926 research outputs found
Endoscopic Management of Pediatric Airway and Esophageal Foreign Bodies
The use of endoscopy is critical to the management of pediatric tracheobronchial and esophageal foreign bodies. Children may present with nonspecific symptoms, and the diagnosis can be difficult when the ingestion or aspiration events go unwitnessed. Advances in endoscopic techniques and the use of optical graspers in the removal of foreign bodies in children have helped decrease morbidity and mortality. In this chapter, the history, clinical presentations, workup, and management for pediatric aerodigestive foreign bodies are discussed
Fully coupled photochemistry of the deuterated ionosphere of Mars and its effects on escape of H and D
Although deuterium (D) on Mars has received substantial attention, the
deuterated ionosphere remains relatively unstudied. This means that we also
know very little about non-thermal D escape from Mars, since it is primarily
driven by excess energy imparted to atoms produced in ion-neutral reactions.
Most D escape from Mars is expected to be non-thermal, highlighting a gap in
our understanding of water loss from Mars. In this work, we set out to fill
this knowledge gap. To accomplish our goals, we use an upgraded 1D
photochemical model that fully couples ions and neutrals and does not assume
photochemical equilibrium. To our knowledge, such a model has not been applied
to Mars previously. We model the atmosphere during solar minimum, mean, and
maximum, and find that the deuterated ionosphere behaves similarly to the
H-bearing ionosphere, but that non-thermal escape on the order of 8000-9000
cms dominates atomic D loss under all solar conditions. The total
fractionation factor, , is --0.07, and integrated water loss is
147--158 m GEL. This is still less than geomorphological estimates. Deuterated
ions at Mars are likely difficult to measure with current techniques due to low
densities and mass degeneracies with more abundant H ions. Future missions
wishing to measure the deuterated ionosphere in situ will need to develop
innovative techniques to do so.Comment: 37 pages, 8 figures, published in Journal of Geophysical Research:
Planet
Muscle Fatigue Analysis Using OpenSim
In this research, attempts are made to conduct concrete muscle fatigue
analysis of arbitrary motions on OpenSim, a digital human modeling platform. A
plug-in is written on the base of a muscle fatigue model, which makes it
possible to calculate the decline of force-output capability of each muscle
along time. The plug-in is tested on a three-dimensional, 29 degree-of-freedom
human model. Motion data is obtained by motion capturing during an arbitrary
running at a speed of 3.96 m/s. Ten muscles are selected for concrete analysis.
As a result, the force-output capability of these muscles reduced to 60%-70%
after 10 minutes' running, on a general basis. Erector spinae, which loses
39.2% of its maximal capability, is found to be more fatigue-exposed than the
others. The influence of subject attributes (fatigability) is evaluated and
discussed
Nonthermal hydrogen loss at Mars: Contributions of photochemical mechanisms to escape and identification of key processes
Hydrogen loss to space is a key control on the evolution of the Martian
atmosphere and the desiccation of the red planet. Thermal escape is thought to
be the dominant loss process, but both forward modeling studies and remote
sensing observations have indicated the presence of a second,
higher-temperature "nonthermal" or "hot" hydrogen component, some fraction of
which also escapes. Exothermic reactions and charge/momentum exchange processes
produce hydrogen atoms with energy above the escape energy, but H loss via many
of these mechanisms has never been studied, and the relative importance of
thermal and nonthermal escape at Mars remains uncertain. Here we estimate
hydrogen escape fluxes via 47 mechanisms, using newly-developed escape
probability profiles. We find that HCO dissociative recombination is the
most important of the mechanisms, accounting for 30-50% of the nonthermal
escape. The reaction CO + H is also important, producing roughly as
much escaping H as momentum exchange between hot O and H. Total nonthermal
escape from the mechanisms considered amounts to 39% (27%) of thermal escape,
for low (high) solar activity. Our escape probability profiles are applicable
to any thermospheric hot H production mechanism and can be used to explore
seasonal and longer-term variations, allowing for a deeper understanding of
desiccation drivers over various timescales. We highlight the most important
mechanisms and suggest that some may be important at Venus, where nonthermal
escape dominates and much of the literature centers on charge exchange
reactions, which do not result in significant escape in this study.Comment: 47 pages, 4 figures, 3 tables. Accepted manuscript. An edited version
of this paper was published by AG
Fatigue evaluation in maintenance and assembly operations by digital human simulation
Virtual human techniques have been used a lot in industrial design in order
to consider human factors and ergonomics as early as possible. The physical
status (the physical capacity of virtual human) has been mostly treated as
invariable in the current available human simulation tools, while indeed the
physical capacity varies along time in an operation and the change of the
physical capacity depends on the history of the work as well. Virtual Human
