bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of phytoplankton dynamics in the seasonal and interannual variability of carbon in the subpolar North Atlantic – a modeling study
Authors: Signorini S. R. , Häkkinen S. , Gudmundsson K. , Olsen A. , Omar A. M. , Olafsson J. , Reverdin G. , Henson S. A. , McClain C. R. , Worthen D. L.
Published: May 2012

Abstract. We developed an ecosystem/biogeochemical model system, which includes multiple phytoplankton functional groups and carbon cycle dynamics, and applied it to investigate physical-biological interactions in Icelandic waters. Satellite and in situ data were used to evaluate the model. Surface seasonal cycle amplitudes and biases of key parameters (DIC, TA, pCO2, air-sea CO2 flux, and nutrients) are significantly improved when compared to surface observations by prescribing deep water values and trends, based on available data. The seasonality of the coccolithophore and "other phytoplankton" (diatoms and dinoflagellates) blooms is in general agreement with satellite ocean color products. Nutrient supply, biomass and calcite concentrations are modulated by light and mixed layer depth seasonal cycles. Diatoms are the most abundant phytoplankton, with a large bloom in early spring and a secondary bloom in fall. The diatom bloom is followed by blooms of dinoflagellates and coccolithophores. The effect of biological changes on the seasonal variability of the surface ocean pCO2 is nearly twice the temperature effect, in agreement with previous studies. The inclusion of multiple phytoplankton functional groups in the model played a major role in the accurate representation of CO2 uptake by biology. For instance, at the peak of the bloom, the exclusion of coccolithophores causes an increase in alkalinity of up to 4 μmol kg−1 with a corresponding increase in DIC of up to 16 μmol kg−1. During the peak of the bloom in summer, the net effect of the absence of the coccolithophores bloom is an increase in pCO2 of more than 20 μatm and a reduction of atmospheric CO2 uptake of more than 6 mmol m−2 d−1. On average, the impact of coccolithophores is an increase of air-sea CO2 flux of about 27%. Considering the areal extent of the bloom from satellite images within the Irminger and Icelandic Basins, this reduction translates into an annual mean of nearly 1500 tonnes C yr−1.
Modular Palladium Bipyrazoles for the Isomerization of Allylbenzenes – Mechanistic Considerations and Insights into Catalyst Design and Activity, Role of Solvent, and Additive Effects
Authors: Spallek Markus J. , Stockinger Skrollan , Goddard Richard , Trapp Oliver
Published: May 2012

The catalytic activity of novel bidentate N,N‐chelated palladium complexes derived from electron excessive, backbone fused 3,3′‐bipyrazoles in the selective isomerization of terminal arylpropenoids and 1‐alkenes is described. The catalysts are easily modified by appropriate wing tip substitution, while maintaining the same bulky, rigid unreactive aliphatic backbone. Eleven novel palladium complexes with different electronic and steric properties were investigated. Their performance in the palladium(II)‐catalyzed isomerization of a series of substituted allylbenzenes was evaluated in terms of electronic as well as steric effects. Besides the clear finding of a general trend towards higher catalyst activity with more electron‐donating properties of the coordinated N,N‐bidentate ligands, we found that the catalytic process strongly depends on the choice of solvents and additives. Extensive solvent screening revealed that reactions run best in a 2:1 toluene‐methanol mixture, with the alcohol employed being a crucial factor in terms of electronic and steric factors. A reaction mechanism involving a hydride addition–elimination mechanism starting with a palladium hydride species generated in situ in alcoholic solutions, as corroborated by experiments using deuterium labeled allylbenzene, seems to be most likely. The proposed mechanism is also supported by the observed reaction rate orders of κobs[cat.]≈1 (0.94), κobs [substrate]=0.20→1.0 (t→∞) and κobs [methanol]=−0.51 for the isomerization of allylbenzene. Furthermore, the influence of acid and base, as well as the role of the halide coordinated to the catalyst, are discussed. The system catalyzes the isomerization of allylbenzenes very efficiently yielding high E:Z selectivities under very mild conditions (room temperature) and at low catalyst loadings of 1 mol% palladium even in unpurified solvents. The integrity and stability of the catalyst system were confirmed by multiple addition reaction cycles, successive filtration and isolation experiments, and the lack of palladium black formation.
Teleparallel gauge theory of gravity
Authors: Maluf J.W. , Faria F.F.
Published: May 2012

In this work a tetrad theory of gravity, invariant under conformal transformations, is investigated. The action of the theory is similar to the action of Maxwell's electromagnetism. The role of the electromagnetic gauge potential is played by the trace of the torsion tensor of the Weitzenböck spacetime. It is shown that all static, spherically symmetric space‐times, are solutions of the vacuum field equations. However, by fixing the gauge in the linearized form of the vacuum field equations, the usual Newtonian limit for the gravitational field is obtained.
Comparative study of the influence of active groups of chitosan derivatives on antifungal activity
Authors: Guo Zhanyong , Ren Jianming , Dong Fang , Wang Gang , Li Pengcheng
Published: May 2012

