Inhibition of protein synthesis in lettuce (Latuca sativa L.) by allelopathic compounds

The effects of ferulic, cinnamic, and ellagic acids on the development of roots and protein synthesis in lettuce seedlings (Latuca sativa L., variety of Black Seeded Simpson) are reported here. Both ferulic and cinnamic acids were found to inhibit protein synthesis of the seedlings either when added from the beginning of the germination period, or when added for a short period of time to seedlings which had already germinated under control conditions. Ellagic acid, at the same pH and osmotic concentrations as the effective inhibitors, was completely ineffective in inhibiting either growth of roots or protein synthesis. It is shown that utilization of [¹⁴C] amino acid incorporation into seedlings appears to be a sensitive, reliable, and appropriate indicator of allelopathic inhibition of plant growth. Utilizing this method, it should be possible to determine if the effect on protein synthesis by putative allelopathic compounds is a general phenomenon and may, in turn, help to elucidate the role of these compounds.     

Preliminary Evidence Supporting the Ability of Hermatypic Corals to Affect Adversely Larvae and Early Settlement Stages of Hard Coral Competitors

Crude, aqueous extracts of five species of hermatypic coral from three scleractinian families were assayed for bioactivity against the early life stages of scleractinian corals. At concentrations between 62.5 and 250 μg/ml, extracts of all species were lethal to at least three of the five species of coral planulae larvae tested. To test for behavioral changes, extracts from four species were tested on planulae of the scleractinian Pocillopora damicornis. All four caused immediate but reversible behavioral aberrations in the larvae at concentrations as low as 7.8 μg/ml. To determine the effects on newly settled corals, postmetamorphosis juveniles (spat) of P. damicornis were exposed to extracts from four hermatypic species. They were either killed or suffered a reduction in growth rates. If released under natural conditions, substances with lethal or sublethal activities against the early life stages of other scleractinians could allow hermatypic corals to influence patterns of scleractinian recruitment, thus playing a role in ordering coral communities.     

Adhesion of extrusion‐coated polymer sealing layers to a fiber‐based packaging material with an atomic layer deposited aluminum oxide surface coating

Adhesion of extrusion‐coated polymer sealing layers on an atomic layer deposited (ALD) aluminum oxide (Al₂O₃) surface coating was investigated with a view to gain information on the applicability of ALD deposited barrier layers in fiber‐based packaging materials. The polymers used for the sealing layer were low density polyethylene (LDPE), polyethylene terephthalate (PET), and polylactide (PLA). They were extrusion‐coated onto the ceramic side of paper/PET/Al₂O₃ substrates, where the Al₂O₃ layer was a few tens of nanometers thick. According to the results, good adhesion was obtained for LDPE coating, whereas the other coatings showed a considerable lack of adhesion. Presumably, the oxidation faced by LDPE in the air gap of the extrusion‐coating process was able to create an extensive number of reactive sites that strongly bonded with the hydroxyl groups on the oxide surface of the substrate. With the PET and PLA coatings, such oxidation did not occur and the adhesion obtained remained at a relatively poor level. With all of the coatings, the adhesion levels were improved using corona discharge equipment as a pretreatment prior to the extrusion‐coating process. POLYM. ENG. SCI., 52:1985–1990, 2012. © 2012 Society of Plastics Engineers     

Comparison of carbon nanotube modified electrodes for photovoltaic devices

Substrates with four different nanotube modifications have been prepared and their electron transport properties measured. Two modification techniques were compared; covalent chemical attachment of both single and multi-walled carbon nanotubes to transparent conductive (fluorine doped tin oxide) glass surfaces and chemical vapour deposition (CVD) growth of both single and multi-walled carbon nanotubes on highly doped conductive silicon wafers. These carbon nanotube modified substrates were investigated using scanning electron microscopy and substrates with nanotubes grown via CVD have a much higher density of nanotubes than substrates prepared using chemical attachment. Raman spectroscopy was used to verify that nanotube growth or attachment was successful. The covalent chemical attachment of nanotubes was found to increase substrate electron transfer substantially compared to that observed for the bare substrate. Nanotube growth also enhanced substrate conductivity but the effect is smaller than that observed for covalent attachment, despite a lower nanotube density in the attachment case. In both modification techniques, attachment and growth, single-walled carbon nanotubes were found to have superior electron transfer properties. Finally, solar cells were constructed from the nanotube modified substrates and the photoresponse from the different substrates was compared showing that chemically attached single-walled nanotubes led to the highest power generation.     

