Synthesis of neutral nickel catalysts for ethylene polymerization – the influence of ligand size on catalyst stability

A facile synthesis of nickel salicylaldimine complexes with labile dissociating ligands is described. In addition to producing highly active ethylene polymerization catalysts, important insights into the effect of ligand size on catalyst stability and information on the mechanism of polymerization are provided

Advocating Affordable Housing in New Hampshire: The Amicus Curiae Brief of the American Planning Association in Wayne Britton v. Town of Chester

In June 1990, The American Planning Association, a national Washington, D.C. based non-profit association of 27,000 professional planners, elected and appointed planning officials, and citizens interested in improving urban and rural planning filed this amicus curiae brief with the New Hampshire Supreme Court. The case on appeal is Wayne Britton v. Town of Chester, No. 85-E-342 (N.H. Super. Ct. June 27, 1989), brought by a builder/developer and low-income plaintiffs in need of affordable housing in Chester, New Hampshire

Candidate gene analysis of femoral neck trabecular and cortical volumetric bone mineral density in older men.

In contrast to conventional dual-energy X-ray absorptiometry, quantitative computed tomography separately measures trabecular and cortical volumetric bone mineral density (vBMD). Little is known about the genetic variants associated with trabecular and cortical vBMD in humans, although both may be important for determining bone strength and osteoporotic risk. In the current analysis, we tested the hypothesis that there are genetic variants associated with trabecular and cortical vBMD at the femoral neck by genotyping 4608 tagging and potentially functional single-nucleotide polymorphisms (SNPs) in 383 bone metabolism candidate genes in 822 Caucasian men aged 65 years or older from the Osteoporotic Fractures in Men Study (MrOS). Promising SNP associations then were tested for replication in an additional 1155 men from the same study. We identified SNPs in five genes (IFNAR2, NFATC1, SMAD1, HOXA, and KLF10) that were robustly associated with cortical vBMD and SNPs in nine genes (APC, ATF2, BMP3, BMP7, FGF18, FLT1, TGFB3, THRB, and RUNX1) that were robustly associated with trabecular vBMD. There was no overlap between genes associated with cortical vBMD and trabecular vBMD. These findings identify novel genetic variants for cortical and trabecular vBMD and raise the possibility that some genetic loci may be unique for each bone compartment

Exquisite sensitivity of the ligand field to solvation and donor polarisability in coordinatively saturated lanthanide complexes

Crystallographic, emission and NMR studies of a series of C3-symmetric, nine-coordinate substituted pyridyl triazacyclononane Yb(III) and Eu(III) complexes reveal the impact of local solvation and ligand dipolar polarisability on ligand field strength, leading to dramatic variations in pseudocontact NMR shifts and emission spectral profiles, giving new guidance for responsive NMR and spectral probe design

Essential package of palliative care for women with cervical cancer: Responding to the suffering of a highly vulnerable population

Women with cervical cancer, especially those with advanced disease, appear to experience suffering that is more prevalent, complex, and severe than that caused by other cancers and serious illnesses, and approximately 85% live in low- and middle-income countries where palliative care is rarely accessible. To respond to the highly prevalent and extreme suffering in this vulnerable population, we convened a group of experienced experts in all aspects of care for women with cervical cancer, and from countries of all income levels, to create an essential package of palliative care for cervical cancer (EPPCCC). The EPPCCC consists of a set of interventions, medicines, simple equipment, social supports, and human resources, and is designed to be safe and effective for preventing and relieving all types of suffering associated with cervical cancer. It includes only inexpensive and readily available medicines and equipment, and its use requires only basic training. Thus, the EPPCCC can and should be made accessible everywhere, including for the rural poor. We provide guidance for integrating the EPPCCC into gynecologic and oncologic care at all levels of health care systems, and into primary care, in countries of all income levels

Augmented package of palliative care for women with cervical cancer: Responding to refractory suffering

The essential package of palliative care for cervical cancer (EPPCCC), described elsewhere, is designed to be safe and effective for preventing and relieving most suffering associated with cervical cancer and universally accessible. However, it appears that women with cervical cancer, more frequently than patients with other cancers, experience various types of suffering that are refractory to basic palliative care such as what can be provided with the EPPCCC. In particular, relief of refractory pain, vomiting because of bowel obstruction, bleeding, and psychosocial suffering may require additional expertise, medicines, or equipment. Therefore, we convened a group of experienced experts in all aspects of care for women with cervical cancer, and from countries of all income levels, to create an augmented package of palliative care for cervical cancer with which even suffering refractory to the EPPCCC often can be relieved. The package consists of medicines, radiotherapy, surgical procedures, and psycho-oncologic therapies that require advanced or specialized training. Each item in this package should be made accessible whenever the necessary resources and expertise are available

Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES

Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler signals can mimic radial velocity (RV) changes expected from orbiting exoplanets. Exoplanets can be distinguished from activity-induced false positives by the chromaticity and long-term incoherence of starspot signals, but these qualities are poorly constrained for fully-convective M stars. Coherent photometric starspot signals on M dwarfs may persist for hundreds of rotations, and the wavelength dependence of starspot RV signals may not be consistent between stars due to differences in their magnetic fields and active regions. We obtained precise multi-wavelength RVs of four rapidly-rotating M dwarfs (AD Leo, G 227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone Planet Finder, and the optical Keck/HIRES spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the Las Cumbres Observatory (LCO) network of telescopes. We found that all four stars exhibit large spot-induced Doppler signals at their rotation periods, and investigated the longevity and optical-to-NIR chromaticity for these signals. The phase curves remain coherent much longer than is typical for Sunlike stars. Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV modulation consistent in both phase and amplitude. In general, though, we find that the NIR amplitudes are lower than their optical counterparts. We conclude that starspot modulation for rapidly-rotating M stars frequently remains coherent for hundreds of stellar rotations, and gives rise to Doppler signals that, due to this coherence, may be mistaken for exoplanets.Comment: Accepted for publication in the Astrophysical Journa

Resist materials for 157-nm microlithography: an update

Fluorocarbon polymers and siloxane-based polymers have been identified as promising resist candidates for 157 nm material design because of their relatively high transparency at this wavelength. This paper reports our recent progress toward developing 157 nm resist materials based on the first of these two polymer systems. In addition to the 2-hydroxyhexafluoropropyl group, (alpha) -trifluoromethyl carboxylic acids have been identified as surprisingly transparent acidic functional groups. Polymers based on these groups have been prepared and preliminary imaging studies at 157 nm are described. 2-Trifluoromethyl-bicyclo[2,2,1] heptane-2-carboxylic acid methyl ester derived from methyl 2-(trifluoromethyl)acrylate was also prepared and gas-phase VUV measurements showed substantially improved transparency over norbornane. This appears to be a general characteristic of norbornane-bearing geminal electron-withdrawing substituents on the 2 carbon bridge. Unfortunately, neither the NiII nor PdII catalysts polymerize these transparent norbornene monomers by vinyl addition. However, several new approaches to incorporating these transparent monomers into functional polymers have been investigated. The first involved the synthesis of tricyclononene (TCN) monomers that move the bulky electron withdrawing groups further away from the site of addition. The hydrogenated geminally substituted TCN monomer still has far better transparency at 157 nm than norbornane. The second approach involved copolymerizing the norbornene monomers with carbon monoxide. The third approach involved free-radical polymerization of norbornene monomers with tetrafluoroethylene and/or other electron-deficient comonomers. All these approaches provided new materials with encouraging absorbance at 157 nm. The lithographic performance of some of these polymers is discussed