bluuebunny/crossref_metadata_2025 huggingface dataset:
Generation of germ cells in vitro in the era of induced pluripotent stem cells
Authors: Imamura Masanori , Hikabe Orie , Lin Zachary Yu‐Ching , Okano Hideyuki
Published: August 2013

Induced pluripotent stem cells (iPSCs) are stem cells that can be artificially generated via “cellular reprogramming” using gene transduction in somatic cells. iPSCs have enormous potential in stem‐cell biology as they can give rise to numerous cell lineages, including the three germ layers. An evaluation of germ‐line competency by blastocyst injection or tetraploid complementation, however, is critical for determining the developmental potential of mouse iPSCs towards germ cells. Recent studies have demonstrated that primordial germ cells obtained by the in vitro differentiation of iPSCs produce functional gametes as well as healthy offspring. These findings illustrate not only that iPSCs are developmentally similar to embryonic stem cells (ESCs), but also that somatic cells from adult tissues can produce gametes in vitro, that is, if they are reprogrammed into iPSCs. In this review, we discuss past and recent advances in the in vitro differentiation of germ cells using pluripotent stem cells, with an emphasis on ESCs and iPSCs. While this field of research is still at a stage of infancy, it holds great promises for investigating the mechanisms of germ‐cell development, especially in humans, and for advancing reproductive and developmental engineering technologies in the future. Mol. Reprod. Dev. 81: 2–19, 2014. © 2013 Wiley Periodicals, Inc.
Experimental measurement of transversal micro‐ and macro permeability during compression molding of PP/Glass composites
Authors: Gennaro R. , Christmann M. , Greco A. , Rieber G. , Mitschang P. , Maffezzoli A.
Published: August 2013

In this work, a new experimental method is presented, aimed to measure the transversal permeability of fabric reinforcements for composite production. Through‐thickness impregnation of a glass woven fabric with polypropylene matrix was studied during compression molding experiments. The composite thickness was continuously measured during compression molding at different temperatures and pressure levels. The measured composite thickness was used to evaluate the molten front advancement during fabric impregnation. The existence of two different mechanisms of impregnation was highlighted by changes in the slope of the molten front advancement. Optical microscopy confirmed the occurrence of these two different mechanisms: macro‐scale impregnation, associated to void reduction between the bundles (inter‐bundle) occurring at lower times, and micro‐scale impregnation, associated to the flow of the matrix inside each bundle (intra‐bundle), occurring at longer times. Each of the two processes is characterized by a different value of the permeability, calculated according to Darcy law. The intra‐bundle and inter‐bundle permeability were used for calculating the transversal global permeability applying the Papathanasiou model. These values were compared with transversal permeability results evaluated using a low viscosity test fluid. POLYM. COMPOS., 35:105–112, 2014. © 2013 Society of Plastics Engineers
Off‐label use of second generation antipsychotics for post‐traumatic stress disorder in the Department of Veterans Affairs: time trends and sociodemographic, comorbidity, and regional correlates
Authors: Bauer Mark S. , Lee Austin , Li Mingfei , Bajor Laura , Rasmusson Ann , Kazis Lewis E.
Published: August 2013

Purpose

Second generation antipsychotics (SGAs) are widely used for post‐traumatic stress disorder (PTSD), although without strong evidence base. With substantial numbers of veterans returning from Iraq/Afghanistan conflicts with PTSD, it is important to characterize the extent of SGA use and identify associated factors.

Methods

We determined time trends and patient characteristics associated with the use of SGAs in veterans with PTSD, without comorbid schizophrenia or bipolar disorders, using the Department of Veterans Affairs national administrative data 2003–2010.

Results

Among 732 085 veterans with PTSD, 27.6% received an intentional trial of an SGA in 2003–2010. The annual number treated with SGAs almost doubled (45 268 to 84 197, p < 0.001), while prescribing rates decreased (28.6% to 21.5%, p < 0.001). In multivariate analyses, African Americans (odds ratio (OR) = 1.07, 95%confidence interval (CI) = 1.06–1.09) and Hispanics (OR = 1.13, 95%CI = 1.10–1.17) were more likely to receive SGAs than Whites. Strongest clinical associations were with prior diagnosis of depression (OR = 1.96; 95%CI = 1.94–1.99), substance use disorders (OR = 1.86; 95%CI = 1.84–1.88), and other anxiety disorders (OR = 1.27; 95%CI = 1.26–1.29) (all p – < 0.0001) as well as cardiovascular risk factors. Veterans previously deployed to Iraq/Afghanistan had lower likelihood of SGA receipt. Substantial regional differences were demonstrated (South > Northeast; Midwest and West < Northeast; p < 0.0001); regional administrative units (veterans integrated service networks) contributed minimally to regional differences.

