bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thin‐layer Chromatography of Plants, with Chemical and Biological Detection Methods
Authors: Urbain Aurélie , Simões‐Pires Claudia Avello 
Published: June 2014

AbstractThin‐layer chromatography (TLC) is a widespread separation technique in the field of plant analysis and offers multiple advantages. This versatile technique can provide useful information about the qualitative or semiquantitative chemical composition of a mixture, thanks to coupling, with the detection and spectroscopic techniques and devices for image treatment. Moreover, it can contribute to the detection of biological activity by combining chromatography with bioassays, such as antimicrobial or enzyme inhibition tests. This procedure, providing simultaneous chromatographic separation andin situassessment of a given biological activity, is namedTLCbioautography. The major advantage of this technique is the ability to locate active substances from a complex mixture without prior sample purification. This avoids time‐consuming and tedious isolation of already‐known or inactive compounds. As this method is simple and cost effective, it is suitable for preliminary rapid screening to detect potential activity, as well as being a useful monitoring tool to track the bioguided isolation of active components. In this chapter, we focus on up‐to‐dateTLCbioautographic assays, detail their mechanisms and applications in the field of natural drug discovery, and discuss the recent advances of this method that might appear at first glance to be a trivial approach.
On‐line and At‐line Liquid Chromatography Nuclear Magnetic Resonance and Related Micro‐Nuclear Magnetic Resonance Methods in Natural Product Analysis
Authors: Bohni Nadine , Queiroz Emerson F. , Wolfender Jean‐Luc 
Published: June 2014

AbstractNuclear magnetic resonance spectroscopy (NMR) is essential for thede novostructure identification of natural products. This technique can be directly or indirectly hyphenated to high performance liquid chromatography (HPLC) leading to efficientLC‐NMRplatforms.NMRis, however, a very insensitive detection method compared to mass spectrometry and several strategies for its efficient hyphenation withHPLChave been developed. This includes on‐lineLC‐NMR,SPE‐NMR, or other at‐line approaches involving microflow probes or microtubes in combination with cryoprobes. All of these various technologies and their potentials and limitations in the field of natural product research are described. Recent applications involving other complementary detection methods such asLC‐MSor biologicalHPLCprofiling illustrate its utilization.
Mycotoxins Contamination in Food: Alternative Plant Preservatives, Legislation and Detection Methods
Authors: Zuzarte Monica R. , Martins Ana P. , Gonçalves Maria J. , Salgueiro Lígia R. 
Published: June 2014

AbstractCrops, foods, and raw materials are vulnerable to contamination by many fungi. Besides reduction in crop yield and loss of quality, some fungi are a source of mycotoxins. The major types of mycotoxins include aflatoxins, ochratoxins, fumonisins, patulin, trichothecenes, and zearalenone. The economic consequences of contamination by mycotoxins are profound, representing a common health hazard for humans and animals because of both chronic and acute toxicological manifestations.As it is nearly impossible to prevent contamination by mycotoxins, the food industry has established internal monitoring methods to comply with the legal regulatory limits, leading to the exploitation of alternative food processing and preservation techniques. As secondary plant metabolites are biodegradable to nontoxic products, they are potentially useful in integrated pest management programs and could allow the development of a new class of safer disease‐control substances.This chapter aims to update the knowledge on contamination of food and storage products by mycotoxins. A summary of the main types of mycotoxins present in food and crop products, plant metabolites that could be potentially applied because of their antifungal properties, food safety legislation on this matter, and analytical methods used to detect mycotoxins are presented. Copyright © 2014 John Wiley & Sons, Ltd.
Catalysis of Organic Transformations by Gold Nanoparticles Supported on Metal Oxides
Authors: Stratakis Manolis , Garcia Hermenegildo 
Published: June 2014

