bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring of the interconversion of gamma‐butyrolactone (GBL) to gamma hydroxybutyric acid (GHB) by Raman spectroscopy
Authors: Munshi Tasnim , Brewster Victoria. L. , Edwards Howell G. M. , Hargreaves Michael D. , Jilani Shelina. K. , Scowen Ian J
Published: December 2012

Gamma‐hydroxybutyric acid (GHB) is a drug‐of‐abuse that has recently become associated with drug‐facilitated sexual assault, known as date rape. For this reason the drug is commonly found ‘spiked’ in alcoholic beverages. When GHB is in solution it may undergo conversion into the corresponding lactone, Gamma‐butyrolactone (GBL). Studies have been carried out to determine the detection limits of GHB and GBL in various solutions by Raman spectroscopy and to monitor the interconversion of GHB and GBL in solution with different pH conditions and temperature.

In this study, a portable Raman spectrometer was used to study the interconversion of GHB and GBL in water and ethanol solutions as a function of pH, time, and temperature. The aim of this was to determine the optimum pH range for conversion in order to relate this to the pH ranges that the drug is likely to be subjected to, first in spiked beverages and secondly after ingestion in the digestive system. The aim was also to identify a timescale for this conversion in relation to possible scenarios, for example if GHB takes a number of hours to convert to GBL, it is likely for the beverage to be ingested before esterification can take place. GHB and GBL were then spiked into a selection of beverages of known pH in order to study the stability of GHB and GBL in real systems. Copyright © 2012 John Wiley & Sons, Ltd.
Evolution of population genetic structure of the British roe deer by natural and anthropogenic processes (Capreolus capreolus)
Authors: Baker Karis H. , Rus Hoelzel A.
Published: December 2012

Human influence typically impacts on natural populations of conservation interest. These interactions are varied and sometimes complex, and may be negative and unintended or associated with conservation and management strategy. Understanding the details of how these interactions influence and are influenced by natural evolutionary processes is essential to the development of effective conservation strategies. In this study, we investigate a species in Britain that has experienced both negative impact through overhunting in historical times and management efforts through culls and translocations. At the same time, there are regional populations that have been less affected by human influence. We use mtDNA and nuclear microsatellite DNA markers to investigate patterns of connectivity and diversity and find multiple insular populations in Britain that probably evolved within the Holocene (when the habitat was free of ice). We identify three concurrent processes. First, surviving indigenous populations show highly provincial patterns of philopatry, maintaining and generating population structure on a small geographic scale. Second, founder populations into habitat extirpated of native populations have expanded, but remained largely insular. Third, introductions into established populations generate some admixture. We discuss the implications for the evolution of diversity of the integration of natural processes with anthropogenic influences on population size and distribution.
Biological invasions: a field synopsis, systematic review, and database of the literature
Authors: Lowry Edward , Rollinson Emily J. , Laybourn Adam J. , Scott Tracy E. , Aiello‐Lammens Matthew E. , Gray Sarah M. , Mickley James , Gurevitch Jessica
Published: December 2012

Species introductions of anthropogenic origins are a major aspect of rapid ecological change globally. Research on biological invasions has generated a large literature on many different aspects of this phenomenon. Here, we describe and categorize some aspects of this literature, to better understand what has been studied and what we know, mapping well‐studied areas and important gaps. To do so, we employ the techniques of systematic reviewing widely adopted in other scientific disciplines, to further the use of approaches in reviewing the literature that are as scientific, repeatable, and transparent as those employed in a primary study. We identified 2398 relevant studies in a field synopsis of the biological invasions literature. A majority of these studies (58%) were concerned with hypotheses for causes of biological invasions, while studies on impacts of invasions were the next most common (32% of the publications). We examined 1537 papers in greater detail in a systematic review. Superior competitive abilities of invaders, environmental disturbance, and invaded community species richness were the most common hypotheses examined. Most studies examined only a single hypothesis. Almost half of the papers were field observational studies. Studies of terrestrial invasions dominate the literature, with most of these concerning plant invasions. The focus of the literature overall is uneven, with important gaps in areas of theoretical and practical importance.
Benzannulated Cycloheptanones from Binaphthyl Platforms
Authors: Pieters Grégory , Sbargoud Kamal , Bridoux Alexandre , Gaucher Anne , Marque Sylvain , Bourdreux Flavien , Marrot Jérôme , Flot David , Wantz Guillaume , Dautel Olivier , Prim Damien
Published: December 2012

Preparations of benzannulated cycloheptanones starting from unique binaphthyl molecular platforms are described. Binaphthyl acetic acids proved suitable percursors for fused cycloheptanone architectures. Seven‐membered rings embedded in binaphthyl units were selectively generated by use of Eaton's reagent. Isomeric helical architectures arising from electrophilic cyclisation processes at second reaction sites in the precursors could also be obtained under different acidic conditions. Unambiguous discrimination between isomeric geometries was provided by multiple quantum NMR sequences. DFT calculations were performed and gave evidence of different behaviour of the substrates towards intramolecular electrophilic substitution. The theoretical approach confirmed the experimental results, agreeing completely with X‐ray data.
On the similarity of commercial EPC Gen2 pseudorandom number generators
Authors: Melià‐Seguí Joan , Garcia‐Alfaro Joaquin , Herrera‐Joancomartí Jordi
Published: December 2012

