bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphometric observations on three populations of Schizaphis graminum (Rondani), a main wheat aphid pest in Brazil
Authors: Rubin-de-Celis Verônica E. , Gassen Dirceu N. , Callegari-Jacques Sídia M. , Valente Vera L. S. , Oliveira Alice K.
Published: November 2006

The green aphid Schizaphis graminum (Rondani) is an important pest of Graminae. Samples of this aphid were collected at three environmentally distinct Brazilian localities, Passo Fundo (RS), Jaguariuna (SP) and Dourados (MS). Alatae and apterous viviparous forms were reared on the BR-35 wheat (Triticum aestivum) strain under controlled laboratory conditions and studied as to their variability in measures of body size and production of progeny. Univariate (ANOVA) and multivariate (canonical discriminant functions) techniques were used to evaluate differences among the three populations. Conspicuous differences between populations were observed in the length of five structures of the alatae and eight of the apterous forms, as well as in offspring production. The greatest dispersion in the length of general structures of the individuals obtained by the canonical discriminant function was for Passo Fundo, where climatic conditions are more severe and where aphids cause the most serious damage to wheat crop.
Nonpreference of the lace bug Leptopharsa heveae Drake & Poor (Heteroptera: Tingidae) for rubber tree clones
Authors: Lara Fernando M. , Tanzini Marcel R.
Published: November 2006

To determine the resistance of rubber tree clones (Hevea brasiliensis) to Leptopharsa heveae Drake and Poor (Heteroptera: Tingidae) a trial was held in Itiquira, MT, in 1994/95 by comparing the following clones: AVROS 2037, Fx 4037, GT 1, HARBEL, IAC 207, IAN 4493, IAN 717, IAN 873, RO 38, and RO 46. Free choice and no choice trials involving preference for oviposition and feeding were carried out under field and laboratory conditions. The symptoms caused by the insects, number of excrements, number of eggs/female/leaflet, mortality rate, and number of insects/leaflet were scored. The results showed that clones Fx 4037, RO 38 and RO 46 were resistant by nonpreference for feeding and oviposition, whereas GT and IAN 873 were the most susceptible.
Distribuição de Weibull como modelo de sobrevivência de Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae)
Authors: Reis Paulo R. , Haddad Marinéia L.
Published: November 2006

Utilizando-se a distribuição de Weibull como modelo de sobrevivência do ácaro predador Iphiseiodes zuluagai Denmark & Muma (Acari: Phytoseiidae), constatou-se que as fêmeas apresentaram maior longevidade do que os machos, e que tanto fêmeas quanto machos não acasalados apresentaram maior longevidade do que quando acasalados. A longevidade média de fêmeas não acasaladas foi de 27 dias e de acasaladas 23 dias. A longevidade dos machos não acasalados foi de 14 dias e dos acasalados 8 dias. Observou-se que, tanto para fêmeas como para machos, a taxa de mortalidade aumentou com o tempo. Entretanto, as estimativas dos parâmetros de forma foram muito próximos de 1, o que sugere que a taxa de mortalidade foi constante.
Efeito de espalhante-adesivo na eficiência dos acaricidas propargite e cyhexatin no controle do Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) em citros
Authors: Oliveira Carlos A. L. , Matuo Tomomassa , Santos Jr. José E. , Toledo Mílton C.
Published: November 2006

Embora espalhantes-adesivos sejam considerados importantes em pulverizações, existem dúvidas quanto à sua utilidade em pulverizações a alto volume quando o escorrimento é maior, como nas aplicações com equipamentos tipo pistola, para o controle de Brevipalpus phoenicis (Geijskes). Dois ensaios de campo foram conduzidos, em 1991 e 1994, em pomar de citros cv. Natal. As pulverizações foram realizadas com pulverizador tratorizado equipado com pistolas de alta pressão usando 18 l e 11 l de calda/planta, respectivamente. Efeitos dos espalhante-adesivo foi avaliado contando-se o número de ácaros antes e após a aplicação. Não se verificaram diferenças sensíveis na retenção do líquido pulverizado nas folhas de citros quando se adicionou o espalhante-adesivo à calda com propargite. Redução de até 95,6% na população do ácaro foi obsevada com o aumento na dosagem do propargite e de até 98,9% em relação de menor dosagem para o cyhexatin. Constatou-se que o espalhante-adesivo não melhorou a eficiência do cyhexatin, embora a somatória dos totais de ácaros, independentemente da dosagem e da formulação, tenha sido 50,1% menor com o uso de espalhante-adesivo.
Influência de variedades de cana-de-açúcar, incorporadas em dieta artificial, no desenvolvimento de Diatraea saccharalis (Fabr.) e no seu parasitismo por Cotesia flavipes (Cam.)
Authors: Boiça Jr. Arlindo L. , Lara Fernando M. , Bellodi Maria P.
Published: November 2006

