bluuebunny/crossref_metadata_2025 huggingface dataset:
Gastric versus post-pyloric feeding: a systematic review
Authors: Marik Paul E , Zaloga Gary P
Published: May 2003

Background

Our objective was to evaluate the impact of gastric versus post-pyloric feeding on the incidence of pneumonia, caloric intake, intensive care unit (ICU) length of stay (LOS), and mortality in critically ill and injured ICU patients.

Method

Data sources were Medline, Embase, Healthstar, citation review of relevant primary and review articles, personal files, and contact with expert informants. From 122 articles screened, nine were identified as prospective randomized controlled trials (including a total of 522 patients) that compared gastric with post-pyloric feeding, and were included for data extraction. Descriptive and outcomes data were extracted from the papers by the two reviewers independently. Main outcome measures were the incidence of nosocomial pneumonia, average caloric goal achieved, average daily caloric intake, time to the initiation of tube feeds, time to goal, ICU LOS, and mortality. The meta-analysis was performed using the random effects model.

Results

Only medical, neurosurgical and trauma patents were enrolled in the studies analyzed. There were no significant differences in the incidence of pneumonia, percentage of caloric goal achieved, mean total caloric intake, ICU LOS, or mortality between gastric and post-pyloric feeding groups. The time to initiation of enteral nutrition was significantly less in those patients randomized to gastric feeding. However, time to reach caloric goal did not differ between groups.

Conclusion

In this meta-analysis we were unable to demonstrate a clinical benefit from post-pyloric versus gastric tube feeding in a mixed group of critically ill patients, including medical, neurosurgical, and trauma ICU patients. The incidences of pneumonia, ICU LOS, and mortality were similar between groups. Because of the delay in achieving post-pyloric intubation, gastric feeding was initiated significantly sooner than was post-pyloric feeding. The present study, while providing the best current evidence regarding routes of enteral nutrition, is limited by the small total sample size.
Correlation between inflammatory response and markers of neuronal damage in coronary revascularization with and without cardiopulmonary bypass
Authors: Mazzone Annamaria , Gianetti Jacopo , Picano Eugenio , Bevilacqua Stefano , Zucchelli Giancarlo , Biagini Andrea , Glauber Mattia
Published: May 2003

Off-pump coronary artery bypass graft (CABG) surgery may reduce the inflammatory response and the neuronal damage associated with conventional CABG on cardio-pulmonary bypass. The purpose of this study was to explore the protective effect of off-pump surgery by assessing plasma inflammatory and neuronal injury markers. Forty-one patients with coronary artery disease undergoing elective CABG were examined: 21 on-pump (Group I) and 20 off-pump (Group II). The perioperative release of interleukin-2 receptor (IL-2r), IL-6, tumor necrosis factor-alpha, S-100 protein (S-100) and neuron-specific enolase (NSE) were measured. Postoperative peak values of NSE (p B /0.001) and S-100 (p B /0.05) were significantly lower in Group II. IL-6 showed significantly lower values in off-pump patients (p B /0.001). A significant correlation was found between NSE and IL-6 (p B /0.001). In conclusion, off-pump surgery reduces the inflammatory response as well as the perioperative release of neuronal damage markers. Correlation between inflammatory activation and neuronal markers may suggest a link between inflammation and release of markers of neuronal clinical and subclinical injury.
A review of anti-inflammatory strategies in cardiac surgery
Authors: Asimakopoulos George , Gourlay Terence
Published: May 2003

It is generally accepted that cardiac surgery is frequently associated with the development of systemic inflammatory response. This phenomenon is very variable clinically, and can be detected by measuring plasma concentrations of certain inflammatory markers. Complement component, cytokines and adhesion molecules are examples of these markers. Systemic inflammation can be potentially damaging to major organs. Several anti-inflammatory strategies have been used in recent years, aiming to attenuate the development of systemic inflammatory response. This article summarizes recently published literature concerning the use of anti-inflammatory techniques and pharmacological agents in cardiac surgery. In particular, the anti-inflammatory effects of off-pump surgery, leukocyte filtration, corticosteroids, aprotinin, phosphodiesterase inhibitors, dpoexamine, H2 antagonists and ACE inhibitors are reviewed. The overall conclusion is that although certain strategies reduce plasma levels of inflammatory mediators, convincing evidence of significant clinical benefits is yet to come.
The role of leukocyte depletion in ex vivo evaluation of pulmonary grafts from (non-)heart-beating donors
Authors: Rega Filip R , Vandezande Eddy J , Jannis Nicole C , Verleden Geert M , Lerut Toni E , Van Raemdonck Dirk EM
Published: May 2003

If lungs could be retrieved for transplantation after circulatory arrest, the shortage of donors might be significantly alleviated. An important issue in using lungs from these so-called non-heart-beating donors is the development of a technique to assess their quality prior to transplantation without jeopardizing the life of the recipient.

