340 research outputs found
Development of a Cost-Effective Concrete Bridge Deck Preservation Program: Volume 2—Final Results and Recommendations
The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix with water and enter the deck through cracks and the pore structure of the concrete. This results in corrosion of the reinforcing steel and scaling of the surface, which leads to a shortened bridge deck life and costly deck replacement. The objective of this study is to investigate potentially effective and economic bridge deck preservation methods to significantly extend the service life of bridge decks, and as a result, extend the life of bridge structures in the State of Indiana. The research is presented in two volumes. Volume 1 focuses on the development and implementation of the experimental program. A survey of State Departments of Transportation identified the types of bridge deck preservation programs that are currently in use, the methods that they have employed in the past, and the perceived level of success with these programs and methods. A literature review provided information regarding specific products that performed well, characteristics of broader chemical families and their best uses, and other variables that may influence the effectiveness of sealers. The results of the DOT survey and literature review were used to determine the materials and methods to be further investigated in the experimental study. Based on this background, a series of macrocell specimens were constructed, and a salt water exposure regimen was initiated to examine the effectiveness of deck/crack sealer materials and application methods that were identified. Volume 2 presents the results of this study which were developed through the analysis of the recorded electrical activity after 1600 days of exposure followed by autopsy of the specimens. A visual rating scheme was used to assess the specimens during autopsy and to demonstrate the correspondence between the observed severity of corrosion and the recorded electrical activity. In addition, a deck sealer was applied to specimens with preexisting corrosion to evaluate the sealer\u27s effectiveness in slowing the rate of corrosion. The deck sealer products were studied further by correlating both the sealer penetration depth and the chloride penetration profile with the products\u27 effectiveness in resisting corrosion activity. A preliminary field application of crack sealer to an existing bridge deck was completed to evaluate processes, equipment, and other required resources. Finally, recommendations are provided regarding product selection and application to enable cost effective implementation of a bridge deck sealing program across the State of Indiana
Development of a Cost-Effective Concrete Bridge Deck Preservation Program: Volume 1—Development and Implementation of the Experimental Program
The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix with water and enter the deck through cracks and the pore structure of the concrete. This results in corrosion of the reinforcing steel and scaling of the surface, which leads to a shortened bridge deck life and costly deck replacement. The objective of this study is to investigate potentially effective and economic bridge deck preservation methods to significantly extend the service life of bridge decks, and as a result, extend the life of bridge structures in the State of Indiana. The research is presented in two volumes. Volume 1 focuses on the development and implementation of the experimental program. A survey of State Departments of Transportation identified the types of bridge deck preservation programs that are currently in use, the methods that they have employed in the past, and the perceived level of success with these programs and methods. A literature review provided information regarding specific products that performed well, characteristics of broader chemical families and their best uses, and other variables that may influence the effectiveness of sealers. The results of the DOT survey and literature review were used to determine the materials and methods to be further investigated in the experimental study. Based on this background, a series of macrocell specimens were constructed, and a salt water exposure regimen was initiated to examine the effectiveness of deck/crack sealer materials and application methods that were identified. Volume 2 presents the results of this study which were developed through the analysis of the recorded electrical activity after 1600 days of exposure followed by autopsy of the specimens. A visual rating scheme was used to assess the specimens during autopsy and to demonstrate the correspondence between the observed severity of corrosion and the recorded electrical activity. In addition, a deck sealer was applied to specimens with preexisting corrosion to evaluate the sealer\u27s effectiveness in slowing the rate of corrosion. The deck sealer products were studied further by correlating both the sealer penetration depth and the chloride penetration profile with the products\u27 effectiveness in resisting corrosion activity. A preliminary field application of crack sealer to an existing bridge deck was completed to evaluate processes, equipment, and other required resources. Finally, recommendations are provided regarding product selection and application to enable cost effective implementation of a bridge deck sealing program across the State of Indiana
