bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal oxidative stability analysis of hoki and tuna oils by Differential Scanning Calorimetry and Thermogravimetry
Authors: Tengku‐Rozaina Tengku Mohamad , Birch Edward John
Published: September 2015

In this study, oxidative stability of hoki and tuna oils were measured at 80°C by Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA) under an air atmosphere. The onset time for oxidation (to) of hoki oil occurred earlier in the TGA (222.50 min) compared to DSC (640.83 min) as the sample gained weight prior to decomposition. Conversely, the to of tuna oil could not be recorded since tuna oil was rapidly oxidized. The predicted shelf life of hoki oil for onset of oxygen uptake and subsequent decomposition at 4°C, by Arrhenius extrapolation of TGA and DSC under different isothermal treatments were 0.56 and 1.39 years, respectively. Temperature programmed decomposition of hoki and tuna oils by TGA occurred in three thermal stages, suggesting a progressive degradation of polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA), and saturated fatty acids (SFA), followed by volatilization of polymerization and pyrolysis products.

Practical applications: Fish oil has been marketed as dietary supplements and as an ingredient for food products. However, these products are susceptible to oxidation due to the high‐PUFA content in fish oil. Oxidative and thermal stability of fish oil are important parameters in the processing and production of fish oil and fish oil fortified food products. These data can be used by fish oil and food manufacturers to optimize processing conditions for fish oil and food products fortified with fish oil. The oxidative stability of fish oils over temperature ranges and storage times can be measured by both isothermal and non‐isothermal DSC and TGA analyses. These techniques are more rapid and provide continuous data compared to conventional shelf life studies and alternative instrumental methods. Shelf life of the fish oils can be predicted by an Arrhenius extrapolation from elevated isothermal DSC and TGA analyses.

Measurement of oxidative stability of fish oils by DSC and TGA follow the Q10 law on the relationship between temperature and rate of chemical reaction. Prediction of shelf life of the fish oils is possible by an Arrhenius extrapolation from elevated isothermal DSC and TGA analyses. Differences in the thermal behavior of the fish oils were consistent with major fatty acid compositional differences.
Shake table testing of un‐reinforced brick masonry building test model isolated by U‐FREI
Authors: Das Animesh , Deb Sajal Kanti , Dutta Anjan
Published: September 2015

This paper presents a detailed study on feasibility of un‐bonded fiber reinforced elastomeric isolator (U‐FREI) as an alternative to steel reinforced elastomeric isolator (SREI) for seismic isolation of un‐reinforced masonry buildings. Un‐reinforced masonry buildings are inherently vulnerable under seismic excitation, and U‐FREIs are used for seismic isolation of such buildings in the present study. Shake table testing of a base isolated two storey un‐reinforced masonry building model subjected to four prescribed input excitations is carried out to ascertain its effectiveness in controlling seismic response. To compare the performance of U‐FREI, same building is placed directly on the shake table without isolator, and fixed base (FB) condition is simulated by restraining the base of the building with the shake table. Dynamic response characteristic of base isolated (BI) masonry building subjected to different intensities of input earthquakes is compared with the response of the same building without base isolation system. Acceleration response amplification and peak response values of test model with and without base isolation system are compared for different intensities of table acceleration. Distribution of shear forces and moment along the height of the structure and response time histories indicates significant reduction of dynamic responses of the structure with U‐FREI system. This study clearly demonstrates the improved seismic performance of un‐reinforced masonry building model supported on U‐FREIs under the action of considered ground motions. Copyright © 2015 John Wiley & Sons, Ltd.
Metrics for quantifying anthropogenic impacts on geomorphology: road networks
Authors: Sofia Giulia , Marinello Francesco , Tarolli Paolo
Published: September 2015

This work tests the capability of a recently published topographic index, the Slope Local Length of Auto‐correlation (SLLAC), to portrait and delineate anthropogenic geomorphologies. The patterns of the anthropogenic pressure are defined considering the road network density and the Urban Complexity Index (UCI). First, the research investigates the changes in the SLLAC in two derived parameters (average SLLAC and the SLLAC surface peak curvature – Spc – per km2) connected to the increasing of the anthropogenic structures. Next, natural and anthropogenic landscapes are clustered and classified. The results show that there is a direct correlation between the road network density and the UCI, and the mean SLLAC per km2. However, the Spc is inversely correlated with the anthropogenic pressure (network density and urban complexity). This shows that the surface morphology (slope) of regions presenting anthropogenic structures tends to be well organized (low Spc) and, in general, self‐similar at a long distance (higher average SLLAC). The results of the clustering approach show that the procedure can correctly depict anthropogenic landscapes having a road network density greater than about 3 km/km2, also in areas covered by vegetation. This latter result is promising for the use of such a procedure in regions that cannot be seen directly from orthophotos or satellite images. The proposed method can actively capture the alteration produced by road networks on surface morphology identifying different signatures of urban development: exploration and densification networks that are responsible for increasing the local density of the network and expanding the network into new areas, respectively. The effects of this alteration on surface processes could be significant for future research, creating new questions about differences due to human or landscape forcing on Earth surface processes. Copyright © 2015 John Wiley & Sons, Ltd.
Developmental evaluation of atypical auditory sampling in dyslexia: Functional and structural evidence
Authors: Lizarazu Mikel , Lallier Marie , Molinaro Nicola , Bourguignon Mathieu , Paz‐Alonso Pedro M. , Lerma‐Usabiaga Garikoitz , Carreiras Manuel
Published: September 2015

