bluuebunny/crossref_metadata_2025 huggingface dataset:
Technical note: Introduction to MIMICA, a large‐eddy simulation solver for cloudy planetary boundary layers
Authors: Savre J. , Ekman A. M. L. , Svensson G.
Published: April 2014

In large‐eddy simulation (LES), large‐scale turbulent structures are explicitly resolved on the numerical grid while the dissipative turbulent eddies, typically smaller than the grid size, must be modeled. Because in the atmospheric boundary layer a large disparity of turbulent scales exists (about 9 orders of magnitude separate the largest and smallest scales), LES is considered as an essential modeling approach to capture the physics and dynamics of boundary layer clouds. A new LES solver developed at Stockholm University is presented here for the first time. The model solves for nonhydrostatic anelastic equations using high‐order low‐dissipative numerical schemes for the advection of scalars and momentum. A two‐moment bulk microphysics scheme is implemented representing five types of hydrometeors including ice crystals and snow. The LES is evaluated based on simulations of two well‐documented stratiform cloud events that were previously used for LES intercomparisons. In the first one, a marine drizzling stratocumulus observed during DYCOMS‐II, the model is shown to predict bulk cloud microphysical and dynamical properties within the range of the intercomparison model results. In the second case, based on a monolayer Arctic mixed‐phase cloud observed during ISDAC, we found that when using fast‐falling crystals, ice quickly precipitates out of the cloud without significant growth, resulting in very low ice water paths. The simulated clouds are also found to be very sensitive to the prescribed ice crystal number concentration: multiplying the ice concentration by a factor 2.5 results in rapid cloud dissipation in the most extreme case. Overall, these results are found to be consistent with former studies of Arctic mixed‐phase clouds as well as in situ measurements. More specifically, when the ice number concentration and parameterized ice habit are constrained by measurements, simulated microphysical properties such as the ice water path and ice crystal size distribution are found to agree well with observations.
Milk Consumption and Progression of Medial Tibiofemoral Knee Osteoarthritis: Data From the Osteoarthritis Initiative
Authors: Lu Bing , Driban Jeffrey B. , Duryea Jeffrey , McAlindon Timothy , Lapane Kate L. , Eaton Charles B.
Published: April 2014

Objective

Milk consumption has long been recognized for its important role in bone health, but its role in the progression of knee osteoarthritis (OA) is unclear. We examined the prospective association of milk consumption with radiographic progression of knee OA.

Methods

In the Osteoarthritis Initiative, 2,148 participants (3,064 knees) with radiographic knee OA and dietary data at baseline were followed up to 12, 24, 36, and 48 months. Milk consumption was assessed with a Block Brief Food Frequency Questionnaire completed at baseline. To evaluate progression of OA, we used quantitative joint space width (JSW) between the medial femur and tibia of the knee based on plain radiographs. The multivariate linear models for repeated measures were used to test the independent association between milk intake and the decrease in JSW over time, while adjusting for baseline disease severity, body mass index, dietary factors, and other potential confounders.

Results

We observed a significant dose‐response relationship between baseline milk intake and adjusted mean decrease of JSW in women (P = 0.014 for trend). With increasing levels of milk intake (none, ≤3, 4–6, and ≥7 glasses/week), the mean decreases of JSW were 0.38 mm, 0.29 mm, 0.29 mm, and 0.26 mm, respectively. In men, we observed no significant association between milk consumption and the decreases of JSW.

Conclusion

Our results suggest that frequent milk consumption may be associated with reduced OA progression in women. Replication of these novel findings in other prospective studies demonstrating the increase in milk consumption leads to delay in knee OA progression are needed.
Planar Microdevices for Enhanced In Vivo Retention and Oral Bioavailability of Poorly Permeable Drugs
Authors: Chirra Hariharasudhan D. , Shao Ling , Ciaccio Natalie , Fox Cade B. , Wade Jennifer M. , Ma Averil , Desai Tejal A.
Published: April 2014

The development of novel oral drug delivery platforms for administering therapeutics in a safe and effective manner through the harsh gastrointestinal environment is of great importance. Here, the use of engineered thin planar poly(methyl methacrylate) (PMMA) microdevices is tested to enhance oral bioavailability of acyclovir, a poorly permeable drug. Acyclovir is loaded into the unidirectional drug releasing microdevice reservoirs using a drug entrapping photocross‐linkable hydrogel matrix. An increase in acyclovir permeation across in vitro caco‐2 monolayer is seen in the presence of microdevices as compared with acyclovir‐entrapped hydrogels or free acyclovir solution. Cell proliferation studies show that microdevices are relatively nontoxic in nature for use in in vivo studies. Enhanced in vivo retention of microdevices is observed as their thin side walls experience minimal peristaltic shear stress as compared with spherical microparticles. Unidirectional acyclovir release and enhanced retention of microdevices achieve a 4.5‐fold increase in bioavailability in vivo as compared with an oral gavage of acyclovir solution with the same drug mass. The enhanced oral bioavailability results suggest that thin, planar, bioadhesive, and unidirectional drug releasing microdevices will significantly improve the systemic and localized delivery of a broad range of oral therapeutics in the near future.
Conjugated‐Polymer‐Based Energy‐Transfer Systems for Antimicrobial and Anticancer Applications
Authors: Yuan Huanxiang , Wang Bing , Lv Fengting , Liu Libing , Wang Shu
Published: April 2014