In this study, series of chitosan derivatives containing active groups were synthesized and evaluated for their antifungal activity against three crop‐threatening fungi, Fusarium oxysporum. f. sp. Vasinfectum, Alternaria solani, and Valsa mali. Schiff bases of carboxymethyl chitosan (As: 2‐(2‐hydroxy‐5‐nitrobenzylideneamino)‐6‐carboxymethyl chitosan; Bs: 2‐(2‐hydroxyl‐5‐chlorobenzaldimino)‐6‐carboxymethyl chitosan), N‐substituted carboxymethyl chitosan (An: 2‐(2‐hydroxyl‐5‐nitrobenzylamino)‐6‐carboxymethyl chitosan; Bn: 2‐(2‐hydroxyl‐5‐chlorobenzylamino)‐6‐carboxymethyl chitosan) and 2‐urea‐carboxymethyl chitosan (Au: 2‐(2‐nitrophenylurea)‐6‐carboxymethyl chitosan; Bu: 2‐(2‐chlorophenylurea)‐6‐carboxymethyl chitosan) were synthesized, and their antifungal activity was comparatively studied by hypha measurement in vitro, respectively. Results obtained from this study revealed that the active groups combined with Schiff bases functional groups (CN) could strengthen the antifungal activity most effectively among the compounds studied in this work. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effects of two types of clay on physical and mechanical properties of poly(lactic acid)/wood flour composites at various wood flour contents
Authors: Liu Ru , Cao Jinzhen , Luo Shupin , Wang Xing
Published: May 2012

To investigate the effects of two types of clay, namely, Na‐montmorillonite (Na‐MMT) and organic‐montmorillonite (OMMT), on poly(lactic acid) (PLA)/wood flour (WF) composites, some physical and mechanical properties including the water sorption, thickness swelling, flexural modulus of rupture (MOR), and modulus of elasticity (MOE) of PLA/WF composites at different WF contents of 0, 20, 40, and 60 wt% were tested in this study. The results showed that: (1) the 24 h water uptake and thickness swelling increased and the flexural MOR and crystallinity decreased with the increasing WF content, whereas the flexural MOE of the composites increased with WF content up to 40 wt% but decreased sharply at WF content of 60 wt%; (2) the addition of Na‐MMT slightly increased the 24 h water uptake as well as the thickness swelling rate below 40 wt%, whereas OMMT reduced the thickness swelling at higher WF contents (40, 60 wt%) although it showed little effect on 24 h water uptake; (3) both Na‐MMT and OMMT could improve the flexural MOR and MOE of PLA/WF composite at WF contents below 40 wt%, and OMMT resulted in more obvious improvement than Na‐MMT. However, they both showed negative effect at WF content of 60 wt%; (4) XRD and FT‐Raman analysis suggested that clays would be attached more on the surface of the WF rather than diffused in the PLA matrix at a higher WF content (60 wt%); (5) SEM analysis proved that the interfacial adhesion of PLA and WF became poorer at WF content above 40 wt%, whereas it could be improved by OMMT modified. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Physical and thermal mechanical properties of corn starch/LDPE composites
Authors: Oromiehie A. R. , lari T. Taherzadeh , Rabiee A.
Published: May 2012

The potential of biodegradable polymers has long been recognized. In this work, composites of low density polyethylene (LDPE) and low density polyethylene/thermoplastic starch (LDPE/TPS) at different ratios of TPS (40%‐60% w/w) were prepared in internal mixer. Polyethylene‐grafted maleic anhydride (PE‐g‐MA) at 3 wt % was used as coupling agent. Chemical reactions between functional groups of composite components were studied and confirmed by Fourier transforms infrared (FTIR) spectroscopy. The morphology of film surfaces was studied using scanning electron microscopy. The physical, mechanical, and dynamic‐mechanical thermal analyses of LDPE/TPS composites were evaluated. The FTIR results showed transmission peak at 1642 cm−1, which is the result of chemical reaction between the hydroxyl groups of starch and anhydride groups of coupling agent. This verifies the presence of the carboxylate group due to the formation of ester bonding. The results showed that the water absorption and density of composite films increased by increasing the starch content in LDPE/TPS composites. The tensile strength and elongation at break decreased by increasing the starch level in the composites, but the young's modulus increased. The morphological studies showed that the biodegradability of composites increased by increasing the starch content and the results was confirmed by weight loss in buring the samples in wet soil during time intervals. The dynamic mechanical thermal analyzer thermograms showed that there are two relaxation temperature peaks. The amplitude of peaks increased by increasing the starch content from 40 to 60% probably due to increasing amorphous phase of composite. The starch was uniformly distributed throughout the LDPE polymer matrix and compatible and biodegradable composites were formed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of UV absorbers and hindered amine light stabilizers on the photodegradation of ethylene–octene copolymer
Authors: Liu Zhongyang , Chen Shuangjun , Zhang Jun
Published: May 2012

The photodegradation behavior of ethylene–octene copolymer (EOC) and EOC stabilized with UV stabilizers (Tinuvin 326, Chimassorb 81, Tinuvin 770 and Chimassorb 944) were investigated by the digital photography, color difference, gel content, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and mechanical tests. The results revealed that EOC exhibited a very poor photostability, whose performances were sharply reduced with increasing the irradiation time. The photodegradation products consisted of the carbonyl, hydroxyl and vinyl groups. The additives all showed an excellent photostabilizing effect, which effectively inhibited the gel formation and the chain photooxidation. The photostabilizing efficiency of these UV stabilizers could be ranked as Tinuvin 326 < Chimassorb 81 < Tinuvin 770 and Chimassorb 944. The secondary crystallization behavior was strongly affected by the annealing and chain scission. The chain scission, rather than the annealing, played a greater role in the secondary crystallization of the chain segments. And the serious chain scission could improve the mobility of the chain segments, which sharply promoted their crystallizability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Simple Analogues of Qinghaosu (Artemisinin)
Authors: Li Yun , Hao Hong‐Dong , Wittlin Sergio , Wu Yikang
Published: May 2012

