2,729 research outputs found
Characterization of a 60S complex of the adenomatous polyposis coli tumor suppressor protein
AbstractThe tumor suppressor protein adenomatous polyposis coli (APC) is a multifunctional protein with a well characterized role in the Wnt signal transduction pathway and roles in cytoskeletal regulation and cell polarity. The soluble pool of APC protein in colon epithelial tumor cells exists in two distinct complexes fractionating at ∼20S and ∼60S in size. The 20S complex contains components of the β-catenin destruction complex and probably functions in the Wnt pathway. In this study, we characterized the molecular nature of the 60S APC- containing complex by examining known potential binding partners of APC. 60S APC did not contain EB1 or diaphanous, proteins that have been reported to interact with APC and are implicated in microtubule plus end stabilization. Nor did the two other microtubule associated proteins, MAP4 or KAP3, which is thought to link APC to kinesin motor proteins, associate with the 60S complex. Minor fractions of α-tubulin, γ-tubulin and IQGAP1, a Rac1 and CDC42 effector that interacts with APC, specifically associated with APC in the 60S fraction. We propose that 60S APC is a discrete high molecular weight complex with a novel function in cytoskeletal regulation in epithelial cells apart from its well established role in targeting catenin destruction or its proposed role in microtubule plus end stabilization
UNSTEADY MHD THREE DIMENSIONAL FLOW OF MAXWELL FLUID THROUGH POROUS MEDIUM IN A PARALLEL PLATE CHANNEL UNDER THE INFLUENCE OF INCLINED MAGNETIC FIELD
In this paper, we discuss the unsteady hydro magnetic flow of an electrically conducting Maxwell fluid in a parallel plate channel bounded by porous medium under the influence of a uniform magnetic field of strength Ho inclined at an angle of inclination with the normal to the boundaries. The perturbations are created by a constant pressure gradient along the plates. The time required for the transient state to decay and the ultimate steady state solution are discussed in detail. The exact solutions for the velocity of the Maxwell fluid consists of steady state are analytically derived, its behaviour computationally discussed with reference to the various governing parameters with the help of graphs. The shear stresses on the boundaries are also obtained analytically and their behaviour is computationally discussed in detail
A two dimensional model for ferromagnetic martensites
We consider a recently introduced 2-D square-to-rectangle martensite model
that explains several unusual features of martensites to study ferromagnetic
martensites. The strain order parameter is coupled to the magnetic order
parameter through a 4-state clock model. Studies are carried out for several
combinations of the ordering of the Curie temperatures of the austenite and
martensite phases and, the martensite transformation temperature. We find that
the orientation of the magnetic order which generally points along the short
axis of the rectangular variant, changes as one crosses the twin or the
martensite-austenite interface. The model shows the possibility of a subtle
interplay between the growth of strain and magnetic order parameters as the
temperature is decreased. In some cases, this leads to qualitatively different
magnetization curves from those predicted by earlier mean field models.
Further, we find that strain morphology can be substantially altered by the
magnetic order. We have also studied the dynamic hysteresis behavior.
The corresponding dissipation during the forward and reverse cycles has
features similar to the Barkhausen's noise.Comment: 9 pages, 11 figure
Design and Implementation of A PV Powered Five Level Inverter Using Multilevel Differential Boost Converter
ABSTRACT: The conventional power conditioning units require a DC-DC converter followed by an inverter circuit to deliver the required power to the load. This increases the required power conversion stages, system cost, size and reduces the overall system efficiency. This paper presents a boost converter topology that provides DC-AC conversion along with voltage boosting in a single stage. The multi level differential boost converter topology consists of two boost converters connected back to back with a voltage boosting function. Multi level differential boost converter topology requires less power conversion stages and reduces the size of power conditioning units. This converter topology can be employed in uninterruptible power supplies and AC drives. With the differential boost converter topology, a ripple free pure sinusoidal wave can be obtained. The differential boost converter topology provides a multi level output along with voltage boosting by employing a single DC voltage source. The design and analysis of multi level differential boost converter have been done
Low energy excitations in crystalline perovskite oxides: Evidence from noise experiments
In this paper we report measurements of 1/f noise in a crystalline metallic
oxide with perovskite structure down to 4.2K. The results show existence of
localized excitations with average activation energy 70-80 meV which
produce peak in the noise at T 35-40K. In addition, it shows clear
evidence of tunnelling type two-level-systems (as in glasses) which show up in
noise measurements below 30K.Comment: 11 pages, 4 figures, to appear in Phys Rev B, vol 58, 1st Dec issu
Effect of Pseudomonas fluorescens (IISR-6) and Trichoderma harzianum (P-26) on growth of black pepper (Piper nigrum L.) in the nursery
Experiments conducted to study the effect of Pseudomonas fluorescens (IISR-6) and Trichoderma harzinaum (P-26) on growth of black pepper (Piper nigrum) rooted cuttings in the nursery indicated that maximum height and leaf area of cuttings were obtained with application of P. fluorescens thrice, which was on par with raising cuttings in T. harzianum applied potting mixture and application of P. fluorescens thrice. Number of roots and biomass production were higher with combined application of P. fluorescens (thrice) and T. harzianum which was on par with application of P. fluorescens thrice.
 
Caregiver perceptions of change in pediatric asthma control during the COVID-19 pandemic
PURPOSE: Although several indicators suggest that pediatric asthma control in the United States improved early in the pandemic, other indicators suggest not. Missing are reports from caregivers of the experiences of their children with asthma early in the pandemic.