Conjugated polymers (CPs) attract a lot of attention in sensing, imaging, and biomedical applications because of recent achievements that are highlighted in this Research News article. A brief review of recent progress in the application of CP‐based energy‐transfer systems in antimicrobial and anticancer treatments is provided. The transfer of excitation energy from CPs to photosensitizers leads to the generation of reactive oxygen species (ROS) that are able to efficiently kill pathogenic microorganisms and cancer cells in the surroundings. Both fluorescence resonance energy transfer (FRET) and bioluminescence energy transfer (BRET) modes are discussed.
Equilibration of the [2+2] Cycloaddition of Silyl Enol Ethers Catalyzed by Ethylaluminium Dichloride: Diastereoselectivity Switch in the Synthesis of Fused Cyclobutanes
Authors: Hata Kenji , Arichi Norihito , Yamaoka Yousuke , Yamada Ken‐ichi , Takemoto Yoshiji , Takasu Kiyosei
Published: April 2014

The process by which the reaction between silyl enol ethers and acrylates reached equilibrium through an EtAlCl2‐catalyzed [2+2] cycloaddition was characterized. The mechanism and substrate scope of the retro [2+2] cycloaddition were investigated. The trans or cis isomers can be selectively obtained by controlling the reaction temperature, although the substrate scope was found to be limited.
On the tool use behavior of the bonobo‐chimpanzee last common ancestor, and the origins of hominine stone tool use
Authors: Haslam Michael
Published: April 2014

The last common ancestor (LCA) shared by chimpanzees (Pan troglodytes) and bonobos (P. paniscus) was an Early Pleistocene African ape, which, based on the behavior of modern chimpanzees, may be assumed to be a tool‐using animal. However, the character of tool use in thePanlineage prior to the 20th century is largely unknown. Here, I use available data on wild bonobo tool use and emerging molecular estimates of demography duringPanevolution to hypothesise the plausible tool use behavior of the bonobo‐chimpanzee LCA (or “Pancestor”) at the start of the Pleistocene, over 2 million years ago. This method indicates that the common ancestor of livingPanapes likely used plant tools for probing, sponging, and display, but it did not use stone tools. Instead, stone tool use appears to have been independently invented by Western African chimpanzees (P. t. verus) during the Middle Pleistocene in the region of modern Liberia‐Ivory Coast‐Guinea, possibly as recently as 200,000–150,000 years ago. If this is the case, then the LCA of humans and chimpanzees likely also did not use stone tools, and this trait probably first emerged among hominins in Pliocene East Africa. This review also suggests that the consistently higher population sizes of Central African chimpanzees (P. t. troglodytes) over the past million years may have contributed to the increased complexity of wild tool use seen in this sub‐species today. Am. J. Primatol. 76:910–918, 2014. © 2014 Wiley Periodicals, Inc.
Behavioral flexibility of vervet monkeys in response to climatic and social variability
Authors: McFarland Richard , Barrett Louise , Boner Ria , Freeman Natalie J. , Henzi S. Peter
Published: April 2014

Responses to environmental variability sheds light on how individuals are able to survive in a particular habitat and provides an indication of the scope and limits of its niche. To understand whether climate has a direct impact on activity, and determine whether vervet monkeys have the behavioral flexibility to respond to environmental change, we examined whether the amount of time spent resting and feeding in the nonmating and mating seasons were predicted by the thermal and energetic constraints of ambient temperature. Our results show that high temperatures during the nonmating season were associated with an increase in time spent resting, at the expense of feeding. Cold temperatures during the nonmating season were associated with an increase in time spent feeding, at the expense of resting. In contrast, both feeding and resting time during the mating season were independent of temperature, suggesting that animals were not adjusting their activity in relation to temperature during this period. Our data indicate that climate has a direct effect on animal activity, and that animals may be thermally and energetically compromised in the mating season. Our study animals appear to have the behavioral flexibility to tolerate current environmental variability. However, future climate change scenarios predict that the time an animal has available for behaviors critical for survival will be constrained by temperature. Further investigations, aimed at determining the degree of behavioral and physiological flexibility displayed by primates, are needed if we are to fully understand the consequences of environmental change on their distribution and survival. Am J Phys Anthropol 154:357–364, 2014. © 2014 Wiley Periodicals, Inc.
Surmounting retraining limits in Musicians' dystonia by transcranial stimulation
Authors: Furuya Shinichi , Nitsche Michael A. , Paulus Walter , Altenmüller Eckart
Published: April 2014

Objective

Abnormal cortical excitability is evident in various movement disorders that compromise fine motor control. Here we tested whether skilled finger movements can be restored in musicians with focal hand dystonia through behavioral training assisted by transcranial direct current stimulation to the motor cortex of both hemispheres.

Methods

The bilateral motor cortices of 20 pianists (10 with focal dystonia, 10 healthy controls) were electrically stimulated noninvasively during bimanual mirrored finger movements.

Results

We found improvement in the rhythmic accuracy of sequential finger movements with the affected hand during and after cathodal stimulation over the affected cortex and simultaneous anodal stimulation over the unaffected cortex. The improvement was retained 4 days after intervention. Neither a stimulation with the reversed montage of electrodes nor sham stimulation yielded any improvement. Furthermore, the amount of improvement was positively correlated with the severity of the symptoms. Bihemispheric stimulation without concurrent motor training failed to improve fine motor control, underlining the importance of combined retraining and stimulation for restoring the dystonic symptoms. For the healthy pianists, none of the stimulation protocols enhanced movement accuracy.