Verificou-se a influência de duas variedades de cana-de-açúcar (Saccharum spp.), incorparados em dieta artificial, na forma de colmos triturados, no desenvolvimento de Diatraea saccharalis (Fabr.) e no parasitismo de Cotesia flavipes (Cam.). A variedade SP71-1081 foi menos adequada ao desenvolvimento de D. saccharalis comparada à SP71-3146, aumentando os períodos larval e pupal (dias) e, diminuindo o peso larval; não houve diferenças para as viabilidades larval e pupal e peso de pupa. Lagartas oriundas das dietas artificiais e lagartas alojadas no interior dos toletes das variedades de cana, foram igualmente parasitadas por C. flavipes. Lagartas criadas em dieta artificial contendo colmos triturados das variedades testadas, promoveram desenvolvimento semelhante de C. flavipes. A percentagem de parasitismo foi semelhante nas larvas criadas em dietas artificiais contendo colmos das variedades SP 71 - 1081 (84,0%) e SP 71-3146 (81,3%).
Illegal logging and local democracy: between communitarianism and legal fetishism
Authors: Azuela Antonio
Published: November 2006

The paper considers two major views of illegal logging: "Communitarian" and "legalistic". The former emphasizes the positive role of local communities and sees law enforcement programs as, at least potentially, counterproductive to environmental policy. While this perception fails to take the rule of law seriously, it shows the importance of local arrangements for sustainable use of forests. On the other hand, there is a view of deforestation that defines it only in juridical terms as 'illegal logging', without taking into account the variety and complexity of social problems at local level. The paper reviews some of the ways social sciences help us to overcome the limitations of both views. However, it also points at an issue that has not been sufficiently addressed by social disciplines: the question of local democracy. While most observers agree on the need of democratic institutions at the local level, there is not enough research and deliberation on the social conditions that make those institutions possible. This is a challenge for social sciences, due to the growing complexity of rural societies, a complexity that includes inter alia conflicts between owners and non-owners of natural resources, as well as the presence of 'external' social actors such as NGOs.
Use and misuse of the concepts of tradition and property rights in the conservation of natural resources in the atlantic forest (Brazil)
Authors: Castro Fábio de , Siqueira Andréa D. , Brondízio Eduardo S. , Ferreira Lúcia C.
Published: November 2006

The relationship between resource management, local populations, and property regimes has long puzzled researchers and policy-makers. The constant failure of conservation policy reliant upon privatization and statization, has led both policy makers and researchers to recognize the importance of customary practices to achieve conservation. Yet, the overemphasis on "traditional populations" and "collective property regimes" as the way to promote conservation can be misleading. In this paper, we discuss the debate on local populations and resource conservation in the Southeastern Atlantic Forest, Brazil. The analysis focuses on 1) the concept of traditional populations; 2) the complexity of overlapping property regimes; 3) the potential for a loose relationship between "traditional populations" and "collective property regimes," and; 4) the implications of this approach for "non-traditional populations." We conclude that the bias toward "tradition" and "collective property regimes" threatens the entire range of local communities along what might be called a traditional-non-traditional populations gradient.
Para uma imaginação sociológica da ecologia: uma análise do pensamento de Anthony Giddens
Authors: Lenzi Cristiano Luis
Published: November 2006

No presente texto tomamos a obra de Anthony Giddens para avaliar a forma pela qual a questão ecológica veio a ser incorporada pela teoria social. Giddens se tornou nas últimas décadas num dos grandes nomes das ciências sociais contemporâneas e, no decorrer dos últimos anos, passou a ter uma intervenção importante no cenário político com sua proposta de construção de uma Terceira Via. Ao mesmo tempo, ao longo desse período, muitos trabalhos das ciências sociais passaram a expressar também um interesse cada vez maior pelo tema ambiental. Um fenômeno que pode ser visto até mesmo nos próprios trabalhos de Giddens onde iremos encontrar uma referência permanente aos temas do risco, perigo, segurança e de conceitos como desenvolvimento sustentável, modernização ecológica e sociedade de risco. Em razão desse quadro geral, parece pertinente avaliarmos o que um teórico social como Giddens tem a nos dizer sobre a crise ecológica contemporânea. No texto procuramos mostrar como esse tema se entrelaça com três fases distintas do pensamento do autor. Ao final, avaliamos brevemente algumas críticas que são endereçadas ao seu trabalho.
Climacteric complaints among very low-income women from a tropical region of Brazil
Authors: Medeiros Sebastião Freitas de , Medeiros Márcia Marly Winck Yamamoto de , Oliveira Vivaldo Naves de
Published: November 2006

CONTEXT AND OBJECTIVE: Climacteric symptoms may vary between different countries and cultures. Socioeconomic factors and climate may be implicated. The aim of this study was to identify climacteric symptomatology among very low-income Brazilian women, living in a hot and humid region. DESIGN AND SETTING: This cross-sectional population-based study was conducted in Cuiabá, at Júlio Müller University Hospital, a tertiary institution. METHODS: The study enrolled 354 climacteric women. The variables analyzed were social class, symptomatology and abnormal concurrent conditions. The study was approved by the hospital's research ethics committee. RESULTS: Sixty-five percent of the participants (232/354) were very poor and had had little schooling. The number of symptoms per woman was 8.0 ± 5.7. Hot flushes, nervousness, forgetfulness and fatigue were each found in nearly 60.0%. Tearfulness, depression, melancholy and insomnia were also frequent. Sexual problems were reported by 25%. The most relevant concurrent abnormal conditions reported were hypertension (33.9%), obesity (26.5%), arthritis/arthrosis (15.0%) and diabetes mellitus (9.6%). Hot flushes were associated with tearfulness, nervousness and forgetfulness. CONCLUSION: Brazilian climacteric women of low income and low schooling present multiple symptoms. Vasomotor and psychosexual symptoms were the most prevalent disorders. Hot flushes were associated with nervousness, forgetfulness and tearfulness.
Effect of metabolic control on the in vitro proliferation of peripheral blood mononuclear cells in type 1 and type 2 diabetic patients
Authors: Foss-Freitas Maria Cristina , Foss Norma Tiraboschi , Donadi Eduardo Antonio , Foss Milton Cesar
Published: November 2006

