Models of high rank for weakly scattered theories

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2006.Includes bibliographical references (leaves 32-33).The Scott rank of a countable structure A, denoted sr(A), was observed by Nadel to be at most wA + 1, where wA4 is the least ordinal not recursive in A. Let T be weakly scattered and L(a,T) be E2-admissible. We give a sufficient condition, the B,-hypothesis, under which T has model A with w4A = a and sr(A) = a + 1. Given the B,-hypothesis, an iterated forcing argument is used to obtain a generic Ta D T such that Th has a model with the desired properties.by Alice Shih Ying Chan.Ph.D

Evidence from Two Large Field Experiments that Peer Comparison Feedback Can Reduce Residential Energy Usage

By providing feedback to customers on home electricity and natural gas usage with a focus on peer comparisons, utilities can reduce energy consumption at a low cost. We analyze data from two large-scale, random-assignment field experiments conducted by utility companies providing electricity (the Sacramento Municipal Utility District (SMUD)) and electricity and natural gas (Puget Sound Energy (PSE)), in partnership with a private company, Positive Energy/oPower, which provides monthly or quarterly mailed peer feedback reports to customers. We find reductions in energy consumption of 1.2% (PSE) to 2.1% percent (SMUD), with the decrease sustained over time (seven months (PSE) and twelve months (SMUD)).

Coordination exercise and postural stability in elderly people: effect of Tai Chi Chuan

Objective: To evaluate the effects of coordination exercise on postural stability in older individuals by Chinese shadow boxing, Tai Chi Chuan (TCC). Design: Cross-sectional study. Setting: Research project in a hospital-based biomechanical laboratory. Participants: The TCC group (n ϭ 25) had been practicing TCC regularly for 2 to 35 years. The control group (n ϭ 14) included healthy and active older subjects. Intervention Results: In static postural control, the results showed no differences between the TCC or control group in the more simple conditions, but in the more complicated SOT (eyes closed with sway surface, sway vision with sway surface), the TCC group had significantly better results than the control group. The TCC group also had significantly better results in the rhythmic forward-backward weight-shifting test. Duration of practice did not seem to affect the stability of elder people. Conclusion: The elderly people who regularly practiced TCC showed better postural stability in the more challenged conditions than those who do not (eg, the condition with simultaneous disturbance of vision and proprioception). TCC as a coordination exercise may reduce the risk of a fall through maintaining the ability of posture control. Key Words: Balance; Elderly; Exercise; Posture; Rehabilitation; T'ai Chi. © by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation P REVENTIVE CARE for the elderly has received increased attention because of the rapid increase in the elderly population and their disproportionately high medical expenses. 1 Falls are a major cause of morbidity, hospitalization, and mortality among older people. 2-4 Approximately 30% of those over 65 years of age sustain a fall, with about half of them having multiple events. About 10% to 15% of falls result in serious injuries and in soft tissue injuries. Many studies show that impaired balance and decreased lower extremity strength are important risk factors in the loss of physical functioning and the occurrence of falls in older adults. Tai Chi Chuan (TCC) is a traditional Chinese conditioning exercis

Encapsulated membrane proteins: a simplified system for molecular simulation

Over the past 50 years there has been considerable progress in our understanding of biomolecular interactions at an atomic level. This in turn has allowed molecular simulation methods employing full atomistic modeling at ever larger scales to develop. However, some challenging areas still remain where there is either a lack of atomic resolution structures or where the simulation system is inherently complex. An area where both challenges are present is that of membranes containing membrane proteins. In this review we analyse a new practical approach to membrane protein study that offers a potential new route to high resolution structures and the possibility to simplify simulations. These new approaches collectively recognise that preservation of the interaction between the membrane protein and the lipid bilayer is often essential to maintain structure and function. The new methods preserve these interactions by producing nano-scale disc shaped particles that include bilayer and the chosen protein. Currently two approaches lead in this area: the MSP system that relies on peptides to stabilise the discs, and SMALPs where an amphipathic styrene maleic acid copolymer is used. Both methods greatly enable protein production and hence have the potential to accelerate atomic resolution structure determination as well as providing a simplified format for simulations of membrane protein dynamics

Magnetic-field-dependent zero-bias diffusive anomaly in Pb oxide-n-InAs structures: Coexistence of two- and three-dimensional states

The results of experimental and theoretical studies of zero-bias anomaly (ZBA) in the Pb-oxide-n-InAs tunnel structures in magnetic field up to 6T are presented. A specific feature of the structures is a coexistence of the 2D and 3D states at the Fermi energy near the semiconductor surface. The dependence of the measured ZBA amplitude on the strength and orientation of the applied magnetic field is in agreement with the proposed theoretical model. According to this model, electrons tunnel into 2D states, and move diffusively in the 2D layer, whereas the main contribution to the screening comes from 3D electrons.Comment: 8 double-column pages, REVTeX, 9 eps figures embedded with epsf, published versio

Nature can cool cities, but proceed with caution

Increased extreme heat events draw attention to the potential of urban nature as a heat adaptation strategy for cities. This is reflected in multiple scientific perspective pieces, policy documents and science media publications advocating for urban greening as a cooling approach. Although attention to the dangers of heat and the benefits of urban nature is welcomed, it is vital that nature-based approaches to cooling are underpinned by diverse knowledge and a sound understanding of what nature in cities can and cannot do. We explain why an evidence-driven and cautious approach to heat adaptation through urban greening is so important, and propose three actions that urban actors can take towards effective and equitable long-term cooling through urban nature: enabling dialogue between different sectors with multiple remits; including diverse knowledge systems in planning and governance processes; and investing in long-term stewardship for the climatological and societal conditions of the coming decades. Policy and practice recommendation • Create fora for dialogue between governments, residents, civil society and developers from planning stage for green cooling; • Cooling through nature must be driven by expertise spanning diverse knowledge systems, combined with local knowledge and community needs; • Consider future climates and stewardship when planning urban cooling via nature. Science highlights • Understanding link between urban thermal environment and nature is an inter- and transdisciplinary task; • Critical need for evidence of how greening reduces heat impacts across different social and cultural contexts; • Evidence of how species perform under future climates required for stewardship of urban nature

