bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Analysis of Nutritional Content of Prickly Pads (Opuntia ficus indica) at Varied Ages in an Organic Harvest
Authors: Hernández-Urbiola Margarita I. , Pérez-Torrero Esther , Rodríguez-García Mario E.
Published: April 2011

Opuntia ficus indica, also known as prickly pads, are an important part of the human diet and are also used as forage for livestock. This is an interesting vegetable due the environmental conditions in which it grows and its resistance to climatic extremes; however, little is known about its nutritional properties, especially in the later stages of maturity. The objective of this study was to determine the composition of organic prickly pads (Opuntia ficus indica) at differing stages of growth maturity. Chemical proximate analysis and mineral constituent analysis at different maturation stages were carried out in this investigation. As a result, older prickly pads were found to be an important source of nutritional components such as calcium.
Electrochemically Formed Porous Silica
Authors: Chazalviel Jean-Noël , Ozanam François
Published: April 2011

Controlled electrochemical formation of porous silica can be realized in dilute aqueous, neutral-pH, fluoride medium. Formation of a porous film is initiated by sweeping the potential applied to silicon to values higher than 20 V. Film formation, reaching a steady state, may be pursued in a wide range of potentials, including lower potentials. The origin of a threshold potential for porous film initiation has been explained quantitatively. All of the films appear mesoporous. Films grown at high potentials exhibit a variety of macrostructures superimposed on the mesoporosity. These macrostructures result from selective dissolution of silica induced by local pH lowering due to oxygen evolution. Films grown at potentials lower than 15 V appear uniform on the micrometer scale. However, all of the films also exhibit a stratified structure on the scale of a few tens of nanometres. This periodic structure can be traced back to the oscillatory behavior observed during the electrochemical dissolution of silicon in fluoride medium. It suggests that periodic breaking of the growing film may be responsible for this morphology.
Deoxyuridines from the Marine Sponge Associated Actinomycete Streptomyces microflavus
Authors: Li Ke , Li Qiao-Lian , Ji Nai-Yun , Liu Bo , Zhang Wei , Cao Xu-Peng
Published: April 2011

One new nucleoside derivative, named 3-acetyl-5-methyl-2′-deoxyuridine (1), along with two known compounds 3,5-dimethyl-2′-deoxyuridine (2) and 3-methyl-2′-deoxyuridine (3), were isolated from the cultures of Streptomyces microflavus. This strain was an associated actinomycete isolated from the marine sponge Hymeniacidon perlevis collected from the coast of Dalian (China). Their structures were elucidated by detailed NMR and MS spectroscopic analysis as well as comparison with literature data.
Reassignment of the Structures of Products Produced by Reactions of the Product Believed To Be 2-(1-Phenyl-2-Thiocyanatoethylidene)-malononitrile with Electrophiles
Authors: Al-Mousawi Saleh Mohammed , Moustafa Moustafa Sherief , Elnagdi Mohamed Hilmy
Published: April 2011

The reactivity of the product believed to be 2-(1-phenyl-2-thiocyanato-ethylidene)malononitrile toward a variety of electrophilic and nucleophilic reagents is reported.
Synthesis, Singlet Oxygen Photogeneration and DNA Photocleavage of Porphyrins with Nitrogen Heterocycle Tails
Authors: Zheng Yun-Man , Wang Kai , Li Tian , Zhang Xiu-Lan , Li Zao-Yin
Published: April 2011

Eight novel compounds were prepared by reaction of 5-(bromo- propoxyphenyl)-10,15,20-triphenylporphyrin with oxazole thiols, 1,3,4-oxadiazole thiols and 1,3,4-thiadiazole thiols, and their structures confirmed by UV-vis, IR, 1H-NMR, MS and elemental analysis. The assessment of indirectly measured 1O2 production rates against 5,10,15,20-tetraphenyl porphyrin (H2TPP) were described and the relative singlet oxygen production yields were：porphyrin 5 > porphyrins 1, 3, 4, 6-8, H2TPP > porphyrin 2. Porphyrin 4 and porphyrin 7 showed substantial photocleavage activities toward DNA, with over 75% cleavage observed at 40 µM. It suggested that these those porphyrins with nitrogen heterocycle tails are potential photosensitive agents.
Phage Display of Combinatorial Peptide Libraries: Application to Antiviral Research
Authors: Castel Guillaume , Chtéoui Mohamed , Heyd Bernadette , Tordo Noël
Published: April 2011

Given the growing number of diseases caused by emerging or endemic viruses, original strategies are urgently required: (1) for the identification of new drugs active against new viruses and (2) to deal with viral mutants in which resistance to existing antiviral molecules has been selected. In this context, antiviral peptides constitute a promising area for disease prevention and treatment. The identification and development of these inhibitory peptides require the high-throughput screening of combinatorial libraries. Phage-display is a powerful technique for selecting unique molecules with selective affinity for a specific target from highly diverse combinatorial libraries. In the last 15 years, the use of this technique for antiviral purposes and for the isolation of candidate inhibitory peptides in drug discovery has been explored. We present here a review of the use of phage display in antiviral research and drug discovery, with a discussion of optimized strategies combining the strong screening potential of this technique with complementary rational approaches for identification of the best target. By combining such approaches, it should be possible to maximize the selection of molecules with strong antiviral potential.
Fluorescence Molecular Tomography: Principles and Potential for Pharmaceutical Research
Authors: Stuker Florian , Ripoll Jorge , Rudin Markus
Published: April 2011