Whether phonological deficits in developmental dyslexia are associated with impaired neural sampling of auditory information at either syllabic‐ or phonemic‐rates is still under debate. In addition, whereas neuroanatomical alterations in auditory regions have been documented in dyslexic readers, whether and how these structural anomalies are linked to auditory sampling and reading deficits remains poorly understood. In this study, we measured auditory neural synchronization at different frequencies corresponding to relevant phonological spectral components of speech in children and adults with and without dyslexia, using magnetoencephalography. Furthermore, structural MRI was used to estimate cortical thickness of the auditory cortex of participants. Dyslexics showed atypical brain synchronization at both syllabic (slow) and phonemic (fast) rates. Interestingly, while a left hemispheric asymmetry in cortical thickness was functionally related to a stronger left hemispheric lateralization of neural synchronization to stimuli presented at the phonemic rate in skilled readers, the same anatomical index in dyslexics was related to a stronger right hemispheric dominance for neural synchronization to syllabic‐rate auditory stimuli. These data suggest that the acoustic sampling deficit in development dyslexia might be linked to an atypical specialization of the auditory cortex to both low and high frequency amplitude modulations. Hum Brain Mapp 36:4986–5002, 2015. © 2015 Wiley Periodicals, Inc.
Biomolecules in Metal and Semiconductor Nanoparticle Growth
Authors: Baumann Verena , Habeeb Muhammed Madathumpady Abubaker , Blanch Adam J. , Dey Priyanka , Rodríguez‐Fernández Jessica
Published: September 2015

Exerting control over the size, morphology, and complexity of metal and semiconductor nanoparticles and nanostructures is a requisite for exploring novel phenomena, and the potential applications of these nanomaterials. Bottom‐up colloidal chemistry syntheses can benefit from using biomolecules as active elements to influence the formation of inorganic nanoparticles. In this review, we will discuss how three main biomolecule types, (namely DNA; amino acids, peptides, and proteins; and enzymes), can affect the growth of metal and semiconductor nanoparticles. We will present and discuss the templating and non‐templating roles of those biomolecules, featuring key aspects and prospects of biomolecule‐assisted metal and semiconductor nanoparticle growth.
Tracking mesenchymal stromal cells using an ultra‐bright TAT‐functionalized plasmonic‐active nanoplatform
Authors: Yuan Hsiangkuo , Gomez Jose A. , Chien Jennifer S. , Zhang Lunan , Wilson Christy M. , Li Shuqin , Fales Andrew M. , Liu Yang , Grant Gerald A. , Mirotsou Maria , Dzau Victor J. , Vo‐Dinh Tuan
Published: September 2015

High‐resolution tracking of stem cells remains a challenging task. An ultra‐bright contrast agent with extended intracellular retention is suitable for in vivo high‐resolution tracking of stem cells following the implantation. Here, a plasmonic‐active nanoplatform was developed for tracking mesenchymal stromal cells (MSCs) in mice. The nanoplatform consisted of TAT peptide‐functionalized gold nanostars (TAT‐GNS) that emit ultra‐bright two‐photon photoluminescence capable of tracking MSCs under high‐resolution optical imaging. In vitro experiment showed TAT‐GNS‐labeled MSCs retained a similar differentiability to that of non‐labeled MSCs controls. Due to their star shape, TAT‐GNS exhibited greater intracellular retention than that of commercial Q‐Tracker. In vivo imaging of TAT‐GNS‐labeled MSCs five days following intra‐arterial injections in mice kidneys showed possible MSCs implantation in juxta‐glomerular (JG) regions, but non‐specifically in glomeruli and afferent arterioles as well. With future design to optimize GNS labeling specificity and clearance, plasmonic‐active nanoplatforms may be a useful intracellular tracking tool for stem cell research.

An ultra‐bright intracellular contrast agent is developed using TAT peptide‐functionalized gold nanostars (TAT‐GNS). It poses minimal influence on the stem cell differentiability. It exhibits stronger two‐photon photoluminescence and superior labeling efficiency than commercial Q‐Tracker. Following renal implantation, some TAT‐GNS‐labeled MSCs permeate blood vessels and migrate to the juxta‐glomerular region.

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An ultra‐bright intracellular contrast agent is developed using TAT peptide‐functionalized gold nanostars (TAT‐GNS). It poses minimal influence on the stem cell differentiability. It exhibits stronger two‐photon photoluminescence and superior labeling efficiency than commercial Q‐Tracker. Following renal implantation, some TAT‐GNS‐labeled MSCs permeate blood vessels and migrate to the juxta‐glomerular region.
Tumor Microenvironment Versus Cancer Stem Cells in Cholangiocarcinoma: Synergistic Effects?
Authors: Romano Maurizio , De Francesco Francesco , Gringeri Enrico , Giordano Antonio , Ferraro Giuseppe A. , Di Domenico Marina , Cillo Umberto
Published: September 2015

