bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Alternative Method for Measurement of Airborne Sound Insulation
Authors: Lundberg Karl-Ola 
Published: October 2002

A method for determination of the transmission coefficient from Complex Modulation Transfer Functions CMTF:s based on measured impulse-responses is shown. In the method a separate measurement of the equivalent sound absorption area is not needed in contrast to in the standardised measurement. By averaging over a number of estimates of the impulse-response the influence of background noise can be reduced substantially, implying that low-power sources can be used. A model for the power balance in the receiving room with time-varying power is considered. In the model the quotient of the receiving room intensity and the source room intensity has one pole, which is proportional to the equivalent sound absorption area in the receiving room, and a gain, proportional to the transmission coefficient. In the physical system the power can be time-varied by letting the system excitation signal consist of random noise modulated with a deterministic time-varying function. However, since the ensemble average of the squared response is proportional to the squared impulse-response convolved with the squared modulating function, random excitation is avoided and replaced by impulse-response measurements. The quotient of intensities in the model is in the physical system a quotient of CMTF:s. Experiments are carried out in an airborne sound insulation laboratory. For comparison, standardised measurements are also carried out. It is found that the presented method gives as result comparatively small transmission coefficients, though the relative differences are small. By refining the power balance model by introducing an energy propagation time delay, and selecting an appropriate delay, the differences were diminished.
A comparative study on the tubes and feeding behaviour of eight species of corophioid Amphipoda and their bearing on phylogenetic relationships within the Corophioidea
Authors: Dixon I. M. T. , Moore P. G. 
Published: October 2002

Observations are presented on mouthpart functional morphology, and on feeding, grooming and defaecatory behaviour of eight species of corophioid Amphipoda, viz.Corophium bonnellii,Lembos websteri,Aora gracilis,A. spinicornis,Gammaropsis nitida,Ericthonius punctatus,Jassa falcataandJ. marmorata. These data are considered in relation to tube structure and amphipod posture in relation to the tube. All these species occupy double-ended cylindreical tubes made from ‘amphipod silk’ secreted by the third and fourth preraeopods, incorporating sediment and other debris to varying degrees. Uniquely among this set of species, however,E. punctatushas a tube that is architecturally distinct. It tapers along its length and has a distinctive oblique main entrance at its widest end. This end is used preferentially. The other species studied use either opening with equal facility. Such a feature is adaptive in facilitating deployment of the antennae and shielding the head ofE. punctatus.Two groupings of species are propose: group A which feed inside their tube using pleopod-induced through-tube currents, and group B which feed outside or at the entrance to their tube using external water currents. Group A includesC. bonnellii,L. websteriand theAoraspecies. Group B includesE. punctatusand theJassaspecies.Gammaropsis nitidaexhibits traits from both groups, adding weight to its perceived status as a genus representative of the stem corophioid. The ischyrocerid habit of externalizing food-gathering may be regarded as the first step along an evolutionary line leading to the rod-building podocerid types and ultimately towards the caprellids. All species examined show a degree of flexibility in their feeding habits which helps to explain the success of this taxon, which has radiated into a great diversity of aquatic biotopes.
Adapting and improving crops: the endless task
Authors: Evans L. T. 
Published: October 2002

The Malthusian prognosis has been undermined by an exponential increase in world food supply since 1960, even in the absence of any extension of the arable area. The requisite increases in yield of the cereal staples have come partly from agronomic intensification, especially of nitrogenous fertilizer use made possible by the dwarfing of wheat and rice, in turn made feasible by herbicide development. Cereal dwarfing also contributed to a marked rise in harvest index and yield potential.
Although there is still scope for some further improvement in harvest index and environmental adaptation, it is not apparent how a doubling of yield potential can be achieved unless crop photosynthesis can be substantially enhanced by genetic engineering. Empirical selection for yield has not enhanced photosynthetic capacity to date, but nitrogenous and other fertilizers have done so, and there is still scope for agronomic increases in yield and for new synergisms between agronomy and plant breeding.
The environmental implications of intensified land use in developing countries
Authors: Tinker P. B. 
Published: October 2002

