bluuebunny/crossref_metadata_2025 huggingface dataset:
Sustainable Development and Change Management
Authors: Sherman Robert
Published: April 2008

The evolution of sustainability from an initially perceived environmental/philanthropic initiative to a fully integrated business concept is taking place with increasing frequency and speed within corporations. The definition of sustainability is highly subjective, which can create barriers to understanding within an organization. In addition, the execution of sustainability strategies is dependent on the needs and expectations of the organization's external stakeholders. These stakeholders vary depending on a variety of factors including location (i.e., developed or developing nations), established or emerging markets, customer acceptability, availability of local workforce, suitability of local economies, and the structure of local governments.

This paper discusses the progression of the sustainability concept within the company and the management of the change in attitude on the issue throughout the organization. The understanding of sustainability as a core value and strategic consideration and the struggle to consolidate differing views regarding the implications of sustainability are also discussed.
Raising Awareness Among and Training Contractors
Authors: Calvo V. , Violini C.
Published: April 2008

In accordance with the commitment assumed by Repsol YPF to carry out its activities considering safety, people's health and protection of the environment as essential values, and within the framework of Management Excellence Through Continuous Improvement, the Argentina Oeste Business Unit of Exploration and Production has implemented the "Raising Awareness Among and Training Contractors" project.

This project is focused on three concepts: Responsibility of the Chain of Command, Operative Discipline, and Security Alert; and, in the attempt to comply with the "doing-things-right" standard, it is based on the following three pillars and their respective topics: Plan of Attack: Work observations, Work permits, Raising awareness about Safety and Leadership, Contingency Plan.Induction Plan: Industrial generalities, Preservation of the environment, Elements of personal protection, Vehicular traffic, Emergency calls.Basic Training: Environmental policy, Safety and Quality, Applicable regulations, Environmental aspects, Labor risks, Specific procedures, Competences certification.

The general scope of this project involves people from the 300 contractor and subcontractor companies that operate in the fields of hydrocarbon extraction and exploitation, operations supervisors and contract inspectors from YPF SA.

It is important to highlight that verifying the effectiveness of the implementation results by using different techniques has been considered as part of the objective of this project.

The project management (planning, control and follow-up) is being done according to the guidelines and good practices defined by the Project Management Office (PMO) of the MASC-UNAO Management.

The results obtained in relation to the evolution of the work observations carried out together with the accidents frequency rates and the amount of trained people will be shown on this paper. The conclusions will stem from the analysis of the results.
Drilling Waste Management Plans for Exploration and Production Operations in Iran
Authors: Mohammadi M. Kalhor , Tahmasbi K.
Published: April 2008

More than 200 wells are drilled in Iran for exploration and development operations every year. These drilling operations would annually generate millions of barrels of wastes that has become a main problem for the major operators and their future liabilities. Also, the total well construction cost increases by increasing environmental restriction every year.

For many years, traditional drilling fluids and solids control equipment have been used and there has not been any drilling waste management strategy to minimize the wastes. In addition, traditional disposal options are used at the site without any treatments or practices before discharge of the wastes. Today, operators are looking for implementing cost effective waste management practices and treatments to meet the environmental requirements in Iran.

This paper will introduce a drilling waste management plan with operational practices for waste minimization, re-cycling and disposal by considering the environmental legislation and the economy of the drilling operations. Also, operational requirements will be discussed for treating drilling fluids wastes and contaminated cuttings with the instruction for measuring generated waste.

In conclusion, implementing new technologies for drilling waste management requires long term goals for operators with environmental and economical investigations to keep them in compliance with current regulations. It should be considered that monitoring and reviewing the waste management practices can improve the performance of the designed plan for a country such as Iran with consecutive increase in drilling operations.
Health Circles—A Tool for Work Place Health Promotion in the Oil Industry
Authors: Schunder-Tatzber Susanne , Unterberger Werner
Published: April 2008

Traditional efforts concerning occupational safety and health with the focus on individuals and the physical working environment are often not sufficient to meet the spectrum health problems in modern working life. The target of health promotion programs in the workplace has often been the individual rather than the underlying working conditions that affect health and wellness. Traditional workplace practices need to be complemented by a wider public health perspective that integrates the level of the individual with the group and the company or organisation. The idea of healthy organisations can only be reached by a stronger involvement of employees and a closer collaboration with managers. One way to reach this aim is Workplace Health Promotion (WHP) and a specific tool is Health Circles. These Circles should develop proposed solutions for job design in a manner, which promotes health, and to increase the individual's responsibilities and competencies for his/her own health – so it is a bottom – up approach tool, which requires the active involvement of the workforce. Health Circle focuses on short-and mid-term improvements of working conditions and aspects of job design and will not alter the organisational structures of the company.

Health Circles should look at the working environment in their particular work units – like workstation ergonomics or organisational dynamics, which have impact on the health. According to the fact, that this tool demonstrated its effectiveness in some works sites of OMV since 1996, it was decided to implement Health Circles group-wide in OMV.

