bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasmonic Enhancement of a Photocycloreversion Reaction of a Diarylethene Derivative Using Individually Dispersed Silver Nanoparticles
Authors: Nishi Hiroyasu , Asahi Tsuyoshi , Kobatake Seiya
Published: September 2012

The fabrication of silver nanoparticles covered with polymers with a well‐defined core–shell structure and the quantitative evaluation of the plasmonic enhancement effect on a photochemical reaction in the vicinity of these silver nanoparticles individually dispersed in a medium are described. The photocycloreversion reaction of a diarylethene polymer in the vicinity of silver nanoparticles was enhanced by 2–6 times relative to the reaction without the nanoparticles. The promotion of the photocycloreversion reaction is due to enhancement of the electromagnetic field near the surface of the silver core.
Three Modes of Proton Transfer in One Chromophore: Photoinduced Tautomerization in 2‐(1H‐Pyrazol‐5‐yl)Pyridines, Their Dimers and Alcohol Complexes
Authors: Vetokhina Volha , Dobek Krzysztof , Kijak Michał , Kamińska Izabela I. , Muller Keven , Thiel Werner R. , Waluk Jacek , Herbich Jerzy
Published: September 2012

Studies of 2‐(1H‐pyrazol‐5‐yl)pyridine (PPP) and its derivatives 2‐(4‐methyl‐1H‐pyrazol‐5‐yl)pyridine (MPP) and 2‐(3‐bromo‐1H‐pyrazol‐5‐yl)pyridine (BPP) by stationary and time‐resolved UV/Vis spectroscopic methods, and quantum chemical computations show that this class of compounds provides a rare example of molecules that exhibit three types of photoreactions: 1) excited‐state intramolecular proton transfer (ESIPT) in the syn form of MPP, 2) excited‐state intermolecular double‐proton transfer (ESDPT) in the dimers of PPP in nonpolar media, as well as 3) solvent‐assisted double‐proton transfer in hydrogen‐bonded 1:1 complexes of PPP and MPP with alcoholic partners. The excited‐state processes are manifested by the appearance of a dual luminescence and a bimodal irreversible kinetic coupling of the two fluorescence bands. Ground‐state syn–anti equilibria are detected and discussed. The fraction of the higher‐energy anti form varies for different derivatives and is strongly dependent on the solvent polarity and hydrogen‐bond donor or acceptor abilities.
Cognitive Bibliotherapy for Mild Depressive Symptomatology: Randomized Clinical Trial of Efficacy and Mechanisms of Change
Authors: Moldovan Ramona , Cobeanu Oana , David Daniel
Published: September 2012

Background

It has been increasingly recognized that subthreshold depression is associated with considerable personal, social and economic costs. However, there is no accepted definition or clear‐cut treatment for subthreshold depression. Cognitive bibliotherapy is a promising approach, but further research is necessary in order to assess its clinical efficacy and key mechanisms of change.

Aim

This study aimed to investigate the efficacy of bibliotherapy for subthreshold depression and test whether maladaptive cognitions mediate the effects of bibliotherapy on depressive symptoms.

Method

A total of 96 young adults with subthreshold depression were randomized in one of the following treatment conditions: immediate treatment, delayed treatment, placebo and no treatment. The main outcome was represented by depressive symptoms assessed before, during and immediately after the treatment, as well as at 3‐month follow‐up. Automatic thoughts, dysfunctional attitudes and irrational beliefs were also assessed throughout the study, and we investigated their involvement as mediators of bibliotherapy effects on depressive symptoms.

Results

The results indicated that cognitive bibliotherapy resulted in statistically and clinically significant changes both in depressive symptoms and cognitions, which were maintained at follow‐up. In contrast, placebo was only associated with a temporary decrease in depressive symptoms, without significant cognitive changes. No changes in symptoms or cognitions were found in the delayed treatment and no treatment groups. We also found that automatic thoughts significantly mediated the effect of bibliotherapy on depressive symptoms.

Conclusion

This study provided compelling evidence for the efficacy of cognitive bibliotherapy in subthreshold depression and showed that changes in automatic thoughts mediated the effect of bibliotherapy on depressive symptoms. Copyright © 2012 John Wiley & Sons, Ltd.

Key Practitioner Message

Cognitive bibliotherapy is an effective treatment of subthreshold depression.

Changing automatic thoughts is important, as they mediate the bibliotherapy effect on depressive symptoms.

Cognitive bibliotherapy is a potential alternative or adjunct to psychotherapy for mildly depressed adults.
Dislocation‐related photoluminescence imaging of mc‐Si wafers at room temperature
Authors: Mankovics D. , Schmid R. P. , Arguirov T. , Kittler M.
Published: September 2012

We report on a method for fast detection of defect rich areas in multicrystalline silicon solar wafers. It is based on photoluminescence imaging of the whole wafers and detects both the band‐to‐band radiation as well as the dislocation specific radiation D1. To illustrate the capabilities of the method we examined 5.0 × 5.0 cm2 wafer pieces in different stages of their processing. The achieved resolution of the D1 images was ∼120 μm, within a total recording time of 550 ms.
Controlling Surface Enrichment in Polymeric Hole Extraction Layers to Achieve High‐Efficiency Organic Photovoltaic Cells
Authors: Kim Dong‐Hun , Lim Kyung‐Geun , Park Jong Hyeok , Lee Tae‐Woo
Published: September 2012

