Enabling Simultaneous Extreme Ultra Low-k in Stiff, Resilient, and Thermally Stable Nano-Architected Materials

Low dielectric constant (low-k) materials have gained increasing popularity because of their critical role in developing faster, smaller, and higher performance devices. Their practical use has been limited by the strong coupling among mechanical, thermal, and electrical properties of materials and their dielectric constant; a low-k is usually attained by materials that are very porous, which results in high compliance, that is, silica aerogels; high dielectric loss, that is, porous polycrystalline alumina; and poor thermal stability, that is, Sr-based metal–organic frameworks. We report the fabrication of 3D nanoarchitected hollow-beam alumina dielectrics which k is 1.06–1.10 at 1 MHz that is stable over the voltage range of −20 to 20 V and a frequency range of 100 kHz to 10 MHz. This dielectric material can be used in capacitors and is mechanically resilient, with a Young’s modulus of 30 MPa, a yield strength of 1.07 MPa, a nearly full shape recoverability to its original size after >50% compressions, and outstanding thermal stability with a thermal coefficient of dielectric constant (TCK) of 2.43 × 10^(-5) K^(-1) up to 800 °C. These results suggest that nanoarchitected materials may serve as viable candidates for ultra low-k materials that are simultaneously mechanically resilient and thermally and electrically stable for microelectronics and devices

Reviews

The following publications have been reviewed by the mentioned authors;Beginning Graphical Communication by M. Jordan, B. Hawtin and A. Neil, reviewed by John LeesArt Related Topics by Bob Nunn and Chris Locke, reviewed by A. CharltonHandbook for Art and Design Students by Robin Jesson, reviewed by John LancasterDrawing and Cognition Descriptive and Experimental Studies of Graphic Production Processes by Peter Van Sommers, reviewed by Pamela M. SchenkThe Student's Guide to Western Calligraphy an Illustrated Survey by Joyce Irene Whalley, reviewed by John LancasterSource Directory for Authentic Indian, Eskimo and Aleut Arts and Crafts by the Indian Arts and Crafts BoardMarianne Straub by Mary Schoeser, reviewed by Kim GreerMisha Black by Avril Blake, reviewed by Kim Greer'Working in Crafts' - A National Survey by the Crafts Council, reviewed by L. SayerDirectory of Design Expertise by the Design Council, reviewed by R. Smit

Enabling Simultaneous Extreme Ultra Low-k in Stiff, Resilient, and Thermally Stable Nano-Architected Materials

Low dielectric constant (low-k) materials have gained increasing popularity because of their critical role in developing faster, smaller, and higher performance devices. Their practical use has been limited by the strong coupling among mechanical, thermal, and electrical properties of materials and their dielectric constant; a low-k is usually attained by materials that are very porous, which results in high compliance, that is, silica aerogels; high dielectric loss, that is, porous polycrystalline alumina; and poor thermal stability, that is, Sr-based metal–organic frameworks. We report the fabrication of 3D nanoarchitected hollow-beam alumina dielectrics which k is 1.06–1.10 at 1 MHz that is stable over the voltage range of −20 to 20 V and a frequency range of 100 kHz to 10 MHz. This dielectric material can be used in capacitors and is mechanically resilient, with a Young’s modulus of 30 MPa, a yield strength of 1.07 MPa, a nearly full shape recoverability to its original size after >50% compressions, and outstanding thermal stability with a thermal coefficient of dielectric constant (TCK) of 2.43 × 10^(-5) K^(-1) up to 800 °C. These results suggest that nanoarchitected materials may serve as viable candidates for ultra low-k materials that are simultaneously mechanically resilient and thermally and electrically stable for microelectronics and devices

