bluuebunny/crossref_metadata_2025 huggingface dataset:
Volumetric imaging of erythrocytes using label‐free multiphoton photoacoustic microscopy
Authors: Shelton Ryan L. , Mattison Scott P. , Applegate Brian E.
Published: August 2013

Photoacoustic microscopy (PAM) is an imaging modality well suited to mapping vasculature and other strong absorbers in tissue. However, one of the primary drawbacks to PAM when used for high‐resolution imaging is the relatively poor axial resolution due to the inverse dependence on the transducer bandwidth. While submicron lateral resolution PAM can be achieved by tightly focusing the excitation light, the axial resolution is fundamentally limited to 10s of microns for typical transducer frequencies. Here we present a multiphoton PAM technique called transient absorption ultrasonic microscopy (TAUM), which results in a completely optically resolved voxel with an experimentally measured axial resolution of 1.5 microns. This technique is demonstrated by imaging individual red blood cells in three dimensions in blood smear and ex vivo tissues. To the best of our knowledge, this is the first demonstration of fully resolved, volumetric photoacoustic imaging of erythrocytes. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Low cytotoxic tissue adhesive based on oxidized dextran and epsilon‐poly‐l‐lysine
Authors: Hyon Suong‐Hyu , Nakajima Naoki , Sugai Hajime , Matsumura Kazuaki
Published: August 2013

A novel adhesive hydrogel consisting of dextran and epsilon‐poly(l‐lysine) (dextran‐PL) with multiple biomedical applications was developed. Periodate oxidation in aqueous media almost stoichiometrically introduces aldehyde groups in dextran molecules, and aldehyde dextran can react with the primary amino groups in epsilon‐PL (ɛ‐PL) at neutral pH to form a hydrogel. The gelation time of the hydrogel can be easily controlled by the extent of oxidation in dextran and of the acylation in ɛ‐PL by anhydrides. The shear adhesion strength of dextran‐PL was 10 times higher than that of fibrin glue, when wet collagen sheets were selected as test specimens. The cytotoxicity of aldehyde dextran and ɛ‐PL were 1000 times lower than that of glutaraldehyde and poly(allylamine). The considerably low cytotoxicity of aldehyde dextran could be ascribed to its low reactivity with amine species when compared with glutaraldehyde. In contrast, a high reactivity of amino groups in ɛ‐PL was observed when compared with glycine, l‐lysine, and gelatin, which could be explained by their poor dissociation at neutral pH, thus leading to low cytotoxicity. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2511–2520, 2014.
A comparison of polymer and polymer–hydroxyapatite composite tissue engineered scaffolds for use in bone regeneration. An in vitro and in vivo study
Authors: Tayton E. , Purcell M. , Aarvold A. , Smith J. O. , Briscoe A. , Kanczler J. M. , Shakesheff K. M. , Howdle S. M. , Dunlop D. G. , Oreffo R. O. C.
Published: August 2013

Previous in vitro work demonstrated porous PLA and PLGA both had the mechanical strength and sustained the excellent skeletal stem cell (SSC) growth required of an osteogenic bonegraft substitute, for use in impaction bone grafting. The purpose of this investigation was to assess the effects of the addition of hydroxyapatite (HA) to the scaffolds before clinical translation. PLA, PLA+10% HA, PLGA, and PLGA+10% HA were milled and impacted into discs before undergoing a standardized shear test. Cellular compatibility analysis followed 14 days incubation with human skeletal stems cells (SSC). The best two performing polymers were taken forward for in vivo analysis. SSC seeded polymer discs were implanted subcutaneously in mice. All polymers had superior mechanical shear strength compared with allograft (p < 0.01). Excellent SSC survival was demonstrated on all polymers, but the PLA polymers showed enhanced osteoblastic activity (ALP assay p < 0.01) and collagen‐1 formation. In vivo analysis was performed on PLA and PLA+10% HA. MicroCT analysis revealed increased bone formation on the PLA HA (p < 0.01), and excellent neo‐vessel formation in both samples. Histology confirmed evidence of de novo bone formation. PLA HA showed both enhanced osteoinductive and osteogenic capacity. This polymer composite has been selected for scaled‐up experimentation before clinical translation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2613–2624, 2014.
Synthesis and characterization of biomimetic citrate‐based biodegradable composites
Authors: Tran Richard T. , Wang Liang , Zhang Chang , Huang Minjun , Tang Wanjin , Zhang Chi , Zhang Zhongmin , Jin Dadi , Banik Brittany , Brown Justin L. , Xie Zhiwei , Bai Xiaochun , Yang Jian
Published: August 2013