An OMV Health Circle has at least one moderator, who guides the group and reports the findings to the OMV Health Circle Steering Committee. These moderators should have experience in their specific work, should be accepted by their peers and should have to follow a specific Health Circle moderator training, where the participants learn about the aims of WHP, Health Circle and methods of moderating and presenting.

According to international experience optimal groups have between 6 -12 members – and every single employee could become a member and they meet normally 1-2 times for 1-2 h a month/quarter during paid working time.
Europ Assistance's New Approach of Clinic and Patient Management Tools: An Integrated Solution
Authors: Belliard P. A.
Published: April 2008

As a medical provider we were faced with a common dilemma: how to efficiently manage the medical support to Oil & Gas companies, who have very specific needs and obligations, with tools that were developed for entirely different uses. After investigating the solutions available on the market, it became clear that none would meet all the above-mentioned requirements. Those "off the shelf" solutions would need to either be completely revamped or to be used in conjunction with other incomplete solutions in order to approach the level of excellence that we were looking for, but never really attain it. We identified two main groups of existing solutions: the first group was made up of very complex systems designed for the management of hospitals, while the second one was comprised of much lighter solutions aimed at small medical offices. Neither one met the requirements of our very specific activity. Therefore, it was decided to develop a proprietary tools meeting and exceeding our activity's requirements.
Sustainable CSR Activities in Uganda
Authors: Brunton G. , Early M.
Published: April 2008

As an independent oil and gas exploration and production company, Tullow approaches its CSR commitments in a unique way to ensure positive links with the local communities in which it works. The core criteria for Tullow support focuses on assisting children, improving education and providing basic health requirements. An initial dialogue is held with key locals to establish a clear priority of actions then the Team look at ways of achieving these improvements in a sustainable way.

Two such examples from the Tullow Uganda operations which highlight this are described in the paper. The first outlines the lifejacket project where Tullow worked with a local company employing people from the villages to make internationally certified lifejackets. The lifejackets were designed for use by the fishermen on the lake and the project was accompanied by an incentive plan to ensure the lifejackets are worn.

The second example is the Bee Keeping Co-operative where co-operatives were set up in 10 villages to build and manage 200 bee hives with expansion plans to 2000. Sunflowers and fruit trees were planted to provide additional sources of nectar for the bees and to maximise production. Although providing ongoing support and development options, this project is fully sustainable and would function in the area without Tullow involvement.

The paper concludes that Tullow has demonstrated significant and sustainable benefit to the communities in Uganda where it operates. The results of the lifejacket project has shown lives are being saved among the fishing community and the sustainable commercial output from the bee keeping industry has brought prosperity to the village co-operatives and improvements to the quality of life in these areas. The Tullow CSR activities show involvement and alignment with the local communities which are sustainable and successful.
Screening for Human Factors in Process Safety and Technical Integrity
Authors: McLeod Ron
Published: April 2008

Shell Group requires all new facilities projects to apply the principles of Human Factors Engineering (HFE) from early project stages. Shell's HFE process is based around a screening, conducted early in front end engineering, to identify areas of risk or opportunity. The purpose is to identify where a structured programme of Human Factors Engineering can add value either in reducing risk or improving operational performance. This paper summarises the importance of Human Factors Engineering to process safety and technical integrity and provides an overview of the three screening tools used by Shell. It emphasizes the critical importance of Challenge to HFE.
Hydrocarborn Seepage in Former Drilling Mud Pits
Authors: Vicente Elena Luisa
Published: April 2008

For a long time, as an industry accepted practice, the oil companies digged ground drilling pits in well locations. The pits were open and mainly intended to operate as a containment reservoir for drilling and completion fluids. Nevertheless, their useful life did not end in said operation. The pits remained open besides the well to receive solid and liquid waste during their entire useful life.

These problems generated a reaction from the community and from the application authority that, through Resolution 341/93, enforced compliance of schedules for plugging pits according to the criteria of potential risk.

Terms set forth by the application authorities were short, based on the number of open pits, the lack of methodology to be applied and the scarcity of contractors.
Variable Pore Connectivity Factor Model for Gas Diffusivity in Unsaturated, Aggregated Soil
Authors: Resurreccion Augustus C. , Moldrup Per , Kawamoto Ken , Yoshikawa Seiko , Rolston Dennis E. , Komatsu Toshiko
Published: April 2008

