bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of an empirical orthogonal function–based method to downscale soil moisture patterns based on topographical attributes
Authors: Busch Frederick A. , Niemann Jeffrey D. , Coleman Michael
Published: October 2011

Soil moisture influences many hydrologic applications including agriculture, land management and flood prediction. Most remote‐sensing methods that estimate soil moisture produce coarse resolution patterns, so methods are required to downscale such patterns to the resolutions required by these applications (e.g. 10‐ to 30‐m grid cells). At such resolutions, topography is known to affect soil moisture patterns. Although methods have been proposed to downscale soil moisture based on topography, they usually require the availability of past high‐resolution soil moisture patterns from the application region. The objective of this article is to determine whether a single topographic‐based downscaling method can be used at multiple locations without relying on detailed local observations. The evaluated downscaling method is developed on the basis of empirical orthogonal function (EOF) analysis of space–time soil moisture data at a reference catchment. The most important EOFs are then estimated from topographic attributes, and the associated expansion coefficients are estimated on the basis of the spatial‐average soil moisture. To test the portability of this EOF‐based method, it is developed separately using four data sets (Tarrawarra, Tarrawarra 2, Cache la Poudre and Satellite Station), and the relationships that are derived from these data sets to estimate the EOFs and expansion coefficients are compared. In addition, each of these downscaling methods is applied not only for the catchment where it was developed but also to the other three catchments. The results suggest that the EOF downscaling method performs well for the location where it is developed, but its performance degrades when applied to other catchments. Copyright © 2011 John Wiley & Sons, Ltd.
Osteochondral interface regeneration of the rabbit knee with macroscopic gradients of bioactive signals
Authors: Dormer Nathan H. , Singh Milind , Zhao Liang , Mohan Neethu , Berkland Cory J. , Detamore Michael S.
Published: October 2011

To date, most interfacial tissue engineering approaches have used stratified designs, in which there are two or more discrete layers comprising the interface. Continuously graded interfacial designs, where there is no discrete transition from one tissue type to another, are gaining attention as an alternative to stratified designs. Given that osteochondral regeneration holds the potential to enhance cartilage regeneration by leveraging the healing capacity of the underlying bone, we endeavored to introduce a continuously‐graded approach to osteochondral regeneration. The purpose of this study was thus to evaluate the performance of a novel gradient‐based scaffolding approach to regenerate osteochondral defects in the New Zealand White rabbit femoral condyle. Bioactive plugs were constructed from poly(D,L‐lactic‐co‐glycolic acid) microspheres with a continuous gradient transition between cartilage‐promoting and bone‐promoting growth factors. At 6 and 12 weeks of healing, results suggested that the implants provided support for the neo‐synthesized tissue, and the gradient in bioactive signaling may have been beneficial for bone and cartilage regeneration compared to the blank control implant, as evidenced by histology. In addition, the effects of preseeding gradient scaffolds with umbilical cord mesenchymal stromal cells (UCMSCs) from the Wharton's jelly of New Zealand White rabbits were evaluated. Results indicated that there may be regenerative benefits to prelocalizing UCMSCs within scaffold interiors. The inclusion of bioactive factors in a gradient‐based scaffolding design is a promising new treatment strategy for defect repair in the femoral condyle. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Synthesis and characterization of injectable, thermosensitive, and biocompatible acellular bone matrix/poly(ethylene glycol)‐poly (ε‐caprolactone)‐poly(ethylene glycol) hydrogel composite
Authors: Ni Pei‐Yan , Fan Min , Qian Zhi‐Yong , Luo Jing‐Cong , Gong Chang‐Yang , Fu Shao‐Zhi , Shi Shuai , Luo Feng , Yang Zhi‐Ming
Published: October 2011

In orthopedic tissue engineering, the extensively applied acellular bone matrix (ABM) can seldom be prefabricated just right to mold the cavity of the diverse defects, might induce severe inflammation on account of the migration of small granules and usually bring the patients great pain in the treatment. In this study, a new injectable thermosensitive ABM/PECE composite with good biocompatibility was designed and prepared by adding the ABM granules into the triblock copolymer poly(ethylene eglycol)‐poly(ε‐caprolactone)‐poly(ethylene eglycol) (PEG‐PCL‐PEG, PECE). The PECE was synthesized by ring‐opening copolymerization and characterized by 1H NMR. The ABM was prepared by acellular treatment of natural bone and ground to fine granules. The obtained ABM/PECE composite showed the most important absorption bands of ABM and PECE copolymer in FT‐IR spectroscopy and underwent sol–gel phage transition from solution to nonflowing hydrogel at 37°C. SEM results indicated that the ABM/PECE composite with different ABM contents all presented similar porous 3D structure. ABM/PECE composite presented mild cytotoxicity to rat MSCs in vitro and good biocompatibility in the BALB/c mice subcutis up to 4 weeks. In conclusion, all the results confirmed that the injectable thermosensitive ABM/PECE composite was a promising candidate for orthopedic tissue engineering in a minimally‐invasive way. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Characterization of norovirus strains in Australian children from 2006 to 2008: Prevalence of recombinant strains
Authors: Mahar Jackie E. , Kirkwood Carl D.
Published: October 2011