CONTEXT AND OBJECTIVE: Diabetes mellitus is a clinical syndrome that frequently leads to the development of chronic complications and high susceptibility to infections. It is probably due to defective immunological defense, which may be related to metabolic control of the disease. The aim of this study was to evaluate the effect of metabolic control on immune-cell behavior in type 1 and type 2 diabetic patients. For this, the in vitro proliferation of peripheral blood mononuclear cells (PBMC) was analyzed in patients with inadequate and adequate metabolic control. DESIGN AND SETTING: Experimental/laboratory study at a university hospital. METHODS: Eleven type 1 and thirteen type 2 diabetic patients were studied, together with 21 healthy individuals divided in two groups (11/10), who were matched by sex and age with those diabetic patients. PBMC cultures stimulated with concanavalin-A (Con-A) were used to measure ³H-thymidine incorporation after 72 hours of cell culturing. For patients with inadequate metabolic control, culturing was performed on the first day of patient hospitalization and again after intensive treatment to achieve adequate control. RESULTS: The proliferation index for Con-A-stimulated cultures from type 1 diabetic patients was significantly greater than that for cultures from healthy individuals and type 2 diabetic patients, independent of metabolic control. A negative correlation between the proliferation cell index and body mass index and serum C-reactive protein levels was also observed. CONCLUSION: The increase in the proliferation capacity of type 1 diabetic T lymphocytes was probably not caused by hyperglycemia and/or insulinopenia related to inadequate metabolic control.
Kinetic lumping applied to wastewater treatment
Authors: Li Lixiong , Crain Neil , Gloyna Earnest F.
Published: November 2006

A key element in establishing efficient reactor designs for wastewater treatment is the ability to define, collectively rather than individually, the kinetic and mechanistic roles of numerous components in wastewater. One approach to resolve this complex problem is to consolidate the experimental data. Traditionally, the design and operation of waste treatment processes have relied on the use of lumped parameters, such as biochemical oxygen demand, chemical oxygen demand, total organic carbon, and total Kjeldahl nitrogen. In doing so, lumping has proven to be a practical tool for kinetic modeling. With the advent of theoretical foundations for kinetic lumping developed in the 1960s, there has been a growing interest in applying this methodology for modeling multicomponent mixtures. As an example, kinetic lumping was first successfully used for modeling the refining of complex hydrocarbon mixtures. These mathematical tools and proven lumping strategies are now available to systematically explore the use of lumped kinetic models for wastewater treatment systems. This study has demonstrated that existing kinetic lumping strategies can be adapted for modeling wastewater treatment processes. Specifically, kinetic lumping strategies and models suitable for wastewater treatment applications have been developed. Examples are provided to illustrate how to select and evaluate lumping schemes and how to calculate lumped rate constants involving reactions starting with single organic constituents and organic mixtures, subjected to hydrothermal oxidation (supercritical water oxidation). The application of kinetic lumping to traditional waste treatment processes is also demonstrated through discussion and examples involving aerobic and anaerobic biodegradation.
Numerical simulation of saltwater intrusion in a groundwater basin
Authors: Emekli Nusret , Karahanoğlu Nurkan , Yazicigil Hasan , Doyuran Vedat
Published: November 2006

The spatial and transient behavior of the coupled mechanism of saltwater and freshwater flow throughout the Erzin, Turkey, groundwater basin was analyzed to forecast the position of the interface under a particular set of recharge and discharge conditions. The density‐driven saltwater intrusion process was simulated with the use of a finite element model. Physical parameters, initial heads, and boundary conditions of the basin were defined on the basis of available field data, and an areal, steady‐state groundwater model was constructed to calibrate the observed head values corresponding to the initial development phase of the aquifer. Initial and boundary conditions determined from the areal calibration were used to evaluate the aquifer's dispersivities and the porosity in a steady‐state, cross‐sectional analysis. Consequently, the initial position of the salt concentration distribution was calibrated under steady‐state conditions. The initial concentration distribution was then marched through time under discharge and recharge conditions, and the present‐day position of the interface was predicted. In the cross‐sectional simulation, the saltwater front was predicted to move inland during the discharge period, whereas in the recharge period the heads were predicted to recover to their initial positions with no significant movement of saltwater. The present‐day distribution of salt concentrations was estimated via a 25‐year simulation. Results indicate that the width of the dispersion zone has increased during this period and the saltwater encroachment has gradually been slowed down, tending toward a new steady‐state position.
Use of centrifuge for pretreatment of combined wastewaters from a plasticizer manufacturing facility
Authors: Petrosky Curtis J. , Vidic Radisav D.
Published: November 2006

