bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the interaction between ginsenoside Rh2 and calf thymus DNA by spectroscopic techniques
Authors: Wu Dudu , Chen Zhi 
Published: February 2015

AbstractThe interaction between ginsenoside Rh2 (G‐Rh2) and calf thymus DNA (ctDNA) was investigated by spectroscopic methods including UV–vis absorption, fluorescence and circular dichroism (CD) spectroscopy, coupled with DNA melting techniques and viscosity measurements. Stern–Volmer plots at different temperatures proved that the quenching mechanism was a static quenching procedure. The thermodynamic parameters, enthalpy change (ΔH) and entropy change (ΔS) were calculated to be –22.83 KJ · mol–1and 15.11 J · mol–1 · K–1by van ’t Hoff equation, suggesting that hydrophobic force might play a major role in the binding of G‐Rh2 to ctDNA. Moreover, the fluorescence quenching study with potassium iodide as quencher indicated that theKSV(Stern–Volmer quenching constant) value for the bound G‐Rh2 with ctDNA was lower than the free G‐Rh2. The relative viscosity of ctDNA increased with the addition of G‐Rh2 and also the ctDNA melting temperature increased in the presence of G‐Rh2. Denatured DNA studies showed that quenching by single‐stranded DNA was less than that by double‐stranded DNA. The observed changes in CD spectra also demonstrated that the intensities of the positive and negative bands decreased with the addition of G‐Rh2. The experimental results suggest that G‐Rh2 molecules bind to ctDNA via an intercalative binding mode. Copyright © 2015 John Wiley & Sons, Ltd.
Myoglobin structure and function: A multiweek biochemistry laboratory project
Authors: Silverstein Todd P. , Kirk Sarah R. , Meyer Scott C. , Holman Karen L. McFarlane 
Published: February 2015

AbstractWe have developed a multiweek laboratory project in which students isolate myoglobin and characterize its structure, function, and redox state. The important laboratory techniques covered in this project include size‐exclusion chromatography, electrophoresis, spectrophotometric titration, and FTIR spectroscopy. Regarding protein structure, students work with computer modeling and visualization of myoglobin and its homologues, after which they spectroscopically characterize its thermal denaturation. Students also study protein function (ligand binding equilibrium) and are instructed on topics in data analysis (calibration curves, nonlinear vs. linear regression). This upper division biochemistry laboratory project is a challenging and rewarding one that not only exposes students to a wide variety of important biochemical laboratory techniques but also ties those techniques together to work with a single readily available and easily characterized protein, myoglobin. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(3):181–188, 2015.
Introducing ethics to chemistry students in a “Research Experiences for Undergraduates” (REU) program
Authors: Hanson Mark J. 
Published: February 2015

AbstractA three‐day ethics seminar introduced ethics to undergraduate environmental chemistry students in the Research Experiences for Undergraduates (REU) program. The seminar helped students become sensitive to and understand the ethical and values dimensions of their work as researchers. It utilized a variety of resources to supplement lectures and class discussion on a variety of issues. Students learned about the relevance of ethics to research, skills in moral reasoning, and the array of ethical issues facing various aspects of scientific research. © 2015 by The International Union of Biochemistry and Molecular Biology, 43(2):76–80, 2015.
Association of dose escalation of octreotide long‐acting release on clinical symptoms and tumor markers and response among patients with neuroendocrine tumors
Authors: Al‐Efraij Khalid , Aljama Mohammed A. , Kennecke Hagen Fritz 
Published: February 2015

