bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of Cu(II)‐loaded brushite scaffolds on growth and activity of osteoblastic cells
Authors: Ewald Andrea , Käppel Christine , Vorndran Elke , Moseke Claus , Gelinsky Michael , Gbureck Uwe
Published: April 2012

Bone substitute materials such as calcium phosphate cements (CPC) are frequently used as growth factor carriers for the stimulation of osteoblast‐formation around an implant. However, biological modification based on delicate protein factors like extracellular matrix proteins or growth factors is subject to a number of shortcomings like the need for storage below room temperature and cost of production. The aim of this study was to investigate ionic modification as an alternative bioinorganic route for implant modification. Although it is known that Cu(II) plays a role in angiogenesis and bone formation, not all involved processes are well understood yet. In this study the in vitro effect of Cu(II) on growth and activity of osteoblastic cells seeded on brushite (CaHPO4 · 2 H2O) scaffolds as well as on glass discs was investigated. The results show that Cu(II) enhances cell activity and proliferation of osteoblastic cells on CPC and furthermore affects the expression of several bone specific proteins such as bone sialo protein or osteocalcin. Therefore, the modification of CPC with Cu(II) may offer a promising alternative to protein based modification to stimulate cellular activity for an improved bone healing. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A: 2392–2400, 2012.
Empirical van der Waals corrections to solid‐state density functional theory: Iodine and phosphorous containing molecular crystals
Authors: Kendrick John , Leusen Frank J. J. , Neumann Marcus A.
Published: April 2012

Parameters are derived for a molecular mechanics type dispersive correction to solid‐state density functional theory calculations on molecular crystals containing iodine and phosphorous. The molecular C6 coefficients are derived from photoabsorption differential oscillator strength spectra determined from accurate (e,e) dipole spectra. The cross‐over parameters, which ensure correct behavior at short internuclear distances, are obtained by fitting predicted crystal lattice parameters to experimental data. The accuracy of the parameterization is assessed by optimizing the experimental structures of several additional phosphorous and iodine containing molecular crystals and by examining the relative stabilities of the known polymorphs of phosphorous pentoxide and the stabilities of different packings of an iodine containing molecular crystal, 2,9‐bis(iodo)anthanthrone, which has been the subject of a crystal structure prediction study. Optimizations of the experimental crystal structures did not lead to significant geometric deviations. The optimized experimental structure of 2,9‐bis(iodo)anthanthrone is the lowest energy packing found, indicating a satisfactory description of both energy and structure for these molecular crystals. © 2012 Wiley Periodicals, Inc.
Uterine Epithelial Morphology and Progesterone Receptors in a Mifepristone‐treated Viviparous Lizard Pseudemoia entrecasteauxii (Squamata: Scincidae) During Gestation
Authors: BIAZIK JOANNA M. , PARKER SCOTT L. , MURPHY CHRISTOPHER R. , THOMPSON MICHAEL B.
Published: April 2012

Structural and functional changes to the uterus associated with maintenance of pregnancy are controlled primarily by steroid hormones such as progesterone. We tested the hypothesis that progesterone regulates uterine structural changes during pregnancy in the viviparous skink, Pseudemoia entrecasteauxii, by treating pregnant females with the progesterone receptor antagonist mifepristone at different stages of pregnancy. Expression and distribution of progesterone receptor was determined using Western blot and immunohistochemistry. During early pregnancy, mifepristone treatment resulted in altered uterine epithelial cell surface morphology and high embryo mortality, but did not affect females at mid and late stages of pregnancy. Females treated with mifepristone in early pregnancy exhibited abnormal uterine epithelial cell morphology such as lateral blebbing and presence of wide gaps between cells indicating loss of intercellular attachment. Chorioallantoic membranes of the embryo were not affected by mifepristone treatment. Two isoforms (55 kDa and 100 kDa) of progesterone receptor were identified using immunoblots and both isoforms were localized to the nucleus of uterine epithelial cells. The 55 kDa isoform was expressed throughout pregnancy, whereas the 100 kDa isoform was expressed during mid and especially late pregnancy. In P. entrecasteauxii, mifepristone may prevent successful embryo attachment in early pregnancy through its effects on uterine epithelial cells but may have little effect on pregnancy once the maternal‐embryo structural relationship is established. J. Exp. Zool. (Mol. Dev. Evol.) 318:148–158, 2012. © 2012 Wiley Periodicals, Inc.
Dynamic expression of Pax6 in the shark olfactory system: evidence for the presence of Pax6 cells along the olfactory nerve pathway
Authors: Ferreiro‐Galve Susana , Candal Eva , Rodríguez‐Moldes Isabel
Published: April 2012

Pax6 is involved in the control of neuronal specification, migration, and differentiation in the olfactory epithelium and in the generation of different interneuron subtypes in the olfactory bulb. Whether these roles are conserved during evolution is not known. Cartilaginous fish are extremely useful models for assessing the ancestral condition of brain organization because of their phylogenetic position. To shed light on the evolution of development of the olfactory system in vertebrates and on the involvement of Pax6 in this process, we analyzed by in situ hybridization and immunohistochemistry the expression pattern of Pax6 in the developing olfactory system in a basal vertebrate, the lesser spotted dogfish Scyliorhinus canicula. This small shark is becoming an important fish model in studies of vertebrate development. We report Pax6 expression in cells of the olfactory epithelium and olfactory bulb, and present the first evidence in vertebrates of strings of Pax6‐expressing cells extending along the developing olfactory nerve. The results indicate the olfactory epithelium as the origin of these cells. These data are compatible with a role for Pax6 in the development of the olfactory epithelium and fibers, and provide a basis for future investigations into the mechanisms that regulate development of the olfactory system throughout evolution. J. Exp. Zool. (Mol. Dev. Evol.) 318:79–90, 2012. © 2011 Wiley Periodicals, Inc.
Structural, morphological and nanomechanical characterisation of intermediate states in the ageing of erythrocytes
Authors: Girasole M. , Dinarelli S. , Boumis G.
Published: April 2012