AbstractSupported gold nanoparticles on metal oxides surfaces are powerful catalysts applicable to a variety of organic transformations. Following the first observation that they activate molecular oxygen towards oxidation of CO or organic compounds (e.g. alcohols) under mild conditions, it was uncovered during the past decade that Au nanoparticles activate alkynes, silanes, dihydrogen, exhibit oxophilic activity, catalyze CC bond forming cross‐coupling reactions and transfer hydrogenation processes, thus mimicking the catalytic activity of Pd, Pt, and other late transition metals.
Organic tetroxides and mechanism of peroxy radical recombination
Authors: Khursan Sergey L. 
Published: June 2014

AbstractThe chemical properties of organic tetroxides, that is, compounds of a general formula ROOOOR (R = H or organic radical) are discussed. The following tetroxides are considered: hydrogen tetroxide HOOOOH, dialkyl tetroxides ROOOOR, hydrotetroxides ROOOOH, and five‐membered cyclic tetroxides—tetroxolanes. Hydrogen tetroxide is formedviaself‐reaction of HOO·radicals on singlet PES; hydroperoxy radical interaction plays an important role in the chemistry of atmosphere. The formation and subsequent decay of tetroxides are discussed in detail. Similar self‐reaction of alkylperoxy radicals leads to organic tetroxides. Its irreversible transformation occurs in two directions depending on the tetroxide structure: the facile homolysis of ROOOOR bond or the induced by αCH bond radical decomposition of tetroxide into hydroperoxy, alkoxy radicals, and carbonyl compound. The latter interaction is the key step in the new mechanism of peroxy radical recombination suggested on the base of extensive analysis of available literature. Hydrotetroxides show properties similar to both HOOOOH and dialkyl tetroxides. A possibility of tetroxolane generation in the reaction of ozone with carbonyl compounds is discussed.
Public Health Issues in Disaster Management
Authors: Burkle Frederick M. 
Published: June 2014

AbstractPublic health issues are critical elements of disaster management, especially large‐scale disasters where the essential public health infrastructure and social protections are destroyed or compromised. Public health consequences usually lead to indirect, preventable, or excess mortality. If basic prevention and preparedness responsibilities are not met, indirect consequences may exceed the direct consequences, especially in war, post‐conflict situations, and large‐scale natural and man‐made disasters.
Screening
Authors: Pinell Patrice 
Published: June 2014

AbstractThis paper analyzes from a sociohistorical perspective the evolution of screening policies. The analysis focuses first on the role of screening in social hygiene policies that underpin the fight against infectious diseases. The question of the social conditions of compulsory screening is discussed. Second, the changes in screening policies are analyzed, in particular those linked to the decline of infectious diseases and the rise of chronic diseases. Third, the entry focuses on the AIDS epidemic and the renewal of mass screening.
Disability
Authors: Watson Nick 
Published: June 2014

Abstract
Disability is part of the human condition and disabled people make up the world's largest minority group. According to the World Health Survey, around 15 percent of the world's population (just over one billion people) have some form of impairment and of these between 110 million and 190 million have significant difficulties in functioning. It is something that will affect almost everyone; everybody will at some point in their life have an impairment, which may be either temporary or permanent; almost every family will have a disabled member; and many non‐disabled people will take responsibility for supporting and caring for a disabled relative or friend. The numbers of disabled people are increasing, largely, although not solely, due to demographic changes, with increases in the prevalence of chronic conditions associated with aging, coupled with advances in medical science and new medical interventions which can prolong life.
Micro‐computed tomography assessment of vertebral column defects in retinoic acid‐Induced rat model of myelomeningocele
Authors: Barbe Mary F. , Adiga Radhika , Gordiienko Oleg , Pleshko Nancy , Selzer Michael E. , Krynska Barbara 
Published: June 2014