Genome-Wide TOP2A DNA Cleavage is Biased Toward Translocated and Highly Transcribed Loci
Type II topoisomerases orchestrate proper DNA topology, and they are the targets of anti-cancer drugs that cause treatment-related leukemias with balanced translocations. Here, we develop a high-throughput sequencing technology to define TOP2 cleavage sites at single-base precision, and use the technology to characterize TOP2A cleavage genome-wide in the human K562 leukemia cell line. We find that TOP2A cleavage has functionally conserved local sequence preferences, occurs in cleavage cluster regions (CCRs), and is enriched in introns and lincRNA loci. TOP2A CCRs are biased toward the distal regions of gene bodies, and TOP2 poisons cause a proximal shift in their distribution. We find high TOP2A cleavage levels in genes involved in translocations in TOP2 poison–related leukemia. In addition, we find that a large proportion of genes involved in oncogenic translocations overall contain TOP2A CCRs. The TOP2A cleavage of coding and lincRNA genes is independently associated with both length and transcript abundance. Comparisons to ENCODE data reveal distinct TOP2A CCR clusters that overlap with marks of transcription, open chromatin, and enhancers. Our findings implicate TOP2A cleavage as a broad DNA damage mechanism in oncogenic translocations as well as a functional role of TOP2A cleavage in regulating transcription elongation and gene activation
Minimalistic control of biped walking in rough terrain
Toward our comprehensive understanding of legged locomotion in animals and machines, the compass gait model has been intensively studied for a systematic investigation of complex biped locomotion dynamics. While most of the previous studies focused only on the locomotion on flat surfaces, in this article, we tackle with the problem of bipedal locomotion in rough terrains by using a minimalistic control architecture for the compass gait walking model. This controller utilizes an open-loop sinusoidal oscillation of hip motor, which induces basic walking stability without sensory feedback. A set of simulation analyses show that the underlying mechanism lies in the “phase locking” mechanism that compensates phase delays between mechanical dynamics and the open-loop motor oscillation resulting in a relatively large basin of attraction in dynamic bipedal walking. By exploiting this mechanism, we also explain how the basin of attraction can be controlled by manipulating the parameters of oscillator not only on a flat terrain but also in various inclined slopes. Based on the simulation analysis, the proposed controller is implemented in a real-world robotic platform to confirm the plausibility of the approach. In addition, by using these basic principles of self-stability and gait variability, we demonstrate how the proposed controller can be extended with a simple sensory feedback such that the robot is able to control gait patterns autonomously for traversing a rough terrain.National Science Foundation (U.S.) (grant 0746194)Swiss National Science Foundation (grant PBZH2-114461)Swiss National Science Foundation (grant PP00P2_123387/1
Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and
NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a
quiescent state since at least early 2015, reactivated between 2017 March 19
and April 5. The radio flux density, while variable, is approximately 100x
larger than during its dormant state. The X-ray flux one month after
reactivation was at least 800x larger than during quiescence, and has been
decaying exponentially on a 111+/-19 day timescale. This high-flux state,
together with a radio-derived rotational ephemeris, enabled for the first time
the detection of X-ray pulsations for this magnetar. At 5%, the 0.3-6 keV
pulsed fraction is comparable to the smallest observed for magnetars. The
overall pulsar geometry inferred from polarized radio emission appears to be
broadly consistent with that determined 6-8 years earlier. However, rotating
vector model fits suggest that we are now seeing radio emission from a
different location in the magnetosphere than previously. This indicates a novel
way in which radio emission from magnetars can differ from that of ordinary
pulsars. The torque on the neutron star is varying rapidly and unsteadily, as
is common for magnetars following outburst, having changed by a factor of 7
within six months of reactivation.Comment: Published in ApJ (2018 April 5); 13 pages, 4 figure
The development of videoconference-based support for people living with rare dementias and their carers: Protocol for a 3-phase support group evaluation
Background:
People living with rarer dementias face considerable difficulty accessing tailored information, advice, and peer and professional support. Web-based meeting platforms offer a critical opportunity to connect with others through shared lived experiences, even if they are geographically dispersed, particularly during the COVID-19 pandemic.