The study of the mechanical properties of biosystems and the relationship with their biochemical and structural functionality is an increasingly interesting subject of investigation. In recent years, in particular, the use of the atomic force microscopy provides the tools for understanding the molecular basis of the mechanical behaviour of the biosystems. The ageing of erythrocytes [red blood cells (RBCs)] constitutes a particularly interesting subject of study because of its fundamental role in triggering the cell turnover by promoting the removal of malfunctioning RBCs when specific ageing markers appear on their surface. Moreover, it is also interesting to study the role that the variation in the cells mechanical properties plays in the progress of the phenomenon. In this study, the ageing of RBCs, accelerated by depleting the cells of their ATP, has been investigated by two methods. The first is a recently developed nondestructive approach that correlates the roughness of the plasma membrane to the mechanical characteristics and the structural integrity of the cell membrane‐skeleton. The second consists in directly measuring the nanomechanical properties by acquiring and analysing force curves on the cell membrane. The application of the two methods allowed to define, for the first time, the general scheme of alterations the cells experience during the ageing. In particular, a progressive decrease of the membrane roughness, correlated to a weakening of the membrane‐skeleton support, and a complex pattern of changes in the nanomechanical properties, which drives the morphological variation and the occurrence of the specific ageing markers on the cells, have been revealed. Copyright © 2012 John Wiley & Sons, Ltd.
Force volume and stiffness tomography investigation on the dynamics of stiff material under bacterial membranes
Authors: Longo Giovanni , Rio Laura Marques , Roduit Charles , Trampuz Andrej , Bizzini Alain , Dietler Giovanni , Kasas Sandor
Published: April 2012

The determination of the characteristics of micro‐organisms in clinical specimens is essential for the rapid diagnosis and treatment of infections. A thorough investigation of the nanoscale properties of bacteria can prove to be a fundamental tool. Indeed, in the latest years, the importance of high resolution analysis of the properties of microbial cell surfaces has been increasingly recognized. Among the techniques available to observe at high resolution specific properties of microscopic samples, the Atomic Force Microscope (AFM) is the most widely used instrument capable to perform morphological and mechanical characterizations of living biological systems. Indeed, AFM can routinely study single cells in physiological conditions and can determine their mechanical properties with a nanometric resolution. Such analyses, coupled with high resolution investigation of their morphological properties, are increasingly used to characterize the state of single cells.

In this work, we exploit the capabilities and peculiarities of AFM to analyze the mechanical properties of Escherichia coli in order to evidence with a high spatial resolution the mechanical properties of its structure. In particular, we will show that the bacterial membrane is not mechanically uniform, but contains stiffer areas. The force volume investigations presented in this work evidence for the first time the presence and dynamics of such structures. Such information is also coupled with a novel stiffness tomography technique, suggesting the presence of stiffer structures present underneath the membrane layer that could be associated with bacterial nucleoids. Copyright © 2012 John Wiley & Sons, Ltd.
Atomic force microscopy characterization of silver nanoparticles interactions with marine diatom cells and extracellular polymeric substance
Authors: Pletikapić Galja , Žutić Vera , Vinković Vrček Ivana , Svetličić Vesna
Published: April 2012

This study highlights the capacity of atomic force microscopy (AFM) for investigating nanoparticle (NP) algal cell interaction with a subnanometer resolution. We designed a set of AFM experiments to characterize NP size, shape, and structure to visualize changes in the cell morphology induced by NPs and to characterize NP interaction with the extracellular polymeric substance (EPS). Samples for AFM imaging were prepared using the same protocol—drop deposition on mica and imaged in air. Here we address the interactions of Ag NPs with ubiquitous, lightly silicified marine diatoms Cylindrotheca fusiformis and Cylindrotheca closterium and their EPS. In natural seawater used throughout this study, the single Ag NPs adopted truncated tetrahedron morphology with particle heights of 10, 20, 30, and 40 nm. This size class Ag NPs penetrates the cell wall through the valve region built of silica NPs embedded in organic matrix. The Ag NPs cause a local damage inside the cell without disintegration of the cell wall. The EPS production has been shown to increase as a feedback response to Ag NP exposure and may contribute to detoxification mechanisms. Imaging EPS at high resolution revealed the incorporation of Ag NPs and their aggregates into the EPS–gel matrix, proving their detoxifying capacity. Copyright © 2012 John Wiley & Sons, Ltd.
Optically detected magnetic resonance studies of luminescence‐quenching processes in π‐conjugated materials and organic light‐emitting devices
Authors: Shinar J.
Published: April 2012