In our laboratory we tested the reliability of an ex vivo model for such an evaluation. We used pig lungs from optimal control animals, in casu heart-beating donors. This model enabled us to preserve and evaluate lungs with perfect function up to 24 hours after death. The intermediate assessment is performed in an isolated circuit where the lungs are being ventilated and reper-fused via the pulmonary artery (PA) with autologous and haemodiluted blood. Haemodynamic, aerodynamic and oxygenation parameters are measured at 37.5°C and a maximum PA pressure of 20 mmHg. These data were correlated with premortem values.

During this ex vivo evaluation, leukocyte depletion plays an important role since neutrophils have been recognized as critical components in the inflammatory cascade, which is responsible for graft dysfunction soon and long after transplantation.
Neurological and neuropsychological examination and outcome after use of an intra-aortic filter device during cardiac surgery
Authors: Eifert S , Reichenspurner H , Pfefferkorn T , Baur B , von Schlippenbach C , Mayer T E , Hamann G , Reichart B
Published: May 2003

Cerebral embolization of particles after cardiac surgery is frequently associated with neurological deficits. Aortic crossclamp manipulation seems to be the most significant cause of emboli release during cardiac surgery. The goal of this study was to demonstrate whether the use of an intra-aortic filter device has an effect on the magnet resonance imaging (MRI) and functional neurological outcome.

Twenty-four patients undergoing cardiosurgical procedures using cardiopulmonary bypass (CPB) were selected: coronary artery bypass graft (CABG) surgery (n=17), aortic valve replacement (AVR) surgery (n= 4) or combined procedures (n=3). Patients were evaluated by diffusion weighted MRI of the brain, neurological examination and neuropsychological assessment regarding alertness as well as divided and selective attention before and five to seven days after surgery. The patients were divided into two groups. In group I, 12 patients received a filter through a modified 24 F arterial cannula immediately before the aortic crossclamp was released. Filters remained in the aorta until CPB was discontinued. Intraoperatively, bilateral middle cerebral artery transcranial Doppler (TCD) was monitored at baseline, at the beginning of CPB, at a timepoint when the aorta was crossclamped, when the filter was inserted and while the crossclamp was switched to partial clamping until the CPB was discontinued. TCD was used for detection of microembolic signals (MES). The captured material in the filter was examined histologically. Twelve patients served as controls without aortic filtration (group II).

The MRI of the brain did not show any diffusion alterations in either group before or after surgery. No patient developed a focal neurological deficit or stroke. Intraoperative quantitative MES detection revealed a four to tenfold increase in patients of group I compared with group II (5 - 6 versus 0.5 - 1 MES/min) during the filter dwell time. There was no consistent pattern regarding the neurobehavioural sequelae. Filters showed arteriosclerotic debris in 75% of the patients.

The use of the intra-aortic filter device did not show a positive effect on neurological, neuroradiographical and neuropsychological outcomes. The increase of the MES rate in group I patients may be due to microbubbles generated as microcavitations by the filter or the aortic filter cannula. The intra-aortic filter was able to capture atheromatous material in 75% of the patients.
The embolic potential of liquid fat in pericardial suction blood, and its elimination
Authors: Engström Karl Gunnar
Published: May 2003

Diffuse brain damage is a complex problem in cardiac surgery postoperatively. Liquid fat from recycled pericardial suction blood (PSB) is an embolic source. PSB can be discarded, but the recycling can be life saving, and methods have been developed to remove the fat. Blood washing by centrifugation is suggested to be the most effective method. In retained PSB, fat also separates without centrifugation, which is a novel and simple approach. Alternatively, inline fat filtration is easily accomplished but its effectiveness has been questioned. The present study aimed to investigate this phenomenon. Fat was heat extracted from retrieved pericardial fat tissue of coronary artery bypass graft (CABG) patients (n= 6), and was mixed, 1.25%, with postoperative mediastinal-shed blood. The mixture was filtered using a LipiGuard SB at constant flow rate. The filtration was scaled down to 3 mL and performed under temperature control, 37°C, 20°C and 10°C. At these temperatures fat removal was 46.9±6.1%, 61.5±7.0% and 76.8±5.0%, respectively, with a statistical difference of P=0.001. The improved fat removal at low temperature dramatically increased filtration pressures (p<0.001) and caused haemolysis (P=0.018). It is concluded that fat filtration is technically difficult. Cooling of blood increases fat extraction, but with negative side effects due to filter occlusion.
Blood cardioplegia filtration
Authors: Martin Juergen , Krause Matthias , Benk Christoph , Lutter Georg , Siegenthaler Michael , Beyersdorf Friedhelm
Published: May 2003

The introduction of blood cardioplegia has been proven to limit ischaemia and reperfusion injury in cardiac surgery. But the presence of activated neutrophils in the capillary bed may cause further damage. Leukocyte filters have been shown to be very effective in reducing the leukocytes in blood cardioplegia to less than 10%. Leukocyte depletion of blood cardioplegia provides an excellent approach to minimizing myocardial injury, predominantly in high-risk cardiac surgery.
Prebypass filtration of cardiopulmonary bypass circuits: an outdated technique?
Authors: Merkle Frank , Böttcher Wolfgang , Hetzer Roland
Published: May 2003

Filtration of cardiopulmonary bypass (CPB) priming fluid before connection of the circuit to the patient was first accomplished by arterial line filtration. When dedicated prebypass filters (PBFs) with smaller pore sizes became available, a large number of particles could be found on the filter surface. In recent years, modern manufacturing methods for CPB circuit components were believed to be associated with a reduced number of particles found in components of extracorporeal circuits, making separate filtration of CPB priming solution unnecessary.

