bluuebunny/crossref_metadata_2025 huggingface dataset:
Examining Firm Value Drivers: An Empirical Analysis of Property and Real Estate Companies on the Indonesian Stock Exchange
Authors: Sulistiyo Heru , Sitawati Riana , Sutono . , Sudarman .
Published: May 2024

Aims: This study aims to investigate the impact of company size, leverage, and profitability on firm value using the price-to-book value (PBV) ratio as a proxy, focusing on property and real estate businesses listed on the Indonesia Stock Exchange (IDX).
Study Design:  The research adopts a correlational study design.
Place and Duration of Study: Indonesian Stock Exchange (IDX) issuers in 2021-2022.
Methodology: The study was conducted using data from Indonesian Stock Exchange (IDX) issuers during the years 2021-2022.The population comprised property and real estate businesses listed on the IDX, totaling 161 companies (76 in 2021 and 85 in 2022). The sample was determined through a census method, resulting in 123 valid samples after excluding 38 outlier data points identified through a normality test. Data collection was conducted through documentation, and analysis was performed using multiple linear regression in SPSS 24.
Results: The research findings indicate that company size, leverage, and profitability have a significant positive influence on firm value.
Conclusion: The study's results provide empirical support for signaling theory, demonstrating that enhancements in company size, leverage, and profitability positively impact firm value.
Optimizing Tomato Health: Holistic Approach to Early Blight Disease Management
Authors: P. D Dole , S. D Gaikwad , Digvijay Chavan
Published: May 2024

An experiment was conducted to evaluate the effect of fungicide (mancozeb) and botanicals against early blight of tomato caused by Alternaria solani at the experimental field and glasshouse of Plant Pathology department, College of Agriculture, Pune, Maharashtra, during Kharif season (2019-2020). Six treatments including control with four replications were taken up using Randomized Block Design RBD. Growth inhibition of fungus Alternaria solani causing early leaf blight of tomato was studied in vivo for determining the efficacy of one fungicide and eight botanicals. Exploring possibility of managing A. solani by use of botanicals revealed that the clove extract of garlic was the best followed by neem leaf and ginger rhizome extract showing highest growth inhibition of the fungus. Among the plant leaf extracts, garlic clove extract @10% was found effective to inhibit the growth of pathogen i.e. 64.60% Per cent disease control PDC (glasshouse trial) and 51.85% PDC (open Field trial). The contact fungicide Mancozeb@0.25% showed disease control of 75.52% (Glasshouse trial) and PDC of 70.34% (Field trial) in in vivo condition. Presently many farmers are using chemicals for control of early blight of tomato however, they cause health hazards. Therefore, this investigation provides valuable insights for farmers in selecting suitable plant extracts to control early blight of tomatoes.
Strengthening Corporate Cash Holdings and Investment Efficiency in the COVID-19 Pandemic: Some Empirical Evidence from Indonesia Emerging Markets
Authors: Cahyono Suham , Ardianto Ardianto
Published: May 2024

This study explores the connection between the amount of cash a company holds and its effectiveness in making investments, as well as the effect of the COVID-19 pandemic. The researchers analyzed a dataset consisting of 2721 observations from Indonesian publicly listed firms between 2013 and 2020, excluding the financial industry (SIC 6). They utilized multiple linear regression analysis to investigate how cash holding influences investment efficiency and how the COVID-19 pandemic affects this relationship. The research approach employed was quantitative. The results indicate that a higher cash holding has a negative impact on investment efficiency. The uncertainty caused by the COVID-19 outbreak has significantly affected corporate cash flows, impeding business activities. Additionally, robustness tests were conducted to address concerns regarding potential bias, and the results consistently aligned with the ordinary least squares (OLS) estimation. These findings are significant for investors, potential investors, and management, providing insights into the interplay among cash holding, investment efficiency, and the COVID-19 Pandemic.
Production and Titration of Lentiviral Vectors
Authors: Barde Isabelle , Salmon Patrick , Trono Didier
Published: October 2010

Lentiviral vectors have emerged over the last decade as powerful, reliable, and safe tools for stable gene transfer in a wide variety of mammalian cells. Unlike other vectors derived from oncoretroviruses, they allow for stable gene delivery into most nondividing primary cells, including neurons. This is why lentivectors (LVs) are becoming the most useful and promising tools in the field of neuroscience, not only for research, but also for future gene and cell therapy approaches. LVs derived from HIV‐1 have gradually evolved to display many desirable features aimed at increasing both their safety and their versatility. These latest designs are reviewed in this unit. This unit also describes protocols for production and titration of LVs that can be implemented in a research laboratory setting, with an emphasis on standardization to improve transposability of results between laboratories. Curr. Protoc. Neurosci. 53:4.21.1‐4.21.23. © 2010 by John Wiley & Sons, Inc.
Multi‐Photon Imaging
Authors: Padmanabhan Krishnan , Andrews Shane E. , Fitzpatrick James. A.J.
Published: October 2010

