bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing observations and process‐based simulations of biosphere‐atmosphere exchanges on multiple timescales
Authors: Mahecha M. D. , Reichstein M. , Jung M. , Seneviratne S. I. , Zaehle S. , Beer C. , Braakhekke M. C. , Carvalhais N. , Lange H. , Le Maire G. , Moors E.
Published: April 2010

Terrestrial biosphere models are indispensable tools for analyzing the biosphere‐atmosphere exchange of carbon and water. Evaluation of these models using site level observations scrutinizes our current understanding of biospheric responses to meteorological variables. Here we propose a novel model‐data comparison strategy considering that CO2 and H2O exchanges fluctuate on a wide range of timescales. Decomposing simulated and observed time series into subsignals allows to quantify model performance as a function of frequency, and to localize model‐data disagreement in time. This approach is illustrated using site level predictions from two models of different complexity, Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and Lund‐Potsdam‐Jena (LPJ), at four eddy covariance towers in different climates. Frequency‐dependent errors reveal substantial model‐data disagreement in seasonal‐annual and high‐frequency net CO2 fluxes. By localizing these errors in time we can trace these back, for example, to overestimations of seasonal‐annual periodicities of ecosystem respiration during spring greenup and autumn in both models. In the same frequencies, systematic misrepresentations of CO2 uptake severely affect the performance of LPJ, which is a consequence of the parsimonious representation of phenology. ORCHIDEE shows pronounced model‐data disagreements in the high‐frequency fluctuations of evapotranspiration across the four sites. We highlight the advantages that our novel methodology offers for a rigorous model evaluation compared to classical model evaluation approaches. We propose that ongoing model development will benefit from considering model‐data (dis)agreements in the time‐frequency domain.
Pc5 wave power in the quiet‐time plasmasphere and trough: CRRES observations
Authors: Hartinger Michael , Moldwin Mark B. , Angelopoulos Vassilis , Takahashi Kazue , Singer Howard J. , Anderson Roger R. , Nishimura Yukitoshi , Wygant John R.
Published: April 2010

The Combined Release and Radiation Effects Satellite (CRRES) mission provides an opportunity to study the distribution of MHD wave power in the inner magnetosphere both inside the high‐density plasmasphere and in the low‐density trough. We present a statistical survey of Pc5 power using CRRES magnetic field, electric field, and plasma wave data separated into plasmasphere and trough intervals. Using a database of plasmapause crossings, we examined differences in power spectral density between the plasmasphere and trough regions. These differences were typically a factor of 3 or 4 but could be as much as an order of magnitude and could be seen in both electric and magnetic field data. Our study shows that determining the plasmapause location is important for understanding and modeling the MHD wave environment in the Pc5 frequency band.
Acceleration of scattered solar wind protons at the polar terminator of the Moon: Results from Chang'E‐1/SWIDs
Authors: Wang X.‐D. , Bian W. , Wang J.‐S. , Liu J.‐J. , Zou Y.‐L. , Zhang H.‐B. , Lü C. , Liu J.‐Z. , Zuo W. , Su Y. , Wen W.‐B. , Wang M. , Ouyang Z.‐Y. , Li C.‐L.
Published: April 2010

We report accelerated particles observed by Solar Wind Ion Detectors (SWIDs) on Chang'E‐1 spacecraft close to terminator regions of the Moon. As the spacecraft crosses the terminator, a stream of ions with energy of ∼200eV/q are detected. As the spacecraft moves to the anti‐subsolar point of the Moon, the energy of these ions increase by 600 ∼ 1500eV. This phenomenon occurs at north/south pole when IMF By component is dominant and negative/positive. It is proposed these particles are scattered solar wind protons, accelerated by the convection electric field of the solar wind and E × B drift in the ambipolar electric field at the flank of the lunar wake. This mechanism allows a new portion of solar wind protons to enter the central lunar wake, and provides a possibility to study the property of proton scattering at the dayside of the Moon.
Complex array of endobionts in Petalomonas sphagnophila, a large heterotrophic euglenid protist from Sphagnum-dominated peatlands
Authors: Kim Eunsoo , Park Jong Soo , Simpson Alastair G B , Matsunaga Shigeru , Watanabe Masakatsu , Murakami Akio , Sommerfeld Katrin , Onodera Naoko T , Archibald John M
Published: April 2010

Petalomonas sphagnophila is a poorly studied plastid-lacking euglenid flagellate living in Sphagnum-dominated peatlands. Here we present a broad-ranging microscopic, molecular and microspectrophotometric analysis of uncultured P. sphagnophila collected from four field locations in Nova Scotia, Canada. Consistent with its morphological characteristics, 18S ribosomal DNA (rDNA) phylogenies indicate that P. sphagnophila is specifically related to Petalomonas cantuscygni, the only other Petalomonas species sequenced to date. One of the peculiar characteristics of P. sphagnophila is the presence of several green-pigmented particles ∼5 μm in diameter in its cytoplasm, which a previously published study suggested to be cyanobacterial endosymbionts. New data presented here, however, suggest that the green intracellular body may not be a cyanobacterium but rather an uncharacterized prokaryote yet to be identified by molecular sequencing. 16S rDNA library sequencing and fluorescence in situ hybridizations show that P. sphagnophila also harbors several other endobionts, including bacteria that represent five novel genus-level groups (one firmicute and four different proteobacteria). 16S rDNA phylogenies suggest that three of these endobionts are related to obligate intracellular bacteria such as Rickettsiales and Coxiella, while the others are related to the Daphnia pathogen Spirobacillus cienkowskii or belong to the Thermoactinomycetaceae. TEM, 16S rDNA library sequencing and a battery of PCR experiments show that the presence of the five P. sphagnophila endobionts varies markedly among the four geographic collections and even among individuals collected from the same location but at different time points. Our study adds significantly to the growing evidence for complex and dynamic protist–bacterial associations in nature.
A Randomized Trial of Lifestyle Modification and Taranabant for Maintaining Weight Loss Achieved With a Low‐Calorie Diet
Authors: Wadden Thomas A. , Fujioka Ken , Toubro Soren , Gantz Ira , Erondu Ngozi E. , Chen Menghui , Suryawanshi Shailaja , Carofano Wendy , Johnson‐Levonas Amy O. , Shapiro Deborah R. , Kaufman Keith D. , Heymsfield Steven B. , Amatruda John M.
Published: April 2010