Interpretation

These results suggest a therapeutic potential of behavioral training assisted by bihemispheric, noninvasive brain stimulation in restoring fine motor control in focal dystonia. ANN NEUROL 2014;75:700–707
Simultaneous Spray Self‐Assembly of Highly Loaded ZIF‐8–PDMS Nanohybrid Membranes Exhibiting Exceptionally High Biobutanol‐Permselective Pervaporation
Authors: Fan Hongwei , Shi Qi , Yan Hao , Ji Shulan , Dong Jinxiang , Zhang Guojun
Published: April 2014

The ability to obtain a maximum loading of inorganic nanoparticles while maintaining uniform dispersion in the polymer is the key to the fabrication of mixed‐matrix membranes with high pervaporation performance in bioalcohol recovery from aqueous solution. Herein, we report the simultaneous spray self‐assembly of a zeolitic imidazolate framework (ZIF)–polymer suspension and a cross‐linker/catalyst solution as a method for the fabrication of a well‐dispersed ZIF‐8–PDMS nanohybrid membrane with an extremely high loading. The ZIF‐8–PDMS membrane showed excellent biobutanol‐permselective pervaporation performance. When the ZIF‐8 loading was increased to 40 wt %, the total flux and separation factor could reach 4846.2 g m−2 h−1 and 81.6, respectively, in the recovery of n‐butanol from 1.0 wt % aqueous solution (80 °C). This new method is expected to have serious implications for the preparation of defect‐free mixed‐matrix membranes for many applications.
Bor‐Radikalkationen durch Oxidation elektronenreicher Diborene
Authors: Bissinger Philipp , Braunschweig Holger , Damme Alexander , Kupfer Thomas , Krummenacher Ivo , Vargas Alfredo
Published: April 2014

Die Herstellung eines Phosphan‐stabilisierten Diborens, Et3P⋅(Mes)BB(Mes)⋅PEt3 (4), durch Reduktion von Et3P⋅B2Me s2Br2 mit KC8 in Benzol ermöglichte erstmals eine detaillierte Untersuchung der elektronischen Eigenschaften der BB‐Bindung im Vergleich mit dem kürzlich beschriebenen NHC‐stabilisierten Diboren IMe⋅(Dur)BB(Dur)⋅IMe (1). Ein entscheidendes Merkmal dieser Spezies ist die Gegenwart ungewöhnlich elektronenreicher Borzentren. Cyclovoltammetrie, UV/Vis‐Spektroskopie und DFT‐Rechnungen offenbarten eine starke Abhängigkeit der Reduktionspotentiale und Absorptionseigenschaften der BB‐Bindung von der Lewis‐Base. Demnach bedingt die stärkere σ‐Donorfähigkeit und höhere Elektronegativität des NHC‐Liganden ein energetisch höherliegendes HOMO, was 1 zu einem stärkeren neutralen Reduktionsmittel macht als 4 (1: E1/2=−1.55 V; 4: −1.05 V), sowie einen kleineren HOMO‐LUMO‐Abstand in 1, verbunden mit einer signifikanten Rotverschiebung der niederenergetischsten Absorptionsbande im Vergleich zu 4. Wegen ihrer stark negativen Reduktionspotentiale können die Diborene 1 und 4 relativ einfach zu sehr seltenen Bor‐zentrierten Radikalkationen oxidiert werden (5 und 6).
Entropy is Key to the Formation of Pentacyclic Terpenoids by Enzyme‐Catalyzed Polycyclization
Authors: Syrén Per‐Olof , Hammer Stephan C. , Claasen Birgit , Hauer Bernhard
Published: April 2014

Polycyclizations constitute a cornerstone of chemistry and biology. Multicyclic scaffolds are generated by terpene cyclase enzymes in nature through a carbocationic polycyclization cascade of a prefolded polyisoprene backbone, for which electrostatic stabilization of transient carbocationic species is believed to drive catalysis. Computational studies and site‐directed mutagenesis were used to assess the contribution of entropy to the polycyclization cascade catalyzed by the triterpene cyclase from A. acidocaldarius. Our results show that entropy contributes significantly to the rate enhancement through the release of water molecules through specific channels. A single rational point mutation that results in the disruption of one of these water channels decreased the entropic contribution to catalysis by 60 kcal mol−1. This work demonstrates that entropy is the key to enzyme‐catalyzed polycyclizations, which are highly relevant in biology since 90 % of all natural products contain a cyclic subunit.
In Situ Synthesis of Robust Conductive Cellulose/Polypyrrole Composite Aerogels and Their Potential Application in Nerve Regeneration
Authors: Shi Zhuqun , Gao Huichang , Feng Jiao , Ding Beibei , Cao Xiaodong , Kuga Shigenori , Wang Yingjun , Zhang Lina , Cai Jie
Published: April 2014

Nanostructured conductive polymers can offer analogous environments for extracellular matrix and induce cellular responses by electric stimulation, however, such materials often lack mechanical strength and tend to collapse under small stresses. We prepared electrically conductive nanoporous materials by coating nanoporous cellulose gels (NCG) with polypyrrole (PPy) nanoparticles, which were synthesized in situ from pyrrole monomers supplied as vapor. The resulting NCG/PPy composite hydrogels were converted to aerogels by drying with supercritical CO2, giving a density of 0.41–0.53 g cm−3, nitrogen adsorption surface areas of 264–303 m2 g−1, and high mechanical strength. The NCG/PPy composite hydrogels exhibited an electrical conductivity of up to 0.08 S cm−1. In vitro studies showed that the incorporation of PPy into an NCG enhances the adhesion and proliferation of PC12 cells. Electrical stimulation demonstrated that PC12 cells attached and extended longer neurites when cultured on NCG/PPy composite gels with DBSA dopant. These materials are promising candidates for applications in nerve regeneration, carbon capture, catalyst supports, and many others.
Surface‐Enhanced Raman Spectroscopy: Concepts and Chemical Applications
Authors: Schlücker Sebastian
Published: April 2014