Thermodynamics of high-temperature aluminum,zirconium, and yttrium hydroxide and oxyhydroxide vapor species

Thermodynamic parameters are reported for gaseous hydroxides and oxyhydroxides of Al, Zr, and Y. The structures and vibrational frequencies are calculated using density functional theory with the B3LYP functional. This yields entropies at 298.15 K and heat capacities. The enthalpies are calculated from appropriate reactions and the CCSD(T) (Coupled Cluster, Singles, Doubles, and perturbative Triples) approach. The hydroxide groups are treated as hindered rotors for all species. The results are compared to the limited experimental and theoretical calculations for these species. Finally, the data are put into a database for a free-energy minimizer and the vapor pressures for each species are compared.     

Nitrate leaching in temperate agroecosystems: sources, factors and mitigating strategies

Nitrate (NO₃ ^–) leaching from agriculturalproduction systems is blamed for the rising concentrations ofNO₃ ^– in ground- and surface-waters around the world.This paper reviews the evidence of NO₃ ^– leachinglosses from various land use systems, including cut grassland, grazed pastures,arable cropping, mixed cropping with pasture leys, organic farming,horticultural systems, and forest ecosystems. Soil, climatic and managementfactors which affect NO₃ ^– leaching are discussed.Nitrate leaching occurs when there is an accumulation ofNO₃ ^– in the soil profile that coincides with or isfollowed by a period of high drainage. Therefore, excessive nitrogen (N)fertilizer or waste effluent application rates or N applications at the wrongtime (e.g. late autumn) of the year, ploughing pasture leys early in the autumn,or long periods of fallow ground, can all potentially lead to highNO₃ ^– leaching losses. N returns in animal urine havea major impact on NO₃ ^– leaching in grazed pastures.Of the land use systems considered in this paper, the potential for causingNO₃ ^– leaching typically follow the order: forest< cut grassland < grazed pastures, arable cropping < ploughing ofpasture < market gardens. A range ofmanagement options to mitigate NO₃ ^– leaching isdescribed, including reducing N application rates, synchronizing N supply toplant demand, use of cover crops, better timing of ploughing pasture leys,improved stock management, precision farming, and regulatory measures. This isfollowed by a discussion of future research needs to improve our ability topredict and mitigate NO₃ ^– leaching.     

Aerosol and Precipitation Chemistry at a Remote Himalayan Site in Nepal

As a part of a year long aerosol measurement program in the Nepal Himalayas, a series of 12 h samples of aerosol and event-based samples of precipitation were collected in postmonsoon, 1996; premonsoon, 1997; and monsoon, 1997. Results show that diurnal variations in the regional valley wind system are responsible for variations in the major ion (Na + , NH 4 + , K + , Mg 2+ , Ca 2+ , Cl - , NO 3 - , and SO 4 -2 ) concentrations in the aerosol. On time scales greater than a day, changes in atmospheric circulation and associated changes in the precipitation regime have an important effect on aerosol ion concentrations. Periods of high major ion concentration in the aerosol generally coincide with similar periods in precipitation chemistry, although a linear relationship between concentrations in these 2 media is not robust due to limited data. High scavenging ratio values are found for all species except SO 4 2- . Nitrate, Cl - , and NH 4 + are enriched in the precipitation compared to the aerosol, implying the presence of gaseous acidic species (HNO 3 and HCl) and gaseous NH 3 in the air. Ammonium was also enriched with respect to SO 4 2- in aerosol during a dry episode in the monsoon season. This may represent relatively local sources of NH 3 (from neighboring villages) and was not scavenged due to the lack of precipitation. Empirical orthogonal function (EOF) analysis clearly shows the presence of 2 dominant pollutant transport mechanisms for the premonsoon and monsoon seasons (i.e., valley wind system and monsoon circulation). Although physically different, these 2 transport mechanisms follow similar transport pathways and transport aerosol into the Himalayas from similar source regions. Further, EOF analysis suggests a southerly maritime signal in the aerosol during monsoon and a more distant westerly maritime signal during premonsoon. Our results support the potential for using glaciochemical records from the Himalayas to investigate variations in the strength of past monsoon circulation and westerly disturbances.     