The soil gas diffusion coefficient (Dp) and its variations with soil air content (ε) and soil water matric potential (ψ) control vadose zone transport and emissions of volatile organic chemicals and greenhouse gases. This study revisits the 1904 Buckingham power‐law model where Dp is proportional to εX, with X characterizing the tortuosity and connectivity of air‐filled pore space. One hundred years later, most models linking Dp(ε) to soil water retention and pore size distribution still assume that the pore connectivity factor, X, is a constant for a given soil. We show that X varies strongly with both ε and matric potential [given as pF = log(−ψ, cm H2O)] for individual soils ranging from undisturbed sand to aggregated volcanic ash soils (Andisols). For Andisols with bimodal pore size distribution, the X–pF function appears symmetrical. The minimum X value is typically around 2 and was observed close to ψ of −1000 cm H2O (pF 3) when interaggregate voids are drained. To link Dp with bimodal pore size distribution, we coupled a two‐region van Genuchten soil water retention model with the Buckingham Dp(ε) model, assuming X to vary symmetrically around a given pF. The coupled model well described Dp as a function of both ε and ψ for both repacked and undisturbed Andisols and for other soil types. By merely using average values of the three constants in the proposed symmetrical X–pF expression, predictions of Dp were better than with traditional models.
Bacteria Transport and Deposition under Unsaturated Flow Conditions: The Role of Water Content and Bacteria Surface Hydrophobicity
Authors: Gargiulo G. , Bradford S. A. , Simunek J. , Ustohal P. , Vereecken H. , Klumpp E.
Published: April 2008

Column experiments were conducted to investigate the transport and deposition behavior of representative hydrophobic and hydrophilic bacteria strains in sand at different water saturations. These strains are similar in surface charge, shape, and size, and differ primarily in their surface hydrophobicity and tendency to form aggregates. The amount of bacteria that were retained in the sand increased with decreasing water saturation, especially for the more hydrophobic strain that formed larger cell aggregates. Most of the cells were retained close to the column inlet, and the rate of deposition rapidly decreased with depth. The experimental data were analyzed using a mathematical model that accounted for deposition on two kinetic sites. Consideration of depth‐dependent deposition in the model formulation significantly improved the description of the data, and the amount of cell retention was typically dominated by this site. The depth‐dependent deposition coefficient tended to increase with decreasing water content, especially for the hydrophobic bacteria. Straining is believed to account for these observations because it increases in magnitude with increasing cell and aggregate size and when a greater fraction of the water flows through a larger number of small pore spaces with decreasing water content. Cell retention on the other kinetic deposition site was well described using a conventional model for attachment and detachment. Consistent with interaction energy calculations for bacteria attachment, however, low amounts of cell retention occurred on this site. Attempts to separately determine the amounts of attachment to solid–water and air–water interfaces were confounded by the influence of straining.
Hematuria and transitional cell papilloma of the renal pelvis treated via unilateral nephrectomy in an alpaca
Authors: Gerspach Christian , Hull Bruce L. , Rings D. Michael , Chew Dennis J. , Beamer Gillian L. , Hubbell John A. E. , Lakritz Jeffrey
Published: April 2008

Case Description—An 11-year-old 72-kg (158-lb) sexually intact female alpaca was examined for diagnosis and treatment of hematuria of 4 months' duration.

Clinical Findings—Pigmenturia was detected by the owner when the alpaca was 8 months pregnant. Radiographic, ultrasonographic, vaginal speculum, and cystoscopic evaluation of the urinary tract revealed normal vaginal and urethral epithelia and increased bladder vessel tortuosity, with pulses of hemorrhage from the left ureter. Regenerative anemia and mild leukopenia were detected and serum urea nitrogen and creatinine concentrations were within reference ranges.

Treatment and Outcome—Chronic hematuria resolved after unilateral nephrectomy of the left kidney, and no dysfunction was detected in the remaining kidney. Histologic evaluation of the kidney revealed a transitional cell tumor in the renal pelvis.

Clinical Relevance—Although anemia is common in South American camelids, hematuria is an uncommon sign of this condition. Chronic urinary tract infection, toxin ingestion, and neoplasia causing hematuria or hemoglobinuria should be considered in South American camelids with pigmenturia. Thorough and systematic evaluation of the urinary tract should be performed to locate the site of hemorrhage to treat hematuria appropriately.
Compositional characterisation and thermodynamic modelling of nitride precipitates in a 12% Cr steel
Authors: Albu Mihaela , Martín Francisca Méndez , Kothleitner Gerald , Sonderegger Bernhard
Published: April 2008

In 9–12% Cr steels, nitrides (MX, M2X) and modified Z-phase ((Cr, V, Nb, Fe)N)) are of special interest because of their different contribution to the creep strength of the material. The changes in the chemical composition of complex nitrides and their crystallography were investigated using transmission electron microscopy. A method based on multiple linear least squares fit procedures was applied to extract the complete element content of the nitrides from the electron energy loss spectra. These results, augmented by X-ray spectroscopic data, were compared with the outcomes of the thermodynamic model implemented in the software package MatCalc. The elemental concentrations of precipitates under study i. e. the M2X, MX and modified Z-phase are in good agreement with simulations.
A simple classification of soil types as habitats of biological soil crusts on the Colorado Plateau, USA
Authors: Bowker Matthew A. , Belnap Jayne
Published: April 2008

Question:

Can a simple soil classification method, accessible to non‐experts, be used to infer properties of the biological soil crust (BSC) communities such as species richness, evenness, and structure?

Location:

Grand Staircase‐Escalante National Monument, an arid region of the Colorado Plateau, USA.