A series of 1,2,4‐trioxanes were synthesized in which the key peroxy bonds were installed through a molybdenum‐catalyzed perhydrolysis of the epoxy rings. A core structure was identified that may serve as a promising lead structure for further investigations because of its high antimalarial activity (comparable to that of artesunate and chloroquine), apparent potential for scale‐up and derivatization, and facile monitoring/tracing by using UV light.
Emotions, Risk Perceptions, and Precautionary Behavior Under the Threat of Terror Attacks: A Field Study Among Israeli College Students
Authors: Rosenboim Mosi , Benzion Uri , Shahrabani Shosh , Shavit Tal
Published: May 2012

The current study uses the unique data from a natural experiment conducted in a college located in southern Israel that was exposed to rocket attacks in 2008. The study examines the relationships between the negative emotions, the perceptions of risk to oneself, the precautionary actions, and the intentions of 290 students who were exposed to terror attacks while on campus. In addition, we compared the emotions, the risk perceptions, and the precautionary behavior between the two groups: those who lived within the range of the rockets and were also exposed to rocket attacks at home and those who lived outside the range of the rockets. The results show that the risk perceptions were affected mainly by the emotion of fear while the students were on campus. In particular, fearful people became more pessimistic about their general and personal risks from terror but not about routine risks. The results also reveal that those who lived outside the rocket area (and had less or no experience with terror attacks) were more likely to take precautionary actions during their stay in the campus and were more pessimistic about continuing their studies in college in the coming year than those living in the area, who had more experience with terror attacks. Copyright © 2011 John Wiley & Sons, Ltd.
Discovery of Small‐Molecule Interleukin‐2 Inhibitors from a DNA‐Encoded Chemical Library
Authors: Leimbacher Markus , Zhang Yixin , Mannocci Luca , Stravs Michael , Geppert Tim , Scheuermann Jörg , Schneider Gisbert , Neri Dario
Published: May 2012

Libraries of chemical compounds individually coupled to encoding DNA tags (DNA‐encoded chemical libraries) hold promise to facilitate exceptionally efficient ligand discovery. We constructed a high‐quality DNA‐encoded chemical library comprising 30 000 drug‐like compounds; this was screened in 170 different affinity capture experiments. High‐throughput sequencing allowed the evaluation of 120 million DNA codes for a systematic analysis of selection strategies and statistically robust identification of binding molecules. Selections performed against the tumor‐associated antigen carbonic anhydrase IX (CA IX) and the pro‐inflammatory cytokine interleukin‐2 (IL‐2) yielded potent inhibitors with exquisite target specificity. The binding mode of the revealed pharmacophore against IL‐2 was confirmed by molecular docking. Our findings suggest that DNA‐encoded chemical libraries allow the facile identification of drug‐like ligands principally to any protein of choice, including molecules capable of disrupting high‐affinity protein–protein interactions.
Influence of Drying and Calcination on Remaining Amount and Immobile Character of Titanium on Titanium‐pillared Montmorillonite
Authors: Zhao Chuan , Wang Xiaoqun , Du Shanyi
Published: May 2012

Remove of titanium (Ti) from titanium‐pillared montmorillont (TIPM) is not expected during its application as adsorbent and photocatalyst, etc. But studies on immobilization of Ti on TIPM are seldom reported. In this work, TIPM was synthesized from TiCl4 and Na+‐montmorillont (Na+‐MMT). Then the prepared TIPM was heated at different temperatures (100, 240 and 450°C) to yield three TIPM samples (TIPM1, TIPM2, and TIPM3). Inductively coupled plasma optical emission spectrometer (ICP‐OES) was used to determine the effect of heating temperature on the remaining amount of Ti on TIPMs. A two‐step treatment method which is often used in the pretreatment and application of TIPM was developed to investigate the immobile character of Ti on TIPMs. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), N2 adsorption/desorption isotherm, thermogravimetric analysis and differential scanning calorimetry (TG‐DSC) were also used to characterize TIPMs before and after the treatment. The results show that with an increase in heating temperature, the amount of Ti species remained on TIPM decreases gradually and Ti immobilization is strengthened on TIPM. For TIPM3, less than 2% Ti is removed from TIPM3 after the treatment required to simulate the practical conditions of TIPM in its application, while those of TIPM1 and TIPM2 are 6.6% and 8.4%, respectively. The reason may be that when TIPM is heated, Ti species intercalated into MMT become chemically bonded with the framework of MMT and partially migrate into the layer structure, which make Ti immobile on TIPM firmly during the treatment process.
Smoking Status on Outcomes After Percutaneous Coronary Intervention
Authors: Chen Tao , Li Wei , Wang Yang , Xu Bo , Guo Jin
Published: May 2012

Background:

The effect of smoking on prognosis among patients undergoing percutaneous coronary intervention (PCI) is controversial, and data on the importance of smoking cessation or reductions were lacking.

Hypothesis:

Smoking cessation or reductions could reduce the risk of adverse outcomes in patient after PCI.

Methods:

There were 19 506 consecutive patients who had undergone successful PCI between April 2004 and January 2010 followed. Extensive data, including self‐reported smoking habits, were obtained at baseline and during follow‐up.