Natural bone apatite crystals, which mediate the development and regulate the load‐bearing function of bone, have recently been associated with strongly bound citrate molecules. However, such understanding has not been translated into bone biomaterial design and osteoblast cell culture. In this work, we have developed a new class of biodegradable, mechanically strong, and biocompatible citrate‐based polymer blends (CBPBs), which offer enhanced hydroxyapatite binding to produce more biomimetic composites (CBPBHAs) for orthopedic applications. CBPBHAs consist of the newly developed osteoconductive citrate‐presenting biodegradable polymers, crosslinked urethane‐doped polyester and poly (octanediol citrate), which can be composited with up to 65 wt % hydroxyapatite. CBPBHA networks produced materials with a compressive strength of 116.23 ± 5.37 MPa comparable to human cortical bone (100–230 MPa), and increased C2C12 osterix gene and alkaline phosphatase gene expression in vitro. The promising results above prompted an investigation on the role of citrate supplementation in culture medium for osteoblast culture, which showed that exogenous citrate supplemented into media accelerated the in vitro phenotype progression of MG‐63 osteoblasts. After 6 weeks of implantation in a rabbit lateral femoral condyle defect model, CBPBHA composites elicited minimal fibrous tissue encapsulation and were well integrated with the surrounding bone tissues. The development of citrate‐presenting CBPBHA biomaterials and preliminary studies revealing the effects of free exogenous citrate on osteoblast culture shows the potential of citrate biomaterials to bridge the gap in orthopedic biomaterial design and osteoblast cell culture in that the role of citrate molecules has previously been overlooked. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2521–2532, 2014.
Effect of the hydration on the biomechanical properties in a fibrin‐agarose tissue‐like model
Authors: Scionti Giuseppe , Moral Monica , Toledano Manuel , Osorio Raquel , Durán J. D. G. , Alaminos Miguel , Campos Antonio , López‐López Modesto T.
Published: August 2013

The effect of hydration on the biomechanical properties of fibrin and fibrin‐agarose (FA) tissue‐like hydrogels is reported. Native hydrogels with approximately 99.5% of water content and hydrogels with water content reduced until 90% and 80% by means of plastic compression (nanostructuration) were generated. The biomechanical properties of the hydrogels were investigated by tensile, compressive, and shear tests. Experimental results indicate that nanostructuration enhances the biomechanical properties of the hydrogels. This improvement is due to the partial draining of the water that fills the porous network of fibers that the plastic compression generates, which produces a denser material, as confirmed by scanning electron microscopy. Results also indicate that the characteristic compressive and shear parameters increase with agarose concentration, very likely due to the high water holding capacity of agarose, which reduces the compressibility and gives consistency to the hydrogels. However, results of tensile tests indicate a weakening of the hydrogels as agarose concentration increases, which evidences the anisotropic nature of these biomaterials. Interestingly, we found that by adjusting the water and agarose contents it is possible to tune the biomechanical properties of FA hydrogels for a broad range, within which the properties of many native tissues fall. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2573–2582, 2014.
Putting Molecules in Their Place
Authors: Cinquin Bertrand P. , Do Myan , McDermott Gerry , Walters Alison D. , Myllys Markko , Smith Elizabeth A. , Cohen‐Fix Orna , Le Gros Mark A. , Larabell Carolyn A.
Published: August 2013

Each class of microscope is limited to imaging specific aspects of cell structure and/or molecular organization. However, imaging the specimen by complementary microscopes and correlating the data can overcome this limitation. Whilst not a new approach, the field of correlative imaging is currently benefitting from the emergence of new microscope techniques. Here we describe the correlation of cryogenic fluorescence tomography (CFT) with soft X‐ray tomography (SXT). This amalgamation of techniques integrates 3D molecular localization data (CFT) with a high‐resolution, 3D cell reconstruction of the cell (SXT). Cells are imaged in both modalities in a near‐native, cryopreserved state. Here we describe the current state of the art in correlative CFT‐SXT, and discuss the future outlook for this method. J. Cell. Biochem. 115: 209–216, 2014. © 2013 Wiley Periodicals, Inc.
Microscopic evaluation of vesicles shed by erythrocytes at elevated temperatures
Authors: Moore Timothy , Sorokulova Iryna , Pustovyy Oleg , Globa Ludmila , Pascoe David , Rudisill Mary , Vodyanoy Vitaly
Published: August 2013

The images of human erythrocytes and vesicles were analyzed by a light microscopy system with spatial resolution of better than 90 nm. The samples were observed in an aqueous environment and required no freezing, dehydration, staining, shadowing, marking, or any other manipulation. Temperature elevation resulted in significant concentration increase of structurally transformed erythrocytes (echinocytes) and vesicles in the blood. The process of vesicle separation from spiculated erythrocytes was video recorded in real time. At a temperature of 37°C, mean vesicle concentrations and diameters were found to be 1.50 ± 0.35 × 106 vesicles per microliter and 0.365 ± 0.065 μm, respectively. The vesicle concentration increased approximately threefold as the temperature increased from 37 to 40°C. It was estimated that 80% of all vesicles found in the blood are smaller than 0.4 μm. Accurate account of vesicle numbers and dimensions suggest that 86% of the lost erythrocyte material is lost not by vesiculation but by another, as yet, unknown mechanism. Microsc. Res. Tech. 76:1163–1170, 2013. © 2013 Wiley Periodicals, Inc.
Temperature trends in the tropical upper troposphere and lower stratosphere: Connections with sea surface temperatures and implications for water vapor and ozone
Authors: Garfinkel C. I. , Waugh D. W. , Oman L. D. , Wang L. , Hurwitz M. M.
Published: August 2013