Noroviruses are highly infectious and are the most common cause of gastroenteritis outbreaks. Genotype II.4 strains have been the dominant type identified in adults, however the genotype distribution in children is less clearly defined. This study aimed to detect and genotype norovirus strains infecting children hospitalized with acute gastroenteritis in Melbourne, Australia from 2006 to 2008. Stool samples were collected from 272 children admitted to the Royal Children's Hospital, Melbourne, Australia, with non‐rotavirus acute gastroenteritis between April 2006 and December 2008. Using RT‐PCR, norovirus was detected in 36% of samples. Strains were genetically characterized via analysis of regions from both the capsid gene and the RNA dependent RNA polymerase (RdRp) gene, to investigate genotype distribution and incidence of recombination. Typing based on the capsid gene (n = 70) detected GII.4 (49%) and GII.3 (46%) as the most predominant genotypes. Strains with a GII.4 capsid were usually assigned a GII.4 RdRp, whereas most strains identified as GII.3 based on capsid typing were assigned a GIIb RdRp (71%). The GII.3/GIIb represent recombinant strains. Sequence analysis of the putative recombination breakpoint was performed for three representative suspected recombinants: GII.3/GIIb (n = 2) and GII.3/GII.12 (n = 1). Recombination analysis confirmed these strains as recombinants and identified putative breakpoints adjacent to the ORF1/ORF2 junction. This study highlights the importance of norovirus infection as a cause of pediatric gastroenteritis. It also reinforces the high circulation of recombinant strains causing disease in children, particularly the GII.3/GIIb strain. J. Med. Virol. 83:2213–2219, 2011. © 2011 Wiley Periodicals, Inc.
High prevalence of human papillomaviruses in fresh frozen breast cancer samples
Authors: Antonsson Annika , Spurr Terrence P. , Chen Alice C. , Francis Glenn D. , McMillan Nigel A.J. , Saunders Nicholas A. , Law Michael , Bennett Ian C.
Published: October 2011

While the etiology of breast cancer remains enigmatic, some recent reports have examined the role of human papillomavirus (HPV) in breast carcinogenesis. The purpose of this study was to determine the prevalence of HPV in breast cancer tissue using PCR analysis and sequencing. Fifty‐four (54) fresh frozen breast cancers samples that were removed from a cohort of breast cancer patients were analyzed. Samples were tested for HPV using comprehensive PCR primers, and in situ hybridization was performed on paraffin embedded tissue sections. Findings were correlated with clinical and pathological characteristics. The HPV DNA prevalence in the breast cancer samples was 50% (27/54) with sequence analysis indicating all cases to be positive for HPV‐18 type. While HPV patients were slightly younger, no correlation was noted for menopausal status or family history. HPV positive tumors were smaller with earlier T staging and demonstrated lesser nodal involvement compared to HPV negative cancers. In situ hybridization analyses proved negative. The high proportion of HPV positive breast cancers detected in this series using fresh frozen tissues cannot be dismissed, however the role of HPV in breast carcinogenesis remains unclear and may ultimately be ascertained by monitoring future breast cancer incidence amongst women vaccinated against high risk HPV types. J. Med. Virol. 83:2157–2163, 2011. © 2011 Wiley Periodicals, Inc.
Intrathecal antibody production in two cases of yellow fever vaccine associated neurotropic disease in Argentina
Authors: Pires‐Marczeski Fanny Clara , Martinez Valeria Paula , Nemirovsky Corina , Padula Paula Julieta
Published: October 2011

During the period 2007–2008 several epizootics of Yellow fever with dead of monkeys occurred in southeastern Brasil, Paraguay, and northeastern Argentina. In 2008 after a Yellow fever outbreak an exhaustive prevention campaign took place in Argentina using 17D live attenuated Yellow fever vaccine. This vaccine is considered one of the safest live virus vaccines, although serious adverse reactions may occur after vaccination, and vaccine‐associated neurotropic disease are reported rarely. The aim of this study was to confirm two serious adverse events associated to Yellow fever vaccine in Argentina, and to describe the analysis performed to assess the origin of specific IgM against Yellow fever virus (YFV) in cerebrospinal fluid (CSF). Both cases coincided with the Yellow fever vaccine‐associated neurotropic disease case definition, being clinical diagnosis longitudinal myelitis (case 1) and meningoencephalitis (case 2). Specific YFV antibodies were detected in CSF and serum samples in both cases by IgM antibody‐capture ELISA. No other cause of neurological disease was identified. In order to obtain a conclusive diagnosis of central nervous system (CNS) infection the IgM antibody index (AIIgM) was calculated. High AIIgMvalues were found in both cases indicating intrathecal production of antibodies and, therefore, CNS post‐vaccinal YFV infection could be definitively associated to YFV vaccination. J. Med. Virol. 83:2208–2212, 2011. © 2011 Wiley Periodicals, Inc.
Transcriptional features and transcript structure of UL145 in different strains of human cytomegalovirus
Authors: Wang Ning , Ma Yanping , Sun Zhengrong , Qi Ying , Ji Yaohua , He Rong , Li Mali , Ruan Qiang
Published: October 2011

The human cytomegalovirus UL145 gene is located between the highly variable genes UL144 and UL146 in the UL/b′ region. However, unlike its neighboring genes, UL145 is relatively conserved among strains isolated from patients. The transcriptional features and transcript structure of UL145 has not yet been examined. In this study, the transcriptional features and structure of UL145 were characterized using RNA preparations from three HCMV strains isolated from patients, designated H, C, and X, respectively. Two transcripts were identified by cDNA library screening. Two main clusters of transcripts, one located between 500 and 700 nt, and the other between 1,400 and 1,700 nt, were confirmed by Northern blot analysis. Abundant transcripts were detected at 96 h post‐infection by Northern blot, suggesting that UL145 was a late gene. The terminal sequences of transcripts obtained by 3′ rapid amplification of cDNA ends demonstrated the presence of polyadenylation. Transcripts identified in the RNA of H, C, and X strains 96 h post‐infection had the same 3′ end but different 5′ ends. In addition to polycistronic transcripts with upstream genes, UL145 could be transcribed as a single transcript during late strain infections. J. Med. Virol. 83:2151–2156, 2011. © 2011 Wiley Periodicals, Inc.
High expression of disease‐related Cln6 in the cerebral cortex, purkinje cells, dentate gyrus, and hippocampal ca1 neurons
Authors: Thelen Melanie , Fehr Susanne , Schweizer Michaela , Braulke Thomas , Galliciotti Giovanna
Published: October 2011