Microemboli generated during the preparation and priming procedure of the CPB circuit may consist of either solid particles or gaseous emboli and may contribute to patient morbidity. Endotoxins found in infusion solutions and CPB priming solutions may trigger inflammatory responses when administered into the circulatory system.

Filtration of crystalloid CPB priming solutions with a PBF consisting of a filter membrane with a pore size of0.2 mm was found to effectively reduce the number of microemboli. Infusion filters with a filter pore size of 0.2 mm were found to reduce the endotoxin contamination in infusion solutions. Prebypass filtration with filters containing pores of 0.2 mm should be a necessity for contemporary perfusion practice.
Modification of polymer surfaces: optimization of approaches
Authors: Courtney J M , Zhao X B , Qian H , Sharma A
Published: May 2003

Modification of polymer surfaces to achieve a surface with enhanced compatibility is an important means of obtaining improved biomaterials. Techniques are available for altering the hydrophilicity or charge of a surface, attaching macromolecules or attempting to resemble cell membranes. Relevant to the clinical success of a modified surface is the modification procedure and a procedure based on incorporation as opposed to surface treatment has potential advantages. The modification of plasticized vinyl chloride (PVC) by the incorporation of cyclodextrins is described. In comparison to unmodified PVC controls, cyclodextrin incorporation reduced fibrinogen adsorption, with the extent of reduction dependent on the type and quantity of cyclodextrin incorporated.
Parenteral antibiotics in a palliative care unit: prospective analysis of current practice
Authors: Clayton Josephine , Fardell Belinda , Hutton-Potts Jane , Webb David , Chye Richard
Published: May 2003

All patients receiving parenteral antibiotics in a palliative care unit were prospectively monitored over a 13-month period. Of 913 consecutive admissions, 41 patients received 43 courses of parenteral antibiotics. On 27 of 43 occasions, the use of parenteral antibiotics was considered helpful (62%), in eight cases it was considered unhelpful (19%) and in a further eight cases the outcome could not be assessed (19%). The sites of infection for which parenteral antibiotics were prescribed included urinary tract infections (37%), lower respiratory tract infections (26%), soft tissue/skin or wound infections (16%), purulent terminal respiratory secretions (5%) and other (16%). In this sample, urinary tract infections were more commonly associated with a positive outcome than other indications combined (88% versus 48%, respectively). There appeared to be no association between outcome of use and age of the patient (median age 70, range 37–90), underlying diagnosis (HIV versus advanced malignancy) and reason for admission (symptom control versus respite care versus terminal care). However, outcomes appeared to vary in this sample according to the palliative care phase of the patient at the time parenteral antibiotics were administered. Positive outcomes were more common in terminal- (83%) and stable-phase (71%) patients than deteriorating- (58%) or acute-phase (38%) patients. This survey demonstrates that in specific circumstances a beneficial role exists for the use of parenteral antibiotics in a palliative care setting. The establishment of appropriate guidelines is recommended.
Non-invasive ventilation and palliation: experience in a district general hospital and a review
Authors: Shee Charles D , Green Margaret
Published: May 2003

Non-invasive ventilation (NIV) is increasingly being used in hospitals to treat respiratory failure. The use of NIV with palliative intent in a district general hospital is described and ten illustrative cases where NIV was used in an attempt to palliate symptoms or to ‘buy time’ are presented. The role of NIV in relieving symptoms in various conditions is reviewed and ethical aspects are considered. It is suggested that hospital palliative care teams will increasingly see patients treated by this technique as it becomes more widely used for exacerbations of chronic obstructive airways disease, for relief of breathlessness in the terminally ill and for buying time in patient management. Domiciliary teams will see increasing numbers of people with motor neurone disease and other conditions treated with NIV.
Psychosocial needs in cancer patients related to religious belief
Authors: Mclllmurray M B , Francis B , Harman J C , Morris S M , Soothill K , Thomas C
Published: May 2003

In a study of psychosocial needs amongst cancer patients, the possession of a religious faith has been identified as a significant factor in determining a range of psychosocial needs. Of the 354 respondents to a questionnaire, which included a comprehensive psychosocial needs inventory, 83% said they had a religious faith, and in general these patients were less reliant on health professionals, had less need for information, attached less importance to the maintenance of independence and had less need for help with feelings of guilt, with their sexuality or with some practical matters than those who said they had no religious faith. In addition, they had fewer unmet needs overall (32% compared with 52%). The knowledge of a patient's spirituality should help service providers to predict aspects of psychosocial need and to respond sensitively and appropriately to a patient's experience of cancer.
Quality of life in palliative care: principles and practice
Authors: Kaasa Stein , Loge Jon Håvard
Published: May 2003

