bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive Oxygen Species, Aging, and Antioxidative Nutraceuticals
Authors: Lee J. , Koo N. , Min D. B.
Published: November 2006

The important roles of reactive oxygen species in diseases related to aging and the necessity and benefits of antioxidative nutraceuticals in the prevention of diseases and promotion of healthy aging have been extensively reported in recent years. Oxygen is an essential component of living organisms. The generation of reactive oxygen species such as superoxide anion, hydrogen peroxide, hydroxyl radicals, and singlet oxygen is inevitable in aerobic metabolism of the body. Reactive oxygen species cause lipid oxidation, protein oxidation, DNA strand break and base modification, and modulation of gene expression. In the past several years, unprecedented progress has been made in the recognition and understanding of roles of reactive oxygen species in many diseases. These include atherosclerosis, vasospasms, cancers, trauma, stroke, asthma, hyperoxia, arthritis, heart attack, age pigments, dermatitis, cataractogenesis, retinal damage, hepatitis, liver injury, and periodontis, which are age‐related. The body protects itself from the potential damages of reactive oxygen species. Its first line of defense is superoxide dismutases, glutathione peroxidases, and catalase. Scientists have indicated that antioxidant nutraceuticals supplied from daily diets quench the reactive oxygen species or are required as cofactors for antioxidant enzymes. Nutraceuticals play significant roles in the prevention of a number of age‐related diseases and are essential for healthy aging. Epidemiological studies also reported the relevance of antioxidative nutraceuticals to health issues and the prevention of age‐related diseases. Health‐conscious consumers have made antioxidative nutraceuticals the leading trend in the food industry worldwide in recent years.
Inflammatory Process and Molecular Targets for Antiinflammatory Nutraceuticals
Authors: Huang M.‐T. , Ghai G. , Ho C.‐T.
Published: November 2006

Intense interest in nutraceuticals and their potential benefits has created the need to review the existing scientific information on their effect in preventing and managing inflammation that accompanies most chronic diseases. This article reviews the basic mechanisms of inflammation and the potential of 9 nutraceuticals to be effective as chronic disease preventive agents. Furthermore, the article emphasizes studies in which nutraceuticals are shown to be effective in preventing inflammation and mentions other molecular targets that can be of use in the future. The effects of the following nutraceuticals: α‐tocopherol, ascorbic acid, curcumin, resveratrol, (‐)‐epigallocatechin gallate, theaflavin, genistein, omega‐3 fatty acids, and lycopene on reactive oxygen species scavenging ability, as well as proinflammatory targets, such as tumor necrosis factor α interleukin‐1, interleukin‐1β, nuclear factor kappa B, cellular and adhesion molecules, cyclooxygenase‐2, inducible nitric oxide synthase, 5‐lipoxygenase (5‐LOX), phospholipase A2, reactive oxygen species generating enzymes are discussed.
A Perspective on Developing and Marketing Food Products to Meet Individual Needs of Population Segments
Authors: Mehrotra I.
Published: November 2006

The promise of evolving research in the area of genomics suggests a move toward an individualized or customized approach to the diet. However, these advances in research do not come without complexities and raise much tougher questions, such as how will the food industry view this as an opportunity? What challenges will it face? Will it play a pivotal role?
Individualization of Flavor Preferences: Toward a Consumer‐centric and Individualized Aroma Science
Authors: Yeretzian C. , Pollien P. , Lindinger C. , Ali S.
Published: November 2006

Personal dietary choices are largely based on flavor preferences. Thus understanding individual flavor perception and preference is vital to understanding the basis of human diet selection. We have developed novel tools to measure in real time and at an individual level volatile aroma compounds delivered breath‐by‐breath to the nose while eating and drinking. The same food may deliver different aromas to different people, due the specificities of their in‐mouth environment (inter‐individual differences). Moreover, a person may eat a given food in a different manner, leading to variations in the aroma profile reaching the nose (intra‐individual differences). Understanding the basis of these differences opens the door to an individualized aroma science and the road to delivering nutritional value and health through products consumers prefer. The challenge to the food industry is to align what the consumer wants with what the consumer needs, delivering nutritional value and health through products they prefer.
Low‐calorie Sweeteners and Other Sugar Substitutes: A Review of the Safety Issues
Authors: Kroger Manfred , Meister Kathleen , Kava Ruth
Published: November 2006

Sugar‐free or reduced‐sugar foods and beverages are very popular in the United States and other countries, and the sweeteners that make them possible are among the most conspicuous ingredients in the food supply. Extensive scientific research has demonstrated the safety of the 5 low‐calorie sweeteners currently approved for use in foods in the United States–acesulfame K, aspartame, neotame, saccharin, and sucralose. A controversial animal cancer study of aspartame conducted using unusual methodology is currently being reviewed by regulatory authorities in several countries. No other issues about the safety of these 5 sweeteners remain unresolved at the present time. Three other low‐calorie sweeteners currently used in some other countries–alitame, cyclamate, and steviol glycosides–are not approved as food ingredients in the United States. Steviol glycosides may be sold as a dietary supplement, but marketing this product as a food ingredient in the United States is illegal. A variety of polyols (sugar alcohols) and other bulk sweeteners are also accepted for use in the United States. The only significant health issue pertaining to polyols, most of which are incompletely digested, is the potential for gastrointestinal discomfort with excessive use. The availability of a variety of safe sweeteners is of benefit to consumers because it enables food manufacturers to formulate a variety of good‐tasting sweet foods and beverages that are safe for the teeth and lower in calorie content than sugar‐sweetened foods.
Distribution of Genotypes of Porphyromonas gingivalis in Type 2 Diabetic Patients with Periodontitis in Mexico
Authors: Davila‐Perez Claudia , Amano Atsuo , Alpuche‐Solis Angel Gabriel , Patiño‐Marin Nuria , Pontigo‐Loyola America Patricia , Hamada Shigeyuki , Loyola‐Rodriguez Juan Pablo
Published: November 2006