Improving the maintenance of weight loss remains a critical challenge for obesity researchers. The present 1‐year, randomized, placebo‐controlled trial evaluated the safety and efficacy of weight maintenance counseling combined with either placebo or the cannabinoid‐1 receptor inverse agonist, taranabant, for sustaining prior weight loss achieved on a low‐calorie diet (LCD). Seven hundred eighty‐four individuals who had lost ≥6% of body weight during six initial weeks of treatment with an 800 kcal/day liquid LCD were randomly assigned to placebo or once‐daily taranabant in doses of 0.5, 1, or 2 mg. All participants were provided monthly, on‐site behavioral weight maintenance counseling, as well as monthly phone calls. The primary end point was change in body weight from randomization to week 52. The randomized participants lost an average of 9.6 kg (9.5% of initial weight) during the 6‐week LCD. The model‐adjusted mean change in body weight during the subsequent 1 year was +1.7 kg for placebo, compared with −0.1, −0.6, and −1.2 kg for the taranabant 0.5, 1, and 2 mg doses, respectively (all P values ≤0.007 vs. placebo). The incidences of psychiatric‐related adverse events, including irritability, were higher for taranabant 1 and 2 mg vs. placebo (P ≤ 0.038). In addition to reporting data on the safety and efficacy of taranabant, this study provides a method for studying the combination of lifestyle modification and pharmacotherapy for weight maintenance after diet‐induced weight loss.
Altered Intramuscular Lipid Metabolism Relates to Diminished Insulin Action in Men, but Not Women, in Progression to Diabetes
Authors: Perreault Leigh , Bergman Bryan C. , Hunerdosse Devon M. , Eckel Robert H.
Published: April 2010

Whether sex differences in intramuscular triglyceride (IMTG) metabolism underlie sex differences in the progression to diabetes are unknown. Therefore, the current study examined IMTG concentration and fractional synthesis rate (FSR) in obese men and women with normal glucose tolerance (NGT) vs. those with prediabetes (PD). PD (n = 13 men and 7 women) and NGT (n = 7 men and 12 women) groups were matched for age and anthropometry. Insulin action was quantified using a hyperinsulinemic‐euglycemic clamp with infusion of [6,6−2H2]‐glucose. IMTG concentration was measured by gas chromatography/mass spectrometry (GC/MS) and FSR by GC/combustion isotope ratio MS (C‐IRMS), from muscle biopsies taken after infusion of [U−13C]palmitate during 4 h of rest. In PD men, the metabolic clearance rate (MCR) of glucose was lower during the clamp (4.71 ± 0.77 vs. 8.62 ± 1.26 ml/kg fat‐free mass (FFM)/min, P = 0.04; with a trend for lower glucose rate of disappearance (Rd), P = 0.07), in addition to higher IMTG concentration (41.2 ± 5.0 vs. 21.2 ± 3.4 µg/mg dry weight, P ≤ 0.01), lower FSR (0.21 ± 0.03 vs. 0.42 ± 0.06 %/h, P ≤ 0.01), and lower oxidative capacity (P = 0.03) compared to NGT men. In contrast, no difference in Rd, IMTG concentration, or FSR was seen in PD vs. NGT women. Surprisingly, glucose Rd during the clamp was not different between NGT men and women (P = 0.25) despite IMTG concentration being higher (42.6 ± 6.1 vs. 21.2 ± 3.4 µg/mg dry weight, P = 0.03) and FSR being lower (0.23 ± 0.04 vs. 0.42 ± 0.06 %/h, P = 0.02) in women. Alterations in IMTG metabolism relate to diminished insulin action in men, but not women, in the progression toward diabetes.
Insulin Resistance is the Best Predictor of the Metabolic Syndrome in Subjects With a First‐Degree Relative With Type 2 Diabetes
Authors: Utzschneider Kristina M. , Van de Lagemaat Anne , Faulenbach Mirjam V. , Goedecke Julia H. , Carr Darcy B. , Boyko Edward J. , Fujimoto Wilfred Y. , Kahn Steven E.
Published: April 2010