Conclusions

Post‐traumatic stress disorder population growth is driving substantial increases in SGA use. Decreasing rates of the Department of Veterans Affairs prescribing may be due to integrated system‐wide mechanisms (e.g., national practice guidelines), although regional variations remain prominent. These analyses provide foundational steps for identifying modifiable provider‐level and organization‐level determinants of SGA prescription in this growing population. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Effect of hybrid reinforcement based on precipitated silica and montmorillonite nanofillers on the mechanical properties of a silicone rubber
Authors: Nik Ismail N.I. , Ansarifar A. , Song M.
Published: August 2013

Silicone rubber (SR) nanocomposites containing precipitated silica (PS), montmorillonite (MMT), and PS/MMT hybrid fillers were prepared through melt‐mixing technique. In the SR/PS/MMT nanocomposite, the hybrid filler weight ratio was increased progressively from 0.4 to 1.7 while keeping the MMT weight constant. The viscosity, cure characteristics, and mechanical properties of the nanocomposites were subsequently measured. The optimum cure time increased, and the scorch time and rate of cure decreased. Furthermore, when the hybrid filler weight ratio was raised to its optimum, the tensile strength, Young's modulus, modulus at 100 and 300% elongation (M100 and M300), elongation at break, stored energy density at break, and hardness of the nanocomposite improved. The stress–strain properties of the nanocomposite with the hybrid filler improved at high deformation in comparison with those containing the PS and MMT fillers. The MMT filler exfoliated in the SR/MMT nanocomposite but did not in the nanocomposites containing the hybrid filler. Notably, the mechanical properties of the nanocomposite benefitted from the hybrid filler. This was due to the filler–filler and filler–rubber network formation in the rubber by the PS particles. Finally, effect of the PS, MMT, and hybrid fillers on the energy loss or hysteresis of the rubber was measured. POLYM. ENG. SCI., 54:1909–1921, 2014. © 2013 Society of Plastics Engineers
Effect of combining ethylene/methyl acrylate/glycidyl methacrylate terpolymer and an organoclay on the toughening of poly(lactic acid)
Authors: Brito Gustavo F. , Agrawal Pankaj , Araújo Edcleide M. , Mélo Tomás J.A.
Published: August 2013

Blends of poly(lactic acid) (PLA) and ethylene/methyl acrylate/glycidyl methacrylate terpolymer (EMA‐GMA) with and without the addition of an organoclay were prepared by melt mixing in a twin screw extruder. Mechanical, morphological, structural, and rheological properties of the systems have been investigated as function of its compositions. The impact strength (IS) of PLA increased with the addition of EMA‐GMA. Furthermore, the addition of 2.5 wt% of organoclay to the PLA/EMA‐GMA blend promoted improvements in the mechanical properties, such as IS, tensile strength, and strain‐at‐break. Further addition of organoclay, 5 wt%, led to a formation of a double percolated network, where the clay particles form bridges across EMA‐GMA droplets and glue them together, however, without coalescence. In addition, morphological and wide‐angle X‐ray scattering analyses evidenced that the clay presents a partially exfoliated structure and that remains inside the EMA‐GMA droplets, probably as a consequence of the approach used to produce the systems. POLYM. ENG. SCI., 54:1922–1930, 2014. © 2013 Society of Plastics Engineers
Polyethylene‐based nanocomposite films: Structure/properties relationship
Authors: Martini Raquel E. , La Tegola Simone , Terenzi Andrea , Kenny José M. , Barbosa Silvia E.
Published: August 2013

Polyethylene (PE) is the most used thermoplastic commodity as a consequence of its convenient cost‐processing‐performance relationship and it can be used in the form of films for food, goods and farming packaging. On the other hand, sepiolite is a high surface area and porosity hydrated magnesium silicate with both remarkable adsorptive and absorptive properties. Thus, PE and sepiolite can combine their properties synergetically to obtain new materials with enhanced properties. In this work, a systematic study of final properties of PE‐sepiolite nanocomposite films was performed to investigate the influence of the sepiolite content and modification on the PE properties. Nanocomposites films with 1, 3, 5 and 10 wt % of sepiolite, with and without surface modification, were prepared by cast film extrusion and tested. The filler dispersion and distribution were evaluated by Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR), whereas the film crystalline morphology was analyzed using Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC) and X‐ray Diffraction (XRD). Final properties as mechanical ones, oxygen permeability and transparency were also studied and related with the film structure. Mechanical properties, crystallization and oxygen permeability were increased maintaining good film translucency. POLYM. ENG. SCI., 54:1931–1940, 2014. © 2013 Society of Plastics Engineers
Structural templates for modeling homodimers
Authors: Kundrotas Petras J. , Vakser Ilya A. , Janin Joël
Published: August 2013

Oligomeric proteins are more abundant in nature than monomeric proteins, and involved in all biological processes. In the absence of an experimental structure, their subunits can be modeled from their sequence like monomeric proteins, but reliable procedures to build the oligomeric assembly are scarce. Template‐based methods, which start from known protein structures, are commonly applied to model subunits. We present a method to model homodimers that relies on a structural alignment of the subunits, and test it on a set of 511 target structures recently released by the Protein Data Bank, taking as templates the earlier released structures of 3108 homodimeric proteins (H‐set), and 2691 monomeric proteins that form dimer‐like assemblies in crystals (M‐set). The structural alignment identifies a H‐set template for 97% of the targets, and in half of the cases, it yields a correct model of the dimer geometry and residue–residue contacts in the target. It also identifies a M‐set template for most of the targets, and some of the crystal dimers are very similar to the target homodimers. The procedure efficiently detects homology at low levels of sequence identities, and points to erroneous quaternary structures in the Protein Data Bank. The high coverage of the target set suggests that the content of the Protein Data Bank already approaches the structural diversity of protein assemblies in nature, and that template‐based methods should become the choice method for modeling oligomeric as well as monomeric proteins.
Light Consulting after Design of Experiments Training: Lessons from a Case Study
Authors: Marco‐Almagro Lluís , Grima Pere , Tort‐Martorell Xavier
Published: August 2013

We present a case study to show some positive and some problematic points regarding light consulting—when none of the parts is fully committed—on Design of Experiments (DOE). The situation is not unusual and frequently occurs after a DOE training course. In fact, the case used as an illustration occurred when advising a team of engineers from an aeronautical industrial company some months after giving them a 32‐h DOE seminar.

