bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cellular and Molecular Basis of Liver Development
Authors: Shin Donghun , Monga Satdarshan Pal Singh 
Published: April 2013

AbstractLiver is a prime organ responsible for synthesis, metabolism, and detoxification. The organ is endodermal in origin and its development is regulated by temporal, complex, and finely balanced cellular and molecular interactions that dictate its origin, growth, and maturation. We discuss the relevance of endoderm patterning, which truly is the first step toward mapping of domains that will give rise to specific organs. Once foregut patterning is completed, certain cells within the foregut endoderm gain competence in the form of expression of certain transcription factors that allow them to respond to certain inductive signals. Hepatic specification is then a result of such inductive signals, which often emanate from the surrounding mesenchyme. During hepatic specification bipotential hepatic stem cells or hepatoblasts become apparent and undergo expansion, which results in a visible liver primordium during the stage of hepatic morphogenesis. Hepatoblasts next differentiate into either hepatocytes or cholangiocytes. The expansion and differentiation is regulated by cellular and molecular interactions between hepatoblasts and mesenchymal cells including sinusoidal endothelial cells, stellate cells, and also innate hematopoietic elements. Further maturation of hepatocytes and cholangiocytes continues during late hepatic development as a function of various growth factors. At this time, liver gains architectural novelty in the form of zonality and at cellular level acquires polarity. A comprehensive elucidation of such finely tuned developmental cues have been the basis of transdifferentiation of various types of stem cells to hepatocyte‐like cells for purposes of understanding health and disease and for therapeutic applications. © 2013 American Physiological Society.Compr Physiol3:799‐815, 2013.
Label‐Free Analysis of Cellular Biochemistry by Raman Spectroscopy and Microscopy
Authors: Schie Iwan W. , Huser Thomas 
Published: April 2013

AbstractWe review the biomedical applications of Raman spectroscopy at the single cell and tissue level. Raman scattering is the inelastic scattering of light by molecular bonds resulting in a wealth of spectral bands, which enable the identification of biological materials and the nondestructive analysis of dynamic changes in their biochemistry. We briefly review the basics behind highly sensitive Raman spectroscopy and highlight recent applications to biomedical research. We discuss advanced chemometrics methods that are utilized to analyze Raman spectral data and which permit one, for example, to distinguish between normal and diseased cells or which enable one to follow the differentiation of stem cells without perturbing the cellular biochemistry. We also discuss advanced coherent Raman scattering techniques, such as coherent anti‐Stokes Raman scattering and stimulated Raman scattering, which allow for the molecularly specific imaging of cells, tissues, and entire organismsin vitroandin vivo. © 2013 American Physiological Society.Compr Physiol3:941‐956, 2013.
Pathways of introduction of the invasive aquatic plant Cabomba caroliniana
Authors: McCracken Andrée , Bainard Jillian D. , Miller Michelle C. , Husband Brian C. 
Published: April 2013

AbstractThe pathway and frequency of species' introductions can affect the extent, impact, and management of biological invasions. Here, we examine the pathway of introduction of the aquatic plant Cabomba caroliniana (fanwort) into Canada and the northern United States using plastid DNA sequence (intergenic spacers atpF‐atpH, trnH‐psbA, and trnL‐trnF) and DNA content analyses. We test the hypothesis that the spread of fanwort is a result of commercial trade by comparing a Canadian population (Kasshabog Lake, ON) to native populations from southern U.S., introduced populations in northern U.S., and plants from commercial retailers. Thirteen plastid haplotypes were identified throughout North America, including one dominant haplotype, which was present in all C. caroliniana populations. Several rare haplotypes were used to infer shared colonization history. In particular, the Canadian population shared two rare alleles with a population from Massachusetts, suggesting range expansion of C. caroliniana from the northern U.S. However, the possibility of a commercial introduction cannot be excluded, as common alleles were shared between the Canadian population and both commercial and southern U.S. sources. Variation in C. caroliniana genome size was bimodal and populations were classified into “high” and “low” categories. The Canadian population had DNA contents similar to several northern U.S. populations (low DNA content). This may provide additional support for range expansion from these introduced populations rather than from commercial sources or populations in the southern U.S., which had high DNA content.
Influence of lipids on the properties of solid lipid nanoparticles from microemulsion technique
Authors: Boonme Prapaporn , Souto Eliana B. , Wuttisantikul Norasak , Jongjit Tarntep , Pichayakorn Wiwat 
Published: April 2013

