Nuchal ligament reconstructions in diplodocid sauropods support horizontal neck feeding postures

Historically, sauropods have been largely perceived as having vertical, ‘S’-curved necks which were hypothesised to allow them to feed from the canopy of trees. Within the past two decades, this popular perception has been questioned, resulting in a debate over neck posture. The osteological differences between sauropods with horizontal neck posture (Diplodocus), and less horizontally inclined necks (Brachiosaurus) suggest differing life and feeding styles. One differing vertebral feature between these polarised bauplans is the bifurcated neural spine. Regardless of the spine condition, sauropods with and without bifurcated spines have been reconstructed exhibiting the same neck posture. Corroborating histology and morphology in extant taxa highlights the presence of modified vertebral ligaments associated with bifurcated spines. Using these extant taxa to better understand the biomechanics of bifurcated spines, this study proposes alternative soft tissue reconstructions. Previous depictions had the bifurcation trough entirely open or harbouring pneumatic diverticula or muscles; conversely this study proposes that the apices of the bifurcated spines were the anchoring points for a split nuchal ligament, and that the trough of bifurcation was predominantly filled with interspinal ligaments. Ligaments provide energy-efficient elastic rebound, and a paired ligament in the cervical series would aid in prolonged, lateral movement in a horizontal plane (i.e. feeding).     

Changes in free amino acids and polyamine levels in Satsuma leaves in response to Asian citrus psyllid infestation and water stress

The effects of biotic and abiotic stresses on changes in amino acids and polyamine levels in Satsuma orange （Citrus unshiu; cultivar Owari） leaves were inves- tigated. Asian citrus psyllids Diaphorina citri （Kuwayama） （ACP） infestation was used to induce biotic stress while a water deficit was imposed to induce abiotic stress. Potted trees were infested by placing 50 psyllids on 3 citrus leaves enclosed in nylon mesh bags for 5 d. A parallel set of plants were kept water stressed by maintaining the soil at 20% water holding capacity for 5 d. Levels of total free amino acids were higher in water stressed and ACP infested leaves. Polyamine putrescine increased in infested leaves but not in water stressed leaves. Proline was the most abundant amino acid and its levels significantly increased by both biotic and abiotic stresses. Proline levels in infested leaves were significantly higher than the water stressed leaves. Histidine, methionine, asparagine, arginine, serine, and leucine levels also increased significantly in infested leaves, but in water stressed leaves only leucine, methionine, and threonine increased. Levels of amino acids, such as tyrosine, isoleucine, phenylalanine, glutamic acid, and alanine, declined in infested leaves. Under water stress asparagine, phenylalanine, serine, and histidine also declined compared to controls. This indicates that while proteolysis occurred under both stresses, metabolic conversion of amino acids was different under the two stresses. In ACP infested leaves some amino acids may be used as feeding material and/or converted into secondary metabolites for defense.     

Fatal Liver Damage After Barium Enemas Containing Tannic Acid

Tannic acid contained in the barium enema was found to have been the sole known potential hepatotoxin in four of the five cases of fulminating fatal liver failure that occurred in a 213-bed hospital over a period of 27 months. In the other case halothane anesthesia had also been administered. Autopsies (performed on four of the cases) did not suggest viral hepatitis but showed substantially indentical hepatic changes, not unlike those reported in the past following tannic acid exposure. Proof is not claimed that tannic acid was the cause of these deaths, but further investigation regarding the safety of its administration in barium enemas is advocated.     

Hydrogen peroxide mediates reperfusion injury in the isolated rat heart

In an isolated, normothermic rat heart model (Langendorff, 37 °C), dimethylthiourea (DMTU) infusion only during reperfusion reduced both injury and measurable hydrogen peroxide (H₂O₂) concentrations after global ischemia. Cardiac function was assessed by measurement of ventricular developed pressure (DP). H₂O₂ was assessed using H₂O₂ dependent aminotriazole inactivation of myocardial catalase. Depletion of xanthine oxidase by two methods (tungsten or allopurinol inhibition) also improved recovery of function and H₂O₂ production. The results indicate that XO derived H₂O₂ contributes to myocardial reperfusion injury.     

Growth of Salvinia molesta as affected by water temperature and nutrition II. Effects of phosphorus level

The growth of Salvinia molesta D.S. Mitchell, as affected by phosphorus supply and water temperature, was studied in a greenhouse using controlled water temperature baths at 16, 19 and 22°C. For significant responses to the phosphorus treatments to be obtained it was found necessary to use P-deficient plant propagules (containing <0.01% P on a dry matter basis). For these plants the highest relative growth rate and dry matter production occurred at 22°C when they received 10.01 mg PO₄P l^?1, but this was not significantly different from that of plants receiving 1.01 mg PO₄-P l^?1. Over a period of 21 days for plants receiving 0.02 mg PO₄ l^?1 the biomass increased 4-fold at 19°C and 6-fold at 22°C. In contrast, for plants receiving 10.01 mg PO₄-P l^?1 biomass was increased 20-fold at 19°C and 32-fold at 22°C. At the latter temperature, when receiving 60.01 mg PO₄-P l^?1, plants concentrated up to 1.3% of phosphorus on a dry matter basis, suggesting a possible use as a biological filter and purifier of contaminated waters.