Wastewater generated by a chemical manufacturing facility required a significant reduction in the bis(2‐ethylhexyl) phthalate, di‐n‐octyl phthalate, and di‐n‐butyl phthalate ester concentration before discharge to a publicly owned treatment works (POTW). These three phthalate esters along with other esters and alcohols make up a dispersed phase in the wastewater that has lower density than water. Centrifugation was evaluated as a pretreatment process for the removal of the phthalate esters to within the effluent limits set by the POTW. The wastewater was treated by a fun‐scale commercial centrifuge at different operating conditions (effluent back pressure and flow rate) to determine the optimum conditions for phthalate ester removal. The results of this study suggest that the degree of phthalate esters removal is independent of wastewater flow rate and centrifuge effluent back pressure but depends solely on the stability of the phthalate ester emulsion that appears to be directly related to the concentration of emulsifying agent (sodium monoester salts) in the wastewater. Centrifugation provided better phthalate ester separation from the wastewater than gravity separation alone; however, the periodic occurrence of heavily emulsified phthalate esters in the wastewater necessitates the use of an equalization tank downstream of the centrifuge to consistently meet the effluent limit of 5.0 mg/L of the three phthalate esters. In addition to the wastewater effluent, the centrifuge produces a light‐phase effluent and a sludge effluent. The light‐phase effluent contains esters, alcohol, and water and can be recycled back to the ester facility for reprocessing into salable product. The sludge effluent contains a dilute concentration of solids with a significant amount of adsorbed phthalate esters. The phthalate esters can be separated from the solids into an oily layer under acidic conditions. The oily layer can then be removed by reprocessing the acidified solids stream in the centrifuge, thereby enabling the disposal of the solids with the treated wastewater. This integrated waste management process would eliminate the need for additional solids processing equipment.
Synthetic sludge: A physical/chemical model in understanding bioflocculation
Authors: Sanin F. Dilek , Vesilind P. Aarne
Published: November 2006

We postulate a mechanism for floc formation and demonstrate its feasibility by building synthetic sludge flocs. In this work, polystyrene latex particles of a size similar to bacteria are used to simulate individual bacteria; alginate, a polysaccharide, is used to simulate microbial extracellular polymers; and calcium ions are used as the bridging cations. Calcium and alginate are added at typical concentration ranges relative to the amount of microorganisms existing in wastewater treatment biological sludges. Flocs are formed almost instantly by the addition of calcium ions and are observed to be remarkably similar to the activated sludge flocs in physical appearance. Floc formation is faster at higher calcium concentrations. Higher alginate and calcium concentrations always ensure lower turbidities indicating better floc forming abilities. The results of this study indicate that formation of metal‐polymer complexes and polymer gelation are important means of flocculation. Because of similar concentration ranges of alginate and calcium in this study to extracellular polymers and calcium in activated sludge, these mechanisms of flocculation are suggested also to be the main mechanism of interaction during bioflocculation in activated sludge systems.
Kinetics of denitrification by Pseudomonas denitrificans under growth conditions limited by carbon and/or nitrate or nitrite
Authors: Kornaros M. , Zafiri C. , Lyberatos G.
Published: November 2006

Kinetic experiments were carried out for a pure culture of Pseudomonas denitrificans to develop a mathematical model that adequately describes denitrification under both carbon and nitrate or nitrite electron acceptor limited conditions. Denitrification was assumed to occur by the consecutive reduction of nitrates to nitrites and then to nitrogen gas without accumulation of intermediate gaseous products. The denitrification kinetics, assuming they are associated with cell growth, could be very well described by using Monod expressions with double substrate limitation (terminal electron acceptor and organic carbon). The kinetic parameters of the model were evaluated exclusively from batch experimental data. The proposed model is able to predict accurately the biomass growth, the nitrate and nitrite reduction rates, as well as the accumulation of nitrite‐nitrogen as an intermediate, due to nitrate inhibition on the nitrite reduction rate.
Development and Testing of Math Insight Software
Authors: Zucker Andrew A.
Published: November 2006

Computers running appropriate software hold great promise for teaching and learning mathematics. To this end, SRI International developed an integrated, computer-based problem solving environment called Math Insight that included interactive tools, such as a spreadsheet and dynamic geometric sketches, and professionally produced videos used to situate a wide variety of mathematics challenges. The developers envisioned that Math Insight would develop students' mathematics skills and their proficiency with computer-based tools, based on solving novel problems incorporated in the software. Evaluation data from teachers and students were positive. However, a number of factors worked against commercialization, including passage of the No Child Left Behind Act, a decrease in school technology funds, and a large decline in education software sales. Freely available mathematics applets and open source software are becoming an important alternative source of software for mathematics education. However, whatever software solutions are chosen, policymakers must be sure that they are part of a coherent education program.
Are We Using Technology for Learning?
Authors: Lowerison Gretchen , Sclater Jennifer , Schmid Richard F. , Abrami Philip C.
Published: November 2006

This study investigated the role that computer technology plays in transforming the learning process in higher education. Specifically, we looked at the relationship between computer-technology use, active learning, and perceived course effectiveness. The sample consisted of 1966 students in 81 graduate and undergraduate classes at a large, urban university. The survey categories were: 1) learner preferences; 2) course structure; 3) active learning; 4) time on task; 5) learning with technology; 6) perceived effectiveness of computer use; 7) context of computer use; and 8) overall perceived course effectiveness. Results suggest that there is a relationship between computer technology, active learning, and perceived course effectiveness. Students who use computer technology a lot appear to benefit the most from active learning.
Costs in searching for two targets: dividing search across target types could improve airport security screening
Authors: Menneer Tamaryn , Barrett Doug J. K. , Phillips Luke , Donnelly Nick , Cave Kyle R.
Published: November 2006