Mutations in the CLN6 gene cause a variant form of late infantile neuronal ceroid lipofuscinosis, a relentless neurodegenerative disease that is inherited as an autosomal recessive trait in humans and in the naturally occurring nclf mouse strain. The CLN6 protein is localized in the endoplasmic reticulum, but it has an unknown function. To develop a molecular understanding of neurodegeneration induced by mutations in CLN6, we examined the spatial and temporal distribution of Cln6 mRNA expression in murine brain. By using Northern blot and tissue qPCR array techniques, a single Cln6 transcript was detected throughout the adult brain, with greatest expression in the cerebellum and hypothalamus. Real‐time qPCR showed 2.4–4‐fold increases in Cln6 mRNA levels in the cortex and cerebellum during the first 28 days of life, with less prominent enhancement of expression in the hippocampus. In situ hybridization analyses demonstrated Cln6 expression in brainstem, dentate gyrus, and hippocampal neurons of newborn P0 mice. From P14 onward, Cln6 expression is widely distributed throughout the brain and is most prominent in cells of cortical layers II–VI, the Purkinje cell layer, dentate gyrus, and hippocampal CA1 region of adult mice. In different regions of the brain in P0 and P28 nclf mice, the Cln6 mRNA abundance was reduced by 30–40% compared with control mice. These findings implicate Cln6 in the survival and maturation of specific neuronal populations during development and make it possible to compare regional Cln6 expression with the distribution of subsequent pathology. © 2011 Wiley Periodicals, Inc.
SERS activity and stability of the most frequently used silver colloids
Authors: Larmour I. A. , Faulds K. , Graham D.
Published: October 2011

Single‐molecule detection by surface‐enhanced resonance Raman scattering (SERRS) spectroscopy has been demonstrated for a variety of molecules. The detection of single molecules that do not have a resonance contribution, SERS, has been shown in the case of adenine. However, when colloidal particles isolated on planar substrates are used as the enhancing medium, the presence of anomalous signals significantly complicates the analysis of the spectra. Selection of a silver colloid that minimizes these spurious signals should improve the ultra‐sensitive detection of non‐resonant single molecules by SERS. A range of silver colloids, prepared by different methods, were investigated with respect to their activity and stability. Minimal anomalous signals were obtained from hydroxylamine‐reduced silver colloids, which suggests that this colloid will be better for ultra‐sensitive SE(R)RS experiments compared to the more common citrate‐ and borohydride‐reduced silver colloids. Copyright © 2011 John Wiley & Sons, Ltd.
In vitro and in vivo anti‐tumour activities of echinoside A and ds‐echinoside A from Pearsonothuria graeffei
Authors: Zhao Qin , Xue Yong , Wang Jing‐feng , Li Hui , Long Teng‐teng , Li Zhaojie , Wang Yu‐ming , Dong Ping , Xue Chang‐hu
Published: October 2011

BACKGROUND:Echinoside A (EA) and ds‐echinoside A (DSEA) are triterpene glycosides isolated from the sea cucumber Pearsonothuria graeffei. DSEA, the desulfurisation product of EA, has the following structure: β‐D‐xylopyranosyl‐holost‐8(9),11(12)‐diene‐3β,17α‐diol. In the present study, we examined the anti‐tumour activities—in particular, the structure‐activity relationships—of EA and DSEA in vitro and in vivo.

RESULTS: Both EA and DSEA exhibited an inhibitory effect on cell proliferation, along with apoptosis‐inducing activity, in HepG2 cells. Moreover, they significantly arrested the cell cycle in the G0/G1 phase. A reverse transcriptase‐polymerase chain reaction assay revealed that EA and DSEA significantly increased the expression of the cell‐cycle‐related genes, namely, p16, p21 and c‐myc, and decreased that of cyclin D1. Western blotting analysis demonstrated that they down‐regulated the expression of Bcl‐2, and enhanced mitochondrial cytochrome c release, caspase‐3 activation, and poly(adenosine diphosphate ribose) polymerase, cleavage. Nuclear factor kappa B (NF‐κB) expression was significantly decreased by DSEA, but was unaffected by EA. EA and DSEA (2.5 mg kg−1) treatment of mice bearing H22 hepatocarcinoma tumours reduced the tumour weight by 49.8% and 55.0%, respectively.

CONCLUSION: EA and DSEA exhibit marked anti‐cancer activity in HepG2 cells, by blocking cell‐cycle progression and inducing apoptosis through the mitochondrial pathway. DSEA‐induced apoptosis was more potent than EA‐induced apoptosis. Furthermore, the two triterpene glycosides derived from P. graeffei may induce apoptosis of HepG2 cells in an NF‐κB‐dependent or NF‐κB‐independent manner, depending on their structure. Copyright © 2011 Society of Chemical Industry
Oncofetal protein, IMP‐3, a potential marker for prediction of postoperative peritoneal dissemination in gastric adenocarcinoma
Authors: Okada Kaoru , Fujiwara Yoshiyuki , Nakamura Yurika , Takiguchi Shuji , Nakajima Kiyokazu , Miyata Hiroshi , Yamasaki Makoto , Kurokawa Yukinori , Takahashi Tsuyoshi , Mori Masaki , Doki Yuichiro
Published: October 2011

Background

The aim of this study was to determine the expression of insulin‐like growth factor‐II messenger RNA (mRNA)‐binding protein‐3 (IMP‐3) and its clinical significance in gastric cancers, as well the prognostic value of its expression in the peritoneal lavage fluid after surgery.