Although obesity is associated with insulin resistance and the metabolic syndrome (MetS), some obese individuals are metabolically healthy. Conversely, some lean individuals are insulin resistant (IR) and at increased cardiometabolic risk. To determine the relative importance of insulin sensitivity, BMI and waist circumference (WC) in predicting MetS, we studied these two extreme groups in a high‐risk population. One thousand seven hundred and sixty six subjects with a first‐degree relative with type 2 diabetes were stratified by BMI and homeostasis model assessment of insulin resistance (HOMAIR) into groups. IR groups had higher triglycerides, fasting glucose, and more diabetes than their BMI‐group insulin sensitive (IS) counterparts. Within both IS and IR groups, obesity was associated with higher HOMAIR and diastolic blood pressure (BP), but no difference in other metabolic variables. MetS (Adult Treatment Panel III (ATPIII)) prevalence was higher in IR groups (P < 0.001) and more subjects met each MetS criterion (P < 0.001). Within each BMI category, HOMAIR independently predicted MetS (P < 0.001) whereas WC did not. Within IS and IR groups, age and WC, but not BMI, were independent determinants of MetS (P < 0.001). WC was a less meaningful predictor of MetS at higher values of HOMAIR. HOMAIR was a better predictor of MetS than WC or BMI (receiver operating characteristic (ROC) area under the curve 0.76 vs. 0.65 vs. 0.59, P < 0.001). In conclusion, insulin sensitivity rather than obesity is the major predictor of MetS and is better than WC at identifying obese individuals with a healthier metabolic profile. Further, as many lean individuals with a first‐degree relative with type 2 diabetes are IR and metabolically unhealthy, they may all benefit from metabolic testing.
Appetite‐Regulating Hormone Changes in Patients With Craniopharyngioma
Authors: Roth Christian L. , Gebhardt Ursel , Müller Hermann L.
Published: April 2010

Patients with craniopharyngioma (CP), an embryological tumor located in the hypothalamic and/or pituitary region, often suffer from uncontrolled eating and severe obesity. We aimed to compare peripherally secreted hormones involved in controlling food intake in normal weight and obese children and adolescents with CP vs. controls. Plasma insulin, glucose, total ghrelin, and peptide‐YY (PYY) levels were assessed under fasting conditions as well as 60 min after liquid mixed meal in four groups: Normal weight (n = 12) and obese (n = 15) CP patients, and 12 normal weight and 15 obese otherwise healthy BMI‐, gender‐ and age‐matched controls. Homeostasis model assessment of insulin resistance (HOMAIR), as well as quantitative insulin sensitivity check index (QUICKI) were calculated. Obese CP subjects had significantly higher HOMAIR, higher baseline and postmeal insulin but lower ghrelin levels, weaker postmeal changes for PYY, and lower QUICKI compared to obese controls. QUICKI data from all CP patients correlated positively with ghrelin and PYY % postmeal changes (ghrelin: r = 0.38, P = 0.023; PYY r = 0.40, P = 0.017) and negatively with standard deviation score‐BMI (SDS‐BMI: r = −0.49, P = 0.002). Tumor growth of 87% obese and 58% of normal weight CP patients affected the hypothalamic area which was associated with higher SDS‐BMI and weaker % postmeal ghrelin changes (P = 0.014) compared to CP patients without hypothalamic tumor involvement. Blunted postmeal ghrelin and PYY responses in obese CP subjects are likely due to their higher degree of insulin resistance and lower insulin sensitivity compared to matched obese controls. Thus, insulin resistance in CP patients seems to affect eating behavior by affecting meal responses of gut peptides.
Reversal of Inflammation‐Induced Impairment of Glucose Uptake in Adipocytes by Direct Effect of CB1 Antagonism on Adipose Tissue Macrophages
Authors: Miranville Alexandra , Herling Andreas W. , Biemer‐Daub Gabriele , Voss Marc D.
Published: April 2010

Macrophage infiltration into adipose tissue (AT‐MP) is thought to induce insulin resistance and diabetes in obesity. Here, we investigated the effect of the antiobesity drug SR141716 (a CB1 antagonist) on macrophage‐mediated inhibition of insulin signaling in adipocytes. THP1 macrophages (THP1) were stimulated in vitro with lipopolysaccharide (LPS) and SR141716 or vehicle. The resulting conditioned medium (CM) was analyzed and incubated on human adipocytes. CM from LPS‐stimulated THP1 inhibited insulin‐induced AKT phosphorylation in adipocytes, in contrast to CM from nonactivated THP1. Moreover, it contained higher concentrations of tumor necrosis factor‐α (TNFα) and lower levels of the anti‐inflammatory cytokine IL‐10. SR141716 reduced TNFα production and increased IL‐10 secretion, resulting in a rescue of insulin signaling in adipocytes. To confirm these findings in vivo, AT‐MP CM from cafeteria diet‐fed or Zucker diabetic fatty (ZDF) rats that had received SR141716 for 3 weeks were isolated, analyzed, and incubated with adipocytes. Cafeteria diet induced macrophage‐mediated inhibition of insulin signaling in adipocytes. Interestingly, SR141716 rescued insulin‐induced glucose uptake in adipocytes. Finally, AT‐MP CM from obese ZDF rats inhibited insulin‐stimulated glucose uptake in adipocytes in contrast to AT‐MP CM from lean ZDF rats. After treatment with SR141716, AT‐MP CM rescued insulin‐induced glucose uptake in adipocytes. In summary, our data indicate that CB1 receptor antagonism in macrophages modified their cytokine production and improved the insulin responsiveness of adipocytes that had been incubated with macrophage CM. Thus, SR141716 ameliorated adipose tissue insulin resistance by direct action on AT‐MP demonstrating a novel peripheral mode of action of CB1 antagonism.
Association of FTO Gene Variants With Adiposity in African‐American Adolescents
Authors: Bollepalli Sureka , Dolan Lawrence M. , Deka Ranjan , Martin Lisa J.
Published: April 2010