Satellite observations and chemistry‐climate model experiments are used to understand the zonal structure of tropical lower stratospheric temperature, water vapor, and ozone trends. The warming in the tropical upper troposphere over the past 30 years is strongest near the Indo‐Pacific warm pool, while the warming trend in the western and central Pacific is much weaker. In the lower stratosphere, these trends are reversed: the historical cooling trend is strongest over the Indo‐Pacific warm pool and is weakest in the western and central Pacific. These zonal variations are stronger than the zonal‐mean response in boreal winter. Targeted experiments with a chemistry‐climate model are used to demonstrate that sea surface temperature (hereafter SST) trends are driving the zonal asymmetry in upper tropospheric and lower stratospheric tropical temperature trends. Warming SSTs in the Indian Ocean and in the warm pool region have led to enhanced moist heating in the upper troposphere, and in turn to a Gill‐like response that extends into the lower stratosphere. The anomalous circulation has led to zonal structure in the ozone and water vapor trends near the tropopause, and subsequently to less water vapor entering the stratosphere. The radiative impact of these changes in trace gases is smaller than the direct impact of the moist heating. Projected future SSTs appear to drive a temperature and water vapor response whose zonal structure is similar to the historical response. In the lower stratosphere, the changes in water vapor and temperature due to projected future SSTs are of similar strength to, though slightly weaker than, that due directly to projected future CO2, ozone, and methane.
On the Polarity and Monopolarity of Graphs
Authors: Churchley Ross , Huang Jing
Published: August 2013

Polarity and monopolarity are properties of graphs defined in terms of the existence of certain vertex partitions; graphs with polarity and monopolarity are respectively called polar and monopolar graphs. These two properties commonly generalize bipartite and split graphs, but are hard to recognize in general. In this article we identify two classes of graphs, triangle‐free graphs and claw‐free graphs, restricting to which provide novel impact on the complexity of the recognition problems. More precisely, we prove that recognizing polarity or monopolarity remains NP‐complete for triangle‐free graphs. We also show that for claw‐free graphs the former is NP‐complete and the latter is polynomial time solvable. This is in sharp contrast to a recent result that both polarity and monopolarity can be recognized in linear time for line graphs. Our proofs for the NP‐completeness are simple reductions. The polynomial time algorithm for recognizing the monopolarity of claw‐free graphs uses a subroutine similar to the well‐known breadth‐first search algorithm and is based on a new structural characterization of monopolar claw‐free graphs, a generalization of one for monopolar line graphs obtained earlier.
Average Distance, Independence Number, and Spanning Trees
Authors: Mukwembi Simon
Published: August 2013

Let G be a connected graph of order n and independence number α. We prove that G has a spanning tree with average distance at most , if , and at most , if . As a corollary, we obtain, for n sufficiently large, an asymptotically sharp upper bound on the average distance of G in terms of its independence number. This bound, apart from confirming and improving on a conjecture of Graffiti [8], is a strengthening of a theorem of Chung [1], and that of Fajtlowicz and Waller [8], on average distance and independence number of a graph.
Diazepam treatment blocks the elevation of hippocampal activity and the accelerated proliferation of hippocampal neural stem cells after focal cerebral ischemia in mice
Authors: Nochi Rokuya , Kaneko Jun , Okada Natsumi , Terazono Yasushi , Matani Ayumu , Hisatsune Tatsuhiro
Published: August 2013

Hippocampal neurogenesis is accelerated during the elevation of hippocampal neural activities under both physiological and pathophysiological conditions. One of these conditions, middle cerebral artery occlusion (MCAO), induces both the hyperactivities of hippocampal network and the elevation of neural stem cell (NSC) proliferation. However, the causal relationship between the elevated activity and the elevation of NSC proliferation is still unclear. In this study, to block the elevation of hippocampal activity after MCAO in mice, we utilized a typical γ‐aminobutyric acid type A (GABAA) receptor active modulator, diazepam. With MCAO mice treated with diazepam, we observed complete disappearance of the elevation of hippocampal activity. Additionally, the diazepam treatment blocked the elevation of NSC proliferation after MCAO. From this result, it is speculated that the increased NSC proliferation is blocked by the suppression of elevated neural activity. However, diazepam might have effects other than the suppression of hippocampal activity, so we performed additional experiment and found that diazepam did not affect the number of bromodeoxyuridine‐positive cells under the normal condition, whereas the GABA agonist pentobarbital stimulated NSC/neural progenitor cell proliferation and differentiation. Next, we evaluated the expression of the diazepam‐binding inhibitor (DBI) protein and found that the cells expressed DBI in soma and on the surface of cell membrane. From these observations, we can propose that diazepam blocks the elevation of hippocampal activity and also NSC proliferation after MCAO. © 2013 Wiley Periodicals, Inc.
Axonal fasciculation and the role of polysialic acid‐neural cell adhesion molecule in rat cortical neurons
Authors: Wakade Chandramohan G. , Mehta Shyamal H. , Maeda Manebu , Webb R. Clinton , Chiu Fung‐Chow
Published: August 2013