Surface‐enhanced Raman scattering (SERS) has become a mature vibrational spectroscopic technique during the last decades and the number of applications in the chemical, material, and in particular life sciences is rapidly increasing. This Review explains the basic theory of SERS in a brief tutorial and—based on original results from recent research—summarizes fundamental aspects necessary for understanding SERS and provides examples for the preparation of plasmonic nanostructures for SERS. Chemical applications of SERS are the centerpiece of this Review. They cover a broad range of topics such as catalysis and spectroelectrochemistry, single‐molecule detection, and (bio)analytical chemistry.
A highly efficient β‐nucleating agent for impact‐resistant polypropylene copolymer
Authors: Liu Yi‐Min , Tong Zai‐Zai , Xu Jun‐Ting , Fu Zhi‐Sheng , Fan Zhi‐Qiang
Published: April 2014

In this work, we reported calcium tetrahydrophthalate as a high efficient β‐nucleating agent (β‐NA) for impact‐resistant polypropylene copolymer (IPC). The relative fraction of the β‐crystal can reach as high as 93.5% when only 0.03% β‐NA is added. The non‐isothermal and isothermal crystallization behaviors, morphology, lamellar structure and mechanical properties of IPCs with various β‐NA contents were studied. During non‐isothermal crystallization, the cooling rate has an important influence on the relative fraction of the β‐crystal, which decreases remarkably as the cooling rate increases. The β‐NA also greatly accelerates crystallization rate of IPC, resulting from both more crystal nuclei and larger Avrami exponent. The small angle X‐ray scattering characterization shows that more amorphous components are included into the inter‐lamellae after addition of β‐NA. Dynamical mechanical analysis (DMA) reveals that the storage modulus at low temperature and the loss factor above 0 °C from the PP component can be enhanced upon addition of β‐NA and reach a maximum at the β‐NA content of 0.05 wt %. Impact test shows that the impact strength of the IPC at 0°C can be improved as much as 40% when the content of calcium tetrahydrophthalate is 0.10 wt %. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40753.
Preconceptional folic acid‐containing supplement use in the national birth defects prevention study
Authors: Khodr Zeina G. , Lupo Philip J. , Agopian A.J. , Canfield Mark A. , Case Amy P. , Carmichael Suzan L. , Mitchell Laura E.
Published: April 2014

Background: Despite public health campaigns encouraging women to take a daily folic acid supplement, the proportion of reproductive age women, in the United States, who comply with this recommendation is less than optimal. The objective of this analysis was to identify predictors of preconceptional folic acid‐containing supplement use to define subgroups of women who may benefit from targeted folic acid campaigns. Methods: This study included 6570 mothers of live born infants from the control population of National Birth Defects Prevention Study (1997–2005). Logistic regression analyses were used to identify predictors of preconceptional folic acid supplementation. A classification and regression tree (CART) analysis was used to define subgroups of women with different patterns of preconceptional folic acid supplementation. Results: Race/ethnicity, education, age at delivery, nativity, employment, income, number of dependents, smoking, and birth control use were significantly associated with preconceptional folic acid‐containing supplement use. Based on a CART analysis, education, race/ethnicity, and age were the most distinguishing factors between women with different preconceptional supplementation patterns. Non‐white women with <4 years of a college education were the least likely to use folic acid‐containing supplements (11%). However, even in the most compliant subgroup (women with ≥4 years of college), only 60% of women supplemented with folic acid. Conclusion: These results demonstrate the need for continued efforts to increase folic acid supplementation among all reproductive aged women. However, the success of such efforts may be improved if maternal characteristics such as education, race/ethnicity, and age, are considered in the development of future interventions. Birth Defects Research (Part A) 100:472–482, 2014. © 2014 Wiley Periodicals, Inc.
Further evidence for FGF16 truncating mutations as the cause of X‐linked recessive fusion of metacarpals 4 / 5
Authors: Jamsheer Aleksander , Śmigiel Robert , Jakubiak Aleksandra , Zemojtel Tomasz , Socha Magdalena , Robinson Peter N. , Mundlos Stefan
Published: April 2014

Background

Metacarpal 4–5 fusion (MF4; MIM#309630) is a rare congenital malformation of the hand characterized by the partial or complete fusion of the fourth and fifth metacarpals. The anomaly occurs as an isolated trait or part of a genetic syndrome. Recently, we have identified FGF16 nonsense mutations as the underlying cause of isolated X‐linked recessive MF4.

Methods

In this report, we provide a detailed clinical description of a sporadic male patient showing MF4 in whom we performed Sanger sequencing of the entire coding sequence of FGF16.

Results

In addition to MF4 symptoms, the patient presented with generalized joint laxity and hypermobility. FGF16 sequencing detected a novel truncating mutation (c.474_477del; p.E158DfsX25) in exon 3 of the gene. A heterozygous mutation was found in a clinically and radiologically unaffected mother of the proband.

Conclusion

Our finding confirms that truncating mutations of FGF16 are causative for X‐linked recessive metacarpal 4–5 fusion. Importantly, the mutation detected in this study was located in last exon of the gene (exon 3), like the only two FGF16 disease‐causing variants identified to date. Thus, all FGF16 mutations known to give rise to this rare skeletal hand malformation are C‐terminal and most probably do not result in a nonsense mediated decay. Additionally, our proband showed mild symptoms of a connective tissue disorder, as some other patients previously reported to have X‐linked MF4. Therefore, we suggest that impaired FGF16 function may also be responsible for connective tissue symptoms in MF4 patients. Birth Defects Research (Part A) 100:314–318, 2014. © 2014 Wiley Periodicals, Inc.
How does the Mediterranean diet promote cardiovascular health? Current progress toward molecular mechanisms
Authors: Corella Dolores , Ordovás José M.
Published: April 2014