Objective: To determine and compare the distribution of Porphyromonas gingivalis fimA genotypes in type 2 diabetes mellitus (T2DM) patients affected by periodontitis, using non‐diabetic subjects with and without periodontitis as control groups.

Material and Methods: This study involved 75 subjects divided into three groups of 25 subjects each: Group 1 (non‐T2DM without periodontitis), Group 2 (non‐T2DM with periodontitis) and Group 3 (T2DM with periodontitis). The outcome variable was periodontitis, and explanatory variables were age, sex, T2DM and specific P. gingivalis fimA genotypes.

Results: In non‐T2DM subjects with healthy periodontal tissues, type I fimA was the most frequently detected individually (40%) or in combinations (40%). In non‐T2DM subjects with periodontitis, the most frequently detected type was Ib individually (20%) or in combinations (36%). In T2DM patients with periodontitis, the most frequently detected types were types I (20%) and III (20%), but there was no statistical difference (p>0.05) with non‐T2DM periodontitis subjects.

Conclusions: Type I genotype was more frequently detected in periodontally healthy sites from non‐T2DM subjects than in periodontitis sites from either subjects with or without T2DM. However, in sites affected by periodontitis from T2DM subjects the predominating types were I and III, which are less virulent strains of P. gingivalis.
Meta‐analyses of studies of 0.2% delmopinol mouth rinse as an adjunct to gingival health and plaque control measures
Authors: Addy Martin , Moran John , Newcombe Robert G.
Published: November 2006

Background: Delmopinol is a third‐generation anti‐plaque agent used as a mouthwash to reduce plaque and alleviate gingivitis.

Objective: To create an overview of the anti‐plaque efficacy of 0.2% delmopinol as an adjunct to normal oral hygiene measures by meta‐analysis of completed clinical trials.

Materials and Methods: Eight double‐blind, parallel‐group studies were identified. Study durations ranged from 8 to 24 weeks. Five studies (n=913) involved supervised rinsing; three studies (n=467) involved unsupervised rinsing. These sets of trials were analysed separately and in combination. Efficacy outcomes comprised modified plaque index, modified gingival index (MGI) and gingival bleeding on probing (BOP).

Results: Delmopinol 0.2% was superior to placebo for the reduction of plaque scores in both sets of studies. Effects on MGI and BOP were also better with delmopinol 0.2% than with placebo. In most instances, 95% confidence intervals were wholly in favour of delmopinol. Pooled analysis of all eight studies confirmed statistically significant effects of delmopinol 0.2% compared with placebo (p<0.00001). Delmopinol met the efficacy criteria of the American Dental Association in studies of extended duration.

Conclusion: Delmopinol 0.2% mouthwash is effective as an adjunct measure for reducing plaque burden and indices of gingivitis, whether or not it is used under supervision.
Plasma levels of tumour necrosis factor‐α in patients with chronic periodontitis and type 2 diabetes
Authors: Engebretson S. , Chertog R. , Nichols A. , Hey‐Hadavi J. , Celenti R. , Grbic J.
Published: November 2006

Objectives: Studies suggest that elevated circulating tumour necrosis factor‐α (TNF‐α) may contribute to insulin resistance in patients with type 2 diabetes. The source of plasma TNF has been thought to be adipocytes associated with obesity, but inflammation and infection result in TNF‐α production as well.

Methods: We studied 46 patients with type 2 diabetes and chronic periodontitis to determine the relationship between plasma TNF‐α levels and clinical measures of periodontitis, gingival crevicular fluid (GCF) interleukin‐1β (IL‐1β), plasma endotoxin, serum glucose, and glycated haemoglobin (HbA1c). TNF‐α levels were measured using a high sensitivity enzyme‐linked immunosorbent assay.

Results: TNF‐α showed a significant positive correlation with attachment loss (r=0.40, p=0.009), plasma endotoxin (r=0.33, p=0.03), and GCF IL‐1β (r=0.33, p=0.035), but not probing depth (r=0.28, p=0.07), bleeding on probing (r=0.30, p=0.053), plaque index (r=0.22, p=0.17), serum glucose, HbA1c (r=0.10, p=0.50), or body mass index (r=0.077, p=0.62). A dose–response relationship was observed between periodontitis severity and TNF‐α (p=0.012).