BackgroundMyelomeningocele (MMC) is a common congenital malformation and the most severe form of spina bifida characterized by the protrusion of spinal cord and meninges through the spinal defect. Our objective was to improve the assessment of congenital vertebral defects in animal models of MMC using three‐dimensional high resolution micro‐computed tomography (micro‐CT) imaging and quantitative digital analyses methods.MethodsLumbosacral MMC was induced in fetal rats by exposure of pregnant mothers at embryonic day 10 (E10) to all‐trans retinoic acid, and rats were examined at term (embryonic day 22). The axial skeleton was examined in an MMC model for the first time using ex vivo micro‐CT at 10 μm voxel resolution to allow high resolution two‐dimensional and three‐dimensional characterization of anomalies in lumbosacral vertebrae, and quantitative assessment of distances between dorsal vertebral arches in lumbosacral regions in MMC rats, compared with normal controls.ResultsWe observed, in detail, skeletal defects in lumbosacral vertebra of MMC rats, including in the morphology of individual dorsal vertebral arches. Use of high resolution micro‐CT has also enabled us to identify the delayed (nonfused) or absent ossification in vertebral bodies, increased fusion of adjacent lateral vertebral elements, and quantify the extent of dorsal arch widening. Distances between dorsal vertebral arches showed statistically significant increases from L5 through S4 in MMC rats, compared with normal controls.ConclusionHigh‐resolution micro‐CT combined with digital quantification methods is a powerful technique ideally suited for precise assessment of complex congenital skeletal abnormalities such as examined in this rodent model of MMC. Birth Defects Research (Part A) 100:453–462, 2014. © 2014 Wiley Periodicals, Inc.
Thermoluminescence of mercaptoethanol‐capped ZnS:Mn nanoparticles
Authors: Sharma Ravi , Bisen D. P. 
Published: June 2014

ABSTRACTThe thermoluminescence (TL) of nanoparticles has become a matter of keen interest in recent times but is rarely reported. This article reports the synthesis of ZnS:Mn nanocrystals using a chemical route, with mercaptoethanol (ME) as the capping agent. The particle sizes for the nanocrystals were measured by X‐ray diffraction (XRD) and also by studying transmission electron microscopy (TEM) patterns. The particle sizes of the synthesized samples were found to be between 1 and 3 nm. For samples with different concentrations of the capping agent, it was found that the TL intensity of the ZnS:Mn nanoparticles increased as the particle size decreased. A shift in the peak position of the TL glow curve was also seen with decreasing particle size. The TL intensity was found to be maximal for samples with 1.2% of Mn. A change in the peak position was not found for samples with different concentrations of Mn. The half‐width glow peak curve method was used to determine the trap‐depth. The frequency factor of the synthesized samples was also calculated. The stability of the charge carriers in the traps increases with decreasing nanoparticle size. The higher stability may be attributed to the higher surface/volume ratio and also to the increase in the trap‐depth with decreasing particle size. Copyright © 2014 John Wiley & Sons, Ltd.
Interactions between a pollinating seed predator and its host plant: the role of environmental context within a population
Authors: Kula Abigail A. R. , Castillo Dean M. , Dudash Michele R. , Fenster Charles B. 
Published: June 2014

AbstractPlant–insect interactions often are important for plant reproduction, but the outcome of these interactions may vary with environmental context. Pollinating seed predators have positive and negative effects on host plant reproduction, and the interaction outcome is predicted to vary with density or abundance of the partners. We studied the interaction between Silene stellata, an herbaceous perennial, and Hadena ectypa, its specialized pollinating seed predator. Silene stellata is only facultatively dependent upon H. ectypa for pollination because other nocturnal moth co‐pollinators are equally effective at pollen transfer. We hypothesized that for plants without conspecific neighbors, H. ectypa would have higher visitation rates compared to co‐pollinators, and the plants would experience lower levels of H. ectypa pollen deposition. We predicted similar oviposition throughout the study site but greater H. ectypa predation in the area without conspecific neighbors compared to plants embedded in a naturally high density area. We found that H. ectypa had consistently higher visitation than moth co‐pollinators in all host plant contexts. However, H. ectypa pollinator importance declined in areas with low conspecific density because of reduced pollen deposition, resulting in lower seed set. Conversely, oviposition was similar across the study site independent of host plant density. Greater likelihood of very high fruit predation combined with lower pollination by H. ectypa resulted in reduced S. stellata female reproductive success in areas with low conspecific density. Our results demonstrate local context dependency of the outcomes of pollinating seed predator interactions with conspecific host plant density within a population.
Metallo‐β‐lactamases and Their Biomimetic Complexes
Authors: Daumann Lena J. , Schenk Gerhard , Gahan Lawrence R. 
Published: June 2014