Pseudorandom generators are the main security tool in EPC Gen2 systems. Besides its statistical compliance with the standard, no further information is provided on its design, performance or generation scheme. We empirically analysed EPC Gen2 pseudorandom sequences using a novel experimental setup. From our analysis, we obtained evidences that pseudorandom number generators used in different commercial integrated circuits use the same algorithm. This paper presents the results of this analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Mobility agent based on activity rate of user and adaptive paging for location management in wireless networks
Authors: Nath Prem , Kumar Chiranjeev
Published: December 2012

In urban cities, many MUs (mobile users) follow a fixed mobility pattern. Most of the time, these users can be found in a particular registration area (RA) at a certain time period. We say that MUs follow a fixed set of RAs on a daily basis. Therefore, an MU can be located at one of the RA from the set of fixed RAs when a call arrives. In prior schemes, the location update cost is minimized by increasing paging cost. In this paper, we propose a mobility agent (MA) and adaptive paging strategy based on MUs' movement. The MA is a special functional entity in the network, and many RAs are connected to MA as per mobility pattern of an MU. The paging area is selected based on the average speed of MUs. The major features of the proposed scheme are the overall reduced location management cost and less paging time compared with existing scheme. We present analytical modeling and performance evaluation that show that the proposed scheme has less location management cost and less paging time to locate an MU compared with existing scheme. Copyright © 2012 John Wiley & Sons, Ltd.
EXTENSIONS OF HURDLE MODELS FOR OVERDISPERSED COUNT DATA
Authors: Farbmacher Helmut
Published: December 2012

Hurdle models are frequently used to model count data. Recent developments in the count data literature make it possible to relax commonly imposed assumptions of these models. On the basis of these findings, two extensions of hurdle models that make popular specifications more flexible are developed. Both extensions nest the models that have been used so far, so they can be tested by appropriate parametric restrictions. An example from health economics illustrates the relevance of both model extensions. Copyright © 2012 John Wiley & Sons, Ltd.
Qualitative estimation of SBR biological nutrient removal performance for wastewater treatment
Authors: Colomer Joan , Wong Alberto , Coma Marta , Puig Sebastià , Colprim Jesus
Published: December 2012

Background

The main goal of wastewater treatment is to obtain high quality effluent. This study proposes a methodology to estimate in real‐time the effluent quality in a biological nutrient removal (BNR) sequencing batch reactor (SBR) process.

Results

This is achieved by: (i) detecting the batch quality; and (ii) predicting the classification of the release according to different effluent characteristics. A principal component analysis (PCA) model is built to discern normal or abnormal behavior of the batch release. An index is given to every phase of the process by means of contribution analysis, and a fault signature (FS) is created. The FS in a classification model is associated with a biological removal quality.

Conclusion

The model is applied as a soft‐sensor in real‐time to new batch releases to obtain a qualitative estimate of the effluent. A correct estimation for the qualitative variables, of above 95%, would provide a reliable tool to estimate BNR performances.© 2012 Society of Chemical Industry
Profiling and sequencing of gangliosides from human caudate nucleus by chip‐nanoelectrospray mass spectrometry
Authors: Serb Alina F. , Sisu Eugen , Vukelić Željka , Zamfir Alina D.
Published: December 2012

Gangliosides (GGs), sialic acid‐containing glycosphingolipids are involved in many brain functions at the cell and molecular level. Compositional and structural elucidation of GGs in mixtures extracted from human brain is essential for correlating their profile with the specialized function of each brain area in health and disease. As a part of our ongoing study on GG expression and structure in different healthy and diseased brain regions, in this work, a preliminary investigation of GGs in a specimen of human caudate nucleus (CN) was carried out using an advanced mass spectrometry (MS) technique. By chip‐nanoelectrospray MS performed on a NanoMate robot coupled to a high capacity ion trap instrument, 81 GG components were detected in human CN in only 1.5 min of signal acquisition. Although the native GG mixture from CN was found dominated by mono‐, di‐ and trisialylated GGs with a slight dominance of disialylated forms (GD), four tetrasialylated structures (GQ) and two pentasialylated (GP) species were also identified. Additionally, species with unusually long fatty acid chains, exceeding 30 carbon atoms in their ceramide (Cer) composition, and several glycoforms modified by fucosyl (Fuc),O‐acetyl (O‐Ac) and/or lactonization were discovered. By tandem MS (MS2) using collision‐induced dissociation, two atypical mono and disialylated species with long‐chain fatty acids in their Cer could be confirmed and structurally characterized. These results may be a starting point for new GG‐based approaches in the study of CN functions and ethiopathogenesis of CN‐related neurodegenerative disorders. Copyright © 2012 John Wiley & Sons, Ltd.
Variability of phenolic content and antioxidant activity of two lettuce varieties under Fe deficiency
Authors: Msilini Najoua , Oueslati Samia , Amdouni Thouraya , Chebbi Mohamed , Ksouri Riadh , Lachaâl Mokhtar , Ouerghi Zeineb
Published: December 2012

BACKGROUND

Fe deficiency affects food growth and quality in calcareous soils. In this study, the effect of Fe deficiency on growth parameters, phenolic content and antioxidant capacities of two lettuce shoots varieties (Romaine and Vista) were investigated.

