Noise characterization of “effective quiet” areas on a U.S. Navy aircraft carrier

The purpose of this investigation was to characterize noise levels in spaces designated as “effective quiet” areas on a U.S. Navy aircraft carrier. Noise dosimetry samples were collected in 15 designated spaces, representing 15 noise measurements, while at-sea during airwing carrier qualifications. Equivalent sound level (L_eq) measurements were collected during flight operations (L_{eq (flt ops)}), non-flight operations (L_{eq (non-flt ops)}), and over 24-hr periods (L_{eq (24-hr)}). These data were compared to the 70 dBA American Conference of Governmental Industrial Hygienists (ACGIH^®) Threshold Limit Value (TLV^®) for “effective quiet” areas intended for temporary threshold shift recovery when personnel live and work in a potentially noise hazardous environment for periods greater than 24?hr. The monitored areas were selected based on personnel occupancy/use during off-duty time periods. Areas were classified by either (1) leisure areas that included mess (eating areas), gyms, lounges, an internet cafe, and the fantail social area or (2) berthing (sleeping) areas. The L_eq measurements in decibels “A” weighted (dBA) were compared to determine significant differences between L_{eq (flt ops)}, L_{eq (non-flt ops)}, and L_{eq (24-hr)} and were compared between leisure area and berthing area. Measured noise levels according to time period ranged as follows: (1) L_{eq (24-hr)}: 70.8–105.4 dBA; (2) L_{eq (flt ops)}: 70–101.2 dBA; and (3) L_{eq (non-flt ops)}: 39.4–104.6 dBA. All area measurements over the 24-hr period and during flight operations and 46.7% of the areas during the non-flight operation time period exceeded the “effective quiet” 70 dBA ACGIH TLV. Mean L_eqs were 15 dBA higher during flight operations compared to non-flight operations in “effective quiet” areas (p?=?0.001). The L_eqs in leisure areas were significantly higher than berthing areas by approximately 21 dBA during non-flight operation periods (p?=?0.001). Results suggest noise levels in “effective quiet” areas frequented by aircraft carrier personnel during off-duty hours when at-sea may inhibit auditory recovery from occupational noise exposures that occur on-duty.     

Thermal unfolding and refolding of a lytic polysaccharide monooxygenase from Thermoascus aurantiacus

Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes which promote the degradation of recalcitrant polysaccharides like cellulose or chitin. Here, we have investigated the thermostability of an LPMO from Thermoascus aurantiacus (TaLPMO9A). TaLPMO9A was found to retain most of its initial activity after incubating at 100 °C while its apparent melting temperature (T_m) is 69 °C at neutral pH. Interestingly, our studies show that holoTaLPMO9A, apoTaLPMO9A and deglycosylated TaLPMO9A can fold back to their original conformation upon lowering the temperature. In the presence of β-mercaptoethanol the protein does not refold. Activity of TaLPMO9A and refolded TaLPMO9A was studied by an Amplex® Red assay as well as by TaLPMO9A catalysed oxidation of phosphoric acid swollen cellulose (PASC). These studies confirm the functional regain of TaLPMO9A activity upon going through one cycle of unfolding and refolding. The thermal unfolding and refolding of TaLPMO9A was measured spectroscopically. Utilizing the two-state model, detailed thermodynamic parameters were obtained for holoTaLPMO. Furthermore, we have investigated the kinetics of TaLPMO9A unfolding and refolding. Our results have implications in understanding LPMO stability, which is crucial for the efficient application of LPMOs as biocatalysts during biomass degradation.

TaLPMO9A regains its catalytic power after a thermal unfolding and refolding cycle.     

Crossveinless 2 regulates bone morphogenetic protein 9 in human and mouse vascular endothelium

The importance of morphogenetic proteins (BMPs) and their antagonists in vascular development is increasingly being recognized. BMP-4 is essential for angiogenesis and is antagonized by matrix Gla protein (MGP) and crossveinless 2 (CV2), both induced by the activin receptor like-kinase 1 (ALK1) when stimulated by BMP-9. In this study, however, we show that CV2 preferentially binds and inhibits BMP-9 thereby providing strong feedback inhibition for BMP-9/ALK1 signaling rather than for BMP-4/ALK2 signaling. CV2 disrupts complex formation involving ALK2, ALK1, BMP-4, and BMP-9 required for the induction of both BMP antagonists. It also limits VEGF expression, proliferation, and tube formation in ALK1-expressing endothelial cells. In vivo, CV2 deficiency translates into a dysregulation of vascular BMP signaling, resulting in an abnormal endothelium with increased endothelial cellularity and expression of lineage markers for mature endothelial cells. Thus, mutual regulation by BMP-9 and CV2 is essential in regulating the development of the vascular endothelium.     

Acrylamide induced inhibition of hepatic glutathione-S-transferase activity in rats

Rats injected i.p. with acrylamide (50 mg/kg/day) for 5 days showed a significant inhibition of hepatic glutathione-S-transferase (GST) activity; maximum inhibition occurred in 15-day-old rats in which early development of hind limb paralysis was noted. Addition of acrylamide in vitro to the assay system also inhibited GST activity. No changes were observed in oxidized and reduced glutathione contents.     

Effect of styrene on levels of serotonin,noradrenaline, dopamine and activity of acetyl cholinesterase and monoamine oxidase in rat brain

Oral intubation of styrene (1 ml/kg body weight daily) in adult male albino rats for 15 days produced a significant increase in serotonin and nor-adrenaline but no change in dopamine contents in brain. The brain of treated animals also showed a significant decrease in monoamine oxidase (MAO) but no change in acetyl cholinesterase (AChE) activity. The neurotoxic effects of styrene may be mediated through alterations in levels of these biogenic amines in the brain tissue.     

Initial testing of the multitargeted kinase inhibitor pazopanib by the Pediatric Preclinical Testing Program

Pazopanib is an oral angiogenesis inhibitor targeting vascular growth factor receptor-1, -2, and -3, platelet derived growth factor receptor-α, platelet derived growth factor receptor-β, and KIT that has demonstrated activity against a variety of adult cancer xenografts. Pazopanib was tested against a panel of pediatric rhabdomyosarcoma and Ewing sarcoma xenografts at a dose of 108 mg/kg/day or 100 mg/kg twice daily, administered orally for 28 days. While no objective responses were observed, pazopanib induced statistically significant differences in event-free survival compared to controls in approximately one-half of the sarcoma xenograft models tested. Though well tolerated, pazopanib showed limited activity against the sarcoma models evaluated, with the best tumor responses being growth delay.