A key point is that, in spite of all the inconveniences and pitfalls, it may be a good alternative for the two parts, especially nowadays with all the internet facilities. The case study included in the paper serves as an excuse to give a set of recommendations on how to develop this light consulting approach the best possible way. Copyright © 2013 John Wiley & Sons, Ltd.
BamHI‐A rightward frame 1, an Epstein–Barr virus‐encoded oncogene and immune modulator
Authors: Hoebe Eveline K. , Le Large Tessa Y. S. , Greijer Astrid E. , Middeldorp Jaap M.
Published: August 2013

Epstein–Barr virus (EBV) causes several benign and malignant disorders of lymphoid and epithelial origin. EBV‐related tumors display distinct patterns of viral latent gene expression, of which the BamHI‐A rightward frame 1 (BARF1) is selectively expressed in carcinomas, regulated by cellular differentiation factors including ΔNp63α. BARF1 functions as a viral oncogene, immortalizing and transforming epithelial cells of different origin by acting as a mitogenic growth factor, inducing cyclin‐D expression, and up‐regulating antiapoptotic Bcl‐2, stimulating host cell growth and survival. In addition, secreted hexameric BARF1 has immune evasive properties, functionally corrupting macrophage colony stimulating factor, as supported by recent functional and structural data. Therefore, BARF1, an intracellular and secreted protein, not only has multiple pathogenic functions but also can function as a target for immune responses. Deciphering the role of BARF1 in EBV biology will contribute to novel diagnostic and treatment options for EBV‐driven carcinomas. Herein, we discuss recent insights on the regulation of BARF1 expression and aspects of structure‐function relating to its oncogenic and immune suppressive properties. © 2013 The Authors. Reviews in Medical Virology published by John Wiley & Sons, Ltd.
Trust coercion in the name of usable public key infrastructure
Authors: Zissis Dimitrios , Lekkas Dimitrios
Published: August 2013

We are currently witnessing an alarmingly increasing array of attacks on secure infrastructures used for industrial and commercial purposes. The success of these attacks has relied heavily on an innovative stratagem. This stratagem makes use of digital certificates to devise malicious code or servers as trustworthy, ultimately deceiving end users. This has led to an escalating demand for forged or stolen valid digital certificates on the electronic black market. Certification authorities (CAs) themselves are now coming under fire. Virus reports have surfaced on malicious software whose sole purpose was to grab certificates from within certain CAs' infrastructures. The growing popularity of these attacks is putting in doubt the effectiveness of one of the pillars upon which security in the digital world is built, cryptography and digital signatures. What is to blame? In a phrase, “Trust by default”. To increase the usability of public key infrastructure interactions, a number of CAs are pre‐included in users' browsers and operating systems. These entities are trusted by default, and this trust is now being exploited. In this paper, we shall try to shed light on the true dimensions and implications of “trust by default” in public key infrastructure environments. We attempt to raise awareness about the severity of this kind of attacks, demystify the security challenges and identify unique security threats. We need to ring the alarm about trust‐related issues in online communications. We analyze the issue from an information and communication security perspective and explore the notion of trust relations in this context. We support the doctrine that trust should be built on informed judgment, and this can only be achieved through increased openness. Following this, we put forward for consideration a number of proposals that attempt to overcome the issue at hand, by increasing user‐side awareness and thus solution effectiveness, regarding digital certificate transactions. We present an experimental mechanism that is able to provide users with customized digital certificate repositories based on an open crowd sourcing method. Copyright © 2013 John Wiley & Sons, Ltd.
Privacy‐preserving framework for geosocial applications
Authors: Malina Lukas , Hajny Jan
Published: August 2013

The paper deals with user privacy in geosocial applications. Geosocial applications have become very popular but can misuse user's private data and location. We propose a novel solution that prevents tracking and protects against personal identity and location being misused by external attackers or service providers. The proposed framework provides security and privacy protection for geosocial applications that provide, for example, information sharing, geotagging, and monitoring of people without revealing their identity to unauthorized persons, including the service provider. Unlike current security solutions in geosocial services, our novel framework uses advanced cryptography to secure user privacy. This protection is provided by advanced group signatures ensuring data integrity, authenticity, non‐repudiation, and strong privacy protection. The paper outputs a detailed cryptographic scheme for the protection of privacy in geosocial services and its security analysis. The proposed scheme has also been implemented, and the performance results are outlined in the paper. Copyright © 2013 John Wiley & Sons, Ltd.
Gibbs ensembles for incompatible dependency networks
Authors: Chen Shyh‐Huei , Ip Edward H. , Wang Yuchung J.
Published: August 2013