The prevalence of obesity continues to increase significantly, with the largest rise in the African‐American adolescents. Genetic contributions to obesity are being identified with the advent of genome‐wide association studies (GWAS). Specifically, variants of the fat mass and obesity associated (FTO) gene have been associated with obesity in populations of European descent. The studies in African Americans have been inconclusive. To further evaluate the association of the FTO gene and adiposity in African Americans, we genotyped 47 single‐nucleotide polymorphisms (SNPs), including seven SNPs previously reported to be significant in the literature in a cohort consisting of 561 non‐Hispanic white and 497 African‐American individuals. Analysis of our data showed 17 SNPs to be associated with BMI Z‐score (BMI‐Z) in our study population. The strongest association was found in the African Americans. The most significant SNP was rs8057044, which was associated with BMI‐Z in the African Americans (P = 0.00054). SNP rs9939609 was found to be significant in the non‐Hispanic white population (P = 0.028). Our data confirm the association between FTO and adiposity suggesting that FTO is a childhood obesity susceptibility gene. Our data also identify a novel SNP of the FTO gene (rs8057044) that is associated with measures of adiposity in the African‐American population.
Pre‐ to Postoperative Physical Activity Changes in Bariatric Surgery Patients: Self Report vs. Objective Measures
Authors: Bond Dale S. , Jakicic John M. , Unick Jessica L. , Vithiananthan Sivamainthan , Pohl Dieter , Roye G. Dean , Ryder Beth A. , Sax Harry C. , Wing Rena R.
Published: April 2010

Bariatric surgery patients report significant pre‐ to postoperative increases in physical activity (PA). However, it is unclear whether objective measures would corroborate these changes. The present study compared self‐reported and accelerometer‐based estimates of changes in moderate‐to‐vigorous intensity PA (MVPA) from pre‐ (pre‐op) to 6 months postsurgery (post‐op). Twenty bariatric surgery (65% laparoscopic‐adjustable gastric banding, 35% gastric bypass) patients (46.2 ± 9.8 years, 88% female, pre‐op BMI = 50.8 ± 9.7 kg/m2) wore RT3 accelerometers as an objective measure of MVPA and completed the Paffenbarger Physical Activity Questionnaire (PPAQ) as a subjective measure before and 6 months after bariatric surgery. Time (min/week) spent in MVPA was calculated for the PPAQ and RT3 (≥1‐min and ≥10‐min bouts) at pre‐op and post‐op. Self‐reported MVPA increased fivefold from pre‐op to post‐op (44.6 ± 80.8 to 212.3 ± 212.4 min/week; P < 0.005). By contrast, the RT3 showed nonsignificant decreases in MVPA for both ≥1‐min (186.0 ± 169.0 to 151.2 ± 118.3 min/week) and ≥10‐min (41.3 ± 109.3 to 39.8 ± 71.3 min/week) bouts. At pre‐op, the percentage of participants who accumulated ≥150‐min/week of MVPA in bouts ≥10‐min according to the PPAQ and RT3 was identical (10%). However, at post‐op, 55% of participants reported compliance with the recommendation compared to 5% based on RT3 measurement (P = 0.002). Objectively‐measured changes in MVPA from pre‐op to 6 months post‐op appear to be much smaller than self‐reported changes. Further research involving larger samples is needed to confirm these findings and to determine whether self‐report and objective PA measures are differentially associated with surgical weight loss outcomes.
Nanotechnologies in Food
Authors: Arnout Fisher , Frewer Lynn , Bennett David , Morris Vic , Smolander Maria , Kampers Frans , Bouwmeester Hans , Gergely Anna , Bowman Diana , Tran Lang ,   Royal Society of Chemistry
Published: April 2010

Recent developments in the field of nanotechnology have paved the way for lots of innovation in a number of industrial and consumer sectors, including food and food packaging. Whilst nanofood sector is a relatively new emergent, it is widely expected to grow rapidly in the future. A number of nano-sized additives and supplements for food and healthfood products, and nanotechnology derived food packaging materials, are already available in some countries, and their number is expected to increase in the coming years. Whilst such developments offer enormous benefits to the food sector, they have also raised a number of issues in relation to consumer safety, environmental impacts, and ethical, policy and regulatory aspects. Despite these rapid developments in nanotechnology applications for the food sector, only a few reports and articles are currently available that provide an account of the new developments and the current size of market for nanotechnology products and applications. These also do not provide a critical evaluation of the broader aspects of the technology, such as issues around safety of the products to consumers and the environment, and adequacy of the existing regulatory controls. This book provides a source of much needed and up-to-date information on the products and applications of nanotechnology for the food sector - for scientists, regulators, and consumers alike. It also gives an independent, balanced, and impartial view of the potential benefits as well as risks that nanotechnology applications may bring to the food sector. Whilst providing an overview of the state-of-the-art and foreseeable applications to highlight opportunities for innovation, the book also discusses areas of uncertainty in relation to public perception of the new technological developments, and potential implications for consumer safety and current regulatory controls. The book also discusses the likely public perceptions of nanotechnologies in the light of past technological developments in the food sector, and how the new technology will possibly be regulated under the existing regulatory frameworks.
Nanotechnologies in the Food Arena: New Opportunities, New Questions, New Concerns
Authors: Chaudhry Qasim , Watkins Richard , Castle Laurence
Published: April 2010