Cholangiocarcinoma (CCAs) may be defined as tumors that derived from the biliary tree with the differentiation in the biliary epithelial cells. This tumor is malignant, extremely aggressive with a poor prognosis. It can be treated surgically and its pathogenesis is poorly understood. The tumor microenvironment (TME) is a very important factor in the regulation of tumor angiogenesis, invasion, and metastasis. Besides cancer stem cells (CSCs) can modulate tumor growth, stroma formation, and migratory capability. The initial stage of tumorigenesis is characterized by genetic mutations and epigenetic alterations due to intrinsic factors which lead to the generation of oncogenes thus inducing tumorigenesis. CSCs may result from precancerous stem cells, cell de‐differentiation, normal stem cells, or an epithelial‐mesenchymal transition (EMT). CSCs have been found in the cancer niche, and EMT may occur early within the tumor microenvironment. Previous studies have demonstrated evidence of cholangiocarcinoma stem cells (CD133, CD24, EpCAM, CD44, and others) and the presence of these markers has been associated with malignant potential. The interaction between TME and cholangiocarcinoma stem cells via signaling mediators may create an environment that accommodates tumor growth, yielding resistance to cytotoxic insults (chemotherarapeutic). While progress has been made in the understanding of the mechanisms, the interactions in the tumorigenic process still remain a major challenge. Our review, addresses recent concepts of TME‐CSCs interaction and will emphasize the importance of early detection with the use of novel diagnostic mechanisms such as CCA–CSC biomarkers and the importance of tumor stroma to define new treatments. J. Cell. Physiol. 231: 768–776, 2016. © 2015 Wiley Periodicals, Inc.
Pregnancy‐induced changes in the pharmacokinetics of caffeine and its metabolites
Authors: Yu Tian , Campbell Sarah C. , Stockmann Chris , Tak Casey , Schoen Katherine , Clark Erin A. S. , Varner Michael W. , Spigarelli Michael G. , Sherwin Catherine M. T.
Published: September 2015

This study sought to assess the pharmacokinetic (PK) changes of caffeine and its CYP1A2 metabolites across the 3 trimesters of pregnancy. A prospective, multicenter PK study was conducted among 59 pregnant women (93.2% white) who were studied once during a trimester. One beverage with 30‐95 mg caffeine was consumed, and a blood/urine sample was collected within 1 hour postingestion. Concentrations of caffeine and its primary metabolites were quantified from serum and urine by LC‐MS/MS. There was a significant increase in dose‐normalized caffeine serum and urine concentrations between the first and third trimesters (P < .05 and P < .01, respectively). Normalized theophylline concentrations also increased significantly in the third trimester in serum (P < .001) and in urine (P < .05). The caffeine urine/serum concentration ratio also increased in the last trimester (P < .05). No significant difference was found in normalized paraxanthine or theobromine concentrations. This study identified decreased caffeine metabolism and an increase in the active metabolite theophylline concentrations during pregnancy, especially in the third trimester, revealing evidence of the large role that pregnancy plays in influencing caffeine metabolism.
Curing of plasmid pBMB28 from Bacillus thuringiensis YBT‐020 using an unstable replication region
Authors: Wang Pengxia , Zhu Qian , Shang Hui , Zhu Yiguang , Sun Ming
Published: September 2015

Bacillus thuringiensis serovar finitimus strain YBT‐020 is the well‐studied spore‐crystal association (SCA) phenotypic strain, whose parasporal crystals adhere to spore after lysis of the mother cell. Its endogenous plasmids pBMB26 and pBMB28 were proved essential for this SCA phenotype. In our previous study, using conventional methods, pBMB26 cured derivative and both pBMB26 and pBMB28 cured derivative of YBT‐020 were obtained. However, YBT‐020 solely cured of pBMB28 could not be obtained. In this study, an unstable replication region of pBMB28 was identified and was used to construct an incompatible plasmid pRep28B. This incompatible plasmid was successfully used to cure plasmid pBMB28 and was easily eliminated through segregational instability under the optimum growth temperature of YBT‐020. Therefore, an endogenous plasmid was cured from the B. thuringiensis strain utilizing plasmid incompatibility. Moreover, using an unstable replication region instead of a temperature sensitive (Ts) replication region is better to cure the incompatible plasmid because it can avoid culturing at higher temperature. This method provides an efficient method for plasmid curing in B. thuringiensis and other bacteria.
Some reflections on the evolution of meta‐analysis
Authors: Altman Douglas G.
Published: September 2015

I reflect on the evolution of meta‐analysis in clinical research over 35 years since I first encountered the key ideas in the late 1970s. Copyright © 2015 Douglas G. Altman.
Survey frequency and timing affect occupancy and abundance estimates for salt marsh birds
Authors: Wiest Whitney A. , Shriver W. Gregory
Published: September 2015

Salt marsh birds in eastern North America are high conservation priorities due to their restricted ranges, threats from sea‐level rise, and an overall lack of information related to their population status or trends. We calculated estimates of detection probabilities for clapper rail (Rallus crepitans), willet (Tringa semipalmata), seaside sparrow (Ammodramus maritimus), and saltmarsh sparrow (A. caudacutus) breeding in Delaware Bay, USA. Our objectives were to model the effects of survey covariates on detection probabilities for occupancy and abundance estimates, determine how survey frequency (no. visits to a site) and survey timing (when in the season sites are sampled) affected the estimates, and how varying the number and timing of visits affected the estimates compared to the recommendations based on the North American Marsh Bird Monitoring Protocol. To make these comparisons, we defined 4 survey frequency (2, 3, 4, and 8 visits) and 3 survey timing (early, early‐middle‐late, and late season) scenarios. Our results are based on 480 surveys (i.e., call broadcast point counts) to 30 sampling locations located at Bombay and Prime Hook National Wildlife Refuges during the 2008 and 2009 breeding seasons. The scenario of 3 visits early in the season provided the lowest error estimates of occupancy and abundance. Distributing the survey effort across the season, our early‐middle‐late scenario, provided high variance estimates and should be avoided when designing monitoring programs for these tidal marsh obligate species. © 2015 The Wildlife Society.
Utility of preoperative computed tomography and magnetic resonance imaging in adult and pediatric cochlear implant candidates
Authors: Tamplen Matthew , Schwalje Adam , Lustig Lawrence , Alemi Aurash S. , Miller Mia E.
Published: September 2015

Objectives/Hypothesis

Determine the utility of preoperative imaging in adult and pediatric cochlear implant candidates.