In most statistical applications, the Gibbs sampler is the method of choice for inference regarding conditionally specified distributions that are compatible. Compatibility ensures that a unique Gibbs distribution exists. For machine learning of complex models such as dependency networks, the conditional models are sometimes incompatible. In this paper, we review an ensemble approach using the Gibbs sampler as the base procedure. A Gibbs ensemble consists of many joint distributions resulting from different scan orders of the same conditional model, and the solution is a weighted sum of the ensemble. The algorithm is scalable and can handle large data sets of high dimensionality. The proposed approach provides joint distributions that conform with the conditional specifications better than the solutions obtained by linear programming and by a fixed‐scan Gibbs sampler alone. Owing to incompatibility, the invariant distribution of a Gibbs sampler is scan‐order dependent. A Gibbs ensemble is the collection of joint distributions estimated from the Gibbs samples of different scan orders.WIREs Comput Stat2013, 5:478–485. doi: 10.1002/wics.1273

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Markov Chain Monte Carlo (MCMC)
Polymer nanoparticles for drug and small silencing RNA delivery to treat cancers of different phenotypes
Authors: Devulapally Rammohan , Paulmurugan Ramasamy
Published: August 2013

Advances in nanotechnology have provided powerful and efficient tools in the development of cancer diagnosis and therapy. There are numerous nanocarriers that are currently approved for clinical use in cancer therapy. In recent years, biodegradable polymer nanoparticles have attracted a considerable attention for their ability to function as a possible carrier for target‐specific delivery of various drugs, genes, proteins, peptides, vaccines, and other biomolecules in humans without much toxicity. This review will specifically focus on the recent advances in polymer‐based nanocarriers for various drugs and small silencing RNA's loading and delivery to treat different types of cancer. WIREs Nanomed Nanobiotechnol 2014, 6:40–60. doi: 10.1002/wnan.1242

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease
Quarter-BPS AdS
5 solutions in M-theory with a T
2 bundle over a Riemann surface
Authors: Bah Ibrahima
Published: August 2013

Abstract

We study and classify quarter-BPS AdS
5 systems in M-theory, whose internal six-dimensional geometry is a T
2 bundle over a Riemann surface and two interval directions. The general system presented, provides a unified description of all known AdS
5 solutions in M-theory. These systems are governed by two functions, one that corresponds to the conformal factor of the Riemann surface and another that describes the T
2 fibration. We find a special set of solutions that can be organized into two classes. In the first one, solutions are specified by the conformal factor of the Riemann surface which satisfies a warped generalization of the SU(∞) Toda equation. The system in the second class requires the Riemann surface to be S
2, H
2 or T
2. Class one contains the M-theory AdS
5 solutions of Lin, Lunin and Maldacena; the solutions of Maldacena and Núñez; the solutions of Gauntlett, Martelli, Sparks and Waldram; and the eleven-dimensional uplift of the Y

p,q
metrics. The second includes the recently found solutions of Beem, Bobev, Wecht and the author. Within each class there are new solutions that will be studied in a companion paper.
Results and long-term patient satisfaction after gluteal augmentation with platelet-rich plasma-enriched autologous fat
Authors: Willemsen Joep C. N. , Lindenblatt Nicole , Stevens Hieronymus P. J. D.
Published: August 2013

Background

Buttock augmentation is gaining increasing popularity in aesthetic surgery. The relatively high incidence of complications after silicone implant placement lead to the increased use of lipofilling techniques, yielding variable results with respect to graft take rate and long-term stability. Platelet-rich plasma (PRP) has been shown to have beneficial effects on wound healing and angiogenesis in the past. Therefore, we aimed at investigating the long-term results and patient satisfaction after PRP-enriched lipofilling for buttock augmentation.

Methods

Twenty-four bilateral gluteal augmentations with PRP-enriched autologous fat were performed. Additionally, contour shaping was achieved by liposuction of the adjacent zones. Post-operative results and complications were recorded, and satisfaction with buttock shape was estimated by a patient questionnaire.

Results

Mean follow-up time was 44 months, and mean amount of transferred fat was 481 cc for both sides. No seroma or hematoma formation, infection or liponecrosis were reported during the post-operative follow-up. Subjective patient satisfaction in general increased from preoperatively to 3 months postoperatively and declined only slightly in the long-term course. Satisfaction levels in general were specific for each patient. Patient recovery was quick, and the majority of patients returned to work within 10 days after surgery.

Conclusions

PRP-enhanced lipofilling of the buttocks proved to be a safe procedure including a low complication rate and consistent results. However, subjective patient expectations have to be taken into account when choosing the indication. Further large volume studies are needed to elucidate the potential and benefit of PRP in this context.

Level of Evidence: Level IV, therapeutic study.
Asymptotic Normality for Inference on Multisample, High-Dimensional Mean Vectors Under Mild Conditions
Authors: Aoshima Makoto , Yata Kazuyoshi
Published: August 2013

In this paper, we consider the asymptotic normality for various inference problems on multisample and high-dimensional mean vectors. We verify that the asymptotic normality of concerned statistics is proved under mild conditions for high-dimensional data. We show that the asymptotic normality can be justified theoretically and numerically even for non-Gaussian data. We introduce the extended cross-data-matrix (ECDM) methodology to construct an unbiased estimator at a reasonable computational cost. With the help of the asymptotic normality, we show that the concerned statistics given by ECDM can ensure consistency properties for inference on multisample and high-dimensional mean vectors. We give several applications such as confidence regions for high-dimensional mean vectors, confidence intervals for the squared norm and the test of multisample mean vectors. We also provide sample size determination so as to satisfy prespecified accuracy on inference. Finally, we give several examples by using a microarray data set.
Achieving the Best Yield in Glycolipid Biosurfactant Preparation by Selecting the Proper Carbon/Nitrogen Ratio
Authors: Saikia Rashmi Rekha , Deka Hemen , Goswami Debahuti , Lahkar Jiumoni , Borah Siddhartha Narayan , Patowary Kaustuvmani , Baruah Plabita , Deka Suresh
Published: August 2013