Solid lipid nanoparticles (SLN) are colloidal lipid carriers widely employed as efficient drug delivery systems. In this report, SLN were produced by microemulsion technique, and the influence of lipid composition on the physical properties of SLN was evaluated. Lipids with different molecular structures in carbon number of the fatty acid residue and their polarity were selected (i.e., glyceryl trimyristate, glyceryl tripalmitate, glyceryl tristearate, stearic acid, and glyceryl monostearate). A warm oil‐in‐water microemulsion containing 7% lipid, 30% water, and 63% surfactant mixture (polysorbate 80:1‐butanol 4:1) was prepared by simple mixing at 60°C, following its dilution in cold water at various ratios at constant stirring. The obtained SLN were analyzed for appearance, particle size, zeta potential, and sedimentation rate. The chemical structure of the selected lipids affected both the microemulsion formation and the physical characteristics of SLN. From the obtained results, a dilution ratio of 1:50 was selected for the production of SLN composed of glyceryl trimyristate as solid lipid matrix. The obtained particles were of 154.9 ± 0.7 nm mean particle size, with a polydispersity index (PI) of 0.274 and zeta potential of −7.46 ± 0.68 mV.Practical applications: The methodology presented here describes the application of microemulsion technique on processing different lipid compositions, to develop and produce an optimal SLN formulation using pseudoternary phase diagrams. Microemulsion technique is well‐known for preparation SLN by adding a warm oil‐in‐water microemulsion, which can be spontaneously formed, when diluted in a large volume of cold water. The data presented in this paper show that the molecular structures of lipids influenced both the microemulsion formation and the physical characteristics of the resulting SLN. The optimal SLN formulation could be developed.
Screening of antioxidants as stabilisers for Jatropha curcas L. oil
Authors: Subroto Erna , Manurung Robert , Heeres Hero Jan , Broekhuis Antonius Augustinus 
Published: April 2013

AbstractThe effect of antioxidants on the oxidation stability of oils extracted from Jatropha curcas seeds was measured by the accelerated oxidation test specified in EN 14112 using commercial Rancimat 873 equipment. To find the appropriate antioxidant for jatropha oil, fourteen different antioxidants were screened at concentrations of 500 and 1000 ppm. Pyrogallol (PY) and propyl gallate (PG) significantly improved the oxidative stability of jatropha oil and PY was further studied at concentrations of 50–1000 ppm. Even at concentrations as low as 50 ppm, PY was found to fulfill the specifications set by the DIN 51605 norm for plant oil as biofuels. Mixtures of antioxidants were tested at concentrations varying between 100 and 1000 ppm, showing a synergistic effect for the combination of PY and N,N′‐di‐sec‐butyl‐p‐phenylenediamine at all concentrations and ratios tested. It further was found that the quality, i.e. the history of the oil in terms of processing, age and storage conditions, strongly affects the performance of PY as the antioxidant. PY in particular improved the oxidative stability of oxidized and highly acidic oils. PY was found to be a good antioxidant for both jatropha oil and the derived biodiesel.Practical applications: Jatropha oil is one of many potential triglyceride feedstocks suitable for the production of biofuel or other consumer products. Finding the best antioxidant for this particular resource is important since the resistance to oxidative degradation depends on the chemical structure of the triglyceride. Pyrogallol was found to be the preferred antioxidant with beneficial results found for oxidized and, as a result, highly acidic oils. The results of this study are useful for companies involved in jatropha oil‐derived products such as biodiesel, lubricants or other non‐food applications.
Associations of RBP4 with lipid metabolism and renal function in diabetes mellitus
Authors: Junjun Wang , Jia Wu , Jiaxi Song , Dongmei Niu , Yonghui Shi , Fang Zheng , Xin Zhou 
Published: April 2013