The major agricultural intensifications in the developed world over the last half century have produced a range of important environmental problems. These include pollution, damage to wildlife and landscape and other issues, both on- and off-site. These are largely being controlled by scientific investigation and Government regulation. As developing countries increase agricultural production over the next 30 years, this may also cause even more serious environmental damage.The paper distinguishes between production-related on-site damage, and off-site and more extensive effects. Both may involve soil and water effects, such as soil erosion, salinization, siltation, eutrophication and loss of water quality. The use of more agrochemicals can damage water quality, health, wildlife and biodiversity. Loss of habitat from the extension of farming is particularly damaging to biodiversity. A developing off-site problem is the production of greenhouse gases by farming systems, including the conversion of forests to farmland. In the future the introduction of genetically engineered species of plants, animals or microbes will need secure control.Work, probably on a catchment basis, is necessary to understand and control these problems. The three main requirements are much better environmental information from the developing world; the selection of environmental indicators to be monitored; and the support of local farmers in protecting the environment. There are encouraging indications of farmer concern and action over obvious on-site damage, but this may not extend to extensive off-site issues. The main danger is that developing food scarcity would cause the environmental issues to be ignored in a race for production.
Genetic information and insurance: some ethical issues
Authors: O'neill Onora 
Published: October 2002

Life is risky, and insurance provides one of the best developed ways of controlling risks. By pooling, and so transferring risks, those who turn out to suffer antecedently uncertain harms can be assured in advance that they will be helped if those harms arise; they can then plan their lives and activities with confidence that they are less at the mercy of ill fortune.
Both publicly organized and commercial insurance can organize the pooling of risk in ways that are beneficial for all concerned. They provide standard ways of securing fundamental ethical values such as solidarity and mutuality. Although policy holders do not know or contract with one another, each benefits from the contribution of others to a shared scheme for pooling and so controlling risk. Although there is a limit to the degree to which commercially–based insurance, where premiums depend on risk level, can go beyond mutuality towards solidarity, in practice it too often achieves a measure of solidarity by taking a broad brush approach to pooling risk
However, the ordinary practices of insurance, and in particular of commercial insurance, also raise ethical questions. These may be put in simple terms by contrasting the way in which an insurance market discriminates between different people, on the basis of characteristics that (supposedly) determine their risk level, and our frequent abhorrence of discrimination, in particular on the basis on religious, racial and gender grounds. Are the discriminations on which insurance practice relies upon as standard acceptable or not?
The increasing availability of genetic information, which testing (of individuals) and screening (of populations) may provide, could lend urgency to these questions. Genetic information may provide a way of obtaining more accurate assessment of individual risks to health and life. This information could be used to discriminate more finely between the risk levels of different individuals, and then to alter the availability and the costs of health, life and unemployment insurance to them. Since all of these forms of insurance bear very directly on the way most people live, it will matter to them how (if at all) insurers take account of genetic information. Will use of this information improve or damage the capacity of insurance to provide confidence in the face of uncertain harms, and help if they happen? Will it discriminate in acceptable or in unacceptable ways? Will it support or damage the sorts of mutuality and solidarity various sorts of insurance schemes have successfully institutionalized?
Voluntary Ethanol Consumption by Mice: Genome-Wide Analysis of Quantitative Trait Loci and Their Interactions in a C57BL/6ByJ × 129P3/J F2Intercross
Authors: Bachmanov Alexander A. , Reed Danielle R. , Li Xia , Li Shanru , Beauchamp Gary K. , Tordoff Michael G. 
Published: October 2002

Consumption of ethanol solutions by rodents in two-bottle choice tests is a model to study human alcohol intake. Mice of the C57BL/6ByJ strain have higher ethanol preferences and intakes than do mice of the 129P3/J strain. F2hybrids between these two strains were phenotyped using two-bottle tests involving a choice between water and either 3% or 10% ethanol. High ethanol preferences and intakes of the B6 mice were inherited as additive or dominant traits in the F2generation. A genome screen using these F2mice identified three significant linkages. Two loci, on distal chromosome 4 (Ap3q) and proximal chromosome 7 (Ap7q), strongly affected 10% ethanol intake and weakly affected 3% ethanol intake. A male-specific locus on proximal chromosome 8 (Ap8q) affected 3% ethanol preference, but not indexes of 10% ethanol consumption. In addition, six suggestive linkages (on chromosomes 2, 9, 12, 13, 17, and 18) affecting indexes of 3% and/or 10% ethanol consumption were detected. The loci with significant and suggestive linkages accounted for 35–44% of the genetic variation in ethanol consumption phenotypes. No additive-by-additive epistatic interactions were detected for the primary loci with significant and suggestive linkages. However, there were a few modifiers of the primary linkages and a number of interactions among unlinked loci. This demonstrates a significant role of the genetic background in the variation of ethanol consumption.[Supplementary material is available online atwww.genome.org.]
A Role for Diacylglycerol Acyltransferase during Leaf Senescence
Authors: Kaup Marianne T. , Froese Carol D. , Thompson John E. 
Published: October 2002