RESULTS

Fresh matter production, pigment (chlorophyll and carotenoid) and Fe2+ content were significantly reduced by Fe deficiency in both varieties. However, restriction of these parameters was particularly pronounced in Romaine variety as compared to Vista. Moreover, Fe deficiency caused decreases in the activity of antioxidant enzymes such as catalase and guaiacol peroxidase, whereas ascorbate peroxidase and malondialdehyde concentrations were not significantly affected. On the other hand, Fe deficiency in Vista variety induced an increase in polyphenol and flavonoid content as compared to Romaine variety. In addition, total antioxidant capacity and antiradical test against DPPH radical decreased in leaves of Romaine variety after 15 days of treatment.

CONCLUSION

These results suggest that the higher polyphenol content in Vista variety supports the involvement of these components in the stability of antioxidant capacities and then in its protection against oxidative damage generated by Fe deficiency in lettuce plants. © 2012 Society of Chemical Industry
Towards high‐siderophore‐content foods: optimisation of coprogen production in submerged cultures of Penicillium nalgiovense
Authors: Emri Tamás , Tóth Viktória , Nagy Csilla Terézia , Nagy Gábor , Pócsi Imre , Gyémánt Gyöngyi , Antal Károly , Balla József , Balla György , Román Gyula , Kovács István , Pócsi István
Published: December 2012

Background

Fungal siderophores are likely to possess atheroprotective effects in humans, and therefore studies are needed to develop siderophore‐rich food additives or functional foods to increase the siderophore uptake in people prone to cardiovascular diseases. In this study the siderophore contents of mould‐ripened cheeses and meat products were analysed and the coprogen production by Penicillium nalgiovense was characterised.

Results

High concentrations of hexadentate fungal siderophores were detected in penicillia‐ripened Camembert‐ and Roquefort‐type cheeses and also in some sausages. In one sausage fermented by P. nalgiovense, the siderophore content was comparable to those found in cheeses. Penicillium nalgiovense produced high concentrations of coprogen in submerged cultures, which were affected predominantly by the available carbon and nitrogen sources under iron starvation. Considerable coprogen yields were still detectable in the presence of iron when the fermentation medium was supplemented with the iron chelator Na2‐EDTA or when P. nalgiovense was co‐cultivated with Saccharomyces cerevisiae.

Conclusion

These data may be exploitable in the future development of high‐siderophore‐content foods and/or food additives. Nevertheless, the use of P. nalgiovense fermentation broths for these purposes may be limited by the instability of coprogen in fermentation media and by the β‐lactam production by the fungus. © 2012 Society of Chemical Industry
Longitudinal Correlates of Aggressive Behavior in Help‐Seeking U.S. Veterans With PTSD
Authors: Shin Hana J. , Rosen Craig S. , Greenbaum Mark A. , Jain Shaili
Published: December 2012

The current study examined the longitudinal effects of clinical and treatment utilization factors on aggressive behavior among 376 help‐seeking U.S. veterans recently diagnosed with posttraumatic stress disorder (PTSD) who were followed for 5–12 months. Participants were sampled from 4 strata: male Iraq/Afghanistan veterans, female Iraq/Afghanistan veterans, male prior‐era veterans, and female prior‐era veterans. Hierarchical regression analyses indicated that changes in PTSD severity were significantly associated with changes in aggressive behavior among veterans who reported any aggression at baseline (β = .15). Changes in days of alcohol intoxication also were positively associated with changes in aggressive behavior (β = .16). Participants with both a benzodiazepine prescription and any baseline aggression were significantly more likely to increase in aggressive behavior over time (β = .14). Contrary to our hypotheses, reductions in aggressive behavior were not related to the number of outpatient mental health visits or to first‐line recommended psychotropic medications. Results inform assessment and clinical research on changes in aggressive behavior among veterans with PTSD.
Thulium‐YAG laser sialendoscopy for parotid and submandibular sialolithiasis
Authors: Durbec M. , Dinkel E. , Vigier S. , Disant F. , Marchal F. , Faure F.
Published: December 2012

Objective

To evaluate the efficacy and safety of thulium‐YAG laser in sialendoscopic fragmentation of salivary lithiasis.

Design

Retrospective, interventional case series.

Material

Sixty‐three patients treated by interventional sialendoscopy with thulium‐Yag laser fragmentation between 2003 and 2010 at Edouard Herriot Hospital were included in the study. The laser was used for non‐floating or large lithiasis (>4 mm).

Methods

The sialendoscopic thulium fiber laser was used in a pulsed mode with an average power output of 2–8 W to fragment and facilitate extraction of salivary stones. Several variables were studied: success rate, total number of procedures, total energy per procedure, size and number of salivary stones removed, and complications.

Results

Our series of 63 cases includes 40 cases of parotid lithiasis and 23 cases of submandibular lithiasis. In nine cases, two sessions of laser were performed. Stone size was evaluated pre‐operatively by ultrasound and varied between 2 and 18 mm. Laser fragmentation was possible in every case. Complete extraction of the lithiasis was possible in 51 cases (73.9%) and partial extraction in eight cases (12.6%). Extraction failed in four cases (6.3%). Mean stone size was 5.4 mm (5.7 mm for parotid glands and 5.0 mm for sub‐mandibular glands) and mean energy per procedure was 1,450 J (range: 1,400–1,800 J). Ductal perforations were observed in 12.7% of the cases. 65.1% of patients were free of symptoms with a mean follow‐up of 18 months.