In healthcare, most researchers and clinicians agree that quality of life (QOL) is related to symptoms, functioning, psychological and social wellbeing, and probably to a lesser extent to meaning and fulfilment. This multidimensional health-oriented concept has been named health-related quality of life (HRQOL). However, during end-of-life care spirituality and existential issues become more prominent, as well as family members’ perception of quality of care. Outcome measures in palliative care require constructs that reflect the specific goals of palliative care, such as improving QOL before death, symptom control, family support and satisfaction, as well as patients’ perceptions of ‘purpose’ and ‘meaning of life’. It is generally recommended that internationally developed and validated patient-rated multidimensional questionnaires should be used when assessing HRQOL in research. However, ‘multidimensionality’, with often more than 10 possible outcomes, is a threat both to statistical analysis and clinical interpretation of data. Preferentially, a more limited number of outcomes based upon the research question(s) should be defined prior to data collection in the study protocol. The researcher needs to carefully evaluate the content of the questionnaire, in addition to other properties, such as the validity and reliability, before the final decision is made with regards to which instrument to use in a given study.
Caring for the dying: how well prepared are general practitioners? A questionnaire study in Wales
Authors: Barclay Stephen , Wyatt Penny , Shore Sarah , Finlay Ilora , Grande Gunn , Todd Chris
Published: May 2003

Context: General practitioners (GPs) and generalist hospital doctors provide the majority of palliative and terminal care in the UK. Studies have revealed problems with symptom control and communication in these settings and inadequate training for clinical students and junior doctors. Objectives: To investigate the training of GPs in Wales in palliative medicine throughout their careers, with a focus on the Welsh Valleys, an area of social deprivation and high levels of chronic ill health. To compare these data with those previously obtained from a survey of GPs in East Anglia. To develop regression models that enable the prediction of less well trained medical students and GPs. Methods: A postal questionnaire survey of a random sample of GPs, stratified by practice location (Valleys or elsewhere in Wales). Responders were invited to recall their training in five topics of palliative care (pain control, other symptom control, use of syringe drivers, communication skills and bereavement care) during four career stages (clinical students, junior doctors, GP registrars and GP principals). Results: The response rate was 67.6%. Available data enabled evaluation of generalizability and response bias. Contrary to an initial hypothesis, no significant differences were found between Valleys and non-Valleys responders' reported training, although the study was adequately powered. As medical students, 27% reported receiving no training in any topic, 75% no training in bereavement care and 50% no training in communication skills. Training varied across medical schools and was more common for more recent graduates. As junior doctors, 25% reported no training in any topic, 75% no training in bereavement care and 77% no training in communication skills. The GP registrar year provided significantly more coverage of communication, bereavement and syringe drivers than the combined preceding 6 years of general professional training. As GP principals, a high level of training is reported in all topics. The training experience of GPs in Wales is very similar to that previously reported by GPs in East Anglia: this lends support to the generalizability of these data. Logistic regression analysis indicated that the only predictor of less common training as medical students was having qualified less recently. The main predictors of less common training as GP principals was having become a GP more recently and not being a GP trainer. Conclusions: There is still some way to go in ensuring that medical students, junior hospital doctors and GPs are all adequately trained for their important role in caring for dying patients.
What is the best way to help caregivers in cancer and palliative care? A systematic literature review of interventions and their effectiveness
Authors: Harding R , Higginson I J
Published: May 2003

Informal carers in cancer and palliative care are known to have high needs and psychological morbidity, yet a literature review identified few targeted interventions. This systematic review of interventions for carers of patients using home cancer and palliative care services searched Medline, CancerLit, PsycInfo and Cinahl databases. The terms used were carer(s), caregiver(s), palliative and cancer. Papers that reported interventions for adults actively providing informal care for noninstitutionalized cancer and palliative care patients were reviewed. Twenty-two interventions were identified, comprising home nursing care (four), respite services (three), social networks and activity enhancement (two), problem solving and education (three) and group work (10). Of these, nine were delivered solely to carers (i.e., were targeted services). Only six of the carers' interventions had been evaluated, two of these had used a randomized control trial (RCT; grades IB), three employed a single group methodology (two prospective grades IIIC and one retrospective grade IIIC) and one was evaluated using facilitator feedback.