The cost of searching for two visual targets simultaneously was compared against two separate single‐target searches using exposure time and accuracy measures within a staircase procedure. Dual‐target search for all stimuli (colour, shape and orientation) exhibited a loss of accuracy for one target. For orientation and shape, this dual‐target cost in accuracy was extreme, with chance‐level performance on one target. For colour, dual‐target search exhibited an additional cost in search time, with search requiring a longer exposure than the summed time required for two single‐target searches. An additional search‐time cost was also found for orientation targets when irrelevant colour variation was added to the display. In conclusion, dual‐target search for dissimilar targets is accompanied by an accuracy cost. Furthermore, colour variation, whether task‐relevant or not, leads to an additional cost in processing speed. The results suggest that a divided‐effort strategy would improve performance in search tasks such as X‐ray baggage screening. Copyright © 2006 John Wiley & Sons, Ltd.
When accurate and inaccurate eyewitnesses look the same: a limitation of the ‘pop‐out’ effect and the 10‐ to 12‐second rule
Authors: Ross David F. , Benton Tanja Rapus , McDonnell Stephanie , Metzger Richard , Silver Christopher
Published: November 2006

Research has found support for a ‘pop‐out effect’ that occurs when witnesses who accurately identify a criminal from a lineup are faster and uses more automatic processing than inaccurate witnesses who misidentify a foil. We present evidence that this finding may not occur with biased lineups. Witnesses to a mock theft were asked to make a lineup identification and three types of witnesses were compared: (1) accurate witnesses who identified a thief, (2) inaccurate witnesses who misidentified a foil who was more similar looking to the thief than the other lineup foils and (3) inaccurate witnesses who misidentified a foil who was not more similar in appearance to the thief than the other lineup foils. Accurate witnesses who identified the thief and inaccurate witnesses who misidentified a foil more similar to the thief than the other lineup foils were indistinguishable; both were faster, used more automatic recognition processes and were more confident than inaccurate witnesses who identified other foils. Copyright © 2006 John Wiley & Sons, Ltd.
A state of high anxiety: how non‐supportive interviewers can increase the suggestibility of child witnesses
Authors: Almerigogna Jehanne , Ost James , Bull Ray , Akehurst Lucy
Published: November 2006

The present study examined the effects of state and trait anxiety on 8–11 years old children's susceptibility to misleading post‐event information. Participants' state and trait anxiety were measured, after which they watched an extract from a children's movie. They were then individually interviewed using either a supportive or a non‐supportive style. During the interviews, the children were asked 14 questions about the movie, seven of which were control and seven contained misleading information. After the interview, their state anxiety was measured again. Results showed that participants interviewed in a non‐supportive style were more likely to provide incorrect answers to misleading questions. Furthermore, participants who scored highly on both trait and post‐interview state anxiety measures more often responded incorrectly to misleading questions. Also, pre‐to post‐interview changes in state anxiety were correlated with more incorrect responses to misleading questions. Copyright © 2006 John Wiley & Sons, Ltd.
Passivity‐based control for stabilization, regulation and tracking purposes of a class of nonlinear systems
Authors: Travieso‐Torres Juan C. , Duarte‐Mermoud Manuel A. , Sepúleveda Diego I.
Published: November 2006

In this paper, a new passivity‐based control (PBC) scheme based on state feedback is proposed in order to solve tracking, regulation and stabilization problems for a class of multi‐input multi‐output (MIMO) nonlinear systems expressed in the normal form, with time‐invariant parameters and locally bounded reference weakly minimum phase. For the proposed control scheme two new different state feedbacks, one non‐adaptive for the case when the system parameters are assumed to be known and the other adaptive for the case of unknown parameters, are developed. For the adaptive case it is assumed that the unknown parameters appear linearly in the equations. Analysis of the transient behaviour of the proposed control schemes is presented through the simulation of two examples. Copyright © 2006 John Wiley & Sons, Ltd.
Prolonged survival of an HIV‐infected patient with plasmablastic lymphoma of the oral cavity
Authors: Panos George , Karveli Efthymia A. , Nikolatou Ourania , Falagas Matthew E.
Published: November 2006

Plasmablastic lymphoma is an aggressive subtype of diffuse large B‐cell lymphoma that is mainly observed in patients with the human immunodeficiency virus (HIV) infection, and it tends to arise in the oral cavity. We present a case of an HIV‐infected patient with plasmablastic lymphoma with prolonged survival. The 30‐yr‐old woman was found to have an oral lesion at the time of the diagnosis of HIV infection. Histological and immunochemical examination of biopsy of the oral lesion showed plasmablastic lymphoma (CD138+). She received two cycles of cyclophosphamide, vincristine, doxorubicin, and prednisolone (CHOP) that started 10 weeks after the initiation of antiretroviral therapy. The continuing pancytopenia and an adenoviral febrile infection did not permit further antineoplastic treatment. A gradual decrease of the oral lesion was noted after the second cycle of chemotherapy that led to the disappearance of the lesion 7 months later. The patient remains in complete remission 61 months after the diagnosis of plasmablastic lymphoma. Am. J. Hematol., 2007. © 2006 Wiley‐Liss, Inc.
Adherent leukocytes capture sickle erythrocytes in an in vitro flow model of vaso‐occlusion
Authors: Finnegan Eileen M. , Turhan Aslihan , Golan David E. , Barabino Gilda A.
Published: November 2006