AbstractPatients with nonresectable metastatic neuroendocrine tumors (NETs) experience symptoms of hormone hypersecretion including diarrhea, flushing, and bronchoconstriction, which can interfere with quality of life [Anthony and Vinik (2011) Pancreas, 40:987]. Treatment with a long‐acting release formulation of octreotide, a somatostatin analog, can help to alleviate these symptoms. Although high doses of octreotide are often required for adequate symptom control, the relationship between octreotide dose escalation and symptom control in the NET context is not well quantified in the literature. A retrospective chart review was conducted of nonresectable metastatic NET patients who received a dose greater than 30 mg intramuscular octreotide long‐acting formulation (O‐LAR) at any time between January 2005 and December 2011 at the British Columbia Cancer Agency (BCCA). The association between dose escalation of O‐LAR, chromogranin A (CGA), 24‐h urine 5‐hydoxyindoacetate (5‐HIAA), symptom control, and radiological progression was explored. Dose escalation of O‐LAR was associated with improved symptom control in NET patients who were refractory to the standard dose levels. Reduction of serum CGA & 5‐HIAA levels by at least 10% was observed in 31% and 23% respectively. Retrospective review of imaging did not document any reductions in tumor volume. Higher doses of O‐LAR are associated with improved symptom control in NET patients. The variability in tumor marker levels in response to O‐LAR dose escalation may indicate that tumor marker levels may not be an accurate assessment of therapeutic efficacy.
Identification of geographic clustering and regions spared by cutaneous T‐cell lymphoma in Texas using 2 distinct cancer registries
Authors: Litvinov Ivan V. , Tetzlaff Michael T. , Rahme Elham , Habel Youssef , Risser David R. , Gangar Pamela , Jennings Michelle A. , Pehr Kevin , Prieto Victor G. , Sasseville Denis , Duvic Madeleine 
Published: February 2015

BACKGROUNDCutaneous T‐cell lymphomas (CTCLs) (mycosis fungoides and its leukemic variant, Sezary syndrome) are rare malignancies. Reports of the occurrence of mycosis fungoides in married couples and families raise the possibility of an environmental trigger for this cancer. Although it has been suggested that CTCL arises from inappropriate T‐cell stimulation, to the authors' knowledge no preventable trigger has been identified to date.METHODSUsing region, zip code, age, sex, and ethnicity, the authors analyzed the demographic data of 1047 patients from Texas who were seen in a CTCL clinic at The University of Texas MD Anderson Cancer Center during 2000 through 2012 (the MDACC database) and 1990 patients who were recorded in the population‐based Texas Cancer Registry between 1996 and 2010. Subsequently, data from both databases were cross‐analyzed and compared.RESULTSThe current study findings, based on the MDACC database, documented geographic clustering of patients in 3 communities within the Houston metropolitan area, in which CTCL incidence rates were 5 to 20 times higher than the expected population rate. Analysis of the Texas Cancer Registry database defined the CTCL population rate for the state to be 5.8 cases per million individuals per year (95% confidence interval, 5.5‐6.0 per million individuals per year), thus confirming the observations from the MDACC database and further highlighting additional areas of geographic clustering and regions spared from CTCL in Texas.CONCLUSIONSThe current study documented geographic clustering of CTCL cases in Texas and argued for the existence of yet unknown external causes/triggers for this rare malignancy. Cancer 2015;121:1993–2003. © 2015 American Cancer Society.
Application of Polymer Interlayers in Silicon–Carbon Nanotube Heterojunction Solar Cells
Authors: Yu Leping , Tune Daniel D. , Shearer Cameron J. , Shapter Joseph G. 
Published: February 2015

AbstractWe explore the use of polymers as a conducting interlayer within silicon–carbon nanotube heterojunction photovoltaics. Three types of devices have been fabricated and characterized including silicon–carbon nanotube, silicon–conducting polymer and silicon–conducting polymer–carbon nanotube. The conducting polymers studied were polyaniline, poly(3‐hexylthiophene‐2,5‐diyl) and poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate). A thin conducting polymer interlayer significantly improves photovoltaic performance by creating a better depletion layer within the underlying silicon. With the addition of a top antireflection layer, a photovoltaic device, silicon‐poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate)–carbon nanotube–poly(styrene) has been fabricated with a photovoltaic conversion efficiency of 8.7 %.
miR‐181a/b control the assembly of visual circuitry by regulating retinal axon specification and growth
Authors: Carrella Sabrina , D'Agostino Ylenia , Barbato Sara , Huber‐Reggi Sabina P. , Salierno Francesco G. , Manfredi Anna , Neuhauss Stephan C.F. , Banfi Sandro , Conte Ivan 
Published: February 2015

