bluuebunny/crossref_metadata_2025_split huggingface dataset:
Olympic Gels: Concatenation and Swelling
Authors: Lang Michael , Fischer Jakob , Werner Marco , Sommer Jens‐Uwe 
Published: December 2015

SummaryConcatenation and equilibrium swelling of Olympic gels, which are composed of entangled cyclic polymers, is studied under athermal conditions with Monte‐Carlo simulations. The average number of concatenated molecules per cyclic polymer,fn, is found to depend on the degree of polymerization,N, and polymer volume fraction at network preparation,, aswith scaling exponentv = 0.588. In contrast to chemically cross‐linked polymer networks, we observe that Olympic gels made of longer cyclic chains exhibit a smaller equilibrium swelling degree,, at the same polymer volume fraction. This observation is explained by a des‐interspersion process of overlapping non‐concatenated rings upon swelling, which is tested directly by analyzing the change in overlap of the molecules upon swelling.
Effect of Constraints on Swelling of Polymer Networks
Authors: Dušek Karel , Dušková‐Smrčková Miroslava , Šomvársky Ján 
Published: December 2015

SummarySwelling of cross‐linked polymer constructs in which swelling of network is constrained by adhering rigid substrate or another cross‐linked polymer (coatings, core‐shell particles, and particulate composites of rigid filler in cross‐linked matrix) is investigated. The equilibrium state was modeled analytically or by the Finite Element Method. A Gibbs energy function was selected which respects the finite extensibility of network chains. Also, the additive contribution to the Gibbs energy of swollen systems due to mixing was reformulated. The mixing of cross‐linked polymer with solvent is considered without deforming the network chains, instead of mixing of solvent with an infinite uncross‐linked polymer molecule.
Click Chemistry in Materials Synthesis: The Beginning
Authors: Díaz Díaz David 
Published: December 2015

SummaryThe transition from the early applications of click chemistry in organic synthesis and biotechnology to materials synthesis was profoundly marked by the pioneering preparation of metal‐adhesive polymers based on the copper (I)‐catalyzed cycloaddition reaction between azides and alkynes. Herein, it is summarized a fascinating journey from the original discovery, made more than a decade ago, until the recent development of high‐strength electrically conductive adhesives.
Synergistic Chemomechanical Oscillators: Periodic Gel Actuators without Oscillatory Chemical Reaction
Authors: Horváth Judit 
Published: December 2015

SummarySynergistic chemomechanical oscillators fundamentally differ from BZ‐gels or ordinary pH‐actuators where oscillatory chemical reactions are required as (internal) “frequency generators”. Periodicity can arise from the interplay between a non‐periodic but nonlinear chemical reaction (e.g., a “pH‐switch”) and a geometrical feedback that modifies the transport time of species between the gel core and the environment. The experimental realization of several different such systems is essential to identify their universal properties. To be operational, the fine tuning of the gel's pH‐response to the region of the pH‐drop in a particular chemical reaction turned out to be an essential step. Simultaneously, the weak acid functional groups present in the gel modify the pH‐drop range, and this also needs to be considered. Analogous interdependence between chemical and physical actions is believed to be an underlying mechanism in primary biological processes.
Interaction of Cartilage Biopolymers
Authors: Horkay Ferenc 
Published: December 2015

SummaryAggrecan is a charged biopolymer whose complexes with hyaluronic acid provide the compressive resistance of cartilage. In cartilage extracellular matrix aggrecan‐hyaluronic acid complexes are enmeshed within a network of collagen fibrils. Osmotic pressure measurements and small angle neutron scattering (SANS) measurements are reported on solutions of aggrecan and aggrecan‐hyaluronic acid complexes. These techniques probe the length scales relevant to the biological functions of cartilage. Osmotic pressure measurements indicate that dissolved aggrecan monomers form microgel‐like assemblies. The osmotic pressure of aggrecan‐hyaluronic acid complexes decreases with decreasing the ratio of aggrecan to hyaluronic acid. SANS reveals that there is no significant interpenetration between the neighboring aggrecan molecules. Both osmotic pressure measurements and SANS indicate weak interactions between the aggrecan bottlebrushes and collagen fibers.
Self‐Healing Poly(acrylic acid) Hydrogels: Effect of Surfactant
Authors: Gulyuz Umit , Okay Oguz 
Published: December 2015