Recent in vivo studies suggest that adherent leukocytes bind RBCs and contribute to the microvascular pathology that characterizes sickle cell disease (SCD). A parallel‐plate flow assay was used: to investigate the capture of RBCs by adherent neutrophils, monocytes, and T‐lymphocytes; to examine whether RBC capture is elevated in patients with SCD; and to determine whether hydroxyurea (HU) therapy affects these interactions. Four measures of cell–cell adhesion were used: adhesion of leukocytes to TNF‐α‐treated human umbilical vein endothelial cells (HUVECs), percent of adherent leukocytes that captured RBCs, number of RBCs captured per interacting leukocyte, and duration of RBC capture. Leukocyte subpopulations from sickle patients were more adherent to activated ECs and captured more RBCs per interacting leukocyte than the corresponding subpopulations from healthy controls. While HU did not affect leukocyte adhesion to activated ECs, it reduced the proportion of adherent leukocytes that captured RBCs, as well as the number of RBCs captured per neutrophil. T‐lymphocytes demonstrated elevated adhesion in all measures, and may be the leukocyte subpopulation whose behavior is most altered in SCD. Our findings suggest that neutrophils, monocytes, and T‐lymphocytes could all be involved in adhesive interactions with autologous RBCs in patients with SCD. Am. J. Hematol., 2007. © 2006 Wiley‐Liss, Inc.
Synthesis and properties of carboxymethyl cellulose‐graft‐poly(acrylic acid‐co‐acrylamide) as a novel cellulose‐based superabsorbent
Authors: Suo Aili , Qian Junmin , Yao Yu , Zhang Wanggang
Published: November 2006

A new cellulose‐based superabsorbent polymer, carboxymethyl cellulose‐graft‐poly(acrylic acid‐co‐acrylamide), was prepared by the free‐radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto carboxymethyl cellulose (CMC) in the presence of N,N′‐methylenebisacrylamide as a crosslinker with a redox couple of potassium persulfate and sodium metabisulfite as an initiator. The influences of reaction variables such as the initiator content, crosslinker content, bath temperature, molar ratio of AA to AM, and weight ratio of the monomers to CMC on the water absorbency of the carboxymethylcellulose‐graft‐poly(acrylic acid‐co‐acrylamide) copolymer were investigated. The copolymer's structures were characterized with Fourier transform infrared spectroscopy. The optimum reaction conditions were obtained as follows: the bath temperature was 50°C; the molar ratio of AA to AM was 3 : 1; the mass ratio of the monomers to CMC was 4 : 1; and the weight percentages of the crosslinker and initiator with respect to the monomers were 0.75 and 1%, respectively. The maximum water absorbency of the optimized product was 920 g/g for distilled water and 85 g/g for a 0.9 wt % aqueous NaCl solution. In addition, the superabsorbent possessed good water retention and salt resistance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1382–1388, 2007
Preparation and characterization of a thermoplastic poly(glycerol sebacate) elastomer by two‐step method
Authors: Liu Quanyong , Tian Ming , Ding Tao , Shi Rui , Feng Yuxing , Zhang Liqun , Chen Dafu , Tian Wei
Published: November 2006

A thermoplastic poly(glycerol sebacate) elastomer (TMPGS), prepared by a two‐step method for the first time, is characterized in the present work. First, non‐crosslinked poly(glycerol sebacate) (PGS) prepolymers at the 1 : 1 molar ratio of glycerol to sebacic acid were synthesized through a condensation reaction. Second, TMPGSs were achieved through prepolymers that continued to react after the addition of more sebacic acid at a total molar ratio of 2 : 2.5 (glycerol/sebacic acid). The swelling experiments demonstrated that its crosslinking density was low and that it was composed of sol and gel. Compared with our previous results, the content of sol decreased but still reached >60%. Differential scanning calorimetry (DSC) studies demonstrated that TMPGS was crystallizable and had a glass transition temperature below −20°C, but at close to 37°C, its state altered and became almost amorphous. It was explained that both the semi‐interpenetrated polymer networks composed of sol and gel and the crystal regions imparted thermoplasticity to the elastomer. Finally, the in vitro degradation tests illuminated the degradation characteristic of TMPGS in 37°C phosphate buffered saline solution (pH = 7.4). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1412–1419, 2007
Investigation of thermal behavior of poly(2‐hydroxyethyl methacrylate‐co‐itaconic acid) networks
Authors: Çaykara Tuncer , Özyürek Cengiz , Kantoğlu Ömer
Published: November 2006

The thermal behavior of poly(2‐hydroxyethyl methacrylate) [PHEMA] homopolymer and poly(2‐hydroxyethyl methacrylate‐co‐itaconic acid) [P(HEMA/IA)] copolymeric networks synthesized using a radiation‐induced polymerization technique was investigated by differential scanning calorimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The glass‐transition temperature (Tg) of the PHEMA homopolymer was found to be 87°C. On the other hand, the Tg of the P(HEMA/IA) networks increased from 88°C to 117°C with an increasing amount of IA in the network system. The thermal degradation reaction mechanism of the P(HEMA/IA) networks was determined to be different from the PHEMA homopolymer, as confirmed by thermogravimetric analysis. It was observed that the initial thermal degradation temperature of these copolymeric networks increased from 271°C to 300°C with IA content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1602–1607, 2007
Supercritical carbon dioxide extraction in membrane formation by thermally induced phase separation
Authors: Zhang Chun‐Fang , Zhu Bao‐Ku , Ji Gen‐Liang , Xu You‐Yi
Published: November 2006