AbstractTo investigate the plasma retinol‐binding protein 4 (RBP4), small dense low‐density lipoprotein cholesterol (sdLDL‐C), oxidized low‐density lipoprotein (ox‐LDL) levels and to evaluate the associations of RBP4 with abnormal lipid metabolism and renal dysfunction in type 2 diabetes mellitus (T2DM) patients, we determined RBP4, sdLDL‐C, ox‐LDL levels and renal parameters in 120 T2DM patients with or without nephropathy and 70 controls. The correlation analysis and multiple linear regression analysis were performed. Compared with controls, the RBP4 and sdLDL‐C levels were found significantly increased only in diabetic nephropathy (DN) patients and ox‐LDL levels were elevated in both groups of T2DM patients. The RBP4 levels were positively correlated with sdLDL‐C, ox‐LDL, and negatively with estimated glomerular filtration rate (eGFR) in all the T2DM patients. Multiple linear regression analysis showed that sdLDL‐C and eGFR were the independent predictors of RBP4 levels, and RBP4 were one of the independent determinants for sdLDL‐C and ox‐LDL levels in T2DM patients, respectively. In conclusion, plasma RBP4, sdLDL‐C, ox‐LDL levels were significantly increased in DN patients. Circulating RBP4 may be associated with abnormal lipid metabolism and renal dysfunction, and considered as a biomarker of cardiovascular disease and renal function in T2DM patients.Practical applications: The findings in the present study support the hypothesis that circulating RBP4 not only plays an important role in lipid metabolism abnormalities of atherosclerosis, contributing to the increased risk of CVD, but also could reflect renal dysfunction and be associated with the severity of nephropathy in T2DM patients. Therefore, the clinical monitoring of plasma RBP4 level as well as its dynamic changes may possess distinctly clinical value for assessments of renal function and CVD risk in T2DM patients. These findings may contribute to the further understanding of the pathogenic role of circulating RBP4 in proatherogenic dyslipidemia and nephropathy in T2DM.
Production of lipids and docosahexasaenoic acid (DHA) by a native Thraustochytrium strain
Authors: Shene Carolina , Leyton Allison , Rubilar Mónica , Pinelo Manuel , Acevedo Francisca , Morales Eduardo 
Published: April 2013

AbstractProduction of docosahexasaenoic acid (DHA) by a native Labyrinthulomycetes strain, Thraustochytriidae sp. TN5, whose growth characteristics present some differences to related strains, was scaled from shaken flask to a laboratory fermentor. The effect of the growth medium composition and growth conditions for (i) biomass production, (ii) lipid content of the biomass, and (iii) DHA content in the lipids was determined. Taguchi's design of experiments was used to study the influence of two discrete – carbon and nitrogen sources – and six continuous – concentrations of the carbon and nitrogen sources, yeast extract and artificial seawater, incubation temperature, and time‐ factors on the three mentioned variables. In the flask experiments the lipidic content in the biomass (25.2% w/w) and DHA concentration (0.48 g/L) were the highest at the following conditions: maltose 20 g/L, sodium glutamate 2.4 g/L, yeast extract 6 g/L, 72 h, 25°C, and artificial seawater 30% v/v; under these conditions biomass concentration was 5.1 g/L. Fed‐batch allowed to increase biomass concentration to 14 g/L. The lipidic fraction of Thraustochytriidae sp. TN5 biomass in the repeated batches was found between 16.2 and 34.8% w/w. Under this growth condition lipids and DHA productivities were 50 and 23 mg/(L h), respectively.Practical applications: Consumption of long chain‐polyunsaturated fatty acids (LC‐PUFA) belonging to the omega‐3 family such as DHA has several positive effects on human and animal health. However, natural sources are restricted to cold‐water fish and their oils. Marine protists are also good candidates for the production of microbial DHA. For evaluating the potential of new strains the effect of the growth medium composition, growth conditions, and cultivation mode on DHA productivity has to be determined. In this work the production of DHA by a native Labyrinthulomycetes strain was scaled from shaken flask to a laboratory fermentor with the aid of Taguchi's methodology, process in which biomass concentration, lipid content in the biomass, and DHA content in the lipids were increased.
The Role of the Chiral cis‐1,3‐Disubstituted 2,2‐Dimethylcyclobutane Motif in the Conformational Bias of Several Types of γ‐Peptides
Authors: Aguilera Jordi , Cobos Juan A. , Gutiérrez‐Abad Raquel , Acosta Carles , Nolis Pau , Illa Ona , Ortuño Rosa M. 
Published: April 2013