Axonal fasciculation is a mechanism deployed by growing axons to reach their targets during development of the nervous system. Published data have suggested the involvement of neuronal cell adhesion molecules (NCAM) in axonal fasciculation. We have characterized the formation of axonal fascicles in serum‐free, primary cultures of cortical neurons from embryonic rat brains. Unlike the published data, axonal fascicles in our system have a unique morphology: they are waveform, are rarely thicker than 20 μm, and can reach up to several millimeters in length. We observed an age and time dependence in the formation of fascicles. They formed only in cultures from embryonic day 15–17 brain and only between 4 days in vitro (DIV) and 11 DIV. Electron microscopy showed that the fascicles consisted of mostly axonal processes. Immunocytochemical staining confirmed that the fascicles were positive for the 66‐kDa neurofilament protein, NF66, but they contained few, if any, microtubule‐associated protein‐2‐positive or glial fibrillary acidic protein‐positive processes. Polysialic acids appeared to be critical in the formation of fascicles. Neuraminidase treatment prevented the formation of fascicles when added before 5 DIV. Addition of a specific inhibitor blocked the effect of neuraminidase. The cortical neurons in our model shared several important features with axon fasciculation in vivo and may provide a unique system for studying the molecular mechanisms involved in the formation of axonal tracts in the brain. © 2013 Wiley Periodicals, Inc.
An Empirical Examination of the Influence of Corporate Vision on Internationalization
Authors: Singal Ajay Kumar , Jain Arun Kumar
Published: August 2013

Internationalizing firms need to develop mindset‐based capabilities to address the complexity of operating in multiple contexts.
An Isomorphism Perspective to FDI‐Based Entry‐Mode Strategies of Emerging Market Firms — A Conceptual Model
Authors: Mukundhan K. V. , Nandakumar M. K.
Published: August 2013

Emerging market firms operating in developed markets face high environmental uncertainties and identifying appropriate referent groups for behavioral imitation improves the likelihood of firm survival.
Value Creation on Bilateral Cross‐Border Joint Ventures: Evidence from India
Authors: Dhir Sanjay , Mital Amita
Published: August 2013

Partner selection criteria, absorptive capacity, and bargaining power explain the relationship between motives, perceived value criteria, and value creation of cross‐border joint ventures.
Strategic Change and Decision Making in an Emerging Nation: An Exploratory Assessment of Iranian Manufacturing Firms
Authors: Zamani Somayeh , Parnell John A. , Labbaf Hassan , O'Regan Nicholas
Published: August 2013

Businesses that combined cost leadership and differentiation strategies reported the greatest satisfaction with overall performance, but political and economic instability associated with trade sanctions continue to be a key concern for executives in Iran.
Purification, characterization, and properties of an alkaline protease produced bySerratia marcescensS3‐R1inhabiting Korean ginseng rhizosphere
Authors: Nam Myoung Soo , Whang Kyung Sook , Choi Seong Hyun , Bae Hyoung Churl , Kim Yoo Kyeong , Park Young W
Published: August 2013

BACKGROUND

An alkaline protease produced by theSerratia marcescensS3‐R1which inhabits in the Korean ginseng rhizosphere was investigated. The purposes of this study were to characterize and purify the bacterial enzyme by four different purification steps: precipitation of enzyme fraction by ammonium sulfate, loading the enzyme pellets on aDEAE–Sepharose anion‐exchange chromatograph, separation of the fraction containing enzyme activity by fast protein liquid Mono Q chromatography and identification of the single‐band fraction by sodium dodecyl sulfate–polyacrylamide gel electrophoresis, and then quantification of the single‐band fraction by reverse‐phase high‐performance liquid chromatography.

RESULTS

The molecular weight of the purified protease was estimated as 50 308 Da by matrix‐assisted laser desorption ionization time‐of‐flight analysis. The N‐terminal amino acid sequence of the protease was identified as Ala‐Val‐Thr‐Ile‐Glu‐Asp‐Ala‐Val‐Asp‐Asp, and the enzyme belongs to the metalloprotease family. The optimal activities of the protease occurred atpH7–9 and a temperature 40 °C. The ranges ofpHand thermal stability of the enzyme were at 7–10 and 30–40 °C, respectively.

CONCLUSION

The alkaline protease was successfully purified and characterized from the bacteriumSerratia marcescensS3‐R1, which has potential for industrial application, including milk protein hydrolysates. © 2013 Society of Chemical Industry
Method to predict gas chromatographic response factors for the trace‐level analysis of volatile organic compounds based on the effective carbon number concept
Authors: Szulejko Jan E. , Kim Yong‐Hyun , Kim Ki‐Hyun
Published: August 2013

A procedure has been developed to estimate GC–MS response factors based on the theory of effective carbon number defined as the sum of the carbon number and carbon number equivalent for each selected molecular descriptor (multiplied by its number of occurrences) in each compound's molecular structure. As a means to validate the effective carbon number procedure for GC–MS analysis, a test suite of 19 volatile organic compounds was analyzed by the sorbent‐tube thermal desorption method. In the effective carbon number procedure, the carbon number equivalent for each descriptor was determined to yield the optimal linear plots between response factor versus the effective carbon number with the maximum R2 (>0.975) and the minimum mean absolute error (<5%). Effective carbon number analysis is validated as a potent approach to estimate response factor values for most compounds amenable to the sorbent‐tube thermal desorption GC–MS method. Overall, it is concluded that the application of response factor versus effective carbon number relationship can produce fairly reliable prediction with reduced errors relative to other comparable procedures such as the response factor versus the carbon number approach.
Improved MIN6 β‐Cell Function on Self‐Assembled Peptide Amphiphile Nanomatrix Inscribed with Extracellular Matrix‐Derived Cell Adhesive Ligands
Authors: Lim Dong‐Jin , Antipenko Sergey V. , Vines Jeremy B. , Andukuri Adinarayana , Hwang Patrick T. J. , Hadley Nathan T. , Rahman Shibli M. , Corbett John A. , Jun Ho‐Wook
Published: August 2013

