Alkaline hydrogen peroxide treatment unlocks energy in agricultural by-products

Lignocellulosic residues (wheat straw, corncobs, and cornstalks) were treated with a dilute alkaline solution of hydrogen peroxide and suspended in cattle rumen in situ to measure microbial degradation. The rate and extent of dry matter disappearance were markedly increased as a result of the treatment. Results in vivo indicate that this treatment increases the fermentability of wheat straw structural carbohydrates such that this agricultural by-product may be considered an acceptable energy source for the ruminant animal. Treatment of wheat straw allowed more complete bacterial colonization and more rapid degradation of the cell wall.     

Glacial-holocene transition in deep-sea carbonates: selective dissolution and the stable isotope signal

The oxygen and carbon isotopic signals of planktonic Foraminifera from closely spaced samples from two box cores taken in the western equatorial Pacific change through the glacial-to-Holocene transition as a result of several factors, one of which is the Holocene dissolution pulse starting about 12,000 years ago and reaching full force shortly after. The onset of dissolution comes shortly after the maximum rate of deglaciation but well before the maximum drop in fertility in upper waters. The effect of dissolution is 20 to 30 percent of the amplitude of isotopic change in Globigerinoides sacculifer, at the depth of the present lysocline.     

Norepinephrine: reversal of anorexia in rats with lateral hypothalamic damage

Injection of norepinephrine in the lateral ventricles of rats recovering from lateral hypothalamic anorexia caused immediate feeding and, frequently, overeating. Intraventricular administration of the alpha-noradrenergic blocker, phentolamine, suppressed feeding in both normal rats and rats that had recovered from lateral hypothalamic lesions. Feeding is reinforced by ascending medial forebrain bundle fibers that form alpha-noradrenergic synapses in the hypothalamus and forebrain. Damage to these fibers suppresses feeding by reducing noradrenergic transmission and, hence, the rewarding value of food. Recovery of feeding after hypothalamic lesions coincides with the recovery of noradrenergic reward function.     

Benzodiazepines: anxiety-reducing activity by reduction of serotonin turnover in the brain

The anxiety-reducing effects of minor tranquilizers in the rat conflict test were mimicked by serotonin antagonists and by p-chlorophenylalanine, an inhibitor of serotonin synthesis; the depressant effects of the minor tranquilizers were mimicked by norepinephrine antagonists. Intraventricular injections of serotonin led to a suppression of behavior, and also antagonized the anxiety-reducing action of benzodiazeprines. Intraventricular injections of norepinephrine led to a release of punished behavior from suppression, and also antagonized the depressant action of benzodiazepines. The anxiety-reducing activity, and the decrease in serotonin turnover induced by benzodiazepines, were maintained over repeated doses, whereas depressant activity, and the decrease induced in norepinephrine turnover, both rapidly underwent tolerance. Tranquilizers may exert their anxiety-reducing effects by a reduction of serotonin activity in a behaviorally suppressive punishment system, and they may exert their depressant effects by a reduction of norepinephrine activity in a behaviorally facilitatory reward system.     

Imaging the surface of Altair

Spatially resolving the surfaces of nearby stars promises to advance our knowledge of stellar physics. Using optical long-baseline interferometry, we constructed a near-infrared image of the rapidly rotating hot star Altair with a resolution of <1 milliarcsecond. The image clearly reveals the strong effect of gravity darkening on the highly distorted stellar photosphere. Standard models for a uniformly rotating star cannot explain our findings, which appear to result from differential rotation, alternative gravity-darkening laws, or both.     

The Hedgehog pathway promotes blood-brain barrier integrity and CNS immune quiescence

The blood-brain barrier (BBB) is composed of tightly bound endothelial cells (ECs) and perivascular astrocytes that regulate central nervous system (CNS) homeostasis. We showed that astrocytes secrete Sonic hedgehog and that BBB ECs express Hedgehog (Hh) receptors, which together promote BBB formation and integrity during embryonic development and adulthood. Using pharmacological inhibition and genetic inactivation of the Hh signaling pathway in ECs, we also demonstrated a critical role of the Hh pathway in promoting the immune quiescence of BBB ECs by decreasing the expression of proinflammatory mediators and the adhesion and migration of leukocytes, in vivo and in vitro. Overall, the Hh pathway provides a barrier-promoting effect and an endogenous anti-inflammatory balance to CNS-directed immune attacks, as occurs in multiple sclerosis.     

The foot and ankle of Australopithecus sediba

A well-preserved and articulated partial foot and ankle of Australopithecus sediba, including an associated complete adult distal tibia, talus, and calcaneus, have been discovered at the Malapa site, South Africa, and reported in direct association with the female paratype Malapa Hominin 2. These fossils reveal a mosaic of primitive and derived features that are distinct from those seen in other hominins. The ankle (talocrural) joint is mostly humanlike in form and inferred function, and there is some evidence for a humanlike arch and Achilles tendon. However, Au. sediba is apelike in possessing a more gracile calcaneal body and a more robust medial malleolus than expected. These observations suggest, if present models of foot function are correct, that Au. sediba may have practiced a unique form of bipedalism and some degree of arboreality. Given the combination of features in the Au. sediba foot, as well as comparisons between Au. sediba and older hominins, homoplasy is implied in the acquisition of bipedal adaptations in the hominin foot.