SummaryPhysical poly(acrylic acid) gels were prepared by micellar copolymerization of hydrophilic monomer acrylic acid with large hydrophobic monomer stearyl methacrylate (C18) in solutions of worm‐like anionic surfactant (sodium dodecyl sulfate, SDS) and cationic surfactant (cetyltrimethyl ammonium bromide, CTAB) micelles. Hydrophobe content of the monomer mixtures was 2 mol.% and total monomer concentration in gels was 20 w/v%. Gelation reactions were monitored by rheometry using oscillatory deformation tests. Hydrogel samples were also subjected to uniaxial elongation and compression tests after preparation and swelling. The physical gels with SDS and CTAB showed similar properties as long as they are at the state of preparation, such as insoluble in water and exhibit time‐dependent dynamic moduli, high Young's modulus, high fracture stress, high elongation ratios at break. Also self‐healing was evidenced by mechanical measurements. Physical gels formed in SDS solution were stable, exhibited high equilibrium swelling ratios and SDS progressively extracted from the network in water. On the other hand, gels with CTAB formed a complex and resulted in shrinkage after gels were immersed in a large excess of water because both electrostatic interactions between the charged components and hydrophobic interactions between the polymer backbone and the alkyl chains of the surfactant are important in driving the self‐assembly of molecules to form ordered structures. These structures of the polyelectrolyte surfactant complexes have unusual mechanical properties. Also, the hydrogel samples with CTAB self‐healed via heating and surfactant treatment of the damaged areas withstand up to 1.05 MPa stresses and rupture at a stretch of 800%.
Characterization of the Secondary Structure of CP30, a Highly Repetitive Ampholytic Protein in Beetle Elytral Cuticle
Authors: Sprouse Patricia A. , Dittmer Neal T. , Kramer Karl J. , Kanost Michael R. , Dhar Prajnaparamita , Gehrke Stevin H. 
Published: December 2015

SummaryCP30 is a major component protein in the rigid cuticle of the beetle elytron which we recently identified. It has a highly unusual amino acid sequence comprised largely of alternating blocks of 3–5 anionic and cationic amino acid residues (three charged residues, glutamic acid, arginine and histidine, make up 76% of the sequence) which suggest an unusual stuctural role. The secondary structure of CP30 was evaluated at a variety of pH, ionic strength and temperature conditions. Circular dichroism (CD), fluorescence spectroscopy and static and dynamic light scattering showed that the protein had an extended α‐helical structure at pH 3, 5 and 7 which unfolded around 60°C and reformed upon cooling back to 10°C. The protein aggregated or adhered to the dialysis membrane at pH 5, low salt, which is close to the protein's isoelectric point (5.82), preventing analysis at that condition. Further studies aimed at solubilizing the protein near that condition may uncover evidence of assembly. While the structural function of CP30 is currently unknown, the sequence of CP30 may offer new design motifs for the development of novel polymer or gel biomaterials.
Structurally Versatile Glycosaminoglycan Hydrogels for Biomedical Applications
Authors: Khanlari Anahita , Suekama Tiffany C. , Gehrke Stevin H. 
Published: December 2015