METHODS: Using the PP-ACT and other measures that we specifically constructed for our research, we conducted a cross-sectional national survey of US caregivers of children with asthma (N=595) to examine perceived change in their child\u27s asthma control and changes in reports of ED visits and use of emergency relief medicine and controller medicine pre-pandemic (January to March 2020) versus early-pandemic (June to September 2020).
RESULTS: Caregivers fell into three groups: most caregivers perceived that their child\u27s asthma control was improved (50.3%) or unchanged (41.2%), and few reported worse control (8.5%). Surprisingly, all three groups of caregivers reported similar frequencies of early-pandemic and pre-pandemic ED visits and use of emergency relief medicine. Also surprising, caregivers who perceived their child\u27s asthma as more controlled (compared with the other two groups) reported more frequent ED visits and use of emergency relief medicine, yet also more use of controller medicine at both early-pandemic and pre-pandemic.
CONCLUSION: The mismatch between caregivers\u27 perceptions of their child\u27s early-pandemic asthma control and their reports of ED visits and use of emergency relief medicine suggests that caregivers may rely on a gist (a global evaluation that can include nonbiomedical evidence) when estimating their child\u27s asthma control. Caregivers and their families could benefit from help from clinicians in understanding the discrepancy between subjective asthma control and asthma control indicators and in understanding what well-controlled asthma looks and feels like
Exploring caregiver interest in and preferences for interventions for children with risk of asthma exacerbation: Web-based survey
BACKGROUND: Maintaining control of asthma symptoms is the cornerstone of asthma treatment guidelines in the United States. However, suboptimal asthma control and asthma exacerbations among young people are common and are associated with many negative outcomes. Interventions to improve asthma control are needed. For such interventions to be successful, it is necessary to understand the types of interventions that are appealing to caregivers of children with different levels of risk of exacerbation.
OBJECTIVE: This study aimed to evaluate whether caregivers of children with high (vs low) risk of asthma exacerbation show different levels of interest in and preferences for potential intervention programs and delivery methods.
METHODS: We contracted with Ipsos to administer a web-based survey to caregivers of children with asthma who were residing in the United States. Caregivers (N=394) reported their interest (1=not at all; 3=a lot) in 9 possible intervention programs and 8 possible intervention delivery methods. Caregivers also indicated their preferences by selecting the 3 intervention programs and 3 delivery methods that most interested them. Finally, caregivers completed 2 open-ended questions asking what other resources might be useful for managing their children\u27s asthma. We classified children as having a high risk of exacerbation if they had an exacerbation in the past 3 months (n=116) and a low risk of exacerbation if otherwise (n=278).
RESULTS: Caregivers reported higher levels of interest in all intervention programs and delivery methods if they cared for a child with a high risk rather than a low risk of exacerbation. However, regardless of the child\u27s risk status, caregivers expressed the highest levels of interest in programs to increase their child\u27s self-management skills, to help pay for asthma care, and to work with the school to manage asthma. Caregivers expressed the highest levels of interest in delivery methods that maintained personal control over accessing information (websites, videos, printed materials, and smartphone apps). Caregivers\u27 preferences were consistent with their interests; programs and delivery methods that were rated as high in interest were also selected as one of the 3 that most interested them. Although most caregivers did not provide additional suggestions for the open-ended questions, a few caregivers suggested intervention programs and delivery methods that we had not included (eg, education about avoiding triggers and medication reminders).
CONCLUSIONS: Similar interests and preferences among caregivers of children with high and low risk of exacerbation suggest a broad need for support in managing childhood asthma. Providers could help caregivers by directing them toward resources that make asthma care more affordable and by helping their children with asthma self-management. Interventions that accommodate caregivers\u27 concerns about having personal control over access to asthma information are likely to be more successful than interventions that do not
Adaptive Mobile Health Intervention for Adolescents with Asthma: Iterative User-Centered Development
Background:
Adolescents diagnosed with persistent asthma commonly take less than 50% of their prescribed inhaled corticosteroids (ICS), placing them at risk for asthma-related morbidity. Adolescents’ difficulties with adherence occur in the context of normative developmental changes (eg, increased responsibility for disease management) and rely upon still developing self-regulation and problem-solving skills that are integral for asthma self-management. We developed an adaptive mobile health system, Responsive Asthma Care for Teens (ReACT), that facilitates self-regulation and problem-solving skills during times when adolescents’ objectively measured ICS adherence data indicate suboptimal rates of medication use.
Objective:
The current paper describes our user-centered and evidence-based design process in developing ReACT. We explain how we leveraged a combination of individual interviews, national crowdsourced feedback, and an advisory board comprised of target users to develop the intervention content.
Methods:
We developed ReACT over a 15-month period using one-on-one interviews with target ReACT users (n=20), national crowdsourcing (n=257), and an advisory board (n=4) to refine content. Participants included 13-17–year-olds with asthma and their caregivers. A total of 280 adolescents and their caregivers participated in at least one stage of ReACT development.
Results:
Consistent with self-regulation theory, adolescents identified a variety of salient intrapersonal (eg, forgetfulness, mood) and external (eg, changes in routine) barriers to ICS use during individual interviews. Adolescents viewed the majority of ReACT intervention content (514/555 messages, 93%) favorably during the crowdsourcing phase, and the advisory board helped to refine the content that did not receive favorable feedback during crowdsourcing. Additionally, the advisory board provided suggestions for improving additional components of ReACT (eg, videos, message flow).
Conclusions:
ReACT involved stakeholders via qualitative approaches and crowdsourcing throughout the creation and refinement of intervention content. The feedback we received from participants largely supported ReACT’s emphasis on providing adaptive and personalized intervention content to facilitate self-regulation and problem-solving skills, and the research team successfully completed the recommended refinements to the intervention content during the iterative development process
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