Epidemiological evidence supports a health‐promoting effect of the Mediterranean Diet (MedDiet), especially in the prevention of cardiovascular diseases. These cardiovascular benefits have been attributed to a number of components of the MedDiet such as monounsaturated fatty acids, antioxidant vitamins and phytochemicals. However, the underlying mechanisms remain unknown. Likewise, little is known about the genes that define inter‐individual variation in response to the MedDiet, although the TCF7L2 gene is emerging as an illustrative candidate for determining relative risk of cardiovascular events in response to the MedDiet. Moreover, omics technologies are providing evidence supporting potential mechanisms, some of them implicating epigenetics (i.e. microRNAs, methylation), and certain data suggest that some traditional foods could contribute via microRNAs possibly acting as exogenous regulators of gene expression. Future research should aim at increasing and consolidating the nutrigenetic and nutrigenomic knowledge of the MedDiet in order to provide sound, personalized and optimized nutritional recommendations.
A sensitive and selective method for the quantitative analysis of miglitol in rat plasma using unique solid‐phase extraction coupled with liquid chromatography–tandem mass spectrometry
Authors: Mizuno‐Yasuhira Akiko , Kinoshita Kohnosuke , Jingu Shigeji , Yamaguchi Jun‐ichi
Published: April 2014

A sensitive, selective and robust liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method was developed for the quantification of miglitol in rat plasma. The sample preparation procedures involved protein precipitation and unique solid‐phase extraction, which efficiently removed sources of ion suppression and column degradation interference present in the plasma. Chromatographic separation was achieved on an amide column using 10 mmol/L CH3COONH4 and CH3CN:CH3OH (90:10, v/v) as the mobile phase under gradient conditions. Detection was performed using tandem mass spectrometry equipped with an electrospray ionization interface in positive ion mode.The selected reaction monitoring transitions for miglitol and a stable isotope‐labeled internal standard were m/z 208 → m/z 146 and m/z 212 → m/z 176, respectively. The correlation coefficients of the calibration curves ranged from 0.9984 to 0.9993 over a concentration range of 0.5–100 ng/mL plasma. The quantification limit of the proposed method was more than 10 times lower than those of previously reported LC‐MS/MS methods. The novel method was successfully validated and applied to a pharmacokinetic study in rats. Copyright © 2014 John Wiley & Sons, Ltd.
Extraordinary Thermal Stability of an Oligodeoxynucleotide Octamer Constructed from Alternating 7‐Deaza‐7‐iodo guanine and 5‐Iodocytosine Base Pairs – DNA Duplex Stabilization by Halogen Bonds?
Authors: Ramzaeva Natalya , Eickmeier Henning , Rosemeyer Helmut
Published: April 2014

A reinvestigation of the published X‐ray crystal‐structure analyses of 7‐halogenated (Br, I) 8‐aza‐7‐deaza‐2′‐deoxyguanosines Br7c7z8Gd; 1a and I7c7z8Gd, 1b, as well as of the structurally related 7‐deaza‐7‐iodo‐2′‐deoxy‐β‐D‐ribofuranosyladenine (β‐I7c7Ad; 2=6e in Table 1) and its α‐D‐anomer (α‐I7c7Ad; 3) clearly revealed the existence of halogen bonds between corresponding halogen substituents and the adjacent N(3)‐atoms of neighboring nucleoside molecules within the single crystals. These halogen bonds can be rationalized by the presence of a region of positive electrostatic potential, the σ‐hole, on the outermost portion the halogen's surface, while the three unshared pairs of electrons produce a belt of negative electrostatic potential around the central part of the halogen substituent. The N(3) atoms of the halogenated nucleosides carry a partial negative charge. This novel type of bonding between nucleosides was tentatively used to explain the extraordinary high stability of oligodeoxynucleotides constructed from halogenated nucleotide building blocks.
Dynamics of Fatty‐Acid Composition of Neutral Acylglycerols in Maturing Euonymus Fruits
Authors: Sidorov Roman A. , Zhukov Anatoly V. , Pchelkin Vasily P. , Vereshchagin Andrei G. , Tsydendambaev Vladimir D.
Published: April 2014

The dynamics of the fatty‐acid (FA) composition of neutral acylglycerols (NAGs) composed of 1,2,3‐triacyl‐sn‐glycerols (TAGs) and 3‐acetyl‐1,2‐diacyl‐sn‐glycerols (acDAGs) was determined in the fruit seeds and arils of three Euonymus L. species at three stages of their maturity. The NAG composition comprised 29 FAs, linoleic, oleic, palmitic, and α‐linolenic acids being predominant. Noticeable amounts of other FAs, such as lauric, myristic, hexadec‐9‐enoic, stearic, (Z)‐vaccenic, and arachidic acid, etc., could also be present. In the course of maturation, the qualitative composition of major FAs remained nearly unchanged, while the unsaturation index of FAs in seeds and in TAGs, as well as, but to a lesser extent, in arils and in acDAGs, respectively, always decreased. This decline was brought about by a sharp fall of the α‐linolenate level, a decrease of the linoleate content, and a corresponding rise in the oleate content. It is suggested that, in both seeds and arils, both classes of NAGs were formed at the expense of the same FA pool; the quantitative composition of this pool was characteristic of a given fruit part and strongly changed during maturation. The accumulation of TAGs in E. europaeus fruits was accompanied by a conversion of hexadec‐9‐enoic acid into (Z)‐vaccenic acid via the C2‐elongation reaction.
Volatile Compounds in Thymus sect. Teucrioides (Lamiaceae): Intraspecific and Interspecific Diversity, Chemotaxonomic Significance and Exploitation Potential
Authors: Pitarokili Danae , Constantinidis Theophanis , Saitanis Costas , Tzakou Olga
Published: April 2014