Pseudomonas aeruginosa RS29, the native biosurfactant‐producing strain isolated from the oil fields of Assam, India was used to investigate the influence of the carbon nitrogen ratio on production of the biosurfactant. The biosurfactant producing ability of the strain was measured based on surface tension (ST) reduction of the culture medium and the emulsification (E24) index. Production was greatly influenced by the sources of nitrogen and carbon as well as the carbon to nitrogen (C/N) ratio. Sodium nitrate was the best nitrogen source and the water miscible carbon source, glycerol was observed as the best carbon source for maximum biosurfactant production. The C/N ratio 12.5 allowed the maximum production of biosurfactant by the RS29 strain. At this C/N ratio, 55 % ST of the culture medium was reduced by the produced biosurfactant. Concentrations of crude and rhamnolipid biosurfactant obtained at this particular C/N ratio were 5.6 and 0.8 g/l respectively. The RS29 strain was novel as it was able to produce a sufficient amount of biosurfactant utilizing a much lower amount of the water miscible carbon source, glycerol. Extraction of the biosurfactant by a chloroform–methanol (2:1) mixture was the best method to obtain the highest biosurfactant from the culture medium of the strain. The biosurfactant was confirmed as a mixture of mono and di‐rhamnolipid congeners, Rha–C10–C10–CH3 being the most abundant one. The biosurfactant was a good foaming and emulsifying agent.
Interaction of Light and Temperature on Tocopherols During Oxidation of Sunflower Oil
Authors: Choe Eunok
Published: August 2013

Light and temperature effects on tocopherols during the oxidation of sunflower oil were studied. The oxidation was performed at 40, 60, or 80 °C for 30, 15, and 6 days, respectively, in the dark or under 1,700 lux light. Oil oxidation was analyzed with peroxide values and conjugated dienoic acid contents, and tocopherols in the oil were separated and quantified by HPLC. The oxidation of sunflower oil was increased with temperature increase, and the light decreased the temperature dependence of the oil oxidation. Sunflower oil before oxidation contained tocopherols with a total of 737.96 mg/kg, with α‐ and γ‐tocopherol at 726.41 and 11.56 mg/kg, respectively, and the tocopherol contents decreased during the oil oxidation. Degradation of tocopherols increased with the temperature increase, and its dependence on the temperature was lower under light than in the dark. γ‐Tocopherol showed higher stability than α‐tocopherol during oxidation of the oil in the dark and under light. Residual amounts of tocopherols showed a relatively good correlation with the degree of oil oxidation, and the dependence of α‐tocopherol degradation on the oil oxidation was higher than that of γ‐tocopherol, and light decreased the dependence on the oil oxidation in both tocopherols.
Physicochemical Properties of Dry‐Heated Peanut Protein Isolate Conjugated with Dextran or Gum Arabic
Authors: Li Chen , Zhu Bo , Xue Haoran , Chen Zhiyan , Ding Qiao , Wang Xingguo
Published: August 2013

Peanut protein isolate (PPI) were conjugated with dextran or gum arabic through glycation to study the physiochemical properties of PPI–polysaccharides conjugates. Structural features, solubility as well as emulsifying properties of the two conjugates were compared. The degree of graft value of the two conjugates suggested that glycation of PPI with gum arabic took place more easily than with dextran. Glycated conjugates had better solubility and emulsifying ability than native PPI. Analysis of structural features of the conjugates suggested that their improved functional properties could be the result of less α‐helix secondary structure, lower surface hydrophobicity and less compact tertiary structure. The solubility of PPI–dextran conjugates was improved for the pH range 3–9, while that of PPI–gum arabic conjugates was improved above neutral pH range. Moreover, better emulsifying ability was observed in PPI–gum arabic conjugates than PPI–dextran conjugates.
Identification of Tetraacylglycerols in Lesquerella Oil by Electrospray Ionization Mass Spectrometry of the Lithium Adducts
Authors: Lin Jiann‐Tsyh , Chen Grace Q.
Published: August 2013