Methods:

Biological soil crusts are highly functional soil surface communities of mosses, lichens and cyanobacteria that are vulnerable to soil surface disturbances such as grazing. We sampled BSC communities at 114 relatively undisturbed sites. We developed an eight‐tier BSC habitat classification based upon soil properties including texture, carbonate and gypsum content, and presence of shrinking‐swelling clays. We used simple structural equation models to determine how well this classification system predicted the evenness, richness, and community structure of BSC relative to elevation and annual precipitation.

Results:

We found that our habitat classification system explained at least 3.5 × more variance in BSC richness (R2= 0.57), evenness (R2= 0.59), and community structure (R2= 0.34) than annual precipitation and elevation combined. Gypsiferous soils, non‐calcareous sandy soils, and limestone‐derived soils were all very high in both species richness and evenness. Additionally, we found that gypsiferous soils were the most biologically unique group, harboring eight strong to excellent indicator species.

Conclusions:

Community properties of BSCs are overwhelmingly influenced by edaphic factors. These factors can be summarized efficiently by land managers and laypeople using a simple soil habitat classification, which will facilitate incorporation of BSCs into assessment and monitoring protocols and help prioritize conservation or restoration efforts.
Reintegrative Shaming Theory, moral emotions and bullying
Authors: Ttofi Maria M. , Farrington David P.
Published: April 2008

This article investigates the usefulness of Reintegrative Shaming Theory (RST) in explaining the bullying of siblings in families and peers in schools. Questionnaires were completed by 182 children aged 11–12 years in ten primary schools in Nicosia, Cyprus, about sibling and peer bullying. A vignette‐based methodology was used to investigate children's expectations of the type of shaming their parents would offer in response to their possible wrong doing. Children were also asked questions about the emotions they would have felt (i.e. shame, remorse, guilt or anger) if they were in the position of the child in the vignette. The level of bonding toward each parent was also examined. In agreement with the theory, a path analysis showed that mother bonding influenced children's expectations of the type of shaming offered by parents. Disintegrative shaming (i.e. shaming offered in a stigmatizing or rejecting way) had a direct effect on the way children managed their shame. Shame management directly influenced sibling and peer bullying. Father bonding had no direct or indirect effects in the model. Against the theory, reintegrative shaming (i.e. shaming offered in the context of approving the wrongdoer while rejecting the wrongdoing) did not have a direct effect on shame management. Beyond the postulates of RST, mother bonding—a plausible indicator of family functioning—had a direct effect on sibling and peer bullying. Mother bonding had a stronger effect for boys than for girls. It is concluded that RST is useful in explaining the link between family factors and bullying, and that RST has cross‐cultural applicability. Aggr. Behav. 34:352–368, 2008. © 2008 Wiley‐Liss, Inc.
Polymorph Switching of Calcium Carbonate Crystals by Polymer‐Controlled Crystallization
Authors: Xu An‐Wu , Dong Wen‐Fei , Antonietti Markus , Cölfen Helmut
Published: April 2008

Polymer‐controlled crystallization of calcium carbonate crystals in solution by a gas diffusion method has been carried out in the presence of poly(sodium 4‐styrene sulfonate‐co‐N‐isopropylacrylamide) (PSS‐co‐PNIPAAM), and for the first time all three anhydrous polymorphs, calcite, vaterite, and aragonite could be selectively produced with a single additive. The selective polymorph synthesis can be nicely adjusted simply by concentration variations of polymer and calcium ions in the present reaction system. The simplicity of the system reveals the influence of Ca2+ and polymer concentration on the nucleation and crystal growth of CaCO3 via the balance between thermodynamic and kinetic reaction control. A single mechanistic framework employing particle mediated as well as ion mediated crystallization for polymorph control is proposed.
Synthesis of Sulfoximine‐Derived P,N Ligands and their Applications in Asymmetric Quinoline Hydrogenations
Authors: Lu Sheng‐Mei , Bolm Carsten
Published: April 2008

A series of naphthalene‐bridged P,N‐type sulfoximine ligands and their iridium complexes have been synthesized. They were applied in the enantioselective hydrogenation of quinoline derivatives, and enantioselectivities up to 92% ee have been achieved in the hydrogenation of 2‐methylquinoline.
Chemoenzymatic Syntheses of Tumor‐Associated Carbohydrate Antigen Globo‐H and Stage‐Specific Embryonic Antigen 4
Authors: Wang Zhen , Gilbert Michel , Eguchi Hironobu , Yu Hai , Cheng Jiansong , Muthana Saddam , Zhou Luyuan , Wang Peng George , Chen Xi , Huang Xuefei
Published: April 2008

Gangliosides have attracted much attention due to their important biological properties. Herein we report the first chemoenzymatic syntheses of two globo series of ganglioside oligosaccharides, Globo‐H1and stage‐specific embryonic antigen‐4 (SSEA‐4)2. The common precursor SSEA‐3 pentasaccharide for these two compounds was assembled rapidly using the pre‐activation‐based one‐pot glycosylation method. The stereoselectivity in forming the 1,2‐cislinkage in SSEA‐3 was attributed to a steric buttressing effect of the donor rather than electronic properties of the glycosyl donors. SSEA‐3 was then successfully fucosylated by the fucosyltransferase WbsJ and sialylated by sialyltransferases CST‐I and PmST1 producing Globo‐H and SSEA‐4, respectively.
Severe Marfan syndrome due to FBN1 exon deletions
Authors: Blyth Moira , Foulds Nicola , Turner Claire , Bunyan David
Published: April 2008