Conclusion: The finding that chronic periodontitis is associated with plasma TNF‐α levels in subjects with type 2 diabetes supports the hypothesis that periodontal infection and inflammation may contribute to insulin resistance.
Postflood movements and population connectivity in gambusia (Gambusia holbrooki)
Authors: Chapman P. , Warburton K.
Published: November 2006

Abstract – A population of the exotic pest fishGambusia holbrookiinhabiting a drainage channel was sampled regularly to record responses to flooding and subsequent population reestablishment. The flood reduced numbers in the channel to near‐zero levels. After remaining very low for 2 months, densities increased steadily through juvenile recruitment and the concentration of fish in drying pools. Tagging revealed that in general, movements between pools separated by only a few metres were relatively limited. There was evidence for habitat segregation and population subdivision, as fish from different pools varied markedly in terms of mean population density, movement behaviour, sex and size composition and juvenile recruitment. The most favoured pool was relatively deep, well lit and had the greatest habitat diversity. Gambusia control measures are likely to be most effective if timed to coincide with floods (which reduce local population densities) and/or droughts (which concentrate fish and allow targeting of source populations).
Some impacts of low and medium head weirs on downstream fish movement in the Murray–Darling Basin in southeastern Australia
Authors: O'Connor J. P. , O'Mahony D. J. , O'Mahony J. M. , Glenane T. J.
Published: November 2006

Abstract –  This article reports on the findings of a study undertaken within the Murray‐Darling River Basin in southeastern Australia, which investigated the impact of weirs on downstream fish movement. Downstream fish movement was monitored at Kennedy's Weir (an overshot, 2 m high weir) on the Broken Creek and Torrumbarry Weir (an undershot, 6.5 m high weir) on the Murray River. A trap used to sample Kennedy's Weir indicated that fish travelled downstream over this weir without sustaining injury or death. A follow‐up study, whereby fish were captured below the two respective weirs and translocated upstream where they were radio tagged and released, indicated that while a few fish travelled downstream past the weirs on their return movements back to their home range areas, most were reluctant to do so. This study demonstrates that low‐level weirs may inhibit downstream fish movement, and enhancement of downstream fish passage for potamodromous fish species warrants further investigation.
Errors in ocular index measurements in European eel Anguilla anguilla (L.)
Authors: Acou A. , Poizat G. , Crivelli A.‐J.
Published: November 2006

Abstract –  Knowledge of maturation state of eels (Anguilla anguilla, L.) based on ocular index (OI) serves management and research functions, such as estimating how much silver eel actually could escape from a particular basin or determining more precisely the developmental biology of a particular eels. OI implies the measurements of five variables (total length and eyes diameters) in a formula which can be sensitive to measurement error. To investigate this issue, we carried out a comparative study using 13 European eels harvested in Camargue (Rhône Delta, France) and three replicated measurements by three different observers. The estimated amplitude of OI imprecision at a 95% confidence level was 1.8 whatever eel and observer. Such error may lead to classification problems particularly when OI values are close to the threshold values used to discriminate between yellow and silver stages. This study not only raised the problem of the OI imprecision but also brought up the need to develop standardised protocol for identifying silver eels. To reach this goal, two different ways are proposed in conclusion.
Use of a vertical‐slot fishway by galaxiids in Western Australia
Authors: Morgan D. L. , Beatty S. J.
Published: November 2006

Abstract –  The Goodga River Fishway is the first vertical‐slot fishway in Western Australia and was opened in April 2003 with the aim of increasing the habitat available to two galaxiids; the trout minnow (Galaxias truttaceus), a highly restricted freshwater fish species in Western Australia, and the widespread common jollytail (Galaxias maculatus). The fishway was designed to function during low flows to coincide with the upstream spawning migration of G. truttaceus. Prior to the opening of the fishway, no fish were found above the Goodga River gauging station (weir), which is approximately 2 km upstream of the river's entrance to Moates Lake. Fish migrations were monitored in each season between April 2003 and February 2005. Galaxias truttaceus utilised the fishway in all sampling periods. Adult fish migrated up the fishway prior to spawning, while large numbers of new recruits (small juveniles) negotiated the fishway during November 2003 and 2004. More G. truttaceus and G. maculatus were captured on the fishway during daylight hours compared with the night; however, larger G. truttaceus were more commonly captured at night whereas G. maculatus on the fishway were larger during the day. The fact that fishway utilisation by G. maculatus was consistent during all samples and new recruits migrated during periods of low flow demonstrates the importance of understanding the migration patterns of the target species when designing fishways.
Major difference in mercury concentrations of the African big barb, Barbus intermedius (R.) due to shifts in trophic position
Authors: Desta Z. , Borgstrøm R. , Rosseland B. O. , Gebre‐Mariam Z.
Published: November 2006

Abstract –  The African big barb (Barbus intermedius, R.) from Lake Awassa, Ethiopia is an important fish species, especially with the ongoing decline of the Nile tilapia (Oreochromis niloticus, L.) fishery. Their diet and habitat use was studied using stomach content analyses, stable nitrogen and carbon isotopes, and transect netting. Mercury biomagnification was also determined. The big barb was found to primarily exist in the littoral habitat, with molluscs being their predominant food item. The proportion of small fish (Barbus paludinosus, P.) in the big barb diet tended to vary somewhat with size, with the largest fish tending to have the most piscivorous diet. Mercury concentrations in the big barb ranged from 0.01 to 0.94 mg·kg−1, and were positively related with size. Fish transects and stable isotope analyses suggest that there may be two feeding forms of big barb in Lake Awassa, with some larger fish preying upon fish (and accumulating higher mercury concentrations). With the declining Nile tilapia fishery in Lake Awassa, the implication of fishermen focusing on large big barb, with its associated higher Hg burdens, is significant with human health ramifications.
Diel migration patterns of Atlantic salmon smolts with particular reference to the absence of crepuscular migration
Authors: Ibbotson A. T. , Beaumont W. R. C. , Pinder A. , Welton S. , Ladle M.
Published: November 2006