Study Design

Retrospective chart review.

Methods

Medical records of 101 consecutive adult and 20 consecutive pediatric patients who underwent 137 cochlear implantation (CI) procedures at a single institution were reviewed.

Results

Computed tomography (CT) was obtained preoperatively in 110 (90.9%) patients, preoperative magnetic resonance imaging (MRI) was obtained in 102 (84.3%) patients, and both were obtained in 94 (77.7%) patients. MRI revealed one acoustic neuroma and two meningiomas, which affected surgical planning for three (2.2%) procedures. MRI identified enlarged vestibular aqueduct (EVA) in 2.0% of adult patients. CT demonstrated middle ear disease in four (3.3%) patients. CT was useful in indicating round window and cochlear patency in three (2.2%) patients with cochlear otosclerosis. Twenty pediatric patients underwent 27 CI procedures. Preoperative CT in the pediatric cohort demonstrated five (25%) dysplastic cochleae, three (15%) dysplastic vestibules and/or semicircular canals, and three (15%) EVAs. In one patient, CT demonstrated a duplicated right internal auditory canal (IAC) and hypoplastic left IAC; MRI confirmed hypoplastic cochlear nerves.

Conclusions

Preoperative MRI can demonstrate retrocochlear pathology, cochlear patency, and EVA in adults being evaluated for cochlear implantation. CT may provide additional information in patients with chronic otitis media or otosclerosis. However, in postlingually deafened adults without conductive or asymmetrical hearing loss, imaging is unlikely to affect surgical decision making. Both CT and MRI can identify anomalies in pediatric patients. MRI does not offer substantial benefit over CT for routine evaluation of pediatric inner ear and temporal bone anatomy.

Level of Evidence

4 Laryngoscope, 126:1440–1445, 2016
Bacteria‐based branched structures for bionanophotonics
Authors: Xin Hongbao , Li Yuchao , Li Baojun
Published: September 2015

Branched photonic structures have served as paramount important components for nanophotonic integration and circuitry. However, these structures are generally constructed with photonic and plasmonic nanowires, which are nonbiomaterials and often need to be specially engineered to interface with cells and biological system. For bionanophotonics, photonic components assembled with self‐adaptive biomaterials are highly desirable to be directly interfaced with the dynamic biological system. In this work, branched structures for bionanophotonics assembled with natural living biomaterials, i.e., nanorod‐shaped Escherichia coli bacteria are reported. The E. coli cells were orderly trapped using a specially desired tapered optical fiber, forming structures with different branches and lengths. Light‐propagation performances along these branched structures were investigated, and the robustness property of the structures were demonstrated. The results show that the bacteria‐based branched structures provide different promising self‐sustainable and evolvable components, such as multidirectional waveguides and beam splitters, for bionanophotonics by connecting the biological and optical worlds with a seamless interface.

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Determination of Factors Influencing the Wet Etching of Polydimethylsiloxane Using Tetra‐n‐butylammonium Fluoride
Authors: Kleiman Maya , Ryu Keun Ah , Esser‐Kahn Aaron P.
Published: September 2015

Polydimethyl siloxane (PDMS) is the most widely used polymer in microfluidic devices. Microfluidic devices are used in all ranges of science. The microstructure of a microfluidic device influences its efficiency. One method for controlling microstructure is through wet etching. A particularly common etchant is tetrabutylammonium fluoride (TBAF). This report shows that the etching rate of PDMS by a TBAF solution is controlled by the solvent in use. This report presents that solvent dictates interplay between the reactivity of the naked fluoride with the SiO bonds in the polymer chain and the solubility of the polymer chains. Both high reactivity and accessibility are necessary for a high etching rate. This gives a simple method to control the etching rate of PDMS and by that the microstructure of the microfluidic device.

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On parameterizations of plane rational curves and their syzygies
Authors: Bernardi A. , Gimigliano A. , Idà M.
Published: September 2015

Let C be a plane rational curve of degree d and be its normalization. We are interested in the splitting type of C, where gives the syzigies of the ideal , and   is a parameterization of C. We want to describe in which cases (, via a geometric description; namely we show that if and only if C is the projection of a rational curve on a rational normal surface in .
Phenacyl Ethyl Carbazolium as a Long Wavelength Photoinitiator for Free Radical Polymerization
Authors: Kara Merve , Dadashi‐Silab Sajjad , Yagci Yusuf
Published: September 2015

A new phenacyl‐type photoinitiator based on ethyl carbazole as a long wavelength photo­initiator is developed for free radical polymerization. Phenacyl ethyl carbazolium hexafluoroantimonate (PECH) photoinitiator is synthesized in a two‐step, one‐pot manner by quaternizing ethyl carbazole with phenacyl bromide and subsequent ion exchange reaction with potassium hexafluoroantimonate. Under irradiation, PECH tends to undergo homolytic bond cleavage bringing about initiating free radicals. However, as evidenced by cyclic voltammetry and real‐time photobleaching studies, formation of initiating cationic species is highly unlikely as the photochemically formed charged carbazole units tend to couple.