Abstract
Lipid analysis of rosette leaves from Arabidopsis has revealed an accumulation of triacylglycerol (TAG) with advancing leaf senescence coincident with an increase in the abundance and size of plastoglobuli. The terminal step in the biosynthesis of TAG in Arabidopsis is catalyzed by diacylglycerol acyltransferase 1 (DGAT1; EC 2.3.1.20). When gel blots of RNA isolated from rosette leaves at various stages of development were probed with the Arabidopsis expressed sequence tag clone, E6B2T7, which has been annotated as DGAT1, a steep increase in DGAT1 transcript levels was evident in the senescing leaves coincident with the accumulation of TAG. The increase in DGAT1 transcript correlated temporally with enhanced levels of DGAT1 protein detected immunologically. Two lines of evidence indicated that the TAG of senescing leaves is synthesized in chloroplasts and sequesters fatty acids released from the catabolism of thylakoid galactolipids. First, TAG isolated from senescing leaves proved to be enriched in hexadecatrienoic acid (16:3) and linolenic acid (18:3), which are normally present in thylakoid galactolipids. Second, DGAT1 protein in senescing leaves was found to be associated with chloroplast membranes. These findings collectively indicate that diacylglycerol acyltransferase plays a role in senescence by sequestering fatty acids de-esterified from galactolipids into TAG. This would appear to be an intermediate step in the conversion of thylakoid fatty acids to phloem-mobile sucrose during leaf senescence.
Up-Regulation of Phosphoinositide Metabolism in Tobacco Cells Constitutively Expressing the Human Type I Inositol Polyphosphate 5-Phosphatase
Authors: Perera Imara Y. , Love John , Heilmann Ingo , Thompson William F. , Boss Wendy F. 
Published: October 2002

Abstract
To evaluate the impact of suppressing inositol 1,4,5-trisphosphate (InsP3) in plants, tobacco (Nicotiana tabacum) cells were transformed with the human type I inositol polyphosphate 5-phosphatase (InsP 5-ptase), an enzyme which specifically hydrolyzes InsP3. The transgenic cell lines showed a 12- to 25-fold increase in InsP 5-ptase activity in vitro and a 60% to 80% reduction in basal InsP3 compared with wild-type cells. Stimulation with Mas-7, a synthetic analog of the wasp venom peptide mastoparan, resulted in an approximately 2-fold increase in InsP3 in both wild-type and transgenic cells. However, even with stimulation, InsP3 levels in the transgenic cells did not reach wild-type basal values, suggesting that InsP3 signaling is compromised. Analysis of whole-cell lipids indicated that phosphatidylinositol 4,5-bisphosphate (PtdInsP2), the lipid precursor of InsP3, was greatly reduced in the transgenic cells. In vitro assays of enzymes involved in PtdInsP2 metabolism showed that the activity of the PtdInsP2-hydrolyzing enzyme phospholipase C was not significantly altered in the transgenic cells. In contrast, the activity of the plasma membrane PtdInsP 5 kinase was increased by approximately 3-fold in the transgenic cells. In vivo labeling studies revealed a greater incorporation of 32P into PtdInsP2 in the transgenic cells compared with the wild type, indicating that the rate of PtdInsP2 synthesis was increased. These studies show that the constitutive expression of the human type I InsP 5-ptase in tobacco cells leads to an up-regulation of the phosphoinositide pathway and highlight the importance of PtdInsP2 synthesis as a regulatory step in this system.
hpRNA-Mediated Targeting of the Arabidopsis FAD2 Gene Gives Highly Efficient and Stable Silencing
Authors: Stoutjesdijk Peter A. , Singh Surinder P. , Liu Qing , Hurlstone Clive J. , Waterhouse Peter A. , Green Allan G. 
Published: October 2002