Multi‐photon microscopy, now in its twentieth year, has developed into one of the most robust and powerful techniques for live cell and in vivo fluorescence imaging. Although its theoretical framework is nearly a century old, it has only become a practical tool for biological research with the development of ultrafast lasers and scanning microscopy techniques. In this unit, we outline the basic principles of multi‐photon microscopy, paying special attention to technical considerations for biological applications. Furthermore, we discuss some common applications of the technique, mainly in the field of live cell and in vivo imaging. We illustrate how multi‐photon microscopy can be utilized to address questions ranging from structural cell changes to trafficking of membrane proteins in living organisms, often with resolutions of hundreds of milliseconds. We conclude by outlining the necessary elements needed to establish a successful two‐photon microscopy system. Curr. Protoc. Cytom. 54:2.9.1‐2.9.12. © 2010 by John Wiley & Sons, Inc.
Phenotypic Analysis Using Very Small Volumes of Blood
Authors: Weaver James L. , McKinnon Katherine , Germolec Dori R.
Published: October 2010

Analysis of cell‐surface phenotype of peripheral blood leukocytes is one of the most common applications of flow cytometry. In mouse research, the small size of the animal limits the amount of blood available. Standard staining methods using lysis of erythrocytes or gradient separation followed by repeated washing involve unavoidable losses of cells that generally limit analysis of blood to terminal methods. Time‐course studies, therefore, require sacrifice of groups of mice at each time point. Thus, a method is needed that can be used with much smaller volumes of blood. This will allow serial sampling of the same animal over time, decreasing experimental variability and reducing animal use. The method described here is a no‐lyse, no‐wash method that uses triggering on a fluorescence parameter. The method allows routine analysis of the phenotype of peripheral blood leukocytes using whole‐blood volumes of 20 µl per tube. The data are comparable with values from traditional methods requiring much higher volumes of blood. Due to interference by erythrocytes, light‐scatter parameters are not usable with this method. This method has been used for time‐course studies of peripheral blood populations in mice lasting as long as four weeks. Curr. Protoc. Cytom. 54:6.30.1‐6.30.8. © 2010 by John Wiley & Sons, Inc.
From Image to Data Using Common Image‐Processing Techniques
Authors: Sysko Laura R. , Davis Michael A.
Published: October 2010

A digital microscopy image is an array of number values, which with adequate contrast can be interpreted as spatial information. Through processing and analysis by mathematical means, using computer‐assisted imaging software programs, raw image data contrast can be enhanced to improve the extraction of image features for measurement and analysis. This mathematical feature extraction (referred to as segmentation) provides the basis for general image processing. The methods discussed in this unit address common image analysis challenges such as object counting with touching objects, objects within other objects, and object identification in a field with uneven illumination or uneven brightness, along with step‐by‐step procedures for achieving these results. Curr. Protoc. Cytom. 54:12.21.1‐12.21.17. © 2010 by John Wiley & Sons, Inc.
Density and microhabitat use of Bengal slow loris in primary forest and non‐native plantation forest
Authors: Pliosungnoen Manoon , Gale George , Savini Tommaso
Published: October 2010

The extent of planted forests has greatly increased in the tropics, but their conservation value while assumed to be low, is largely unknown. We compared the density and microhabitat selection of a nocturnal arboreal primate, the Bengal slow loris (Nycticebus bengalensis), in mostly undisturbed, evergreen tropical forest to those in 15–18 year old Acacia/Leucaena plantations with significant secondary regrowth, and <15 year old plantations with little regrowth. Based on estimates derived from distance sampling, loris densities in older plantations were nearly identical to primary forest (4.26 vs. 4.00 lorises per square kilometer), although encounter rates were three times higher in the older plantations probably owing to the lower detection probability in the more complex vegetation of the primary forest. The mean density estimate for the younger plantation was one‐third of the above habitats (1.27 lorises per square kilometer), although not statistically different. Lorises tended to use larger diameter and taller trees, with a greater crown depth than randomly sampled trees, and tended to avoid habitats with sparsely crowned trees. The older plantations had trees with lower basal area and shorter stems than the primary forest; however, the older plantations contained higher densities of Bauhinia lianas, a commonly eaten food source and did not contain the red giant flying squirrel (Petaurista petaurista), a potential competitor. Although it is unknown whether the Bengal slow loris would persist without the presence of primary forest in the landscape, we suggest that older plantations have conservation value for at least selected species and as such, could be better managed to increase this value. Am. J. Primatol. 72:1108–1117, 2010. © 2010 Wiley‐Liss, Inc.
Characterization of opsin gene alleles affecting color vision in a wild population of titi monkeys (Callicebus brunneus)
Authors: Bunce John A. , Isbell Lynne A. , Neitz Maureen , Bonci Daniela , Surridge Alison K. , Jacobs Gerald H. , Smith David Glenn
Published: October 2010

The color vision of most platyrrhine primates is determined by alleles at the polymorphic X‐linked locus coding for the opsin responsible for the middle‐ to long‐wavelength (M/L) cone photopigment. Females who are heterozygous at the locus have trichromatic vision, whereas homozygous females and all males are dichromatic. This study characterized the opsin alleles in a wild population of the socially monogamous platyrrhine monkey Callicebus brunneus (the brown titi monkey), a primate that an earlier study suggests may possess an unusual number of alleles at this locus and thus may be a subject of special interest in the study of primate color vision. Direct sequencing of regions of the M/L opsin gene using feces‐, blood‐, and saliva‐derived DNA obtained from 14 individuals yielded evidence for the presence of three functionally distinct alleles, corresponding to the most common M/L photopigment variants inferred from a physiological study of cone spectral sensitivity in captive Callicebus. Am. J. Primatol. 73:189–196, 2011. © 2010 Wiley‐Liss, Inc.
Diet and ranging behavior of the endangered Javan gibbon (Hylobates moloch) in a submontane tropical rainforest
Authors: Kim Sanha , Lappan Susan , Choe Jae C.
Published: October 2010