Conclusion

Thulium‐YAG laser appears to be an effective and safe technique in the treatment of salivary lithiasis. Lasers Surg. Med. 44: 783–786, 2012. © 2012 Wiley Periodicals, Inc.
Energy deposition profile in human skin upon irradiation with a 1,342 nm Nd:YAP laser
Authors: Milanič Matija , Majaron Boris
Published: December 2012

Background and Objectives

Nd:YAP laser emitting at 1,342 nm appears promising for nonablative skin rejuvenation treatment, based on favorable absorption properties of water and melanin in this part of the spectrum. A quantitative determination of energy deposition characteristics of Nd:YAP in normal human skin should enable design of a safe and effective treatment protocol for future human studies.

Study Design

Energy deposition profile of a prototype Nd:YAP laser was determined using pulsed photothermal radiometry. This technique involves time‐resolved measurement of mid‐infrared emission from a sample after pulsed laser irradiation. The laser‐induced temperature depth profile is reconstructed from the radiometric transients using a custom optimization algorithm, developed and tested earlier in our group. Measurements were performed on the extremities of four healthy volunteers at low radiant exposure (2.8 J/cm2). For the purpose of comparison, energy deposition characteristics of commercial Nd:YAG and KTP lasers (at 1,064 and 532 nm, respectively), were also determined at the same test sites.

Results

On average, the Nd:YAP laser deposits 50% of the absorbed energy within the top 0.36 mm of skin and 90% within 0.86 mm, which is significantly shallower than the Nd:YAG laser. The ratio between the dermal versus epidermal heating is more favorable and shows a smaller inter‐ and intra‐patient variance as compared to both Nd:YAG and KTP laser.

Conclusions

Energy deposition characteristics of the 1,342 nm Nd:YAP laser are very suitable for controlled heating of the upper dermis, as required for nonablative skin rejuvenation. The risks of overheating the epidermis or subcutis should be significantly reduced in comparison with the 1,064 nm Nd:YAG laser. Lasers Surg. Med. 45: 8–14, 2013. © 2012 Wiley Periodicals, Inc.
Temperature and pH Dual‐Responsive Behavior of Dendritic Poly(N‐isopropylacrylamide) with a Polyoligomeric Silsesquioxane Core and Poly(2‐hydroxyethyl methacrylate) Shell
Authors: Bai Yu , Yang Liping , Toh Cher Ling , He Chaobin , Lu Xuehong
Published: December 2012

Novel temperature and pH dual‐responsive dendritic polyoligomeric silsesquioxane (POSS)–poly(N‐isopropylacrylamide) (PNIPAm)–poly(2‐hydroxyethyl methacrylate) (PHEMA) copolymers are prepared via atom transfer radical polymerization and click reactions. The cloud points (Tc) decrease with decreasing pH from 10.0 to 5.0 due to the weakened inter‐molecular interactions and enhanced intra‐molecular hydrogen bonding, whereas the Tc exhibits a small increase from pH 5.0 to 4.0 because of the better solvation of PHEMA at highly acidic conditions. The above findings are corroborated by the different sizes of aggregates observed by dynamic light scattering. The encapsulation of a fluorescent dye and stimulated release by temperature and pH changes are also demonstrated.
Polymorphism in Sheared Isotactic Polypropylene Containing Nucleant Particles
Authors: Phillips Andrew William , Bhatia Amita , Zhu Peng‐wei , Edward Graham
Published: December 2012

This study explored the combined influence of shear flow and nucleating agents on isotactic polypropylene (iPP) crystallisation. The study showed that oriented α‐iPP crystals were not necessary to form β‐iPP crystals, contrary to the accepted view that the surface of oriented α‐iPP crystals provides nucleation sites for an α‐iPP to β‐iPP growth transition. Instead it was proposed that flow‐induced mesomorphic point‐like nuclei preferentially nucleates β‐iPP. The combined effect of shear flow and nucleant was found to promote γ‐iPP crystals. The surprising γ‐iPP nucleation effect was explained by the high density of flow‐induced and heterogeneous nuclei present at the start of crystallisation.

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Light‐Emitting Electrospun Nanofibers for Nanophotonics and Optoelectronics
Authors: Camposeo Andrea , Persano Luana , Pisignano Dario
Published: December 2012

The processing, properties, and applications of electrospun light‐emitting nanofibers are reviewed. The different experimental approaches for electrospinning conjugated polymers and light‐emitting compounds are presented. The characterization of the optoelectronic properties of electrospun conjugated polymer nanofibers evidences intriguing features, such as polarized emission, self‐waveguiding, enhanced energy transfer, and charge transport. The applications of such nanostructured materials include polarized light sources for lab‐on‐chip devices, nanoscale organic light‐emitting diodes and optically pumped lasers, field‐effect transistors, and high‐performance optical sensors. Future challenges and perspectives of electrospun light‐emitting nanofibers are also discussed.