Hole extraction in organic photovoltaic cells (OPVs) can be modulated by a surface‐enriched layer formed on top of the conducting polymer‐based hole extraction layer (HEL). This tunes the surface work function of the HEL to better align with the ionization potential of the polymeric photoactive layer. Results show noticeable improvement in device power conversion efficiencies (PCEs) in OPVs. We achieved a 6.1 % PCE from the OPV by optimizing the surface‐enriched layer.
Cramer–Rao bound based mean‐squared error and throughput analysis of superimposed pilots for semi‐blind multiple‐input multiple‐output wireless channel estimation
Authors: Jagannatham Aditya K. , Rao Bhaskar D.
Published: September 2012

This work presents a study of the mean‐squared error (MSE) and throughput performance of superimposed pilots (SP) for the estimation of a multiple‐input multiple‐output (MIMO) wireless channel. The Cramer–Rao bound (CRB) is derived for SP based estimation of the MIMO channel matrix. Employing the CRB analysis, it is proved that the asymptotic MSE bound is potentially 3 dB lower than the MSE performance of the existing SP mean based estimation (SPME) schemes. Motivated by this observation, a novel SP semi‐blind scheme is presented for MIMO channel estimation. This scheme asymptotically achieves the CRB and hence has a lower MSE of estimation when compared with SPME schemes. We also derive closed form expressions for the optimal source‐pilot power allocation in SP by maximizing the post‐processing signal‐to‐noise power ratio at the receiver. In the final part, a new result is presented for the worst‐case capacity of a communication channel with correlated information symbols and noise. This framework is employed to quantify the throughput performance of SP and also to demonstrate the bandwidth efficiency of SP compared with that of a conventional pilot based system. Copyright © 2012 John Wiley & Sons, Ltd.
Glycerol hydrogenolysis into propanediols using in situ generated hydrogen – A critical review
Authors: Martin Andreas , Armbruster Udo , Gandarias Inaki , Arias Pedro Luis
Published: September 2012

The rise in chemical transesterification of plant triglycerides towards biodiesel is unbowed and thus the available amount of glycerol is still increasing. The produced amount overruns the chemically used portion. Various ways to convert glycerol have been shown recently to yield attractive intermediates and final products. One of the options of future chemical utilisation of glycerol might be its conversion to propanediols (1,2‐PDO (propylene glycol), 1,3‐PDO (trimethylene glycol)) by hydrogenolysis. 1,2‐PDO finds various applications in chemical industries; 1,3‐PDO is mainly used for the manufacture of polymers. A synthesis route via glycerol might substitute present industrial syntheses using for example propylene oxide. Such an alternative synthesis route might run in the presence of externally fed hydrogen or by use of in situ generated hydrogen that can be supplied for example by glycerol aqueous phase reforming (APR) and/or catalytic transfer hydrogenation (CTH) using hydrogen donor molecules. A very attractive approach seems to be the use of formic acid as hydrogen donor for CTH because only carbon dioxide is liberated as a by‐product. This paper summarises most significant reports of the last decade, dealing with the production of PDOs via glycerol hydrogenolysis by in situ generated hydrogen.
Electrophilic Cyclization and Ring‐Closing Metathesis as Key Steps in the Synthesis of a 12‐Membered Cyclic Enediyne
Authors: Danilkina Natalia , Nieger Martin , Selivanov Stanislav , Bräse Stefan , Balova Irina
Published: September 2012

For the first time, electrophilic cyclization and ring‐closing metathesis were used as key steps in the synthesis of a macrocyclic enediyne system, which allowed a 12‐membered dienediyne containing a thiophene‐fused ring to be obtained. The macrocycle synthesized represents a class of compounds that possess planar chirality and exists in the solid state as two enantiomers, whereas in solution the rate of interconversion is rapid as a result of unhindered switching of the double bond through the macrocycle.
Nickel‐Catalyzed Indium(I)‐Mediated syn‐Selective Propargylation of Aldehydes
Authors: Hirashita Tsunehisa , Suzuki Yuuki , Tsuji Hiromitsu , Sato Yoshiki , Naito Kojiro , Araki Shuki
Published: September 2012

Low‐valent indium(I)‐mediated nickel‐catalyzed propargylation of aldehydes is described. The nickel/indium(I)‐mediated reaction of propargylic carbonates possessing different substitution patterns afforded syn‐homopropargylic alcohols in high yields upon coupling with a variety of carbonyl compounds. Both the nickel catalyst and the phosphane ligands were found to play a crucial role in this transformation. The diastereoselectivity is strongly dependent on the ligand employed. A mechanism involving umpolung of the propargylnickel intermediates under the influence of low‐valent indium is proposed to account for the dependence of the stereochemical characteristics of the phosphane ligands.
Enhancement of Electrochemiluminescence of Porous Silicon with Tri‐n‐propylamine as Co‐reactant
Authors: Mo Yan , Li Fucheng , Zheng Baozhan , Yang Suolong , Yuan Hongyan , Guo Yong , Xiao Dan
Published: September 2012

Visible light emission can be stimulated by applying a cyclic bias to a porous silicon/tri‐n‐propylamine (PS/TPrA) solid/liquid system. With the presence of 2.5 mM TPrA, the electrochemiluminescence intensity of the in situ formed PS electrode is 450 times higher than the blank solution. An applied voltage as low as 1.2 V is capable of generating light emission, indicating that current‐induced chemical reactions are an aid to the generation of charge carriers. A mechanism involving oxidation of TPrA followed by hole injection is proposed. The system also shows good ECL stability. In addition, the ECL emission can be inhibited by diphenols rather than phenol.
A Novel Process for the Fabrication of a Silver‐Nanoparticle‐Modified Electrode and Its Application in Nonenzymatic Glucose Sensing
Authors: Jia Mingzhe , Wang Tong , Liang Fenfen , Hu Jingbo
Published: September 2012

In this work, we present a novel process for fabrication of a silver‐nanoparticle‐modified electrode using silver ion implantation. This method is facile, low‐cost and environmental friendly without the use of any other chemicals. The obtained AgNPs on the electrode surface, which were free from any reagents surrounding or binding to them, showed prominent electrocatalytic activity towards the oxidation of glucose, leading to a nonenzymatic glucose sensor with a wide linear range and a detection limit of 0.5 µM. In addition, the modified electrode also exhibited acceptable reproducibility and long‐term stability.
Energy Dispersive X‐ray Diffraction Applied to Laboratory Investigation on Proton Exchange Membrane Water Content in Working Fuel Cells
Authors: Isopo A. , Nobili F. , Rossi Albertini V.
Published: September 2012

An original method, based on the energy‐dispersive X‐ray diffraction, has been recently proposed as a possible laboratory tool to accomplish long time resolved investigation of the water content in a proton exchange membrane fuel cell.