There was a lack of outcome evaluation designs, small sample sizes and a reliance on intervention descriptions and formative evaluations. Methodological challenges may mean alternatives to ‘pure’ RCTs should be considered. The current evidence contributes more to understanding feasibility and acceptability than to effectiveness. Practitioners and evaluators must prioritize the further development of intervention studies.
The palliative care needs of people with intellectual disabilities: a literature review
Authors: Tuffrey-Wijne Irene
Published: May 2003

People with intellectual disabilities are among the most disadvantaged groups in society. A literature review was conducted aiming to answer the following question: What are the palliative care needs of people with intellectual disabilities? The literature review covers case histories, morbidity and mortality patterns for people with intellectual disabilities, their healthcare needs and primary care provision, the way they may present symptoms, their conceptualization of illness and death and issues around education and training. While the literature review reveals a lack of empirical data around the palliative care needs of people with intellectual disabilities, a number of potential problem areas are highlighted. These include late presentation of illness, difficulties in assessing symptoms, difficulties in understanding the illness and its implications and ethical issues around decision making and consent to treatment. It is suggested that future studies will need to include the views and experiences of people with intellectual disabilities themselves. Areas for possible future development include symptom assessment, evaluation of current practice and access to services and the development of information and training materials.
Liechtenstein and Gribeauval: ‘Artillery Revolution’ in Political and Cultural Context
Authors: MacLennan Ken
Published: May 2003

This article compares artillery and ordnance reform in 1750s Austria and 1760s France. Although the reform programmes were very similar technologically, they assumed considerably different significance in the context of their respective militaries and societies. In France, Gribeauval’s system became part of the larger intellectual project of recasting French government and society in a technocratic mould, a project that persisted (against opposition) into the Revolutionary and Napoleonic periods. In Austria, the different structure and organizational culture of the ‘technical arms’, a military culture with different assumptions about knowledge and expertise, and a more narrowly based political culture made the Liechtenstein reforms part of a considerably less radical centralizing policy.
The Mechanization of the British Cavalry between the World Wars
Authors: French David
Published: May 2003

This article takes issue with the argument that the mechanization of the British cavalry was retarded because of the cavalry’s irrational attachment to their horses, and that the Royal Tank Corps were the champions of ‘progress’ in the face of the obscurantism of the cavalry. In the 1920s, because of the mechanical shortcomings of armoured fighting vehicles (AFVs), there were still some tasks that horsed cavalry could perform better than tanks or armoured cars. The decision to mechanize the regular cavalry was delayed until the mid-1930s not merely because of a shortage of the funds to purchase sufficient AFVs. It was delayed because it was not until then that even half-satisfactory vehicles were ready.
Ludendorff and Hitler in Perspective: The Battle for the German Soldier’s Mind, 1917-1944
Authors: Förster Jürgen
Published: May 2003

This article compares German attempts at the end of the two world wars at producing soldiers who knew how to fight and what to fight for, and who had a confident home front that backed them. Both the political and military leadership in charge in 1917/18 and 1944/45 used strong patriotic language to transfer a victory-winning spirit into the troops and the country. In comparison, it becomes clear that both efforts to uplift morale, even invigorate enthusiasm, were integral elements of the overall conduct of war. The official racism and enemy image of Jewish Bolshevism, however, separates Hitler’s ideological indoctrination from Ludendorff’s patriotic instruction.
Flames over the Somme: A Retort to William Philpott
Authors: Greenhalgh Elizabeth
Published: May 2003

This response to William Philpott’s ‘Why the British Were Really on the Somme’ ( War in Historyxi, 4) underlines Philpott’s failure to take adequate account of French sources, dismisses his long defence of Kitchener as beside the point and views his ‘strategic paradox’ as no more convincing for its reiteration. His ‘seven types of success’, offered as an alternative to my judgement that the 1916 battle of the Somme was a failure, are demonstrated to be fragile, nugatory and unsubstantiated. The theme of the response is that an examination and knowledge of French archival and published sources are crucial to any balanced understanding of the Somme battle.
Katalytische Ammoniaksynthese – eine “unendliche Geschichte”?
Authors: Schlögl Robert
Published: May 2003

Stickstoffatome sind funktional notwendig in biologischen Molekülen und finden sich daher auch in Düngemitteln und Pharmaka. Nichtbiologische Nutzanwendungen von Bindungen zu Stickstoffatomen sind Farbstoffe, Sprengmittel und Hartstoffe. Alle Synthesen dieser Materialien verwenden das Schlüsselmolekül Ammoniak als aktivierten Stickstoffbaustein. Dies gilt für natürliche Prozesse ebenso wie für die chemische Technik. Das Wissen um die vielfältigen Verfahren zur Herstellung von Ammoniak ist daher von zentraler Bedeutung für die Chemie. Die Haber‐Bosch‐Synthese ist das erste und noch heute eingesetzte Verfahren der industriellen heterogenen Katalysetechnik. Die Aufklärung des Wirkmechanismus und die Umsetzung zur technischen Perfektion wurden zum Prüfstein für die wissenschaftliche Grundlagenentwicklung der Katalyseforschung.
Dark reactions of free radicals trapped in densely crosslinked polymer networks after photopolymerization
Authors: Pavlinec Juraj , Moszner Norbert
Published: May 2003