Altitude influences forest structure and food abundance and distribution, which in turn affect primate feeding and ranging patterns. Javan gibbons (Hylobates moloch) are endemic to forests spanning a broad range of altitudes on Java, Indonesia. Most information about Javan gibbon behavior comes from studies in lowland forests, while the vast majority of wild gibbons remaining inhabit hill and lower montane forests. We studied the diets, activity patterns, and ranging behavior of three gibbon groups in hill/lower montane (950–1,100 m asl) forest in the Gunung Halimun‐Salak National Park (GHSNP) from April 2008 to March 2009. The mean home range size was 37 ha and the mean daily path length was 1,180 m. The study groups spent 36% of time feeding, 41% resting, 15% traveling, 6% engaging in social behavior, and 2% in aggressive interactions. Fruit was the most important food (63% of feeding time) followed by leaves (24%), and flowers (12%). Our results suggest that Javan gibbons in higher elevation habitats have substantially larger home ranges than lowland populations, despite broad similarity in their activity budgets and diets. Conservation managers should consider the effects of altitude and habitat quality on gibbon ranging behavior when developing habitat corridors, selecting sites for translocation or reintroduction projects, and designating and managing protected areas. Am. J. Primatol. 73:270–280, 2011. © 2010 Wiley‐Liss, Inc.
Uniaxial strain in graphene and armchair graphene nanoribbons: An ab initio study
Authors: Rosenkranz N. , Mohr M. , Thomsen C.
Published: October 2010

We report first‐principles studies on the electronic and vibrational properties of uniaxially strained graphene and graphene nanoribbons. The band structure of extended graphene shows an interesting behavior under uniaxial strain in directions other than the zigzag or armchair direction. While strained graphene remains semi‐metallic, one‐dimensional graphene nanoribbons allow band‐gap tuning via strain. The shift of the strain‐induced band‐gap in armachair nanoribbons depends on their family. At small strain the band‐gap of all AGNRs depends linearly on the amount of strain. Concerning the vibrational spectra, we compare strain‐induced shift rates of the G modes in two‐dimensional graphene and AGNRs. The shift rates of the G‐ and G+ modes in AGNRs strongly reflect the common classification into three families. For large ribbon widths all shift rates converge to their counterparts in graphene.
Raman scattering on nanomaterials and nanostructures
Authors: Popović Z.V. , Dohčević‐Mitrović Z. , Šćepanović M. , Grujić‐Brojčin M. , Aškrabić S.
Published: October 2010

The conventional Raman scattering spectroscopy is one of the most used and powerful techniques for characterization of nano‐sized materials and structures. By proper analysis of optical mode shift and broadening in nanomaterials based on phonon confinement model, it is possible to deduce about the influence of various effects like particle size and size distribution, strain, change of phonon dispersion, substitutional effects, defect states and nonstoichiometry, electron‐phonon coupling. We have demonstrated potentials of this technique in CeO2 and TiO2 nanocrystalline systems analyzing their optical phonon properties.
The quantum Boltzmann equation in semiconductor physics
Authors: Snoke D.W.
Published: October 2010

The quantum Boltzmann equation, or Fokker‐Planck equation, has been used to successfully explain a number of experiments in semiconductor optics in the past two decades. This paper reviews some of the developments of this work, including models of excitons in bulk materials, electron–hole plasmas, and polariton gases.
MgCl2‐supported catalyst containing mixed internal donors for propylene polymerization
Authors: Gao Futang , Xia Xianzhi , Mao Bingquan
Published: October 2010

A MgCl2‐supported catalyst containing diisobutyl phthalate (DIBP) and 2,4‐pentadiol dibenzoate (PDDB) as internal donors was prepared. Propylene polymerizations were carried out using the catalyst in the absence or presence of an external donor. The resulting polymers were characterized by 13C‐NMR, crystallization analysis fraction (CRYSTAF) and gel permeation chromatography (GPC). The performance of the catalyst was compared with that of other catalysts containing donor‐free, DIBP and PDDB as internal donors respectively. The results demonstrated that the catalyst containing mixed internal donors not only had high activity and stereospecificity but also produced the polymer with relatively broad molecular weight distribution and the highest [mmmm] value. 13C‐NMR analysis results indicated that strongly coordinating donors gave more stereoregular polymers, which was further confirmed by CRYSTAF data. The effects of mixed internal donors on the catalyst properties were discussed systematically. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Architecture of colloidal crystals constructed by silica hybrid nanoparticles
Authors: Ishizu Koji , Tokuno Yoko , Lee Dong Hoon , Uchida Satoshi , Ozawa Masaaki
Published: October 2010