However, this method has never been applied to a real working fuel cell. Therefore, a clear comprehension of its effectiveness in terms of relevant parameters such as time and space resolution, sensitivity, and reproducibility has not yet been achieved. In this paper, all these aspects are discussed and clarified.

In order to focus on the method overall effectiveness and on the extent of possible improvements, a basic experimental configuration for both the electrochemical station and the X‐ray equipment has been set.

The method is described with particular attention to its operating principle and to the evaluation of the errors introduced in data assessment. Finally, applications to some model experiments, in particular working states of the device, are provided and the obtained results are discussed.
Barodesy as a novel hypoplastic constitutive theory based on the asymptotic behaviour of sand
Authors: Kolymbas Dimitrios
Published: September 2012

A new type constitutive equation of the rate type T̊ = h(T,D,e) for granular materials is introduced in the frame of Rational Mechanics. This new approach to constitutive modelling, called “barodesy”, is based on the asymptotic behaviour of sand. Barodesy can be seen as a further development of hypoplasticity. Despite its striking mathematical simplicity, it captures many aspects of sand behaviour.

Barodesie als eine neue hypoplastische Stofftheorie auf der Grundlage des asymptotischen Verhaltens von Sand. Es wird eine konstitutive Gleichung vom Ratentyp T̊ = h(T,D,e) für granulare Stoffe im Rahmen der sog. Rational Mechanics eingeführt. Diese neue Betrachtung von Stoffmodellen, genannt “Barodesie”, beruht auf das asymptotische Verhalten von Sand und kann als eine Weiterentwicklung der Hypoplastizität betrachtet werden. Trotz der auffälligen mathematischen Einfachheit, kann sie viele Aspekte des Verhaltens von Sand beschreiben.
Surgical margins in head and neck cancer: A contemporary review
Authors: Hinni Michael L. , Ferlito Alfio , Brandwein‐Gensler Margaret S. , Takes Robert P. , Silver Carl E. , Westra William H. , Seethala Raja R. , Rodrigo Juan P. , Corry June , Bradford Carol R. , Hunt Jennifer L. , Strojan Primož , Devaney Kenneth O. , Gnepp Douglas R. , Hartl Dana M. , Kowalski Luiz P. , Rinaldo Alessandra , Barnes Leon
Published: September 2012

Adequate resection margins are critical to the treatment decisions and prognosis of patients with head and neck squamous cell carcinoma (HNSCC). However, there are numerous controversies regarding reporting and interpretation of the status of resection margins. Fundamental issues relating to the basic definition of margin adequacy, uniform reporting standards for margins, optimal method of specimen dissection, and the role of intraoperative frozen section evaluation, all require further clarification and standardization. Future horizons for margin surveillance offer the possible use of novel methods such as “molecular margins” and contact microscopic endoscopy, However, the limitations of these approaches need to be understood. The goal of this review was to evaluate these issues to define a more rational, standardized approach for achieving resection margin adequacy for patients with HNSCC undergoing curative resection. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Serum Hepatitis B Surface Antigen Levels Help Predict Disease Progression in Patients With Low Hepatitis B Virus Loads
Authors: Tseng Tai-Chung , Liu Chun-Jen , Yang Hung-Chih , Su Tung-Hung , Wang Chia-Chi , Chen Chi-Ling , Hsu Cheng-An , Kuo Stephanie Fang-Tzu , Liu Chen-Hua , Chen Pei-Jer , Chen Ding-Shinn , Kao Jia-Horng
Published: September 2012

Chronic hepatitis B patients with high viral loads are at increased risk of cirrhosis and hepatocellular carcinoma (HCC). In patients with low viral loads, higher hepatitis B surface antigen (HBsAg) levels have been shown to predict HCC development. However, little is known about the difference in risk for other hepatitis B virus (HBV)-related adverse outcomes with varying HBsAg levels. A total of 1,068 Taiwanese hepatitis B e antigen (HBeAg)-negative HBV carriers with serum HBV DNA level <2,000 IU/mL at baseline were followed for a mean duration of 13.0 years. Patients were categorized based on their HBsAg levels, and the relationships between HBsAg level and development of HBeAg-negative hepatitis, hepatitis flare, and cirrhosis were investigated. Of the 1068 patients with low viral loads, 280 developed HBeAg-negative hepatitis, with an annual incidence rate of 2.0%. HBsAg level, but not HBV DNA level, was found to be a risk factor for HBeAg-negative hepatitis. Multivariate analysis showed that the adjusted hazard ratio in patients with an HBsAg level ≥1,000 versus <1000 IU/mL was 1.5 (95% confidence interval, 1.2–1.9). The positive correlation was present when evaluating other endpoints, including hepatitis flare and cirrhosis, and remained consistent when the study population was restricted to those with normal alanine aminotransferase (ALT) level at baseline. The annual incidence rate of HBeAg-negative hepatitis was lowered to 1.1% in patients with low levels of HBV DNA, HBsAg, and ALT.