Tetraacylglycerol (an acylglycerol estolide) contains an acyl chain attached to the hydroxyl group of another acyl chain attached to the glycerol backbone. Lesquerolic acid (Ls, OH1420:111) is the main fatty acid in lesquerella oil and may be used industrially for the manufacture of biodegradable industrial products. Electrospray ionization mass spectrometry of the lithium adducts of acylglycerols in the high‐performance liquid chromatography fractions from the seed oil of lesquerella (Physaria fendleri) was used to identify thirteen tetraacylglycerols. They were LsLsLsLn, LsLsLsL, LsLs‐OH20:2‐O, LsLsLsO, LsLsLnLn, LsLsLLn, LsLsOLn, LsLsLL, LsLsOL, LsLsOP, LsLsOO, LsLsLS and LsLsOS. The OH20:2 was auricolic acid (OH1420:211,17). For the four tetraacylglycerols containing one normal fatty acid (non‐hydroxy fatty acid), LsLsLsLn, LsLsLsL, LsLs‐OH20:2‐O and LsLsLsO, the normal fatty acids were all directly attached to the glycerol backbone, not to the hydroxyl group of fatty acids. We propose that the biosynthetic precursors (triacylglycerol acyltransferase) of these four tetraacylglycerols were LsLsLn, LsLsL, LsLsO (Ls‐OH20:2‐O) and LsLsO individually. LsLsO and Ls‐OH20:2‐O were equally active as the biosynthetic precursors for LsLs‐OH20:2‐O. For LsLsLS, linoleate were all attached to the glycerol backbone and LsLsL was proposed to be the biosynthetic precursor. For LsLsOS, stearate were all attached to the glycerol backbone and LsLsS was proposed to be the biosynthetic precursor. For the other seven tetraacylglycerols containing two normal fatty acids, LsLsAB, the biosynthetic precursors could be both LsLsA and LsLsB.
Sperm DNA fragmentation assay by sperm chromatin dispersion (SCD): correlation between DNA fragmentation and outcome of intracytoplasmic sperm injection
Authors: Sivanarayana T. , Ravi Krishna Ch. , Jaya Prakash G. , Krishna K. M. , Madan K. , Sudhakar G. , Rama Raju G. A.
Published: August 2013

Purpose

The aim of the present study was to investigate the relationship between sperm DNA fragmentation index (sDFI) and outcome of intracytoplasmic sperm injection (ICSI).

Methods

All the patients were divided into two groups based on sperm DNA fragmentation analysis by the sperm chromatin dispersion (SCD) method. A total of 237 patients were in the DNA fragmentation normal group (sDFI ≤ 30 %), and 140 patients were in the DNA fragmentation abnormal group (sDFI ≥ 30 %). The relationship of sDFI with the outcome of ICSI was analyzed.

Results

A significant difference in semen parameters was observed between the DNA fragmentation normal and abnormal groups [count, motility and morphology (p < 0.05)]. However, no significant difference was seen between the number of oocytes retrieved and fertilization rates between the two groups, whereas the number of embryos progressed to day 3 and the blastocyst formation rate in the remaining embryos after transfer were significantly more in the DNA fragmentation normal group (p < 0.05). A significant negative correlation was noted between DFI values of more than 30 % and number of pregnancies and deliveries (p < 0.05). A higher DFI was also associated with increased abortion rates.

Conclusions

In the present study, sperm with DNA fragmentation showed a negative correlation with semen parameters. Further, sperm with damaged DNA have potential adverse effects on embryo progression, clinical pregnancy rate, and ongoing pregnancies.
Structure‐based protein‐protein interaction networks and drug design
Authors: Naveed Hammad , Han Jingdong J.
Published: August 2013

Proteins carry out their functions by interacting with other proteins and small molecules, forming a complex interaction network. In this review, we briefly introduce classical graph theory based protein‐protein interaction networks. We also describe the commonly used experimental methods to construct these networks, and the insights that can be gained from these networks. We then discuss the recent transition from graph theory based networks to structure based protein‐protein interaction networks and the advantages of the latter over the former, using two networks as examples. We further discuss the usefulness of structure based protein‐protein interaction networks for drug discovery, with a special emphasis on drug repositioning.
From homogenization to averaging in cellular flows
Authors: Ryzhik Lenya , Iyer Gautam , Komorowski Tomasz , Novikov Alexei
Published: August 2013

We consider an elliptic eigenvalue problem with a fast cellular flow of amplitude

A

, in a two-dimensional domain with

L^{2}

cells. For fixed

A

, and

L\rightarrow \infty

, the problem homogenizes, and has been well studied. Also well studied is the limit when

L

is fixed, and

A\rightarrow \infty

. In this case the solution equilibrates along stream lines.

In this paper, we show that if
both

A\rightarrow \infty

and

L\rightarrow \infty

, then a transition between the homogenization and averaging regimes occurs at

A \approx L^{4}

. When

A \gg L^{4}

, the principal Dirichlet eigenvalue is approximately constant. On the other hand, when

A \ll L^{4}

, the principal eigenvalue behaves like

\overline \sigma(A)/ L^{2}

, where

\overline \sigma(A) \approx \sqrt{A}I

is the effective diffusion matrix. A similar transition is observed for the solution of the exit time problem. The proof in the homogenization regime involves bounds on the second correctors. Miraculously, if the slow profile is quadratic, these estimates can be obtained using drift independent

L^{p}\rightarrow L^{\infty }

estimates for elliptic equations with an incompressible drift. This provides effective sub- and super-solutions for our problem.
Optimal treatment of hypothyroidism associated with live birth in cases of previous recurrent placental abruption and stillbirth
Authors: Vanes Neil K. , Charlesworth Dorreh , Imtiaz Rabia , Cox Philip , Kilby Mark D. , Chan Shiao Y.
Published: August 2013

Objective

To examine the clinical management of and placentas from pregnant women with hypothyroidism and obstetric history of recurrent stillbirth in order to identify possible etiologic mechanisms.

Methods

Two cases involving 26‐year‐old women with hypothyroidism and history of recurrent stillbirth are reported. Placentas from all of the women's pregnancies were compared in order to identify histologic similarities.

Results

In both cases, multifocal hemorrhagic infarctions and abruptions were seen, indicating progressive uteroplacental ischemic damage leading to stillbirth. Thrombophilia, infection, and diabetes tests were all negative. With meticulous monitoring and normalization of thyroid function by end of first/early second trimester in subsequent pregnancies, there were live births and no evidence of infarction on placental histology.