SummaryDespite widespread use of hydrogels in biomedical devices, low moduli and brittleness of hydrogels has hindered applications with load bearing requirements. In this study, different molecular network design strategies (homopolymer, copolymer, and double network) were used to control the arrangement of macromers to tune the mechanical properties of glycosaminoglycan (GAG)‐based hydrogels. The resulting changes in swelling ratio, crosslink density, and fracture properties of the gels were then investigated. It was hypothesized that increasing the number of polymerizable groups on the macromers methacrylated chondroitin sulfate (MCS) or methacrylated hyaluronic acid (MHA) and using oligo(ethylene glycol diacrylate) s to copolymerize with can improve the crosslinking by increasing the effectiveness of polymerization through the kinetic chains. By increasing the degree of methacrylation of MCS from 24 to 34 mol%, the swelling ratio q and the crosslink density ρx of 13 wt% MCS gel was changed from 210 to 44 g/g and from 230 to 740 mol/m3, respectively. Despite improved ρx and tuned q, the fracture strain of the homo‐ and copolymer gels remained fairly low (<25%), likely due to the highly extended conformation of glycosaminoglycans, and the microheterogeneity induced by the kinetic chains. However, using a DN double network design (with PAAm), the fracture strain and toughness of the gels were greatly improved as the fracture strain of 15 wt% MCS‐PAAm DN increased more than 3 times, from 15 to 55%. The versatile physical and favorable biological properties of GAG‐based hydrogels make them promising materials for many biomedical applications.
Rapid label‐free profiling of oral cancer biomarker proteins using nano‐UPLC‐Q‐TOF ion mobility mass spectrometry
Authors: Nassar Ala. F. , Williams Brad J. , Yaworksy Dustin C. , Patel Vyomesh , Rusling James F. 
Published: December 2015

PurposeIt has become quite clear that single cancer biomarkers cannot in general provide high sensitivity and specificity for reliable clinical cancer diagnostics. This paper explores the feasibility of rapid detection of multiple biomarker proteins in model oral cancer samples using label‐free protein relative quantitation.Experimental designMS‐based label‐free quantitative proteomics offer a rapid alternative that bypasses the need for stable isotope containing compounds to chemically bind and label proteins. Total protein content in oral cancer cell culture conditioned media was precipitated, subjected to proteolytic digestion, and then analyzed using a nano‐UPLC (where UPLC is ultra‐performance liquid chromatography) coupled to a hybrid Q‐Tof ion‐mobility mass spectrometry (MS).ResultsRapid, simultaneous identification and quantification of multiple possible cancer biomarker proteins was achieved. In a comparative study between cancer and noncancer samples, approximately 952 proteins were identified using a high‐throughput 1D ion mobility assisted data independent acquisition (IM‐DIA) approach. As we previously demonstrated that interleukin‐8 (IL‐8) and vascular endothelial growth factor A (VEGF‐A) were readily detected in oral cancer cell conditioned media1, we targeted these biomarker proteins to validate our approach. Target biomarker protein IL‐8 was found between 3.5 and 8.8 fmol, while VEGF‐A was found at 1.45 fmol in the cancer cell media.Conclusions and clinical relevanceOverall, our data suggest that the nano‐UPLC‐IM‐DIA bioassay is a feasible approach to identify and quantify proteins in complex samples without the need for stable isotope labeling. These results have significant implications for rapid tumor diagnostics and prognostics by monitoring proteins such as IL‐8 and VEGF‐A implicated in cancer development and progression. The analysis in tissue or plasma is not possible at this time, but the subsequent work would be needed for validation.
Toxicity to Diaphania hyalinata, selectivity to non‐target species and phytotoxicity of furanones and phthalide analogues
Authors: Resende Gabriela C , Alvarenga Elson S , de Araújo Tamíris A , Campos Júlia ND , Pincanço Marcelo C 
Published: December 2015

AbstractBACKGROUNDDespite being of great importance to crop protection, the disadvantages of intensive and inappropriate use of pesticides have stimulated the search for more selective and less harmful agrochemicals. Thus, we have evaluated the effectiveness of 16 synthetic molecules (phthalides and precursors) to control the melonworm Diaphania hyalinata, a key pest in cucurbit crops of economic importance in Brazil. The selectivity to beneficial organisms Solenopsis saevissima and Tetragonisca angustula and the phytotoxicity to Cucumis sativus of the promising insecticides were also assessed.RESULTSIn the screening assay, compounds 1 and 6 provided 91 and 88% mortality of the melonworm. Compound 1 presented higher toxicity (median lethal dose LD50 = 15.99 µmol g−1) and higher speed on pest control (median survival time LT50 = 420 min) than compound 6 (LD50 = 44.51 µmol g−1 and LT50 = 840 min). Both compounds inhibited less than 11% of host‐plant growth and caused ≤36 and ≥93% mortality of predator and pollinator respectively.CONCLUSIONAmong the tested compounds, only compounds 1 and 6 were effective in melonworm control. Both compounds presented no considerable phytotoxicity and were selective to predator but non‐selective to pollinator, which enables their application for pest control if the exposure of the bees is minimised. © 2015 Society of Chemical Industry
Pancreatic enucleation using the da Vinci robotic surgical system: a report of 26 cases
Authors: Shi Yusheng , Peng Chenghong , Shen Baiyong , Deng Xiaxing , Jin Jiabin , Wu Zhichong , Zhan Qian , Li Hongwei 
Published: December 2015

