Water—The Silent Messenger between Cause and Effect in Environmental Problems

ABSTRACT

Ten years after the Stockholm Conference on the Human Environment, there has been an array of meetings discussing the environmental problems emerging for the 80s. One of the most encouraging results of the 70s is the power of public opinion. This stresses the crucial importance of broad public understanding in arriving at constructive environmental management. To facilitate such understanding, the author calls for a broader use of a conceptual framework based on the biosphere as providing man's life-support systems, and clearer attention to the roles of water in these systems. Environmental management is the problem of striking the right balance between necessary manipulations of these systems, and negative side-effects produced. Water scientists should contribute to a clearer understanding of water's many roles in the ecosystem, including its role as a silent messenger, typing together cause and effect in environmental manipulations.     

Stable linker peptides for a cellulose-binding domain-lipase fusion protein expressed in Pichia pastoris

Fusion proteins composed of a cellulose-binding domain fromNeocallimastix patriciarum cellulase A and Candida antarcticalipase B were constructed using different linker peptides. Theaim was to create proteolytically stable linkers that were ableto join the functional modules without disrupting their function.Six fusion variants containing linkers of 4–44 residueswere expressed in Pichia pastoris and analysed. Three variantswere found to be stable throughout 7-day cultivations. The cellulose-bindingcapacities of fusion proteins containing short linkers wereslightly lower compared with those containing long linkers.The lipase-specific activities of all variants, in solutionor immobilized on to cellulose, were equal to that of the wild-typelipase.     

Identification of the Sex Pheromone of the Swede Midge, <Emphasis Type="Italic">Contarinia nasturtii</Emphasis>

Coupled gas chromatographic–electroantennographic detection analyses of ovipositor extracts of calling Contarinia nasturtii females revealed two compounds that elicited responses from antennae of male midges. Using synthetic reference samples, these components were identified by gas chromatography–mass spectrometry and enantioselective GC as (2S,9S)-diacetoxyundecane and (2S,10S)-diacetoxyundecane. In addition, trace amounts of 2-acetoxyundecane were found in ovipositor extracts, and the (S)-enantiomer was synthesized. When tested in the wind tunnel, a blend of 5ng (2S,9S)-diacetoxyundecane and 10 ng (2S,10S)-diacetoxyundecane (mimicking the ratio found in the extracts) did not attract any of the males tested, but when 0.1 ng (S)-2-acetoxyundecane was added to the blend, 86.8% of the males were attracted to the bait. Three-component blends with lower or higher relative concentrations than 1% of (S)-2-acetoxyundecane [relative to (2S,10S)-diacetoxyundecane] were less attractive. In a field trapping experiment with released laboratory-reared C. nasturtii adults, traps baited with 500:1000:10 ng of (2S,9S)-diacetoxyundecane/(2S,10S)-diacetoxyundecane/(S)-2-acetoxyundecane applied to rubber septa or dental cotton rolls were tested. Traps without dispensers were used as controls. All three treatments were tested at 20 and 50 cm above ground. The estimated recapture rate was 30–50%, and 81.9% of the recaptured males were caught in traps positioned at 20 cm above ground, and 88.4% in traps with dental cotton rolls as dispensers.     

Direct molecular analysis of whole-body animal tissue sections by imaging MALDI mass spectrometry

Imaging mass spectrometry (IMS) that utilizes matrix-assisted laser desorption/ionization (MALDI) technology can provide a molecular ex vivo view of resected organs or whole-body sections from an animal, making possible the label-free tracking of both endogenous and exogenous compounds with spatial resolution and molecular specificity. Drug distribution and, for the first time, individual metabolite distributions within whole-body tissue sections can be detected simultaneously at various time points following drug administration. IMS analysis of tissues from 8 mg/kg olanzapine dosed rats revealed temporal distribution of the drug and metabolites that correlate to previous quantitative whole-body autoradiography studies. Whole-body MALDI IMS is further extended to detecting proteins from organs present in a whole-body sagittal tissue section. This technology will significantly help advance the analysis of novel therapeutics and may provide deeper insight into therapeutic and toxicological processes, revealing at the molecular level the cause of efficacy or side effects often associated with drug administration.     

Commercial spread optimization using experimental design and sensory data

The cost and quality of food products are issues that concern both the consumer and producer. In this research, the process used for the production of a commercial spread was subjected to a statistical experimental design for the purpose of reducing the cost of production while maintaining or improving the sensory quality. Three factors—the amount of oil added (x ₁), the speed of puddling (x ₂), and the temperature treatment (A or B; x ₃)—were varied according to a full-factorial design at two levels. The experiments were performed over 2 d, and the factorial design was complemented with three replicates for temperature treatments A and B, which were performed on different days. The products were evaluated with both sensory and physicochemical measurements. Special attention was paid to the hardness of the product since it was permissible to reduce it slightly. In contrast, sensory quality aspects of the product including butter-aroma and off-flavor, as well as other quality properties such as spreadability, shine, and meltability, had to be maintained at the present level or improved. Statistical evaluation of the data showed that it was possible to add high amounts of oil (x ₁) without impairing the sensory quality of the product and, hence, reduce the cost of production. The hardness of the product was also slightly reduced when using the high level of oil. In maintaining other sensory qualities such as shine and spreadability at the present levels, the choice of temperature treatment (x ₃) was important.     