Methods

IMP‐3 expression was examined by immunohistochemistry in 96 primary gastric tumors. IMP‐3 mRNA expression in peritoneal lavage fluid obtained at laparotomy was determine by real‐time quantitative reverse transcriptase‐polymerase chain reaction (RT‐PCR).

Results

Positive staining for IMP‐3 was observed in 74% (71/96) of the tumors. IMP‐3 expression in gastric tumors correlated significantly with worst overall survival (OS) and recurrence‐free survival. Multivariate analyses identified pathological N stage and IMP‐3 expression as significant independent prognostic factors for disease‐free survival. Eight (28%) of 36 peritoneal lavage samples were cytologically negative but positive for IMP‐3 mRNA expression by RT‐PCR. The OS of patients with IMP‐3‐positive peritoneal lavage was significantly worse than of those with negative expression.

Conclusions

IMP‐3 expression in primary gastric tumors was an independent poor prognostic factor. IMP‐3 mRNA expression in peritoneal lavage fluid was a predictor of recurrence after surgery in gastric cancer and a marker of poor prognosis. J. Surg. Oncol. 2012; 105:780–785. © 2011 Wiley Periodicals, Inc.
Improvement of peak shape in aqueous normal phase analysis of anionic metabolites
Authors: Pesek Joseph J. , Matyska Maria T. , Fischer Steven M.
Published: October 2011

The problem of poor peak shape for multiply charged negative‐ion analytes under aqueous normal phase (ANP) conditions is investigated. Because less than adequate efficiency and symmetry can occur with a variety of mobile phases, gradients and additives, and to varying degrees depending on the instrument, sources other than solute/stationary phase interactions are more likely the cause. Since it is known that many of these compounds can interact strongly with metal ions, addition of a chelating agent to the mobile phase and/or the sample solvent was tested. In particular, ethylenediaminetetraacetic acid (EDTA) is a compound that forms strong complexes with most di‐and tri‐valent metal ions and can be used to verify whether trace amounts of these species are the source of the problem. In addition, the retention of a number of anionic compounds was measured at various concentrations of ammonium acetate and formate with EDTA in the mobile phase.
On boundary correspondences under quasiconformal harmonic mappings between smooth Jordan domains
Authors: Kalaj David
Published: October 2011

A quantitative version of an inequality obtained in [8, Theorem 2.1] is given. More precisely, for normalized K quasiconformal (q.c.) harmonic mappings of the unit disk onto a Jordan domain Ω ∈ C1, μ (0 < μ ≤ 1), we give an explicit Lipschitz constant depending on the structure of Ω and on K. In addition, we give a characterization of q.c. harmonic mappings of the unit disk onto an arbitrary Jordan domain with C2, α boundary in terms of the boundary function using the Hilbert transform. Moreover, a sharp explicit quasiconformal constant is given in terms of the boundary function.
Records linkage of electronic databases for the assessment of adverse effects of antiretroviral therapy in sub‐Saharan Africa
Authors: Corbell Catherine , Katjitae Ishmael , Mengistu Assegid , Kalemeera Francis , Sagwa Evans , Mabirizi David , Lates Jennie , Nwokike Jude , Fuller Sherrilyne , Stergachis Andy
Published: October 2011

Purpose

In 2009, the Ministry of Health and Social Services in Namibia decided to conduct a confirmatory assessment of the risk of anemia associated with zidovudine (AZT)‐based highly active antiretroviral therapy (HAART) using records contained in three electronic databases. These records did not share a unique identifying number. The first step was to apply probabilistic record linkage methods to link records in the three databases.

Methods

Records of persons, aged 19–65 years, newly initiated on HAART between January 2007 and June 2008, were selected from a pharmacy electronic dispensing tool (EDT) and linked to an electronic medical records database (ePMS) and a laboratory database (MEDITECH). Using the paper‐based clinical record as the gold standard, we measured the sensitivity of the starting HAART regimen, that is, proportion of AZT users in the clinical record correctly identified in electronic record, and specificity of severe anemia, that is, proportion of non‐cases of severe anemia in the clinical records correctly identified in the electronic record. Kappa and intraclass correlation coefficients were used to determine reliability.

Results

A total of 12 358 records were selected from EDT. Seventy‐six percent and 58% of EDT records were linked to ePMS and MEDITECH, respectively. The sensitivity of the starting HAART regimen was 98%, whereas specificity of severe anemia was 100%. The reliability scores for variables including weight, hemoglobin, and CD4 counts were moderate to perfect and ranged from 0.59 to 0.99.