Fluorescence microscopic imaging is widely used in biomedical research to study molecular and cellular processes in cell culture or tissue samples. This is motivated by the high inherent sensitivity of fluorescence techniques, the spatial resolution that compares favorably with cellular dimensions, the stability of the fluorescent labels used and the sophisticated labeling strategies that have been developed for selectively labeling target molecules. More recently, two and three-dimensional optical imaging methods have also been applied to monitor biological processes in intact biological organisms such as animals or even humans. These whole body optical imaging approaches have to cope with the fact that biological tissue is a highly scattering and absorbing medium. As a consequence, light propagation in tissue is well described by a diffusion approximation and accurate reconstruction of spatial information is demanding. While in vivo optical imaging is a highly sensitive method, the signal is strongly surface weighted, i.e., the signal detected from the same light source will become weaker the deeper it is embedded in tissue, and strongly depends on the optical properties of the surrounding tissue. Derivation of quantitative information, therefore, requires tomographic techniques such as fluorescence molecular tomography (FMT), which maps the three-dimensional distribution of a fluorescent probe or protein concentration. The combination of FMT with a structural imaging method such as X-ray computed tomography (CT) or Magnetic Resonance Imaging (MRI) will allow mapping molecular information on a high definition anatomical reference and enable the use of prior information on tissue’s optical properties to enhance both resolution and sensitivity. Today many of the fluorescent assays originally developed for studies in cellular systems have been successfully translated for experimental studies in animals. The opportunity of monitoring molecular processes non-invasively in the intact organism is highly attractive from a diagnostic point of view but even more so for the drug developer, who can use the techniques for proof-of-mechanism and proof-of-efficacy studies. This review shall elucidate the current status and potential of fluorescence tomography including recent advances in multimodality imaging approaches for preclinical and clinical drug development.
Gene Flow Among Modoc Sucker and Sacramento Sucker Populations in the Upper Pit River, California and Oregon
Authors: Smith Christian T. , Reid Stewart B. , Godfrey Lindsay , Ardren William R.
Published: April 2011

The Modoc sucker Catostomus microps received legal protection in the United States based partially on concerns that anthropogenic environmental changes had restricted migration among populations and catalyzed hybridization with a more abundant congener, the Sacramento sucker Catostomus occidentalis. We applied eight microsatellite markers to samples of both species collected from two tributaries to the Pit River, California (Ash Creek and Turner Creek), and one tributary of Goose Lake, Oregon (Thomas Creek). Modoc sucker populations in these three tributaries seemed to be largely isolated from one another: gene flow between Ash Creek and Turner Creek was no greater than that among these two creeks and Thomas Creek. In contrast, divergence estimates among collections of Sacramento suckers indicated greater gene flow between Ash Creek and Turner Creek than between either of these creeks and Thomas Creek. Samples collected at a single site (Ash Valley) were identified based on morphology as Modoc suckers, but genetic data suggested they were much more similar to Sacramento suckers. Interspecific hybrids were detected in all three tributaries. Collections of Modoc suckers yielded 0.0–3.9% hybrids, and collections of Sacramento suckers yielded 0.0–80.0% hybrids. The two collections with the greatest proportions of hybrids (54.5 and 80.0%) were both from tributaries to lower Thomas Creek, and neither of these tributaries is thought to have upstream populations of Modoc suckers. Based on 1) low levels of hybrid detection in all three tributaries, 2) the absence of hybrids from typical parental habitats (upstream habitats for Modoc suckers and Pit River mainstem for Sacramento suckers), and 3) highly significant RST (variance in allele size) values between the species, we conclude that hybridization is common but that significant introgression (i.e., loss of parental genotypes) has not occurred. We also note that hybridization, and subsequent introgression, may become a conservation concern in such cases when the habitat of one or both of these species is eliminated or modified.
TGF-β–Exposed Plasmacytoid Dendritic Cells Participate in Th17 Commitment
Authors: Bonnefoy Francis , Couturier Mélanie , Clauzon Amandine , Rémy-Martin Jean-Paul , Gaugler Béatrice , Tiberghien Pierre , Chen Wanjun , Saas Philippe , Perruche Sylvain
Published: April 2011

TGF-β is required for both Foxp3+ regulatory T cell (Treg) and Th17 commitment. Plasmacytoid DCs (pDC) have been shown to participate to both Treg and Th17 commitment as well. However, few studies have evaluated the direct effect of TGF-β on pDC, and to our knowledge, no study has assessed the capacity of TGF-β–exposed pDC to polarize naive CD4+ T cells. In this paper, we show that TGF-β–treated pDC favor Th17 but not Treg commitment. This process involves a TGF-β/Smad signal, because TGF-β treatment induced Smad2 phosphorylation in pDC and blockade of TGF-β signaling with the SD208 TGF-βRI kinase inhibitor abrogated Th17 commitment induced by TGF-β–treated pDC. Moreover, TGF-β mRNA synthesis and active TGF-β release were induced in TGF-β–treated pDC and anti–TGF-β Ab blocked Th17 commitment. Unexpectedly, TGF-β treatment also induced increased IL-6 production by pDC, which serves as the other arm for Th17 commitment driven by TGF-β–exposed pDC, because elimination of IL-6–mediated signal with either IL-6– or IL-6Rα–specific Abs prevented Th17 commitment. The in vivo pathogenic role of TGF-β–treated pDC was further confirmed in the Th17-dependent collagen-induced arthritis model in which TGF-β–treated pDC injection significantly increased arthritis severity and pathogenic Th17 cell accumulation in the draining lymph nodes. Thus, our data reveal a previously unrecognized effect of TGF-β–rich environment on pDC ability to trigger Th17 commitment. Such findings have implications in the pathogenesis of autoimmune diseases or immune responses against mucosal extracellular pathogens.
Macrophage Migration Inhibitory Factor: A Downregulator of Early T Cell-Dependent IFN-γ Responses in Plasmodium chabaudi adami (556 KA)-Infected Mice
Authors: Malu Diane Tshikudi , Bélanger Benoit , Desautels François , Kelendji Karine , Dalko Esther , Sanchez-Dardon Jaime , Leng Lin , Bucala Richard , Satoskar Abhay R. , Scorza Tatiana
Published: April 2011