Results:

Compared with post‐PCI quitters and persistent smokers, the nonsmokers and pre‐PCI quitters were older and had a higher prevalence of comorbid factors such as hypertension and impaired left ventricle function. The adjusted hazard ratios for mortality were 2.52 (95% confidence interval [CI]: 1.92–3.30) for nonsmokers, 0.52 (95% CI: 0.32–0.84) for pre‐PCI quitters, and 0.11 (95% CI: 0.06–0.22) for post‐PCI quitters, compared to persistent smokers. With respect to additional revascularizations, a higher risk was observed among the quitters (1.70 [95% CI: 1.40–2.08] for pre‐PCI quitters and 1.59 [95% CI: 1.36–1.85] for post‐PCI quitters) as well as the nonsmokers (1.40 [95% CI: 1.20–1.64]). Among persistent smokers, each reduction of 5 cigarettes/day was associated with a 72% decline in mortality risk (P < 0.001) but did not reach statistical significant for repeated revascularizations (0.80 [95% CI: 0.46–1.37], P = 0.4132).

Conclusions:

Despite a higher risk of revascularization, the cessation of smoking either before or after PCI is beneficial in all‐cause mortality. The apparent smoker's paradox may be explained by the differences in baseline risk or the reduced sensitivity to adverse outcomes as well as the reluctance to seek medical help among smokers.

This study received an unrestricted grant from Pfizer Investment Co., China. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
Development of multiplex PCR system with 15 X‐STR loci and genetic analysis in three nationality populations from China
Authors: Liu Qiu‐Ling , Lu De‐Jian , Quan Li , Chen Ye‐Fei , Shen Min , Zhao Hu
Published: May 2012

The aim of this study is to develop a new multiplex PCR system that simultaneously amplifies the 15 X‐chromosome short tandem repeats (X‐STRs) loci in the same PCR reaction, and to obtain the 15 X‐STR loci database in three nationality populations from China. This multiplex system includes DXS7133, DXS6801, DXS981, DXS6809, DXS7424, DXS6789, DXS9898, DXS7132, GATA165B12, DXS101, DXS10075, DXS6800, GATA31E08, DXS10074, and DXS10079, which were successfully analyzed on 1251 DNA samples (670 males and 581 females) from Guangdong Han population, Xinjiang Uigur and Kazakh. The allele frequencies and mutation rates of the 15 loci were investigated, and the allele frequency distribution among different populations was compared. A total of 6–17 alleles for each locus were observed and altogether 170 alleles for all the selected loci were found. Thirteen cases with mutation of the above loci were detected in 11 850 meioses. Pairwise comparisons of the allele frequencies distribution showed significant differences in most loci among different populations. The results indicate that this multiplex system may provide high polymorphism information for kinship testing and relationship investigations, and it is necessary to gain allele frequency and mutation rate of different population for forensic application.
Nanotube‐grafted polyacrylamide hydrogels for electrophoretic protein separation
Authors: Gunavadhi Murugappan , Maria Lourdusamy Arul Antony , Chamundeswari Vidya N. , Parthasarathy Meera
Published: May 2012

Multiwalled carbon nanotube‐modified polyacrylamide gels have been employed for the electrophoretic separation of proteins. Two approaches are compared in this investigation, one using nanotubes only as fillers inside the gel matrix and the other using nanotubes as catalyst for polymerization of acrylamide. In both the cases, polymerization of acryl‐amide/bisacrylamide has been carried out in situ in the presence of nanotubes dispersed in the gel buffer containing monomer and cross‐linker. In the former case, initiator and catalyst have been added after ultrasonication of nanotubes in the gel buffer mixture where the nanotubes play the role of filler. On the other hand, the second approach precludes use of catalyst and involves addition of initiator alone during ultrasonication of nanotubes in the gel buffer containing monomer and cross‐linker, which leads to the formation of nanotube‐grafted gel after 25 min. When nanotubes are used as a catalyst instead of N,N,N′,N′‐tetramethylethylenediamine, pore size distribution of the gel matrix and linearity of molecular weight calibration plots are found to be improved. In addition, other issues associated with the use of an external catalyst like handling the moisture‐sensitive and corrosive reagent and associated irreproducibility are addressed in this approach.
Using electrophoretic exclusion to manipulate small molecules and particles on a microdevice
Authors: Kenyon Stacy M. , Weiss Noah G. , Hayes Mark A.
Published: May 2012

Electrophoretic exclusion, a novel separations technique that differentiates species in bulk solution using the opposing forces of electrophoretic velocity and hydrodynamic flow, has been adapted to a microscale device. Proof‐of‐principle experiments indicate that the device was able to exclude small particles (1 μm polystyrene microspheres) and fluorescent dye molecules (rhodamine 123) from the entrance of a channel. Additionally, differentiation of the rhodamine 123 and polystyrene spheres was demonstrated. The current studies focus on the direct observation of the electrophoretic exclusion behavior on a microchip.
Optimization of large gel 2D electrophoresis for proteomic studies of skeletal muscle
Authors: Reed Patrick W. , Densmore Allison , Bloch Robert J.
Published: May 2012