It is widely recognized that nonradiative quenching of excitons by other excitons and polarons become the dominant decay mechanism of these excitons at high excitation densities. These quenching processes cause the roll‐off in the efficiency of organic light‐emitting devices (OLEDs) and prevent lasing at high injection current densities. This review presents the optically‐detected magnetic resonance (ODMR) evidence for these photoluminescence‐ and electroluminescence‐quenching processes. And while it provides such evidence for quenching of singlet excitons by polarons and triplet excitons, it reveals the central role of the strongly spin‐dependent annihilation of triplet excitons by polarons, since under normal excitation conditions the steady‐state polaron and triplet exciton populations are 100–104 times the singlet exciton population. In addition, it also suggests that quenching of singlet excitons by bipolarons, likely stabilized by a counterpolaron or countercharge at specific sites, may also be a significant quenching mechanism that also affects the charge transport properties.
Prophylaxis versus preemptive therapy for cytomegalovirus disease in high-risk liver transplant recipients
Authors: Bodro Marta , Sabé Núria , Lladó Laura , Baliellas Carme , Niubó Jordi , Castellote Jose , Fabregat Joan , Rafecas Antoni , Carratalà Jordi
Published: April 2012

Cytomegalovirus (CMV) infection is an opportunistic infection frequently found after solid organ transplantation, and it contributes significantly to mortality and morbidity. CMV-seronegative recipients of grafts from CMV-seropositive donors have the highest risk of CMV disease. The most appropriate strategy for preventing CMV disease in this population is a matter of active debate. In this study, we compared prophylaxis and preemptive therapy for the prevention of CMV disease in donor-seropositive/recipient-seronegative (D+/R−) liver recipients. To this end, we selected a retrospective cohort of liver recipients (1992-2009) for analysis. D+/R− patients were identified from the liver transplant program database. Eighty of 878 consecutive liver recipients (9%) were D+/R−. Six of these patients died within 30 days of transplantation and were excluded. Thirty-five of the remaining D+/R− patients (47%) received prophylaxis, and 39 patients (53%) followed a preemptive strategy based on CMV antigenemia surveillance. Fifty-four (73%) were men, the median age was 49 years (range = 15-68 years), and the mean follow-up was 68 months (range = 8-214 months). The baseline characteristics and the initial immunosuppressive regimens were similar for the 2 groups. Ganciclovir or valganciclovir was the antiviral drug used initially in both strategy groups. CMV disease occurred more frequently among D+/R− liver recipients receiving preemptive therapy (33.3% versus 8.6% for the prophylaxis group, P = 0.01), whereas late-onset CMV disease was found only in patients receiving prophylaxis (5.7% versus 0% for the preemptive therapy group, P = 0.22). No significant differences in acute allograft rejection, other opportunistic infections, or case fatality rates were observed. According to our data, prophylaxis was more effective than preemptive therapy in preventing CMV disease in high-risk liver transplant recipients. Liver Transpl, 2012. © 2012 AASLD.
Co(acac)2‐Mediated Radical Polymerization of Acrylonitrile: Control Over Molecular Weights and Copolymerization With Methyl Methacrylate
Authors: Buchmeiser Michael R. , Marino Michael G.
Published: April 2012

The cobalt‐mediated radical polymerization of acrylonitrile in DMSO using cobalt (II) acetylacetonate [Co(acac)2] as mediator is studied. Both the evolution of molecular weight and conversion over time under various conditions are monitored. Molecular weights increase sharply at the beginning of the reaction and subsequently grow linearly with conversion. No branching of the polymer is observed by 13C NMR. By a careful design of the reaction parameters, number‐average molecular weights >1.2 · 105 g · mol−1 with a PDI around 2.4 together with conversions of up to 90% within 24 h are achieved. The copolymerization parameters of acrylonitrile with methyl methacrylate in DMSO at 30 °C are determined using the Kelen‐Tüdõs approach giving rAN = 0.33, rMMA = 0.71.

magnified image
Transforming Frozen Self‐Assemblies of Amphiphilic Block Copolymers Into Dynamic pH‐Sensitive Micelles
Authors: Dutertre Fabien , Boyron Olivier , Charleux Bernadette , Chassenieux Christophe , Colombani Olivier
Published: April 2012

The self‐assembly in water of an amphiphilic P(nBMA50%‐stat‐DMAEMA50%)100‐b‐PDMAEMA235 diblock copolymer based on hydrophilic dimethylaminoethylmethacrylate (DMAEMA) units and hydrophobic n‐butylmethacrylate (nBMA) ones is reported. DMAEMA units have been incorporated into the hydrophobic block of this copolymer to moderate its hydrophobic character. Light scattering experiments revealed the formation of micelles whose apparent aggregation number varied reversibly with the ionization degree of the DMAEMA units. Incorporating hydrophilic units into the hydrophobic block of an amphiphilic block copolymer is thus a way to generate dynamic aggregates in aqueous medium. As this strategy was also successful using other types of hydrophilic units, we believe it to be universal.
Selective COSY‐J‐resolved‐HMBC, a new method for improving sensitivity of cross peaks of methine proton signals attached to a methyl group
Authors: Furihata Kazuo , Tashiro Mitsuru
Published: April 2012

