Soil respiration (SR) is a major component of ecosystems’ carbon cycles and represents the second largest CO2 flux in the terrestrial biosphere. Soil temperature is considered to be the primary abiotic control on SR, whereas soil moisture is the secondary control factor. However, soil moisture can become the dominant control on SR in very wet or dry conditions. Determining the trigger that make...

The Sr/Ca ratio of coccoliths was recently proposed as a potential indicator of past growth rates of coccolithophorids, marine algae, which play key roles in both the global carbonate and carbon cycles. We synthesize calibrations of this proxy through laboratory culture studies and analysis of monospecific coccolith assemblages from surface sediments. Cultures of coccolithophorids Helicosphaera...

Depolarization of skeletal muscle fibers induces sarcoplasmic reticulum (SR) Ca(2+) release and contraction that progressively decline while depolarization is maintained. Voltage-dependent inactivation of SR Ca(2+) release channels and SR Ca(2+) depletion are the two processes proposed to explain the decline of SR Ca(2+) release during long-lasting depolarizations. However, the relative contrib...

In cardiomyocytes, [Ca] within the sarcoplasmic reticulum (SR; [Ca]SR) partially determines the amplitude of cytosolic Ca transient that, in turn, governs myocardial contraction. Therefore, it is critical to understand the molecular mechanisms that regulate [Ca]SR handling. Until recently, the best approach available to directly measure [Ca]SR was to use low-affinity Ca indicators (e.g., Fluo-5...

The purpose of the present study was to investigate the suitability of bioabsorbable drawn selfreinforced polyglycolide (SR-PGA) and poly-L/DL-lactide 70:30 (SR-PLA70) implants in experimental and clinical fixations of cancellous bone osteotomies, arthrodeses and fractures. The study consists of a set of two experimental and two clinical studies, including 109 experimental animals and 87 patien...

The origins of signaling by vertebrate steroids are not fully understood. An important advance was the report that an estrogen-binding steroid receptor [SR] is present in amphioxus, a basal chordate with a similar body plan as vertebrates. To investigate the evolution of estrogen-binding to steroid receptors, we constructed a 3D model of amphioxus SR complexed with estradiol. This 3D model indi...

Contraction in skeletal muscle is initiated when Ca stored in the SR is released into the myoplasm in response to membrane depolarization. Studies of the mechanisms that control SR Ca release are aided by methods that permit estimating the Ca permeability of the SR membrane or, equivalently, the extent of activation of the SR Ca release channels. This quantity is proportional to the rate of Ca ...

An improved and updated version of the statistical LOWESS fit to the marine Sr/Sr record and a revised look-up table (V3:10/99; available from [email protected]) based upon it enables straightforward conversion of Sr/Sr to numerical age, and vice versa, for use in strontium isotope stratigraphy (SIS). The table includes 95% confidence intervals on predictions of numerical age from Sr/Sr. Thi...

BACKGROUND The protective role of high-density lipoprotein (HDL) in the cardiovascular system is related to its role in the reverse transport of cholesterol from the arterial wall to the liver for subsequent excretion via the bile. Scavenger receptor class B type I (SR-BI) binds HDL and mediates selective uptake of cholesterol ester and cellular efflux of cholesterol to HDL. The role of SR-BI i...

Analysis of several well-documented specimens from each of the three volcanic series on Oahu gives the following mean ratios of Sr(87) to Sr(86): the Waianae series, 0.7030 +/- 0.00010 (sigma); the Koolau series, 0.70385+/- 0.00009 (sigma); and the Honolulu series, 0.7029 ++/- 0.00006 ( sigma). The mean ratio of Sr(87) to Sr(86) of the Koolau series specimens is significantly higher than the me...