (n = 29) received math and science classes outdoors, while a comparison group (n = 32) received usual indoor classes. A control school with no changes to the outdoor environment was included (n = 62). The redesigned school ground was associated with higher levels of academic attainment. Furthermore, all intervention schoolchildren perceived more opportunities to explore in the redesigned school ground. Qualitative insights suggest the diverse settings provided more opportunities to explore, experiment, and work collaboratively. These results highlight the potential for school ground design to contribute to improvement of children’s academic attainment in developing countries

    Hemorrhage and thrombosis in COVID-19-patients supported with extracorporeal membrane oxygenation: an international study based on the COVID-19 critical care consortium

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    Background: Extracorporeal membrane oxygenation (ECMO) is a rescue therapy in patients with severe acute respiratory distress syndrome (ARDS) secondary to COVID-19. While bleeding and thrombosis complicate ECMO, these events may also occur secondary to COVID-19. Data regarding bleeding and thrombotic events in COVID-19 patients on ECMO are sparse. Methods: Using the COVID-19 Critical Care Consortium database, we conducted a retrospective analysis on adult patients with severe COVID-19 requiring ECMO, including centers globally from 01/2020 to 06/2022, to determine the risk of ICU mortality associated with the occurrence of bleeding and clotting disorders. Results: Among 1,248 COVID-19 patients receiving ECMO support in the registry, coagulation complications were reported in 469 cases (38%), among whom 252 (54%) experienced hemorrhagic complications, 165 (35%) thrombotic complications, and 52 (11%) both. The hazard ratio (HR) for Intensive Care Unit mortality was higher in those with hemorrhagic-only complications than those with neither complication (adjusted HR = 1.60, 95% CI 1.28–1.99, p < 0.001). Death was reported in 617 of the 1248 (49.4%) with multiorgan failure (n = 257 of 617 [42%]), followed by respiratory failure (n = 130 of 617 [21%]) and septic shock [n = 55 of 617 (8.9%)] the leading causes. Conclusions: Coagulation disorders are frequent in COVID-19 ARDS patients receiving ECMO. Bleeding events contribute substantially to mortality in this cohort. However, this risk may be lower than previously reported in single-nation studies or early case reports. Trial registration ACTRN12620000421932 (https://covid19.cochrane.org/studies/crs-13513201)

    Sex differences in post-acute neurological sequelae of SARS-CoV-2 and symptom resolution in adults after COVID-19 hospitalization: an international multicenter prospective observational study

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    Although it is known that coronavirus disease 2019 can present with a range of neurological manifestations and in-hospital complications, sparse data exist on whether these initial neurological symptoms of coronavirus disease 2019 are closely associated with post-acute neurological sequelae of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2; PANSC) and whether female versus male sex impacts symptom resolution. In this international, multi-centre, prospective, observational study across 407 sites from 15 countries (30 January 2020 to 30 April 2022), we report the prevalence and risk factors of PANSC among hospitalized adults and investigate the differences between males and females on neurological symptom resolution over time. PANSC symptoms included altered consciousness/confusion, fatigue/malaise, anosmia, dysgeusia and muscle ache/joint pain, on which information was collected at index hospitalization and during follow-up assessments. The analysis considered a time to the resolution of individual and all neurological symptoms. The resulting times were modelled by Weibull regression, assuming mixed-case interval censoring, with sex and age included as covariates. The model results were summarized as cumulative probability functions and age-adjusted and sex-adjusted median times to resolution. We included 6862 hospitalized adults with coronavirus disease 2019, who had follow-up assessments. The median age of the participants was 57 years (39.2% females). Males and females had similar baseline characteristics, except that more males (versus females) were admitted to the intensive care unit (30.5 versus 20.3%) and received mechanical ventilation (17.2 versus 11.8%). Approximately 70% of patients had multiple neurological symptoms at the first follow-up (median = 102 days). Fatigue (49.9%) and myalgia/arthralgia (45.2%) were the most prevalent symptoms of PANSC at the initial follow-up. The reported prevalence in females was generally higher (versus males) for all symptoms. At 12 months, anosmia and dysgeusia were resolved in most patients, although fatigue, altered consciousness and myalgia remained unresolved in >10% of the cohort. Females had a longer time to the resolution (5.2 versus 3.4 months) of neurological symptoms at follow-up for those with more than one neurological symptom. In the multivariable analysis, males were associated with a shorter time to the resolution of symptoms (hazard ratio = 1.53; 95% confidence interval = 1.39–1.69). Intensive care unit admission was associated with a longer time to the resolution of symptoms (hazard ratio = 0.68; 95% confidence interval = 0.60–0.77). Post-discharge stroke was uncommon (0.3% in females and 0.5% in males). Despite the methodological challenges involved in the collection of survey data, this international multi-centre prospective cohort study demonstrated that PANSC following index hospitalization was high. Symptom prevalence was higher and took longer to resolve in females than in males. This supported the fact that while males were sicker during acute illness, females were disproportionately affected by PANSC

    Sex differences in post-acute neurological sequelae of SARS-CoV-2 and symptom resolution in adults after COVID-19 hospitalization: An international multicenter prospective observational study