Neutralization of macrophage migration inhibitory factor (MIF) increases anti-tumor cytotoxic T cell responses in vivo and IFN-γ responses in vitro, suggesting a plausible regulatory role for MIF in T cell activation. Considering that IFN-γ production by CD4+ T cells is pivotal to resolve murine malaria and that secretion of MIF is induced by Plasmodium chabaudi adami parasites, we investigated the effect of MIF deficiency on the infection with this pathogen. Infections with P. c. adami 556 KA parasites were more efficiently controlled in MIF-neutralized and MIF-deficient (knockout [KO]) BALB/c mice. The reduction in parasitemia was associated with reduced production of IL-4 by non-T/non-B cells throughout patent infection. At day 4 postinfection, higher numbers of activated CD4+ cells were measured in MIF KO mice, which secreted more IFN-γ, less IL-4, and less IL-10 than did CD4+ T cells from wild-type mice. Enhanced IFN-γ and decreased IL-4 responses also were measured in MIF KO CD4+ T cells stimulated with or without IL-12 and anti–IL-4 blocking Ab to induce Th1 polarization. However, MIF KO CD4+ T cells efficiently acquired a Th2 phenotype when stimulated in the presence of IL-4 and anti–IL-12 Ab, indicating normal responsiveness to IL-4/STAT6 signaling. These results suggest that by promoting IL-4 responses in cells other than T/B cells during early P. c. adami infection, MIF decreases IFN-γ secretion in CD4+ T cells and, additionally, has the intrinsic ability to render CD4+ T cells less capable of acquiring a robust Th1 phenotype when stimulated in the presence of IL-12.
The C-Terminally Encoded, MHC Class II-Restricted T Cell Antigenicity of the Helicobacter pylori Virulence Factor CagA Promotes Gastric Preneoplasia
Authors: Arnold Isabelle C. , Hitzler Iris , Engler Daniela , Oertli Mathias , Agger Else Marie , Müller Anne
Published: April 2011

Chronic infection with the human bacterial pathogen Helicobacter pylori causes gastritis and predisposes carriers to an increased gastric cancer risk. Consequently, H. pylori-specific vaccination is widely viewed as a promising strategy of gastric cancer prevention. H. pylori strains harboring the Cag pathogenicity island (PAI) are associated with particularly unfavorable disease outcomes in humans and experimental rodent models. We show in this study using a C57BL/6 mouse model of Cag-PAI+ H. pylori infection that the only known protein substrate of the Cag-PAI–encoded type IV secretion system, the cytotoxin-associated gene A (CagA) protein, harbors MHC class II-restricted T cell epitopes. Several distinct nonoverlapping epitopes in CagA’s central and C-terminal regions were predicted in silico and could be confirmed experimentally. CagA+ infection elicits CD4+ T cell responses in mice, which are strongly enhanced by prior mucosal or parenteral vaccination with recombinant CagA. The adoptive transfer of CagA-specific T cells to T cell-deficient, H. pylori-infected recipients is sufficient to induce the full range of preneoplastic immunopathology. Similarly, immunization with a cholera toxin-adjuvanted, CagA+ whole-cell sonicate vaccine sensitizes mice to, rather than protects them from, H. pylori-associated gastric cancer precursor lesions. In contrast, H. pylori-specific tolerization by neonatal administration of H. pylori sonicate in conjunction with a CD40L-neutralizing Ab prevents H. pylori-specific, pathogenic T cell responses and gastric immunopathology. We conclude that active tolerization may be superior to vaccination strategies in gastric cancer prevention.
Bioinformatics Identification of Modules of Transcription Factor Binding Sites in Alzheimer′s Disease‐Related Genes by In Silico Promoter Analysis and Microarrays
Authors: Augustin Regina , Lichtenthaler Stefan F. , Greeff Michael , Hansen Jens , Wurst Wolfgang , Trümbach Dietrich
Published: April 2011

The molecular mechanisms and genetic risk factors underlying Alzheimer′s disease (AD) pathogenesis are only partly understood. To identify new factors, which may contribute to AD, different approaches are taken including proteomics, genetics, and functional genomics. Here, we used a bioinformatics approach and found that distinct AD‐related genes share modules of transcription factor binding sites, suggesting a transcriptional coregulation. To detect additional coregulated genes, which may potentially contribute to AD, we established a new bioinformatics workflow with known multivariate methods like support vector machines, biclustering, and predicted transcription factor binding site modules by using in silico analysis and over 400 expression arrays from human and mouse. Two significant modules are composed of three transcription factor families: CTCF, SP1F, and EGRF/ZBPF, which are conserved between human and mouse APP promoter sequences. The specific combination of in silico promoter and multivariate analysis can identify regulation mechanisms of genes involved in multifactorial diseases.
Clinical Significance of FGF-23 in Patients with CKD
Authors: Russo Domenico , Battaglia Yuri
Published: April 2011

