Publications

A diblock copolymer containing a fullerene(C60)-rich block and a poly(3-hexylthiophene) block functions as a compatibilizer in poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester (P3HT:PCBM) blends. The copolymer is used to probe the impact of morphology and phase-segregation kinetics on the performance of P3HT:PCBM-based solar cells. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2089/2006/c1787_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Weaving organic threads Woven fabrics are inherently flexible. Liu et al. created a molecular fabric analog using metal-organic frameworks (see the Perspective by Gutierrez-Puebla). Phenanthroline ligands on a copper metal complex directed the addition of organic linkers via imine bonds to create helical organic threads with woven texture. Removing the copper allowed the strands to slide against each other and increased the elasticity of the material 10-fold. Science , this issue p. 365 ; see also p. 336

A thick sequence of Late Miocene to Pleistocene sediments thought to represent deposition in a Neogene forearc basin are preserved in the structural basin referred to as the Eel River basin' located offshore of NW California and SE Oregon. The southern portion of this structural basin comes on land in the vicinity of Eureka where the marine and fluvial Wildcat Group is exposed. Basal Wildcat Group sediments are fluvial and littorial. Marine sandstones of the Wildcat Group contain K-spar concentrations of 5.5% and are believed to represent a fresh source. [sup 40]Ar/[sup 39]Ar laser probe analyses of Wildcat Group micas yield dates of 52--57, 66--75, 128.5 and 299--303 Ma. The presence of Idaho detritus throughout the Neogene Wildcat Group indicates that the Klamath Mountains remained low during the Pliocene and early Pleistocene. Younger fluvial sediments in this region contain primarily locally derived detritus indicating local uplift of the Klamath Mountains. To the north, at Crescent City, thin remnants of the near-shore Saint George Formation and the eastern estuarine and fluvial Wimer Formation are lowermost Pliocene in age (5 ma). The presence of the highly erodible Wilmer Formation on uplifted plateaus in an area of extreme rainfall suggest that these sedimentsmore » represent only the lowermost portion of an originally much thicker sequence. Consequently, the sediments confined to the present day Eel River basin do not represent the lateral extent of the original forearc basin. Sandstones and conglomerates of the Saint George and Wimer Formation indicate a local Klamath provenance derivation.« less

Following the long-held belief that the Internet is hierarchical, the network topology generators most widely used by the Internet research community, Transit-Stub and Tiers, create networks with a deliberately hierarchical structure. However, in 1999 a seminal paper by Faloutsos et al. revealed that the Internet's degree distribution is a power-law. Because the degree distributions produced by the Transit-Stub and Tiers generators are not power-laws, the research community has largely dismissed them as inadequate and proposed new network generators that attempt to generate graphs with power-law degree distributions.Contrary to much of the current literature on network topology generators, this paper starts with the assumption that it is more important for network generators to accurately model the large-scale structure of the Internet (such as its hierarchical structure) than to faithfully imitate its local properties (such as the degree distribution). The purpose of this paper is to determine, using various topology metrics, which network generators better represent this large-scale structure. We find, much to our surprise, that network generators based on the degree distribution more accurately capture the large-scale structure of measured topologies. We then seek an explanation for this result by examining the nature of hierarchy in the Internet more closely; we find that degree-based generators produce a form of hierarchy that closely resembles the loosely hierarchical nature of the Internet.

Background Reverse cholesterol transport from peripheral tissues is considered the principal atheroprotective mechanism of high‐density lipoprotein, but quantifying reverse cholesterol transport in humans in vivo remains a challenge. We describe here a method for measuring flux of cholesterol though 3 primary components of the reverse cholesterol transport pathway in vivo in humans: tissue free cholesterol ( FC ) efflux, esterification of FC in plasma, and fecal sterol excretion of plasma‐derived FC . Methods and Results A constant infusion of [2,3‐ 13 C 2 ]‐cholesterol was administered to healthy volunteers. Three‐compartment SAAM II (Simulation, Analysis, and Modeling software; SAAM Institute, University of Washington, WA) fits were applied to plasma FC , red blood cell FC , and plasma cholesterol ester 13 C–enrichment profiles. Fecal sterol excretion of plasma‐derived FC was quantified from fractional recovery of intravenous [2,3‐ 13 C 2 ]‐cholesterol in feces over 7 days. We examined the key assumptions of the method and evaluated the optimal clinical protocol and approach to data analysis and modeling. A total of 17 subjects from 2 study sites (n=12 from first site, age 21 to 75 years, 2 women; n=5 from second site, age 18 to 70 years, 2 women) were studied. Tissue FC efflux was 3.79±0.88 mg/kg per hour (mean ± standard deviation), or ≈8 g/d. Red blood cell–derived flux into plasma FC was 3.38±1.10 mg/kg per hour. Esterification of plasma FC was ≈28% of tissue FC efflux (1.10±0.38 mg/kg per hour). Recoveries were 7% and 12% of administered [2,3‐ 13 C 2 ]‐cholesterol in fecal bile acids and neutral sterols, respectively. Conclusions Three components of systemic reverse cholesterol transport can be quantified, allowing dissection of this important function of high‐density lipoprotein in vivo. Effects of lipoproteins, genetic mutations, lifestyle changes, and drugs on these components can be assessed in humans.