ABSTRACTConnectivity and function of neuronal circuitry require the correct specification and growth of axons and dendrites. Here, we identify the microRNAs miR‐181a and miR‐181b as key regulators of retinal axon specification and growth. Loss of miR‐181a/b in medaka fish (Oryzias latipes) failed to consolidate amacrine cell processes into axons and delayed the growth of retinal ganglion cell (RGC) axons. These alterations were accompanied by defects in visual connectivity and function. We demonstrated that miR‐181a/b exert these actions through negative modulation of MAPK/ERK signaling that in turn leads to RhoA reduction and proper neuritogenesis in both amacrine cells and RGCs via local cytoskeletal rearrangement. Our results identify a new pathway for axon specification and growth unraveling a crucial role of miR‐181a/b in the proper establishment of visual system connectivity and function. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1252–1267, 2015
Seasonality of hydraulic redistribution by trees to grasses and changes in their water‐source use that change tree–grass interactions
Authors: Priyadarshini K. V. R. , Prins Herbert H. T. , de Bie Steven , Heitkönig Ignas M. A. , Woodborne Stephan , Gort Gerrit , Kirkman Kevin , Ludwig Fulco , Dawson Todd E. , de Kroon Hans 
Published: February 2015

AbstractSavanna vegetation is characterized by tree–grass co‐existence that can experience intense water limitation, yet the water relations of these savanna plants are poorly understood. We examined the water sources for trees and grasses in different seasons and investigated the importance of hydraulic redistribution in three tree species inhabiting a semi‐arid savanna in South Africa. We used natural variation in H and O stable isotope composition of source waters to identify the principal water sources for these plants. We conducted an experiment by labelling deep‐soil (2.5‐m depth) with a deuterium tracer. Seasonal differences in the stable isotope composition of water in trees and grasses indicated that there was water‐source use partitioning as well as overlap. Trees and grasses used water from the topsoil after rainfall indicating overlap of water‐source use. All tree species shifted to groundwater or subsoil water use when there was no water in the topsoil indicating partitioning of water use. Grasses always used water from the topsoil. The seasonal changes in water‐source use by trees and grasses indicated possible shifts in tree–grass interactions during different periods of the year. The tracer experiment confirmed hydraulic redistribution in all the three tree species and water transfer to grasses via the topsoil. However, this occurred only in the dry season. Our observations and experimental results indicate the potential for facilitation effects by trees to their understory grasses and show that dry season hydraulic redistribution from trees to grasses could be an important facilitative mechanism maintaining tree–grass co‐existence in savannas. Copyright © 2015 John Wiley & Sons, Ltd.
Mononuclear Iron(II) Dicarbonyls Derived from NNS Ligands – Structural Models Related to a “Pre‐Acyl” Active Site of Mono‐Iron (Hmd) Hydrogenase
Authors: Muthiah Keren A. Thomas , Durgaprasad Gummadi , Xie Zhu‐Lin , Williams Owen M. , Joseph Christopher , Lynch Vincent M. , Rose Michael J. 
Published: February 2015

AbstractWe report the syntheses and characterization of dicarbonyliron complexes derived from tridentate, ortho‐substituted Schiff base pyridine/thioether ligands (RNNS). Metalation reactions of RNNS (R = CH3, OCH3) at low temperature (–78 °C) with [Fe(CO)4(Br)2] afforded the desired complexes [(RNNS)Fe(CO)2Br]Br (2‐COBr, 3‐COBr). Reactions under similar conditions with more sterically demanding ligands [R = quinoline (Q), ClPh] afforded complex salts of the form [(RNNS)Fe(CO)2Br][Fe(CO)3(Br)3] (4‐COFe and 5‐COFe, respectively). Alternatively, the metalation of the RNNS ligands (for all R ≠ H) with [Fe(CO)4(Br)2] in Et2O at room temperature reliably affords the complex species of type [(RNNS)Fe(CO)2Br][Fe(CO)3(Br)3] (2‐COFe, 3‐COFe, 5‐COFe). The metalation reactions of RNNS at only moderately low temperatures (–20 to 0 °C) result in the loss of CO to form the corresponding trigonal‐bipyramidal iron(II) dibromide species of type [(RNNS)FeBr2] (2‐Br, 4‐Br, 5‐Br; μeff ≈ 5.3 μB, S = 2). The IR spectrum of each dicarbonyl cation exhibits two ν(CO) stretches at ≈ 2070 and 2030 cm–1. Low‐temperature 1H NMR spectroscopy measurements of 2‐CO to 5‐CO in CD3CN (–35 to 5 °C) revealed sharp resonances in the diamagnetic region. Under dark conditions, each dicarbonyl species is relatively stable (<10 % loss of CO, 1–2 h). However, photolysis revealed varying extents of photostability (stability rank: R = OMe > Me ≈ Q > ClPh). An examination of the structural parameters reveals that higher photostabilities correlate with shorter Fe–C(O) bond lengths, which are induced by variation of the ortho substituent of the pyridine ring. DFT calculations along the putative photolysis pathway revealed that the bulky ligand substituent (in 5‐CO) destabilizes the monocarbonyl intermediate, and this is a likely explanation for its more rapid rate of CO photodissociation. Relevance to a possible “apo‐active site” of mono‐iron hydrogenase (pre‐acyl formation) is discussed.
CdS/g‐C3N4 Hybrids with Improved Photostability and Visible Light Photocatalytic Activity
Authors: Xu Yao , Zhang Wei‐De 
Published: February 2015