FGF23 is a bone-derived hormone that plays an important role in the regulation of phosphate and 1,25-dihydroxy vitamin D metabolism. FGF23 principally acts in the kidney to induce urinary phosphate excretion and suppress 1,25-dihydroxyvitamin D synthesis in the presence of FGF receptor 1 (FGFR1) and its coreceptor Klotho. In patients with chronic kidney disease (CKD), circulating FGF23 levels are progressively increased to compensate for persistent phosphate retention, but this results in reduced renal production of 1,25-dihydroxyvitamin D and leads to hypersecretion of parathyroid hormone. Furthermore, FGF23 is associated with vascular dysfunction, atherosclerosis, and left ventricular hypertrophy. This paper summarizes the role of FGF23 in the pathogenesis of mineral, bone, and cadiovascular disorders in CKD.
Calcium Mass Balances in Bicarbonate Hemodialysis
Authors: Basile Carlo
Published: April 2011

Dialysate calcium (Ca) concentration should be viewed as part of the integrated therapeutic regimen to control renal osteodystrophy and maintain normal mineral metabolism. The goals of this integrated approach are to keep the patient in a mild positive Ca mass balance (CaMB), to maintain normal serum Ca levels, to control plasma parathyroid hormone values to two to three times above normal levels, and to avoid soft-tissue calcifications. Thus, a correct net CaMB during hemodialysis (HD) is crucial in the treatment of renal osteodystrophy. Very few studies have been published which measured CaMBs in bicarbonate HD. This is mainly due to the technical difficulties in achieving an accurate measurement of CaMBs owing to the need for the collection of the total spent dialysate or of a proportional aliquot of it. Whereas no doubt exists about the fact that an inlet dialysate Ca concentration (CaD) of 1.75 mmol/L leads to a positive CaMB, more controversial is this issue, when dealing with a CaD of 1.50 mmol/L and, even more, when dealing with a CaD of 1.25 mmol/L. Another important issue is the appropriate CaD in long-hour slow-flow nocturnal HD. Finally, which CaMB should we study: ionized CaMB or total CaMB? This issue is largely discussed in the review.
Morphological Integration of the Modern Human Mandible during Ontogeny
Authors: Polanski Joshua M.
Published: April 2011

Craniofacial integration is prevalent in anatomical modernity research. Little investigation has been done on mandibular integration. Integration patterns were quantified in a longitudinal modern human sample of mandibles. This integration pattern is one of modularization between the alveolar and muscle attachment regions, but with age-specific differences. The ascending ramus and nonalveolar portions of the corpus remain integrated throughout ontogeny. The alveolar region is dynamic, becoming modularized according to the needs of the mandible at a particular developmental stage. Early in ontogeny, this modularity reflects the need for space for the developing dentition; later, modularity is more reflective of mastication. The overall pattern of modern human mandibular integration follows the integration pattern seen in other mammals, including chimpanzees. Given the differences incraniofacialintegration patterns between humans and chimpanzees, but the similarities inmandibularintegration, it is likely that the mandible has played the more passive role in hominin skull evolution.
Osteoporosis Knowledge, Self-Efficacy, and Beliefs among College Students in the USA and China
Authors: Ford M. Allison , Bass Martha , Zhao Yan , Bai Jin-Bing , Zhao Yue
Published: April 2011

This study investigated differences in osteoporosis knowledge, self-efficacy, and health beliefs among Chinese and American college students. Information obtained will be used in developing osteoporosis prevention programs for younger adults.Methods. Chinese () and US () college students completed the Osteoporosis Health Belief, Self-Efficacy, and Knowledge Tests.Results. Differences were seen in osteoporosis knowledge (, ), exercise knowledge (, ), calcium knowledge (, ), perceptions of exercise benefits (, ), calcium benefits (, ), exercise barriers (, ), calcium barriers (, ), and exercise self-efficacy (, ).Conclusion. US college students know more about osteoporosis and its risk factors; however, there are similarities in perception of risk between US and Chinese students. Chinese students perceive greater barriers to reducing their risk through exercise and dietary calcium intake.
Physical Activity and Hip Fracture Disability: A Review
Authors: Marks Ray
Published: April 2011

Objective. The present paper examines pertinent literature sources published in the peer-reviewed English language between 1980 and November 1, 2010 concerning hip fractures. The aim was to highlight potential intervention points to offset the risk of incurring a hip fracture and its attendant disability.Methods. An in-depth search of the literature using the key terms: disability, epidemiology, hip fracture, prevention, and risk factors was conducted, along with data from the author's research base detailing the disability associated with selected hip fracture cases. All articles that dealt with these key topics were reviewed, and relevant data were tabulated and analyzed.Results. Hip fractures remain an important but potentially preventable public health problem. Among the many related remediable risk factors, low physical activity levels are especially important. Related determinants of suboptimal neuromuscular function also contribute significantly to hip fracture disability.Conclusion. Physical activity participation can help to reduce the prevalence and excess disability of hip fractures and should be encouraged.
A Study of the Persistence ofMycobacterium bovisin the Environment under Natural Weather Conditions in Michigan, USA
Authors: Fine Amanda E. , Bolin Carole A. , Gardiner Joseph C. , Kaneene John B.
Published: April 2011