Conclusion:

In HBeAg-negative patients with low viral loads and genotype B or C virus infection, a higher HBsAg level can predict disease progression. HBsAg <1,000 IU/mL in combination with low levels of HBV DNA and ALT help define minimal-risk HBV carriers.
A Role for Hepatic Leptin Signaling in Lipid Metabolism via Altered Very Low Density Lipoprotein Composition and Liver Lipase Activity in Mice
Authors: Huynh Frank K. , Neumann Ursula H. , Wang Ying , Rodrigues Brian , Kieffer Timothy J. , Covey Scott D.
Published: September 2012

Obesity is highly associated with dyslipidemia and cardiovascular disease. However, the mechanism behind this association is not completely understood. The hormone leptin may be a molecular link between obesity and dysregulation of lipid metabolism. Leptin can affect lipid metabolism independent of its well-known effects on food intake and energy expenditure, but exactly how this occurs is ill-defined. We hypothesized that since leptin receptors are found on the liver and the liver plays an integral role in regulating lipid metabolism, leptin may affect lipid metabolism by acting directly on the liver. To test this hypothesis, we generated mice with a hepatocyte-specific loss of leptin signaling. We previously showed that these mice have increased insulin sensitivity and elevated levels of liver triglycerides compared with controls. Here, we show that mice lacking hepatic leptin signaling have decreased levels of plasma apolipoprotein B yet increased levels of very low density lipoprotein (VLDL) triglycerides, suggesting alterations in triglyceride incorporation into VLDL or abnormal lipoprotein remodeling in the plasma. Indeed, lipoprotein profiles revealed larger apolipoprotein B-containing lipoprotein particles in mice with ablated liver leptin signaling. Loss of leptin signaling in the liver was also associated with a substantial increase in lipoprotein lipase activity in the liver, which may have contributed to increased lipid droplets in the liver.

Conclusion:

Lack of hepatic leptin signaling results in increased lipid accumulation in the liver and larger, more triglyceride-rich VLDL particles. Collectively, these data reveal an interesting role for hepatic leptin signaling in modulating triglyceride metabolism.
Wilson's Disease: Changes in Methionine Metabolism and Inflammation Affect Global DNA Methylation in Early Liver Disease
Authors: Medici Valentina , Shibata Noreene M. , Kharbanda Kusum K. , LaSalle Janine M. , Woods Rima , Liu Sarah , Engelberg Jesse A. , Devaraj Sridevi , Török Natalie J. , Jiang Joy X. , Havel Peter J. , Lönnerdal Bo , Kim Kyoungmi , Halsted Charles H.
Published: September 2012

Hepatic methionine metabolism may play an essential role in regulating methylation status and liver injury in Wilson's disease (WD) through the inhibition of S-adenosylhomocysteine hydrolase (SAHH) by copper (Cu) and the consequent accumulation of S-adenosylhomocysteine (SAH). We studied the transcript levels of selected genes related to liver injury, levels of SAHH, SAH, DNA methyltransferases genes (

Dnmt1, Dnmt3a, Dnmt3b

), and global DNA methylation in the tx-j mouse (tx-j), an animal model of WD. Findings were compared to those in control C3H mice, and in response to Cu chelation by penicillamine (PCA) and dietary supplementation of the methyl donor betaine to modulate inflammatory and methylation status. Transcript levels of selected genes related to endoplasmic reticulum stress, lipid synthesis, and fatty acid oxidation were down-regulated at baseline in tx-j mice, further down-regulated in response to PCA, and showed little to no response to betaine. Hepatic

Sahh

transcript and protein levels were reduced in tx-j mice with consequent increase of SAH levels. Hepatic Cu accumulation was associated with inflammation, as indicated by histopathology and elevated serum alanine aminotransferase (ALT) and liver tumor necrosis factor alpha (

Tnf

-α) levels.

Dnmt3b

was down-regulated in tx-j mice together with global DNA hypomethylation. PCA treatment of tx-j mice reduced

Tnf

-α and ALT levels, betaine treatment increased S-adenosylmethionine and up-regulated

Dnmt3b

levels, and both treatments restored global DNA methylation levels.

Conclusion:

Reduced hepatic

Sahh

expression was associated with increased liver SAH levels in the tx-j model of WD, with consequent global DNA hypomethylation. Increased global DNA methylation was achieved by reducing inflammation by Cu chelation or by providing methyl groups. We propose that increased SAH levels and inflammation affect widespread epigenetic regulation of gene expression in WD.
Neuronal and extraneuronal release of ATP and NAD+ in smooth muscle
Authors: Mutafova‐Yambolieva Violeta N.
Published: September 2012

Adenosine 5′‐triphosphate (ATP) and nicotinamide adenine dinucleotide (NAD+) are key intracellular constituents involved in energy transfer and redox homeostasis in the cell. ATP is also released in the extracellular space and in the past half century it has been assumed to be the purinergic neurotransmitter in many systems including smooth muscle. In some smooth muscles (i.e., the human urinary bladder detrusor muscle), ATP does appear to be primarily released from nerves upon action potential firings, but in other smooth muscles (i.e., the human large intestine), ATP does not mimic the endogenous purine neurotransmitter. It was recently found that NAD+, another ubiquitous intracellular adenine nucleotide, also follows a regulated release in neurosecretory cells, vascular and visceral smooth muscles, and the brain. In some cases, NAD+ fulfills presynaptic and postsynaptic criteria for a neurotransmitter better than ATP. Therefore, the purine hypothesis of neural regulation in smooth muscle is in need of reevaluation. This article will briefly review the current understanding of neuronal and extraneuronal release of purines in smooth muscle with emphasis on the roles of extracellular ATP and NAD+ and, further, will discuss more recent information about the likely involvement of multiple purines in smooth muscle neurotransmission. © 2012 IUBMB IUBMB Life, 2012, IUBMB Life, 64(10):817–824, 2012
A personal account
Authors: Daniel Senator
Published: September 2012