Objective:
We aim to develop facilitated videoconferencing support groups (VSGs) tailored to people living with or caring for someone with familial or sporadic frontotemporal dementia or young-onset Alzheimer disease, primary progressive aphasia, posterior cortical atrophy, or Lewy body dementia. This paper describes the development, coproduction, field testing, and evaluation plan for these groups.
Methods:
We describe a 3-phase approach to development. First, information and knowledge were gathered as part of a coproduction process with members of the Rare Dementia Support service. This information, together with literature searches and consultation with experts by experience, clinicians, and academics, shaped the design of the VSGs and session themes. Second, field testing involved 154 Rare Dementia Support members (people living with dementia and carers) participating in 2 rounds of facilitated sessions across 7 themes (health and social care professionals, advance care planning, independence and identity, grief and loss, empowering your identity, couples, and hope and dementia). Third, a detailed evaluation plan for future rounds of VSGs was developed.
Results:
The development of the small groups program yielded content and structure for 9 themed VSGs (the 7 piloted themes plus a later stages program and creativity club for implementation in rounds 3 and beyond) to be delivered over 4 to 8 sessions. The evaluation plan incorporated a range of quantitative (attendance, demographics, and geography; pre-post well-being ratings and surveys; psycholinguistic analysis of conversation; facial emotion recognition; facilitator ratings; and economic analysis of program delivery) and qualitative (content and thematic analysis) approaches. Pilot data from round 2 groups on the pre-post 3-word surveys indicated an increase in the emotional valence of words selected after the sessions.
Conclusions:
The involvement of people with lived experience of a rare dementia was critical to the design, development, and delivery of the small virtual support group program, and evaluation of this program will yield convergent data about the impact of tailored support delivered to geographically dispersed communities. This is the first study to design and plan an evaluation of VSGs specifically for people affected by rare dementias, including both people living with a rare dementia and their carers, and the outcome of the evaluation will be hugely beneficial in shaping specific and targeted support, which is often lacking in this population
Evidence for cognitive vestibular integration impairment in idiopathic scoliosis patients
<p>Abstract</p> <p>Background</p> <p>Adolescent idiopathic scoliosis is characterized by a three-dimensional deviation of the vertebral column and its etiopathogenesis is unknown. Various factors cause idiopathic scoliosis, and among these a prominent role has been attributed to the vestibular system. While the deficits in sensorimotor transformations have been documented in idiopathic scoliosis patients, little attention has been devoted to their capacity to integrate vestibular information for cognitive processing for space perception. Seated idiopathic scoliosis patients and control subjects experienced rotations of different directions and amplitudes in the dark and produced saccades that would reproduce their perceived spatial characteristics of the rotations (vestibular condition). We also controlled for possible alteration of the oculomotor and vestibular systems by measuring the subject's accuracy in producing saccades towards memorized peripheral targets in absence of body rotation and the gain of their vestibulo-ocular reflex.</p> <p>Results</p> <p>Compared to healthy controls, the idiopathic scoliosis patients underestimated the amplitude of their rotations. Moreover, the results revealed that idiopathic scoliosis patients produced accurate saccades to memorized peripheral targets in absence of body rotation and that their vestibulo-ocular reflex gain did not differ from that of control participants.</p> <p>Conclusion</p> <p>Overall, results of the present study demonstrate that idiopathic scoliosis patients have an alteration in cognitive integration of vestibular signals. It is possible that severe spine deformity developed partly due to impaired vestibular information travelling from the cerebellum to the vestibular cortical network or alteration in the cortical mechanisms processing the vestibular signals.</p
Ice and pulsed electromagnetic field to reduce pain and swelling after distal radius fractures