Reisolation ofMycobacterium bovisfrom inoculated substrates was used to follow the persistence of viableM. bovisbacteria exposed to natural weather conditions over a 12-month period. Environmental factors were recorded continuously, and factors affectingM. bovispersistence (i.e., temperature, season, and substrate) were studied using survival analysis and Cox's proportional hazards regression. Persistence ofM. bovisin the environment was significantly shorter in the spring/summer season, characterized by the highest average daily temperatures over the 12-month period.M. bovispersisted up to 88 days in soil, 58 days in water and hay, and 43 days on corn. These studies demonstrate thatM. bovisbacteria persist long enough to represent a risk of exposure for cattle and/or wildlife and strengthen evidence that suggests cattle farm biosecurity and efforts to eliminate supplemental feeding of white-tailed deer will decrease the risk of bovine TB transmission among and between cattle and deer populations.
Atrial Fibrillation Ablation without Interruption of Anticoagulation
Authors: Santangeli Pasquale , Di Biase Luigi , Sanchez Javier E. , Horton Rodney , Natale Andrea
Published: April 2011

Atrial fibrillation (AF) can be cured by pulmonary vein antrum isolation (PVAI) in a substantial proportion of patients. The high efficacy of PVAI is partially undermined by a small but concrete periprocedural risk of complications, such as thromboembolic events and bleeding. A correct management of anticoagulation is essential to prevent such complications. Performing PVAI without interruption of oral anticoagulation has been demonstrated feasible by our group in previous studies. Recently, we reported that continuation of therapeutic warfarin during radiofrequency catheter ablation consistently reduces the risk of periprocedural stroke/transient ischemic attack without increasing the risk of hemorrhagic events. Of note, interrupting warfarin anticoagulation may actually increase the risk of stroke even when bridged with heparin. The latter strategy is also associated with an increased risk of minor bleeding. With regard to major bleeding, we found no significant difference between patients with a therapeutic INR and those who were bridged with heparin. Therefore, continuation of therapeutic warfarin during ablation of AF appears to be the best anticoagulation strategy. In this paper we summarize our experience with AF ablation without interruption of anticoagulation.
Primary Pericardial Sarcoma: A Case Report and a Brief Review
Authors: Pakala Aneesh , Gupta Raghav , Lazzara Ralph
Published: April 2011

There are very few cases of primary pericardial sarcomas reported in the English literature. Pericardial tumors, like other cardiac tumors, are most likely to be metastatic in nature and are an extension of primary tumors from the surrounding structures. Sarcomas are the most common primary pericardial tumors. Surgical eradication of the tumor is considered to be the treatment of choice. We are presenting a case of a primary pericardial, high-grade pleomorphic undifferentiated sarcoma that was diagnosed at our institution. We discuss the available diagnostic modalities and also shed light on alternative therapies when patients are not ideal surgical candidates.
Pharmacological Management of Atrial Fibrillation: One, None, One Hundred Thousand
Authors: Lucà Fabiana , La Meir Mark , Rao Carmelo Massimiliano , Parise Orlando , Vasquez Ludovico , Carella Rocco , Lorusso Roberto , Daniela Benedetto , Maessen Jos , Gensini Gian Franco , Gelsomino Sandro
Published: April 2011

Abstract atrial fibrillation (AF) is associated with a significant burden of morbidity and increased risk of mortality. Antiarrhythmic drug therapy remains a cornerstone to restore and maintain sinus rhythm for patients with paroxysmal and persistent AF based on current guidelines. However, conventional drugs have limited efficacy, present problematic risks of proarrhythmia and cause significant noncardiac organ toxicity. Thus, inadequacies in current therapies for atrial fibrillation have made new drug development crucial. New antiarrhythmic drugs and new anticoagulant agents have changed the current management of AF. This paper summarizes the available evidence regarding the efficacy of medications used for acute management of AF, rhythm and ventricular rate control, and stroke prevention in patients with atrial fibrillation and focuses on the current pharmacological agents.
Chemical composition of rainwater at Maldives Climate Observatory at Hanimaadhoo (MCOH)
Authors: Das R. , Granat L. , Leck C. , Praveen P. S. , Rodhe H.
Published: April 2011

Abstract. Water-soluble inorganic components in rain deposited at the Maldives Climate Observatory Hanimaadhoo (MCOH) were examined to determine seasonality and possible source regions. The study, which is part of the Atmospheric Brown Cloud (ABC) project, covers the period June 2005 to December 2007. Air mass trajectories were used to separate the data into situations with transport of air from India and adjacent parts of the Asian continent during the months December and January (Indian group) and those with southerly flow from the Indian Ocean during the summer monsoon season June to September (Marine group). A third trajectory group was identified with transport from the northern parts of the Arabian Sea and adjacent land areas during the months March, April and October (Arabian Sea group). The concentrations of nss-SO42−, NH4+ and NO3− were more than a factor of 4 higher in the Indian group than in the Marine group. The average rainwater pH was significantly lower in the Indian group (4.7) than in the Marine group (6.0). This shows a pronounced influence of continental pollutants during December and January. The origin of the very high concentration of nss-Ca2+ found in the Marine group – a factor of 7 higher than in the Indian group – is unclear. We discuss various possibilities including long-range transport from the African or Australian continents, local dust from nearby islands and calcareous plankton debris and exopolymer gels emitted from the ocean surface. The occurrence of NO3− and NH4+ in the Marine group suggests emissions from the ocean surface. Part of the NO3− could also be associated with lightning over the ocean. Despite the fact that the concentrations of nss-SO42−, NO3−, and NH4+ were highest in the Indian group the wet deposition was at least as big in the Marine group reflecting the larger amount of rainfall during the monsoon season. The annual wet deposition of NO3−, NH4+ and nss-SO42− at MCOH is about a factor of three lower than observed at rural sites in India.
Dynamical states of low temperature cirrus
Authors: Barahona D. , Nenes A.
Published: April 2011