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6‐Shogaol exerts anti‐proliferative and pro‐apoptotic effects through the modulation of STAT3 and MAPKs signaling pathways
Authors: Kim Sung‐Moo , Kim Chulwon , Bae Hang , Lee Jong Hyun , Baek Seung Ho , Nam Dongwoo , Chung Won‐Seok , Shim Bum Sang , Lee Seok‐Geun , Kim Sung‐Hoon , Sethi Gautam , Ahn Kwang Seok
Published: September 2015

6‐shogaol (6SG), one of active ingredients in ginger (Zingiber officinale), is known to exhibit anti‐proliferative, anti‐metastatic, and pro‐apoptotic activities through a mechanism that is not fully elucidated. Because the aberrant activation of STAT3 and MAPKs have been associated with regulation of proliferation, invasion, and metastasis of tumors, we hypothesized that 6SG modulates the activation of STAT3 and MAPKs activation in tumor cells. We found that 6SG strongly inhibited constitutive phosphorylation of STAT3 through inhibition of the activation of upstream JAK2 and c‐Src kinases and nuclear translocation of STAT3 on both MDA‐MB231 and DU145 cells. Also, 6SG caused the activation of JNK, p38 MAPK, and ERK. Inhibition of ROS generation by N‐acetylcysteine (NAC) significantly prevented 6SG‐induced apoptosis. 6SG induced apoptosis as characterized by cleavage of PARP, accumulation of cells in subG1 phase, positive Annexin V binding, down‐regulation of STAT3‐regulated proteins, and activation of caspase‐8, ‐9, ‐3 in both MDA‐MB231 cells. Compared with other analogues of 6SG, such as 6‐gingerol (6G), 8‐gingerol (8G), and 10‐gingerol (10G), 6SG was found to be the most potent blocker of STAT3 activation. We observed that the administration of 6SG alone significantly suppressed the growth of the tumor. As compared to the vehicle control, 6SG also suppressed the expression of STAT3‐regulated gene products such as Bcl‐2, Bcl‐xL, and Survivin in tumor tissues. Overall, these findings suggest that 6SG can interfere with multiple signaling cascades involved in tumorigenesis and can be used as a potential therapeutic candidate for both the prevention and treatment of cancer. © 2014 Wiley Periodicals, Inc.
Strategies for the Optimization of Natural Leads to Anticancer Drugs or Drug Candidates
Authors: Xiao Zhiyan , Morris‐Natschke Susan L. , Lee Kuo‐Hsiung
Published: September 2015

Natural products have made significant contribution to cancer chemotherapy over the past decades and remain an indispensable source of molecular and mechanistic diversity for anticancer drug discovery. More often than not, natural products may serve as leads for further drug development rather than as effective anticancer drugs by themselves. Generally, optimization of natural leads into anticancer drugs or drug candidates should not only address drug efficacy, but also improve absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles and chemical accessibility associated with the natural leads. Optimization strategies involve direct chemical manipulation of functional groups, structure–activity relationship directed optimization and pharmacophore‐oriented molecular design based on the natural templates. Both fundamental medicinal chemistry principles (e.g., bioisosterism) and state‐of‐the‐art computer‐aided drug design techniques (e.g., structure‐based design) can be applied to facilitate optimization efforts. In this review, the strategies to optimize natural leads to anticancer drugs or drug candidates are illustrated with examples and described according to their purposes. Furthermore, successful case studies on lead optimization of bioactive compounds performed in the Natural Products Research Laboratories at UNC are highlighted.
Bifurcation analysis of the HIV‐1 within host model
Authors: Rahmoun Amel , Benmerzouk Djamila , Ainseba Bedreddine
Published: September 2015

In this paper, a bifurcation solution's analysis is proposed for an HIV‐1 within the host model around its chronic equilibrium point, this is carried out based on Lyapunov–Schmidt approach. It is shown that the coefficient b, which represents the healthy CD4+ T‐cells growth rate, is a bifurcation parameter; this means that the rate of multiplication of healthy cells can have serious effects on the qualitative dynamical properties and structural stability of the infection evolution dynamics. Copyright © 2015 John Wiley & Sons, Ltd.
Fueter's theorem in discrete Clifford analysis
Authors: Ridder Hilde De , Sommen Frank
Published: September 2015

In this paper, we discretize techniques for the construction of axially monogenic functions to the setting of discrete Clifford analysis. Wherefore, we work in the discrete Hermitian Clifford setting, where each basis vector ej is split into a forward and backward basis vector:
. We prove a discrete version of Fueter's theorem in odd dimension by showing that for a discrete monogenic function f(ξ0,ξ1) left‐monogenic in two variables ξ0 and ξ1 and for a left‐monogenic Pk(ξ), the m‐dimensional function
is in itself left monogenic, that is, a discrete function in the kernel of the discrete Dirac operator. Closely related, we consider a Vekua‐type system for the construction of axially monogenic functions. We consider some explicit examples: the discrete axial‐exponential functions and the discrete Clifford–Hermite polynomials. Copyright © 2015 John Wiley & Sons, Ltd.
Weighted Lp‐theory for vector potential operators in three‐dimensional exterior domains
Authors: Louati Hela , Meslameni Mohamed , Razafison Ulrich
Published: September 2015