Thymus sect. Teucrioides comprises three species, namely, T. hartvigii, T. leucospermus, and T. teucrioides, distributed in Greece and Albania. The volatile constituents of all species of the section were obtained by hydrodistillation and investigated by GC‐FID and GC/MS analyses. Twenty populations were sampled and a total of 103 compounds were identified, representing 98.0–99.9% of the oil compositions. The oils were mainly characterized by high contents of monoterpene hydrocarbons (42.7–92.4%), with the exception of three oils for which oxygenated monoterpenes were the dominating constituents, viz., that of T. hartvigii ssp. macrocalyx, with linalool as main compound (89.2±0.5%), and those of T. hartvigii ssp. hartvigii and of one population of T. teucrioides ssp. candilicus, containing thymol as major component (46.4±3.1 and 38.2±3.9%, resp.). The most common compound in the oils of the 20 populations of the section was p‐cymene. Considerable variation was detected within and among populations, and seven chemotypes were distinguished, i.e., p‐cymene, linalool, p‐cymene/thymol, p‐cymene/γ‐terpinene, p‐cymene/borneol, p‐cymene/γ‐terpinene/borneol, and p‐cymene/linalool chemotypes. Different chemotypes may exist in the same population. Multivariate statistical analyses enabled the segregation of the oils within Thymus sect. Teucrioides into two groups, one consisting of the three subspecies of T. teucrioides and the second comprising the species T. hartvigii and T. leucospermus. A linalool‐rich chemotype, unique within the section, distinguished the oil of T. hartvigii ssp. macrocalyx from all other oils. The high oil content of p‐cymene and the preference for serpentine substrates render T. teucrioides species promising for future exploitation.
Cytotoxic and Apoptosis‐Inducing Activities, and Anti‐Tumor‐Promoting Effects of Cyanogenated and Oxygenated Triterpenes
Authors: Kikuchi Takashi , Ishii Kenta , Ogihara Eri , Zhang Jie , Ukiya Motohiko , Tokuda Harukuni , Iida Takashi , Tanaka Reiko , Akihisa Toshihiro
Published: April 2014

Two of each semisynthetic lanostane‐ and cycloartane‐type triterpenes with a cyano‐enone functionality, i.e., 13 and 18, and 23 and 28, respectively, sixteen of their synthetic intermediates, 9–12, 14–17, 19–22, and 24–27, along with seven semisynthetic oxygenated triterpene acetates, 29–35, and eight natural hydroxy triterpenes, 1–8, were evaluated for their cytotoxic activities against leukemia (HL60), lung (A549), stomach (AZ521), and breast (SK‐BR‐3) cancer cell lines. One natural triterpene, 8, and ten semisynthetic triterpenes, 9, 13, 15, 18, 23, 25, 28, 29, 32, and 33, exhibited potent cytotoxicities against one or more cell lines with IC50 values in the range of 1.4–9.9 μM. Two lanostane‐type triterpenes with a cyano‐enone functionality, 3‐oxolanosta‐1,8,24‐triene‐2‐carbonitrile (13) and 3‐oxolanosta‐1,8‐diene‐2‐carbonitrile (18), induced apoptosis in HL60 cells, as observed by membrane phospholipid exposure in flow cytometry. Western blot analysis showed that 13 and 18 significantly reduced procaspases‐3, ‐8, and ‐9, and increased cleaved caspases‐3, ‐8, and ‐9. These findings indicated that compounds 13 and 18 induced apoptosis in HL60 cells via both the mitochondrial and the death receptor‐mediated pathways. In addition, upon evaluation of the inhibitory effects on EpsteinBarr virus early antigen (EBV‐EA) activation induced with 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA) in Raji cells, seven natural triterpenes, 1–6 and 8, and ten semisynthetic triterpenes, 9, 10, 14, 15, 19, 20, 24, 25, 29, and 30, exhibited inhibitory effects which were higher than that of β‐carotene, a vitamin A precursor studied widely in cancer‐chemoprevention animal models.
Silylation Improves the Photodynamic Activity of Tetraphenylporphyrin Derivatives In Vitro and In Vivo
Authors: Horiuchi Hiroaki , Hosaka Masahiro , Mashio Hiroyuki , Terata Motoki , Ishida Shintaro , Kyushin Soichiro , Okutsu Tetsuo , Takeuchi Toshiyuki , Hiratsuka Hiroshi
Published: April 2014

The effects of silyl and hydrophilic groups on the photodynamic properties of tetraphenylporphyrin (TPP) derivatives have been studied in vitro and in vivo. Silylation led to an improvement in the quantum yield of singlet oxygen sensitization for both sulfo and carboxy derivatives, although the silylation did not affect other photophysical properties. Silylation also improved the cellular uptake efficiency for both sulfo and carboxy derivatives, enhancing the in vitro photodynamic activity of the photosensitizer in U251 human glioma cells. The carboxy derivative (SiTPPC4) was found to show higher cellular uptake efficiency and in vitro photodynamic activity than the corresponding sulfo derivative (SiTPPS4), which indicates that the carboxy group is a more promising hydrophilic group than the sulfo group in the silylated porphyrin. SiTPPC4 was found to show high selective accumulation efficiency in tumors, although almost no tumor selectivity was observed for the nonsilylated porphyrin. The concentration of SiTPPC4 in tumors was 13 times higher than that in muscle 12 h after drug administration. We also studied tumor response after treatment and found that silylation enhanced in vivo photodynamic activity significantly. SiTPPC4 shows higher photodynamic activity than NPe6 with white light irradiation.
Cytotoxicity Profile of Highly Hydrogenated Graphene
Authors: Chng Elaine Lay Khim , Sofer Zdeněk , Pumera Martin
Published: April 2014