Conclusion

Probabilistic record linkage methods were effective for records linkage in this sub‐Saharan African setting. Copyright © 2011 John Wiley & Sons, Ltd.
Twists and turns in ubiquitin‐like protein conjugation cascades
Authors: Schulman Brenda A.
Published: October 2011

Post‐translational modification by ubiquitin‐like proteins (UBLs) is a predominant eukaryotic regulatory mechanism. The vast reach of this form of regulation extends to virtually all eukaryotic processes that involve proteins. UBL modifications play critical roles in controlling the cell cycle, transcription, DNA repair, stress responses, signaling, immunity, plant growth, embryogenesis, circadian rhythms, and a plethora of other pathways. UBLs dynamically modulate target protein properties including enzymatic activity, conformation, half‐life, subcellular localization, and intermolecular interactions. Moreover, the enzymatic process of UBL ligation to proteins is itself dynamic, with the UBL moving between multiple enzyme active sites and ultimately to a target. This review highlights our work on how the dynamic conformations of selected enzymes catalyzing UBL ligation help mediate this fascinating form of protein regulation.
Dominant phonon wavevectors of the 2D Raman mode of graphene
Authors: Narula Rohit , Bonini Nicola , Marzari Nicola , Reich Stephanie
Published: October 2011

We investigate the dominant phonon wavevectors q* and the associated dominant phonon‐assisted electronic transitions implied by the 2D Raman mode of graphene by combining ab initio calculations with a full two‐dimensional integration over the graphene Brillouin zone. We find that q* are highly anisotropic and rotate with the polarizer:analyzer condition, providing access to the entire angular extent around K. The resonant electronic transitions do not lie along the ${\bf K}- {\bf M}- {\bf K'}$ line and can be transformed from being apparently “inner” to “outer” with the addition of a reciprocal lattice vector, showing that both are equivalent. We thus invalidate the notion of “inner” and “outer” processes completely.
Site preference of magnetic atoms in Ni–Mn–Ga–M (M = Co, Fe) ferromagnetic shape memory alloys
Authors: Ayila Satish Kumar , Machavarapu Ramudu , Vummethala Seshubai
Published: October 2011

Site preference of cobalt and iron atoms substituted in Ni–Mn–Ga alloys is examined using the compositional dependence of saturation magnetization determined at 5 K. Variations in magnetization of Ni50Mn25+xGa25−x−yMy(M = Co, Fe) alloys are systematically compared with the values computed for different possible configurations of site occupancies. The study reveals that the dopant atoms occupy the regular Mn site, rather than the vacant Ga site, with ferromagnetic exchange relative to the moments on Ni and Mn sublattices. The excess and displaced Mn atoms occupy the vacant Ga site with antiferromagnetic exchange. Site preference appears to have a correlation to the atomic volume of the elements.
Electronic structure and optical absorbance of doped amorphous silicon slabs
Authors: Ramirez Jessica J. , Kilin Dmitri S. , Micha David A.
Published: October 2011

The absorption of light by doped amorphous silicon (a‐Si) slabs, in the far IR to near UV spectral range, has been calculated using molecular dynamics and density functional theory for extended systems. Our systems were modeled by supercells and with periodic boundary conditions. A series of 10‐layer, each with 6 × 4 Si atoms, a‐Si models were generated via simulated melting and quenching, followed by passivation of the top and bottom surfaces by hydrogen atoms. Our supercells were constructed with substitutional doping of Si lattice atoms, at densities of about 0.5–1.0% dopant atoms per surface unit, converting the a‐Si slabs into either p‐type (using Group III elements: B, Al, Ga) or n‐type (using Group V elements: N, P, As) systems. Results obtained include geometry conformations, density of states, electronic band gaps, and excitation spectra. They have been compared with previously obtained values for crystalline versions (c‐Si) of the systems mentioned above. We find that for both the amorphous and crystalline sets, doping reduces the bandgap from the pure silicon value, as acceptor/donor levels are introduced by defects into the Si bandgap region. This also reduces the HOMO‐LUMO energy gaps and allows for absorption at new wavelengths. Compared to pure Si, doping appears to significantly increase absorption intensity for lower‐energy radiation, as well as induce the wavelength of the absorption maximum to red‐shift. Computational investigations of this type provide fundamental insight on properties of materials pertinent to photovoltaic devices. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Robust synchronization of complex switched networks with parametric uncertainties and two types of delays
Authors: Wang Yan‐Wu , Bian Tao , Xiao Jiang‐Wen , Huang Yuehua
Published: October 2011

In this paper, a complex switched network (CSN) with parametric uncertainties and two types of time‐varying delays is presented. The CSN contains switching behaviors on both its nodes and the network topology. Different from those CSNs studied in the literatures, the switching mode dominating the nodes systems is independent with that dominating the network topology. The two types of time‐varying delays are the system delay in the node and the coupling delay between nodes and they have different values. The inherent synchronization properties of the CSN were investigated not subject to any controllers, and sufficient conditions for the global robust exponential synchronizations are obtained by defining a piecewise Lyapunov–Krasovskii function. Both the case with known derivative of delays and the case with unknown or nonexistent derivative of delays are investigated. Two special cases, i.e. the network without coupling delay and the network without switching behaviors and coupling delay, are studied. Illustrated examples are presented to show the effectiveness of the proposed methods. Copyright © 2011 John Wiley & Sons, Ltd.
Text split‐based steganography in OOXML format documents for covert communication
Authors: Fu Zhangjie , Sun Xingming , Liu Yuling , Li Bo
Published: October 2011

A new steganographic method for data hiding in Microsoft Word 2007–2010 (Microsoft Corp., Redmond, WA, USA) files that use Office Open XML (OOXML) format is proposed. Secret information can be imperceptibly embedded into OOXML documents by splitting up the printable text, which is defined by the main document body of the OOXML format document. The number of printable words contained in each segment represents the secret message. Theoretical analysis demonstrates that embedding bit rate of the proposed method can take the maximum value (0.8) when 2 bits of secret message are embedded into each segment. Experiments show that 0.44 bit is embedded into each word and 1/151 bit is embedded into each bit of the document on average, which is higher than contemporary linguistic steganography approaches. The method can resist “Format”, “Impersonation”, “Save As”, “Copy”, and other active attacks, and all these changes will not be shown on the MS Office screen display. Therefore, the proposed method can apply to the fields of covert communication and security protection for OOXML format documents. Copyright © 2011 John Wiley & Sons, Ltd.
Highly Luminescent Metal–Organic Frameworks Through Quantum Dot Doping
Authors: Buso Dario , Jasieniak Jacek , Lay Matthew D. H. , Schiavuta Piero , Scopece Paolo , Laird Jamie , Amenitsch Heinz , Hill Anita J. , Falcaro Paolo
Published: October 2011