This first chapter sets the scene for the subsequent chapters on individual application areas of nanotechnologies that are written by acknowledged experts in their respective fields. It describes and defines the relevant materials, products, and applications of nanotechnologies, and highlights the distinctive chemical and physical attributes that make them so attractive for applications in the food sector. The chapter presents a summary of the current and projected applications of nanotechnologies, and opens up a discussion on the different issues that have emanated from such applications in the food sector. It emphasises that public perception and ultimate acceptance or rejection of nanotech food products hinges on what benefits they bring, and to whom, and also on whether they may pose a potential risk to the consumer. In this regard, it also raises the question whether the novel chemical and physical attributes of some nanomaterials can give rise to some hitherto unrecognised health hazard. The chapter then raises questions on the applicability of current risk assessment procedures and the adequacy of regulatory frameworks for new products.
Public Perceptions of Nanotechnologies: Lessons from GM Foods
Authors: Bennet David
Published: April 2010

This chapter assesses how public attitudes to new food technologies and the key ‘actors' in the debate (scientists, consumer groups, industry, the media and environmental groups) have changed over recent years, and how these changes may impact on our acceptance of nanotechnologies in food. It argues that, for a new technology, like nanotechnologies, the public must provide, in effect, a ‘licence to produce’ before the new products can come to the market and succeed. It highlights that despite the fact that the current level of public knowledge of the risks and benefits of nanotechnology is very low, more people were optimistic about nanotechnology in 2005 than in 2002. The chapter also points to one of the hard-learned lessons from the GM debate that the vast majority of European people are not really interested in science unless they have a personal need. Therefore an informed engagement of public on nano-foods is likely to be challenging. It also suggests ways to move the nano(bio)technology debate forward, and stresses the need to encourage and support scientists to explain their science and its significance for the general good.
Natural Food Nanostructures
Authors: Morris Victor J.
Published: April 2010

The development in the early 1980s of new nanoscience tools such as probe microscopy and, in particular, atomic force microscopy, has provided new methods for probing food structures at the molecular level, under near native conditions. The development and use of microscopic techniques in food science has always led to new scientific understanding of food structure and has spawned new technological applications. The availability of probe microscopes has allowed the investigation and solution of previously intractable problems in food science. Such understanding provides a basis for selecting or manipulating the natural nanostructures formed by food molecules, but through rational, rather than empirical selection of new raw materials, or the improvement and new design of food materials through conventional processing methods. Nanoscience thus enables the improvement of natural nanostructures, through the use of standard and accepted selection and processing methods. This approach is illustrated through studies on starch and protein-stabilised foams and emulsions. It is shown how improved understanding of food structure at the molecular scale can be used to select, modify, or design food structures to meet current challenges in regard to nutrition and health. The use of nanoscience to enable the selection of new improved raw materials, and to modify conventional processing methods, provides a basis for designing new functional foods. The status of such products is discussed in the light of the wider debate on nanotechnologies and food.
Nanotechnology Applications for Food Ingredients, Additives and Supplements
Authors: Chaudhry Qasim , Groves Kathy
Published: April 2010

This chapter presents a detailed account of the known and under-development applications of nanotechnologies for food ingredients, additives and supplements. It discusses the role of nanostructures and nanomaterials in developing new food textures and tastes. Because of high surface area, a relatively small amount of a nano-sized additive may be sufficient to deliver a much greater perception of a taste or flavour. This may enable a reduction in the amount of salt, fat, and other additives in food, such as artificial colours, flavouring agents, preservatives etc, whilst still offering improved aesthetic, nutritional, and health benefits. Other application areas involve the use of nanomaterials for antimicrobial properties, and nano-sized supplements that are claimed for enhanced uptake and bioavailability in the body. The chapter also discusses the likely translocation, uptake and digestion of nanomaterials in the gastrointestinal tract, and suggests that the use of 'soft’ (soluble, digestible, non-biopersistent) nanomaterials, such as food nanostructures and nano-emulsions, is likely to spearhead the way for nanotechnology innovations in the (health)food sectors.
Nanotechnologies in Food Packaging
Authors: Smolander Maria , Chaudhry Qasim
Published: April 2010

The main function of food packaging is to protect and preserve the food, to maintain its quality and safety, and to reduce food waste. Other desirable attributes have come to the fore recently including packaging that is sustainable with a low environmental footprint, is “active” and/or is “intelligent.” As materials and applications of nanotechnologies can help meet these requirements, they are rapidly becoming a commercial reality in the area of food packaging. Example applications include the enhancement of mechanical properties to allow development of further light-weight materials, and using nanocomposites or nanocoatings to improve barrier properties. An especially interesting area of application is using nanotechnology products to increase the performance of some biobased and biodegradable materials so that they can be used for a wider range of food applications and not only dry foods. There are also a number of products under development for active packaging – which can release or absorb chemicals – or as intelligent (smart) packaging materials that incorporate nano-sensors. Consequently, nanotechnology products and applications could revolutionise some areas of the food packaging sector, providing innovative, sustainable, strong, lightweight and active and intelligent materials. Market uptake will however be impeded by any uncertainties on consumer and environmental safety. Based on theoretical considerations, and the results of limited testing that has been carried out so far, the expectation is that due to the fixed or embedded nature of nanomaterials in plastics, they are not likely to pose a significant risk to the consumer. However, further research addressing the safety issues of nanotechnologies is needed.
Engineered Nanoparticles and Food: An Assessment of Exposure and Hazard
Authors: Tran Lang , Chaudhry Qasim
Published: April 2010