Objective: To examine the relative effectiveness of ice therapy and/or pulsed electromagnetic field in reducing pain and swelling after the immobilization period following a distal radius fracture.Methods: A total of 83 subjects were randomly allocated to receive 30 minutes of either ice plus pulsed electromagnetic field (group A); ice plus sham pulsed electromagnetic field (group B); pulsed electromagnetic field alone (group C), or sham pulsed electromagnetic field treatment for 5 consecutive days (group D). All subjects received a standard home exercise programme. A visual analogue scale was used for recording pain; volumetric displacement for measuring the swelling of the forearm; and a hand-held goniometer for measuring the range of wrist motions before treatment on days 1, 3 and 5.Results: At day 5, a significantly greater cumulative reduction in the visual analogue scores as well as ulnar deviation range of motion was found in group A than the other 3 groups. For volumetric measurement and pronation, participants in group A performed better than subjects in group D but not those in group B.Conclusion: The addition of pulsed electromagnetic field to ice therapy produces better overall treatment outcomes than ice alone, or pulsed electromagnetic field alone in pain reduction and range of joint motion in ulnar deviation and flexion for a distal radius fracture after an immobilization period of 6 weeks.<br /
Bedside Sublingual Video Imaging of Microcirculation in Assessing Bacterial Infection in Cirrhosis
Bacterial infections are common in cirrhosis and can lead to life-threatening complications. Sidestream dark-field (SDF) imaging has recently emerged as a noninvasive tool for capturing real-time video images of sublingual microcirculation in critically ill patients with sepsis. The objective of this study was to assess the utility of SDF in determining underlying infection in patients with cirrhosis. Sublingual microcirculation was compared among patients with compensated cirrhosis (Group A, n = 13), cirrhosis without sepsis (Group B, n = 18), cirrhosis with sepsis (Group C, n = 14), and sepsis only (Group D, n = 10). The blood flow was semi-quantitatively evaluated in four equal quadrants in small (10–25 mm); medium (26–50 mm); and large (51–100 mm) sublingual capillaries. The blood flow was described as no flow (0), intermittent flow (1), sluggish flow (2), and continuous flow (3). The overall flow score or microvascular flow index (MFI) was measured for quantitative assessment of microcirculation and predicting power for concurrent infection in cirrhosis. Marked impairment was observed at all levels of microvasculature in Groups B and C when compared with Group A. This effect was restricted to small vessels only when Group B was compared with Group C. MFI < 1.5 was found to have highest sensitivity (100%) and specificity (100%) for infection in decompensated cirrhosis. SDF imaging of sublingual microcirculation can be a useful bedside diagnostic tool to assess bacterial infection in cirrhosis
Efficacy of motor imagery in post-stroke rehabilitation: a systematic review
BACKGROUND: Evaluation of how Motor Imagery and conventional therapy (physiotherapy or occupational therapy) compare to conventional therapy only in their effects on clinically relevant outcomes during rehabilitation of persons with stroke. DESIGN: Systematic review of the literature METHODS: We conducted an electronic database search in seven databases in August 2005 and also hand-searched the bibliographies of studies that we selected for the review.Two reviewers independently screened and selected all randomized controlled trials that compare the effects of conventional therapy plus Motor Imagery to those of only conventional therapy on stroke patients.The outcome measurements were: Fugl-Meyer Stroke Assessment upper extremity score (66 points) and Action Research Arm Test upper extremity score (57 points).Due to the high variability in the outcomes, we could not pool the data statistically. RESULTS: We identified four randomized controlled trials from Asia and North America. The quality of the included studies was poor to moderate. Two different Motor imagery techniques were used (three studies used audiotapes and one study had occupational therapists apply the intervention). Two studies found significant effects of Motor Imagery in the Fugl-Meyer Stroke Assessment: Differences between groups amounted to 11.0 (1.0 to 21.0) and 3.2 (-4 to 10.3) respectively and in the Action Research Arm Test 6.1 (-6.2 to 18.4) and 15.8 (0.5 to 31.0) respectively. One study did not find a significant effect in the Fugl-Meyer Stroke Assessment and Color trail Test (p = 0.28) but in the task-related outcomes (p > 0.001). CONCLUSION: Current evidence suggests that Motor imagery provides additional benefits to conventional physiotherapy or occupational therapy. However, larger and methodologically sounder studies should be conducted to assess the benefits of Motor imagery
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