Abstract – The real‐time diel pattern of Atlantic salmon smolt migration was observed for 8 years using automatic resistivity counters verified by video surveillance. A clear dominant nocturnal migration was demonstrated early in the migration period, later becoming increasingly diurnal, until rates became approximately equal at day and night. Migration patterns were related to water temperature, such that when mean daily temperatures were below 12 °C, hourly rates of migration were significantly lower during the day than at night. When daily mean temperatures exceeded 12 °C, there was no significant difference between diurnal and nocturnal migration rates. Migration patterns showed a distinct suppression of migration at dawn and dusk throughout the migration period. It is hypothesised that this behaviour is an active decision and/or an adaptive strategy either to take advantage of increased food in the form of invertebrate drift or to reduce predation risk from actively feeding piscivores or both.
Population structuring in Atlantic salmon (Salmo salar): evidence of genetic influence on the timing of smolt migration in sub‐catchment stocks
Authors: Stewart D. C. , Middlemas S. J. , Youngson A. F.
Published: November 2006

Abstract –  We compared timing of smolt migration for two populations of naturally spawned Atlantic salmon, Salmo salar, originating from an upper catchment (River Tummel) and a lower catchment (River Almond) tributary of the River Tay, Scotland. Smolts from the upper tributary began migration earlier than those from the lower tributary. On both occasions when fry derived from River Isla (lower tributary) stock were transferred to a location in the upper catchment, smolt migration was later than for native fish. Similarly, when fry from Tummel and Isla stocks were stocked in a common, upper catchment location, Isla origin fish migrated at a later date, in both of the two following smolt years. These differences are indicative of a genetic basis for the timing of smolt migration and suggestive of local adaptation. Mounting evidence points towards local genetic adaptation for the timing of expression of behaviours associated with migration. These aspects of variation should be accommodated in management theory and practices.
Helminth parasitism of Galaxias maculatus (Jenyns 1842) in southwestern Australia
Authors: Chapman A. , Hobbs R. P. , Morgan D. L. , Gill H. S.
Published: November 2006

Abstract –  One cestode, Ligula sp. [possibly Ligula intestinalis (L.)], one trematode, Diplostomum sp., and two nematode parasitic worms, Eustrongylides sp. [possibly Eustrongylides gadopsis (Royal Society of South Australia, 64, 340)] and Contracaecum sp. are reported from Galaxias maculatus inhabiting a permanent freshwater lake and two intermittently flowing, saline rivers in southwestern Australia. Worms infecting fish are all larval; the definitive hosts are piscivorous waterfowl. Ligula sp. infected 12% of fish in the lake. Effects of infection include reduced lifespan, significant weight reduction of gonads of males and females and body weight of females. Infection reduces the proportion of males that attain spawning gonad stage more severely than it does in females. The prevalence and intensity of Ligula sp. infection were much less in the rivers. The infection of Pseudogobius olorum (Sauvage 1880) by this cestode is reported for the first time in Western Australia. Trematodes were much more benign in their effect on G. maculatus.
Habitat use of an artificial wetland by the invasive catfish Ameiurus melas
Authors: Cucherousset J. , Paillisson J.‐M. , Carpentier A. , Eybert M.‐C. , Olden J. D.
Published: November 2006

Abstract –  This study examined the distribution and habitat selection of the invasive black bullhead [Ameiurus melas (Rafinesque)] in the ditches and surrounded temporary flooded habitats of an artificial wetland in western France. A multiscale approach was used to quantify patterns of A. melas abundance in relation to physical habitat characteristics in the ditch network. Young‐of‐the‐year (YOY) and adult A. melas largely dominated the local fish assemblage but were highly variable among sites. Although we found evidence for some fine‐scale habitat differences for YOY and adult individuals, the abundance of A. melas was positively and consistently related to the dominance of reed beds. Furthermore, A. melas preferentially used reed beds as opposed to marsh meadows during the flooding period. The results from this study suggest that the invasion of A. melas has been facilitated by the expansion of reed beds associated with the diminution of agricultural pressure in recent decades. This study represents an unusual example where human activities can have had an unexpected effect by facilitating an invasive fish species.
Variation in performance reveals discharge‐related energy costs for foraging Atlantic salmon (Salmo salar) parr
Authors: Kemp P. S. , Gilvear D. J. , Armstrong J. D.
Published: November 2006