Improved pulse sequences for measuring long‐range C‐H coupling constants (nJC‐H), named selective COSY‐J‐resolved HMBC‐1 and −2, have been developed. In the spin systems, such as ‐CHC‐CHA(CH3)‐CHB‐, a methine proton HA splits into a multiplet owing to several vicinal couplings with protons, resulting in attenuation of its cross‐peak intensity. Therefore, the measurements of nJC‐H with HA are generally difficult in the J‐resolved HMBC or selective J‐resolved HMBC spectrum. With the aim of accurate measurements of nJC‐H in such a spin system, we have developed new pulse sequences, which transfer the magnetization of a methyl group to its adjacent methine proton. The proposed pulse sequences successfully enable to enhance the sensitivity of HA cross peak in comparison with the selective J‐resolved HMBC pulse sequence. Copyright © 2012 John Wiley & Sons, Ltd.
Endoplasmic reticulum stress is involved in granulosa cell apoptosis during follicular atresia in goat ovaries
Authors: Lin Pengfei , Yang YanZhou , Li Xiao , Chen Fenglei , Cui ChenChen , Hu Linyong , Li Qian , Liu Wei , Jin YaPing
Published: April 2012

Follicular atresia is primarily induced by granulosa cell apoptosis, but description of the apoptotic pathway in granulosa cells is incomplete. In this study, we explored the possibility that endoplasmic reticulum (ER) stress could be involved in granulosa cell apoptosis during goat follicular atresia. Immunohistochemical analysis revealed that DNA damage‐inducible transcript 3 (DDIT3) and glucose‐regulated protein 78 (Grp78) were observed in scattered apoptotic granulosa cells of atretic follicles. Grp78 and DDIT3 mRNA and protein were upregulated in granulosa cells during follicular atresia, although DDIT3 was not significantly different between early atretic and progressed atretic follicles. Spontaneous apoptosis was also observed in vitro in granulosa cells induced by serum deprivation or by the ER stress agent tunicamycin, both inducing similar increases in DDIT3 mRNA. Activating transcription factor‐6 (ATF6) and ATF4 mRNAs were significantly increased during granulosa cell apoptosis in vivo; in contrast to ATF6, ATF4 mRNA was attenuated after 16 hr of culture despite the persistence of ER stress. Taken together, ER stress‐dependent DDIT3 pathways may play an important role in the regulation of selective granulosa cell apoptosis in goat ovaries during early follicular atresia. Serum deprivation could also increase apoptosis of cultured granulosa cells through the ER stress pathway as both ATF6 and PERK/eIF2α/ATF4 signaling have been implicated in the granulosa cell apoptosis of atretic follicles. Mol. Reprod. Dev. 79:423–432, 2012. © 2012 Wiley Periodicals, Inc.
Perfusion phantom: An efficient and reproducible method to simulate myocardial first‐pass perfusion measurements with cardiovascular magnetic resonance
Authors: Chiribiri Amedeo , Schuster Andreas , Ishida Masaki , Hautvast Gilion , Zarinabad Niloufar , Morton Geraint , Otton James , Plein Sven , Breeuwer Marcel , Batchelor Philip , Schaeffter Tobias , Nagel Eike
Published: April 2012

The aim of this article is to describe a novel hardware perfusion phantom that simulates myocardial first‐pass perfusion allowing comparisons between different MR techniques and validation of the results against a true gold standard. MR perfusion images were acquired at different myocardial perfusion rates and variable doses of gadolinium and cardiac output. The system proved to be sensitive to controlled variations of myocardial perfusion rate, contrast agent dose, and cardiac output. It produced distinct signal intensity curves for perfusion rates ranging from 1 to 10 mL/mL/min. Quantification of myocardial blood flow by signal deconvolution techniques provided accurate measurements of perfusion. The phantom also proved to be very reproducible between different sessions and different operators. This novel hardware perfusion phantom system allows reliable, reproducible, and efficient simulation of myocardial first‐pass MR perfusion. Direct comparison between the results of image‐based quantification and reference values of flow and myocardial perfusion will allow development and validation of accurate quantification methods. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
Reducing localized signal fluctuation in fMRI using spectral–spatial fat saturation
Authors: Xu Dan , Hinks R. Scott , King Kevin F.
Published: April 2012

Conventional 1D, spatially nonselective fat saturation can generate uncrushed fat signals in areas far outside the imaging slice where crushers are weak because of reduced gradient linearity. These fat signals can corrupt in‐slice water signal, and in functional MRI, they can manifest themselves as artifacts such as clouds in image background or localized signal fluctuation over time. In this article, a spectral–spatial radiofrequency pulse is proposed to replace the conventional, spatially nonselective fat saturation pulse. The advantage of the proposed method is that fat protons far outside the image slice would not be excited because of the spatial selectivity, thereby removing the root cause of the fat aliasing artifacts. The proposed method also preserves thin slice capability, pulse duration, and fat suppression performance of the conventional method. Bloch simulation and human volunteer results show that the method is effective in reducing the fat aliasing artifacts seen in functional MRI. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.
A more detailed mechanism to explain the “bands of Fontana” in peripheral nerves
Authors: Merolli Antonio , Mingarelli Luigi , Rocchi Lorenzo
Published: April 2012

Introduction:

In 1779, Fontana identified transverse and oblique bands along peripheral nerves. Subsequent studies pointed alternatively to endoneural or perineural components as the cause. Our aim was to clarify these conflicting findings.

Methods:

Recoiling of the bands of Fontana was video‐recorded in the rat sciatic nerve. Computer‐assisted design (CAD) software was used to model the nerve by interference figures.