Marfan syndrome is an autosomal dominant condition, with manifestations mainly in the skeletal, ocular, and cardiovascular systems. The disorder is caused by mutations in fibrillin‐1 gene (FBN1). The majority of these are family‐specific point mutations, with a small number being predicted to cause exon‐skipping. To date, there have only been five reports of in‐frame exon deletions in FBN1, with the largest of these spanning three exons. Mosaicism is rarely recorded and has only been reported in the unaffected, or mildly affected, parents of probands. Here, we report on the clinical histories of two children with exon deletions in FBN1. Both have severe Marfan syndrome with significant signs in infancy. One patient has a deletion of exon 33, which has not previously been reported. The other has the largest reported deletion, which spans 37 exons, and also represents the first reported case of mosaicism in a patient with Marfan syndrome. © 2008 Wiley‐Liss, Inc.
The clinical spectrum of homozygous HOXA1 mutations
Authors: Bosley Thomas M. , Alorainy Ibrahim A. , Salih Mustafa A. , Aldhalaan Hesham M. , Abu‐Amero Khaled K. , Oystreck Darren T. , Tischfield Max A. , Engle Elizabeth C. , Erickson Robert P.
Published: April 2008

We describe nine previously unreported individuals from six families who have homozygous mutations of HOXA1 and either the Bosley–Salih–Alorainy syndrome (BSAS) or the Athabascan brainstem dysgenesis syndrome (ABDS). Congenital heart disease was present in four BSAS patients, two of whom had neither deafness nor horizontal gaze restriction, thus raising the possibility that cardiovascular malformations might be a clinically isolated, or relatively isolated, manifestation of homozygous HOXA1 mutations. Two ABDS probands had relatively mild mental retardation. These individuals blur the clinical distinctions between the BSAS and ABDS HOXA1 variants and broaden the phenotype and genotype of the homozygous HOXA1 mutation clinical spectrum. © 2008 Wiley‐Liss, Inc.
Genetics of post‐traumatic stress disorder: Informing clinical conceptualizations and promoting future research
Authors: Nugent Nicole R. , Amstadter Ananda B. , Koenen Karestan C.
Published: April 2008

The purpose of this article is to provide an overview of genetic research involving post‐traumatic stress disorder (PTSD). First, we summarize evidence for genetic influences on PTSD from family investigations. Second, we discuss the distinct contributions to our understanding of the genetics of PTSD permitted by twin studies. Finally, we summarize findings from molecular genetic studies, which have the potential to inform our understanding of underlying biological mechanisms for the development of PTSD. © 2008 Wiley‐Liss, Inc.
Cerebral impairment in chronic solvent‐induced encephalopathy
Authors: Visser Ieke , Lavini Cristina , Booij Jan , Reneman Liesbeth , Majoie Charles , de Boer Angela G. E. M. , Wekking Elizabeth M. , de Joode Elisabeth A. , van der Laan Gert , van Dijk Frank J. H. , Schene Aart H. , Den Heeten Gerard J.
Published: April 2008

Objective

Worldwide, many workers experience occupational exposure to organic solvents, which may induce chronic solvent‐induced encephalopathy (CSE). Disturbances within the frontostriatothalamic (FST) circuitry might explain the symptomatology of CSE. We tested the hypothesis of FST circuitry abnormalities in CSE, as well as associations with performance of psychomotor speed, attention, and solvent exposure. To detect preclinical, solvent‐related effects, we also studied the FST circuitry in solvent‐exposed, but asymptomatic workers.

Methods

Ten CSE patients, 10 asymptomatic but solvent‐exposed house painters (EC), and 11 nonexposed asymptomatic carpenters were included. Dopamine D2 receptor (D2R) binding, central nervous system tissue metabolites, and fractional anisotropy were measured within the FST circuitry, using single‐photon emission computed tomography, magnetic resonance spectroscopy, and diffusion tensor imaging. Performance of psychomotor speed and attention, and severity of solvent exposure were assessed.

Results

Striatal D2R binding was reduced in CSE. In the solvent‐exposed asymptomatic patients, striatal D2R binding and levels of N‐acetylaspartate + N‐acetylaspartyl‐glutamate in frontal gray matter were reduced. In both exposed groups, a trend was seen for reduced choline in frontal gray matter. In CSE, the fractional anisotropy in the thalamus, caudate nucleus, and striatal D2R binding significantly predicted reduced performance of attention and psychomotor speed. In CSE, striatal D2R binding showed a negative correlation with solvent exposure.