Difunctional methacrylate monomers containing stiff or flexible spacers were combined with a vinylcyclopropane derivate in a copolymerization to form densely crosslinked networks. The high rate of visible light photoinitiation at 20–22°C was used for starting the polymerization. By switching off the light after 40 s, the long‐lived free radicals, trapped in the polymer network, retain radical processes, however, at substantially retarded rates. The postcuring development of the network structure in the investigated samples lasting at least 12 weeks was proved by the increasing density of the crosslinks, by the increasing amount of the gel fraction, and by the decreasing of the residual unsaturation. The relaxation spectra from dynamic mechanical thermal analyses (DMTA) show curves with two evident maxima. The first one belonged the glass transition (Tg) of original network and increases in the postcuring period. The second one belonged to the final structure to which the crosslinked polymer approaches slowly during aging. The final state develops fast during a DMTA thermal scan to 200°C. All procedures proceeded in the dark, but in the presence of air oxygen. The chemiluminescence (CL) response of the postcured samples proved the accumulation of hydroperoxides. The oxidation chain reaction took place in the postcuring time and competed with the building up of additional crosslinks. The majority of postcuring changes were observed during the first 3 weeks of aging. Nine weeks later, the long‐lived radicals were still present in the network and maintained the sensibility of the crosslinked polymer to free‐radical reactions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 579–588, 2003
Butadiene polymerization in the presence of VOCl3–dialkylmagnesium catalytic system
Authors: Monakov Yu. B. , Mullagaliev I. R. , Kharitonova E. Yu.
Published: May 2003

The butadiene polymerization in toluene at 25°C on VOCl3(n‐C4H9)Mg(iso‐C8H17) catalytic system was investigated. The kinetic parameters of polymerization and molecular characteristics of polybutadiene were determined. It was shown that substitution of traditional organoaluminum cocatalysts in trans‐regulating vanadium systems does not have an effect on its stereospecificity, but significantly influences on the active centers reaction ability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 596–600, 2003
Structure of active centers, their stereospecificity distribution, and multiplicity in diene polymerization initiated by NdCl3‐based catalytic systems
Authors: Urazbaev V. N. , Efimov V. P. , Sabirov Z. M. , Monakov Yu. B.
Published: May 2003

On the basis of quantum‐chemical calculations, it was shown that among six types of active centers (ACs) that can form during the polymerization of butadiene with lanthanide‐based catalytic systems, five types (containing electron‐accepting chlorine atoms in the coordination sphere of a lanthanide) exhibit a π‐allyl binding of the terminal unit of a growing polymer chain to a lanthanide atom and function as cis‐regulating. The sixth type of ACs is characterized by a σ‐alkyl structure and shows a trans‐stereospecificity. This results was used to interpret the data on the microstructure of polybutadiene prepared using NdCl3 · 3TBP‐Al(iso‐C4H9)3, NdCl3 · 3TBP–Mg(n‐C4H9)(iso‐C8H17) catalytic systems and their combinations (TBP is tributyl phosphate). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 601–603, 2003
Fiber spinning from poly(propylene)–organoclay nanocomposite
Authors: Pavliková Silvia , Thomann Ralf , Reichert Peter , Mülhaupt Rolf , Marcinčin Anton , Borsig Eberhard
Published: May 2003

SOMASIF ME C16, a filler that enables generation of anisotropic nanoparticles by in situ exfoliation of organic layered silicates, was melt compounded with poly(propylene) (PP) in the presence of maleic anhydride‐grafted PP. Fibers were prepared from this composite by a spinning procedure. The prepared anisotropic fibers were partially oriented by using different drawing ratios. The morphological study showed that the drawing ratio of the fibers particularly influences the level of exfoliation of the SOMASIF ME C16 where the nanoparticles are formed. The layered sheets of the SOMASIF particles are oriented in the direction of the fiber axis. The tensile strength of the filled fibers increases with the increase of drawing ratio much more than that of unfilled PP fibers. This result is accounted for by the formation of exfoliated structures from the nanoparticles of SOMASIF ME C16 by fiber drawing. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 604–611, 2003
Isothermal and nonisothermal transition kinetics of trans‐1,4‐polybutadiene
Authors: Cai Jiali , Bo Shuqin , Li Gao , Zhou Enle , Cheng Rongshi
Published: May 2003