Understanding the role of the pancreatic extracellular matrix (ECM) in supporting islet survival and function drives the pursuit to create biomaterials that imitate and restore the pancreatic ECM microenvironment. To create an ECM mimic holding bioinductive cues for β‐cells, self‐assembled peptide amphiphiles (PAs) inscribed with four selected ECM‐derived cell adhesive ligands are synthesized. After 7 days, compared to control groups cultured on biologically inert substrates, MIN6 β‐cells cultured on PAs functionalized with YIGSR and RGDS cell adhesive ligands exhibit elevated insulin secretion in responses to glucose and also form β‐cell clusters. These findings suggest that the self‐assembled PA nanomatrix may be utilized to improve pancreatic islet transplantation for treating type 1 diabetes.
Synthesis of 6‐O‐Poly(ϵ‐caprolactone)‐L‐ascorbic Acid and its Controlled Release from Supramolecular Polymer Micelles
Authors: Li Feifei , Chen Bin , Ping Zhaohua , Jia Xiangxiang , Guo Xin , Xiao Longqiang , Liu Lijian
Published: August 2013

Lipophilic 6‐O‐poly (ϵ‐caprolactone)‐L‐ascorbic acid (AA‐6‐PCL) is synthesized through ROP of ϵ‐caprolactone (CL). The number of repeating CL units in the polymer chain varies from 6 to 19. AA‐6‐PCL loaded supramolecular polymer micelles (SMPMs) are constructed with β‐cyclodextrin (β‐CD) and PCL as blocks. Transmission electron microscopy images show a nanospheric morphology of the micelles with a size range of 43.3 ± 5.0 nm. The drug loading contents are 22.53–39.23% for AA‐6‐PCL. AA‐6‐PCL exhibits high radical scavenging capacity (93.96–96.73%) and efficient scavenging potency, and a cytotoxicity study proves the excellent cytocompatibility of AA‐6‐PCL loaded β‐CD/PCL SMPMs, which altogether herald their potential application in the study of the induced pluripotent stem cells.
Thymine Modified Amphiphilic Biodegradable Copolymers for Photo‐Cross‐Linked Micelles as Stable Drug Carriers
Authors: Kuang Huihui , He Hongyan , Hou Jie , Xie Zhigang , Jing Xiabin , Huang Yubin
Published: August 2013

A photo‐cross‐linked micelle is synthesized via photodimerization of thymine moieties fabricated from amphiphilic block copolymers (mPEG‐b‐P(LA‐co‐MPT). The crosslinking behavior is monitored by UV‐Vis spectra and 1H NMR. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed that cross‐linked micelles had smaller sizes than their uncross‐linked precursors. In vitro studies reveal that cross‐linking of the micelle cores results in a slow drug release and faster cellular uptake in comparison with uncross‐linked ones in MCF‐7 and Hela cells. Moreover, the paclitaxel (PTX)‐loaded core‐cross‐linked micelles exhibit similar anticancer efficacy as free PTX. This work provides a convenient tool for designing a more stable structure in the blood circulation to realize a controlled drug delivery.
Chitosan‐Based Nanocoatings for Hypothermic Storage of Living Cells
Authors: Bulwan Maria , Antosiak‐Iwańska Magdalena , Godlewska Ewa , Granicka Ludomira , Zapotoczny Szczepan , Nowakowska Maria
Published: August 2013

The formation of ultrathin chitosan‐based nanocoating on HL‐60 model cells and their protective function in hypothermic storage are presented. HL‐60 cells are encapsulated in ultrathin shells by adsorbing cationic and anionic chitosan derivatives in a stepwise, layer‐by‐layer, procedure carried out in an aqueous medium under mild conditions. The chitosan‐based films are also deposited on model lipid bilayer and the interactions are studied using ellipsometry and atomic force microscopy. The cells covered with the chitosan‐based films and stored at 4 °C for 24 h express viability comparable to that of the control sample incubated at 37 °C, while the unprotected cells stored under the same conditions do not show viability. It is shown that the chitosan‐based shell protects HL‐60 cells against damaging effect of hypothermic storage. Such nanocoatings provide protection, mechanical stability, and support the cell membrane, while ensuring penetration of small molecules such as nutrients/gases what is essential for cell viability.
Metastable β‐Bi2O3 Nanoparticles with Potential for Photocatalytic Water Purification Using Visible Light Irradiation
Authors: Schlesinger Maik , Weber Marcus , Schulze Steffen , Hietschold Michael , Mehring Michael
Published: August 2013

Invited for this month′s cover is the group of Prof. Michael Mehring. The cover picture shows the degradation of the model dye rhodamine B (RhB) in water using β‐Bi2O3 nanoparticles as photocatalyst, which was prepared from pre‐organized bismuth oxido clusters. For more details, see the Full Paper on p. 146 ff.