Abstract –  The energetic costs associated with foraging and social interaction for Atlantic salmon (Salmo salar) parr was estimated by measuring gross differences in performance (growth and lipid content) during two experimental trials conducted in an artificial river channel, under similar food input at two discharges. The discharges provided velocities within the range commonly experienced by salmon in the wild. Fish growth (second trial) and lipid content (first trial) were the highest at the lower discharge. Fish were less active and used a smaller area of the experimental arena under high flow. These behavioural adjustments are consistent with the reduction of energy costs at high discharge. However, there was no effect of discharge on aggressive behaviour or food intake. Therefore, despite evidence of energy economy in response to high discharge and velocity, the energetic costs of foraging were sufficiently high to cause substantial reduction in performance. In common with the findings of previous studies, dominance status was associated with individual variation in performance and habitat use.
Decoronation – a conservative method to treat ankylosed teeth for preservation of alveolar ridge prior to permanent prosthetic reconstruction: literature review and case presentation
Authors: Cohenca Nestor , Stabholz Ayala
Published: November 2006

Abstract –  Avulsed teeth that are stored extraorally in a dry environment for >60 min generally develop replacement root resorption or ankylosis following their replantation due to the absence of a vital periodontal ligament on their root surface. One negative sequelae of such ankylosis is tooth infra‐positioning and the local arrest of alveolar bone growth. Removal of an ankylosed tooth may be difficult and traumatic leading to esthetic bony ridge deformities and optimal prosthetic treatment interferences. Recently a treatment option for ankylosed teeth named ‘de‐coronation’ gained interest, particularly in pediatric dentistry that concentrated in dental traumatology. This article reviews the up‐to‐date literature that has been published on decoronation with respect to its importance for future prosthetic rehabilitation followed by a case presentation that demonstrates its clinical benefits.
Molecular cloning and characterization of the crustacean hyperglycemic hormone cDNA from Litopenaeus schmitti
Authors: Lugo Juana M. , Morera Yuliet , Rodríguez Tania , Huberman Alberto , Ramos Laida , Estrada Mario P.
Published: November 2006

The crustacean hyperglycemic hormone (CHH) plays an important role in the regulation of hemolymph glucose levels, but it is also involved in other functions such as growth, molting and reproduction. In the present study we describe the first CHH family gene isolated from the Atlantic Ocean shrimp Litopenaeus schmitti. Sequence analysis of the amplified cDNA fragment revealed a high nucleotide sequence identity with other CHHs. Northern blot analysis showed that the isolated CHH mRNA from L. schmitti is present in the eyestalk but not in muscle or stomach. We also investigated the ability of dsRNA to inhibit the CHH function in shrimps in vivo. Injection of CHH dsRNA into the abdominal hemolymh sinuses resulted in undetectable CHH mRNA levels within 24 h and a corresponding decrease in hemolymph glucose levels, suggesting that functional gene silencing had occurred. These findings are the first evidence that dsRNA technique is operative in adult shrimps in vivo.
A designed curved DNA segment that is a remarkable activator of eukaryotic transcription
Authors: Sumida Noriyuki , Nishikawa Jun‐ichi , Kishi Haruka , Amano Miho , Furuya Takayo , Sonobe Haruyuki , Ohyama Takashi
Published: November 2006

To identify artificial DNA segments that can stably express transgenes in the genome of host cells, we built a series of curved DNA segments that mimic a left‐handed superhelical structure. Curved DNA segments of 288 bp (T32) and 180 bp (T20) were able to activate transcription from the herpes simplex virus thymidine kinase (tk) promoter by approximately 150‐fold and 70‐fold, respectively, compared to a control in a transient transfection assay in COS‐7 cells. The T20 segment was also able to activate transcription from the human adenovirus type 2 E1A promoter with an 18‐fold increase in the same assay system, and also activated transcription from the tk promoter on episomes in COS‐7 cells. We also established five HeLa cell lines with genomes containing T20 upstream of the transgene promoter and control cell lines with T20 deleted from the transgene locus. Interestingly, T20 was found to activate transcription in all the stable transformants, irrespective of the locus. This suggests that the T20 segment may allow stable expression of transgenes, which is of importance in many fields, and may also be useful for the construction of nonviral vectors for gene therapy.
The minimal amyloid‐forming fragment of the islet amyloid polypeptide is a glycolipid‐binding domain
Authors: Levy Michal , Garmy Nicolas , Gazit Ehud , Fantini Jacques
Published: November 2006

Several proteins that interact with cell surface glycolipids share a common fold with a solvent‐exposed aromatic residue that stacks onto a sugar ring of the glycolipid (CH–π stacking interaction). Stacking interactions between aromatic residues (π–π stacking) also play a pivotal role in the assembly process, including many cases of amyloid fibril formation. We found a structural similarity between a typical glycolipid‐binding domain (the V3 loop of HIV‐1 gp120) and the minimal amyloid‐forming fragment of the human islet amyloid polypeptide, i.e. the octapeptide core module NFGAILSS. In a monolayer assay at the air–water interface, the NFGAILSS peptide specifically interacted with the glycolipid lactosylceramide. The interaction appears to require an aromatic residue, as NLGAILSS was poorly recognized by lactosylceramide, whereas NYGAILSS behaved like NFGAILSS. In addition, we observed that the full‐length human islet amyloid polypeptide (1–37) did interact with a monolayer of lactosylceramide, and that the glycolipid film significantly affected the aggregation process of the peptide. As glycolipid–V3 interactions are efficiently inhibited by suramin, a polyaromatic compound, we investigated the effects of suramin on amyloid formation by human islet amyloid polypeptide. We found that suramin inhibited amyloid fibril formation at low concentrations, but dramatically stimulated the process at high concentrations. Taken togther, our results indicate that the minimal amyloid‐forming fragment of human islet amyloid polypeptide is a glycolipid‐binding domain, and provide further experimental support for the role of aromatic π–π and CH–π stacking interactions in the molecular control of the amyloidogenesis process.
Impact of alterations near the [NiFe] active site on the function of the H2 sensor from Ralstonia eutropha
Authors: Gebler Antje , Burgdorf Tanja , De Lacey Antonio L. , Rüdiger Olaf , Martinez‐Arias Arturo , Lenz Oliver , Friedrich Bärbel
Published: November 2006