Abstract
The endogenous Δ12-desaturase gene (FAD2) in Arabidopsis was targeted for silencing using seed-specific cosuppression (CS), hairpin (HP) RNA (hpRNA), and intron-spliced HP (iHP) constructs. The iHP construct, incorporating the 120-bp 3′-untranslated region of the FAD2 gene, gave the highest degree of silencing. In some iHP lines Δ12-desaturase activity was reduced to levels as low as those in the nullfad2-1 mutant, and every primary transformant showed a pronounced reduction in FAD2 activity. One highly silenced iHP line was propagated for five generations and showed no reversion or diminution in its degree of silencing. About 75% of plants transformed with the HP construct, targeting theFAD2 coding region, gave dramatically reduced Δ12-desaturase activity, whereas approximately 50% of plants transformed with the CS construct, containing the same coding region sequence, showed silencing at a much less profound level. In all three types of constructs, the degree of silencing was increased when the transgenes were homozygous, but this was much more pronounced for the CS constructs. All three types of construct could give a single locus that was capable of effective silencing, but in the one such CS line where this was the case, the locus had a complex insertion pattern. This is consistent with the concept that posttranscriptional gene silencing is induced by double-stranded, or self-complementary, RNA that is formed in cases of CS by complex insertion patterns at a single locus and that the most effective way of generating profoundly silenced plants is by the use of constructs that encode hpRNAs. Furthermore, these results demonstrate for the first time, to our knowledge, that iHP constructs targeted against an endogenous seed-expressed gene are clearly able to generate phenotypic changes that are inherited stably over several generations, making this approach a reliable technique for genetic modification of seed quality and possibly other traits in agricultural plants.
Origins of Phytochrome-Modulated Lhcb mRNA Expression in Seed Plants
Authors: Christensen Steen , Silverthorne Jane 
Published: October 2002

Abstract
The levels of Lhcb mRNA in higher plants are regulated by phytochrome, cryptochrome, and an endogenous circadian oscillator. To determine whether similar regulatory mechanisms operate in the ancient gymnosperm Ginkgo biloba, we measuredLhcb mRNA levels in seedlings in response to different light conditions. Removal of a diurnally oscillating light stimulus caused dampening of maximal Lhcb mRNA accumulation levels, with little change in periodicity. Although low fluence pulses of both red and blue light given to etiolated seedlings caused maximal accumulation of Lhcb mRNAs characteristic of the phasic/circadian response seen in flowering plants, the additional initial acute response seen in flowering plants was absent. The induction of Lhcb gene expression in both cases was at least partially reversible by far-red light, and appeared biphasic over a range of red fluences. Together, these data indicate thatLhcb genes in G. biloba appear to be regulated in a manner similar to that of flowering plants, whereas signaling and attenuation of mRNA levels through the photoreceptor systems and circadian clock show features distinct from those characterized to date. The implications for these findings are discussed in light of the evolution of circadian clock input signaling.
Versatile cloning system for construction of multimeric proteins for use in atomic force microscopy
Authors: Steward Annette , Toca‐Herrera José Luis , Clarke Jane 
Published: October 2002

AbstractThis manuscript introduces a versatile system for construction of multimeric proteins to be used as substrates for atomic force microscopy. The construction makes use of a cassette system that allows modules to be cut and ligated in any combination in eight different positions. The modules can be sequenced in situ after construction. A three‐module fragment can be produced that is of a size amenable to structural and biophysical analysis to check the effect of placing a protein into a multimeric construct. We show that if the parent titin modules are retained in a construct, they can act both as linkers and as an internal standard for the force measurements. Proteins that cannot be expressed solubly in an eight‐module homopolymer have been expressed and subject to force measurements using this system.
Structural and dynamic properties of water around acetylcholinesterase
Authors: Henchman Richard H. , McCammon J. Andrew 
Published: October 2002