Results:

In vivo microdissection showed distinctive, black‐and‐white, closely packed bands in the perineurium, which differed from the widely spaced, translucent, dark/pale gray, staggered bands in the endoneurium. CAD merging of these 2 patterns produced images resembling the bands observed in vivo.

Conclusions:

Two repetitive structures with different characteristics, 1 in the perineurium and the other in the endoneurium, merge to give the appearance of these bands. Muscle Nerve 46: 540–547, 2012
Asparaginase‐associated myelosuppression and effects on dosing of other chemotherapeutic agents in childhood acute lymphoblastic leukemia
Authors: Merryman Reid , Stevenson Kristen E. , Gostic William J. , Neuberg Donna , O'Brien Jane , Sallan Stephen E. , Silverman Lewis B.
Published: April 2012

Although L‐asparaginase (ASP) is associated with several toxicities, its myelosuppressive effect has not been well characterized. On DFCI ALL Consortium Protocol 05‐01 for children with newly diagnosed acute lymphoblastic leukemia, the Consolidation phase and the initial portion of the Continuation phase were identical for standard risk patients, except ASP was given only during Consolidation. Comparing the two treatment phases revealed that low blood counts during Consolidation with ASP resulted in more dosage reductions of 6‐mercaptopurine and methotrexate. The myelosuppressive effect of ASP should be considered when designing treatment regimens to avoid excessive toxicity and dose reductions of other critical chemotherapy agents. Pediatr Blood Cancer 2012; 59: 925–927. © 2012 Wiley Periodicals, Inc.
Synthesis and biological evaluation of new active For‐Met‐Leu‐Phe‐OMe analogues containing para‐substituted Phe residues
Authors: Mollica Adriano , Feliciani Federica , Stefanucci Azzurra , Costante Roberto , Lucente Gino , Pinnen Francesco , Notaristefano Daniela , Spisani Susanna
Published: April 2012

In the present study, we report synthesis and biological evaluation of the N‐Boc‐protected tripeptides 4a–l and N‐For protected tripeptides 5a–l as new For‐Met‐Leu‐Phe‐OMe (fMLF‐OMe) analogues. All the new ligands are characterized by the C‐terminal Phe residue variously substituted at position 4 of the aromatic ring. The agonism of 5a–l and the antagonism of 4a–l (chemotaxis, superoxide anion production, lysozyme release as well as receptor binding affinity) have been examined on human neutrophils. No synthesized compounds has higher activity than the standard fMLF‐OMe tripeptide to stimulate chemotaxis, although compounds 5a and 5c with ‐CH3 and ‐C(CH3)3, respectively, in position 4 on the aromatic ring, are better than the standard tripeptide to stimulate the production of superoxide anion, in higher concentration. Compounds 4f and 4i, containing ‐F and ‐I in position 4, respectively, on the aromatic ring of phenylalanine, exhibit significant chemotactic antagonism. The influence of the different substitution at the position 4 on the aromatic ring of phenylalanine is discussed. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
Substrate‐Baited Nanoparticles: A Catch and Release Strategy for Enzyme Recognition and Harvesting
Authors: Daniele Michael A. , Bandera Yuriy P. , Sharma Deepti , Rungta Parul , Roeder Ryan , Sehorn Michael G. , Foulger Stephen H.
Published: April 2012

The isolation of a single type of protein from a complex mixture is vital for the characterization of the function, structure, and interactions of the protein of interest and is typically the most laborious aspect of the protein purification process. In this work, a model system is utilized to show the efficacy of synthesizing a “baited” nanoparticle to capture and recycle enzymes (proteins that catalyze chemical reactions) from crude cell lysate. Enzyme trapping and recycling is illustrated with the carbazole 1,9a‐dioxygenase (CARDO) system, an enzyme important in bioremediation and natural product synthesis. The enzymes are baited with azide‐modified carbazolyl moieties attached to poly(propargyl acrylate) nanoparticles through a click transformation. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) analysis indicates the single‐step procedure to immobilize the enzymes on the particles is capable of significantly concentrating the protein from raw lysate and sequestering all required components of the protein to maintain bioactivity. These results establish a universal model applicable to concentrating and extracting known substrate–protein pairs, but it can be an invaluable tool in recognizing unknown protein–ligand affinities.
Use of modified snares to estimate bobcat abundance
Authors: Stricker Heather K. , Belant Jerrold L. , Beyer Dean E. , Kanefsky Jeanette , Scribner Kim T. , Etter Dwayne R. , Fierke Jean
Published: April 2012

Although genetic and analytical methods for estimating wildlife abundance have improved rapidly over the last decade, effective methods for collecting hair samples from terrestrial carnivores in a mark–recapture framework have lagged. Hair samples are generally collected using methods that permit sampling of multiple individuals during a single sampling period that can cause genotyping errors due to cross‐contamination. We evaluated a modified body snare as a single‐sample method to obtain bobcat hair samples suitable for individual identification using DNA analyses to estimate population size. We used a systematic grid (2.5 × 2.5 km) overlaid on a 278.5 km2 study area in Michigan's Upper Peninsula to distribute sampling effort. In each of 44 grid cells, we placed 2–6 snares at established sampling stations and collected hair samples weekly for 8 weeks during January–March 2010. We collected 230 hair samples overall, with 91% of sampling stations obtaining at least 1 hair sample. Fifty‐seven percent of samples had sufficient DNA for species identification, which included bobcat (Lynx rufus, n = 17); raccoon (Procyon lotor, n = 62); coyote, dog, or wolf (Canis spp., n = 29); fox (Vulpes vulpes or Urocyon cinereoargenteus, n = 4); and fisher (Martes pennanti, n = 1). We identified 8 individual bobcats and using Huggins closed capture population models with a one‐half mean maximum distance moved buffer, estimated 10 individuals within the trapping area (95% confidence interval = 8–28) with a density of 3.0 bobcats/100 km2. Our method provides an effective, single‐sample technique for detecting bobcats and estimating abundance. © 2012 The Wildlife Society.
Recent Advancements in Medical Simulation: Patient‐Specific Virtual Reality Simulation
Authors: Willaert Willem I. M. , Aggarwal Rajesh , Van Herzeele Isabelle , Cheshire Nicholas J. , Vermassen Frank E.
Published: April 2012