Read the full text of the article at 10.1002/open.201300013
Electrical actuation of electroresponsive hydrogels based on poly(acrylamide‐co‐acrylic acid)/graphite suitable for biomedical applications
Authors: Boruah Monalisha , Phukon Pinkee , jyoti Saikia Bhaskar , Dolui S.K.
Published: August 2013

A pH‐sensitive composite hydrogel based on poly(acrylamide‐co‐acrylic acid)/graphite was prepared by solution polymerization process in presence of redox initiator potassium persulfate/N,N,N′,N′‐tetramethylethylenediamine and cross‐linker (ethylene glycol dimethylacrylate). The structures of the hydrogels were confirmed using Fourier transform infrared, X‐ray diffraction, and scanning electron microscopy (SEM) study. Tensile strengths of the hydrogels were determined by using a universal tensile machine, whereas the electrical conductivities of the hydrogels were evaluated using Four‐probe method. The influence of cross‐linker, graphite content, and temperature on the conductivity of the hydrogel was also investigated. The bending behavior of the conducting hydrogels was investigated by exposing the hydrogels under electric field in aqueous medium. By studying the swelling ratio of the polymer synthesized under different conditions, optimization conditions were found for a polymer with the highest swelling ratio. Also, the hemolytic potentiality test revealed that prepared hydrogels are biocompatible in nature. POLYM. COMPOS., 35:27–36, 2014. © 2013 Society of Plastics Engineers
US‐based emergency department visits for fluoroquinolone‐associated hypersensitivity reactions
Authors: Jones S. Christopher , Budnitz Daniel S. , Sorbello Alfred , Mehta Hina
Published: August 2013

Purpose

To estimate the rate of hypersensitivity reactions per 100,000 prescription dispensings of fluoroquinolones based on care rendered in a nationally representative sample of US hospital emergency departments (ED).

Methods

We analyzed the frequency of fluoroquinolone‐associated hypersensitivity reactions using the National Electronic Injury Surveillance System‐Cooperative Adverse Drug Event Surveillance system (2004–2010) in conjunction with US retail outpatient prescription data from IMS Health (2004–2010). We further categorized reaction severity into three subgroups (mild, moderate, and severe).

Results

Based on 1422 cases of fluoroquinolone‐associated hypersensitivity reactions and national drug utilization projections, we estimated risk of hypersensitivity reactions for moxifloxacin, ciprofloxacin, and levofloxacin. The absolute risk of a fluoroquinolone‐related hypersensitivity reaction of any severity was low (44.0 (95% CI 34.8–53.3) ED visits/100,000 prescriptions); however, we identified a statistically significant difference in the relative risk (rate ratios) of seeking care in an ED attributed to moxifloxacin hypersensitivity compared to either levofloxacin or ciprofloxacin. For all reaction severities, the estimated ED visits/100,000 prescriptions were 141.3 (95% CI 99.9–182.7) for moxifloxacin, 40.8 (95% CI 31.5–50.0) for levofloxacin, and 26.3 (95% CI 20.8–31.9) for ciprofloxacin. When the rates were stratified by reaction severity category (mild or moderate–severe), moxifloxacin continued to be implicated in more ED visits per 100,000 prescriptions dispensed than either levofloxacin or ciprofloxacin.

Conclusion

Fluoroquinolones may cause hypersensitivity reactions requiring care in an ED, and relative to use, the rate of moxifloxacin‐related hypersensitivity reactions is higher compared to levofloxacin or ciprofloxacin. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Mutagenic dissection of the sequence determinants of protein folding, recognition, and machine function
Authors: Sauer Robert T.
Published: August 2013

Understanding the relationship between the amino‐acid sequence of a protein and its ability to fold and to function is one of the major challenges of protein science. Here, cases are reviewed in which mutagenesis, biochemistry, structure determination, protein engineering, and single‐molecule biophysics have illuminated the sequence determinants of folding, binding specificity, and biological function for DNA‐binding proteins and ATP‐fueled machines that forcibly unfold native proteins as a prelude to degradation. In addition to structure‐function relationships, these studies provide information about folding intermediates, mutations that accelerate folding, slow unfolding, and stabilize proteins against denaturation, show how new binding specificities and folds can evolve, and reveal strategies that proteolytic machines use to recognize, unfold, and degrade thousands of distinct substrates.
How long does it take to equilibrate the unfolded state of a protein?
Authors: Levy Ronald M. , Dai Wei , Deng Nan‐Jie , Makarov Dmitrii E.
Published: August 2013

How long does it take to equilibrate the unfolded state of a protein? The answer to this question has important implications for our understanding of why many small proteins fold with two state kinetics. When the equilibration within the unfolded state U is much faster than the folding, the folding kinetics will be two state even if there are many folding pathways with different barriers. Yet the mean first passage times (MFPTs) between different regions of the unfolded state can be much longer than the folding time. This seems to imply that the equilibration within U is much slower than the folding. In this communication we resolve this paradox. We present a formula for estimating the time to equilibrate the unfolded state of a protein. We also present a formula for the MFPT to any state within U, which is proportional to the average lifetime of that state divided by the state population. This relation is valid when the equilibration within U is very fast as compared with folding as it often is for small proteins. To illustrate the concepts, we apply the formulas to estimate the time to equilibrate the unfolded state of Trp‐cage and MFPTs within the unfolded state based on a Markov State Model using an ultra‐long 208 microsecond trajectory of the miniprotein to parameterize the model. The time to equilibrate the unfolded state of Trp‐cage is ∼100 ns while the typical MFPTs within U are tens of microseconds or longer.
Surface adsorption considerations when working with amyloid fibrils in multiwell plates and Eppendorf tubes
Authors: Murray Amber N. , Palhano Fernando L. , Bieschke Jan , Kelly Jeffery W.
Published: August 2013