In 1959, Daniel K. Inouye became the first Congressman elected to the United States House of Representatives from the State of Hawaii. He arrived at that post after five years of service in the government of the Territory. In 1962 he was elected to the United States Senate, a position he still holds. He has been an active, productive Senator; having served on many committees. He is currently Chairman, Senate Select Committee on Intelligence. Senator Inouye chose a career in law and politics after the loss of his right arm in World War II prevented fulfillment of his lifelong goal to become a surgeon.
STATE DEPENDENCE AND HETEROGENEITY IN HEALTH USING A BIAS‐CORRECTED FIXED‐EFFECTS ESTIMATOR
Authors: Carro Jesus M. , Traferri Alejandra
Published: September 2012

This paper estimates a dynamic ordered probit model of self‐assessed health with two fixed effects: one in the linear index equation and one in the cut‐points. This robustly controls for heterogeneity in unobserved health status and in reporting behavior, although we cannot separate both sources of heterogeneity. We find important state dependence effects, and small but significant effects of income and other socioeconomic variables. Having dynamics and flexibly accounting for unobserved heterogeneity matters for those estimates. We also contribute to the bias correction literature in nonlinear panel models by comparing and applying two of the existing proposals to our model. Copyright © 2012 John Wiley & Sons, Ltd.
Failure Mode Analysis of Membrane Electrode Assembly (MEA) for PEMFC under Low Humidity Operation
Authors: Wang Cheng‐hong , Lai Chien‐ming , Huang Wei‐han , Lin Jiunn‐nan , Tsai Li‐duan
Published: September 2012

The degradation mechanisms and phenomena of membrane electrode assembly (MEA) for proton exchange membrane fuel cell (PEMFC under low humidity operation were investigated by means of several on‐line electrochemical methods and transmission electron microscopy (TEM). Electrochemical active surface area (ECSA) of catalyst and hydrogen crossover of MEA were evaluated by cyclic voltagram (CV) and linear sweep voltagram (LSV), respectively. The decrease of catalytic active site and degradation of membrane were evident by ECSA loss and hydrogen crossover rate increase after long‐term discharging test. Membrane degradation played the major role for MEAs failure under low humidity operation in this study. The Pt clusters were also observed in the membrane, formed by Pt ions migration and reduction in the membrane, which can react with the crossover gases to produce free radicals that attack membrane and ionomers in the catalyst layer.Those phenomena will drive membrane to rupture and cause a short circuit in MEA. By AST experiments and fluoride release rate results, the MEA with Pt‐alloy/C catalyst can show better performance and durability due to its high selectivity on ORR to depress the free radicals formation.
Organic Thin Film Transistors Based on 2,3‐Dimethylpentacene and 2,3‐Dimethyltetracene
Authors: Valiyev Famil , Huang Chi‐Wei , Sheu Hwo‐Shuenn , Tao Yu‐Tai
Published: September 2012

2,3‐Dimethylpentacene (DMP) and 2,3‐dimethyltetracene (DMT) were synthesized, characterized and employed as the channel material in the fabrication of thin‐film transistors. The two methyl groups increase the chemical stability of the compounds versus the pristine acene analogues. The crystals maintain herringbone‐like molecular packing, whereas the weak dipole associated with the unsymmetrical molecule induces an anti‐parallel alignment among the neighbors. This structural motif favors layered film growth on SiO2/Si surface. Thin film transistors prepared on SiO2/Si and n‐nonyltrichlorosilane‐modified SiO2/Si at different substrate temperatures were compared. DMP‐based transistors prepared on rubbed n‐nonyltrichlorosilane‐modified SiO2/Si substrate gave the highest field‐effect mobility of 0.46 cm2/Vs, whereas DMT‐based transistor gave a mobility of 0.028 cm2/Vs.
THE IMPACT OF THE 2008–2009 CRISIS ON COMMODITY‐DEPENDENT LOW‐INCOME AFRICAN COUNTRIES: CONFIRMING THE RELEVANCE OF THE CONCEPT OF POVERTY TRAP?
Authors: Sindzingre Alice
Published: September 2012

Focusing on low‐income commodity‐dependent sub‐Saharan African countries, the paper argues that the impact of the 2008–2009 crisis, and more generally, these countries' growth trajectories, can be explained by the concept of the poverty trap. This is not trivial, because commodity‐based traps remain debated: some countries have grounded their growth on the export of commodities, and the impact of commodity price fluctuations may be analysed through other concepts (such as cycles). Against these views, it shows that these countries' growth trajectories exhibit the three key theoretical features of poverty traps: threshold effects, cumulative causation and low equilibria. Copyright © 2012 John Wiley & Sons, Ltd.
Differential growth and yield by canola (Brassica napus L.) and wheat (Triticum aestivum L.) arising from alterations in chemical properties of sandy soils due to additions of fly ash
Authors: Yunusa Isa A M , Manoharan Veeragathipillai , Harris Rob , Lawrie Roy , Pal Yash , Quiton Jonathan T , Bell Richard , Eamus Derek
Published: September 2012

Background

There is a need for field trials on testing agronomic potential of coal fly ash to engender routine use of this technology. Two field trials were undertaken with alkaline and acidic fly ashes supplied at between 3 and 6 Mg ha−1 to acidic soils and sown to wheat and canola at Richmond (Eastern Australia) and to wheat only at Merredin (Western Australia).