In this study, a novel and environmentally friendly extracting method, supercritical carbon dioxide (SC‐CO2) extraction, was investigated in the thermally induced phase separation (TIPS) process for making microporous membranes. In the SC‐CO2 extraction, the effects of extraction time, pressure, and temperature on the extraction fraction, membrane morphology, and membrane performance were investigated. It was concluded that with extraction conditions of 18 MPa, 35°C and 2 h, the porous membrane had the highest extraction fraction. There was a close relationship between membrane performance and the extraction conditions of SC‐CO2, and it is possible to tailor membrane performance through the choice of extraction conditions. Compared with traditional solvent extraction, a dry membrane treated by SC‐CO2 extraction has much less shrinkage and greater water permeability, whereas the degree of crystallization of a membrane extracted by SC‐CO2 is slightly greater than that extracted by ethanol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1632–1639, 2007
Structural interactions of globular proteins—Bovine serum albumin, egg albumin, and lysozyme, in aqueous medium, elucidated with molar volumes, viscosities, energy functions, and IR spectra from 293.15 to 303.15 K
Authors: Singh Man
Published: November 2006

Densities (ρ), apparent molar volumes (Vϕ), viscosities (η), and IR spectra on 0.0010–0.0018% aqueous solutions of bovine serum albumin (BSA), egg albumin (E‐Alb), and lysozyme at an interval of 0.0004% and at temperatures from 293.15, 298.15, and 303.15 K have obtained. The free energy (ΔG), entropy (ΔS), and enthalpy (ΔH) data with compositions and temperatures are calculated from the values of the flow velocity (vf) of viscous flow, which decrease with temperature. The densities decrease with concentrations and temperatures except BSA, and the Vϕ values slightly increase with concentrations for BSA and lysozyme, which depict structural reorientations and transition states of protein molecules with increase in viscosities and decrease in reduce viscosities. The reduce viscosities at 293.15 K for BSA, E‐Alb, and lysozyme are noted positive, and for BSA and lysozyme remain positive at 298.15 and 303.15 K, whereas for E‐Alb it is negative. Activation energies (E*) for lysozyme remain almost constant, and are higher than those of the BSA and E‐Alb, respectively, also slightly higher E* values for the BSA than those of the E‐Alb at 293.15 and 298.15, and lower than of the E‐Alb at 303.15 K, are observed elucidating greater structural interactions for BSA at lower while weaker at temperatures. Stretching frequencies of amide (NHCO), NH, CO, and CH groups of proteins are noted from IR spectra with broader stretching frequencies for NH. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1420–1429, 2007
Layer‐by‐layer films based on charge transfer interaction of ϕ‐conjugated poly(dithiafulvene) and incorporation of gold nanoparticles into the films
Authors: Wang Xiaqin , Naka Kensuke , Wang Chaosheng , Itoh Hideaki , Uemura Takashi , Chujo Yoshiki
Published: November 2006

Layer‐by‐layer (LBL) self‐assembled ultrathin films were prepared via consecutively alternating immersion of substrates into solutions of electron donor, poly(dithiafulvene) (PDF), and electron acceptor, poly(hexanyl viologen) (6‐VP). The charge transfer (CT) interaction formed at solid–liquid interfaces between the backbones of the electron acceptor and donor polymers was the driving force of the alternative deposition. The sandwich heterostructure of the LBL film led to electrical anisotropy in the directions parallel and perpendicular to the film surfaces. Incorporation of gold nanoparticles into the LBL films was investigated by reducing gold ions with the PDF layers already deposited on the film surfaces, or depositing PDF‐protected gold colloidal solution as the electron donor layers directly. The influence of the gold nanoparticles on the electrical anisotropy of the LBL films was also illustrated in this research. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1608–1615, 2007
Grafting of vinyl acetate onto chitosan and biocidal activity of the graft copolymers
Authors: Elkholy Said , Khalil Khaled D. , Elsabee Maher Z. , Eweis Mohamed
Published: November 2006

Modification of chitosan by grafting with vinyl acetate (VAc) was carried out using potassium persulfate and sodium bisulfite as redox initiators. The effect of monomer, initiator concentration, time, and temperature was studied. The grafted samples were subjected to alkaline hydrolysis and the polyvinyl acetate (PVAc) branches were consequently partially converted into polyvinyl alcohol (PVAl) graft, which showed enhanced swelling in water. The graft copolymers showed a better dye uptake for both acidic and basic dyes. Chitosan/VAc and chitosan/VAl copolymers were both subjected to reaction with dimethyl sulfate in alkaline medium to yield quaternized copolymers. The antifungal behavior of chitosan and its graft copolymers was investigated in vitro on the mycelial growth, sporulation, and germination of conidia or sclerotia of the following sugarbeet: Beta vulgaris pathogens isolated in Egypt, Rhizoctonia solani Kühn (AG2‐2) Sclerotium rolfsii Sacc. and Fusarium solani (Mart.) Sacc. These polymers were also screened against several fungi and it has been found that grafting with polyvinyl alcohol branches enhances the antifungal activity dramatically. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1651–1663, 2007
Electrospinning of cellulose‐based nanofibers
Authors: Frenot Audrey , Henriksson Maria Walenius , Walkenström Pernilla
Published: November 2006