AbstractNovel composite photocatalysts consisting of CdS and graphitic carbon nitride (CdS/g‐C3N4) with different ratios of CdS were prepared. The CdS/g‐C3N4 composite photocatalysts were characterized in detail and their photocatalytic activity was evaluated by using rhodamine B and colorless metronidazole as probes. Compared with pure g‐C3N4, the CdS/g‐C3N4 composite exhibits significantly enhanced photocatalytic activity under visible‐light irradiation. More importantly, g‐C3N4 substantially reinforces the photostability of CdS nanowires even in a nonsacrificial system. The synergistic effect between CdS and g‐C3N4 is found to be primarily responsible for enhancement of the separation of photogenerated electrons and holes, which helps improve the photocatalytic performance. A probable photodegradation process of metronidazole was proposed based on an analysis of the degradation products. This study provides new insight into the preparation of highly efficient and stable sulfide‐based composite photocatalysts and facilitates their application in a number of environmentally sensitive areas.
Carbonylative Synthesis of Phthalimides and Benzoxazinones by Using Phenyl Formate as a Carbon Monoxide Source
Authors: Chavan Sujit P. , Bhanage Bhalchandra M. 
Published: February 2015

AbstractA simple and efficient palladium‐catalyzed carbonylative cyclization of N‐substituted 2‐iodobenzamides and 2‐iodoanilides was investigated for the synthesis of phthalimides and benzoxazinones, respectively, by using phenyl formate as a CO source. The present catalytic protocol circumvents the use of an expensive phosphine ligand as well as solvent in the case of the phthalimide synthesis. Moreover, mild reaction conditions and a tolerance of various functional groups enhance the general applicability of this method.
Nucleophile‐Selective Cross‐Coupling Reactions with Vinyl and Alkynyl Bromides on a Dinucleophilic Aromatic Substrate
Authors: He Lu‐Ying , Schulz‐Senft Mathias , Thiedemann Birk , Linshoeft Julian , Gates Paul J. , Staubitz Anne 
Published: February 2015

AbstractA nucleophile‐selective cross‐coupling reaction on an aromatic compound bearing two metal groups, Bpin and SnMe3, has been developed. Previously, only aryl bromides and iodides could be used as electrophilic components, but in this work, the scope could be extended to vinyl and alkynyl bromides as electrophiles. This means that the roles typical in Sonogashira couplings or Heck reactions of the aromatic ring as the dielectrophile coupling to vinyl and alkynyl metal species are reversed, which presents a new tool for organic synthesis. The first nucleophilic site to react is the stannyl group, and subsequently, a Suzuki–Miyaura cross‐coupling reaction can take place on the same molecule.
A broad cocktail of environmental pollutants found in eggs of three seabird species from remote colonies in Norway
Authors: Huber Sandra , Warner Nicholas A. , Nygård Torgeir , Remberger Mikael , Harju Mikael , Uggerud Hilde T. , Kaj Lennart , Hanssen Linda 
Published: February 2015