We describe improved methods for large format, two‐dimensional gel electrophoresis (2DE) that improve protein solubility and recovery, minimize proteolysis, and reduce the loss of resolution due to contaminants and manipulations of the gels, and thus enhance quantitative analysis of protein spots. Key modifications are: (i) the use of 7 M urea and 2 M thiourea, instead of 9 M urea, in sample preparation and in the tops of the gel tubes; (ii) standardized deionization of all solutions containing urea with a mixed bed ion exchange resin and removal of urea from the electrode solutions; and (iii) use of a new gel tank and cooling device that eliminate the need to run two separating gels in the SDS dimension. These changes make 2DE analysis more reproducible and sensitive, with minimal artifacts. Application of this method to the soluble fraction of muscle tissues reliably resolves ∼1800 protein spots in adult human skeletal muscle and over 2800 spots in myotubes.
Microchip electrophoresis of DNA following preconcentration at photopatterned gel membranes
Authors: Meagher Robert J. , Thaitrong Numrin
Published: May 2012

Rapid separation of nucleic acids by microchip electrophoresis could streamline many biological applications, but conventional chip injection strategies offer limited sample stacking, and thus limited sensitivity of detection. We demonstrate the use of photopatterned polyacrylamide membranes in a glass microfluidic device, with or without fixed negative charges, for preconcentration of double‐stranded DNA prior to electrophoretic separation to enhance detection limits. We compared performance of the two membrane formulations (neutral or negatively charged) as a function of DNA fragment size, preconcentration time, and preconcentration field strength, with the intent of optimizing preconcentration performance without degrading the subsequent electrophoretic separation. Little size‐dependent bias was observed for either membrane formulation when concentrating dsDNA > 100 bp in length, while the negatively charged membrane more effectively blocks passage of single‐stranded oligonucleotide DNA (20‐mer ssDNA). Baseline resolution of a six‐band dye‐labeled ladder with fragments 100–2000 bp in size was obtained in <120 s of separation time, with peak efficiencies in the range of 2000–15 000 plates/cm, and detection limits as low as 1 pM per single dye‐labeled fragment. The degree of preconcentration is tunable by at least 49‐fold, although the efficiency of preconcentration was found to have diminishing returns at high field and/or long times. The neutral membrane was found to be more robust than the negatively charged membrane, with approximately 2.5‐fold larger peak area during the subsequent separation, and less decrease in resolution upon increasing the preconcentration field strength.
De Liliifloris Notulae 9. The only hitherto known Spiloxene species (Hypoxidaceae) from Namibia is a new species, Spiloxene etesionamibensis, and a new Spiloxene species from Namaqualand (Northern Cape), S. namaquana
Authors: Müller‐Doblies Ute , Ackermann Markus , Weigend Maximilian , Müller‐Doblies Dietrich
Published: May 2012

The only Namibian species of Spiloxene is described and illustrated by drawings and photos as Spiloxene etesionamibensis U.Müll.‐Doblies, Mark.Ackermann, Weigend &. D.Müll.‐Doblies. It was hitherto misinterpreted as Spiloxene scullyi (Baker) Garside in Sölch & Roessler (1969) in Merxmüller's Prodromus einer Flora von Südwestafrika, but its closest ally is S. flaccida (Nel) Garside, found in the Western and the Eastern Cape. Spiloxene etesionamibensis, which was found independently by Giess & Merxmüller and by Müller‐Doblies, is only known from two or three independent collections from a single locality. S. scullyi is no longer known from Namibia.

In addition to the eight Spiloxene species already known from the Northern Cape Spiloxene namaquana U.Müll.‐Doblies, Mark.Ackermann, Weigend & D.Müll.‐Doblies is described and illustrated by drawings and photos. Its closest ally is Spiloxene trifurcillata (Nel) Fourc. from the Eastern Cape.

For Spiloxene namaquana the morphological analysis of the branching pattern of an annual shoot taken in 1988 in the field is evaluated by a longitudinal and a horizontal diagram with explanatory remarks. The unusual innovation system of extreme anisoiteration is discussed.

On Map 1 the quarter degree squares of the type localities (± only known localities) of both species is given. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of age on genetic influence on bone loss over 17 years in women: The Healthy Ageing Twin Study (HATS)
Authors: Moayyeri Alireza , Hammond Christopher J , Hart Deborah J , Spector Timothy D
Published: May 2012

The rate of bone loss varies across the aging period via multiple complex mechanisms. Therefore, the role of genetic factors on bone loss may also change similarly. In this study, we investigated the effect of age on the genetic component of bone loss in a large twin-based longitudinal study. During 17 years of follow-up in TwinsUK and Healthy Ageing Twin Study (HATS), 15,491 hip and lumbar spine dual-energy X-ray absorptiometry (DXA) scans were performed in 7056 twins. Out of these subjects, 2716 female twins aged >35 years with at least two scans separated for >4 years (mean follow-up 9.7 years) were included in this analysis. We used a mixed-effects random-coefficients regression model to predict hip and spine bone mineral density (BMD) values for exact ages of 40, 45, 50, 55, 60, 65, 70, 75, and 80 years, with adjustment for baseline age, weight, height, and duration of hormone replacement therapy. We then estimated heritability of the changes in BMD measures between these age ranges. Heritability estimates for cross-sectional hip and spine BMD were high (ranging between 69% and 88%) at different ages. Heritability of change of BMD was lower and more variable, generally ranging from 0% to 40% for hip and 0% to 70% for spine; between age 40 and 45 years genetic factors explained 39.9% (95% confidence interval [CI], 25%–53%) of variance of BMD loss for total hip, 46.4% (95% CI, 32%–58%) for femoral neck, and 69.5% (95% CI, 59%–77%) for lumbar spine. These estimates decreased with increasing age, and there appeared to be no heritability of BMD changes after the age of 65 years. There was some evidence at the spine for shared genetic effects between cross-sectional and longitudinal BMD. Whereas genetic factors appear to have an important role in bone loss in early postmenopausal women, nongenetic mechanisms become more important determinants of bone loss with advanced age. © 2012 American Society for Bone and Mineral Research.
The Role of Posttraumatic Stress and Problem Alcohol Involvement in University Academic Performance
Authors: Bachrach Rachel L. , Read Jennifer P.
Published: May 2012

Objective

The present study examines how Posttraumatic Stress Disorder (PTSD) during the first year of university affects academic performance and whether alcohol behavior mediates the relationship between PTSD and poor academic outcomes.