Drug Delivery through the Blood-Brain Barrier through Use of Vascular Cell Adhesion Molecule 1- Targeted Nanoparticles

The blood brain barrier (BBB) is a semi-permeable membrane separating the brain from the bloodstream, preventing many drugs that treat neurological diseases, such as Alzheimer’s and Parkinson’s, from reaching the brain. Our project aimed to create a novel drug delivery system targeting the brain during neural inflammation. We developed a cationic solid lipid nanoparticle (CSLN) complex composed of cationic nanoparticles, biotin, streptavidin, and anti-vascular cell adhesion molecule-1 (anti- VCAM-1) antibodies. The anti-VCAM-1 antibody is used to target VCAM-1, a cell adhesion protein found on the BBB endothelium. VCAM-1 expression is elevated in the presence of inflammatory molecules, such as tumor necrosis factor-alpha (TNF- α). Through the use of a simple BBB model, results showed that our novel drug delivery system experienced some level of success in targeting the brain inflammation due to increasing TNF-α concentrations. This is promising for drug delivery research and provides support for VCAM-1 targeting using more robust and complex BBB models

A dynamic T cell–limited checkpoint regulates affinity-dependent B cell entry into the germinal center

Entry into the germinal center requires antigen-bearing B cells to compete for cognate T cell help at the T–B border

Peroxisome Proliferator–Activated Receptor γ Level Contributes to Structural Integrity and Component Production of Elastic Fibers in the AortaNovelty and Significance

Loss of integrity and massive disruption of elastic fibers are key features of abdominal aortic aneurysm (AAA). Peroxisome proliferator-activated receptor γ (PPARγ) has been shown to attenuate AAA through inhibition of inflammation and proteolytic degradation. However, its involvement in elastogenesis during AAA remains unclear. PPARγ was highly expressed in human AAA within all vascular cells, including inflammatory cells and fibroblasts. In the aortas of transgenic mice expressing PPARγ at 25% normal levels (PpargC/− mice), we observed the fragmentation of elastic fibers and reduced expression of vital elastic fiber components of elastin and fibulin-5. These were not observed in mice with 50% normal PPARγ expression (Pparg+/− mice). Infusion of a moderate dose of angiotensin II (AngII) (500 ng/kg/min) did not induce AAA but Pparg+/− aorta developed flattened elastic lamellae, while PpargC/− aorta showed severe destruction of elastic fibers. After infusion of AngII at 1000 ng/kg/min, 73% of PpargC/− mice developed atypical suprarenal aortic aneurysms: superior mesenteric arteries were dilated with extensive collagen deposition in adventitia and infiltrations of inflammatory cells. Although matrix metalloproteinase inhibition by doxycycline somewhat attenuated the dilation of aneurysm, it did not reduce the incidence nor elastic lamella deterioration in AngII-infused PpargC/− mice. Furthermore, PPARγ antagonism down-regulated elastin and fibulin-5 in fibroblasts, but not in vascular smooth muscle cells. Chromatin immunoprecipitation assay demonstrated PPARγ binding in the genomic sequence of fibulin-5 in fibroblasts. Our results underscore the importance of PPARγ in AAA development though orchestrating proper elastogenesis and preserving elastic fiber integrity

NOTUM promotes thermogenic capacity and protects against diet-induced obesity in male mice.

We recently showed that NOTUM, a liver-secreted Wnt inhibitor, can acutely promote browning of white adipose. We now report studies of chronic overexpression of NOTUM in liver indicating that it protects against diet-induced obesity and improves glucose homeostasis in mice. Adeno-associated virus (AAV) vectors were used to overexpress GFP or mouse Notum in the livers of male C57BL/6J mice and the mice were fed an obesifying diet. After 14 weeks of high fat, high sucrose diet feeding, the AAV-Notum mice exhibited decreased obesity and improved glucose tolerance compared to the AAV-GFP mice. Gene expression and immunoblotting analysis of the inguinal fat and brown fat revealed increased expression of beige/brown adipocyte markers in the AAV-Notum group, suggesting enhanced thermogenic capacity by NOTUM. A β3 adrenergic receptor agonist-stimulated lipolysis test suggested increased lipolysis capacity by NOTUM. The levels of collagen and C-C motif chemokine ligand 2 (CCL2) in the epididymal white adipose tissue of the AAV-Notum mice were significantly reduced, suggesting decreased fibrosis and inflammation, respectively. RNA sequencing analysis of inguinal white adipose of 4-week chow diet-fed mice revealed a highly significant enrichment of extracellular matrix (ECM) functional cluster among the down-regulated genes in the AAV-Notum group, suggesting a potential mechanism contributing to improved glucose homeostasis. Our in vitro studies demonstrated that recombinant human NOTUM protein blocked the inhibitory effects of WNT3A on brown adipocyte differentiation. Furthermore, NOTUM attenuated WNT3A's effects on upregulation of TGF-β signaling and its downstream targets. Overall, our data suggest that NOTUM modulates adipose tissue function by promoting thermogenic capacity and inhibiting fibrosis through inhibition of Wnt signaling