In proteobacteria capable of H2 oxidation under (micro)aerobic conditions, hydrogenase gene expression is often controlled in response to the availability of H2. The H2‐sensing signal transduction pathway consists of a heterodimeric regulatory [NiFe]‐hydrogenase (RH), a histidine protein kinase and a response regulator. To gain insights into the signal transmission from the Ni–Fe active site in the RH to the histidine protein kinase, conserved amino acid residues in the L0 motif near the active site of the RH large subunit of Ralstonia eutropha H16 were exchanged. Replacement of the strictly conserved Glu13 (E13N, E13L) resulted in loss of the regulatory, H2‐oxidizing and D2/H+ exchange activities of the RH. According to EPR and FTIR analysis, these RH derivatives contained fully assembled [NiFe] active sites, and para‐/ortho‐H2 conversion activity showed that these centres were still able to bind H2. This indicates that H2 binding at the active site is not sufficient for the regulatory function of H2 sensors. Replacement of His15, a residue unique in RHs, by Asp restored the consensus of energy‐linked [NiFe]‐hydrogenases. The respective RH mutant protein showed only traces of H2‐oxidizing activity, whereas its D2/H+‐exchange activity and H2‐sensing function were almost unaffected. H2‐dependent signal transduction in this mutant was less sensitive to oxygen than in the wild‐type strain. These results suggest that H2 turnover is not crucial for H2 sensing. It may even be detrimental for the function of the H2 sensor under high O2 concentrations.
Optimality of Hyperbolic Partial Differential Equations With Dynamically Constrained Periodic Boundary Control—A Flow Control Application
Authors: Nguyen Nhan , Ardema Mark
Published: November 2006

This paper is concerned with optimal control of a class of distributed-parameter systems governed by first-order, quasilinear hyperbolic partial differential equations that arise in optimal control problems of many physical systems such as fluids dynamics and elastodynamics. The distributed system is controlled via a forced nonlinear periodic boundary condition that describes a boundary control action. Further, the periodic boundary control is subject to a dynamic constraint imposed by a lumped-parameter system governed by ordinary differential equations that model actuator dynamics. The partial differential equations are thus coupled with the ordinary differential equations via the periodic boundary condition. Optimality of this coupled system is investigated using variational principles to seek an adjoint formulation of the optimal control problem. The results are then applied to solve a feedback control problem of the Mach number in a wind tunnel.
Convex Optimization Approach to Observer-Based Stabilization of Uncertain Linear Systems
Authors: Ibrir Salim
Published: November 2006

New sufficient linear matrix inequality conditions guaranteeing the stability of uncertain linear systems by means of dynamic output feedbacks are presented. It is shown that the search of an observer-based controller for this class of systems is fundamentally decomposed into two main problems: robust stability with a memoryless state feedback and observer design with measured uncertainties. Under the fulfilment of the developed linear matrix inequalities conditions, we show that the observer-based problem is solvable without any need for some equality constraints or iterative computational algorithms. Examples showing the potential of the results are presented.
A Brush-Creeper
Authors: Mak Se-yuen , Wong Siu-ling
Published: November 2006

In this note, we introduce a simple homemade toy called the brush-creeper, which can glide forward with no propellers, limbs, wheels, and seemingly no movement of any kind that can push forward against the ground. The toy arouses pupils' interest and their incentive to ask “Why?” in lessons related to friction.
Simple Experiments for Teaching Air Pressure
Authors: Shamsipour Gholamreza
Published: November 2006

Everyone who teaches physics knows very well that sometimes a simple device or experiment can help to make a concept clear. In this paper, inspired by “The Jumping Pencil”1 by Martin Gardner, I will discuss a simple demonstration device that can be used to start the study of air pressure.
Earplugs and the NRR
Authors: McCall Richard P.
Published: November 2006

Earplugs are sold in most pharmacies. Because I teach at a college of pharmacy, I want my students to understand a particular feature of earplugs called the Noise Reduction Rating, or NRR. The NRR is a rating of the effectiveness of earplugs at decreasing the amount of sound (or noise) entering the ear. Typical values range from 12 dB to 33 dB; the ones I demonstrate in my class have a value of 29 dB.
Modeling the 2004 Indian Ocean Tsunami for Introductory Physics Students
Authors: DiLisi Gregory A. , Rarick Richard A.
Published: November 2006