Analysis of the isothermal and nonisothermal transitions of hexagonal crystal formation from the melt (transition 1) and of monoclinic crystal formation from hexagonal crystals (transition 2) for trans‐1,4‐polybutadiene (TPBD) was carefully carried out by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). Isothermal transitions 1 and 2 are described by Avrami exponents (n) of ≈1, whereas nonisothermal transitions 1 and 2 are described by n ≈ 4. These different n values indicate that different crystallization mechanisms took place for different crystallization driving forces under isothermal and nonisothermal crystallization. The Ozawa equation was also used to analyze the nonisothermal crystallization data. For transition 1 at lower temperature, the Ozawa equation fits the data well; however, at higher temperature, there is an inflection that shifts to lower crystallinity with increasing temperature. Inflections are also observed with the Ozawa analysis for transition 2. Furthermore, the crystallinities at the turning points are almost in the same range as those determined by Avrami analysis for nonisothermal transitions 1 and 2, which suggests that the Ozawa analysis inflections are due to secondary crystallization. However, TEM revealed no morphology discrepancy between the TPBD hexagonal crystals formed from melt by isothermal and nonisothermal crystallization. The agreement in activation energy (ΔE) values determined by the Arrhenius and Kissinger methods indicates that the Avrami equation can describe the initial stage of transitions 1 and 2 in the nonisothermal transition process quite well. The ΔE values determined by the Arrhenius and Kissinger methods for transition 1 are 167.4 and 179.2 KJ/mol, respectively, and those for transition 2 are 186.1 and 196.3 KJ/mol; respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 612–619, 2003
Use of zinc‐neutralized ethylene/methacrylic acid copolymer ionomers as blend compatibilizers for nylon 6 and low‐density polyethylene
Authors: Leewajanakul Panita , Pattanaolarn Rungravee , Ellis John W. , Nithitanakul Manit , Grady Brian P.
Published: May 2003

The effect of the composition on the morphologies and properties of uncompatibilized and compatibilized blends of nylon 6 and low‐density polyethylene were studied over a wide range of weight fractions. The uncompatibilized blends had substantially reduced mechanical properties after mixing, and this was almost certainly due to poor interfacial adhesion between the two polymers. The addition of a zinc‐neutralized poly(ethylene‐co‐methacrylic acid) ionomer (Surlyn® 9020) as a compatibilizer improved the mechanical properties in comparison with those of the material blended without the compatibilizer. The clearest evidence of this improvement came from dynamic mechanical studies; for selected blends with high polyethylene contents, the drop in the modulus corresponding to the transition of a solid to a melt occurred at higher temperatures with the added compatibilizer. This improvement in the properties was accompanied by a reduction in the dispersed‐phase size due to the interaction between the ionic part of the ionomer and the amide groups of nylon 6, especially when nylon 6 was the dispersed phase of the blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 620–629, 2003
Homogeneous graft copolymerization of acrylonitrile onto high α‐cellulose in a dimethyl acetamide and lithium chloride solvent system
Authors: Das Pradeep , Saikia C. N.
Published: May 2003

Homogeneous graft copolymerization of acrylonitrile (AN) monomer onto high α‐cellulose was investigated in a lithium chloride/N,N‐dimethyl acetamide (DMAc/LiCl) solvent system. Benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) were used as radical initiators. By varying temperature, time, and monomer concentrations in grafting reactions, the optimum conditions for both initiator systems were fixed. The graft yield for the AN–BPO system was higher than that for the AN–AIBN system. The optimum conditions of reactions were at temperatures of 70 and 60°C with initiator concentrations of 0.4% (0.36 mmol) and 2% (1.24 mmol) for the AN–AIBN and AN–BPO systems, respectively, at a monomer concentration of 5% (14.1 mmol) solution. The number of grafts per cellulose chain was in the range from 2.2 to 1.1 for AN–BPO and 0.5 to 2.1 for the AN–AIBN system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 630–637, 2003
Graft modification of highly chlorinated polyethylene (HCPE) with methyl methacrylate by the mechanochemistry reaction. I. Synthesis and characterization
Authors: Zhao Ji‐Ruo , Feng Ying , Chen Xin‐Feng
Published: May 2003

Highly chlorinated polyethylene‐graft‐methyl methacrylate (HCPE‐g‐MMA; HCPE with chlorine contents > 60%), obtained by a mechanochemistry reaction, is discussed in detail. A two‐roll mill was used in the process. The reaction conditions affecting the structure of HCPE‐g‐MMA copolymers were measured in terms of calculation of graft efficiency (GE), graft degree (GD), and copolymerization rate/homopolymerization rate (Rc/Rh) by 1H‐NMR spectroscopy. Based on these results, it is concluded that the chlorine contents of HCPE, the additional amount of MMA, and the mechanochemistry reaction time all have impacts on the structure of the polymer. The results also confirm that grafting is very much favored by the mechanochemistry reaction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 811–816, 2003
Synthesis, characterization, and antimicrobial activity of acrylic copolymers
Authors: Patel Mitesh B. , Patel Samir A. , Ray Arabinda , Patel Rajni M.
Published: May 2003

2,4‐Dichlorophenyl methacrylate (2,4‐DMA) and vinyl acetate (VAc) were copolymerized with different feed ratios using dimethyl formamide (DMF) as a solvent and 2,2′‐azobisisobutyronitrile (AIBN) as an initiator at 70°C. The copolymers were characterized by infrared (IR) spectroscopy. Copolymer compositions were determined by ultraviolet (UV) spectroscopy. The monomer reactivity ratios were evaluated by the Fineman–Ross method. Average molecular weight and polydispersity index were determined by gel permeation chromatography (GPC), and the intrinsic viscosities of polymers were also discussed. Thermogravimetric analyses of polymers were carried out under a nitrogen atmosphere. The homo‐ and copolymers were tested for their antimicrobial activity against selected microorganisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 895–900, 2003
Study on the mechanical and dielectric properties of photocured jute fabrics with 2‐hydroxyethyl methacrylate
Authors: Khan Mubarak A. , Das L. R. , Khan A. H. , Ahmed F. , Badier Rahman S. M.
Published: May 2003