AbstractStructural and dynamic properties of water molecules around acetylcholinesterase are examined from a 10‐nsec molecular dynamics simulation to help understand how the protein alters water properties. Water structure is broken down into hydration sites constructed from the water density <3.6 Å from the protein surface. These sites are characterized according to occupancy, number of water neighbors, hydrogen bonds, dipole moment, and residence time. The site description provides a convenient means to describe the extent and localization of these properties. Determining the network of paths that waters follow from site to site and measuring the rate of flow of waters from the sites to the bulk make it possible to quantitatively study the time scales and paths that water molecules follow as they move around the protein.
Antibound States and Exponentially Decaying Sturm–Liouville Potentials
Authors: Eastham M. S. P. 
Published: October 2002

We consider the Sturm–Liouville equationy″(x)+{λ−q(x)}y(x)=0 (0⩽x<∞) (1.1)with a boundary condition at x = 0 which can be either the Dirichlet conditiony(0)=0 (1.2)or the Neumann conditiony′(0)=0 (1.3)As usual, λ is the complex spectral parameter with 0 ⩽ arg λ < 2π, and the potential q is real‐valued and locally integrable in [0, ∞).
Importance of the Fourth Alpha-Helix within the CAP Homology Domain of Type II Topoisomerase for DNA Cleavage Site Recognition and Quinolone Action
Authors: Strumberg Dirk , Nitiss John L. , Dong Jiaowang , Walker Jerrylaine , Nicklaus Marc C. , Kohn Kurt W. , Heddle Jonathan G. , Maxwell Anthony , Seeber Siegfried , Pommier Yves 
Published: October 2002

ABSTRACT

We report that point mutations causing alteration of the fourth alpha-helix (α4-helix) of the CAP homology domain of eukaryotic (
Saccharomyces cerevisiae
) type II topoisomerases (Ser
740
Trp, Gln
743
Pro, and Thr
744
Pro) change the selection of type II topoisomerase-mediated DNA cleavage sites promoted by Ca
2+
or produced by etoposide, the fluoroquinolone CP-115,953, or mitoxantrone. By contrast, Thr
744
Ala substitution had minimal effect on Ca
2+
- and drug-stimulated DNA cleavage sites, indicating the selectivity of single amino acid substitutions within the α4-helix on type II topoisomerase-mediated DNA cleavage. The equivalent mutation in the gene for
Escherichia coli
gyrase causing Ser
83
Trp also changed the DNA cleavage pattern generated by Ca
2+
or quinolones. Finally, Thr
744
Pro substitution in the yeast type II topoisomerase rendered the enzyme sensitive to antibacterial quinolones. This study shows that the α4-helix within the conserved CAP homology domain of type II topoisomerases is critical for selecting the sites of DNA cleavage. It also demonstrates that selective amino acid residues in the α4-helix are important in determining the activity and possibly the binding of quinolones to the topoisomerase II-DNA complexes.
Oxidative Stress Increases Susceptibility of
Mycobacterium tuberculosis
to Isoniazid
Authors: Bulatovic Vanja M. , Wengenack Nancy L. , Uhl James R. , Hall Leslie , Roberts Glenn D. , Cockerill Franklin R. , Rusnak Frank 
Published: October 2002

ABSTRACT

Isoniazid is a first-line antibiotic used in the treatment of infections caused by
Mycobacterium tuberculosis
. Isoniazid is a prodrug requiring oxidative activation by the catalase-peroxidase hemoprotein, KatG. Resistance to isoniazid can be obtained by point mutations in the
katG
gene, with one of the most common being a threonine-for-serine substitution at position 315 (S315T). The S315T mutation is found in more than 50% of isoniazid-resistant clinical isolates and results in an ≈200-fold increase in the MIC of isoniazid compared to that for
M. tuberculosis
H37Rv. In the present study we investigated the hypothesis that superoxide plays a role in KatG-mediated isoniazid activation. Plumbagin and clofazimine, compounds capable of generating superoxide anion, resulted in a lower MIC of isoniazid for
M. tuberculosis
H37Rv and a strain carrying the S315T mutation. These agents did not cause as great of an increase in isoniazid susceptibility in the mutant strain when the susceptibilities were assessed by using the inhibitory concentration that causes a 50% decrease in growth. These results provide evidence that superoxide can play a role in isoniazid activation. Since clofazimine alone has antitubercular activity, the observation of synergism between clofazimine and isoniazid raises the interesting possibility of using both drugs in combination to treat
M. tuberculosis
infections.