Optimized gold nanoshell ensembles for biomedical applications

We theoretically study the properties of the optimal size distribution in the ensemble of hollow gold nanoshells (HGNs) that exhibits the best performance at in vivo biomedical applications. For the first time, to the best of our knowledge, we analyze the dependence of the optimal geometric means of the nanoshells’ thicknesses and core radii on the excitation wavelength and the type of human tissue, while assuming lognormal fit to the size distribution in a real HGN ensemble. Regardless of the tissue type, short-wavelength, near-infrared lasers are found to be the most effective in both absorption- and scattering-based applications. We derive approximate analytical expressions enabling one to readily estimate the parameters of optimal distribution for which an HGN ensemble exhibits the maximum efficiency of absorption or scattering inside a human tissue irradiated by a near-infrared laser.     

Biodegradable lactone copolymers. II. Hydrolytic study of ε-caprolactone and lactide copolymers

Copolymers of ε-CL/L-LA and ε-CL/DL-LA were allowed to age in a buffer solution of pH 7 at 23 and 37°C. The effects of time and temperature on the rate of hydrolysis were examined by various techniques including weighing (water absorption and weight loss), SEC (molecular weight and polydispersity), and DSC (thermal properties). For comparison, the hydrolytic behavior of PLLA, PDLLA, and commercial PCL homopolymers was investigated by the same methods. SEC measurements showed that molecular weights of the copolymers and PLA homopolymers started to decrease during the first week of hydrolysis, but significant mass losses occurred only much later. As expected, there was no change in either molecular weight or mass of PCL during the hydrolysis study. The kinetic results for copolymers and homopolymers were calculated to study the degradation mechanism. During hydrolysis, the crystallinity of the initially semicrystalline copolymers increased and some crystallinity appeared in the initially amorphous L-LA-containing copolymers. © 1996 John Wiley & Sons, Inc.     

Growth and characterization of n-type InP/InGaAs quantum well infrared photodetectors for response at 8.93 µm

We present experimental results on the growth and characterization of n-type InGaAs/InP quantum-well intersubband photodetectors for use at 8.93 μm. High-quality InGaAs/InP multiple quantum wells were grown by gas source molecular beam expitaxy, and then characterized by double-crystal x-ray diffraction and cross-sectional transmission electron microscopy. Based upon the structural parameters determined by these methods, the photocurrent response spectra were simulated using a six-band effective bond-orbital model. The theoretical results are in excellent agreement with experimental data. Additional important device characteristics such as dark current, spectral response, and absolute responsivity are also presented.     

Radiation enhancement in doped AlGaN-structures upon optical pumping

Spectral characteristics of spontaneous and stimulated luminescence have been studied for molecular beam epitaxy synthesized Al _x Ga_1–x N/AlN solid solutions with x = 0.5 and 0.74 upon optical pumping by pulse laser radiation with λ = 266 nm. Broadband radiation spectra with a width of ~260 THz for Al_0.5Ga_0.5N and ~360 THz for Al_0.74Ga_0.26N have been obtained. The measured enhancement factors are g ≈ 70 cm^–1 for Al_0.5Ga_0.5N at λ ≈ 528 nm and g ≈ 20 cm^–1 for Al_0.74Ga_0.26N at λ ≈ 468 nm.     

Clustered sampling improves random subspace brain mapping

Intuitive and efficient, the random subspace ensemble approach provides an appealing solution to the problem of the vast dimensionality of functional magnetic resonance imaging (fMRI) data for maximal-accuracy brain state decoding. Recently, efforts to generate biologically plausible and interpretable maps of brain regions which contribute information to the ensemble decoding task have been made and two approaches have been introduced: globally multivariate random subsampling and locally multivariate Monte Carlo mapping. Both types of maps reflect voxel-wise decoding accuracies averaged across repeatedly randomly sampled voxel subsets, highlighting voxels which consistently participate in high-classification subsets. We compare the mapping sensitivities of the approaches on realistic simulated data containing both locally and globally multivariate information and demonstrate that utilizing the inherent volumetric nature of fMRI through clustered Monte Carlo mapping yields dramatically improved performances in terms of voxel detection sensitivity and efficiency. These results suggest that, unless a priori information specifically dictates a global search, variants of clustered sampling should be the priority for random subspace brain mapping.