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Non‐monotonicity of Observed Hypervolume in 1‐Greedy S‐Metric Selection
Authors: Judt Leonard , Mersmann Olaf , Naujoks Boris
Published: December 2012

The progression of the dominated hypervolume in the course of the optimization process, with respect to a global reference point, is thought to be monotonically increasing. This intuition is based on the observation that in each iteration, the solution that contributes the least to the dominated hypervolume is eliminated. Derived from results of multiple optimization runs with incorporated reference point adaptation, we show that this does not always hold for two‐dimensional and three‐dimensional objective spaces. For the two‐dimensional case, this is because the two boundary solutions are always retained in the population regardless of their hypervolume contribution. For the three‐dimensional case, we are able to show that the cause of the drop in dominated hypervolume is the continuous adaption of the reference point during selection. Copyright © 2012 John Wiley & Sons, Ltd.
A family of fundamental solutions of elliptic partial differential operators with quaternion constant coefficients
Authors: Dalla Riva M. , Morais J. , Musolino P.
Published: December 2012

The purpose of this paper is to construct a family of fundamental solutions for elliptic partial differential operators with quaternion constant coefficients. The elements of such family are expressed by means of functions, which depend jointly real analytically on the coefficients of the operators and on the spatial variable. We show some regularity properties in the frame of Schauder spaces for the corresponding single layer potentials. Ultimately, we exploit our construction by showing a real analyticity result for perturbations of the layer potentials corresponding to complex elliptic partial differential operators of order two. Copyright © 2012 John Wiley & Sons, Ltd.
Constrained source space imaging: Application to fast, region‐based functional MRI
Authors: Chiew Mark , Graham Simon J.
Published: December 2012

A new technique called constrained source space imaging is introduced that holds promise for ultrafast acquisition of functional magnetic resonance imaging data. A sparse set of arbitrarily positioned, coarse voxels is first localized using radiofrequency selective excitation, from which magnetization signals are separated using only the spatial sensitivities of multichannel receiver coils, without the need for k‐space encoding using imaging gradients. This method permits very fast acquisitions of targeted magnetization without complex or time‐consuming image reconstruction techniques. Furthermore, because the data acquisition is performed without imaging gradients, T2* decays can be densely sampled and processed for contrast enhancement to improve functional magnetic resonance imaging data quality. Here, the constrained source space imaging technique is validated in proof‐of‐concept form, for a simple functional magnetic resonance imaging motor task using a prototype dual‐band stimulated echo acquisition mode excitation to image four voxels at TR = 250 ms. Results demonstrate good voxel signal separation and good characterization of hemodynamic responses in primary motor cortices (M1) and supplementary motor areas through T2* fitting of the measured signals. With further refinement, the constrained source space imaging method has potential utility in a priori ROI‐based functional magnetic resonance imaging experiments with TR values under 100 ms. Rapid, multivoxel measurements of other sources of MR signal contrast are also possible. Magn Reson Med, 70:1058–1069, 2013. © 2012 Wiley Periodicals, Inc.
Automatic merging of tetrahedral meshes
Authors: Lo S.H.
Published: December 2012

A generic algorithm is proposed to merge arbitrary solid tetrahedral meshes automatically into one single valid finite element mesh. The intersection segments in the form of distinct nonoverlapping loops between the boundary surfaces of the given solid objects are determined by the robust neighbor tracing technique. Each intersected triangle on the boundary surface will be triangulated to incorporate the intersection segments onto the boundary surface of the objects. The tetrahedra on the boundary surface associated with the intersected triangular facets are each divided into as many tetrahedra as the number of subtriangles on the triangulated facet. There is a natural partition of the boundary surfaces of the solid objects by the intersection loops into a number of zones. Volumes of intersection can now be identified by collected bounding surfaces from the surface patches of the partition. Whereas mesh compatibility has already been established on the boundary of the solid objects, mesh compatibility has yet to be restored on the bounding surfaces of the regions of intersection. Tetrahedra intersected by the cut surfaces are removed, and new tetrahedra can be generated to fill the volumes bounded by the cut surfaces and the portion of cavity boundary connected to the cut surfaces to restore mesh compatibility at the cut surfaces. Upon restoring compatibility on the bounding surfaces of the regions of intersection, the objects are ready to be merged together as all regions of intersection can be detached freely from the objects. All operations, besides the determination of intersections structurally in the form of loops, are virtually topological, and no parameter and tolerance is needed in the entire merging process. Examples are presented to show the steps and the details of the mesh merging procedure. Copyright © 2012 John Wiley & Sons, Ltd.
Influence of core–shell particles structure on the morphology and brittle‐ductile transition of PBT/ABS‐g‐GMA blends
Authors: Fu Yan , Song Haihe , Zhou Chao , Sun Shulin , Zhang Huixuan
Published: December 2012

The performance of glycidyl methacrylate (GMA) functionalized acrylonitrile‐butadiene‐styrene core–shell impact modifiers (R‐ABS) with varied GMA content, crosslinking degree of rubber phase, core–shell ratio, and initiator type in toughening of poly(butylene terephthalate) (PBT) was investigated. Results show that 1 wt% GMA is sufficient to induce a pronounced improvement of the impact strength of PBT and too much GMA induces the crosslinking of R‐ABS. Divinylbenzene improves the crosslinking degree of polybutadiene and decreases its cavitation ability. The brittle‐ductile transition shifts to higher R‐ABS content. When the core–shell ratio of R‐ABS is beyond 70/30, compatibilization reaction is not sufficient to retard the agglomeration of core–shell particles. R‐ABS particles with the core–shell ratio between 50/50 and 60/40 are suitable. Initiator type can influence the internal structure of R‐ABS. For R‐ABS prepared with azobisisobutyronitrile (AIBN) as initiator, big subinclusion structure decreases its toughening ability. R‐ABS prepared with redox initiator shows better toughening behavior. POLYM. COMPOS., 2013. © 2012 Society of Plastics Engineers
Photovoltaic module calibration value versus optical air mass: the air mass function
Authors: Osterwald C.R. , Emery K.A. , Muller M.
Published: December 2012