Abstract. Low ice crystal concentration and sustained in-cloud supersaturation, commonly found in cloud observations at low temperature, challenge our understanding of cirrus formation. Heterogeneous freezing from effloresced ammonium sulfate, glassy aerosol, dust and black carbon are proposed to cause these phenomena; this requires low updrafts for cirrus characteristics to agree with observations and is at odds with the gravity wave spectrum in the upper troposphere. Background temperature fluctuations however can establish a "dynamical equilibrium" between ice production and sedimentation loss (as opposed to ice crystal formation during the first stages of cloud evolution and subsequent slow cloud decay) that explains low temperature cirrus properties. This newly-discovered state is favored at low temperatures and does not require heterogeneous nucleation to occur (the presence of ice nuclei can however facilitate its onset). Our understanding of cirrus clouds and their role in anthropogenic climate change is reshaped, as the type of dynamical forcing will set these clouds in one of two "preferred" microphysical regimes with very different susceptibility to aerosol.
Direct ecosystem fluxes of volatile organic compounds from oil palms in South-East Asia
Authors: Misztal P. K. , Nemitz E. , Langford B. , Di Marco C. F. , Phillips G. J. , Hewitt C. N. , MacKenzie A. R. , Owen S. M. , Fowler D. , Heal M. R. , Cape J. N.
Published: April 2011

Abstract. This paper reports the first direct eddy covariance fluxes of reactive biogenic volatile organic compounds (BVOCs) from oil palms to the atmosphere using proton-transfer-reaction mass spectrometry (PTR-MS), measured at a plantation in Malaysian Borneo. At midday, net isoprene flux constituted the largest fraction (84%) of all emitted BVOCs measured, at up to 30 mg m−2 h−1 over 12 days. By contrast, the sum of its oxidation products methyl vinyl ketone (MVK) and methacrolein (MACR) exhibited clear deposition, with a small average canopy resistance of 230 s m−1. Approximately 15% of the resolved BVOC flux from oil palm trees could be attributed to floral emissions, which are thought to be the largest reported biogenic source of estragole and possibly also toluene. Although on average the midday volume mixing ratio of estragole exceeded that of toluene by almost a factor of two, the corresponding fluxes of these two compounds were nearly the same, amounting to 0.81 and 0.76 mg m−2 h−1, respectively. By fitting the canopy temperature and PAR response of the MEGAN emissions algorithm for isoprene and other emitted BVOCs a basal emission rate of isoprene of 7.8 mg m−2 h−1 was derived. We parameterise fluxes of depositing compounds using a resistance approach using direct canopy measurements of deposition. We propose that it is important to include deposition in flux models, especially for secondary oxidation products, in order to improve flux predictions.
Observations of hydroxyl and peroxy radicals and the impact of BrO at Summit, Greenland in 2007 and 2008
Authors: Liao J. , Huey L. G. , Tanner D. J. , Brooks S. , Dibb J. E. , Stutz J. , Thomas J. L. , Lefer B. , Haman C. , Gorham K.
Published: April 2011

Abstract. The Greenland Summit Halogen-HOx (GSHOX) Campaign was performed in spring~2007 and summer~2008 to investigate the impact of halogens on HOx (=OH + HO2) cycling above the Greenland Ice Sheet. Chemical species including hydroxyl and peroxy radicals (OH and HO2 + ROx), ozone (O3), nitrogen oxide (NO), nitric acid (HNO2), nitrous acid (HONO), reactive gaseous mercury (RGM), and bromine oxide (BrO) were measured during the campaign. The median midday values of HO2 + RO2 and OH concentrations observed by chemical ionization mass spectrometry (CIMS) were 2.7 × 108 molec cm−3 and 3.0 × 106 molec cm−3 in spring 2007, and 4.2 × 108 molec cm−3 and 4.1 × 106 molec cm−3 in summer~2008. A basic photochemical 0-D box model highly constrained by observations of H2O, O3, CO, CH4, NO, and J values predicted HO2 + RO2 (R = 0.90, slope = 0.87 in 2007; R = 0.79, slope = 0.96 in 2008) reasonably well and under predicted OH (R = 0.83, slope = 0.72 in 2007; R = 0.76, slope = 0.54 in 2008). Constraining the model to HONO observations did not significantly change the predictions. Including bromine chemistry in the model constrained by observations of BrO improved the correlation between observed and predicted HO2 + RO2 and OH, and brought the average hourly OH and HO2+RO2 predictions closer to the observations. These model comparisons confirmed our understanding of the dominant HOx sources and sinks in this environment and indicated that BrO impacted the OH levels at Summit. Although, significant discrepancies between observed and predicted OH could not be explained by the measured BrO. Finally, observations of enhanced RGM were found to be coincident with under prediction of OH.
Assessing components of the natural environment of the Upper Danube and Upper Brahmaputra river basins
Authors: Lang S. , Kääb A. , Pechstädt J. , Flügel W.-A. , Zeil P. , Lanz E. , Kahuda D. , Frauenfelder R. , Casey K. , Füreder P. , Sossna I. , Wagner I. , Janauer G. , Exler N. , Boukalova Z. , Tapa R. , Lui J. , Sharma N.
Published: April 2011