The accumulation of cross‐β‐sheet amyloid fibrils is the hallmark of amyloid diseases. Recently, we reported the discovery of amyloid disaggregase activities in extracts from mammalian cells and Caenorhabditis elegans. However, we have discovered a problem with the interpretation of our previous results as Aβ disaggregation in vitro. Here, we show that Aβ fibrils adsorb to the plastic surface of multiwell plates and Eppendorf tubes. This adsorption is markedly increased in the presence of complex biological mixtures subjected to a denaturing air‐water interface. The time‐dependent loss of thioflavin T fluorescence that we interpreted previously as disaggregation is due to increased adsorption of Aβ amyloid to the surfaces of multiwell plates and Eppendorf tubes in the presence of biological extracts. As the proteins in biological extracts denature over time at the air‐water interface due to agitation/shaking, their adsorption increases, in turn promoting adsorption of amyloid fibrils. We delineate important control experiments that quantify the extent of amyloid adsorption to the surface of plastic and quartz containers. Based on the results described in this article, we conclude that our interpretation of the kinetic fibril disaggregation assay data previously reported in Bieschke et al., Protein Sci 2009;18:2231–2241 and Murray et al., Protein Sci 2010;19:836–846 is invalid when used as evidence for a disaggregase activity. Thus, we correct the two prior publications reporting that worm or mammalian cell extracts disaggregate Aβ amyloid fibrils in vitro at 37°C (see Corrigenda in this issue of Protein Science). We apologize for misinterpreting our previous data and for any confounding experimental efforts this may have caused.
Effects of subclass change on the structural stability of chimeric, humanized, and human antibodies under thermal stress
Authors: Ito Takahiko , Tsumoto Kouhei
Published: August 2013

To address how changes in the subclass of antibody molecules affect their thermodynamic stability, we prepared three types of four monoclonal antibody molecules (chimeric, humanized, and human) and analyzed their structural stability under thermal stress by using size‐exclusion chromatography, differential scanning calorimetry (DSC), circular dichroism (CD), and differential scanning fluoroscopy (DSF) with SYPRO Orange as a dye probe. All four molecules showed the same trend in change of structural stability; the order of the total amount of aggregates was IgG1 < IgG2 < IgG4. We thus successfully cross‐validated the effects of subclass change on the structural stability of antibodies under thermal stress by using four methods. The Th values obtained with DSF were well correlated with the onset temperatures obtained with DSC and CD, suggesting that structural perturbation of the CH2 region could be monitored by using DSF. Our results suggested that variable domains dominated changes in structural stability and that the physicochemical properties of the constant regions of IgG were not altered, regardless of the variable regions fused.
Refinement patterns for ASTDs
Authors: Frappier Marc , Gervais Frédéric , Laleau Régine , Milhau Jérémy
Published: August 2013

This paper introduces three refinement patterns for algebraic state-transition diagrams (
astds
): state refinement, transition refinement and loop-transition refinement. These refinement patterns are derived from practice in using
astds
for specifying information systems and security policies in two industrial research projects. Two refinement relations used in these patterns are formally defined. For each pattern, proof obligations are proposed to ensure preservation of behaviour through refinement. The proposed refinement relations essentially consist in preserving scenarios by replacing abstract events with concrete events, or by introducing new events. Deadlocks cannot be introduced; divergence over new events is allowed in one of the refinement relation. We prove congruence-like properties for these three patterns, in order to show that they can be applied to a subpart of a specification while preserving global properties. These three refinement patterns are illustrated with a simple case study of a complaint management system.
A framework for understanding quality of life in individuals without capacity
Authors: Round Jeff , Sampson Elizabeth L. , Jones Louise
Published: August 2013

Purpose

The wide range of tools and methods developed for measuring and valuing health-related quality of life for use in economic evaluations are appropriate for use in most populations. However, for certain populations, specific tools may need to be developed to reflect the particular needs of that population. Patients without capacity—particularly patients with severe dementia—are such a population. At present, the tools available to economists for measuring and valuing quality of life in these patients lack validity. Here, we seek to understand the framework within which common instruments have been developed, critique these instruments with respect to patients with severely restricted capacity and to develop a new way of thinking about how to value health-related quality of life in such patients.

Method

In this essay, we describe and critique the conceptual framework by which common instruments used for measuring and valuing quality of life have been developed.

Results

We show that current common instruments used for measuring and valuing quality of life in general populations are not appropriate for populations with severely restricted capacity.

Conclusions

We propose a new framework for thinking about quality of life in this population, based on notions of observable person-centred outcomes and utility derived from processes of care.
Clusterförderung mit der „Gemeinschaftsaufgabe“
Authors: Wurpts Klaus , Kirchgeorg Manfred
Published: August 2013

Across almost the entire globe, cluster and networking organisations are being supported at a number of administrative levels to boost regions’ economic competitiveness. Within the framework of the program “Joint Task to Improve the Regional Economic Structure”, launched by the Federal Ministry of Economics and Technology, fifty-two of these organisations exist in Eastern Germany alone. In view of their number, and the fact that many of them have already received promotion twice, or the maximum number of times possible, the funding program and its implementation are now being evaluated in this study—against the background of a scientific critique of the cluster concept and its promotion, as well as the absence of publicly accessible evaluations. Findings reveal a lack of thematic and geographical co-ordination, no evaluation of the promotion provided, and an absence of service orientation among the organisation management.
MALAT‐1 interacts with hnRNP C in cell cycle regulation
Authors: Yang Feng , Yi Fan , Han Xiaorui , Du Quan , Liang Zicai
Published: August 2013