AbstractThree series of new γ‐peptides have been synthesized by starting from conveniently protected cis‐3‐amino‐2,2‐dimethylcyclobutane‐1‐carboxylic acid derivatives. The first series is constructed with only one enantiomer of this γ‐amino acid, whereas in the second one both enantiomeric cyclobutane residues are joined in alternating fashion. The high degrees of rigidity in these γ‐peptides induce the adoption of extended but sterically constrained conformations in both cases. The third series is the product of alternation of a cyclobutane residue with linear γ‐aminobutyric acid (GABA). Conformational bias in these three systems accounts for the cyclobutane being a major disrupting factor to the formation of strong intramolecular hydrogen bonds, leading to extended conformations. In contrast, investigation of cyclobutane/GABA hybrid γ‐peptides of a fourth series, in which the carbocyclic moiety is not a part of the polyamide skeleton but acts as a chiral polyfunctional platform, reveals that these peptides are able to produce intramolecular hydrogen bonds leading to well defined folded conformations.
Polymer‐Supported Stereoselective Synthesis of (1S,5S)‐6‐Oxa‐3,8‐diazabicyclo[3.2.1]octanes
Authors: Schütznerová Eva , Oliver Allen G. , Zajíček Jaroslav , Krchňák Viktor 
Published: April 2013

AbstractWe describe a polymer‐supported stereoselective synthesis of the (1S,5S)‐6‐oxa‐3,8‐diazabicyclo[3.2.1]octane‐bridged scaffold by tandem iminium ion cyclization/nucleophilic addition reactions. A series of resin‐bound acyclic intermediates bearing different substituents were prepared, and the scope and limitations of the chemical route leading to the bridged scaffold were evaluated. The Thr‐derived bridged scaffold was found to be substantially more stable in acid than the Ser‐derived scaffold, which was partially transformed into dihydropyrazinones. Substitution at the iminium‐forming nitrogen was critical for acid stability, and the N‐arylsulfonamides with electron‐withdrawing groups yielded the highest purity of the crude products prepared by acid‐mediated cleavage. The acid‐labile target compounds were synthesized by nucleophile‐mediated cleavage from the esterified Wang resin and cyclization in formic acid.
Unified Azoline and Azole Syntheses by Optimized Aza‐Wittig Chemistry
Authors: Loos Patrick , Ronco Cyril , Riedrich Matthias , Arndt Hans‐Dieter 
Published: April 2013

AbstractIntramolecular aza‐Wittig ring closures were applied to synthesize thiazolines, oxazolines, and imidazolines from β‐azido thioester, ester, and amide precursors. The cyclization precursors were obtained from amino acid derivatives. Optimized conditions for diazo transfer with a fast rate and racemization suppression, (thio)esterification, and amide coupling reactions are described. The ring closure reaction can be executed with PPh3 under neutral conditions and was found to be highly chemoselective for five‐membered rings. If amide groups were activated with tosyl groups, smooth intramolecular ring closure of iminophosphoranes furnished enantiopure imidazoline products with position‐specific tosyl protection. This aza‐Wittig‐based azoline synthesis was then extended to double azoline ring closures to furnish catenated azoline building blocks common to peptide natural product building blocks and their analogues.
Stereoselective Synthesis of Benzoxepines through Tandem Alkylation/Michael Addition to Vinylogous Carbonates
Authors: Gharpure Santosh J. , Reddy S. Raja Bhushan 
Published: April 2013

AbstractA tandem SN2 alkylation/Michael addition to vinylogous carbonates based approach for the stereoselective synthesis of benzoxepines is developed. The stereoselectivity improves with an increase in the steric bulk of the substituents. The method is extended to the synthesis of benzopyranoxepines and benzoxepinopyridines with angular substituents.
Toll‐like receptor 7 stimulates production of specialized pro‐resolving lipid mediators and promotes resolution of airway inflammation
Authors: Koltsida Ourania , Karamnov Sergey , Pyrillou Katerina , Vickery Thad , Chairakaki Aikaterini‐Dimitra , Tamvakopoulos Constantin , Sideras Paschalis , Serhan Charles N. , Andreakos Evangelos 
Published: April 2013