Silica (SiO2)‐crosslinked polystyrene (PS) particles possessing photofunctional N,N‐diethyldithiocarbamate (DC) groups on their surface were prepared by the free‐radical emulsion copolymerization of a mixture of SiO2 (diameter Dn = 192 nm), styrene, divinyl benzene, 4‐vinylbenzyl N,N‐diethyldithiocarbamate (VBDC), and 2‐hydroxyethyl methacrylate with a radical initiator under UV irradiation. In this copolymerization, the inimer VBDC had the formation of a hyperbranched structure by a living radical mechanism. These particles had DC groups on their surface. Subsequently, poly(methyl methacrylate) brushes encapsulated SiO2 particles were synthesized by the grafting from a photoinduced atom transfer radical polymerization (ATRP) approach of methyl methacrylate initiated by SiO2‐crosslinked PS particles as a macroinitiator. We constructed the colloidal crystals using these photofunctional particles. Moreover, the SiO2 particle array of colloidal crystals was locked by radical photopolymerization with vinyl monomer as a matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Influence of the reactive processing of recycled poly(ethylene terephthalate)/poly(ethylene‐co‐glycidyl methacrylate) blends
Authors: Kunimune Noriaki , Yamada Kazushi , Leong Yew Wei , Thumsorn Supaphorn , Hamada Hiroyuki
Published: October 2010

The effect of the amount of reactive additive and screw speed during extrusion on the morphological characteristics and mechanical performance of recycled poly(ethylene terephthalate)(RPET) was investigated. With an increase in the ethylene–glycidyl methacrylate copolymer (E–GMA) additive content, a gradual increase in the Izod impact strength of the RPET/E–GMA blends was initially recorded. Subsequent increases in the E–GMA content to above 13.5 wt % led to a drastic enhancement in the toughness of the blends. Meanwhile, the density of the blends decreased with increasing amount of the additive E–GMA. The toughness and density of the blends were found to be dependent on the screw rotation speed during the extrusion. In addition, ductile and microporous structures were observed on the Izod impact fracture surfaces. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and curing properties of a novel curing agent based on N‐(4‐hydroxyphenyl) maleimide and dicyclopentadiene moieties
Authors: Liu Jia , Zeng Xiao‐Liang , Zhang Xu‐Yong , Xia Xin‐Nian
Published: October 2010

A new type of epoxy resin curing agent, containing pendant phenol functions, was synthesized by the free‐radical copolymerization of N‐(4‐hydroxyphenyl) maleimide with dicyclopentadiene (DCPD) monomer in the presence of a radical initiator. The chemical structure was characterized with Fourier transform infrared spectroscopy and nuclear magnetic resonance. The molecular weight of the new curing agent was determined by gel permeation chromatography. The activity and activation energy of this new curing agent with o‐cresol formaldehyde novolac epoxy (CNE) was investigated with a nonisothermal differential scanning calorimetry technique at different heating rates. The thermal properties of the cured polymers were evaluated with thermogravimetric analysis, and the results exhibit good thermal stability. In addition, this new curing agent with CNE showed low moisture absorption because of the hydrophobic nature of the DCPD structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Cure kinetics of a glass/epoxy prepreg by dynamic differential scanning calorimetry
Authors: Hayaty Mehran , Beheshty Mohammad Hosain , Esfandeh Masoud
Published: October 2010

Dicyandiamide (DICY)‐cured epoxy resins are important materials for structural adhesives and matrix resins for fiber‐reinforced prepregs. Dynamic differential scanning calorimetry (DSC) with heating rates of 2.5, 5, 10, and 15°C/min was used to study the curing behavior of the epoxy prepreg Hexply 1454 system, which consisted of diglycidyl ether of bisphenol A, DICY, and Urone reinforced by glass fibers. The curing kinetic parameters were determined with three different methods and compared. These were the Kissinger, Ozawa, and Borchardt–Daniels kinetic approaches. The lowest activation energy (76.8 kJ/mol) was obtained with the Kissinger method, whereas the highest value (87.9 kJ/mol) was obtained with the Borchardt–Daniels approach. The average pre‐exponential factor varied from 0.0947 × 109 to 2.60 × 109 s−1. The orders of the cure reaction changed little with the heating rate, so the effect of the heating rate on the reaction order was not significant. It was interesting that the overall reaction order obtained from all three methods was nearly constant (≅2.4). There was good agreement between all of the methods with the experimental data. However, the best agreement with the experimental data was seen with the Ozawa kinetic parameters, and the most deviation was seen with the Borchardt kinetic parameters. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Ionic salt permeability through phase‐separated membranes composed of amphoteric polymers
Authors: Ito Eri , Higuchi Masahiro , Yamamoto Katsuhiro , Nagata Kenji , Kinoshita Takatoshi
Published: October 2010

Amphoteric copolymers composed of hydrophilic poly(dimethyl acrylamide) and hydrophobic poly(dimethyl siloxane) formed phase‐separated membranes. The hydrophilic and hydrophobic components formed continuous phase‐separated domains in the membranes. The hydrated poly(dimethyl acrylamide) domains formed membrane‐spanning pathways, which permitted an ionic salt to permeate the membranes. The permeability of the ionic salt through the amphoteric copolymer membranes was studied. On the basis of the results, the mechanism of salt transport could be explained by the free‐volume theory, which was used for the analysis of diffusive transport in the hydrated, homogeneous membranes. The diffusion coefficient of the ionic salt increased exponentially as the volume ratio of the hydrophilic polymer to water [(1 − H)/H, where H is the degree of hydration] decreased in the membrane. It was possible to postulate that the diffusion of the ionic salt through the membranes was dependent on the free‐volume fractions of water and hydrophilic poly(dimethyl acrylamide) domains in the membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized iPP/EPDM blends
Authors: Wang Wei‐Kang , Yang Wei , Bao Rui‐Ying , Xie Bang‐Hu , Yang Ming‐Bo
Published: October 2010