This chapter looks at the toxicological hazard and exposure issues emanating from the use of engineered nanomaterials in food. A number of concerns have been raised over the safety of insoluble and biopersistent nanoparticles to human health and the environment. In this regard, there is emerging evidence in literature to suggest that, due to extremely small size, free nanoparticles are capable of penetrating biological membranes. This adds a new dimension to particle toxicology as nanoparticles may reach those targets in the body that are protected by barriers against the entry of larger particulate materials. However, much of the currently available toxicological evidence relates to inhalation exposure and studies on oral intake of engineered nanoparticles have only just started to emerge. Many of the reported effects have been derived from in vitro assays, or at very high doses. The current unavailability of validated methodologies for detection and characterisation of nanoparticles in complex food matrices poses further difficulties in the assessment of exposure to nanoparticles via consumption of nanofoods. The chapter suggests possible strategies for toxicological evaluation of nanoparticles, and stresses the need for tests that are carried out over prolonged exposures and are followed by histopathological investigations on multiple organs.
Small Ingredients in a Big Picture: Regulatory Perspectives on Nanotechnologies in Foods and Food Contact Materials
Authors: Gergely Anna , Bowman Diana , Chaudhry Qasim
Published: April 2010

The convergence of nanotechnologies with the food and food processing sector will further revolutionise the agri-food sector. Yet despite the growing concern of the potential risks posed by some engineered nanoparticles, and the adequacy of existing legislative frameworks to protect human health and safety, a number of foods and food packaging materials have already reached the supermarket shelves in some countries. In light of these concerns, this chapter provides an in-depth examination of the strengths and weaknesses of the food safety regulatory frameworks in the European Union and the United States for managing potential risks posed by nanotechnologies in food and food packaging. In acknowledging the delicate balance involved in promoting technological innovation while simultaneously taking reasonable precautions to protect the public, the chapter concludes by articulating a range of mechanisms that could be adopted to assist governments in achieving this fine balance in relation to food safety.
An Outline Framework for the Governance for Risks of Nanotechnologies in Food
Authors: Möller Martin , Eberle Ulrike , Hermann Andreas , Som Claudia
Published: April 2010

Despite some negative consumer perception of nanotechnologies for food applications, certain food and food packaging applications have a potential for the future. Many questions have, however, arisen in regard to the possible toxicological impacts of nanomaterials on human health and the environment. Thus, an appropriate risk governance framework for the use of engineered nanomaterials in food and food packaging is needed. Such a framework should facilitate the realisation of the new technologies in a sustainable manner, while at the same time avoid potential risks to consumers and the environment. This chapter discusses the important guiding principles for such a framework, including those derived from the precautionary principle, life cycle thinking, and stakeholder involvement, and outlines the components of a harmonised risk governance approach in the food sector. These include an increased emphasis on safety research and a review of the existing statutory provisions and incentive instruments. As regulatory measures have to be backed by a consequent perception of corporate responsibility and product stewardship on the part of the producers, risk minimisation measures need to be introduced at the R&D stage. Moreover, the need for an utmost transparency in risk regulation and risk communication provided by participatory processes is highlighted. The chapter suggests that the participatory processes must systematically explore and analyse more complex effects that may arise in practice in tandem with the development of nanotechnology applications in the food sector.
Knowns, Unknowns, and Unknown Unknowns
Authors: Chaudhry Qasim , Watkins Richard , Castle Laurence
Published: April 2010

This concluding chapter draws upon the discussion on different aspects of nanotechnologies presented in the preceding chapters. It looks at the relevant materials, products and applications objectively, and analyses the likely benefits and potential risks to the consumer. It concludes that application of nanotechnologies would bring a number of subtle but far-reaching benefits to the consumer, in terms of innovative, healthy, and tasteful food products. It also stresses that a distinction needs to be made between 'soft’ (soluble, digestible) and ‘hard’ (insoluble, indigestible, biopersistent) nanomaterials. It argues that whilst applications using ‘hard’ nanomaterials would need detailed case-by-case safety evaluations, the development of 'soft’ food nanostructures need not require extensive safety testing. The chapter also wraps up the discussion on consumer attitudes towards new technologies in food, and discusses how some of the nanotechnology applications may be viewed by the consumer. Drawing upon the assessment of regulatory frameworks, the chapter presents suggestions for a way forward. It emphasises that many of the new developments may be regulated through the food industry's best practices and self-regulation, and that there is a need for public engagement to build confidence, trust, and acceptance of the new technological developments.
A novel HPLC-based approach makes possible the spatial characterization of cellular PtdIns5P and other phosphoinositides
Authors: Sarkes Deborah , Rameh Lucia E.
Published: April 2010