The incorporation of highly luminescent core–shell quantum dots (QDs) within a metal–organic framework (MOF) is achieved through a one‐pot method. Through appropriate surface functionalization, the QDs are solubilized within MOF‐5 growth media. This permits the incorporation of the QDs within the evolving framework during the reaction. The resulting QD@MOF‐5 composites are characterized using X‐ray fluorescence, cross‐sectional confocal microscopy, energy‐dispersive X‐ray spectroscopy, scanning electron microscopy, and small‐angle X‐ray scattering. The synergistic combination of luminescent QDs and the controlled porosity of MOF‐5 in the QD@MOF‐5 composites is harnessed within a prototype molecular sensor that can discriminate on the basis of molecular size.
Hierarchical Nanoparticle Bragg Mirrors: Tandem and Gradient Architectures
Authors: Redel Engelbert , Huai Chen , Renner Michael , von Freymann Georg , Ozin Geoffrey A.
Published: October 2011

To manipulate electrons in semiconductor electronic and optical devices, the usual approach is through materials composition, electronic bandgap, doping, and interface engineering. More advanced strategies for handling electrons in semiconductor devices include composition‐controlled heterostructures and gradient structures. By analogy to the manipulation of electrons in semiconductor crystals by electronic bandgaps, photons in photonic crystals can be managed using photonic bandgaps. In this context, the simplest photonic crystal is the Bragg mirror, a periodic dielectric construct whose photonic bandgap is engineered through variations of the optical thickness of its constituent layers. Traditionally the materials comprising these periodic dielectric layers are nonporous, and they have mainly been used in the field of optical and photonic devices. More recently these Bragg mirrors have been made porous by building the layers from nanoparticles with functionality and utility that exploit their internal voids. These structures are emerging in the area of photonic color‐coded chemical sensing and controlled chemical release. Herein, a strategy for enhancing the functionality and potential utility of nanoparticle Bragg mirrors by making the constituent dielectric layers aperiodic and porous is described. It is exemplified by prototypical tandem and gradient structures that are fully characterized with regards to their structure, porosity, and optical and photonic properties.
DNA damage and repair following In vitro exposure to two different forms of titanium dioxide nanoparticles on trout erythrocyte
Authors: Sekar Durairaj , Falcioni Maria Letizia , Barucca Gianni , Falcioni Giancarlo
Published: October 2011

TiO2 has been widely used to promote organic compounds degradation on waste aqueous solution, however, data on TiO2 nanotoxicity to aquatic life are still limited. In this in vitro study, we compare the toxicity of two different families of TiO2 nanoparticles on erythrocytes from Oncorhynchus mykiss trout. The crystal structure of the two TiO2 nanoparticles was analyzed by XRD and the results indicated that one sample is composed of TiO2 in the anatase crystal phase, while the other sample contains a mixture of both the anatase and the rutile forms of TiO2 in a 2:8 ratio. Further characterization of the two families of TiO2 nanoparticles was determined by SEM high resolution images and BET technique. The toxicity results indicate that both TiO2 nanoparticles increase the hemolysis rate in a dose dependent way (1.6, 3.2, 4.8 μg mL−1) but they do not influence superoxide anion production due to NADH addition measured by chemiluminescence. Moreover, TiO2 nanoparticles (4.8 μg mL−1) induce DNA damage and the entity of the damage is independent from the type of TiO2 nanoparticles used. Modified comet assay (Endo III and Fpg) shows that TiO2 oxidizes not only purine but also pyrimidine bases. In our experimental conditions, the exposure to TiO2 nanoparticles does not affect the DNA repair system functionality. The data obtained contribute to better characterize the aqueous environmental risks linked to TiO2 nanoparticles exposure. © 2011 Wiley Periodicals, Inc. Environ Toxicol 29: 117–127, 2014.
Considering anger from a cognitive neuroscience perspective
Authors: Blair R. J. R.
Published: October 2011

The goal of this paper is to consider anger from a cognitive neuroscience perspective. Five main claims are made: first, reactive aggression is the ultimate behavioral expression of anger and thus we can begin to understand anger by understanding reactive aggression. Second, neural systems implicated in reactive aggression (amygdala, hypothalamus, and periaqueductal gray; the basic threat system) are critically implicated in anger. Factors such as exposure to extreme threat that increase the responsiveness of these systems, should be (and are in the context of posttraumatic stress disorder), associated with increased anger. Third, regions of frontal cortex implicated in regulating the basic threat system, when dysfunctional (e.g., in the context of lesions) should be associated with increased anger. Fourth, frustration occurs when an individual continues to do an action in the expectation of a reward but does not actually receive that reward, and is associated with anger. Individuals who show impairment in the ability to alter behavioral responding when actions no longer receive their expected rewards should be (and are in the context of psychopathy) associated with increased anger. Fifth, someone not doing what another person wants them to do (particularly if this thwarts the person's goal) is frustrating and consequently anger inducing. The response to such a frustrating social event relies on the neural architecture implicated in changing behavioral responses in nonsocial frustrating situations.WIREs Cogn Sci2012, 3:65–74. doi: 10.1002/wcs.154

This article is categorized under:

Psychology > Brain Function and Dysfunction
Group 1 metabotropic glutamate receptors and schizophrenia
Authors: de Bartolomeis Andrea , Szumlinski Karen Kathleen
Published: October 2011