Conclusion

The 2 reported cases raise the possibility of uteroplacental ischemia and placental abruption being mechanisms by which hypothyroidism can lead to stillbirth; they also highlight the potential of minimizing this risk via adequate levothyroxine treatment from early pregnancy.
Persistent abdominal pain over uterine scar during labor as a predictor of delivery complications
Authors: Cohen Aviad , Cohen Yoni , Laskov Ido , Maslovitz Sharon , Lessing Joseph B. , Many Ariel
Published: August 2013

Objective

To evaluate the significance of persistent lower abdominal pain in women with previous cesarean delivery.

Methods

Various maternal outcomes were compared between women who underwent repeated cesareans owing to persistent lower abdominal pain (study group) and women who underwent repeated cesareans without persistent abdominal pain (control group).

Results

The incidence of uterine rupture was significantly higher in the study group than in the control group (8/81 [9.9%] vs 0/119 [0.0%]; P < 0.001). While all women with persistent lower abdominal pain and uterine rupture had an additional sign or symptom, only 6/73 (8.2%) women with persistent abdominal pain without uterine rupture had any additional symptoms (P < 0.001). There was no difference in incidence of uterine scar dehiscence between the groups. However, the hospitalization period was significantly longer in the study group (4 vs 3.7 days; P < 0.05). Trial of labor was a contributing factor to uterine rupture.

Conclusion

Isolated persistent lower abdominal pain in women with previous cesarean is a poor indicator of uterine rupture. However, the positive predictive value for uterine rupture is 57% when an additional sign or symptom is present. Dehiscence of the uterine scar is relatively common and it is not associated with persistent abdominal pain.
New WHO recommendations on prevention and treatment of postpartum hemorrhage
Authors: Tunçalp Özge , Souza João Paulo , Gülmezoglu Metin
Published: August 2013

Improving health care for women during childbirth in order to prevent and treat postpartum hemorrhage (PPH) is an essential step toward achieving Millennium Development Goal 5. In March 2012, WHO held a Technical Consultation on the Prevention and Treatment of Postpartum Haemorrhage to review current evidence and to update previously published PPH guidelines. The present paper provides an overview of the most recent WHO guidelines for both prevention and treatment of PPH, with an emphasis on the key messages and changes.
Employee Perception of a Mandated Helmet Policy at Vail Resorts
Authors: Davis Christopher B. , Brownson Mark R. , Levy Brent J. , Valley Morgan A. , Evans Bruce , Lowenstein Steven R.
Published: August 2013

Objective

The purpose of this study was to measure support for a mandated helmet policy among resort employees along with the impact of such a policy on job satisfaction, and additionally, to measure the prevalence of barriers to helmet use among this population.

Methods

In all, 728 Vail Resort employees were surveyed regarding their opinions on the helmet policy and on general helmet use.

Results

The majority of the 728 employees surveyed (66.5%; 95% CI: 63% to 70%) agreed with the helmet policy. Only 18% (95% CI: 16% to 21%) reported a negative effect on job satisfaction. Older employees (>25 years old) were more likely to disagree with the policy (odds ratio [OR] 3.1; 95% CI: 2.2 to 4.3) and report a negative effect on job satisfaction (OR 4.8; 95% CI: 3.0 to 7.6). Skiers were much more likely than snowboarders to report a negative effect on job satisfaction (OR 9.8; 95% CI: 5.2 to 18.1). Among resort employees, ski patrollers were more likely to disagree with the mandate (OR 9.8; 95% CI: 6.8 to 13.9) and report a negative effect on job satisfaction (OR 13.2; 95% CI: 8.3 to 21.). Forty-three percent of participants (95% CI: 39% to 46%) agreed with the statement that wearing a helmet encourages reckless behavior whereas 51.0% (95% CI: 47% to 54%) believed that wearing a helmet limits sensory perception.

Conclusions

A mandatory helmet use policy was supported by most resort employees. However, ski patrollers and older, more experienced employees were more likely to report a negative effect on job satisfaction. Barriers to helmet use continue to persist in the ski industry and represent a target for further educational efforts.
The flow of red blood cells through a narrow spleen-like slit
Authors: Freund Jonathan B.
Published: August 2013

Small slits between endothelial cells in the spleen are perhaps the smallest blood passages in the body, and red blood cells must deform significantly to pass through them. These slits have been posited to participate in the removal of senescent blood cells from the circulation, a key function of the spleen. One of the effects of red blood cell aging is an increased cytosol viscosity; relaxation time measurements suggest their interior viscosity can increase by up to a factor of 10 toward the end of their normal 120 day circulating lifetime. We employ a boundary integral model to simulate red blood cells as they deform sufficiently to flow through such a small passage, whether in the spleen or in a microfluidic device. Different flow rates and cytosol viscosities show three distinct behaviors. (1) For sufficiently slow flow, the pressure gradient is insufficient to overcome elastic resistance and the cell becomes jammed. (2) For faster flow, the cell passes the slit, though more slowly for higher cytosol viscosity. This can be hypothesized to facilitate recognition of senescent cells. (3) A surprising behavior is observed for high elastic capillary numbers, due either to high velocity or high cytosol viscosity. In this case, the cells infold within the slit, with a finger of low-viscosity plasma pushing deeply into the cell from its upstream side. Such infolding might provide an additional mechanism for jamming, and the sharpness of the resulting features would be expected to promote cell degradation. Linear analysis of a model system shows a similar instability, which is analyzed in regard to the cell flow. This linear analysis also suggests a similar instability for unphysiologically low cytosol viscosity. Simulations confirm that a similar infolding also occurs in this case, which intriguingly suggests that normal cytosol viscosities are in a range that is protective against such deformations.
A mechanism for unsteady separation in over-expanded nozzle flow
Authors: Olson Britton J. , Lele Sanjiva K.
Published: August 2013