The effect of repetitive processing on the mechanical properties and fracture toughness of dynamically vulcanized isotactic polypropylene/ethylene‐propylene‐diene rubber blends (TPVs) with and without addition of β‐nucleating agent (β‐NA) was studied. The results showed that the repetitive processing did not cause much loss in the mechanical properties of TPVs, especially for TPVs with β‐NA, and TPVs with β‐NA showed better performance stability than TPVs without β‐NA. Essential work of fracture (EWF) approach was used to study the fracture behavior, and the results showed that the value of we (the specific essential work of fracture) of TPVs without β‐NA showed a significant decrease while that of TPVs with β‐NA almost kept constant after repetitive processing. Differential scanning calorimetry and wide‐angle X‐ray diffraction were used to study the variation of crystalline structures, and the results indicated that the repetitive processing showed no significant influence on the crystalline structures of TPVs, and the β‐NA maintained high‐nucleating efficiency after repetitive processing. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the viscosity and processing parameters on the surface resistivity of polypropylene/multiwalled carbon nanotube and ethylene–propylene–diene/multiwalled carbon nanotube nanocomposites
Authors: Min Kyoung‐Tae , Kim Gue‐Hyun
Published: October 2010

In this study, relatively large amounts of polypropylene (PP) and ethylene–propylene–diene (EPDM) were melt‐mixed with multiwalled carbon nanotubes (MWCNTs). Although the melt‐compounding method has many advantages, the uniform dispersion of carbon nanotubes in the polymer matrix is still the most challenging task. Because the electrical conductivity of composites is strongly influenced by the filler's state of dispersion and the extent of filler breakage during processing, the effects of the viscosity and processing conditions, such as the mixing time, rotor speed, and cooling rate, on the surface resistivity were studied. The PP/MWCNT nanocomposites displayed a high dependence of surface resistivity on the cooling rate, and the EPDM/MWCNT nanocomposites displayed a higher surface resistivity at the same content of MWCNTs and less dependence of surface resistivity on the cooling rate compared with PP/MWCNT nanocomposites. The increased surface resistivity of the EPDM/MWCNT nanocomposites was observed when EPDM with higher viscosity was used to prepare the EPDM/MWCNT nanocomposites. By increasing the rotor speed, lower surface resistivity was obtained in the PP/MWCNT nanocomposites. However, by increasing the rotor speed, a higher surface resistivity was obtained in the EPDM/MWCNT nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Control of molecular weight distribution for polypropylene obtained by a commercial Ziegler–Natta catalyst: Effect of a cocatalyst and hydrogen
Authors: Zhang He‐Xin , Lee Young‐Joo , Park Joon‐Ryeo , Lee Dong‐Ho , Yoon Keun‐Byoung
Published: October 2010

The polymerization of propylene was carried out with an MgCl2‐supported TiCl4 catalyst (with diisobutyl phthalate as an internal donor) in the absence and presence of hydrogen (H2) as a chain‐transfer agent. Different structures of alkylaluminum were used as cocatalysts. The effects of the alkyl group size of the cocatalyst, H2 feed, and feed time on the propylene polymerization behaviors were investigated. The catalyst activity significantly decreased with increasing alkyl group size in the cocatalyst. The molecular weight and polydispersity index (PDI) increased with increasing alkyl group size. With the introduction of H2, the catalyst activity increased significantly, whereas the molecular weight and PDI of polypropylene (PP) decreased. Additionally, the effect of the polymerization time in the presence of H2 on the propylene polymerization was studied. The molecular weight distribution curve was bimodal at short polymerization times in the presence of H2, and we could control the molecular weight distribution of PP by changing the polymerization time in the presence of H2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Aerobic oxidative polymerization of 2,6‐dimethylphenol in water with a highly efficient copper(II)– poly(N‐vinylimidazole) complex catalyst
Authors: Zhang Wenli , Wang Huan , Shentu Baoqing , Gu Cheng , Weng Zhixue
Published: October 2010

A Cu(II)–poly(N‐vinylimidazole) (PVI) complex was prepared and used to catalyze the oxidative polymerization of 2,6‐dimethylphenol (DMP) to form poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) in water. The stoichiometric ratio between imidazole groups in PVI and copper ions was found to be 4 when continuous variation analysis was applied. Compared with a conventional Cu(II)–low‐molecular‐weight ligand complex, a high catalytic efficiency was observed in the polymerization of DMP catalyzed by the Cu(II)–PVI complex. The influence of the Cu(II)–PVI complex concentration and imidazole/Cu(II) molar ratio on the oxidative polymerization of DMP was studied. Both the yield and molecular weight of PPO increased significantly with the catalyst concentration and decreased with the imidazole/Cu(II) molar ratio. The molecular weight of PVI also played an important role in the improvement of the catalytic efficiency. The high catalytic efficiency of the Cu(II)–PVI complex may have been due to the concentration effect of the catalyst and substrate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polymerization of epoxidized soybean oil with maleinized polybutadiene
Authors: Öztürk Cem , Küsefoğlu Selim H.
Published: October 2010