Method

University students (N = 1,002; 65% female; Mage = 18.11) completed a baseline web survey, and 5 subsequent surveys throughout freshman year assessing variables of interest.

Results

Mediation analyses were not significant; however, students who developed PTSD had a lower grade point average and experienced more alcohol consequences by the end of freshman year. Unremitted PTSD and alcohol consequences were associated with leaving university by year's end.

Conclusions

Findings suggest that assessment of trauma‐related symptoms and alcohol behavior might benefit interventions aimed at students with academic difficulties. © 2012 Wiley Periodicals, Inc. J. Clin. Psychol. 68:843‐859, 2012
Prenatal sonographic diagnosis of mature renal teratoma: A case report
Authors: Yang Fan , Yang Taizhu , Luo Hong , Chen Huijiao , Yao Jin , Song Bin
Published: May 2012

Renal teratoma is an extremely rare condition found in adolescents and young adults. Here, we report a case in which renal teratoma was diagnosed by fetal ultrasound examination. To our knowledge, this is the first report to describe the imaging manifestation of renal teratoma in prenatal diagnosis.© 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013
Pneumopericardium diagnosis by point‐of‐care ultrasonography
Authors: Bobbia Xavier , Claret Pierre Géraud , Muller Laurent , de La Coussaye Jean Emmanuel
Published: May 2012

Focused cardiac ultrasound by the emergency physician has become a fundamental tool to expedite the diagnostic evaluation of the patient at bedside. We report the case of a patient admitted to the emergency department for respiratory distress. He was examined by an emergency physician who performed a bedside echocardiography. Bright spots were seen rapidly moving along the pericardial layer during diastole with comet‐tail artifacts extending across the whole image of the heart and disappearing during systole, suggesting pneumopericardium. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2013
Sphingosine 1‐phosphate‐primed astrocytes enhance differentiation of neuronal progenitor cells
Authors: Spohr Tânia Cristina Leite de Sampaio e , Dezonne Rômulo Sperduto , Nones Jader , dos Santos Souza Cleide , Einicker‐Lamas Marcelo , Gomes Flávia Carvalho Alcântara , Rehen Stevens Kastrup
Published: May 2012

Sphingosine 1‐phosphate (S1P) is a bioactive signaling lysophospholipid. Effects of S1P on proliferation, survival, migration, and differentiation have already been described; however, its role as a mediator of interactions between neurons and glial cells has been poorly explored. Here we describe effects of S1P, via the activation of its receptors in astrocytes, on the differentiation of neural progenitor cells (NPC) derived from either embryonic stem cells or the developing cerebral cortex. S1P added directly to NPC induced their differentiation, but S1P‐primed astrocytes were able to promote even more pronounced changes in maturation, neurite outgrowth, and arborization in NPC. An increase in laminin by astrocytes was observed after S1P treatment. The effects of S1P‐primed astrocytes on neural precursor cells were abrogated by antibodies against laminin. Together, our data indicate that S1P‐treated astrocytes are able to induce neuronal differentiation of NPC by increasing the levels of laminin. These results implicate S1P signaling pathways as new targets for understanding neuroglial interactions within the central nervous system. © 2012 Wiley Periodicals, Inc.
Effective separation of dopamine from bananas on 2‐(3,4‐dimethoxyphenyl)ethylamine imprinted polymer
Authors: Luliński Piotr , Maciejewska Dorota
Published: May 2012

A 2‐(3,4‐dimethoxyphenyl)ethylamine imprinted polymer (MIPpt) was prepared via the precipitation polymerization together with a nonimprinted polymer (NIP). The morphology of particles was investigated by scanning electron microscopy and the specific surface areas were estimated by methylene blue adsorption (60.5 ± 3.5 and 36.9 ± 1.2 m2/g for MIPpt and NIP, respectively). The binding experiments were performed to determine the binding capacity of MIPpt/NIP particles toward dopamine. Next, the effects of solvents on loading, washing, and eluting steps were examined on solid‐phase extraction (SPE). Methanol–water 85:15 v/v (loading step), methanol (washing step), and 0.04 M aqueous ammonium acetate–methanol 30:70 v/v (eluting step) were selected as the most effective systems. Described SPE protocol was successfully applied for separation of dopamine on 2‐(3,4‐dimethoxyphenyl)ethylamine imprinted particles. Finally, the molecularly imprinted polymer was used for determination of dopamine in spiked banana extract. The total recovery of dopamine from MIPpt was equal to 88.5 ± 4.6%, but from NIP was only 12.8 ± 2.3%. The developed material and method were demonstrated to be applicable for the separation of dopamine from bananas. The commercial sorbent C18 was not suitable to such application.
Full automatic determination of chlorophenols in water using solid‐phase microextraction/on‐fiber derivatization and gas chromatography‐mass spectrometry
Authors: Wang Xiaowei , Chen Ruohong , Luan Tiangang , Lin Li , Zou Shichun , Yang Qingshu
Published: May 2012