Factors affecting the recovery of Mexican wolves in the Southwest United States

Recovering and maintaining large carnivore populations is a global conservation challenge that requires better knowledge of the factors affecting their populations, particularly in shared landscapes (i.e. non-protected areas where people occupy and or utilize the land). The Mexican wolf (Canis lupus baileyi) is an endangered wolf subspecies being recovered on shared landscapes in the Southwest United States and Mexico. We used data from the U.S. program to model population growth, evaluate the impact of management removal and illegal killing relative to other demographic factors, and test hypotheses about factors influencing rates of management removal and illegal killing. From 1998 to 2019, the population growth averaged 12% per year. Rates of natural reproduction, illegal killing and other mortality remained consistent over the 22 years; while releases, translocations and management removals varied markedly between two time periods, phase 1:1998–2007 and phase 2:2008–2019. The number of wolves removed for conflict management was higher during phase 1 (average ~ 13 per year, rate = 24.8%) than phase 2 (average of ~5 per year, rate = 5.2%). This decrease in management removal resulted in the wolf population resuming growth after a period of population stagnation. Two factors influenced this decrease, a change in policy regarding removal of wolves (stronger modelling support) and a decrease in the number of captive-reared adult wolves released into the wild (weaker modelling support). Illegal mortality was relatively constant across both phases, but after the decrease in management removal, illegal mortality became the most important factor (relative importance shifted from 28.2% to 50.1%). Illegal mortality was positively correlated with rates of reintroduction and translocation of wolves and negatively correlated with the rate of management removal. 6. Synthesis and applications. Using management removal to reduce human–carnivore conflict can have negative population impacts if not used judiciously. Recovering and maintaining carnivore populations in shared landscapes may require greater tolerance of conflict and more emphasis on effective conflict prevention strategies and compensation programs for affected stakeholders

Recoverable electrical breakdown strength and dielectric constant in ultra-low k nanolattice capacitors

The dielectric reliability of low-k materials during mechanical deformation attracts tremendous attention, owing to the increasing demand for thin electronics to meet the ever-shrinking form factor of consumer products. However, the strong coupling between dielectric/electric and mechanical properties limits the use of low-k dielectrics in industrial applications. We report the leakage current and dielectric properties of a nanolattice capacitor during compressive stress cycling. Electrical breakdown measurements during the stress cycling, combined with a theoretical model and in situ mechanical experiments, provide insights to key breakdown mechanisms. Electrical breakdown occurs at nearly 50% strain, featuring a switch-like binary character, correlated with a transition from beam bending and buckling to collapse. Breakdown strength appears to recover after each cycle, concomitant with nanolattice’s shape recovery. The compressive displacement at breakdown decreases with cycling due to permanently buckled beams, transforming the conduction mechanism from Schottky to Poole–Frankel emission. Remarkably, our capacitor with 99% porosity, k ∼ 1.09, is operative up to 200 V, whereas devices with 17% porous alumina films breakdown upon biasing based on a percolation model. Similarly with electrical breakdown, the dielectric constant of the capacitor is recoverable with five strain cycles and is stable under 25% compression. These outstanding capabilities of the nanolattice are essential for revolutionizing future flexible electronics

The first clinical implementation of a real-time six degree of freedom target tracking system during radiation therapy based on Kilovoltage Intrafraction Monitoring (KIM).

PURPOSE: We present the first clinical implementation of a real-time six-degree of freedom (6DoF) Kilovoltage Intrafraction Monitoring (KIM) system which tracks the cancer target translational and rotational motions during treatment. The method was applied to measure and correct for target motion during stereotactic body radiotherapy (SBRT) for prostate cancer. METHODS: Patient: A patient with prostate adenocarcinoma undergoing SBRT with 36.25Gy, delivered in 5 fractions was enrolled in the study. 6DoF KIM technology: 2D positions of three implanted gold markers in each of the kV images (125kV, 10mA at 11Hz) were acquired continuously during treatment. The 2D→3D target position estimation was based on a probability distribution function. The 3D→6DoF target rotation was calculated using an iterative closest point algorithm. The accuracy and precision of the KIM method was measured by comparing the real-time results with kV-MV triangulation. RESULTS: Of the five treatment fractions, KIM was utilised successfully in four fractions. The intrafraction prostate motion resulted in three couch shifts in two fractions when the prostate motion exceeded the pre-set action threshold of 2mm for more than 5s. KIM translational accuracy and precision were 0.3±0.6mm, -0.2±0.3mm and 0.2±0.7mm in the Left-Right (LR), Superior-Inferior (SI) and Anterior-Posterior (AP) directions, respectively. The KIM rotational accuracy and precision were 0.8°±2.0°, -0.5°±3.3° and 0.3°±1.6° in the roll, pitch and yaw directions, respectively. CONCLUSION: This treatment represents, to the best of our knowledge, the first time a cancer patient's tumour position and rotation have been monitored in real-time during treatment. The 6 DoF KIM system has sub-millimetre accuracy and precision in all three translational axes, and less than 1° accuracy and 4° precision in all three rotational axes