PtdIns5P was discovered in 1997 [Rameh, Tolias, Duckworth and Cantley (1997) Nature 390, 192–196], but still very little is known about its regulation and function. Hitherto, studies of PtdIns5P regulation have been hindered by the inability to measure cellular PtdIns5P using conventional HPLC, owing to poor separation from PtdIns4P. In the present paper we describe a new HPLC method for resolving PtdIns5P from PtdIns4P, which makes possible accurate measurements of basal and inducible levels of cellular PtdIns5P in the context of other phosphoinositides. Using this new method, we found that PtdIns5P is constitutively present in all cells examined (epithelial cells, fibroblasts and myoblasts, among others) at levels typically 1–2% of PtdIns4P levels. In the β-pancreatic cell line BTC6, which is specialized in insulin secretion, PtdIns5P levels were higher than in most cells (2.5–4% of PtdIns4P). Using subcellular fractionation, we found that the majority of the basal PtdIns5P is present in the plasma membrane, but it is also enriched in intracellular membrane compartments, especially in SER (smooth endoplasmic reticulum) and/or Golgi, where high levels of PtdIns3P were also detected. Unlike PtdIns3P, PtdIns5P was also found in fractions containing very-low-density vesicles. Knockdown of PIP4K (PtdIns5P 4-kinase) leads to accumulation of PtdIns5P in light fractions and fractions enriched in SER/Golgi, whereas treatment with Brefeldin A results in a subtle, but reproducible, change in PtdIns5P distribution. These results indicate that basal PtdIns5P and the PtdIns5P pathway for PtdIns(4,5)P2 synthesis may play a role in Golgi-mediated vesicle trafficking.
Coulomb-modified equilibrium and nonequilibrium properties in a double quantum dot Aharonov–Bohm–Fano interference device
Authors: Gong Weijiang , Xie Xuefeng , Wei Guozhu
Published: April 2010

In this paper, the Coulomb-induced changes of electronic transport through a double quantum dot (QD) Aharonov–Bohm–Fano interferometer are discussed. For the linear-transport case, the variation of Coulomb interaction in the reference-channel QD can remarkably modify the sign of the Fano parameter, which leads to the change in Fano interference, including the increase or decrease in the symmetry of the Fano lineshape, as well as the inversion of the Fano lineshape. When both the QD levels are adjustable, the Coulomb-induced splitting of the reference channel induces the destruction of Fano interference; whereas two blurry Fano lineshapes may appear in the conductance spectra when the many-body effect in the resonant-channel QD is also considered. Interestingly, in the absence of magnetic field, when the different-strength electron interactions make one pair of QD levels of different channels the same, the corresponding resonant state becomes a vacuum state. As for the nonlinear electron transport, the Fano lineshapes emerge in the differential conductance spectra when the resonant-channel QD level is adjusted to the vicinity of the chemical potential of either lead, except for the case where it encounters the reference-channel QD level. The presented Coulomb interactions also play a nontrivial role in the appearance of the negative differential conductance.
Hilbert-space treatment of incoherent, time-resolved spectroscopy. II. Pathway description of optical multiple population-period transient spectroscopy
Authors: Berg Mark A.
Published: April 2010

This paper applies the general methods developed in the previous paper (Paper I) to the case of one-photon, dipole transitions of a molecular solute. The results generalize transient-grating spectroscopy to an arbitrarily number of dimensions. Transition and detection operators are derived, and their matrix elements are calculated in the complex-valued basis set developed in Paper I. Selection rules make it possible to analyze which incoherent pathways, and thus which correlation functions, contribute to an N-dimensional multiple population-period transient spectroscopy experiment. Irreducible-tensor methods allow the amplitudes of the contributing orientational-correlation functions to be calculated for arbitrary polarization conditions. A second-rank polarization tensor is used to describe the polarization of the pair of beams creating or detecting a grating. Several known results for one-dimensional experiments are rederived in this formalism to provide examples of its use.
Ergodicity and Gaussianity for spherical random fields
Authors: Marinucci Domenico , Peccati Giovanni
Published: April 2010

We investigate the relationship between ergodicity and asymptotic Gaussianity of isotropic spherical random fields in the high-resolution (or high-frequency) limit. In particular, our results suggest that under a wide variety of circumstances the two conditions are equivalent, i.e., the sample angular power spectrum may converge to the population value if and only if the underlying field is asymptotically Gaussian in the high-frequency sense. These findings may shed some light on the role of cosmic variance in cosmic microwave background radiation data analysis.
Polarized pressure dependence of the anisotropic dielectric functions of highly oriented poly(p-phenylene vinylene)
Authors: Morandi V. , Galli M. , Marabelli F. , Comoretto D.
Published: April 2010

In this work, we combined an experimental technique and a detailed data analysis to investigate the influence of an applied pressure on the anisotropic dielectric functions of highly oriented poly(p-phenylene vinylene) (PPV). The dielectric constants were derived from polarized reflectance spectra recorded through a diamond anvil cell up to 50 kbar. The presence of the diamond anvils strongly affects measured spectra requiring the development in an optical model able to take all spurious effects into account. A parametric procedure was then applied to derive the complex dielectric constants for both polarizations as a function of pressure. A detailed analysis of their pressure dependence allows addressing the role of intermolecular interactions and electron-phonon coupling in highly oriented PPV.
Electron-beam-induced alteration of the dielectric properties of sandwiched self-assembled organic monolayers
Authors: Balaur Eugeniu , Peele Andrew G.
Published: April 2010