Graphene and its graphene‐related counterparts have been considered the future of advanced nanomaterials owing to their exemplary properties. An increase in their potential applications in the biomedical field has led to serious concerns regarding their safety and impact on health. To understand the toxicity profile for a particular type of graphene utilized in a given application, it is important to recognize the differences between the graphene‐related components and correlate their cellular toxicity effects to the attributed physiochemical properties. In this study, the cytoxicity effects of highly hydrogenated graphene (HHG) and its graphene oxide (GO) counterpart on the basis of in vitro toxicological assessments are reported and the effects correlated with the physiochemical properties of the tested nanomaterials. Upon 24 h exposure to the nanomaterials, a dose‐dependent cellular cytotoxic effect was exhibited and the HHG was observed to be more cytotoxic than its GO control. Detailed characterization revealed an extensive CH sp3 network on the carbon backbone of HHG with few oxygen‐containing groups, as opposed to the presence of large amounts of oxygen‐containing groups on the GO. It is therefore hypothesized that the preferential adsorption of micronutrients on the surface of the HHG nanomaterial by means of hydrophobic interactions resulted in a reduction in the bioavailability of nutrients required for cellular viability. The nanotoxicological profile of highly hydrogenated graphene is assessed for the first time in our study, thereby paving the way for further evaluation of the toxicity risks involved with the utilization of various graphene‐related nanomaterials in the real world.
Enantiopure O‐Ethyl Phenylphosphonothioic Acid: A Solvating Agent for the Determination of Enantiomeric Excesses
Authors: Matsumoto Kazushige , Sawayama Jun , Hirao Shotaro , Nishiwaki Nagatoshi , Sugimoto Ryuichi , Saigo Kazuhiko
Published: April 2014

An improved method, which is highly reproducible, was developed for the enantioseparation of racemic O‐ethyl phenylphosphonothioic acid (1a) with brucine by introducing seeding to a supersaturated solution of the diastereomeric salt mixture. The present method gave both diastereomeric salts in high yields with a diastereomeric ratio of >99.5:0.5 upon choosing the crystallization solvent (MeOH for the ((R)-1a salt and MeOH/H2O for the ((S)-1a salt). The enantiopure acid (R)-1a, (S)-1a showed a good chirality recognition ability for not only strong bases, such as amines and amino alcohols, but also weakly basic alcohols and was applicable as a solvating agent to the 1H NMR determination of the enantiomeric excess of chiral amines, amino alcohols, and alcohols, including aliphatic substrates. Chirality 26:614–619, 2014. © 2014 Wiley Periodicals, Inc.
Solubility of Supercritical Fluids in Ionic Liquids
Authors: Türk M. , Metzner René
Published: April 2014

Eine umfangreiche Literaturrecherche zur Löslichkeit von nahe‐ bzw. überkritischen Fluiden (SCF) in Ionischen Flüssigkeiten (IL) zeigte, dass in der Regel die Gaslöslichkeit in den IL mit zunehmendem Druck und sinkender Temperatur zunimmt und dass unpolare, im Gegensatz zu polaren, SCF nur begrenzt in IL löslich sind. Diese Daten konnten mithilfe der Peng‐Robinson‐Zustandsgleichung unter Verwendung der Van‐der‐Waals‐Mischungsregeln mit zwei binären Wechselwirkungsparametern sehr gut beschrieben werden.
UV‐Irradiation of the Antibiotic Sulfathiazole Surprisingly Leads to Former Antituberculotic Promizole
Authors: Spielmeyer Astrid , Heer Myriam , Mohring Siegrun A.I. , Hausmann Heike , Stahl Jessica , Kietzmann Manfred , Dold Sebastian , Spengler Bernhard , Hamscher Gerd
Published: April 2014

Pharmaceuticals are widely distributed in low concentrations in the water compartment. Conventional sewage treatment plants (STP) are not capable to remove pharmaceuticals to the full extent, so alternative methods such as ozonization or photooxidation are tested as additional stage. However, it has been shown that in many cases no complete mineralization is achieved during these processes and transformation products occur. Up to now only little is known about these transformation products in terms of their structure and toxicity. The antibiotic sulfathiazole (STZ) is used in veterinary medicine and it can be detected in different water matrices such as STP effluent or surface water. We tested the ability of photooxidation for degradation of STZ using a medium pressure mercury lamp. LC‐UV showed the formation of several minor compounds and one main transformation product which has been isolated subsequently. Using NMR and high resolution mass spectrometry techniques, we were able to reveal the structure of promizole, an antituberculotic, used in the 1950s. This compound showed a reduced microbial activity in Brilliant Black Reduction Maximum Residue Level test. Furthermore, there was no difference in the effects of promizole when compared to STZ on cell toxicity and cell proliferation in two murine cell lines.
Patterns of symptom burden during radiotherapy or concurrent chemoradiotherapy for head and neck cancer: A prospective analysis using the University of Texas MD Anderson Cancer Center Symptom Inventory‐Head and Neck Module
Authors: Rosenthal David I. , Mendoza Tito R. , Fuller Clifton D. , Hutcheson Katherine A. , Wang X. Shelley , Hanna Ehab Y. , Lu Charles , Garden Adam S. , Morrison William H. , Cleeland Charles S. , Gunn G. Brandon
Published: April 2014

BACKGROUND

A prospective longitudinal study to profile patient‐reported symptoms during radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) for head and neck cancer was performed. The goals were to understand the onset and trajectory of specific symptoms and their severity, identify clusters, and facilitate symptom interventions and clinical trial design.