AbstractBackgroundAs a tissue‐sparing procedure, pancreatic enucleation has become an alternative for benign or borderline pancreatic tumours; it has been proved to be safe and feasible. To date, a large sample size of robotic pancreatic enucleation has not been reported. This study aimed to discuss the clinical evaluation and postoperative complications after robotic pancreatic enucleation and compare it with open surgery.MethodsPatients who underwent robotic or open pancreatic enucleation during December 2010–December 2014 at Shanghai Ruijin Hospital, affiliated with the Shanghai Jiaotong University School of Medicine in China, were included. Clinical data were collected and analysed.ResultsPatients were divided into an open group and a robotic group: 26 patients underwent robotic pancreatic enucleation, of whom 13 patients were female. The mean age was 51.7 years, the operation time was 125.7 ± 58.8 min, blood loss was 49.4 ± 33.4 ml and mean tumour size was 18.8 ± 7.9 mm; 17 patients underwent open pancreatic enucleation, of whom 11 were female. The mean age was 54.6 ± 17.2 min, blood loss was 198.5 ± 70.7 ml and mean tumour size was 3.5 ± 1.9 cm. Pathology included insulinomas, intrapancreatic mucinous neoplasmas (IPMNs), pancreatic neuro‐endocrine tumours (PNETs), solid pseudopapillary tumours (SPTs) and serous cystadenomas (SCAs). Robotic pancreatic enucleations were associated with less trauma, shorter operation time, less blood loss and faster wound recovery compared with open pancreatic enucleation. Pancreatic fistulas (PFs) were the main complication that occurred in the robotic group; infection also occurred in the open group. All patients recovered after effective drainage and the use of somatostatin. The mean follow‐up time was 25 months. No recurrence was discovered, and one patient in the open group suffered endocrine insufficiency.ConclusionRobotic pancreatic enucleation is a safe and effective surgical procedure for pancreatic benign and borderline tumours. It produces less trauma than open pancreatic enucleation and might extend the indications for enucleation. The PF rate after surgery is still high and a long‐term follow‐up needs to be performed. Copyright © 2015 John Wiley & Sons, Ltd.
When is cash good or bad for firm performance?
Authors: Deb Palash , David Parthiban , O'Brien Jonathan 
Published: December 2015

Research summary: Cash can create shareholder value when used for adaptation to unfolding contingencies, but can also reduce value when appropriated by other stakeholders. We synthesize arguments from the behavioral theory of the firm, economic perspectives like agency theory, and the value‐creation versus value‐appropriation literatures to argue that the implications of cash for firm performance are context‐specific. Cash is more beneficial for firms operating in highly competitive, research‐intensive, or growth‐focused industries that are typical of contexts requiring adaptation in the face of uncertainties. Conversely, cash is more detrimental to performance in firms that are poorly governed, diversified, or opaque, as are typical of contexts where stakeholder conflicts, information asymmetries, or power imbalances can encourage value appropriation by other stakeholders.Managerial summary: Cash can create shareholder value when used for adaptation to unfolding contingencies, but can also reduce value when appropriated by other stakeholders. While cash‐rich firms have higher performance on average, with those in the 75th percentile having a market‐to‐book value 15 percent higher than those in the 25th percentile, we find that the performance benefits of cash depend on the context. Cash is more beneficial for firms operating in highly competitive, research‐intensive, or growth‐focused industries that are typical of contexts requiring adaptation in the face of uncertainties. Conversely, cash is more detrimental to performance in firms that are poorly governed, diversified, or opaque, as are typical of contexts where stakeholder conflicts, information asymmetries, or power imbalances can encourage value appropriation by other stakeholders. Copyright © 2015 John Wiley & Sons, Ltd.
Organizing for knowledge generation: internal knowledge networks and the contingent effect of external knowledge sourcing
Authors: Grigoriou Konstantinos , Rothaermel Frank T. 
Published: December 2015