A fully automated combination of solid‐phase microextraction and on‐fiber derivatization coupled with gas chromatography‐mass spectrometry was developed to determine 17 chlorophenols in aqueous samples. Optimal parameters for the automated process, such as fiber coating (polyacrylate), derivatization reagent (N,O‐bis(trimethylsilyl) trifluoroacetamide), extraction time (60 min), derivatization time (5 min), incubation temperature (35°C), sample pH (3), and ionic strength (300 g L−1 of NaCl), as well as desorption time (5 min) and desorption temperature (270°C) were established. The whole procedure took only 90 min and was performed automatically. The shortcomings of silylation derivatives, like incompleteness and instability, were overcome by using solid‐phase microextraction on‐fiber silylation in this study. The results from both pure water and river water samples showed that the method had a good linearity (r2 = 0.9993–1.0000), ranging from 0.01 to 100 μg L−1. The related standard deviations were between 3.6 and 10.0%. The limits of detections and qualifications ranged from 0.03 to 3.11 ng L−1 and 0.09 to 10.4 ng L−1 for the CPs, respectively. The proposed method is superior to traditional solid phase extraction procedure.
Different mechanisms underlying changes in excitability of peripheral nerve sensory and motor axons in multiple sclerosis
Authors: Ng Karl , Howells James , Pollard John D. , Burke David
Published: May 2012

Introduction: Subtle involvement of peripheral nerves may occur in multiple sclerosis. Motor excitability studies have suggested upregulation of slow K+ currents, probably secondary to altered motoneuron properties resulting from the central lesion. This study concentrates on sensory axons. Methods: Excitability of median nerve axons at the wrist was studied in 26 patients. Results: Sensory recordings were possible in 22 patients, and reduced superexcitability was the sole abnormality. There was no evidence for changes in membrane potential or demyelination. The decrease was significant in patients taking immunomodulatory therapy. These findings could be reproduced in a computer model by changing the gating of fast K+ channels. Motor axon findings were consistent with previously reported increased slow K+ current. Conclusions: The sensory findings differ from motor findings. They can be explained by a humoral factor, possibly cytokines, which can penetrate the paranode and have been documented to alter the gating of K+ channels. Muscle Nerve, 2013
Photovoltaic module simulation by neural networks using solar spectral distribution
Authors: Piliougine Michel , Elizondo David , Mora‐López Llanos , de‐Cardona Mariano Sidrach‐
Published: May 2012

A novel methodology based on artificial neural networks is proposed as an alternative to algebraic and numerical procedures to determine the I‐V curve of a module under different conditions. Although there are methods that use neural networks for approximating the I‐V curve, this is the first time that the measurement of the spectrum is incorporated as an input. In addition, a suitable selection of the training samples used to build the model is fundamental in order to get an accurate approximation. This is why a training sample selection based on a Kohonen self‐organizing map is performed in this paper instead of a random selection. With the use of this preliminary step, the performance of the network trained with spectral information improves over the one without spectral information. Copyright © 2012 John Wiley & Sons, Ltd.
On the Elastic Modulus of Powders
Authors: Nysaeter Trude O. , Enstad Gisle G.
Published: May 2012

For the design of silos and similar equipment for storage, handling and processing of particulate materials, a thorough understanding of the mechanical behaviour of powders is of great importance. Whereas strength properties of powders have been investigated by many workers, the elastic behaviour at small deformations has been much less in focus. In that respect, a simple preliminary theory of uniaxial elasticity has been derived for particles, based on a simple system of spherical and monosized particles of a homogenous and elastically isotropic material. The equation σ = Epϵel2 gives the relationship between stress, elastic modulus and elastic deformation for the unloading of a given powder at a specific consolidation stress/ compression level. Comparisons with experimental results of real powders in a uniaxial tester show surprisingly good agreement in many cases. The equation seems to describe the elasticity of powders fairly well, although it is only a preliminary derivation based on simple considerations.
Fractional exhaled nitric oxide in healthy non‐asthmatic 7‐year olds and prenatal exposure to polycyclic aromatic hydrocarbons: Nested regression analysis
Authors: Jedrychowski Wieslaw , Maugeri Umberto , Mroz Elzbieta , Flak Elzbieta , Rembiasz Maria , Jacek Ryszard , Sowa Agata
Published: May 2012

The main goal of the study was to assess possible association between transplacental exposure to genotoxic PAH compounds assessed by the cord blood PAH–DNA adducts and fractional exhaled nitric oxide (FeNO) measured in healthy non‐asthmatic children at the age of 7 years. The subjects included the subsample of 89 children who took part in the ongoing population based birth cohort study in Krakow and attended FeNO testing. The effect of transplacental PAH exposure was adjusted for potential confounders, such as maternal allergy and children's specific atopy to common domestic allergens.

Results

FeNO values were significantly elevated in children with higher prenatal PAH exposure (gmean = 7.7 ppb; 95% CI: 5.8–10.2 ppb) compared with those at low exposure level (gmean = 3.8 ppb; 95% CI: 2.3–6.3) (P = 0.011). Children with maternal allergy had also significantly higher mean FeNO values (gmean = 13.7 ppb, 95% CI: 8.8–21.4 ppb) compared with the subjects whose mothers denied allergy (gmean = 5.6 ppb, 95% CI: 4.3–7.3 ppb) (P = 0.012). Similarly, FeNO values in atopic children were higher (gmean = 11.2 ppb; 95% CI: 3.8–32.8 ppb) than in non‐atopic individuals (gmean = 6.0 ppb; 95% CI: 4.7–7.7 ppb, P = 0.079). The results of the nested multivariable linear regression analysis showed that both maternal allergy and sensitization of children to domestic aeroallergens jointly explained 10.4% of FeNO variance, however, the additional 10.9% was determined by prenatal PAH exposure.