Abstract. A comprehensive understanding of the interplay between the natural environment and the human dimension is one of the prerequisites to successful and sustaining IWRM practises in large river basins such as the Upper Brahmaputra river basin or the Upper Danube river basin. These interactions, their dynamics and changes, and the likely future scenarios were investigated in the BRAHMATWINN project with a series of tools from remote sensing and geoinformatics. An integrated assessment of main components of the natural environment in the two river basins as well as in five reference catchments within those basins, has led to the delineation of hydrological response units (HRUs). HRUs are spatial units bearing a uniform behaviour in terms of the hydrological response regime, as a function of physical parameters land use, soil type, water, vegetation cover and climate. Besides the delineated HRUs which are available in a spatially exhaustive manner for all reference catchments, the following information were provided as spatial layers: (1) uniform digital surface models of both the twinned basins and the reference catchments; (2) glacier areas and the magnitude of glacier loss; (3) mountain permafrost distribution and identification of areas particularly affected by permafrost thaw; (4) a consistent land use/land cover information in all reference catchments; and (5) the vulnerabilities of wetlands and groundwater in terms of anthropogenic impact and climate change.
Analysis of present IWRM in the Upper Brahmaputra and the Upper Danube River Basins
Authors: Flügel W.-A. , Bartosch A.
Published: April 2011

Abstract. Integrated Water Resources Management (IWRM) is a process which strives towards the sustainable management of water resources in river basins. The approach integrates insights and knowledge from various scientific disciplines comprising natural, socio-economic, and engineering sciences. These three pillars of sustainability are important components of this approach integrating the environmental, economic and social dimension. In the ideal IWRM case planning is based on the river basin scale and therefore is comparatively discussed herein for the two twinning BRAHMATWINN river basins, i.e. the Upper Danube River Basin (UDRB) in Europe and the Upper Brahmaputra River Basin (UBRB) in South Asia. In this chapter major challenges for the implementation of the IWRM process towards a sustainable management of water resources in the two UDRB and UBRB twinning river basins of the BRAHMATWINN project are analysed. The study revealed that in the UDRB the IWRM approach is already part of water management planning and the implementation of the EU Water Framework Directive (WFD) is a good example in this regard. Contrary in the UBRB the implementation of IWRM is just at the beginning phase, only recently is being discussed in the riparian states but has not been implemented in any way so far on the basin scale.
Development of responses based on IPCC and "what-if?" IWRM scenarios
Authors: Giannini V. , Ceccato L. , Hutton C. , Allan A. A. , Kienberger S. , Flügel W.-A. , Giupponi C.
Published: April 2011

Abstract. This work illustrates the findings of a participatory research process aimed at identifying responses for sustainable water management in a climate change perspective, in two river basins in Europe and Asia. The chapter describes the methodology implemented through local participatory workshops, aimed at eliciting and evaluating possible responses to flood risk, which were then assessed with respect to the existing governance framework. Socio-economic vulnerability was also investigated developing an indicator, whose future trend was analysed with reference to IPCC scenarios. The main outcome of such activities consists in the identification of Integrated Water Resource Management Strategies (IWRMS) based upon the issues and preferences elicited from local experts. The mDSS decision support tool was used to facilitate transparent and robust management of the information collected and communication of the outputs.
Biogeochemistry of manganese in Lake Matano, Indonesia
Authors: Jones C. , Crowe S. A. , Sturm A. , Leslie K. L. , MacLean L. C. W. , Katsev S. , Henny C. , Fowle D. A. , Canfield D. E.
Published: April 2011

Abstract. This study explores Mn biogeochemistry in a stratified, ferruginous lake. Intense Mn cycling occurs in the chemocline where Mn is recycled at least 15 times before sedimentation. The kinetics of Mn oxidation in Lake Matano are similar to other studied environments, implying that Mn oxidation is relatively insensitive to environmental parameters and may be controlled by similar mechanisms in diverse settings. The product of biologically catalyzed Mn oxidation in Lake Matano is birnessite. Although there is evidence for abiotic Mn reduction with Fe(II), Mn reduction likely occurs through a variety of pathways. The flux of Fe(II) is insufficient to balance the reduction of Mn at 125 m depth in the water column, and Mn reduction could be a significant contributor to CH4 oxidation. By combining results from synchrotron-based X-ray fluorescence and X-ray spectroscopy, extractions of sinking particles, and reaction transport modeling, we find the kinetics of Mn reduction in the lake's reducing waters are sufficiently rapid to preclude the deposition of Mn oxides from the water column to the sediments underlying anoxic water. Rather, Mn is likely sequestered in these sediments as pseudo kutnahorite. This has strong implications for the interpretation of the sedimentary Mn record.
Systematic study of the fresh water fluxes impact on the carbon cycle
Authors: Bouttes N. , Roche D. M. , Paillard D.
Published: April 2011