Effects of a multicomponent wellness intervention on dyslipidemia in an overweight adolescent population

Epidemiologic studies suggest that atherosclerotic processes begin in childhood and are associated with abnormal lipid levels. Behavioral changes are the first line of treatment for dyslipidemia in adolescents but outcome data on the effectiveness of this approach are inconsistent. This study aimed to assess the effect of a 13-week multicomponent wellness intervention program on dyslipidemia in lean and overweight/obese adolescents enrolled at a public high school in Boston, Massachusetts. The intervention was conducted at a university-based youth fitness center where 9 overweight/obese adolescents (body mass index [BMI]≥85th percentile for age and sex) and 9 lean adolescents (BMIsex) participated in weekly nutrition classes and structured cardiovascular, flexibility and strength training 2 times/week for 5 weeks, followed by up to 4 times/week for 8 weeks. Clinical measurements (BMI, percent body fat, blood pressure [BP]) and lipid profile assessment (total cholesterol [TC], high-density lipoprotein cholesterol [HDL-C], triglycerides [TG], and low-density lipoprotein cholesterol [LDL-C]) were performed at baseline and at completion of the intervention. At the completion of the study, the overweight/obese adolescents demonstrated a 15% increase in HDL-C levels (mean, 47 mg/dL vs 54 mg/dL) while there was no improvement in BMI, percent body fat, BP,TG, TC and LDL-C. The participants in the lean group showed no change in their anthropometric and serum parameters. A multicomponent wellness intervention resulted in a significant increase of cardioprotective HDL-C levels which has been associated with coronary health in adulthood. The long-term effects of this intervention on indicators of cardiometabolic health and others like it require further study

CVID enteropathy is characterized by exceeding low mucosal IgA levels and interferon-driven inflammation possibly related to the presence of a pathobiont.

Common variable immunodeficiency (CVID), the most common symptomatic primary antibody deficiency, is accompanied in some patients by a duodenal inflammation and malabsorption syndrome known as CVID enteropathy (E-CVID).The goal of this study was to investigate the immunological abnormalities in CVID patients that lead to enteropathy as well as the contribution of intestinal microbiota to this process.We found that, in contrast to noE-CVID patients (without enteropathy), E-CVID patients have exceedingly low levels of IgA in duodenal tissues. In addition, using transkingdom network analysis of the duodenal microbiome, we identified Acinetobacter baumannii as a candidate pathobiont in E-CVID. Finally, we found that E-CVID patients exhibit a pronounced activation of immune genes and down-regulation of epithelial lipid metabolism genes. We conclude that in the virtual absence of mucosal IgA, pathobionts such as A. baumannii, may induce inflammation that re-directs intestinal molecular pathways from lipid metabolism to immune processes responsible for enteropathy

Interleukin-1β sequesters hypoxia inducible factor 2α to the primary cilium.

BACKGROUND: The primary cilium coordinates signalling in development, health and disease. Previously we have shown that the cilium is essential for the anabolic response to loading and the inflammatory response to interleukin-1β (IL-1β). We have also shown the primary cilium elongates in response to IL-1β exposure. Both anabolic phenotype and inflammatory pathology are proposed to be dependent on hypoxia-inducible factor 2 alpha (HIF-2α). The present study tests the hypothesis that an association exists between the primary cilium and HIFs in inflammatory signalling. RESULTS: Here we show, in articular chondrocytes, that IL-1β-induces primary cilia elongation with alterations to cilia trafficking of arl13b. This elongation is associated with a transient increase in HIF-2α expression and accumulation in the primary cilium. Prolyl hydroxylase inhibition results in primary cilia elongation also associated with accumulation of HIF-2α in the ciliary base and axoneme. This recruitment and the associated cilia elongation is not inhibited by blockade of HIFα transcription activity or rescue of basal HIF-2α expression. Hypomorphic mutation to intraflagellar transport protein IFT88 results in limited ciliogenesis. This is associated with increased HIF-2α expression and inhibited response to prolyl hydroxylase inhibition. CONCLUSIONS: These findings suggest that ciliary sequestration of HIF-2α provides negative regulation of HIF-2α expression and potentially activity. This study indicates, for the first time, that the primary cilium regulates HIF signalling during inflammation