There appears to be a sex difference for some clinical features, particularly hopelessness, among depressed suicidal children and adolescents. Whether hopelessness is a sex-specific characteristic of depressed suicidal children and adolescents requires further study.

The discovery of Li-excess cation-disordered rocksalt (DRX) cathodes greatly enlarges the design space beyond the layered NCM-type rocksalt chemistries. More importantly, this new strategy enables high capacity Co and Ni-free cathodes, which is a requirement for the Li-ion industry to grow to the Terra-Wh scale that is needed for the growing electric vehicle and utility applications. Mn-based DRX oxyfluorides are especially promising owing to their large energy densities and good cyclabilities as well as the low cost and earth abundance of Mn. Herein, we synthesize, characterize, electrochemically test and model four well-chosen compositions within the Li–Mn–O–F DRX chemical space with different Li content and F content: Li 1.333 Mn(III) 0.667 O 1.333 F 0.667 (HLF67), Li 1.333 Mn(III) 0.5 Mn(IV) 0.167 O 1.5 F 0.5 (HLF50), Li 1.333 Mn(III) 0.333 Mn(IV) 0.333 O 1.667 F 0.333 (HLF33), and Li 1.25 Mn(II) 0.167 Mn(III) 0.583 O 1.333 F 0.667 (LLF67). While all compositions tested achieve higher than 200 mAh/g initial capacity the material with high Li-excess (1.333 per formula unit, Li x Mn 2- x O 2- y F y ) and moderate fluorination (0.333 per formula unit) achieves 349 mAh/g initial capacity and 1068 Wh/kg specific energy. Higher fluorination (0.667 per formula unit) can activate Mn 2+ /Mn 4+ redox and thereby balance capacity with cycle life, achieving 256 mAh/g (822 Wh/kg) initial capacity (specific energy) with more than 85% retained after 30 cycles even upon charging to 5.0V. It can be concluded that the Li-site distribution plays a more important role than the metal-redox capacity in determining the initial capacity, whereas the metal-redox capacity is more closely related to the cyclability of the materials. We apply these insights and generate a capacity map of the Li–Mn–O–F chemical space, Li x Mn 2- x O 2- y F y (1.167 ≤ x ≤ 1.333, 0 ≤ y ≤ 0.667), which predicts both the accessible Li capacity and Mn-redox capacity. This map allows to design compounds which balance high capacity with good cyclability. Reference Lun, Zhengyan, et al. "Design principles for high-capacity Mn-based cation-disordered rocksalt cathodes.” Chem (2019), DOI: 10.1016/j.chempr.2019.10.001, in press.

Inverse design is a powerful tool in wave-physics and in particular in photonics for compact, high-performance devices. To date, applications have mostly been limited to linear systems and it has rarely been investigated or demonstrated in the nonlinear regime. In addition, the "black box" nature of inverse design techniques has hindered the understanding of optimized inverse-designed structures. We propose an inverse design method with interpretable results to enhance the efficiency of on-chip photon generation rate through nonlinear processes by controlling the effective phase-matching conditions. We fabricate and characterize a compact, inverse-designed device using a silicon-on-insulator platform that allows a spontaneous four-wave mixing process to generate photon pairs at 1.1MHz with a coincidence to accidental ratio of 162. Our design method accounts for fabrication constraints and can be used for scalable quantum light sources in large-scale communication and computing applications.

Key Points NKG2D, but not NKp46, has a modest, NK cell intrinsic influence on shaping the NK cell receptor repertoire. NKG2D deficiency does not alter the NK cell response to MCMV infection.