Polyglycolide‐based blends for drug delivery: A differential scanning calorimetry study of the melting behavior

The melting behavior of polyglycolide (PGA) with eight other biodegradable polymers was investigated to determine whether forming a blend could be used as a method of lowering the melting point of PGA. Blends were prepared by melt processing in differential scanning calorimetry (DSC) pans and were then analyzed by DSC. In every case, a comparison of the blend DSC plot with those of the two individual components showed that the melting behavior of PGA remained unchanged by blending. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2937–2939, 2003     

Degradation and drug‐release studies of a poly(glycolide‐co‐trimethylene carbonate) copolymer (Maxon)

Poly(glycolide‐co‐trimethylene carbonate) is available commercially as a monofilament suture known as Maxon. The literature has shown that Maxon sutures possess a slow degradation rate of about 7 months and exhibit relatively high mechanical strength in comparison with other absorbable sutures. However, very few articles are available on the degradation of unoriented Maxon. This study was designed to explore the chemical and physical aspects of the degradation of unoriented Maxon and its potential as a drug‐release device. Several analytical techniques were used, including mass measurements, simultaneous small‐angle X‐ray scattering and wide‐angle X‐ray scattering, and thermoporometry. Magnetic resonance imaging and drug‐release measurements were carried out with UV spectroscopy. The results suggest that unoriented suture‐based Maxon undergoes multiple stages of hydrolytic degradation, which involve hydration, and active and postactive periods. The drug‐release mechanism is controlled by diffusion in the early degradation stages and polymer erosion in the later stages of release. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 475–486, 2005     

Identifying Candidate Protein Markers of Acute Kidney Injury in Acute Decompensated Heart Failure

One-quarter of patients with acute decompensated heart failure (ADHF) experience acute kidney injury (AKI)—an abrupt reduction or loss of kidney function associated with increased long-term mortality. There is a critical need to identify early and real-time markers of AKI in ADHF; however, to date, no protein biomarkers have exhibited sufficient diagnostic or prognostic performance for widespread clinical uptake. We aimed to identify novel protein biomarkers of AKI associated with ADHF by quantifying changes in protein abundance in the kidneys that occur during ADHF development and recovery in an ovine model. Relative quantitative protein profiling was performed using sequential window acquisition of all theoretical fragment ion spectra–mass spectrometry (SWATH–MS) in kidney cortices from control sheep (n = 5), sheep with established rapid-pacing-induced ADHF (n = 8), and sheep after ~4 weeks recovery from ADHF (n = 7). Of the 790 proteins quantified, we identified 17 candidate kidney injury markers in ADHF, 1 potential kidney marker of ADHF recovery, and 2 potential markers of long-term renal impairment (differential abundance between groups of 1.2–2.6-fold, adjusted p < 0.05). Among these 20 candidate protein markers of kidney injury were 6 candidates supported by existing evidence and 14 novel candidates not previously implicated in AKI. Proteins of differential abundance were enriched in pro-inflammatory signalling pathways: glycoprotein VI (activated during ADHF development; adjusted p < 0.01) and acute phase response (repressed during recovery from ADHF; adjusted p < 0.01). New biomarkers for the early detection of AKI in ADHF may help us to evaluate effective treatment strategies to prevent mortality and improve outcomes for patients.