Epoxidized soybean oil (ESO) triglycerides were reacted with maleinized polybutadiene (MMPBD) to give plant‐oil‐based thermoset polymers. MMPBD samples were of two different molecular weights [high‐molecular‐weight maleinized polybutadiene (MMPBD‐H), maleate content = 10%, number‐average molecular weight (Mn) = 9000, and low‐molecular‐weight maleinized polybutadiene (MMPBD‐L), maleate content = 15%, Mn = 5000]. To increase the crosslink density of the product, a free‐radical initiator, benzoyl peroxide, was added to this mixture to further crosslink MMPBD through its double bonds. The characterizations of the products were done by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and IR spectroscopy. The ESO–MMPBD polymers were crosslinked rigid infusible polymers. ESO–MMPBD‐H–1 : 1 and ESO–MMPBD‐L–1 : 1 showed glass‐transition temperature values at −23, 78 and −17, 64°C, respectively, whereas the storage moduli of the two polymers at 25°C were 13 and 16 MPa, respectively. The storage moduli of the polymers remained the same or decreased with the addition of a free‐radical initiator. The storage moduli also decreased with increasing ESO concentration above a 1 : 1 epoxy‐to‐anhydride molar ratio. The surface hardness increased dramatically, and the equilibrium swelling ratio decreased with the addition of free‐radical initiator. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
New hybrid system: Poly(ethylene glycol) hydrogel with covalently bonded pegylated nanotubes
Authors: Saez‐Martinez Virginia , Garcia‐Gallastegui Ainara , Vera Carolina , Olalde Beatriz , Madarieta Iratxe , Obieta Isabel , Garagorri Nerea
Published: October 2010

Hydrogels containing carbon nanotubes (CNTs) are expected to be promising conjugates because they might show a synergic combination of properties from both materials. Most of the hybrid materials containing CNTs only entrap them physically, and the covalent attachment has not been properly addressed yet. In this study, single‐walled carbon nanotubes (SWNTs) were successfully incorporated into a poly(ethylene glycol) (PEG) hydrogel by covalent bonds to form a hybrid material. For this purpose, SWNTs were functionalized with poly(ethylene glycol) methacrylate (PEGMA) to obtain water‐soluble pegylated SWNTs (SWNT–PEGMA). These functionalized SWNTs were covalently bonded through their PEG moieties to a PEG hydrogel. The hybrid network was obtained from the crosslinking reaction of poly(ethylene glycol) diacrylate prepolymer and the SWNT–PEGMA by dual photo‐UV and thermal initiations. The mechanical and swelling properties of the new hybrid material were studied. In addition, the material and lixiviates were analyzed to elucidate any kind of SWNT release and to evaluate a possible in vitro cytotoxic effect. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Suitability of different salmonid strains as hosts for the endangered freshwater pearl mussel (Margaritifera margaritifera L.)
Authors: Taeubert Jens‐Eike , Denic Marco , Gum Bernhard , Lange Michael , Geist Juergen
Published: October 2010

The complex life cycle of endangered European freshwater pearl mussel Margaritifera margaritifera L. involves an obligatory parasitic phase on a host fish. Knowledge on the host–parasite interaction and on the suitability of different host fish species and strains is required both for the management of wild fish and mussel populations as well as for improving the efficiency of captive breeding methods.

In this study, the suitability of different salmonid strains for hosting glochidia was tested, including Danube salmon (Hucho hucho L.) and three brown trout (Salmo trutta L.) strains from inside and outside the freshwater pearl mussel distribution range. All brown trout strains as well as Danube salmon were successfully infected with freshwater pearl mussel glochidia and encystment of mussel larvae was detected.

One brown trout strain originating from the natural pearl mussel distribution range was identified as the most suitable host, revealing the highest fish‐weight‐normalized infection rates and highest glochidial growth rates, whereas endemic Danube salmon was least suitable. Under natural conditions, the role of Danube salmon may be attributed to the long‐distance dispersal of glochidia in the Danube system, whereas sedentary brown trout appear to be the most important hosts at a local scale.

Successful infection of suitable hosts and the maintenance of these host–parasite systems in calcareous water were demonstrated in this study. These results indicate that neither the infection process nor the encystment phase of freshwater pearl mussels is dependent on low lime concentrations.

The results of this study suggest that careful selection and management of appropriate host fish strains is mandatory for sustainable conservation management of freshwater pearl mussel populations. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and Pharmacological Evaluation of Some 4‐Oxo‐quinoline‐2‐carboxylic Acid Derivatives as Anti‐inflammatory and Analgesic Agents
Authors: Mazzoni Orazio , Esposito Giovanni , Diurno Maria Vittoria , Brancaccio Diego , Carotenuto Alfonso , Grieco Paolo , Novellino Ettore , Filippelli Walter
Published: October 2010