Research summary: When faced with a new technological paradigm, incumbent firms can opt for internal development and/or external sourcing to obtain the necessary new knowledge. We explain how the effectiveness of external knowledge sourcing depends on the properties of internal knowledge production. We apply a social network lens to delineate interpersonal, intra‐firm knowledge networks and capture the emergence of two important firm‐level properties: the incumbent's internal potential for knowledge recombination and the level of knowledge coordination costs. We rely on firm‐level internal knowledge networks to dynamically track the emergence of these properties across 106 global pharmaceutical companies over a 25‐year time period. We find that a firm's success in developing knowledge in a new technological paradigm using external knowledge sourcing is contingent on these internal knowledge properties.Managerial summary: Incumbent firms in high‐tech industries often face competence‐destroying technological change. In their effort to adapt and develop new knowledge in a novel paradigm, incumbent firms have several corporate strategy options available to them: internal knowledge development and a wide array of external knowledge sourcing strategies, including alliances and acquisitions. In this study, we make an effort to address a critical question: How effective is external knowledge sourcing under different internal knowledge generation regimes? We find that external sourcing strategies are less effective when firms can already internally generate new knowledge or if they have high internal coordination costs. Therefore, when considering external sourcing, managers must carefully weigh the benefits of it vis‐à‐vis its commensurate costs as the benefits of external sourcing may be overstated. Copyright © 2015 John Wiley & Sons, Ltd.
Balance the wind power generation and transmission—case study in China
Authors: Song Yanqin 
Published: December 2015

AbstractIn most places in the world, the load center and the best wind resources are located far away from each other. Therefore, electricity generated from wind farms has to be transmitted to the load center over lengthy transmission lines. However, in some cases, lower quality wind resources also available close to load centers. Therefore, decision makers are sometime faced with competing alternatives: building wind farms in areas with higher wind speeds far away from load centers and or building wind farms in areas with lower wind speeds close to load centers. This paper proposes a methodology to help policy makers to develop wind resources cost effectively, balancing wind power generation from best wind resources and transmission of electricity over long distance. The methodology is applied to China, to compare development of high‐quality wind resources in the Three‐North region (north, northwest and northeast) and transmission of electricity to Southeast load centers to the development of lower quality resources closer to the same load centers. The results would help decision makers at the national and provincial levels to optimally develop the country's resources and assess the benefits of renewable energy trade between provinces. Copyright © 2015 John Wiley & Sons, Ltd.
Unraveling the mechanistic complexity of Alzheimer's disease through systems biology
Authors: Rollo Jennifer L. , Banihashemi Nahid , Vafaee Fatemeh , Crawford John W. , Kuncic Zdenka , Holsinger R.M. Damian 
Published: December 2015

AbstractAlzheimer's disease (AD) is a complex, multifactorial disease that has reached global epidemic proportions. The challenge remains to fully identify its underlying molecular mechanisms that will enable development of accurate diagnostic tools and therapeutics. Conventional experimental approaches that target individual or small sets of genes or proteins may overlook important parts of the regulatory network, which limits the opportunity of identifying multitarget interventions. Our perspective is that a more complete insight into potential treatment options for AD will only be made possible through studying the disease as a system. We propose an integrative systems biology approach that we argue has been largely untapped in AD research. We present key publications to demonstrate the value of this approach and discuss the potential to intensify research efforts in AD through transdisciplinary collaboration. We highlight challenges and opportunities for significant breakthroughs that could be made if a systems biology approach is fully exploited.