Status is proposed in this paper in order to assess the difficulty of manual
handling operations, especially from the physical perspective. The decrease of
the physical capacity before and after an operation is used as an index to
indicate the work difficulty. The reduction of physical strength is simulated
in a theoretical approach on the basis of a fatigue model in which fatigue
resistances of different muscle groups were regressed from 24 existing maximum
endurance time (MET) models. A framework based on digital human modeling
technique is established to realize the comparison of physical status. An
assembly case in airplane assembly is simulated and analyzed under the
framework. The endurance time and the decrease of the joint moment strengths
are simulated. The experimental result in simulated operations under laboratory
conditions confirms the feasibility of the theoretical approach
Lumbar muscle size and locations from CT scans of 96 women of age 40 to 63 years
Computed tomography scans of 96 women aged between 40 and 63 years were systematically measured to determine torso muscle moment arms and cross-sectional areas at L2/L3, L3/L4 and L4/L5 disc levels. The major findings were as follows: (1) the mean muscle moment arm and area data were not different bilaterally; (2) psoas, quadratus lumborum, and latissimus dorsi muscle moment arms consistently changed at the three disc levels, while erector spinae, rectus abdominis, transverse abdominis and the oblique muscles remained about the same distance from the three disc centroids; (3) psoas and quadratus lumborum muscles increased in mean size at the lower levels and (4 gross torso anthropometry and body weight had a significant (P r2 from 0[middle dot]12 to 0[middle dot]65) with the size of the erector spinae and psoas muscles, and with the moment arms of the rectus abdominis, transverse abdominis, latissimus dorsi, and oblique muscles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28726/1/0000549.pd
Deep-coverage whole genome sequences and blood lipids among 16,324 individuals.
Large-scale deep-coverage whole-genome sequencing (WGS) is now feasible and offers potential advantages for locus discovery. We perform WGS in 16,324 participants from four ancestries at mean depth >29X and analyze genotypes with four quantitative traits-plasma total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, and triglycerides. Common variant association yields known loci except for few variants previously poorly imputed. Rare coding variant association yields known Mendelian dyslipidemia genes but rare non-coding variant association detects no signals. A high 2M-SNP LDL-C polygenic score (top 5th percentile) confers similar effect size to a monogenic mutation (~30 mg/dl higher for each); however, among those with severe hypercholesterolemia, 23% have a high polygenic score and only 2% carry a monogenic mutation. At these sample sizes and for these phenotypes, the incremental value of WGS for discovery is limited but WGS permits simultaneous assessment of monogenic and polygenic models to severe hypercholesterolemia
Protocol for a statewide randomized controlled trial to compare three training models for implementing an evidence-based treatment
Background: Evidence-based treatments (EBTs) are available for treating childhood behavioral health challenges. Despite EBTs' potential to help children and families, they have primarily remained in university settings. Little empirical evidence exists regarding how specific, commonly used training and quality control models are effective in changing practice, achieving full implementation, and supporting positive client outcomes. Methods/design: This study (NIMH RO1 MH095750; ClinicalTrials.gov Identifier: NCT02543359), which is currently in progress, will evaluate the effectiveness of three training models (Learning Collaborative (LC), Cascading Model (CM), and Distance Education (DE)) to implement a well-established EBT , Parent-Child Interaction Therapy, in real-world, community settings. The three models differ in their costs, skill training, quality control methods, and capacity to address broader implementation challenges. The project is guided by three specific aims: (1) to build knowledge about training outcomes, (2) to build knowledge about implementation outcomes, and (3) to test the differential impact of training clinicians using LC, CM, and DE models on key client outcomes. Fifty (50) licensed psychiatric clinics across Pennsylvania were randomized to one of the three training conditions: (1) LC, (2) CM, or (3) DE. The impact of training on practice skills (clinician level) and implementation/sustainment outcomes (clinic level) are being evaluated at four timepoints coinciding with the training schedule: baseline, 6 (mid), 12 (post), and 24 months (1 year follow-up). Immediately after training begins, parent-child dyads (client level) are recruited from the caseloads of participating clinicians. Client outcomes are being assessed at four timepoints (pre-treatment, 1, 6, and 12 months after the pre-treatment). Discussion: This proposal builds on an ongoing initiative to implement an EBT statewide. A team of diverse stakeholders including state policy makers, payers, consumers, service providers, and academics from different, but complementary areas (e.g., public health, social work, psychiatry), has been assembled to guide the research plan by incorporating input from multidimensional perspective. Trial registration: ClinicalTrials.gov: NCT0254335
- …