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    Although it is known that COVID-19 can present with a range of neurological manifestations and in-hospital complications, sparse data exist if these initial neurological symptoms of COVID-19 are closely associated with post-acute neurological sequelae of SARS-CoV-2 (PANSC) and if female versus male sex impacts the symptom resolution. In this international, multicentre, prospective observational study across 407 sites from 15 countries (January/30th/2020-April/30th/2022), we report the prevalence and risk factors of PANSC among hospitalized adults and investigate the differences between males and females on neurological symptom resolution over time. PANSC included altered consciousness/confusion, fatigue/malaise, anosmia, dysgeusia, and muscle aches/joint pain, which were collected at the index hospitalization and during the follow-up assessments. The analysis considered time to resolution of individual and all neurological symptoms. Resulting times were modeled by Weibull regression, assuming mixed-case interval censoring, with sex and age included as covariates. Model results were summarized as cumulative probability functions and age- and sex-adjusted median times to resolution. We included 6,862 hospitalized adults with COVID-19, who had follow-up assessments. The median age of participants was 57 years (39.2% females). Males and females had similar baseline characteristics except that more males (vs. females) were admitted to Intensive Care Unit (30.5% vs. 20.3%) and received mechanical ventilation (17.2% vs. 11.8%). Approximately 70% of patients had multiple neurological symptoms at the first follow-up (median=102 days). Fatigue (49.9%) and myalgia/arthralgia (45.2%) were the most prevalent symptoms of PANSC at the initial follow-up. Reported prevalence in females was generally higher (vs. males) for all symptoms. At 12 months, anosmia and dysgeusia were resolved in most patients, though fatigue, altered consciousness, and myalgia remained unresolved in &gt;10% of the cohort. Females had a longer time to resolution (5.2 vs. 3.4 months) of neurological symptoms at follow-up for those with more than one neurological symptom. In multivariable analysis, males were associated with a shorter time to resolution of symptoms (Hazard Ratio=1.53; 95% Confidence Interval =1.39–1.69). Intensive Care Unit admission was associated with a longer time to the resolution of symptoms (Hazard Ratio =0.68; 95% Confidence Interval=0.60–0.77). Post-discharge stroke was uncommon (0.3% in females; 0.5% in males). Despite the methodological challenges of survey data, this international multicentre prospective cohort study demonstrates that PANSC following index hospitalization is high. Symptom prevalence was higher and took longer to resolve in females than in males. This supports that whilst males were sicker during acute illness, females were disproportionately affected by PANSC

    A combined functional and structural genomics approach identified an EST-SSR marker with complete linkage to the Ligon lintless-2 genetic locus in cotton (Gossypium hirsutum L.)

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    <p>Abstract</p> <p>Background</p> <p>Cotton fiber length is an important quality attribute to the textile industry and longer fibers can be more efficiently spun into yarns to produce superior fabrics. There is typically a negative correlation between yield and fiber quality traits such as length. An understanding of the regulatory mechanisms controlling fiber length can potentially provide a valuable tool for cotton breeders to improve fiber length while maintaining high yields. The cotton (<it>Gossypium hirsutum </it>L.) fiber mutation Ligon lintless-2 is controlled by a single dominant gene (<it>Li<sub>2</sub></it>) that results in significantly shorter fibers than a wild-type. In a near-isogenic state with a wild-type cotton line, <it>Li<sub>2 </sub></it>is a model system with which to study fiber elongation.</p> <p>Results</p> <p>Two near-isogenic lines of Ligon lintless-2 (<it>Li<sub>2</sub></it>) cotton, one mutant and one wild-type, were developed through five generations of backcrosses (BC<sub>5</sub>). An F<sub>2 </sub>population was developed from a cross between the two <it>Li<sub>2 </sub></it>near-isogenic lines and used to develop a linkage map of the <it>Li<sub>2 </sub></it>locus on chromosome 18. Five simple sequence repeat (SSR) markers were closely mapped around the <it>Li<sub>2 </sub></it>locus region with two of the markers flanking the <it>Li<sub>2 </sub></it>locus at 0.87 and 0.52 centimorgan. No apparent differences in fiber initiation and early fiber elongation were observed between the mutant ovules and the wild-type ones. Gene expression profiling using microarrays suggested roles of reactive oxygen species (ROS) homeostasis and cytokinin regulation in the <it>Li<sub>2 </sub></it>mutant phenotype. Microarray gene expression data led to successful identification of an EST-SSR marker (NAU3991) that displayed complete linkage to the <it>Li<sub>2 </sub></it>locus.</p> <p>Conclusions</p> <p>In the field of cotton genomics, we report the first successful conversion of gene expression data into an SSR marker that is associated with a genomic region harboring a gene responsible for a fiber trait. The EST-derived SSR marker NAU3991 displayed complete linkage to the <it>Li<sub>2 </sub></it>locus on chromosome 18 and resided in a gene with similarity to a putative plectin-related protein. The complete linkage suggests that this expressed sequence may be the <it>Li<sub>2 </sub></it>gene.</p

    Distinctive features of the microbiota associated with different forms of apical periodontitis

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    Microorganisms infecting the dental root canal system play an unequivocal role as causative agents of apical periodontitis. Although fungi, archaea, and viruses have been found in association with some forms of apical periodontitis, bacteria are the main microbial etiologic agents of this disease. Bacteria colonizing the root canal are usually organized in communities similar to biofilm structures. Culture and molecular biology technologies have demonstrated that the endodontic bacterial communities vary in species richness and abundance depending on the different types of infection and different forms of apical periodontitis. This review paper highlights the distinctive features of the endodontic microbiota associated with diverse clinical conditions
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