Results

Ash addition marginally (P< 0.10) raised the pH in the top soil layers at both sites. The exceptionally dry season at both sites constrained yields and thwarted any likelihood of gaining yield benefits from ash‐induced improvements in soil conditions. Yield improvements due to ash addition were absent at Merredin and only marginal at Richmond, where no elevated accumulation of B, Mo, Se, P or S in either the straw or seeds of wheat was observed; canola increased accumulation of Mo and Se in its shoot with acidic fly ash, but it was well below phyto toxic levels. Simulations of wheat using APSIM at Richmond over a 100‐year period (1909–2008) predicted yield increases in 52% of years with addition of ash at 3.0 Mg ha−1 compared with 24% of years with addition of ash at 6.0 Mg ha−1. The simulated yield increases did not exceed 40% over the control with addition of 6 Mg ha−1 ash, but was between 40% and 50% with an addition rate of 3 Mg ha−1.

Conclusion

We found no evidence of phytotoxicity in either crop in this unusually dry year and there is still a need for further field assessment in years with favourable rainfall to enable development of clear recommendations on fly ash rates for optimum yield benefits.© 2012 Society of Chemical Industry
18F‐fluorodeoxyglucose uptake predicts pathological complete response after neoadjuvant chemotherapy for breast cancer: A retrospective cohort study
Authors: Jin Soyoung , Kim Sung‐Bae , Ahn Jin‐Hee , Jung Kyung Hae , Ahn Sei Hyun , Son Byung Ho , Lee Jong Won , Gong Gyungyub , Kim Hye Ok , Moon Dae Hyuk
Published: September 2012

Background and Objectives

18F‐fluorodeoxyglucose (18F‐FDG) uptake may identify poorly differentiated tumors with a high proliferation rate that are more responsive to neoadjuvant chemotherapy.

Methods

We retrospectively evaluated 273 patients (mean age, 44.2 years; range 23–78 years) newly diagnosed with stage II or III invasive ductal breast cancer between 2006 and 2010. All patients were treated with neoadjuvant chemotherapy followed by surgery. The ability of parameters to predict pathological complete response (pCR), was assessed by multivariate analysis.

Results

Of the 273 breast cancer patients, 30 (11.0%) achieved pCR. Univariate analysis revealed that higher histologic grade (P < 0.001), lack of estrogen receptor (ER, P < 0.001); and a higher maximal standardized uptake value (SUVmax, P < 0.001) were associated with pCR, whereas HER2/neu amplification and Ki‐67 expression were not (P > 0.05 for each comparison). Multivariate analysis showed that negative ER (odds ratio [OR] = 9.98; 95% confidence interval [CI], 2.88–34.52, P < 0.001) and the SUVmax of 18F‐FDG uptake (OR per one unit increase in SUVmax = 1.09; 95% CI, 1.02–1.16, P = 0.008) were independent predictors of pCR.

Conclusions

ER status and 18F‐FDG uptake are independent predictors of pCR after neoadjuvant chemotherapy for breast cancer. J. Surg. Oncol. 2013;107:180–187. © 2012 Wiley Periodicals, Inc.
Development and validation of an HPLC method to determine metabolites of 5‐hydroxymethylfurfural (5‐HMF)
Authors: Hardt‐Stremayr Magdalena , Bernaskova Marketa , Hauser Stefanie , Kunert Olaf , Guo Xinghua , Stephan Janette , Spreitz Josef , Lankmayr Ernst , Schmid Martin G. , Wintersteiger Reinhold
Published: September 2012

The food component 5‐hydroxymethylfurfural is supposed to have antioxidative properties and is therefore used as an acting agent in a novel anticancer infusion solution, named Karal®, and an oral supplementation. Previous studies showed that after oral and intravenous application, the substance is completely decomposed to its metabolites: 5‐hydroxymethylfuroic acid, 2,5‐furandicarboxylic acid, and N‐(hydroxymethyl)furoyl glycine. The formation of a fourth metabolite, namely 5‐sulphoxymethylfurfural, is still not clarified according to literature. Due to commercial unavailability, synthesis of 5‐sulphoxymethylfurfural was conducted and a synthesis procedure for N‐(hydroxymethyl)furoyl glycine had to be developed. Identification of the synthesised compounds was proven by LC‐MS and NMR. An appropriate HPLC method was established to obtain good separation of the four possible metabolic substances and 5‐hydroxymethylfurfural within 12 min via a HILIC column (150 × 4.6 mm, 5 μm) using a gradient grade system switching from mobile phase A (ACN/ammonium formate 100 mM, pH 2.35, 95:5, v/v) to mobile phase B (ACN/ammonium formate 100 mM, pH 2.35, 85:15, v/v). The procedure was afterward validated following ICH guidelines in terms of selectivity, linearity, precision, LOD, and LOQ.
Validation of the extended Tanaka column characterization protocol by multivariate analysis of chromatographic retention of low‐molecular‐weight analytes on reversed phase columns using methanol and acetonitrile as organic modifiers
Authors: Euerby Melvin R , James Matthew , Axelsson Bengt‐Olof , Rosén Olof , Petersson Patrik
Published: September 2012

The validity of the extended Tanaka column characterization procedure against the retention behavior of 101 analytes of widely differing properties chromatographed on five differing stationary phase chemistries has been established using a chemometric technique called principal component analysis (PCA). It was concluded that the simple and conveniently determined column characterization parameters covered the same space in the PCA loading plot as the retention times for the 101 differing analytes. This confirms that the ten column characterization parameters of the extended Tanaka protocol encode the same information as the retention times of the 101 analytes. Significant selectivity differences were observed between stationary phases and the mobile‐phase modifiers – MeOH and MeCN. PCA contribution plots served as a convenient way to highlight specific selectivity differences between stationary phases. logD values exhibited a poor correlation with retention indicating that retention in RP‐LC is not solely dictated by the analyte's hydrophobicity. The use of MeOH was found to generate greater selectivity differences with the five stationary phases than when MeCN is used.
Decyl‐perfluorinated magnetic mesoporous microspheres for extraction and analysis perfluorinated compounds in water using ultrahigh‐performance liquid chromatography–mass spectrometry
Authors: Yang Lei , Yu Wenjia , Yan Xiaomin , Deng Chunhui
Published: September 2012