In this paper we develop materials to address student interest in the Indian Ocean tsunami of December 2004. We discuss the physical characteristics of tsunamis and some of the specific data regarding the 2004 event. Finally, we create an easy-to-make tsunami tank to run simulations in the classroom. The simulations exhibit three dramatic signatures of tsunamis, namely, as a tsunami moves into shallow water its amplitude increases, its wavelength and speed decrease, and its leading edge becomes increasingly steep as if to “break” or “crash.” Using our tsunami tank, these realistic features were easy to observe in the classroom and evoked an enthusiastic response from our students.
Using a Variation Approach To Enhance Physics Learning in a College Classroom
Authors: Linder Cedric , Fraser Duncan
Published: November 2006

This article describes an exploration into improving the process and the outcome of learning in interactive teaching at the first-year university physics level, using what is becoming widely known as the “variation approach to learning.” To explore this approach we chose an area of mechanics that is widely known to pose learning difficulties for students—Newton's third law. Test and interview data provided compelling evidence that explicit use of variation made a difference in student learning outcomes.
Magnetic Spinner
Authors: Ouseph P. J.
Published: November 2006

A science toy sometimes called the “magnetic spinner” is an interesting class demonstration to illustrate the principles of magnetic levitation. It can also be used to demonstrate Faraday's law and a horizontally suspended physical pendulum. The levitated part contains two circular magnets encased in a plastic housing. Each magnet stays above two triangular magnets fixed to the base. The magnetic repulsive force experienced by the circular magnets is independent of their orientation; therefore, the holder of these magnets can be rotated without affecting its stability. The holder with the circular magnets can be oscillated up and down as a horizontally suspended physical pendulum.
A Demonstration of the Work-Kinetic Energy Theorem
Authors: Kamela Martin
Published: November 2006

The work-kinetic energy theorem is one of the fundamental and more subtle concepts students see in their freshman physics course. As it is derived infinitesimally, it is usually used in its integrated form. It is challenging for students to appreciate the work-kinetic energy theorem in the case of a variable force acting over some displacement. Using a motion sensor, a dual range force sensor, and the LabPro computer interface with its Logger Pro software1 and a dynamics track and cart,2 it is possible to demonstrate the concept in a convincing and straightforward manner.
Different Representations of Physics or Hail Poetry! — Thou heaven-born maid, thou gildest e'en the physics teacher's trade! (stolen from W. S. Gilbert)
Authors: Morse Robert
Published: November 2006

Robert Morse, physics teacher at St. Albans School in Washington, D.C., has taught physics in public and private schools for 37 years. His website on Ben Franklin and Electrostatics was recently reviewed in the June 2006 issue of Natural History Magazine. A previous foray into poetry, “The Pool Table Physics Lab Rap,” is one of the pieces on the Physics Pholk Songs CD, part of the Activity-Based Physics project.
Variable Impact of Combining Fatal and Nonfatal End Points in Heart Failure Trials
Authors: Skali Hicham , Pfeffer Marc A. , Lubsen Jacobus , Solomon Scott D.
Published: November 2006

Randomized clinical trials (RCTs) are a cornerstone of evidence-based medicine. Their design, implementation, and interpretation are sometimes subject to flaws and errors. To achieve statistical significance and economically feasible RCTs, the use of composite end points in heart failure (HF) trials has become more common. We analyzed the incremental value of combining HF hospitalizations with all-cause mortality in trials of chronic HF that enrolled >1000 placebo patients and had a mean follow-up >9 months. We tested the assumption that, compared with mortality, combining HF hospitalization with all-cause death would yield a consistently predictable increase in event rate across HF RCTs. Average placebo arm duration of follow-up was determined, and standardized placebo event rates per 100 patient-years were estimated. Twelve major HF RCTs were included in this analysis. There was a substantial relative increase in the event rate ranging from 64% to 134% when a composite end point was used. This increase was not related to disease severity as described by annual mortality rate. The relative contribution of combining HF hospitalization with all-cause mortality was, however, influenced by the duration of the trial. Combining HF hospitalization with all-cause mortality increases the overall event rate in HF clinical trials; the relative increase varies widely and is unrelated to disease severity. Longer-duration trials have a more predictable increase in events than short RCTs. Trial duration must be considered when composite end points are used during the design and interpretation of HF RCTs.
Can Isopycnal Mixing Control the Stability of the Thermohaline Circulation in Ocean Climate Models?
Authors: Sijp Willem P. , Bates Michael , England Matthew H.
Published: November 2006

Convective overturning arising from static instability during winter is thought to play a crucial role in the formation of North Atlantic Deep Water (NADW). In ocean general circulation models (OGCMs), a strong reduction in convective penetration depth arises when horizontal diffusion (HD) is replaced by Gent and McWilliams (GM) mixing to model the effect of mesoscale eddies on tracer advection. In areas of sinking, the role of vertical tracer transport due to convection is largely replaced by the vertical component of isopycnal diffusion along sloping isopycnals. Here, the effect of this change in tracer transport physics on the stability of NADW formation under freshwater (FW) perturbations of the North Atlantic (NA) in a coupled model is examined. It is found that there is a significantly increased stability of NADW to FW input when GM is used in spite of GM experiments exhibiting consistently weaker NADW formation rates in unperturbed steady states. It is also found that there is a significant increase in NADW stability upon the introduction of isopycnal diffusion in the absence of GM. This indicates that isopycnal diffusion of tracer rather than isopycnal thickness diffusion is responsible for the increased NADW stability observed in the GM run. This result is robust with respect to the choice of isopycnal diffusion coefficient. Also, the NADW behavior in the isopycnal run, which includes a fixed background horizontal diffusivity, demonstrates that HD is not responsible in itself for reducing NADW stability when simple horizontal diffusion is used. Our results suggest that care should be taken when interpreting the results of coarse grid models with regard to NADW sensitivity to FW anomalies, regardless of the choice of mixing scheme.
Projection and Analysis of Extreme Wave Climate
Authors: Caires Sofia , Swail Val R. , Wang Xiaolan L.
Published: November 2006