AbstractAlthough specialized pro‐resolving mediators (SPMs) biosynthesized from polyunsaturated fatty acids are critical for the resolution of acute inflammation, the molecules and pathways that induce their production remain elusive. Here, we show that TLR7, a receptor recognizing viral ssRNA and damaged self‐RNA, mobilizes the docosahexaenoic acid (DHA)‐derived biosynthetic pathways that lead to the generation of D‐series SPMs. In mouse macrophages and human monocytes, TLR7 activation triggered production of DHA‐derived monohydroxy metabolome markers and generation of protectin D1 (PD1) and resolvin D1 (RvD1). In mouse allergic airway inflammation, TLR7 activation enhanced production of DHA‐derived SPMs including PD1 and accelerated the catabasis of Th2‐mediated inflammation. D‐series SPMs were critical for TLR7‐mediated resolution of airway inflammation as this effect was lost in Alox15−/− mice, while resolution was enhanced after local administration of PD1 or RvD1. Together, our findings reveal a new previously unsuspected role of TLR7 in the generation of D‐series SPMs and the resolution of allergic airway inflammation. They also identify TLR stimulation as a new approach to drive SPMs and resolution of inflammatory diseases.
On the modeling and simulation of a laser‐induced cavitation bubble
Authors: Zein Ali , Hantke Maren , Warnecke Gerald 
Published: April 2013

SUMMARYSingle cavitation bubbles exhibit severe modeling and simulation difficulties. This is due to the small scales of time and space as well as due to the involvement of different phenomena in the dynamics of the bubble. For example, the compressibility, phase transition, and the existence of a noncondensable gas inside the bubble have strong effects on the dynamics of the bubble. Moreover, the collapse of the bubble involves the occurrence of critical conditions for the pressure and temperature. This adds extra difficulties to the choice of equations of state. Even though several models and simulations have been used to study the dynamics of the cavitation bubbles, many details are still not clearly accounted for.Here, we present a numerical investigation for the collapse and rebound of a laser‐induced cavitation bubble in liquid water. The compressibility of the liquid and vapor are involved. In addition, great focus is devoted to study the effects of phase transition and the existence of a noncondensable gas on the dynamics of the collapsing bubble. If the bubble contains vapor only, we use the six‐equation model for two‐phase flows that was modified in our previous work [A. Zein, M. Hantke, and G. Warnecke,J. Comput. Phys., 229(8):2964‐2998, 2010]. This model is an extension to the six‐equation model with a single velocity of Kapilaet al.(Phys. Fluid, 13:3002‐3024, 2001) taking into account the heat and mass transfer.To study the effect of a noncondensable gas inside the bubble, we add a third phase to the original model. In this case, the phase transition is considered only at interfaces that separate the liquid and its vapor. The stiffened gas equations of state are used as closure relations. We use our own method to determine the parameters to obtain reasonable equations of state for a wide range of temperatures and make them suitable for the phase transition effects. We compare our results with experimental ones. Also our results confirm some expected physical phenomena. Copyright © 2013 John Wiley & Sons, Ltd.
Coupling of Hawaiian volcanoes only during overpressure condition
Authors: Shirzaei Manoochehr , Walter Thomas R. , Bürgmann Roland 
Published: April 2013

AbstractMauna Loa and Kilauea volcanoes, Hawaii, are thought to be coupled by pore pressure diffusion through an asthenospheric melt layer. However, abundant observations of independent activity of these volcanoes suggest a more complicated relationship. Here we analyze surface deformation data, deep seismicity and gas measurements, to reveal strong coupling of these volcanoes between 2003 and 2008. In early 2005, we find a shift from anticorrelation to correlation of magma‐chamber inflation. The shift is preceded by a seismic swarm in the mantle beneath Mauna Loa and accompanied by a large silent slip event beneath the south flank of Kilauea. This suggests that these volcanoes are coupled during mantle‐driven surges and that the 2005 silent slip event was triggered by accelerated magma supply at Kilauea.