Interpretation

This is the first study in CSE showing pronounced disturbances within the FST circuitry that are related to the clinical findings and to exposure severity to solvents. The comparable, but milder, abnormalities within the FST circuitry in the exposed asymptomatic workers may imply a presymptomatic phase of CSE. Ann Neurol 2008
Synthesis and characterization of a series of SPEEK/TiO2 hybrid membranes for direct methanol fuel cell
Authors: Dou Zhiyu , Zhong Shuangling , Zhao Chengji , Li Xianfeng , Fu Tiezhu , Na Hui
Published: April 2008

Through sol‐gel reactions, a series of sulfonated poly(ether ether ketone) (SPEEK)/TiO2 hybrid membranes with various contents of nano‐sized TiO2 particles were prepared and characterized. It was found that with the increasing of the TiO2 contents in the hybrid membranes, the water uptake and water retention increased. Meanwhile, the introduction of inorganic particles reduced the methanol permeability. The proton conductivity was enhanced by introduction of hydrophilic inorganic particles into the SPEEK membranes, which might be an effective approach to increase the working temperature of PEM. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of di‐n‐dodecyl phosphate on the transesterification reaction in a poly(butylene terephthalate)/polycarbonate blend
Authors: Lei Caihong , Chen Dahua
Published: April 2008

The transesterification behavior of a poly(butylene terephthalate) (PBT)/polycarbonate (PC) blend with the addition of di‐n‐dodecyl phosphate was studied with differential scanning calorimetry (DSC) and infrared spectroscopy. The effects of triphenyl phosphate (TPP) and di‐n‐dodecyl phosphate on the suppression of transesterification were compared. The differences in the crystallization and melting temperatures during the two heating and cooling cycles in the DSC measurements were lower than those of the virgin PBT/PC blend, and di‐n‐dodecyl phosphate inhibited the formation of a random copolyester but did not suppress the formation of a block copolyester. The crystallization temperature of the PBT/PC blend in the presence of di‐n‐dodecyl phosphate was higher than that of the blend in the presence of TPP. Di‐n‐dodecyl phosphate was thus more effective than TPP in the inhibition of transesterification between PBT and PC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.
Mechanical and morphological characteristics of poly(vinyl alcohol)/chitosan hydrogels
Authors: Mathews D. T. , Birney Y. A. , Cahill P. A. , McGuinness G. B.
Published: April 2008

The effect of freeze–thaw cycles and chitosan type (water‐soluble or insoluble) on the morphological and mechanical characteristics of poly(vinyl alcohol) (PVA)/chitosan hydrogels was investigated with scanning electron microscopy (SEM), uniaxial testing, and a biaxial tubular vessel inflation experiment. SEM images showed that although multiple freeze–thaw cycles had no significant effect on pore size for PVA hydrogels without chitosan, both types of PVA–chitosan hydrogel developed a more porous structure with a greater distribution of pore size. Uniaxial mechanical tests demonstrated decreasing elasticity for successive freeze–thaw cycles within a range comparable to porcine aortic tissue. A conditioning effect, which modified the elastic response of the hydrogels after the first loading cycle, was also shown. Coefficients for hyperelastic material models were determined for the PVA–chitosan (water‐soluble) hydrogels. The internal pressurization and axial extension of a tubular vessel within the physiological range was investigated experimentally and compared with the predictions of a numerical model. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Formation of porous PLGA scaffolds by a combining method of thermally induced phase separation and porogen leaching
Authors: Yang Yanfang , Zhao Jin , Zhao Yunhui , Wen Liang , Yuan Xiaoyan , Fan Yubo
Published: April 2008

A novel method for the fabrication of porous poly(L‐lactide‐co‐glycolide) (PLGA) scaffolds by combining thermally induced phase separation and porogen leaching is presented in this article. Big pores with about 75–400 μm diameters in the obtained scaffolds were generated by the porogen, sucrose particles, while small pores with diameters less than 20 μm induced via phase separation. Extraction of the solvent, chloroform by ethanol at cool temperatures could reduce the scaffold toxicity. Effects of PLGA concentration, freezing temperature, volume fraction of porogen, and introduction of β‐tricalcium phosphate (β‐TCP) on morphology, porosity, and compressive properties of the scaffolds were systematically discussed. Results showed that the size of small pores decreased by decreasing the polymer concentration and reducing the freezing temperature, whereas the interconnectivity of the scaffolds was improved by increasing the porogen fraction. The compressive modulus and strength were significantly lowered by increasing the scaffold porosity, that is, by increasing porogen fraction, or decreasing the polymer concentration, or reducing the freezing temperature. Addition of β‐TCP into the scaffolds did not influence the compressive modulus significantly but tended to decrease the compressive strength. The obtained scaffolds with diverse pore sizes would be potentially used in bone tissue engineering. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Interphase modeling of copper‐epoxy particulate composites subjected to static and dynamic loading
Authors: Papanicolaou G. C. , Xepapadaki A. G. , Kotrotsos A. , Mouzakis D. E.
Published: April 2008

