Here we report that attempted preparation of low-valent Ca
complexes in the form of LCa-CaL (where L is a bulky β-diketiminate ligand) under dinitrogen (N
) atmosphere led to isolation of LCa(N
)CaL, ...which was characterized crystallographically. The N
- anion in this complex reacted in most cases as a very potent two-electron donor. Therefore, LCa(N
)CaL acts as a synthon for the low-valent Ca
complex LCa-CaL, which was the target of our studies. The N
- anion could also be protonated to diazene (N
H
) that disproportionated to hydrazine and N
The role of Ca d orbitals for N
activation is discussed.
The purpose of this special issue is to elucidate concepts of value and methods of valuation that will assist in guiding human decisions vis-à-vis ecosystems. The concept of ecosystem service value ...can be a useful guide when distinguishing and measuring where trade-offs between society and the rest of nature are possible and where they can be made to enhance human welfare in a sustainable manner. While win-win opportunities for human activities within the environment may exist, they also appear to be increasingly scarce in a ‘full’ global ecological–economic system. This makes valuation all the more essential for guiding future human activity. This paper provides some history, background, and context for many of the issues addressed by the remaining papers in this special issue. Its purpose is to place both economic and ecological meanings of value, and their respective valuation methods, in a comparative context, highlighting strengths, weakness and addressing questions that arise from their integration.
Achilles tendon ruptures have been linked with detrimental changes in muscle-tendon structure, which may help explain long-term functional deficits. However, the causal effects of muscle-tendon ...structure on joint function have not been tested in a controlled setting. Therefore, the purpose of this study was to test the implications of muscle-tendon unit parameters on simulated single-leg heel raise height. We hypothesized that muscle fiber length and resting ankle angle – a clinical surrogate measure of tendon slack length – would predict single-leg heel raise height more strongly than other parameters. To test this hypothesis, we developed a two-part simulation paradigm that recreated clinically relevant muscle-tendon scenarios and then tested these parameters on single-leg heel raise height. We found that longer muscle fibers had the greatest positive effect on single-leg heel raise height. However, tendon slack length, determined by simulating resting ankle angles in a secondary analysis, revealed a stronger negative correlation with heel raise height. Our findings support previous clinical observations that both muscle fascicle length and resting tendon length are important muscle-tendon parameters for patient function. In addition to minimizing tendon elongation following rupture, treatment plans should focus on preserving plantarflexor muscle structure to mitigate functional loses following Achilles tendon ruptures.
Imprinting of the Prader-Willi/Angelman syndrome region on human chromosome 15 is regu1Ated by an imprinting centre (IC), which spans 5′ exons of the gene encoding the small nuclear ribonucleoprotein ...N (SNRPN). The IC/SNRPNtranscripts are initiated at two alternative start sites, which share a high degree of sequence similarity with each other and with two newly identified sites 63 and >700 kb further upstream. Three of these sites are hypermethylated on the maternal chromosome, whereas one displays an opposite methylation pattern. We have also identified novel splice variants of the IC/SNRPN transcripts and hitherto undetected exons. One of these exons, which we designate u5, is deleted in all Angelman syndrome patients with a microdeletion of the IC. We conclude that elements of the IC region have undergone multiple duplication events and that u5 or a sequence close by may play a role in maternal imprinting.
Follicular lymphoma (FL) is the most common indolent non-Hodgkin lymphoma, with median age at diagnosis in the seventh decade. FL in young adults (YAs), defined as diagnosis at ≤40 years, is ...uncommon. No standard approaches exist guiding the treatment of YA FL, and little is known about their disease characteristics and outcomes. To gain further insights into YA FL, we analyzed the National LymphoCare Study (NLCS) to describe characteristics, initial treatments, and outcomes in this population versus patients aged >40 years.
Using the NLCS database, we stratified FL patients by age: 18–40 (YA), 41–60, 61–70, 71–80, and >80 years. Survival probability was estimated using Kaplan–Meier methodology. We examined associations between age and survival using hazard ratios and 95% confidence intervals (CIs) from multivariable Cox models.
Of 2652 eligible FL patients in the NLCS, 164 (6%) were YAs. Of YA patients, 69% had advanced disease, 80% had low-grade histology, and 50% had good-risk disease according to the Follicular Lymphoma International Prognostic Index (FLIPI). Nineteen percent underwent observation, 12% received rituximab monotherapy, and 46% received chemoimmunotherapy in 59% of these: R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone). With a median follow-up of 8 years, overall survival (OS) at 2, 5, and 8 years was 98% (95% CI 93–99), 94% (95% CI 89–97), and 90% (95% CI 83–94), respectively. Median progression-free survival (PFS) was 7.3 years (95% CI 5.6–not reached).
In one of the largest cohorts of YA FL patients treated in the rituximab era, disease characteristics and outcomes were similar to patients aged 41–60 years, with favorable OS and PFS in YAs. Longer-term outcomes and YA-specific survivorship concerns should be considered when defining management. These data may not support the need for more aggressive therapies in YA FL.
Roche/Genentech ML01377 (U2963n).
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