The synthesis and the pharmacological activity of a series of 1‐aroyl derivatives of kynurenic acid methyl ester (4‐oxo‐quinolin‐2‐carboxy methyl (KYNA) esters), structurally related to NSAID indomethacin are described. The derivatives were screenedin vivofor anti‐inflammatory and analgesic activities. Most of the compounds exhibited good anti‐inflammatory and analgesic activities. An automatic docking of the synthesized compounds was performed using X‐ray structures of COX‐1 and COX‐2. Docking results are in good accordance with the experimental biological data.
Chimeric avidin shows stability against harsh chemical conditions—biochemical analysis and 3D structure
Authors: Määttä Juha A.E. , Eisenberg‐Domovich Yael , Nordlund Henri R. , Hayouka Ruchama , Kulomaa Markku S. , Livnah Oded , Hytönen Vesa P.
Published: October 2010

Avidin and its bacterial analog streptavidin have been widely used in applications in life sciences. Recently, we described a highly thermostable engineered avidin, called chimeric avidin, which is a hybrid of avidin and avidin‐related protein 4. Here, we report a protocol for pilot‐scale production in E. coli and the X‐ray structure of chimeric avidin. The ligand‐binding properties of chimeric avidin were explored with isothermal titration calorimetry. We found chimeric avidin to be more stable against various harsh organic solvents at elevated temperatures compared to avidin and streptavidin. The properties of chimeric avidin make it a potential tool for new applications in biotechnology. Biotechnol. Bioeng. 2011; 108:481–490. © 2010 Wiley Periodicals, Inc.
Effects of water miscible organic solvents on the activity and conformation of the baeyer–villiger monooxygenases from Thermobifida fusca and Acinetobacter calcoaceticus: A comparative study
Authors: Secundo Francesco , Fialà Stefano , Fraaije Marco W. , de Gonzalo Gonzalo , Meli Massimiliano , Zambianchi Francesca , Ottolina Gianluca
Published: October 2010

A broader exploitation of enzymes in organic synthesis can be achieved by increasing their tolerance toward organic solvents. In this study, the stability and activity of Baeyer–Villiger monooxygenases from Thermobifida fusca (PAMO) and Acinetobacter sp. (CHMO) in the presence of water miscible organic solvents were compared. PAMO was more stable than CHMO. The concentration of solvent (v/v) at which it halved its activity (C50) was 4‐ to 16‐fold higher than that observed for CHMO. For PAMO, the C50 varied from 16% to 55% of solvent and followed the destabilizing order methanol < ethanol < 1,4‐dioxane < acetonitrile < trifluoroethanol. In the case of CHMO, the maximal C50 was 7% with methanol and even lower with the other solvents. Therefore, methanol was the most tolerated solvent. In the case of PAMO, methanol induced a significant increase of enzyme activity (up to fivefold), which was optimal at 20% (v/v) solvent. Only minor spectral variations were observed with PAMO in 20% methanol, suggesting that the increase of activity observed in this condition is not due to marked conformational changes. Fluorescence and circular dichroism analyses showed that the lower stability of CHMO toward organic solvent correlates with a more pronounced destructive effect on its secondary and tertiary structure. A possible rationale for the higher stability of PAMO could be inferred from inspection of the PAMO and CHMO (two enzymes of similar size) structure, which revealed a higher (up to twofold) number of ionic bridges in PAMO with respect to CHMO. Biotechnol. Bioeng. 2011; 108:491–499. © 2010 Wiley Periodicals, Inc.
Role of iron and sodium citrate in animal protein‐free CHO cell culture medium on cell growth and monoclonal antibody production
Authors: Bai Yunling , Wu Changjian , Zhao Jia , Liu Yan‐Hui , Ding Wei , Ling Wai Lam W.
Published: October 2010

Chemically defined iron compounds were investigated for the development of animal protein‐free cell culture media to support growth of CHO cells and production of monoclonal antibodies (mAb). Using a multivessel approach of 96‐well plates, shake flasks, and bioreactors, we identified iron and its chemical partner citrate as critical components for maintenance of continuous cell growth and mAb production. The optimized iron concentration range was determined to be 0.1–0.5 mM and that for citrate 0.125–1 mM. This complete formulation is able to maintain cell growth to similar levels as those supplemented with iron compounds alone; however, mAb productivity was enhanced by 30–40% when citrate was present. The addition of sodium citrate (SC) did not affect product quality as determined by size exclusion chromatography, ion exchange chromatography, reversed phase and normal phase‐HPLC. No significant changes in glucose and lactate profiles, amino acid utilization, or mAb heavy and light chain expression ratios were observed. Cellular ATP level was ∼30% higher when SC was included suggesting that SC may have a role in enhancing cellular energy content. When cell lysates were analyzed by LC‐MS to assess the overall cellular protein profile, we identified that in the SC‐containing sample, proteins involved in ribosome formation and protein folding were upregulated, and those functions in protein degradation were downregulated. Taken together, this data demonstrated that iron and citrate combination significantly enhanced mAb production without altering product quality and suggested these compounds had a role in upregulating the protein synthetic machinery to promote protein production. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Two‐phase bioreactor system for cell‐laden hydrogel assembly
Authors: Gulfam Muhammad , Lee Jong Min , Chung Bong Geun
Published: October 2010