In this investigation, the static and dynamic behavior of copper‐filled epoxy particulate composites has been experimentally studied. The influence of particle‐weight fraction (0–25%), on the static behavior and filler concentration, temperature and frequency on the dynamic behavior of the mentioned particulate composites was thoroughly studied. Experimental results for the static three‐point bending modulus were compared with respective theoretical predictions derived from that existing in literature semiempirical models. Results were also compared with predictions derived by the application of the interphase model previously developed by the first author for the evaluation of the elastic modulus in particulate composites, taking into account the effect of filler‐matrix adhesion. It was found that the predicted values as derived from the application of the interphase model were in better agreement with experimental findings when compared with respective predictions derived from other models. Polymer‐filler degree of adhesion was also studied by applying the Turcsànyi model. Extended SEM investigations and DMA tests were also made to support both experimental and theoretical findings. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effects of vinyltrimethoxy silane on thermal properties and dynamic mechanical properties of polypropylene–wood flour composites
Authors: Bouza Rebeca , Lasagabaster Aurora , Abad María José , Barral Luis
Published: April 2008

The viability of vinyltrimethoxy silane was investigated as a coupling agent for the manufacture of wood–plastic composites (WPC). The effect of silane pretreatment of the wood flour on the thermal and the dynamic mechanical properties and thermal degradation properties of the composites were studied. Moreover, the effect of organosilane on the properties of composites was compared with the effect of maleated polypropylene (MAPP). DSC studies indicated that the wood flour acts as a PP‐nucleating agent, increasing the PP crystallization rate. In general, pretreatment with small amounts of silane improved this behavior in all the WPCs studied. Thermal degradation studies of the WPCs indicated that the presence of wood flour delayed degradation of the PP. Silane pretreatment of the wood flour augmented this effect, though without significantly affecting cellulose degradation. Studies of dynamic mechanical properties revealed that the wood flour (at up to 30 wt %) increased storage modulus values with respect to those of pure PP; in WPCs with a higher wood flour amount, there was no additional increase in storage modulus. Pretreatment of the wood flour with silane basically had no effect on the dynamic mechanical properties of the WPC. These results show that with small amounts of vinyltrimethoxy silane similar properties to the MAPP are reached. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Thermal characterisation of photo‐oxidized HDPE/Mater‐Bi and LDPE/Mater‐Bi blends buried in soil
Authors: Moriana‐Torró R. , Contat‐Rodrigo L. , Santonja‐Blasco L. , Ribes‐Greus A.
Published: April 2008

Blends of high and low density polyethylene with a commercial biodegradable material (Mater‐Bi) were subjected to an accelerated soil burial test. A set of samples was previously photo‐oxidized to evaluate the effects of UV‐irradiation on the degradation in soil process of these blends. Thermogravimetric as well as calorimetric analysis were performed to study the biodegradation, photo‐degradation and their synergetic effects. Differential scanning calorimetry was carried out to analyze the morphological changes as a consequence of the photo‐oxidation process. UV‐irradiation slightly modifies the crystalline content of HDPE/Mater‐Bi blends, increasing the heterogeneity of this blend. Criado master curves were plotted to analyses the degradation kinetic model. Broido and Coats‐Redfern methods have been used for calculating the Ea of the thermal decomposition mechanisms. Thermogravimetric results reveal that noncomplexed starch is more affected by biodegradation than the polyethylene matrix and the starch/EVOH complexes chains from Mater‐Bi. However, the effects of both photo‐oxidation and biodegradation processes on the thermal decomposition of Mater‐Bi is influenced by the polymeric matrix used. Previous photo‐oxidation finds to slow down the degradative effects caused by the soil burial test on the HDPE/Mater‐Bi blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis and characterization of new methacrylate‐type hydrogels containing 2‐tert‐butylamino ethyl groups for sorption purposes
Authors: Bayramgil Nursel Pekel
Published: April 2008

Crosslinked poly[2‐(tert‐butylamino)ethyl methacrylate] (PtBAEMA) hydrogels were synthesized by 60Co‐γ‐radiation‐initiated simultaneous polymerization and crosslinking of 2‐(tert‐butylamino)ethyl methacrylate in bulk and in aqueous solutions. The results showed that the gelation percentage decreased with increasing water content. The structural and thermal characterizations of the hydrogels were accomplished with several techniques, including Fourier transform infrared spectroscopy, swelling measurements, thermogravimetry, and differential scanning calorimetry. The effects of time, pH, temperature, and ionic strength on the swelling behavior were also investigated. Swelling equilibrium was attained in 2–3 days. PtBAEMA hydrogels originally swelled to 350% (by volume) in deionized water, but this value reached 3000% around pH 2.0. PtBAEMA hydrogels were reversibly affected by the change in temperature within the temperature range of 4–70°C. The swelling ratios of the gels decreased with increasing ionic strength. As a result, PtBAEMA hydrogels show stimuli‐responsive properties depending on the characteristics of the environment, and they are being considered for adoption as some kind of carrying material for separation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
The application of cell‐based label‐free technology in drug discovery
Authors: Xi Biao , Yu Naichen , Wang Xiaobo , Xu Xiao , Abassi Yama
Published: April 2008