In this work, the interior‐walls decyl‐perfluorinated functionalized magnetic mesoporous microspheres (F17–Fe3O4@mSiO2) were synthesized for the first time, and applied as adsorbents to extract and concentrate perfluorinated compounds (PFCs) from water samples. The fluorous functionalized interior pore‐walls contributed to the high‐selective preconcentration of PFCs due to fluorous affinity; and abundant silanol groups on the exterior surface of microspheres contributed to the good dispersibility in water sample. Four kinds of PFCs were selected as model analytes, including perfluorooctanoic acid, perfluorononanoic acid, perfluorododecanoic acid, and perfluorooctane sulphonate. In addition, UHPLC‐ESI/MS/MS was introduced to the fast and sensitive detection of the analytes after sample pretreatment. Important parameters of the extraction procedure were optimized, including salinity, eluting solvent, the amount of F17–Fe3O4@mSiO2 microspheres, and extraction time. The optimized procedure took only 10 min to extract analytes with high recoveries and merely 800‐μL acetonitrile to elute analytes from the magnetic adsorbents. Validation experiments showed good linearity (0.994–0.998), precision (2.6–7.6%), high recovery (93.4–105.7%) of the proposed method, and the limits of detection were from 0.008 to 0.125 μg/L. The F17–Fe3O4@mSiO2 magnetic microspheres have the advantages of great dispersibility in aqueous solution, high specificity of extraction, large surface area, and efficient separation ability. The results showed that the proposed method based on F17–Fe3O4@mSiO2 microspheres is a simple, fast, and sensitive tool for the analysis of PFCs in water sample.
Ultrasound‐assisted matrix solid phase dispersive extraction for the simultaneous analysis of β‐lactams (four penicillins and eight cephalosporins) in milk by high performance liquid chromatography with photodiode array detection
Authors: Karageorgou Eftichia G. , Samanidou Victoria F. , Papadoyannis Ioannis N.
Published: September 2012

The application of ultrasound‐assisted matrix solid phase dispersive extraction for the confirmatory analysis of 12 β‐lactam antibiotics in milk by high performance liquid chromatography with photodiode array detection has been proposed herein. Four penicillins (cloxacillin, dicloxacillin, oxacillin, and amoxicillin) and eight cephalosporins (cefaclor, cefadroxil, ceftiofur, cefuroxime, cefoperazone, cefazolin, cephalexin, and cefotaxime) are effectively extracted using a mixed sorbent of Quick Easy Cheap Effective Rugged Safe technique and OASIS HLB providing a matrix free from any endogenous interference. Examined analytes were well resolved on an Inertsil ODS‐3 analytical column with a mobile phase of CH3COONH4 (0.05 M) and acetonitrile delivered under a gradient program. 1,7‐Dimethyl‐xanthine was used as internal standard. The method was validated meeting the European Legislation determining linearity, selectivity, stability, decision limit, detection capability, accuracy, precision, and ruggedness according to the Youden approach. Recoveries of all antibiotics rated from 85.0 to 115.7%, while RSD values were <12.7%. Finally, the method was successfully applied to milk samples purchased from local market.
Compact Optical systems for Micromanipulation
Authors: Sinzinger Stefan , Oeder Andreas , Stoebenau Sebastian , Kampmann Ronald
Published: September 2012

Highly focused laser beams offer exciting possibilities for the handling and manipulation of small particles. Even though the technique of “optical tweezing” has been discussed and applied in research labs for more than 40 years a breakthrough in industrial applications has not taken place so far. Major obstacles result from the complex systems used to generate the necessary focus distribution. Our latest research indicates that optical tweezers based on compact and integrated optical systems are feasible. Such systems could open the field to a wide variety of new applications.
Metal Cutting with Multi kW Diode Laser
Authors: Lentjes Marco , Bruns Peter
Published: September 2012

Cutting roughness lower than 10 μm and a wall‐plug efficiency of 30% including cooling are two nameable advantages when speaking about direct diode laser cutting of metals. Emphasizing in this context “direct diode laser” stress that metal cutting with a diode laser is not a conventional process. However, steady developments in diode bar technology enabled the design of a high brightness diode laser system with 2 kW output power and a beam parameter product of 22 mm*mrad. This now commercially available “DIOCUT” system is ready to enter the laser macro cutting market. The applicability of this system is demonstrated by cutting aluminum, stainless steel, copper and mild steel. The cutting edge quality is comparable with CO2 laser cuts. On our roadmap is higher output power at equal beam quality in near future.
Saving gasoline is What counts!
Authors: Wenzlau Carsten
Published: September 2012

The automobile industry is assuming a leading role in environmentally friendly technology as R & D departments are continuously working on improving processes to boost efficiency and effectiveness. Fuel efficiency is what counts! customers have come to rely on fuel efficiency and attach great importance to economically and ecologically friendly products. As a result, the decision when purchasing an automobile is often associated with gasoline consumption and emission volume.
A Novel Type of Crown Ether‐Containing Metal Ions Optical Sensors Based on Polymer‐Stabilized Cholesteric Liquid Crystalline Films
Authors: Stroganov Vladislav , Ryabchun Alexander , Bobrovsky Alexey , Shibaev Valery
Published: September 2012