In the present paper, we study the vector potential problem in exterior domains of
. Our approach is based on the use of weighted spaces in order to describe the behavior of functions at infinity. As a first step of the investigation, we prove important results on the Laplace equation in exterior domains with Dirichlet or Neumann boundary conditions. As a consequence of the obtained results on the vector potential problem, we establish useful results on weighted Sobolev inequalities and Helmholtz decompositions of weighted spaces. Copyright © 2015 John Wiley & Sons, Ltd.
Skeletal muscle fiber characteristics and oxidative capacity in hemiparetic stroke survivors
Authors: Severinsen Kaare , Dalgas Ulrik , Overgaard Kristian , Pedersen Asger R. , øRtenblad Niels , Lund Caroline , Jakobsen Johannes K. , Andersen Henning
Published: September 2015

Introduction: Skeletal muscle is changed after stroke, but conflicting data exist concerning muscle morphology and oxidative enzyme capacity. Methods: In 36 chronic stroke patients bilateral rectus femoris muscle biopsies were analyzed, and fiber type proportions and cross‐sectional areas were determined by ATPase histochemistry. Enzymatic concentrations of citrate synthase (CS) and 3‐Hydroxyacyl‐coenzymeA‐dehydrogenase (HAD) were determined using freeze‐dried muscle tissue. Findings were correlated with clinical outcomes. Results: In the paretic muscles the mean fiber area was smaller (P = 0.0004), and a lower proportion of type 1 fibers (P = 0.0016) and a higher proportion of type 2X fibers (P = 0.0002) were observed. The paretic muscle had lower CS (P = 0.013) and HAD concentrations (P = 0.037). Mean fiber area correlated with muscle strength (r = 0.43; P = 0.041), and CS concentration correlated with aerobic capacity (r = 0.47; P = 0.01). Conclusions: In stroke survivors there is a phenotypic shift toward more fatigable muscle fibers with reduced oxidative enzymatic capacity that relates to clinical outcomes. Muscle Nerve 53: 748–754, 2016
Fourth‐order energy‐preserving locally implicit time discretization for linear wave equations
Authors: Chabassier J. , Imperiale S.
Published: September 2015

A family of fourth‐order coupled implicit–explicit time schemes is presented as a special case of fourth‐order coupled implicit schemes for linear wave equations. The domain of interest is decomposed into several regions where different fourth‐order time discretizations are used, chosen among a family of implicit or explicit fourth‐order schemes. The coupling is based on a Lagrangian formulation on the boundaries between the several non‐conforming meshes of the regions. A global discrete energy is shown to be preserved and leads to global fourth‐order consistency in time. Numerical results in 1D and 2D for the acoustic and elastodynamics equations illustrate the good behavior of the schemes and their potential for the simulation of realistic highly heterogeneous media or strongly refined geometries, for which using everywhere an explicit scheme can be extremely penalizing. Accuracy up to fourth order reduces the numerical dispersion inherent to implicit methods used with a large time step and makes this family of schemes attractive compared with second‐order accurate methods. Copyright © 2015 John Wiley & Sons, Ltd.
Fabrication of patient specific composite orbital floor implants by stereolithography
Authors: Geven Mike A. , Varjas Viktor , Kamer Lukas , Wang Xinjiang , Peng Jiang , Eglin David , Grijpma Dirk W.
Published: September 2015

Fractures of the orbital floor are common in traffic accidents and assaults, and inadequate treatment can result in serious complications. Accurate anatomical reconstruction of the orbit using implants is the preferred treatment. Implants require degradability, adequate mechanical properties to support the orbital contents, and osteoinductivity or osteoconductivity so that the implant is replaced by de novo bone over time. Here, we report on a semi‐automatic process for the generation of virtual models of patient‐specific implants for orbital floor reconstruction. These models were generated using clinical computed tomography images of five clinical cases of orbital fracture. To fabricate accurately shaped implants based on the models, we utilized stereolithography, a high‐resolution additive manufacturing technique. We prepared resins from bioresorbable, photo‐curable functionalized poly(trimethylene carbonate) oligomers and osteoinductive nano‐hydroxyapatite to manufacture composite implants. Incorporation of 40 wt.% nano‐hydroxyapatite into photo‐crosslinked poly(trimethylene carbonate) leads to an increase of the E modulus, ultimate strength and toughness from 2.8 to 60 MPa, 2.4 to 7.1 N/mm2 and 330 to 1671 N/mm2, respectively. Additionally, water uptake increased from 0.8% to 7.3%, and water contact angle decreased from 80° to 68°. Patient‐specific, homogeneous, and mechanically stable implants can readily be prepared using these composite resins. Copyright © 2015 John Wiley & Sons, Ltd.
Effects of simulated microgravity on the expression of presynaptic proteins distorting the GABA/glutamate equilibrium – A proteomics approach
Authors: Wang Yun , Iqbal Javed , Liu Yahui , Su Rui , Lu Song , Peng Guang , Zhang Yongqian , Qing Hong , Deng Yulin
Published: September 2015