So‐called “air mass functions” of photovoltaic modules are used to approximate the effects of spectral responsivity and to correct short‐circuit current to or from a reference condition. These empirical functions are determined from outdoor measurements with test modules mounted on two‐axis solar trackers and then calculated from plots of normalized calibration value (short‐circuit current divided by total irradiance) versus optical air mass. Because they are incorporated into a number of photovoltaic system modeling and sizing software programs, the accuracy of the functions has direct implications for system costs. We discuss the assumptions associated with these functions that are generally not considered or ignored, and study their variability with respect to atmospheric constituents. The variability study included a 6‐month outdoor measurement on a crystalline‐Si module and a software simulation of the same module using a solar spectral irradiance model. We conclude that air mass functions depend on the measurement location and time, and therefore are not unique to a particular device. Also, using these functions introduces two distinct errors, the magnitudes of which are unknown without knowledge of spectral irradiance conditions. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Improvement of the cell performance in the ZnS/Cu(In,Ga)Se2 solar cells by the sputter deposition of a bilayer ZnO : Al film
Authors: Shin Dong Hyeop , Kim Ji Hye , Shin Young Min , Yoon Kyung Hoon , Al‐Ammar Essam A. , Ahn Byung Tae
Published: December 2012

ZnS is a candidate to replace CdS as the buffer layer in Cu(In,Ga)Se2 (CIGS) solar cells for Cd‐free commercial product. However, the resistance of ZnS is too large, and the photoconductivity is too small. Therefore, the thickness of the ZnS should be as thin as possible. However, a CIGS solar cell with a very thin ZnS buffer layer is vulnerable to the sputtering power of the ZnO : Al window layer deposition because of plasma damage. To improve the efficiency of CIGS solar cells with a chemical‐bath‐deposited ZnS buffer layer, the effect of the plasma damage by the sputter deposition of the ZnO : Al window layer should be understood. We have found that the efficiency of a CIGS solar cell consistently decreases with an increase in the sputtering power for the ZnO : Al window layer deposition onto the ZnS buffer layer because of plasma damage. To protect the ZnS/CIGS interface, a bilayer ZnO : Al film was developed. It consists of a 50‐nm‐thick ZnO : Al plasma protection layer deposited at a sputtering power of 50 W and a 100‐nm‐thick ZnO : Al conducting layer deposited at a sputtering power of 200 W. The introduction of a 50‐nm‐thick ZnO : Al layer deposited at 50 W prevented plasma damage by sputtering, resulting in a high open‐circuit voltage, a large fill factor, and shunt resistance. The ZnS/CIGS solar cell with the bilayer ZnO : Al film yielded a cell efficiency of 14.68%. Therefore, the application of bilayer ZnO : Al film to the window layer is suitable for CIGS solar cells with a ZnS buffer layer. Copyright © 2012 John Wiley & Sons, Ltd.
Development and clinical application of an enzyme immunoassay for the determination of midregional proadrenomedullin
Authors: Suzuki Yosuke , Itoh Hiroki , Katagiri Fumihiko , Sato Fuminori , Sato Yukie , Kawasaki Kanako , Sato Yuhki , Mimata Hiromitsu , Takeyama Masaharu
Published: December 2012

Adrenomedullin (ADM) is a 52‐amino acid peptide with a variety of physiologic functions such as immunomodulating activity, direct bactericidal activity, maintenance of renal homeostasis, and vasodilatory activity. Midregional proADM (MR‐proADM) is derived from a larger 185‐amino acid precursor peptide, prepro‐adrenomedulin (preproADM), by posttranslational processing. It is suggested to be co‐synthesized with ADM in equimolar amounts and has the advantages over ADM in having a longer half‐life, no bioactivity, and no binding to protein. Therefore, MR‐proADM serves as a surrogate for ADM secretion. In this study, we attempted to develop an enzyme immunoassay (EIA) for quantifying MR‐proADM‐like immunoreactive substance (IS), which is applicable for monitoring plasma MR‐proADM levels. By using β‐d‐galactosidase‐labeled preproADM(83‐94) as a marker antigen, anti‐rabbit IgG‐coated immunoplate as a bound/free separator, and 4‐methylumbelliferyl‐β‐d‐galactopyranoside as a fluorogenic substrate, a sensitive and specific EIA was developed for the quantification of MR‐proADM‐IS in human plasma. The lower limit of quantification was 0.032 pmol/well, and the steep competitive inhibition EIA calibration curve obtained was linear between 0.16 and 10 nmol/L. By using human plasma samples containing 0.2 and 2.0 nmol/L of MR‐proADM, the interassay coefficients of variation (reproducibility) were 10.78% and 8.83%, respectively, and intraassay coefficients were 3.91% and 7.81%. Plasma MR‐proADM‐IS level was significantly higher in patients with chronic renal failure (1.39 ± 0.50 nmol/L) compared with healthy subjects (0.19 ± 0.07 nmol/L). These results suggest that our EIA may be useful to evaluate plasma MR‐proADM levels as a biomarker in various clinical settings. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Lateral modulation doping of two‐dimensional electron or hole gas
Authors: Dmitriev A. , Shur M.
Published: December 2012