Shock wave induced separation in an over-expanded planar nozzle is studied through numerical simulation. These Large-Eddy Simulations (LES) model previous experiments which have shown unsteady motion of the shock wave in flows with similar geometries but offered little insight into the underlying mechanism. Unsteady separation in nozzle flow leads to “side loads” in the rocket engine which can adversely affect the stability of the rocket. A mechanism for the low-frequency shock motion is identified and explained using the LES data. This mechanism is analyzed for a series of over-expanded planar nozzles of various area ratios and nozzle pressure ratios. The effect of grid resolution and Reynolds number on the instability is discussed. A simple reduced order model for the unsteady shock behavior is used to further validate the proposed mechanism. This model is derived from first principles and uses data from the LES calculations to capture the effects of the turbulent boundary layer and shear layer.
Experimental study of spectral energy fluxes in turbulence generated by a fractal, tree-like object
Authors: Bai Kunlun , Meneveau Charles , Katz Joseph
Published: August 2013

We report on an experimental study of the kinetic energy fluxes between scales in the turbulent near-wake flow downstream of a fractal, tree-like object. Experiments are performed in a liquid channel and data are acquired using planar Particle Image Velocimetry (PIV). The data are analyzed based on the filtering framework of relevance to Large Eddy Simulations. The flow and energy fluxes differ from the case of a canonical flow such as the cylinder wake, where typically kinetic energy is injected into turbulence by an object characterized by a single, well-defined, length-scale. For a fractal tree-like object, we find that the measured energy flux is strongly dependent on scale. In the present flow, scale-dependent injection of kinetic energy into the cascade arises from production as well as spatial transport terms. The injection rate spectrum is evaluated directly from the data by quantifying the rate of change of spectral energy flux as a function of wavenumber. The net injection rate spectrum is observed to scale approximately as ∼k−7/3, in accordance with heuristic and dimensional arguments previously used for the kinetic energy production rate spectrum in shear flows. In order to scale the results, we consider an equivalent mixing length-scale that can be obtained from the tree geometry by adding over the relevant scales of successive branch clusters. In prior work, this equivalent length scale has been found to collapse the eddy-viscosity well. Here we find that this scale also collapses the energy flux and the net injection rate spectrum successfully.
Intermittency of intermittencies
Authors: Hramov Alexander E. , Koronovskii Alexey A. , Moskalenko Olga I. , Zhuravlev Maxim O. , Ponomarenko Vladimir I. , Prokhorov Mikhail D.
Published: August 2013

A phenomenon of intermittency of intermittencies is discovered in the temporal behavior of two coupled complex systems. We observe for the first time the coexistence of two types of intermittent behavior taking place simultaneously near the boundary of the synchronization regime of coupled chaotic oscillators. This phenomenon is found both in the numerical and physiological experiments. The laws for both the distribution and mean length of laminar phases versus the control parameter values are analytically deduced. A very good agreement between the theoretical results and simulation is shown.
Reversal of spiral waves in an oscillatory system caused by an inhomogeneity
Authors: Li Teng-Chao , Li Bing-Wei
Published: August 2013

Spatial heterogeneities are commonly found in realistic systems and play significant roles in dynamics of spiral waves. We here demonstrate a novel phenomenon that a localized inhomogeneity put around the spiral core could lead to the reversal of spiral waves in an oscillatory system, e.g., the complex Ginzburg-Landau equation. With the amplitude-phase representation, we analyze underling mechanism and conditions of the wave reversal in detail, which is found to agree with the numerical evidence.
A photonic crystal sets a peculiar trap
Authors: Smart Ashley G.
Published: August 2013

Even for light that’s energetic enough to escape the device, destructive interference can get in the way.
Weighing exotic calcium isotopes
Authors: Schwarzschild Bertram M.
Published: August 2013

The binding energies of nuclei with far too many neutrons reveal new nuclear structure.
Smart cities will need big data
Authors: Kramer David
Published: August 2013

A new academic center in New York City joins other efforts to harness data from disparate sources with the goal of improving city life.
US nano thrust tilts toward technology transfer
Authors: Feder Toni
Published: August 2013

Nanoscience may be poised to deliver on its promises of adaptive materials and smart systems in manufacturing, energy, medicine, and more.
Globetrotting summer “camp” aims to fuse condensed matter and culture
Authors: Matthews Jermey N. A.
Published: August 2013

The world tour could end in 2014, when NSF pulls support for a program that promotes collaboration between US materials scientists and their international counterparts.
Wall-bounded turbulence
Authors: Smits Alexander J. , Marusic Ivan
Published: August 2013

New experimental insights could pave the way for leaner, faster simulations of turbulent fluid flow.
Santa Barbara, physics, and the long 1970s
Authors: Mody Cyrus C. M.
Published: August 2013

The adaptations of a group of Southern California physicists to the trying conditions of the 1970s anticipated some of the important 21st-century trends in the discipline.