For the first time, the films based on polymer‐stabilized cholesteric composites containing crown ether fragments with the optical properties sensitive to the complexation with potassium and barium ions were obtained. The complexation with these ions leads to blue spectral shift of the selective light reflection of planar cholesteric texture of composite films. Peculiarities of spectral changes and kinetics of selective light reflection shift were studied. The proposed approach can be used for the creation of the effective and selective sensor materials for different ions or groups of ions.
Myogenic, matrix, and growth factor mRNA expression in human skeletal muscle: Effect of contraction intensity and feeding
Authors: Agergaard Jakob , Reitelseder Søren , Pedersen Troels G. , Doessing Simon , Schjerling Peter , Langberg Henning , Miller Benjamin F. , Aagaard Per , Kjær Michael , Holm Lars
Published: September 2012

Introduction: We examined short‐term (3‐hour) and long‐term (12‐week) training effects after heavy load [HL; 70% 1RM] and light load (LL; 16% 1RM) exercise. Methods: mRNA expression of genes involved in skeletal muscle remodeling were analyzed and muscle activity (EMG measurements) was measured. Results: Relative muscle activity differed between HL and LL resistance exercise, whereas median power frequency was even, suggesting an equal muscle‐fiber‐type recruitment distribution. mRNA expression of Myf6, myogenin, and p21 was mostly increased, and myostatin was mostly depressed by HL resistance exercise. No major differences were seen in atrophy‐related genes between HL and LL resistance exercise. No changes were seen over 12‐week training for any of the targets. Conclusions: Resistance exercise at LL and HL elevated the expression of genes involved in skeletal muscle hypertrophy, although the greatest response was from HL. However, no long‐term effect from either LL or HL resistance exercise was seen on basal levels of the mRNA targets. Muscle Nerve 47: 748–759, 2013
A review of calibrated blood oxygenation level‐dependent (BOLD) methods for the measurement of task‐induced changes in brain oxygen metabolism
Authors: Blockley Nicholas P. , Griffeth Valerie E. M. , Simon Aaron B. , Buxton Richard B.
Published: September 2012

The dynamics of the blood oxygenation level‐dependent (BOLD) response are dependent on changes in cerebral blood flow, cerebral blood volume and the cerebral metabolic rate of oxygen consumption. Furthermore, the amplitude of the response is dependent on the baseline physiological state, defined by the haematocrit, oxygen extraction fraction and cerebral blood volume. As a result of this complex dependence, the accurate interpretation of BOLD data and robust intersubject comparisons when the baseline physiology is varied are difficult. The calibrated BOLD technique was developed to address these issues. However, the methodology is complex and its full promise has not yet been realised. In this review, the theoretical underpinnings of calibrated BOLD, and issues regarding this theory that are still to be resolved, are discussed. Important aspects of practical implementation are reviewed and reported applications of this methodology are presented. Copyright © 2012 John Wiley & Sons, Ltd.
Treatment with the MEK inhibitor U0126 induces decreased hyperpolarized pyruvate to lactate conversion in breast, but not prostate, cancer cells
Authors: Lodi Alessia , Woods Sarah M. , Ronen Sabrina M.
Published: September 2012

Alterations in cell metabolism are increasingly being recognized as a hallmark of cancer and are being exploited for the development of diagnostic tools and targeted therapeutics. Recently, 13C MRS‐detectable hyperpolarized pyruvate to lactate conversion has been validated in models as a noninvasive imaging method for the detection of tumors and treatment response, and has successfully passed phase I clinical trials. To date, response to treatment has been associated with a decrease in hyperpolarized lactate production. In this study, we monitored the effect of treatment with the mitogen‐activated protein kinase (MEK) inhibitor U0126 in prostate and breast cancer cells. Following treatment, we observed a 31% decrease in the flux of hyperpolarized 13C label in treated MCF‐7 breast cancer cells relative to controls. In contrast, and unexpectedly, the flux increased to 167% in treated PC3 prostate cancer cells. To mechanistically explain these observations, we investigated treatment‐induced changes in the different factors known to affect the pyruvate to lactate conversion. NADH (nicotinamide adenine dinucleotide, reduced form) levels remained unchanged, whereas lactate dehydrogenase expression and activity, as well as intracellular lactate, increased in both cell lines, providing an explanation for the elevated hyperpolarized lactate observed in PC3 cells. The expression of MCT1, which mediates pyruvate transport, decreased in treated MCF‐7, but not PC3, cells. This identifies pyruvate transport as rate limiting in U0126‐treated MCF‐7 cells and explains the decrease in hyperpolarized lactate observed in these cells following treatment. Our findings highlight the complexity of interactions between MEK and metabolism, and the need for mechanistic validation before hyperpolarized 13C MRS can be used to monitor treatment‐induced molecular responses. Copyright © 2012 John Wiley & Sons, Ltd.
Do campaign strategies and tactics matter? Exploring party elite perceptions of what matters when explaining election outcomes
Authors: Strömbäck Jesper , Grandien Christina , Falasca Kajsa
Published: September 2012

In research on political campaign communication, it is often assumed that campaign strategies and tactics are highly important for explaining election outcomes. In contrast, most research in political science tends to emphasize the importance of political substance, long‐term factors such as party identification, and real‐world conditions for explaining election outcomes.

Although political parties in practice treat election campaigns as highly important and consequential, there is virtually no research on how party elites perceive the importance of campaign strategies and tactics when explaining election outcomes. Hence, drawing on a survey among Swedish members of parliament, this study investigates party elite perceptions of what matters when people decide which party to vote for and of what matters when explaining election outcomes. In brief, the results show that members of parliament perceive campaign strategies and tactics as significantly less important than the substance of politics. In the concluding analysis, the implications of the results are analyzed. Copyright © 2012 John Wiley & Sons, Ltd.