Schizophrenia is a prevalent neuropsychiatric disorder associated with perturbations in medial prefrontal cortex (PFC) excitability and connectivity. As such, research into the neurobiology of schizophrenia and related psychotic disorders has focused on understanding the possible role played by the major excitatory neurotransmitter glutamate in mediating the cognitive and psychosocial impairments characteristic of this disease. Historically, the ionotropic NMDA glutamate receptor has received the greatest experimental attention in this regard. However, converging data point to Group 1 metabotropic glutamate receptors (mGluRs), as well as the Group 1 mGluR scaffolding protein Homer, as critical for normal psychomotor and cognitive function. Moreover, data derived primarily from behavioral pharmacological and genetic studies conducted in animal models of psychosis, suggest that dysregulation of Group 1 mGluR signaling may contribute to anomalies in neuronal excitation putatively underpinning the manifestation of cognitive abnormalities and psychotic‐like behavior. These data implicate targeting Group 1 mGluRs as viable pharmacotherapeutic strategies for the treatment of schizophrenia and related disorders. WIREs Membr Transp Signal 2012, 1:94–103. doi: 10.1002/wmts.15

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Functions of proton channels in phagocytes
Authors: Demaurex Nicolas
Published: October 2011

Phagocytes are immune cells that swallow microbes and degrade them with oxygen radicals produced by the phagocytic NADPH oxidase (phox), an enzyme that delivers electrons into the lumen of the phagocytic vacuole to produce toxic oxygen radicals. Voltage‐gated proton channels were long thought to sustain the activity of the phox by providing a compensating charge during electron transfer, and to minimize the cytosolic acidification caused by the activity of the phox. Voltage and pH recordings from neutrophils derived from voltage‐sensing only protein (VSOP)/voltage‐gated proton channel (Hv1) knock‐out mice confirmed that VSOP/Hv1 proton channels mitigate the depolarization and cytosolic acidification associated with the activity of the phox and revealed that VSOP/Hv1 proton channels sustain calcium signaling by maintaining a physiological membrane potential during phox activity, thereby increasing the driving force for the entry of cations across membrane channels. These mechanisms were demonstrated at the plasma membrane however, and whether VSOP/Hv1 proton channels contribute to the voltage and pH homeostasis of phagosomes, the major site of phox activation, has not been tested. VSOP/Hv1 channels might supply protons to the lumen of phagosomes and fuel the dismutation reaction that converts superoxide into hydrogen peroxide used for myeloperoxidase‐mediated halogenations or, instead, might remove protons from phagosomes and delay the phagosomal acidification caused by vacuolar ATPases. Future experiments will reveal whether VSOP/Hv1 channels move protons in or out of the phagocytic vacuole and maintain a permissive membrane potential that prevent the self‐inhibition of the phox and favor the efflux of calcium from phagosomes. WIREs Membr Transp Signal 2012, 1:3–15. doi: 10.1002/wmts.2

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Supporting the cell, supporting the science: an editorial essay
Authors: Verkhratsky Alexei , Nedergaard Maiken
Published: October 2011

WIREs Membr Transp Signal 2012, 1:1–2. doi: 10.1002/wmts.31

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Metal Derivatives of Heterocyclic‐2‐thiones: Crystal Structures of [Bis(diphenylphosphanyl)propane][bis(pyrimidine‐2‐thiolato)]ruthenium(II) and [Bis(diphenylphosphanyl)methane][bis(pyridine‐2‐thiolato)]ruthenium(II)
Authors: Lobana Tarlok S. , Kaur Parminderjit , Kaur Amanpreet , Butcher Ray J.
Published: October 2011

Ruthenium(II) Complexes containing pyrimidine‐2‐thiolate (pymS–) and bis(diphenylphosphanyl)alkanes [Ph2P–(CH2)m–PPh2, m = 1, dppm; m = 2, dppe; m = 3, dppp; m = 4, dppb] are described. Reactions of [RuCl2L2] (L = dppm, dppp) and [Ru2Cl4L3] (L = dppb) with pyrimidine‐2‐thione (pymSH) in 1:2 molar ratio in dry benzene in the presence of Et3N base yielded the [Ru(pymS)2L] complexes (pymS– = pyrimidine‐2‐thiolate; L = dppm (1); dppp (3); dppb (4)). The complex [Ru(pymS)2(dppe)] (2) was indirectly prepared by the reaction of [Ru(pymS)2(PPh3)2] with dppe. These complexes were characterized using analytical data, IR, 1H, 13C, 31P NMR spectroscopy, and X‐ray crystallography (complex 3). The crystal structure of the analogous complex [Ru(pyS)2(dppm)] (5) with the ligand pyridine‐2‐thiolate (pyS–) was also described. X‐ray crystallographic investigation of complex 3 has shown two four‐membered chelate rings (N, S donors) and one six‐membered ring (P, P donors) around the metal atom. Compound 5 provides the first example in which RuII has three four‐membered chelate rings: two made up by N, S donor ligands and one made up by P, P donor ligand. The arrangement around the metal atoms in each complex is distorted octahedral with cis:cis:trans:P, P:N, N:S, S dispositions of the donor atoms. The 31P NMR spectroscopic data revealed that the complexes are static in solution, except 2, which showed the presence of more than one species.
Synthesis and Magnetic Properties of Two New Cobalt Complexes Constructed by Semirigid V‐shaped 5‐(4‐Carboxyphenoxy)‐pyridine‐2‐carboxylic Acid
Authors: Song Jiang‐Feng , Zhou Rui‐Sha , Zhang Jia , Pan Cheng‐Ling
Published: October 2011