Cell‐based assays are an important part of the drug discovery process allowing for interrogation of targets and pathways in a more physiological setting compared to biochemical assays. One of the main hurdles in the cell‐based assay field is to design sufficiently robust assays with adequate signal to noise parameters while maintaining the inherent physiology of the pathway or target being investigated. Conventional label and reporter‐based cell assays may be more prone to artifacts due to considerable manipulation of the cell either by the label or over‐expression of targets or reporter proteins. Cell‐based label‐free technologies preclude the need for cellular labeling or over‐expression of reporter proteins, utilizing the inherent morphological and adhesive characteristics of the cell as a physiologically relevant and quantitative readout for various cellular assays. Furthermore, these technologies utilize non‐invasive measurements allowing for time resolution and kinetics in the assay. In this article, we have reviewed the various label‐free technologies that are being used in drug discovery settings and have focused our discussion on impedance‐based label‐free technologies and its main applications in drug discovery.
Identification of optimal measurement sets for complete flux elucidation in metabolic flux analysis experiments
Authors: Chang YoungJung , Suthers Patrick F. , Maranas Costas D.
Published: April 2008

Metabolic flux analysis (MFA) methods use external flux and isotopic measurements to quantify the magnitude of metabolic flows in metabolic networks. A key question in this analysis is choosing a set of measurements that is capable of yielding a unique flux distribution (identifiability). In this article, we introduce an optimization‐based framework that uses incidence structure analysis to determine the smallest (or most cost‐effective) set of measurements leading to complete flux elucidation. This approach relies on an integer linear programming formulation OptMeas that allows for the measurement of external fluxes and the complete (or partial) enumeration of the isotope forms of metabolites without requiring any of these to be chosen in advance. We subsequently query and refine the measurement sets suggested by OptMeas for identifiability and optimality. OptMeas is first tested on small to medium‐size demonstration examples. It is subsequently applied to a large‐scale E. coli isotopomer mapping model with more than 17,000 isotopomers. A number of additional measurements are identified leading to maximum flux elucidation in an amorphadiene producing E. coli strain. Biotechnol. Biotechnol. Bioeng. 2008;100: 1039–1049. © 2008 Wiley Periodicals, Inc.
Practical identifiability of biokinetic parameters of a model describing two‐step nitrification in biofilms
Authors: Brockmann D. , Rosenwinkel K.‐H. , Morgenroth E.
Published: April 2008

Parameter estimation and model calibration are key problems in the application of biofilm models in engineering practice, where a large number of model parameters need to be determined usually based on experimental data with only limited information content. In this article, identifiability of biokinetic parameters of a biofilm model describing two‐step nitrification was evaluated based solely on bulk phase measurements of ammonium, nitrite, and nitrate. In addition to evaluating the impact of experimental conditions and available measurements, the influence of mass transport limitation within the biofilm and the initial parameter values on identifiability of biokinetic parameters was evaluated. Selection of parameters for identifiability analysis was based on global mean sensitivities while parameter identifiability was analyzed using local sensitivity functions. At most, four of the six most sensitive biokinetic parameters were identifiable from results of batch experiments at bulk phase dissolved oxygen concentrations of 0.8 or 5 mg O2/L. High linear dependences between the parameters of the subsets ${\rm (}K_{{\rm O}_{\rm 2} {\rm ,AOB}} {\rm ,}\,\mu _{{\rm AOB}} {\rm )}$ and ${\rm (}K_{{\rm O}_{\rm 2} {\rm ,NOB}} {\rm ,}\,\mu _{{\rm NOB}} {\rm )}$ resulted in reduced identifiability. Mass transport limitation within the biofilm did not influence the number of identifiable parameters but, in fact, decreased collinearity between parameters, especially for parameters that are otherwise correlated (e.g., µAOB and $K_{{\rm O}_{\rm 2} {\rm ,AOB}} $, or µNOB and $K_{{\rm O}_{\rm 2} {\rm ,NOB}} $). The choice of the initial parameter values had a significant impact on the identifiability of two parameter subsets, both including the parameters µAOB and $K_{{\rm O}_{\rm 2} {\rm ,AOB}} $. Parameter subsets that did not include the subsets µAOB and $K_{{\rm O}_{\rm 2} {\rm ,AOB}} $ or µNOB and $K_{{\rm O}_{\rm 2} {\rm ,NOB}} $ were clearly identifiable independently of the choice of the initial parameter values. Biotechnol. Bioeng. 2008;101: 497–514. © 2008 Wiley Periodicals, Inc.
A new device to close secundum atrial septal defects: First clinical use to close multiple defects in a child
Authors: Halabi Ali , Hijazi Ziyad M.
Published: April 2008

Transcatheter device closure of secundum atrial septal defects (ASD) has become an accepted treatment modality. Currently, the only device that can be used for large defects is the Amplatzer Septal Occluder. We report on a new device (Occlutech Figulla), to close multiple ASDs in a child with two large defects using 12 and 15 mm devices. © 2008 Wiley‐Liss, Inc.