Abstract. During glacial periods, atmospheric CO2 concentration rapidly increases and decreases by around 15 ppm at the same time as climate experiments an abrupt cooling in the North Hemisphere and warming in the South Hemisphere. Such a climate change can be triggered in models by adding fresh water fluxes (FWFs) in the North Atlantic. Yet the impact on the carbon cycle is less straightforward, and previous studies give opposite results. Because both models and added fresh water fluxes were different in these studies, it prevents any direct comparison and hinders finding an explanation for these discrepancies. In this study we use the CLIMBER-2 coupled climate carbon model to explore the impact of different additional fresh water fluxes in various conditions, including the experiments previously performed with other models. We show that the CO2 changes caused by the fresh water flux events should be interpreted as a combination of oceanic and terrestrial processes. The initial state of the Atlantic Meridional Overturning Circulation (AMOC) prior to the addition of fresh water fluxes appears to play a crucial role. The rapid increase of CO2 observed in ice core data can only be accounted for when the export of North Atlantic Deep Water (NADW) is relatively slow. Additionally, the terrestrial and oceanic carbon reservoirs responses are a consequence of the climate change and most importantly of the "seesaw" effect. As the latter is different in the various models it results in widely different evolution of the vegetation and oceanic carbon reservoirs. The discrepancies between the different studies can thus be explained by a combination of these factors: initial climatic and carbon cycle states, characteristics of the added fresh water flux, AMOC initial state and model "seesaw" pattern.
A comparison of eddy-covariance and large aperture scintillometer measurements with respect to the energy balance closure problem
Authors: Liu S. M. , Xu Z. W. , Wang W. Z. , Jia Z. Z. , Zhu M. J. , Bai J. , Wang J. M.
Published: April 2011

Abstract. We analyzed the seasonal variations of energy balance components over three different surfaces: irrigated cropland (Yingke, YK), alpine meadow (A'rou, AR), and spruce forest (Guantan, GT). The energy balance components were measured using eddy covariance (EC) systems and a large aperture scintillometer (LAS) in the Heihe River Basin, China, in 2008 and 2009. We also determined the source areas of the EC and LAS measurements with a footprint model for each site and discussed the differences between the sensible heat fluxes measured with EC and LAS at AR. The results show that the main EC source areas were within a radius of 250 m at all of the sites. The main source area for the LAS (with a path length of 2390 m) stretched along a path line approximately 2000 m long and 700 m wide. The surface characteristics in the source areas changed with the season at each site, and there were characteristic seasonal variations in the energy balance components at all of the sites. The sensible heat flux was the main term of the energy budget during the dormant season. During the growing season, however, the latent heat flux dominated the energy budget, and an obvious "oasis effect" was observed at YK. The sensible heat fluxes measured by LAS at AR were larger than those measured by EC at the same site. This difference seems to be caused by the so-called energy imbalance phenomenon, the heterogeneity of the underlying surfaces, and the difference between the source areas of the LAS and EC measurements.
DREAM(D): an adaptive markov chain monte carlo simulation algorithm to solve discrete, noncontinuous, posterior parameter estimation problems
Authors: Vrugt J. A.
Published: April 2011

Abstract. Formal and informal Bayesian approaches are increasingly being used to treat forcing, model structural, parameter and calibration data uncertainty, and summarize hydrologic prediction uncertainty. This requires posterior sampling methods that approximate the (evolving) posterior distribution. We recently introduced the DiffeRential Evolution Adaptive Metropolis (DREAM) algorithm, an adaptive Markov Chain Monte Carlo (MCMC) method that is especially designed to solve complex, high-dimensional and multimodal posterior probability density functions. The method runs multiple chains in parallel, and maintains detailed balance and ergodicity. Here, I present the latest algorithmic developments, and introduce a discrete sampling variant of DREAM that samples the parameter space at fixed points. The development of this new code, DREAM(D), has been inspired by the existing class of integer optimization problems, and emerging class of experimental design problems. Such non-continuous parameter estimation problems are of considerable theoretical and practical interest. The theory developed herein is applicable to DREAM(ZS) (Vrugt et al., 2011) and MT-DREAM(ZS) (Laloy and Vrugt, 2011) as well. Two case studies involving a sudoku puzzle and rainfall – runoff model calibration problem are used to illustrate DREAM(D).
Hydrological response of a small catchment burned by experimental fire
Authors: Stoof C. R. , Vervoort R. W. , Iwema J. , van den Elsen E. , Ferreira A. J. D. , Ritsema C. J.
Published: April 2011

Abstract. Fire can considerably change hydrological processes, increasing the risk of extreme flooding and erosion events. Although hydrological processes are largely affected by scale, catchment-scale studies on the hydrological impact of fire are scarce, and nested approaches are rarely used. Taking a unique approach, we performed a catchment-scale experimental fire to improve insight into the drivers of fire impact on hydrology. In north-central Portugal, rainfall, canopy interception, streamflow and soil moisture were monitored in shrub-covered paired catchments pre- and post-fire. Post-fire runoff coefficients were higher than pre-fire, and fire changed the rainfall-streamflow relationship – although the increase in streamflow was only significant at the subcatchment-scale. Fire also increased the response of topsoil moisture to rainfall, and caused more rapid drying of topsoils after rain events. Since soil physical changes due to fire were not apparent, we suggest that changes resulting from vegetation removal played an important role in increasing streamflow after fire, namely: (1) increased effective rainfall and decreased transpiration – increasing the amount of water available for (sub)surface runoff, (2) more rapid development of soil water repellency and decreased surface water storage – increasing overland flow risk, (3) more rapid breakdown of post-fire soil water repellency – increasing infiltration during extended rain events. Results stress that fire impact on hydrology is largely affected by scale, highlight the hydrological impact of fire on small scales, and emphasize the risk of overestimating fire impact when upscaling plot-scale studies to the catchment-scale. Finally, they increase understanding of the processes contributing to post-fire flooding and erosion events.