We show that the two‐dimensional electron gas (2DEG) injected from the region with a higher concentration into the region with a lower concentration decays very slowly. In contrast to the three‐dimensional case, where the concentration is an exponential function of distance from the injecting contact, the 2D concentration is inversely proportional to this distance. Moreover, using passivation with a high dielectric constant or a floating metal gate placed close to the 2DEG (with separation smaller than the Bohr radius) could dramatically enhance the 2DEG concentration decay length. This effect enables lateral remote electron transfer in 2DEG, similar to remote doping in heterostructures, and can be used to optimize the electric field and/or electron concentration profile.
High color rendering index and chromatic stability of top‐emitting white organic light‐emitting diodes capped with a supplementary green color conversion layer
Authors: Li Jiaheng , Zhu Wenqing , Xiong Linghao , Sun Wenbing , Wu Xiaoliang , Cao Jin
Published: December 2012

We have demonstrated high color rendering index (CRI) and chromatic stability of top‐emitting white organic light‐emitting diodes (TEWOLEDs) by capping a supplementary green color conversion layer (CCL) on the cathode of single blue emitter based TEWOLEDs. By employing CCLs, blue photon energy is absorbed and converted to green emission efficiently, resulting in an improvement of CRI from 72 to 86. We attribute the increased high CRI to the broadening of the out‐coupled spectrum and an appropriate intensity match among the three primary colors. Meanwhile, the TEWOLEDs show extremely high chromatic stability. The results indicate that this method provides a new avenue to improve the CRI of TEWOLEDs.

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(© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Localized directed orbitals representing chemical bonds in ion‐covalent crystals
Authors: Abarenkov Igor V. , Boyko Maksim A. , Sushko Peter V.
Published: December 2012

We propose a new method for decomposing electron density of a crystal into contributions associated with pair‐wise chemical bonds. To this end, an ion‐covalent crystal is represented using a neutral, closed shell cluster assembled from identical structural elements (SE) and embedded into the lattice electrostatic potential. The wave function of this cluster is calculated using the one determinant approximation. Then, a set of orthonormal, noncanonical, multicenter orbitals of the cluster valence states is generated, so as each orbital is localized on one structural element. The projection operators technique is used here, the valence molecular orbitals of the cluster being taken for the orthonormal basis set. In this construction, the first‐order reduced density matrix of the cluster valence electrons is exactly the sum of the first‐order reduced density matrices of the SE, and the latter is the exact sum of localized on this cluster orbitals densities. The localized orbitals are then transformed into directed orbitals corresponding to the ion‐covalent bonds in each structural element. The first‐order reduced density matrix of each structural element is exactly the sum of densities of all such corresponding directed orbitals. This method is demonstrated on the examples of MgO, cubic ZrO2, and rutile TiO2 crystals. © 2012 Wiley Periodicals, Inc.
Selection by rank in K‐dimensional binary search trees
Authors: Duch Amalia , Jiménez Rosa M. , Martínez Conrado
Published: December 2012

In this work we show how to augment general purpose multidimensional data structures, such as K‐d trees, to efficiently support search by rank (that is, to locate the i‐th smallest element along the j‐th coordinate, for given i and j) and to find the rank of a given item along a given coordinate. To do so, we introduce two simple, practical and very flexible algorithms – Select‐by‐Rank and Find‐Rank – with very little overhead. Both algorithms can be easily implemented and adapted to several spatial indexes, although their analysis is far from trivial. We are able to show that for random K‐d trees of size n the expected number of nodes visited by Find‐Rank is for or , and for (with ), where depends on the dimension K and the variant of K‐d tree under consideration. We also show that Select‐by‐Rank visits nodes on average, where is the given rank and the exponent α is as above. We give the explicit form of the functions and , both are bounded in [0, 1] and they depend on K, on the variant of K‐d tree under consideration, and, eventually, on the specific coordinate j for which we execute our algorithms. As a byproduct of the analysis of our algorithms, but no less important, we give the average‐case analysis of a partial match search in random K‐d trees when the query is not random. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 45, 14–37, 2014
Phase formation and impurity effects in Ar+ ion irradiated Mo/Si thin film bilayer system
Authors: Singh Ch. Kishan , Ilango S. , Dash S. , Tyagi A. K.
Published: December 2012

We report a dose‐dependent phase evolution in Mo/Si bilayer system upon Ar+ ion beam irradiation and subsequent flash annealing at 800 °C for 60 s. Micro‐structural characterization with Grazing Incidence X‐ray Diffraction and Raman scattering reveals a dose‐dependent nucleation of polymorphic phases occurring at the amorphized interface region. The ion beam mixing process has been investigated by Secondary Ion Mass Spectrometry and Rutherford Backscattering Spectrometry. While low ion doses favour nucleation of only metastable MoSi2 phase, co‐existence of polymorphic phases are observed at high ion doses. The persistence of such polymorphic phases even after a high‐temperature anneal for high dose implanted specimen is indicative of phase retardation. The phase retardation of h‐MoSi2 to t‐MoSi2 is accounted in terms of nucleation and growth process. Copyright © 2012 John Wiley & Sons, Ltd.
Formation of amino‐terminated self‐assembled monolayers from long‐chain aminomethoxylsilanes
Authors: Liu Lei , Song Shiyong , Zhang Pingyu
Published: December 2012