Background

Patient‐specific virtual reality simulation (PSVR) is a new technological advancement that allows practice of upcoming real operations and complements the established role of VR simulation as a generic training tool. This review describes current developments in PSVR and draws parallels with other high‐stake industries, such as aviation, military, and sports.

Methods

A review of the literature was performed using PubMed and Internet search engines to retrieve data relevant to PSVR in medicine. All reports pertaining to PSVR were included. Reports on simulators that did not incorporate a haptic interface device were excluded from the review.

Results

Fifteen reports described 12 simulators that enabled PSVR. Medical procedures in the field of laparoscopy, vascular surgery, orthopedics, neurosurgery, and plastic surgery were included. In all cases, source data was two‐dimensional CT or MRI data. Face validity was most commonly reported. Only one (vascular) simulator had undergone face, content, and construct validity. Of the 12 simulators, 1 is commercialized and 11 are prototypes. Five simulators have been used in conjunction with real patient procedures.

Conclusions

PSVR is a promising technological advance within medicine. The majority of simulators are still in the prototype phase. As further developments unfold, the validity of PSVR will have to be examined much like generic VR simulation for training purposes. Nonetheless, similar to the aviation, military, and sport industries, operative performance and patient safety may be enhanced by the application of this novel technology.
Radiant Ignition of Polyurethane Foam: The Effect of Sample Size
Authors: Hadden Rory , Alkatib Abubakar , Rein Guillermo , Torero José L.
Published: April 2012

Although smouldering ignition of upholstery items remains a leading cause of residential fire deaths, relatively little research is conducted on the topic. An experimental investigation of the effect of sample size on the ignition and spread of smouldering and flaming in polyurethane foam under natural flow conditions is reported here. Polyurethane foam samples are used because this is a common material in modern, residential environments and one for which there exists significant quantities of previous experimental data in the literature. Samples of different square cross-section size and a fixed height of 150 mm are insulated on all sides except the top which is exposed to a radiant heat flux and is open to the air. Samples with side lengths of 50 mm, 100 mm, and 140 mm are studied. Ignition and spread dynamics are diagnosed using thirteen thermocouples located along the vertical centre line. The onset of smouldering ignition (13 
$$\hbox{kW}\, \hbox{m}^{-2}$$
, 8 
$$\hbox{kW}\, \hbox{m}^{-2}$$
and
$$7\,\hbox{kW}\, \hbox{m}^{-2}$$
for 50 mm, 100 mm and 140 mm sample sizes respectively) is observed at significantly lower heat fluxes that flaming (45 
$$\hbox{kW}\,\hbox{m}^{-2}$$
, 32 
$$\hbox{kW}\,\hbox{m}^{-2}$$
and
$$30\,\hbox{kW}\,\hbox{m}^{-2}$$
respectively). Critical heat fluxes for smouldering and flaming ignition increase with decreasing sample size, with smouldering ignition being significantly more sensitive to sample size than flaming ignition under the size range studied. Smouldering spread rates are measured in the range from 3 
$$\hbox{mm}\, \hbox{min}^{-1}$$
to
$$25\,\hbox{mm}\, \hbox{min}^{-1}$$
and found to be a strong function of the heat flux and depth of the smoulder front. The effect of sample size on smouldering has been theoretically proposed before but this is the first time that this effect has been demonstrated experimentally for ignition. The fact that large samples result in the lowest critical heat flux could have implications for testing procedures and translation of results from small-scale testing to real-scale in the built environment.
Human Nature and the Transcendent
Authors: Cottingham John
Published: April 2012

Let me start with the enigmatic dictum of Blaise Pascal:‘l'homme passe l'homme’ –‘man goes beyond himself’; ‘humanity transcends itself’. What does this mean? On one plausible interpretation, Pascal is adverting to that strangerestlessnessof the human spirit which so many philosophers have pondered on, from Augustine before him, to Kierkegaard and many subsequent writers since. To be human is to recognize that we are, in a certain sense, incomplete beings. We are on a journey to a horizon that always seems to recede from view. Unlike all the other animals, who need nothing further for their thriving and flourishing once the appropriate environmental conditions are provided, human beings, even when all their needs are catered for – physical, biological, social, cultural – and even when they enjoy a maximally secure and enriching environment, still have a certain resistance to resting content with existence defined within a given set of parameters. They still have the restless drive to reach forward to something more.
On parameterization of the inverse problem for estimating aquifer properties using tracer data
Authors: Kowalsky M. B. , Finsterle S. , Williams K. H. , Murray C. , Commer M. , Newcomer D. , Englert A. , Steefel C. I. , Hubbard S. S.
Published: April 2012