As a conserved non‐coding RNA gene, transcripts of MALAT‐1 localize predominately in the nucleus. However in G2/M cell cycle phase, MALAT‐1 transcripts were surprisingly found to translocate from the nucleus into the cytoplasm. Investigation also found that in this process MALAT‐1 interacts with an abundant nuclear factor, hnRNP C protein. Using a loss‐of‐function assay, we found that down‐regulation of MALAT‐1 expression compromised the cytoplasmic translocation of hnRNP C in the G2/M phase and resulted in G2/M arrest. In addition to characterize the physiological interaction between MALAT‐1 and hnRNP C, our study also highlights the role of MALAT‐1 in cell cycle regulation.
Expert groups in the European Union: A sui generis phenomenon?
Authors: Metz Julia
Published: August 2013

This paper challenges the assumption that the European Union's (EU) unique multi-level governance system leads to distinct policy advisory structures. It focuses on the expert groups that advise the European Commission and examines how they are used in the policy process. Theoretically the relationship between the European Commission and its expert groups is conceptualised as determined by resource dependencies: the EU Commission uses expert groups to acquire expertise, political support and consensus. The assumption that the EU Commission uses its expert groups for multiple purposes beyond the technocratic acquisition of advice is confirmed by a quantitative analysis of their development over time and a qualitative analysis of their use in legislative drafting. These findings reflect those from studies undertaken at other levels of government, which indicates that the role of expert groups in the EU policy process is not a phenomenon sui generis.
CONDOM USE AT SEXUAL DEBUT AMONG CHINESE YOUTH
Authors: GUO WEI , WU ZHENG , SCHIMMELE CHRISTOPH M. , ZHENG XIAOYING
Published: August 2013

Chinese youth represent a high-risk group for sexually transmitted infections and unintended pregnancies, but there is little understanding of their sexual behaviours. Using nationally representative data, this study examines the social and demographic correlates of condom use by Chinese youth at sexual debut. It also examines the relationship context of condom use at sexual debut. The results indicate that condom use at sexual debut is very low in China, confirming that youth are a high-risk group. The results demonstrate that age and educational attainment are the primary indicators of condom use. Early sexual debut associates with a greater risk of unsafe sex at sexual debut and higher educational attainment increases the likelihood of self-protecting behaviours. The likelihood of self-protection also increases when sexual partners plan their sexual debut or discuss contraception beforehand. The results suggest that interventions are needed to provide youth with better knowledge about self-protection.
Taeniases and cysticercosis in Indonesia: past and present situations
Authors: WANDRA TONI , ITO AKIRA , SWASTIKA KADEK , DHARMAWAN NYOMAN S , SAKO YASUHITO , OKAMOTO MUNEHIRO
Published: August 2013

The main aim of this study is to overview the past and present situations of human taeniases and cysticercosis in Indonesia and including future perspectives. Through joint projects from 1996, we have confirmed the occurrence ofTaenia saginata(beef tapeworm) in Bali, ofTaenia solium(pork tapeworm) mainly in Papua and sporadically in Bali, and ofTaenia asiaticain North Sumatra. These taeniases were caused through eating uncooked pork and pig viscera forT. soliumandT. asiatica, respectively, and beef forT. saginata. The distribution of these tapeworms in Indonesia is basically highly restricted by the traditional cultural and religious backgrounds in each island.T. saginatais relatively common in Bali although people consume pork ‘lawar’more than beef ‘lawar’. Taeniases due toT. saginataorT. asiaticaandT. soliumand cysticercosis due toT. soliumhave also been sporadically reported in some other islands. Among these species,T. soliumis exceptional since humans can be infected not only by larval stages (cysticerci) in pork but also by eggs released from human tapeworm carriers. Cysticercosis has been confirmed in Indonesia in humans, pigs and even dogs.
Parasitism and phenotypic change in colonial hosts
Authors: HARTIKAINEN HANNA , FONTES INÊS , OKAMURA BETH
Published: August 2013

Changes in host phenotype are often attributed to manipulation that enables parasites to complete trophic transmission cycles. We characterized changes in host phenotype in a colonial host–endoparasite system that lacks trophic transmission (the freshwater bryozoan Fredericella sultana and myxozoan parasite Tetracapsuloides bryosalmonae). We show that parasitism exerts opposing phenotypic effects at the colony and module levels. Thus, overt infection (the development of infectious spores in the host body cavity) was linked to a reduction in colony size and growth rate, while colony modules exhibited a form of gigantism. Larger modules may support larger parasite sacs and increase metabolite availability to the parasite. Host metabolic rates were lower in overtly infected relative to uninfected hosts that were not investing in propagule production. This suggests a role for direct resource competition and active parasite manipulation (castration) in driving the expression of the infected phenotype. The malformed offspring (statoblasts) of infected colonies had greatly reduced hatching success. Coupled with the severe reduction in statoblast production this suggests that vertical transmission is rare in overtly infected modules. We show that although the parasite can occasionally infect statoblasts during overt infections, no infections were detected in the surviving mature offspring, suggesting that during overt infections, horizontal transmission incurs a trade-off with vertical transmission.