3‐Aminopropyltriethoxylsilane (APS), N‐[3‐(Trimethoxylsilyl)propyl]‐ethylenediamine, N‐[3‐(Trimethoxylsilyl)propyl]diethyenetriamine were assembled onto silicon surfaces. Using a mixture of acetone and water as solvent, factors which would affect the formation of amino‐terminated self‐assembled monolayers (SAMs), such as water content in solvent and reaction time, were investigated. The structural information of SAMs was collected from contact angle measurements, ellipsometric thickness measurements and X‐ray photoelectronic spectroscopy. Reaction time and water content in solvent produced dominant effects on the formation of amino terminated SAMs. The method introduced in this paper also presents a simple and controllable way to prepare amino‐terminated SAMS. Copyright © 2012 John Wiley & Sons, Ltd.
Relationship between Hair Cortisol and Perceived Chronic Stress in a Diverse Sample
Authors: O'Brien K. M. , Tronick E. Z. , Moore C. L.
Published: December 2012

Hair cortisol (CORT) is a biomarker of chronic stress via long‐term alterations in hypothalamus–pituitary–adrenal axis activity. Relationships to perceived stress measures, however, have rarely been specifically investigated. A diverse sample of 135 adults participated in a study assessing relationships between chronic stress indicator CORT to perceived stress and health indicators. CORT was not correlated to single perceived domain indices but with a global stress composite. Differences in objective and subjective measures were found for sociodemographics: racial/ethnic identity, sex and socioeconomic status (SES). Race by SES interactions predicted both CORT and perceived stress, but produced a complex and partially unanticipated pattern of results. For minorities, low and high SES showed the highest CORT, with mid‐SES showing the lowest CORT; there was little change in perceived stress at all levels of SES. For non‐minorities, mid‐SES showed the highest CORT, with decreases in both CORT and perceived stress in high SES. The unanticipated findings of deleterious outcomes for high SES minorities highlight the importance of investigating potential stressors and moderators, including perceived discrimination and social identity. Moreover, these results suggest that CORT may not always correlate with single stress indices but may provide a global assessment of chronic stress, with implications for the allostatic load literature. Copyright © 2012 John Wiley & Sons, Ltd.
Interpersonal Aggression and Burnout: The Mediating Role of Psychological Climate
Authors: Bedi Akanksha , Courcy Francois , Paquet Maxime , Harvey Steve
Published: December 2012

Using the theoretical perspectives offered by stressor–stress–strain framework and fairness theory, the authors propose that psychological climate will mediate the positive relationship between interpersonal aggression and employee burnout. Data from a survey of 1893 hospital employees suggested that psychological climate partially mediated the relationship between interpersonal aggression and two of the three dimensions of burnout, emotional exhaustion and depersonalization. The theoretical and practical implications of these findings and directions for future research are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Regulation of developmental processes: insights from mass spectrometry‐based proteomics
Authors: Veraksa Alexey
Published: December 2012

Mass spectrometry (MS)‐based proteomics has become an indispensable tool for protein identification and quantification. In this paper, common MS workflows are described, with an emphasis on applications of MS‐based proteomics in developmental biology. Progress has been made in the analysis of proteome changes during tissue differentiation and in various genetic perturbations. MS‐based proteomics has been particularly useful for identifying novel protein interactions by affinity purification‐mass spectrometry (AP‐MS), many of which have been subsequently functionally validated and led to the discovery of previously unknown modes of developmental regulation. Quantitative proteomics approaches can be used to study posttranslational modifications (PTMs) of proteins such as phosphorylation, to reveal the dynamics of intracellular signal transduction. Integrative approaches combine quantitative MS‐based proteomics with other high‐throughput methods, with the promise of a systems level understanding of developmental regulation. WIREs Dev Biol 2013, 2:723–734. doi: 10.1002/wdev.102

This article is categorized under:

Technologies > Analysis of Cell, Tissue, and Animal Phenotypes

Technologies > Analysis of Proteins
Liouville’s imaginary shadow
Authors: Schomerus Volker , Suchanek Paulina
Published: December 2012

Abstract

$ \mathcal{N}=1 $
super Liouville field theory is one of the simplest non-rational conformal field theories. It possesses various important extensions and interesting applications, e.g. to the AGT relation with 4D gauge theory or the construction of the OSP(1|2) WZW model. In both setups, the
$ \mathcal{N}=1 $
Liouville field is accompanied by an additional free fermion. Recently, Belavin et al. suggested a bosonization of the product theory in terms of two bosonic Liouville fields. While one of these Liouville fields is standard, the second turns out to be imaginary (or time-like). We extend the proposal to the R sector and perform extensive checks based on detailed comparison of 3-point functions involving several super-conformal primaries and descendants. On the basis of such strong evidence we sketch a number of interesting potential applications of this intriguing bosonization.