Microgravity may cause cognition‐related changes in the animal nervous system due to the resulting uneven flow of fluids in the body. These changes may restrict the long‐term stay of humans in space for various purposes. In this study, a rat tail suspension model (30o) was used to explore the effects of 21 days of prolonged simulated microgravity (SM) on the expression of proteins involved in cognitive functions in the rat hippocampus. SM decreased the content of γ‐aminobutyric acid (GABA) and increased the content of glutamate (Glu) in the rat hippocampus. A comparative 18O‐labeled quantitative proteomics strategy was applied to detect the differential expression of synaptic proteins under SM. Fifty‐three proteins were found to be differentially expressed under SM. Microgravity induces difficulty in the formation of the SNARE complex due to the down‐regulation of vesicle‐associated membrane protein 3(VAMP3) and syntaxin‐1A. Synaptic vesicle recycling may also be affected due to the dysregulation of syntaxin‐binding protein 5 (tomosyn), rab3A and its effector rim2. Both processes are disturbed, indicating that presynaptic proteins mediate a GABA/Glu imbalance under SM. These findings provide clues for understanding the mechanism of the GABA/Glu equilibrium in the hippocampus induced by microgravity in space and represent steps toward safe space travel.
Charge‐transfer complex formations of tetracyanoquinone (cyanil) and aromatic electron donors
Authors: Jalilov Almaz S. , Lu Jianjiang , Kochi Jay K.
Published: September 2015

Single‐electron oxidants are the primary reagents for investigations of the new oxidants and the development of electron‐accepting materials for application in optoelectronics. Quinones are the well‐known class of the neutral single‐electron oxidants. Here, we present the properties of the strongest neutral electron acceptor of this class tetracyanoquinone (cyanil) and investigate its electron‐accepting strength by analyzing the charge‐transfer complex formations with the aromatic donor molecules. Charge‐transfer complexes of tetracyanoquinone with aromatic electron donors are characterized spectroscopically in solution and isolated as the single crystals. Copyright © 2015 John Wiley & Sons, Ltd.
Emotional responses to the experience of cancer ‘alarm’ symptoms
Authors: Whitaker K. L. , Cromme S. , Winstanley K. , Renzi C. , Wardle J.
Published: September 2015

Objective

To qualitatively explore associations between emotional responses to experience of cancer ‘alarm’ symptoms and help‐seeking in a community sample of adults.

Method

Interviewees (n = 62) were recruited from a community sample (n = 2042) of adults aged ≥50 years, who had completed a health survey that included a list of cancer alarm symptoms. Participants who had reported an alarm symptom both at baseline and 3‐month follow‐up (n = 271), and who had consented to contact (n = 215), constituted the pool for invitations to interview.

Results

Over a third of participants (37%) described an emotional response to their symptom experience. In all these cases, there was evidence of awareness of the risk of cancer. Emotional responses were usually either classified as mild (‘worry’) or severe (‘fear’). Worry was often described in the context of a desire to seek medical help, either to rule out cancer or to minimise patient delay. In contrast, the ‘fear’ group described associations with death, the perceived incurability of cancer, and the consequence of a cancer diagnosis. Where the emotional reaction was fear, medical contact was seen as something to be avoided either because it had no value or because it was preferable not to be told a diagnosis.

Conclusion

In this community sample, worry about the possibility of cancer was associated with help‐seeking, either for reassurance or as part of a ‘sensible’ strategy to deal with the risk. In contrast, fear was associated with avoiding help‐seeking or even thinking about cancer, which could lead to prolonged help‐seeking intervals. © 2015 The Authors. Psycho‐Oncology published by John Wiley & Sons Ltd.
Investigation of the HIV‐1 matrix interactome during virus replication
Authors: Li Yan , Frederick Kristin M. , Haverland Nicole A. , Ciborowski Pawel , Belshan Michael
Published: September 2015

Purpose

Like all viruses, human immunodeficiency virus type 1 (HIV‐1) requires host cellular factors for productive replication. Identification of these factors may lead to the development of novel cell‐based inhibitors.

Experimental design

A Strep‐tag was inserted into the C‐terminus of the matrix (MA) region of the HIV‐1 gag gene. The resultant virus was replication competent and used to infect Jurkat T‐cells. MA complexes were affinity purified with Strep‐Tactin agarose. Protein quantification was performed using sequential window acquisition of all theoretical fragment ion spectra (SWATH) MS, data were log2‐transformed, and Student t‐tests with Bonferroni correction used to determine statistical significance. Several candidate proteins were validated by immunoblot and investigated for their role in virus infection by siRNA knockdown assays.

Results

A total of 17 proteins were found to be statistically different between the infected versus uninfected and untagged control samples. X‐ray repair cross‐complementing protein 6 (Ku70), X‐ray repair cross‐complementing protein 5 (Ku80), and Y‐box binding protein 1 (YB‐1) were confirmed to interact with MA by immunoblot. Knockdown of two candidates, EZRIN and Y‐box binding protein 1, enhanced HIV infection in vitro.