The nonhomogeneous Poisson process is used to model extreme values of the 40-yr ECMWF Re-Analysis (ERA-40) significant wave height. The parameters of the model are expressed as functions of the seasonal mean sea level pressure anomaly and seasonal squared sea level pressure gradient index. Using projections of the sea level pressure under three different forcing scenarios by the Canadian coupled climate model, projections of the parameters of the nonhomogeneous Poisson process are made, trends in these projections are determined, return-value estimates of significant wave height up to the end of the twenty-first century are projected, and their uncertainties are assessed. The uncertainty of estimates associated with the nonhomogeneous Poisson process estimates is studied and compared with the homologous estimates obtained using a nonstationary generalized extreme value model.
Transition between Suppressed and Active Phases of Intraseasonal Oscillations in the Indo-Pacific Warm Pool
Authors: Agudelo P. A. , Curry J. A. , Hoyos C. D. , Webster P. J.
Published: November 2006

Intraseasonal oscillations (ISOs) are important large-amplitude and large-scale elements of the tropical Indo-Pacific climate with time scales in the 20–60-day period range, during which time they modulate higher-frequency tropical weather. Despite their importance, the ISO is poorly simulated and predicted by numerical models. A joint diagnostic and modeling study of the ISO is conducted, concentrating on the period between the suppressed and active (referred to as the “transition”) period that is hypothesized to be the defining stage for the development of the intraseasonal mode and the component that is most poorly simulated.

The diagnostic study uses data from the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE). It is found that during the transition period, the ocean and the atmosphere undergo gradual but large-scale and high-amplitude changes, especially the moistening of the lower troposphere caused jointly by the anomalously warm sea surface temperature arising from minimal cloud and low winds during the suppressed phase and the large-scale subsidence that inhibits the formation of locally deep convection. Using a cloud classification scheme based on microwave and infrared satellite data, it is observed that midtop (cloud with a top in the middle troposphere) nonprecipitating clouds are a direct response of the low-level moisture buildup.

To investigate the sensitivity of ISO simulations to the transitional phase, the European Centre for Medium-Range Weather Forecasts (ECMWF) coupled ocean–atmosphere climate model is used. The ECMWF was run serially in predictive ensemble mode (five members) for 30-day periods starting from 1 December 1992 to 30 January 1993, encompassing the ISO occurring in late December. Predictability of the active convective period of the ISO is poor when initialized before the transitional phases of the ISO. However, when initialized with the correct lower-tropospheric moisture field, predictability increases substantially, although the model convective parameterization appears to trigger convection too quickly without allowing an adequate buildup of convective available potential energy during the transition period.
Cloud Properties and Their Seasonal and Diurnal Variability from TOVS Path-B
Authors: Stubenrauch C. J. , Chédin A. , Rädel G. , Scott N. A. , Serrar S.
Published: November 2006

Eight years of cloud properties retrieved from Television Infrared Observation Satellite-N (TIROS-N) Observational Vertical Sounder (TOVS) observations aboard the NOAA polar orbiting satellites are presented. The relatively high spectral resolution of these instruments in the infrared allows especially reliable cirrus identification day and night. This dataset therefore provides complementary information to the International Satellite Cloud Climatology Project (ISCCP). According to this dataset, cirrus clouds cover about 27% of the earth and 45% of the Tropics, whereas ISCCP reports 19% and 25%, respectively. Both global datasets agree within 5% on the amount of single-layer low clouds, at 30%. From 1987 to 1995, global cloud amounts remained stable to within 2%. The seasonal cycle of cloud amount is in general stronger than its diurnal cycle and it is stronger than the one of effective cloud amount, the latter the relevant variable for radiative transfer. Maximum effective low cloud amount over ocean occurs in winter in SH subtropics in the early morning hours and in NH midlatitudes without diurnal cycle. Over land in winter the maximum is in the early afternoon, accompanied in the midlatitudes by thin cirrus. Over tropical land and in the other regions in summer, the maximum of mesoscale high opaque clouds occurs in the evening. Cirrus also increases during the afternoon and persists during night and early morning. The maximum of thin cirrus is in the early afternoon, then decreases slowly while cirrus and high opaque clouds increase. TOVS extends information of ISCCP during night, indicating that high cloudiness, increasing during the afternoon, persists longer during night in the Tropics and subtropics than in midlatitudes. A comparison of seasonal and diurnal cycle of high cloud amount between South America, Africa, and Indonesia during boreal winter has shown strong similarities between the two land regions, whereas the Indonesian islands show a seasonal and diurnal behavior strongly influenced by the surrounding ocean. Deeper precipitation systems over Africa than over South America do not seem to be directly reflected in the horizontal coverage and mesoscale effective emissivity of high clouds.