AbstractIInvited for the cover of this issue are researchers from the University of Queensland, Australia, and the University of California, Berkeley, USA. The cover image shows a Petri dish with colonies of E. coli – a structure of penicillin is depicted in the middle. Metallo‐β‐lactamase structures bound to the hydrolyzed antibiotic ampicillin and the inhibitor captopril are shown on the left.
Morphological changes of bacterial model membrane vesicles
Authors: Meister Annette , Finger Sebastian , Hause Gerd , Blume Alfred 
Published: June 2014

Unilamellar vesicles frequently serve as model membrane systems to study membrane‐peptide and membrane‐protein interactions. They are formed either from natural lipid extracts that contain complex lipid mixtures, or from synthetic one‐, two‐, or multi‐component lipid mixtures mimicking the lipid composition of biological membranes. Unilamellar vesicles can be prepared by extrusion of aqueous multilamellar phospholipid suspensions and they can have limited stability due to aggregation and fusion processes. We used cryo‐transmission electron microscopy (cryoTEM) to study the morphology of vesicles of phosphatidylethanolamines (PEs), phosphatidylglycerols (PGs), and cardiolipins (CLs) that represent the major lipid components of cytoplasmic membranes of Gram‐negative bacteria. Our results show that single‐component vesicles of PE and PG stored at RT are stable in shape and size for at least 1 wk. In contrast, two‐component vesicles of PE/PG and PE/CL transform into lamellar sheets already several hours after preparation, which is probably due to a compensation of different spontaneous curvatures of PG lipids compared to PE and CL. With this investigation we intend to alert researchers working with model membranes to scrutinize the shape and stability of vesicles before using them in protein‐vesicle interaction studies.Practical applications: Liposomes represent widely‐used model membrane systems that are applied to mimic natural membranes. Usually, these liposomes are composed of one or two lipid components representing the major lipid constituents of the respective natural membrane. Their long‐term shape, aggregation, and fusion stability is an important prerequisite for the study of peptide‐liposome and protein‐liposome interactions, where the binding of peptides or proteins can have serious impacts on the liposomal shape and size. Furthermore, shape and size stability is of outstanding importance for the application of liposomes as drug‐delivery system. We showed that single‐component liposomes composed of the major lipid components of cytoplasmic membranes of Gram‐negative bacteria (PE and PG) are stable in shape and size for at least 1 wk, whereas the corresponding two‐component liposomes become unstable within hours and transform into discs and sheets. This knowledge will be indispensable for future studies on interactions of liposomes with peptides and proteins.Cryo‐transmission electron microscopy is the method of choice to study the size, morphology, and shape stability of liposomes being composed of the phospholipids PE, PG, and CL that represent the major lipid components of cytoplasmic membranes of Gram‐negative bacteria.
Influence of industrial physical refining on tocopherol, chlorophyll and beta‐carotene content in sunflower and rapeseed oil
Authors: Kreps František , Vrbiková Lenka , Schmidt Štefan 
Published: June 2014