METHODS

Participants in this questionnaire‐based study received RT or CCRT. They completed the University of Texas MD Anderson Cancer Center Symptom Inventory‐Head and Neck Module before and weekly during treatment. Symptom scores were compared between treatment groups, and hierarchical cluster analysis was used to depict clustering of symptoms at treatment end. Variables believed to predict symptom severity were assessed using a multivariate mixed model.

RESULTS

Among the 149 patients studied, the majority (47%) had oropharyngeal tumors, and nearly one‐half received CCRT. Overall symptom severity (P < .001) and symptom interference (P < .0001) became progressively more severe and were more severe for those receiving CCRT. On multivariate analysis, baseline Eastern Cooperative Oncology Group performance status (P < .001) and receipt of CCRT (P < .04) correlated with higher symptom severity. Fatigue, drowsiness, lack of appetite, problem with mouth/throat mucus, and problem tasting food were more severe for those receiving CCRT. Both local and systemic symptom clusters were identified.

CONCLUSIONS

The findings from this prospective longitudinal study identified a pattern of local and systemic symptoms, symptom clusters, and symptom interference that was temporally distinct and marked by increased magnitude and a shift in individual symptom rank order during the treatment course. These inform clinicians about symptom intervention needs, and are a benchmark for future symptom intervention clinical trials. Cancer 2014;120:1975–1984. © 2014 American Cancer Society.
Robust Stability Criterion for Discrete‐Time Nonlinear Switched Systems with Randomly Occurring Delays via T–S Fuzzy Approach
Authors: Balasubramaniam P. , Jarina Banu L.
Published: April 2014

This article investigates exponential stability of uncertain discrete‐time nonlinear switched systems with parameter uncertainties and randomly occurring delays via Takagi–Sugeno fuzzy approach. The randomness of time‐varying delay is characterized by introducing a Bernoulli stochastic variable that follows certain probability distribution. By adopting the average dwell‐time approach with Lyapunov–Krasovskii functional and using convex reciprocal lemma, delay‐dependent sufficient conditions for exponential stability of the switched fuzzy system are derived in terms of linear matrix inequalities (LMIs), which can be solved readily using any LMI solvers. Finally, illustrative examples are provided to demonstrate the effectiveness of the proposed approach. © 2014 Wiley Periodicals, Inc. Complexity 20: 49–61, 2015
Dense femtocell networks power self‐optimization: an exact potential game approach
Authors: Wang Xidong , Zheng Wei , Lu Zhaoming , Wen Xiangming , Li Wei
Published: April 2014

Femtocell is regarded as a promising technology to enhance indoor coverage and improve network capacity. However, highly dense and self‐organized femtocells in urban environment will result in serious inter‐femtocell interference. To solve this problem, this paper proposes a distributed power self‐optimization scheme for the downlink operation of dense femtocell networks. First, a novel convex pricing mechanism is presented to price the transmit power of femtocells and construct the utility function of femtocells. Then, a noncooperative game framework for power self‐optimization of femtocells in dense femtocell networks is established on the basis of the exact potential game theory, which is demonstrated to converge to a pure and unique Nash equilibrium. Finally, combined with firefly algorithm, an effective power self‐optimization algorithm with guaranteed convergence is proposed to achieve the Nash equilibrium of the proposed game. With practical LTE parameters and a 3GPP dual‐strip femtocell model, simulation results show that the proposed game with convex pricing mechanism increases the femtocell network throughput by 7% and reduces the average transmit power of femtocells by 50% in dense femtocell networks, with respect to the compared schemes. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis and Plasmonic Properties of Core–Shell Bimetallic Silver–Gold Nanoprisms Obtained through an Organometallic Route
Authors: Crespo Julian , Ibarra Alfonso , López‐de‐Luzuriaga José M. , Monge Miguel , Olmos M. Elena
Published: April 2014

Ag–Au core–shell nanoprisms were obtained through the deposition of Au atoms over hexadecylamine‐stabilized Ag nanoparticles through the mild decomposition of an organometallic AuI precursor. The effects of the amount of precursor [Au(C6F5)(tht)] (tht = tetrahydrothiophene) added and the reaction time on the size, shape, and composition of the core–shell Ag–Au nanostructures obtained have been studied by TEM, high‐angle annular dark field/scanning transmission electron microscopy (HAADF‐STEM), EDS, UV/Vis, and 19F NMR spectroscopic analysis. The anisotropic growth of the prismatic metallic shell and its composition has been controlled through the addition of different amounts of AuI precursor, thus leading to a delicate tuning of the plasmonic properties of these nanostructures.
Heterogeneous next‐generation wireless network interference model—and its applications
Authors: Mahmood Nurul H. , Yilmaz Ferkan , Alouini Mohamed‐Slim , Øien Geir E.
Published: April 2014

Next‐generation wireless systems facilitating better utilisation of the scarce radio spectrum have emerged as a response to inefficient and rigid spectrum assignment policies. These are comprised of intelligent radio nodes that opportunistically operate in the radio spectrum of existing primary systems, yet unwanted interference at the primary receivers is unavoidable. In order to design efficient next‐generation systems and to minimise the adverse effect of their interference, it is necessary to realise how the resulting interference impacts the performance of the primary systems. In this work, a generalised framework for the interference analysis of such a next‐generation system is presented where the next‐generation transmitters may transmit randomly with different transmit powers. The analysis is built around a model developed for the statistical representation of the interference at the primary receivers, which is then used to evaluate various performance measures of the primary system. Applications of the derived interference model in designing the next‐generation network system parameters are also demonstrated. Such approach provides a unified and generalised framework, the use of which allows a wide range of performance metrics can be evaluated. Findings of the analytical performance analyses are confirmed through extensive computer‐based Monte‐Carlo simulations. Copyright © 2014 John Wiley & Sons, Ltd.