Two cobalt complexes, [Co3(L)2(CH3OH)2(μ3‐OH)2] (1) and [Co(L)(bpe)0.5]·H2O (2) [H2L = 5‐(4‐carboxyphenoxy)‐pyridine‐2‐carboxylic acid; bpe = 1, 2‐bis(4‐pyridyl)ethylene] were synthesized and fully characterized by elemental analyses, IR spectroscopy, single‐crystal X‐ray diffraction, thermogravimetric analysis (TGA), and magnetic analysis. Complex 1 has a two‐dimensional (2D) structure with puckered Co–O–Co chains, and 2 displays a three‐dimensional (3D) network containing one‐dimensional rectangular channels with dimensions of 9.24 × 13.84 Å. In complex 1, variable‐temperature magnetic susceptibility measurements indicate antiferromagnetic interactions between cobalt magnetic centers.
Synthesis of a Water‐Stable 2, 4‐Bis(trifluoromethyl)phenyl‐Substituted Phosphonous Acid Palladium Complex and its Catalytic Activity in Cross‐Coupling Reactions
Authors: Kurscheid Boris , Stammler Hans‐Georg , Neumann Beate , Hoge Berthold
Published: October 2011

This manuscript describes the selective synthesis of2, 4‐bis(trifluoromethyl)phenylphosphinic acid, (Rf)P(O)(H)OH.Reaction of chlorobis(diethylamino)phosphane with a mixture of 2, 4‐(CF3)2C6H3Li and 2, 6‐(CF3)2C6H3Li results in the formation of 2, 4‐bis(trifluoromethyl)phenylbis(diethylamino)phosphane, (Rf)P(NEt2)2. The following in situ reaction with gaseous HBr leads to the cleavage of the phosphorus nitrogen bonds resulting in the selective formation of the corresponding dibromophosphane (Rf)PBr2.2, 4‐Bis(trifluoromethyl)phenylphosphinic acid is available via two different synthetic strategies starting from the dibromophosphane (Rf)PBr2. Reduction of the dibromophosphane with tributyltin hydride affords selectively the phosphane (Rf)PH2. The following oxidation to the phosphinic acid (Rf)P(O)(H)OH, however, only proceeds in moderate yields. A more efficient synthesis is achieved via the hydrolysis of the dibromophosphane (Rf)PBr2 in dichloromethane solution. 2, 4‐bis(trifluoromethyl)phenylphosphinic acid, (Rf)P(O)(H)OH, is surprisingly stable towards air and water. The water soluble phosphinic acid reacts sluggishly with a 30 % H2O2 solution, yielding only 23 % of the corresponding phosphonic acid (Rf)P(O)(OH)2 after seven days at ambient temperature.In principle a tautomerization of the phosphinic acid (Rf)P(O)(H)OH to the corresponding phosphonous acid (Rf)P(OH)2 – analogously to the phosphane oxide (Rf)2P(O)H and the phosphinous acid (Rf)2POH – is conceivable. However, the phosphonous acid could not be detected with spectroscopic methods. The energy difference between the phosphinic acid and the phosphonous acid is calculated by quantum chemical calculations at the B3LYP/6‐311+G(2df, p) level of theory to 30.1 kJ·mol–1. This high value explains why the phosphonous acid tautomer could not be detected by spectroscopic methods so far.As transition metal complexes featuring phosphonous acid ligands are of significant interest for the application as homogeneous catalysts we studied the coordination chemistry of the related phosphinic acid in more detail. The preligand 2, 4‐bis(trifluoromethyl)phenylphosphinic acid reacts smoothly with palladium dichloride in THF to the dinuclear complex [Pd2(μ‐Cl)2{[2, 4‐(CF3)2C6H3P(OH)O]2H}2], featuring a phosphonous acid phosphonato unit, with a strong hydrogen bridge substantiated by an O···O distance of 247.7(3) pm. The dinuclear phosphonous acid palladium complex exhibits a high catalytic activity in the Suzuki cross‐coupling. Alternatively, the phosphinic acid can be used as preligand for the in situ formation of a phosphonous acid palladium complex. These compounds combine catalytic activity with a very high stability towards air and water.
Rotational Head Kinematics in Football Impacts: An Injury Risk Function for Concussion
Authors: Rowson Steven , Duma Stefan M. , Beckwith Jonathan G. , Chu Jeffrey J. , Greenwald Richard M. , Crisco Joseph J. , Brolinson P. Gunnar , Duhaime Ann-Christine , McAllister Thomas W. , Maerlender Arthur C.
Published: October 2011

Recent research has suggested a possible link between sports-related concussions and neurodegenerative processes, highlighting the importance of developing methods to accurately quantify head impact tolerance. The use of kinematic parameters of the head to predict brain injury has been suggested because they are indicative of the inertial response of the brain. The objective of this study is to characterize the rotational kinematics of the head associated with concussive impacts using a large head acceleration dataset collected from human subjects. The helmets of 335 football players were instrumented with accelerometer arrays that measured head acceleration following head impacts sustained during play, resulting in data for 300,977 sub-concussive and 57 concussive head impacts. The average sub-concussive impact had a rotational acceleration of 1230 rad/s2 and a rotational velocity of 5.5 rad/s, while the average concussive impact had a rotational acceleration of 5022 rad/s2 and a rotational velocity of 22.3 rad/s. An injury risk curve was developed and a nominal injury value of 6383 rad/s2 associated with 28.3 rad/s represents 50% risk of concussion. These data provide an increased understanding of the biomechanics associated with concussion and they provide critical insight into injury mechanisms, human tolerance to mechanical stimuli, and injury prevention techniques.