In developing a reliable approach for inferring hydrological properties through inverse modeling of tracer data, decisions made on how to parameterize heterogeneity (i.e., how to represent a heterogeneous distribution using a limited number of parameters that are amenable to estimation) are of paramount importance, as errors in the model structure are partly compensated for by estimating biased property values during the inversion. These biased estimates, while potentially providing an improved fit to the calibration data, may lead to wrong interpretations and conclusions and reduce the ability of the model to make reliable predictions. We consider the estimation of spatial variations in permeability and several other parameters through inverse modeling of tracer data, specifically synthetic and actual field data associated with the 2007 Winchester experiment from the Department of Energy Rifle site. Characterization is challenging due to the real‐world complexities associated with field experiments in such a dynamic groundwater system. Our aim is to highlight and quantify the impact on inversion results of various decisions related to parameterization, such as the positioning of pilot points in a geostatistical parameterization; the handling of up‐gradient regions; the inclusion of zonal information derived from geophysical data or core logs; extension from 2‐D to 3‐D; assumptions regarding the gradient direction, porosity, and the semivariogram function; and deteriorating experimental conditions. This work adds to the relatively limited number of studies that offer guidance on the use of pilot points in complex real‐world experiments involving tracer data (as opposed to hydraulic head data).
On the risk of obtaining misleading results by pooling streamflow data for trend analyses
Authors: Viviroli D. , Schädler B. , Schmocker‐Fackel P. , Weiler M. , Seibert J.
Published: April 2012

Floods have broad impacts on nature, society, and the economy. The frequency and intensity of flood events are generally believed to increase with the anticipated changes in temperature and precipitation. Trend analyses are important tools to quantify these changes, but often, they provide inconclusive results, partly because of the limited data availability. One way to overcome this limitation is to pool data from different gauging stations. However, pooling data from different stations may lead to misleading results. For example, using pooled flood data Allamano et al. (2009a) found a considerable increase of flooding risks for Switzerland. Here we demonstrate that the previous finding of increased flooding risks was an artifact of the pooling of stations and the fact that the longer time series came from larger catchments, which tend to have lower values for specific peak flows than smaller catchments. Our results demonstrate the risk of obtaining incorrect statistical conclusions when statistical analyses and data selection are not considered with due care.
SP-1 regulation of MMP-9 expression requires Ser586 in the PEST domain
Authors: Murthy Shubha , Ryan Alan J. , Carter A. Brent
Published: April 2012

Rac1, a small GTPase, regulates macrophage MMP (matrix metalloproteinase)-9 in an ERK (extracellular-signal-regulated kinase)- and SP (specificity protein)-1-dependent manner. SP-1 contains a PEST (Pro-Glu-Ser-Thr) domain that may modulate protein stability. We hypothesize that Thr578, Ser586 and/or Ser587 in the PEST domain are required for SP-1 stability and MMP-9 expression secondary to activation of ERK, a serine/threonine kinase. We determined the effects of Rac1 and ERK on MMP-9 expression driven by SP-1WT (wild-type) and the SP-1 mutants T578A, S586A and S587A. Expression of WT and mutant SP-1 increased MMP9 promoter activity in alveolar macrophages. However, constitutively active Rac1 suppressed MMP9 promoter activity in cells expressing SP-1WT, SP-1T578A and SP-1S587A, but not SP-1S586A. Furthermore, constitutive ERK activation, which was inhibited by Rac1, significantly increased MMP9 transcription in cells expressing SP-1WT, but not SP-1S586A. As Rac1 activation and ERK inactivation increased degradation of SP-1WT and not SP-1S586A, the results of the present study suggest that SP-1 stability mediated at Ser586 regulates MMP9 transcription. Ex vivo, alveolar macrophages obtained from patients with asbestosis had less MMP-9 expression that was associated with decreased SP-1 expression and ERK activation. These observations demonstrate that Ser586 in the PEST domain of SP-1 is important for MMP9 gene expression in alveolar macrophages and highlight the importance of these proteins in pulmonary fibrosis.
The renin–angiotensin system, bone marrow and progenitor cells
Authors: Durik Matej , Sevá Pessôa Bruno , Roks Anton J. M.
Published: April 2012

Modulation of the RAS (renin–angiotensin system), in particular of the function of the hormones AngII (angiotensin II) and Ang-(1–7) [angiotensin-(1–7)], is an important target for pharmacotherapy in the cardiovascular system. In the classical view, such modulation affects cardiovascular cells to decrease hypertrophy, fibrosis and endothelial dysfunction, and improves diuresis. In this view, excessive stimulation of AT1 receptors (AngII type 1 receptors) fulfils a detrimental role, as it promotes cardiovascular pathogenesis, and this is opposed by stimulation of the AT2 receptor (angiotensin II type 2 receptor) and the Ang-(1–7) receptor encoded by the Mas proto-oncogene. In recent years, this view has been broadened with the observation that the RAS regulates bone marrow stromal cells and stem cells, thus involving haematopoiesis and tissue regeneration by progenitor cells. This change of paradigm has enlarged the field of perspectives for therapeutic application of existing as well as newly developed medicines that alter angiotensin signalling, which now stretches beyond cardiovascular therapy. In the present article, we review the role of AngII and Ang-(1–7) and their respective receptors in haematopoietic and mesenchymal stem cells, and discuss possible pharmacotherapeutical implications.
Validation of reference genes for real-time quantitative PCR normalisation in non-heading Chinese cabbage
Authors: Xiao Dong , Zhang Ning-Wen , Zhao Jian-Jun , Bonnema Guusje , Hou Xi-Lin
Published: April 2012