Cellulose derivatives of carboxymethyl cellulose sodium salt (CMC), hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and enzymatically treated cellulose have been electrospun, and the microstructure of the resulting nanofibers has been analyzed by scanning electron microscopy (SEM). Before electrospinning, the solutions were characterized by viscometry and surface tension measurements, and the results were correlated with spinnability. Four different CMC derivatives, varying in molecular weight (Mw), degree of substitution (DS), and substitution pattern, have been electrospun in mixtures with poly(ethylene oxide) (PEO), and nanofibers of various characteristics have formed. The CMC‐based nanostructures, i.e., the nonwoven sheet and individual nanofibers, proved to be independent of Mw and DS but largely dependent on the substitution pattern. The nonwoven sheets varied in homogeneity, and beads appeared on the individual fibers. Depending on the chemical nature of the CMC, the extraction of PEO resulted in pure CMC nanostructures of varying appearance, indicating that the distribution of PEO and CMC in the nanofibers also varied. Two different HPMC derivatives, varying in DS, were electrospun into nanofibers. Homogeneous nonwoven sheets based on nanofibers of similar appearance are formed, independent of the substitution content of the HPMC sample. Preliminary fibers were obtained from enzymatically treated cellulose in a solvent system based on lithium chloride dissolved in dimethyl acetamide (LiCl: DMAc). © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1473–1482, 2007
Polyamidoamine dendrimers as curing agents: The optimum polyamidoamine concentration selected by dynamic torsional vibration method and thermogravimetric analyses
Authors: Cheng Yiyun , Xu Tongwen , He Pingsheng
Published: November 2006

Polyamidoamine (PAMAM) dendrimers were investigated as curing agents in bisphenol A epoxy resin systems. The cure behavior of epoxy resin/PAMAM at varying components was investigated by a dynamic torsional vibration method (DTVM); the thermal behavior of the materials was characterized by means of thermogravimetric (TGA) analyses. The DTVM results show that 10/100 parts of the resin (phr) PAMAM was the optimum concentration for 1.0, 3.0, and 5.0 G PAMAM dendrimers/resin systems in our experiment. Also, the TGA results agreed with the conclusions made by the DTVM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1430–1434, 2007
Synthesis and surface properties of polystyrene‐graft‐poly(ethylene glycol) copolymers
Authors: Feng Li‐Bang , Zhou Shu‐Xue , You Bo , Wu Li‐Min
Published: November 2006

Polystyrene‐graft‐poly(ethylene glycol) copolymers (PS‐g‐PEG) were successfully synthesized using the “grafting‐through” method. The graft copolymers and the surface properties of their coats were characterized by1H‐NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), static contact angle measurement, and atomic force microscopy (AFM). Both DSC and TEM indicated that the graft copolymers had a microphase separated structure. AFM showed the microphase separated structure also occurred at the coat surface, especially at high PEG content, which could also be indirectly confirmed by the XPS and contact angle results. The formation mechanism of the microphase separated structure was discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1458–1465, 2007
Systematic investigations of fatigue crack growth behavior of a PE‐HD pipe grade in through‐thickness direction
Authors: Balika W. , Pinter G. , Lang R. W.
Published: November 2006

Fatigue crack growth (FCG) experiments were performed on a commercial high‐density polyethylene (PE‐HD) pipe grade. To investigate the influence of different specimen types on FCG results, tests were conducted using compact tension (CT) specimens and cracked round bars (CRB). The effects of frequency and R‐ratio on FCG behavior were also studied. Furthermore, FCG tests were interrupted in the region of stable crack propagation. The crack front and the front of the process zone ahead of the crack were systematically characterized via microscopic methods in the thickness direction of the specimen. The experimental data are employed to study the mechanisms of process zone development and to determine the effective crack length by compliance relationships. This detailed information allows modeling FCG in PE‐HD at various positions in the thickness direction of the specimen. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:1745–1758, 2007
Diffusion rates and the role of diffusion in solid propellant rocket motor adhesion
Authors: Grythe Kai F. , Hansen Finn K.
Published: November 2006

Diffusion rates can give important information for the adhesion process across the bondline between insulation and propellant in solid propellant rocket motors. Diffusion coefficients of low molecular weight species such as crosslinkers and plasticizers have been measured by the weight of uptake method in polymer materials that are candidates for propellant contact. The materials were EPDM insulation sheets and “liners,” based on HTPB, HTPE, or GAP, and with different degrees of particle filling. Plots of relative mass gain as a function of the square root of time showed good linearity up to 20–50% weight increase and the diffusion coefficients could thus be determined with good accuracy. The diffusion coefficients for the low molecular weight isocyanates and plasticizers in these materials vary between 10−11 and 10−17 m2 s−1, dependent on material types and particle filling. In most cases, the results can be explained by the solubility parameters of the organic liquids and polymers. For the particle filled samples, the diffusion coefficients decrease with increasing degree of particle filling, and the decrease is faster than predicted by the Maxwell–Fricke or the Keller models for arrays of smooth spheres. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1529–1538, 2007