On the Chemical Purity and Oxygen Isotopic Composition of α-Cellulose Extractable from Higher Plants and the Implications for Climate, Metabolic, and Physiological Studies.

The O/O ratio of α-cellulose in land plants has proved of interest for climate, environmental, physiological, and metabolic studies. Reliable application of such a ratio may be compromised by the presence of hemicellulose impurities in the α-cellulose product obtainable with current extraction methods, as the impurities are known to be isotopically different from that of the α-cellulose. We first compared the quality of hydrolysates of "α-cellulose products" obtained with four representative extraction methods (Jayme and Wise; Brendel; Zhou; Loader) and quantified the hemicellulose-derived non-glucose sugars in the α-cellulose products from 40 land grass species using gas chromatography-mass spectrometry (GC/MS).

Leaf transition from heterotrophy to autotrophy is recorded in the intraleaf C, H and O isotope patterns of leaf organic matter.

Rationale: Quantitatively relating C/ C, H/ H and O/ O ratios of plant α-cellulose and H/ H of n-alkanes to environmental conditions and metabolic status should ideally be based on the leaf, the plant organ most sensitive to environmental change. The fact that leaf organic matter is composed of isotopically different heterotrophic and autotrophic components means that it is imperative that one be able to disentangle the relative heterotrophic and autotrophic contributions to leaf organic matter.

Methods: We tackled this issue by two-dimensional sampling of leaf water and α-cellulose, and specific n-alkanes from greenhouse-grown immature and mature and field-grown mature banana leaves, taking advantage of their large areas and thick waxy layers.

Calcium homeostasis during hibernation and in mechanical environments disrupting calcium homeostasis.

To maintain calcium homeostasis during physical inactivity, precise coordination is necessary between different organs of the body. There are a number of factors which alter an organism's calcium balance, such as growth, aging, physical inactivity and acquired or inherited disorders which ultimately lead to bone loss. In non-hibernating mammals, physical inactivity causes bone loss which may not be completely recoverable during the lifespan of an individual despite a resumption of activity.

Is recent Afghanistan survey data suitable for fertility analysis? A regional investigation based on fertility inhibiting determinants.

Afghanistan has been a country blighted by war over the past five decades and limited research is available on its demography. This study seeks to assess the suitability of recent survey data for Afghanistan (the 2010 Afghanistan Mortality Survey (AMS)and the 2015 Afghanistan Demographic and Health Survey (ADHS)) for estimating levels and trends in fertility. As several fertility measures rely on the quality of age data, we first apply demographic tools for the identification of age misreporting, finding evidence that it is severe.