Non-heading Chinese cabbage is an important vegetable crop that includes pak choi, caixin and several Japanese vegetables like mizuna, mibuna and komatsuna. Gene expression studies are frequently used to unravel the genetics of complex traits and in such studies the proper selection of reference genes for normalisation is crucial. We assessed the expression of 13 candidate reference genes including ACTIN, ACTIN-1, ACTIN-2, GAPDH, Tub_α, CyP, EF1-α, 18S rRNA, UBQ, UBC30, PPR, PP2A and MDH. Their expression stabilities were analysed using two programs, geNorm and NormFinder, in 20 different samples that represent four strategic groups. Results showed that no single gene was uniformly expressed in all tested samples. ACTIN and CyP are proposed as good reference genes when studying developmental stages. CyP, Tub_α and UBC30 are good reference genes when studying different tissues (from flowering to seed set). CyP and Tub_α are the most stable reference genes under biotic stress treatments using the fungi Peronospora parasitica and Alternaria brassicicola. UBC30, EF1-α and ACTIN are recommended for normalisation in abiotic stress studies, including hormone, salt, drought, cold and heath treatments. Moreover, at least five reference genes (ACTIN, CyP, UBC30, EF1-α and UBQ) are required for accurate qRT–PCR data normalisation when studying gene expression across all tested samples.
Visual attention and the acquisition of information in human crowds
Authors: Gallup Andrew C. , Hale Joseph J. , Sumpter David J. T. , Garnier Simon , Kacelnik Alex , Krebs John R. , Couzin Iain D.
Published: April 2012

Pedestrian crowds can form the substrate of important socially contagious behaviors, including propagation of visual attention, violence, opinions, and emotional state. However, relating individual to collective behavior is often difficult, and quantitative studies have largely used laboratory experimentation. We present two studies in which we tracked the motion and head direction of 3,325 pedestrians in natural crowds to quantify the extent, influence, and context dependence of socially transmitted visual attention. In our first study, we instructed stimulus groups of confederates within a crowd to gaze up to a single point atop of a building. Analysis of passersby shows that visual attention spreads unevenly in space and that the probability of pedestrians adopting this behavior increases as a function of stimulus group size before saturating for larger groups. We develop a model that predicts that this gaze response will lead to the transfer of visual attention between crowd members, but it is not sufficiently strong to produce a tipping point or critical mass of gaze-following that has previously been predicted for crowd dynamics. A second experiment, in which passersby were presented with two stimulus confederates performing suspicious/irregular activity, supports the predictions of our model. This experiment reveals that visual interactions between pedestrians occur primarily within a 2-m range and that gaze-copying, although relatively weak, can facilitate response to relevant stimuli. Although the above aspects of gaze-following response are reproduced robustly between experimental setups, the overall tendency to respond to a stimulus is dependent on spatial features, social context, and sex of the passerby.
Cenozoic imprints on the phylogenetic structure of palm species assemblages worldwide
Authors: Kissling W. Daniel , Eiserhardt Wolf L. , Baker William J. , Borchsenius Finn , Couvreur Thomas L. P. , Balslev Henrik , Svenning Jens-Christian
Published: April 2012

Despite long-standing interest in the origin and maintenance of species diversity, little is known about historical drivers of species assemblage structure at large spatiotemporal scales. Here, we use global species distribution data, a dated genus-level phylogeny, and paleo-reconstructions of biomes and climate to examine Cenozoic imprints on the phylogenetic structure of regional species assemblages of palms (Arecaceae), a species-rich plant family characteristic of tropical ecosystems. We find a strong imprint on phylogenetic clustering due to geographic isolation and in situ diversification, especially in the Neotropics and on islands with spectacular palm radiations (e.g., Madagascar, Hawaii, and Cuba). Phylogenetic overdispersion on mainlands and islands corresponds to biotic interchange areas. Differences in the degree of phylogenetic clustering among biogeographic realms are related to differential losses of tropical rainforests during the Cenozoic, but not to the cumulative area of tropical rainforest over geological time. A largely random phylogenetic assemblage structure in Africa coincides with severe losses of rainforest area, especially after the Miocene. More recent events also appear to be influential: phylogenetic clustering increases with increasing intensity of Quaternary glacial-interglacial climatic oscillations in South America and, to a lesser extent, Africa, indicating that specific clades perform better in climatically unstable regions. Our results suggest that continental isolation (in combination with limited long-distance dispersal) and changing climate and habitat loss throughout the Cenozoic have had strong impacts on the phylogenetic structure of regional species assemblages in the tropics.
Pay-what-you-want, identity, and self-signaling in markets
Authors: Gneezy Ayelet , Gneezy Uri , Riener Gerhard , Nelson Leif D.
Published: April 2012

We investigate the role of identity and self-image consideration under “pay-what-you-want” pricing. Results from three field experiments show that often, when granted the opportunity to name the price of a product, fewer consumers choose to buy it than when the price is fixed and low. We show that this opt-out behavior is driven largely by individuals’ identity and self-image concerns; individuals feel bad when they pay less than the “appropriate” price, causing them to pass on the opportunity to purchase the product altogether.