Bottom‐up approach is a potentially useful tool for hydrogel assembly of cell‐laden individual building blocks. In this article, we assembled individual building blocks of photocrosslinkable microgels in a rapid and controlled manner. Individual building blocks of poly(ethylene glycol) (PEG) microgels with square and hexagonal shapes were fabricated by using a photolithography technique. Individual building blocks of PEG microgels were assembled on a hydrophobic mineral oil phase in a bioreactor with a magnetic stirrer. The hydrophobic mineral oil minimized the surface free energy to assemble hydrophilic PEG microgels on a two‐phase oil‐aqueous solution interface. We used the hydrophobic effect as a driving force for the hydrogel assembly. Various types of the hydrogel assembly were generated by controlling the stirring rate. As stirring speed increased, the percentage of linear, branched, and closely packed hydrogel assembly was increased. However, the percentage of random assembly was reduced by increasing stirring rate. The stirring time also played an important role in controlling the types of hydrogel assembly. The percentage of linear, branched, and closely packed hydrogel assembly was improved by increasing stirring time. Therefore, we performed directed cell‐laden hydrogel assembly using a two‐phase bioreactor system and optimized the stirring rate and time to regulate the desired types of hydrogel assembly. Furthermore, we analyzed cell viability of hydrogel linear assembly with square shapes, showing highly viable even after secondary photocrosslinking reaction. This bioreactor system‐based hydrogel assembly could be a potentially powerful approach for creating tissue microarchitectures in a three‐dimensional manner. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Immobilization of organophosphate hydrolase on an amyloid fibril nanoscaffold: Towards bioremediation and chemical detoxification
Authors: Raynes Jared K. , Pearce F.Grant , Meade Susie J. , Gerrard Juliet A.
Published: October 2010

Organophosphate hydrolase has potential as a bioremediation and chemical detoxification enzyme, but the problems of reusability and stability need to be addressed to use this enzyme on an industrial scale. Immobilizing the enzyme to a nanoscaffold may help to solve these problems. Amyloid fibrils generated from insulin and crystallin provided a novel nanoscaffold for the immobilization of organophosphate hydrolase, using glutaraldehyde as the crosslinking reagent. Electrophoretic, centrifugation, and temperature stability experiments, together with transmission electron microscopy were undertaken to verify that crosslinking had successfully occurred. The resulting fibrils remained active towards the substrate paraoxon and when immobilized to the insulin amyloid fibrils, the enzyme exhibited a significant (∼300%) increase in the relative temperature stability at 40, 45, and 50°C (as measured by comparing the initial enzyme activity to the activity remaining after heating), compared to free enzyme. This confirms that amyloid fibrils could provide a new type of nanoscaffold for enzyme immobilization. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Screening for enzyme activity in turbid suspensions with scattered light
Authors: Huber Robert , Wulfhorst Helene , Maksym Lukas , Stehr Regina , Pöhnlein Martin , Jäger Gernot , Spieß Antje C. , Büchs Jochen
Published: October 2010

New screening techniques for improved enzyme variants in turbid media are urgently required in many industries such as the detergent and food industry. Here, a new method is presented to measure enzyme activity in different types of substrate suspensions. This method allows a semiquantitative determination of protease activity using native protein substrates. Unlike conventional techniques for measurement of enzyme activity, the BioLector technology enables online monitoring of scattered light intensity and fluorescence signals during the continuous shaking of samples in microtiter plates. The BioLector technique is hereby used to monitor the hydrolysis of an insoluble protein substrate by measuring the decrease of scattered light. The kinetic parameters for the enzyme reaction (Vmax,app and Km,app) are determined from the scattered light curves. Moreover, the influence of pH on the protease activity is investigated. The optimal pH value for protease activity was determined to be between pH 8 to 11 and the activities of five subtilisin serine proteases with variations in the amino acid sequence were compared. The presented method enables proteases from genetically modified strains to be easily characterized and compared. Moreover, this method can be applied to other enzyme systems that catalyze various reactions such as cellulose decomposition. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
A review of advanced small‐scale parallel bioreactor technology for accelerated process development: Current state and future need
Authors: Bareither Rachel , Pollard David
Published: October 2010

The pharmaceutical and biotech industries face continued pressure to reduce development costs and accelerate process development. This challenge occurs alongside the need for increased upstream experimentation to support quality by design initiatives and the pursuit of predictive models from systems biology. A small scale system enabling multiple reactions in parallel (n ≥ 20), with automated sampling and integrated to purification, would provide significant improvement (four to fivefold) to development timelines. State of the art attempts to pursue high throughput process development include shake flasks, microfluidic reactors, microtiter plates and small‐scale stirred reactors. The limitations of these systems are compared to desired criteria to mimic large scale commercial processes. The comparison shows that significant technological improvement is still required to provide automated solutions that can speed upstream process development. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Interactive dimensional calibration via Internet
Authors: Gomez E. , Caja J. , Maresca P. , Barajas C. , Berzal M.
Published: October 2010

The purpose of this article is to show a software application made for online calibration via Internet from simple measuring instruments from the dimensional area (exterior micrometer and calliper). It also shows the educational results obtained in the teaching experiences where it has been used. The environment created makes it possible to replace real practices with virtual simulations where the student must make the proper metrological decisions and make the necessary calculations to determine the instruments' expanded uncertainty. This software has shown to be a very useful and efficient tool in training the distance learning students in the course titled: “Calibration Plan for Ensuring Quality in Industrial Laboratories,” offered by Technical University of Madrid. Furthermore, some very notable academic results have been achieved among students from two pilot groups for the Mechanical Engineering degree program. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 21: 387–399, 2013