Conclusions and clinical relevance

The Strep‐tag allowed for the capture of viral protein complexes in the context of virus replication. Several previously described factors were identified and at least two candidate proteins were found to play a role in HIV‐1 infection. These data further increase our understanding of HIV host –cell interactions.
Prediction of the substrate for nonribosomal peptide synthetase (NRPS) adenylation domains by virtual screening
Authors: Lee T. Verne , Johnson Richard D. , Arcus Vickery L. , Lott J. Shaun
Published: September 2015

Nonribosomal peptide synthetases (NRPSs) synthesize a diverse array of bioactive small peptides, many of which are used in medicine. There is considerable interest in predicting NRPS substrate specificity in order to facilitate investigation of the many “cryptic” NRPS genes that have not been linked to any known product. However, the current sequence similarity‐based methods are unable to produce reliable predictions when there is a lack of prior specificity data, which is a particular problem for fungal NRPSs. We conducted virtual screening on the specificity‐determining domain of NRPSs, the adenylation domain, and found that virtual screening using experimentally determined structures results in good enrichment of the cognate substrate. Our results indicate that the conformation of the adenylation domain and in particular the conformation of a key conserved aromatic residue is important in determining the success of the virtual screening. When homology models of NRPS adenylation domains of known specificity, rather than experimentally determined structures, were built and used for virtual screening, good enrichment of the cognate substrate was also achieved in many cases. However, the accuracy of the models was key to the reliability of the predictions and there was a large variation in the results when different models of the same domain were used. This virtual screening approach is promising and is able to produce enrichment of the cognate substrates in many cases, but improvements in building and assessing homology models are required before the approach can be reliably applied to these models. Proteins 2015; 83:2052–2066. © 2015 Wiley Periodicals, Inc.
Mechanisms of Vasorelaxation Induced by Hexahydrocurcuminin Isolated Rat Thoracic Aorta
Authors: Moohammadaree Aida , Changtam Chatchawan , Wicha Piyawadee , Suksamrarn Apichart , Tocharus Jiraporn , Tocharus Chainarong
Published: September 2015

This study was designed to examine the vasorelaxant effects of hexahydrocurcumin (HHC), one of the major natural metabolites of curcumin from Curcuma longa, on rat isolated aortic rings, and the underlying mechanisms. Isometric tension of the aortic rings was recorded using organ bath system. HHC (1 nM to 1 mM) relaxed the endothelium‐intact aortic rings pre‐contracted with PE and KCl in a concentration‐dependent manner. Removal of the endothelium did not alter the effect of HHC‐induced relaxation. In Ca2+‐free Krebs solution, HHC significantly inhibited the CaCl2‐induced contraction in high K+ depolarized rings and suppressed the transient contraction induced by PE and caffeine in a concentration‐dependent manner. HHC was also observed to relax phobal‐12‐myristate‐13‐acetate (PMA), an activator of protein kinase C (PKC), precontracted aortic rings in a concentration‐dependent manner with EC50 values equivalent to 93.36 ± 1.03 μM. In addition, pre‐incubation with propranolol (a β‐adrenergic receptor blocker) significantly attenuated the HHC‐induced vasorelaxation. These results suggest that the vasorelaxant effect of HHC is mediated by the endothelium‐independent pathway, probably because of the inhibition of extracellular Ca2+ influx through voltage‐operated Ca2+ channels and receptor‐operated Ca2+ channels, the inhibition of Ca2+mobilization from intracellular stores, as well as inhibition of PKC‐mediated Ca2+‐independent contraction. Moreover, HHC produces vasorelaxant effects probably by stimulating the β‐adrenergic receptor. Copyright © 2015 John Wiley & Sons, Ltd.
Structural and nanomechanical properties of sol–gel prepared (K, Na)NbO3 thin films
Authors: Bruncková Helena , Medvecký Ľubomír , Hvizdoš Pavol , Ďurišin Juraj
Published: September 2015

Perovskite (K, Na)NbO3 (KNN) thin films (~100 nm) were prepared by sol–gel/spin coating process on Pt/SiO2/Si substrates and annealed at 650 °C. The structural properties of KNN films were confirmed by X‐ray diffraction analysis (XRD), Raman spectroscopy and scanning electron, transmission electron and atomic force microscopy (SEM, TEM and AFM) analysis. Pure perovskite phase of K0.65Na0.35NbO3 in nonstoichiometric composition with monoclinic symmetry in film was revealed. Uniform homogeneous microstructure of KNN film with the roughness (~6.9 nm) contained spherical particles (~50–90 nm). Nanoindentation technique was used to characterize the mechanical properties of KNN films. Elastic modulus and hardness of Pt, SiO2 and KNN thin films were calculated from their composite values of KNN/Pt/SiO2/Si film/substrate system. The modulus and hardness of KNN film (71 and 4.5 GPa) were lower in comparison with SiO2 (100 and 7.5 GPa). Pt film (~30 nm) did not influence the composite modulus, but had effect on hardness of KNN film. Copyright © 2015 John Wiley & Sons, Ltd.
A simple calibration procedure of polycapillary based portable micro‐XRF spectrometers for reliable quantitative analysis of cultural heritage materials
Authors: Kantarelou V. , Karydas A. G.
Published: September 2015

Portable micro‐X‐ray fluorescence (micro‐XRF) spectrometers mostly utilize a polycapillary X‐ray lens along the excitation channel to collect, propagate and focus down to few tens of micrometers the X‐ray tube radiation. However, the polycapillary X‐ray lens increases the complexity of the quantification of micro‐XRF data because its transmission efficiency is strongly dependent on the lens specifications and the propagated X‐ray energy. This feature results to a significant and not easily predicted modification of the energy distribution of the primary X‐ray tube spectrum. In the present work, we propose a simple calibration procedure of the X‐ray lens transmission efficiency based on the fundamental parameters approach in XRF analysis. This analytical methodology is best suited for compact commercial and portable micro‐XRF spectrometers. The developed calibration procedure is validated through the quantitative analysis of a broad range of samples with archeological relevance such as glasses, historical copper alloys, silver and gold alloys offering an overall accuracy of less than 10%–15%. Copyright © 2015 John Wiley & Sons, Ltd.