Electrical transport through octadecyltrichlorosilane self-assembled monolayers sandwiched between a silicon substrate and an aluminum film was altered using electron-beams (e-beams) with different energies and doses. Under certain e-beam conditions, improvement of the dielectric performance was observed compared with the unmodified monolayers. This was ascribed to partial “healing” of the gauche defects within the alkyl chains under the electron flux. It was also possible to vary the barrier height between 2 and 2.35 eV, an effect attributed to the creation of amorphous carbon under prolonged exposure times. Factors that influenced these effects were identified and discussed.
Transport equations in tokamak plasmas
Authors: Callen J. D. , Hegna C. C. , Cole A. J.
Published: April 2010

Tokamak plasma transport equations are usually obtained by flux surface averaging the collisional Braginskii equations. However, tokamak plasmas are not in collisional regimes. Also, ad hoc terms are added for neoclassical effects on the parallel Ohm’s law, fluctuation-induced transport, heating, current-drive and flow sources and sinks, small magnetic field nonaxisymmetries, magnetic field transients, etc. A set of self-consistent second order in gyroradius fluid-moment-based transport equations for nearly axisymmetric tokamak plasmas has been developed using a kinetic-based approach. The derivation uses neoclassical-based parallel viscous force closures, and includes all the effects noted above. Plasma processes on successive time scales and constraints they impose are considered sequentially: compressional Alfvén waves (Grad–Shafranov equilibrium, ion radial force balance), sound waves (pressure constant along field lines, incompressible flows within a flux surface), and collisions (electrons, parallel Ohm’s law; ions, damping of poloidal flow). Radial particle fluxes are driven by the many second order in gyroradius toroidal angular torques on a plasma species: seven ambipolar collision-based ones (classical, neoclassical, etc.) and eight nonambipolar ones (fluctuation-induced, polarization flows from toroidal rotation transients, etc.). The plasma toroidal rotation equation results from setting to zero the net radial current induced by the nonambipolar fluxes. The radial particle flux consists of the collision-based intrinsically ambipolar fluxes plus the nonambipolar fluxes evaluated at the ambipolarity-enforcing toroidal plasma rotation (radial electric field). The energy transport equations do not involve an ambipolar constraint and hence are more directly obtained. The “mean field” effects of microturbulence on the parallel Ohm’s law, poloidal ion flow, particle fluxes, and toroidal momentum and energy transport are all included self-consistently. The final comprehensive equations describe radial transport of plasma toroidal rotation, and poloidal and toroidal magnetic fluxes, as well as the usual particle and energy transport.
Absolute optical extinction measurements of single nano-objects by spatial modulation spectroscopy using a white lamp
Authors: Billaud Pierre , Marhaba Salem , Grillet Nadia , Cottancin Emmanuel , Bonnet Christophe , Lermé Jean , Vialle Jean-Louis , Broyer Michel , Pellarin Michel
Published: April 2010

This article describes a high sensitivity spectrophotometer designed to detect the overall extinction of light by a single nanoparticle (NP) in the 10−4–10−5 relative range, using a transmission measurement configuration. We focus here on the simple and low cost scheme where a white lamp is used as a light source, permitting easy and broadband extinction measurements (300–900 nm). Using a microscope, in a confocal geometry, an increased sensitivity is reached thanks to a modulation of the NP position under the light spot combined with lock-in detection. Moreover, it is shown that this technique gives access to the absolute extinction cross-sections of the single NP provided that the incident electromagnetic field distribution experienced by the NP is accurately characterized. In this respect, an experimental procedure to characterize the light spot profile in the focal plane, using a reference NP as a probe, is also laid out. The validity of this approach is discussed and confirmed by comparing experimental intensity distributions to theoretical calculations taking into account the vector character of the tightly focused beam. The calibration procedure permitting to obtain the absolute extinction cross-section of the probed NP is then fully described. Finally, the force of the present technique is illustrated through selected examples concerning spherical and slightly elongated gold and silver NPs. Absolute extinction measurements are found to be in good consistency with the NP size and shape independently obtained from transmission electron microscopy, showing that spatial modulation spectroscopy is a powerful tool to get an optical fingerprint of the NP.
The binary invariant differential operators on weighted densities on the superspace R1∣n and cohomology
Authors: Ben Ammar Mabrouk , Ben Fraj Nizar , Omri Salem
Published: April 2010

Over the (1,n)-dimensional real superspace, n>1, we classify K(n)-invariant binary differential operators acting on the superspaces of weighted densities, where K(n) is the Lie superalgebra of contact vector fields. This result allows us to compute the first differential cohomology of K(n) with coefficients in the superspace of linear differential operators acting on the superspaces of weighted densities—a superization of a result by Feigin and Fuchs [“Homology of the Lie algebras of vector fields on the line,” Funct. Anal. Appl. 14, 201 (1980)]. We explicitly give 1-cocycles spanning these cohomology spaces.
Comment on “On the imaginary-real ratio rule of power spectra” [J. Math. Phys. 50, 063301 (2009)]
Authors: Chen Yong
Published: April 2010

For the three-state ergodic Markov process, the condition of all the fluctuation spectra (i.e., power spectra) with respect to real observables being monotonic over [0,+∞) [Y. Chen, Fluct. Noise Lett. 7, L181 (2007) (Theorem 2.6)] is deduced from Theorem 1 of Qian and Xie [J. Math. Phys. 50, 063301 (2009)]. In addition, we present two examples using Theorem 3 of Qian and Xie [J. Math. Phys. 50, 063301 (2009)].