The main purpose of this article was to investigate the influence of individual processes in physical refining on tocopherol content in sunflower and rapeseed oils. During refining some chemical parameters, the oxidative stability of oils and some minor compounds such as chlorophyll and beta‐carotene, were determined. Those analytical data with explained chemical backgrounds gave more qualitative overview of what happened to the same lot of oils being processed in a continuous operation. Some processes were compared with a laboratory oil refining. Crude rapeseed oil contained 656 mg/kg of total tocopherols, followed by high oleic sunflower with 373 mg/kg of tocopherols and classic sunflower oil with 332 mg/kg of tocopherols. The most serious refining processes were bleaching and physical deodorization process, the tocopherol losses being 14.9–17.4% and 20.2–27.1%, respectively. In the refined oils, chlorophylls and FFAs were almost completely removed and the oxidative stability increased 2–3 times. Vegetable oil refining process caused relatively great losses of minor compounds but this, in turn, prolonged the shelf life of edible oils.Practical applications: It was proved that refining of sunflower and rapeseed oils in the oil refinery improves their basic chemical parameters. The loss of tocopherols can be minimized by shortening the time and lowering the temperature during the final step of physical refining, but it has to remain within requirements on quality of refined edible oils.The refining processes of sunflower and rapeseed oils lead to 39.0–45.5 % loss of total tocopherol content. The most serious refining processes were bleaching and physical deodorization process, the tocopherol losses being 14.9–17.4 % and 20.2–27.1 %, respectively. Degumming process can caused 6.6–8.4 % decrease of tocopherols in sunflower and rapeseed oil. Most gentle process was winterization of sunflower oils which caused only 2.9–5.8 % tocopherols decrease.
Molecular distillation and characterization of diacylglycerol‐enriched palm olein
Authors: Yeoh Chiou Moi , Phuah Eng Tong , Tang Teck Kim , Siew Wai Lin , Abdullah Luqman Chuah , Choong Thomas Shean Yaw 
Published: June 2014

Lipase‐catalyzed glycerolysis of palm olein was used to produce a mixture of acylglycerols with ∼34‐wt% of DAG. The reaction conditions were 5‐wt% of Lipozyme TLIM at 55°C and 8 h of reaction time. For commercial purposes, it is required to purify the product up to 80‐wt% DAG and with free fatty acids (FFA) content below 0.1‐wt%. A single‐step distillation process was not sufficient to meet this product requirement. Two distinct 2‐step short path distillation approaches were then studied. First scheme involved the removal of TAG by initial distillation step at 250°C, followed by separation of the MAG and FFA from distillate obtained at 180°C during second distillation step at vacuum pressure of 0.1 Pa. Second scheme involved the removal of MAG and FFA in first step at 180°C prior to purification of DAG from residue at 250°C during second distillation step at vacuum achieved up to 0.1 Pa. The results suggested that the first scheme of 2‐step distillation operation was able to achieve 89.9‐wt% of DAG purity without exceeding the limit of 0.1‐wt% of FFA. A final yield of 21.5‐wt% and DAG recovery of 47.8% were obtained using the first scheme. A detailed DAG profile was identified and product characterizations such as fatty acid composition, slip melting point, and solid fat content profile were also investigated. It was observed that purified‐DAG product showed lower iodine value and higher slip melting point than raw material palm olein. The final product had 1134 ± 10 ppm tocols content.Practical applications: This paper has two main practical applications: (i) Enables production of highly purified DAG‐based palm olein via appropriate processing method and processing conditions. (ii) Provide knowledge and understanding of the physicochemical properties of DAG‐enriched palm olein fraction, which is a crucial aspect in food applications.The purpose of this study was to develop an effective distillation process for purification of diacylglycerol (DAG)‐oil. Two distinct 2‐stage short path distillation approaches were proposed and evaluated for their efficacy of operations. It was concluded that first scheme, which involved the removal of TAG in the first distillation stage at 250°C, followed by separation of the MAG and free fatty acid (FFA) from distillate at 180°C in second distillation step, was able to meet product specifications with more than 80‐wt% of DAG purity without exceeding the limit of 0.1‐wt% FFA.