Conclusion

FeNO is more than a marker useful for screening atopy or symptomatic bronchial inflammation and may also be a proxy for cytokine deregulation and “allergic response” phenotype possibly established in fetal period due to transplacental PAH exposure. Preliminary results of our study should encourage more studies on intrauterine PAH exposure and later respiratory symptoms. Pediatr Pulmonol. 2012. 47:1131–1139. © 2012 Wiley Periodicals, Inc.
Efficacy of methylprednisolone in children with severe community acquired pneumonia
Authors: Nagy Bela , Gaspar Imre , Papp Agnes , Bene Zsolt , Nagy Bela , Voko Zoltan , Balla Gyorgy
Published: May 2012

Background

The clinical value of adjuvant corticosteroid treatment in community‐acquired pneumonia (CAP) seemed to be controversial in adults, and even less data are available on the use of corticosteroids in children with CAP.

Materials and Methods

In this study, we investigated the efficacy of a 5‐day adjuvant methylprednisolone therapy to imipenem in 29 children with severe CAP. In parallel, 30 subjects with the same disease were treated with imipenem and placebo, and the two study groups were compared based on the different parameters of the primary and secondary end points. The primary end points were the duration of fever, the levels of white blood cells (WBC) and high sensitive C‐reactive protein (hsCRP). Secondary end points were the length of hospital stay, and the number of severe complications with or without surgical interventions.

Results

The additive methylprednisolone treatment significantly reduced the duration of fever with 2.5 days, the WBC counts (P = 0.014), the hsCRP levels showing a 48.7% decrease, and the length of hospital stay with 5.2 days versus the placebo group. Moreover, patients treated on imipenem alone had twice more complications and four times more invasive interventions compared to those on the combined therapy.

Conclusions

The 5‐day methylprednisolone therapy with imipenem was found effective in children having severe CAP. However, trials with larger cohorts are needed to study further beneficial effects of corticosteroids in children with CAP. Pediatr Pulmonol. 2013; 48:168–175. © 2012 Wiley Periodicals, Inc.
An optimal design for patient‐specific templates for pedicle spine screws placement
Authors: Ferrari V. , Parchi P. , Condino S. , Carbone M. , Baluganti A. , Ferrari M. , Mosca F. , Lisanti M.
Published: May 2012

Background

Currently, pedicle screws are positioned using a free‐hand technique or under fluoroscopic guidance, with error in the range 10–40%, depending on the skill of the surgeon.

Methods

After spine CT acquisition, each vertebra is segmented and the surgeon plans screw positioning in a virtual environment, then the template is designed around the chosen trajectories. This design is based on surgical and mechanical considerations to obtain an optimal solution to guarantee template stability, simple positioning and minimized intervention invasiveness. In vitro evaluation on synthetic spine models and ex vivo animal tests on porcine specimens were performed, with the insertion of 28 Kirschner wires.

Results

During the in vitro tests, all the surgeons rendered positive evaluations regarding the device and considered template placement to be easy. Ex vivo tests were evaluated by CT examination, which showed that 96.5% of the Kirschner wires had been correctly inserted.

Conclusions

The proposed solution is a promising, simple, highly precise, low‐cost solution to safely performing posterior stabilization. Such a solution would be of interest even in hospitals in which a few spine interventions are performed per year, and for which it is not reasonable to purchase the equipment required for robotic or navigated approaches. Copyright © 2012 John Wiley & Sons, Ltd.
Model Predictive Control approach for guidance of spacecraft rendezvous and proximity maneuvering
Authors: Di Cairano S. , Park H. , Kolmanovsky I.
Published: May 2012

Traditionally, rendezvous and proximity maneuvers have been performed using open‐loop maneuver planning techniques and ad hoc error corrections. In this paper, a Model Predictive Control (MPC) approach is applied to spacecraft rendezvous and proximity maneuvering problems in the orbital plane. We demonstrate that various constraints arising in these maneuvers can be effectively handled with the MPC approach. These include constraints on thrust magnitude, constraints on spacecraft positioning within Line‐of‐Sight cone while approaching the docking port on a target platform, and constraints on approach velocity to match the velocity of the docking port. The two cases of a nonrotating and a rotating (tumbling) platform are treated separately, and trajectories are evaluated in terms of maneuver time and fuel consumption. For the case when the platform is not rotating and the docking port position is fixed with respect to the chosen frame, an explicit offline solution of the MPC optimization problem is shown to be possible; this explicit solution has a form of a piecewise affine control law suitable for online implementation without an on‐board optimizer. In the case of a fast rotating platform, it is, however, shown that the prediction of the platform rotation is necessary to successfully accomplish the maneuvers and to reduce fuel consumption. Finally, the proposed approach is applied to debris avoidance maneuvers with the debris in the spacecraft rendezvous path. The significance of this paper is in demonstrating that Model Predictive Control can be an effective feedback control approach to satisfy various maneuver requirements, reduce fuel consumption, and provide robustness to disturbances. Copyright © 2012 John Wiley & Sons, Ltd.