Abstract

Eggs of 3 seabird species, common eider (Somateria mollisima), European shag (Phalacrocorax aristotelis aristotelis), and European herring gull (Larus argentatus), were surveyed for a broad range of legacy and emerging pollutants to assess chemical mixture exposure profiles of seabirds from the Norwegian marine environment. In total, 201 chemical substances were targeted for analysis ranging from metals, organotin compounds, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and associated metabolites, chlorinated paraffins, chlorinated and nonchlorinated organic pesticides, per- and polyfluoroalkyl substances (PFAS), dechlorane plus, octachlorostyrene, brominated flame retardants (BFRs), organophosphorous compounds, brominated and alkyl phenols, cyclic siloxanes, and phthalates. Of the chemicals targeted, 149 substances were found above the detection limits, with metals dominating the contaminant profile and comprising 60% of the total contaminant load. Polychlorinated biphenyls, pesticides, organophosphorous compounds, and PFAS were the dominant contaminant classes of organic pollutants found within the seabird species, with the highest loads occurring in herring gulls, followed by shag, and common eider. New generation pollutants (e.g., PFAS, organophosphorous compounds, and alkylphenols) were detected at similar or higher concentrations than the legacy persistent organic pollutants (POPs). Time trends of reported concentrations of legacy POPs appear to have decreased in recent decades from the Norwegian coastal environment. Concentrations of detected pollutants do not appear to have a negative effect on seabird population development within the sampling area. Additional stress caused by pollutants, however, may affect seabird health more at the individual level. Environ Toxicol Chem 2015;34:1296–1308. © 2015 SETAC
Cadmium inhibits the vitellogenesis of freshwater crab Sinopotamon henanense
Authors: Yang Jian , Liu Dongmei , Dahms Hans-Uwe , Wang Lan 
Published: February 2015

Abstract

Cadmium (Cd) may pose risks to freshwater organisms, including crabs that live at the interface of sediments and water column all year round. One of the major changes that occur during oocyte maturation of crabs is the production of vitellin. In the present study, the authors investigated the effects of Cd on oocyte size, vitellin level, and vitellogenin (Vtg) messenger RNA (mRNA) expression in the ovary of the freshwater crab Sinopotamon henanense. The authors studied the impacts of Cd on carbohydrate as well as on the protein metabolism, metallothionein, glutathione (GSH) synthesis, energy-related parameters, and mRNA expression of genes involved in energy metabolism. After Cd treatment, vitellin concentration, Vtg mRNA expression, and oocyte diameter decreased. Less carbohydrate and enhanced protein catabolism were found in the ovary. Adenosine triphosphate to adenosine diphosphate (ATP:ADP) ratios, reduced nicotinamide adenine dinucleotide (NADH) to oxidized nicotinamide adenine dinucleotide (NAD+) ratios, mitochondrial membrane potential, and energy production-related mRNA expressions increased in the ovary after 10 d Cd treatment and decreased after 20 d. Metallothionein and GSH synthesis were up-regulated after 10 d on Cd exposure. Moreover, Cd caused a time-dependent up-regulation of malondialdehyde. The authors' findings show significant effects of Cd on vitellogenesis, which suggests that Cd slows down vitellogenesis in S. henanense because of excessive energy consumption and an activated defense system. Environ Toxicol Chem 2015;34:1609–1616. © 2015 SETAC
Fast and upper bounded Fano decoding algorithm: queuing analysis
Authors: Darabkh Khalid A. 
Published: February 2015

AbstractIn computer networking, having limited buffer size is one of the vital causes of splitting the messages into smaller frames to be then transmitted over the network. Increasing the buffer size will not improve the case much but rather it is likely to degrade the performance of the system if it is not investigated properly. On the other hand, frames' retransmissions, as a result of frames being corrupted or dropped, need to be avoided as much as possible because of possible network congestion. To investigate the problem of undesired retransmissions, this paper addresses the use of convolutional codes utilising variable complexity decoding algorithms, such as the Fano algorithm, which mainly aim to mitigate frames' retransmissions caused by frames' corruption. It is noteworthy to mention that the rapid growth of wireless technologies has attracted everybody's attention. As wireless technology evolves, new decoding algorithms are emerging to demonstrate designs with variable power consumptions. Hence, in this paper, we propose a novel queuing model that describes not only frame arriving and departing processes after getting decoded according to how worse the channel condition is or what is the remaining system power but also a decoder with a double speed compared with what is best scrutinised in the literature. Moreover, in our buffering model, we can reduce the number of frames being dropped because of insufficient buffer size, and unwanted retransmissions owing to long frame waiting time, by virtue of bestowing larger buffer size, through our derived closed‐form expression that represents the expected number of awaiting frames in the buffers of Fano decoders parameterised by channel status, decoding threshold and frame arriving probability. As far as the system occupancy is concerned and over what have been previously proposed, our analytical results show impressive improvements. As such, through our proposed queuing model, the required decoder's buffer is substantially smaller of what that obtained by a prior model, considering the same networking parameters, which prompts decreasing the average frame waiting time. Copyright © 2015 John Wiley & Sons, Ltd.