Jute fabric (Hessian cloth) was treated with 2‐hydroxyethyl methacrylate (HEMA) under ultraviolet radiation in order to improve the mechanical and electrical properties. Concentration of the monomer 2‐hydroxyethyl methacrylate (HEMA), radiation dose, and soaking time were optimized with respect to mechanical properties such as tensile strength and elongation at break of the treated and untreated Hessian cloth. The 10% HEMA, 15 min soaking time, and 15th pass of radiation rendered the best tensile properties. The variations of dielectric properties with temperature were measured at 10 kHz frequency. It was observed that dielectric constant and loss tangent (tan Ω) increased with increasing temperature up to the transition temperature and then decreased, and at the end become almost constant. The surfaces of treated and untreated jute were characterized by scanning electron microscope. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 655–661, 2003
Preparation of photoluminescence films containing rare earth complexes by UV photograft polymerization
Authors: Li Jian‐Yu , Sun Yu‐Mei , Zeng Hong , Xue Wei‐Xing , Xiao Yang , Yu Qun
Published: May 2003

To avoid the fluorescence quenching resulting from the uneven dispersion of fluorescent rare earth complexes in photoluminescence films, which were prepared by blending until recently, photoluminescence films were prepared in which the chemical bond combination occurs between the fluorescent rare earth complexes and the macromolecular material. Acrylic acid (AA) was grafted onto polyethylene (PE) film through liquid‐phase UV photograft polymerization. Then the grafted films (PAA‐g‐PE) were reacted with a solution of Eu3+and thenoyltrifluoroacetone (TTA) in alcohol–water and with a solution of Tb3+and acetylacetone (AcAc) in chloroform–water, respectively. Thus, red (Eu3+–TTA–PAA‐g‐PE) and green (Tb3+–ACAC–PAA‐g‐PE) photoluminescence films were obtained. The fluorescence and infrared spectra of the photoluminescence films were recorded. Compared with their corresponding solid fluorescent complexes, both the excitation and emission wavelengths of the photoluminescence films prepared in this way had been changed remarkably, indicating that the fluorescent rare earth complexes had been chemically bonded onto the PE film. Moreover, the effects of the conditions (including pH value, reaction time, and temperature) of the reaction of the grafted film with the solution containing Eu3+and TTA on the fluorescence intensity of the red photoluminescence film were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 662–667, 2003
Preparation, characterization, and properties of cellulose–polyacrylamide graft copolymers
Authors: Okieimen F. E.
Published: May 2003

Graft copolymers of acrylamide on cellulose materials (α‐cellulose 55.8%, DP 287.3) obtained from Terminalia superba wood meal and its carboxymethylated derivative (DS 0.438) were prepared using a ceric ion initiator and batch polymerization and modified batch polymerization processes. The extent of graft polymer formation was measured in graft level, grafting efficiency, molecular weight of grafted polymer chains, frequency of grafting as a function of the polymerization medium, and initiator and monomer concentrations. It was found that the modified batch polymerization process yielded greater graft polymer formation and that graft copolymerization in aqueous alcohol medium resulted in enhanced levels of grafting and formation of many short grafted polymer chains. Viscosity measurements in aqueous solutions of carboxymethyl cellulose‐g‐polyacrylamide copolymer samples showed that interpositioning of polyacrylamide chains markedly increased the specific viscosity and resistance to biodegradation of the graft copolymers. The flocculation characteristics of the graft copolymers were determined with kaolin suspension. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 913–923, 2003
Synthesis and characterization of macrocyclic polyamine derivative of chitosan
Authors: Yang Zhikuan , Cheng Shuyu
Published: May 2003

A novel macrocyclic polyamine derivative of chitosan was synthesized by a reaction between chitosan and epoxy‐activated macrocyclic polyamine. The copolymer that is obtained contains amino functional groups in its skeleton and secondary amine and more polar hydroxyl groups. Four types of analyses were used to characterize the chemical modifications of the chitosan: elemental, FTIR spectra, solid‐state 13C‐NMR, and X‐ray diffraction. The adsorption properties of the macrocyclic polyamine grafted chitosan for Ag+, Cu2+, Co2+, and Cr3+ were also investigated. The experimental results showed that the new macrocyclic polyamine derivative of chitosan has high adsorption capacity and good selectivity for Ag+ in the presence of Ag+, Co2+, and Cr3+. The selectivity coefficients were K = 6.16, K = 14.81, and K = 2.42, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 924–929, 2003
The nature of the organoaluminum compound and the kinetic heterogeneity of active sites in lanthanide‐based diene polymerization
Authors: Sigaeva N. N. , Usmanov T. S. , Zaikov G. E. , Monakov Yu. B.
Published: May 2003

The influence of the organoaluminum compound on the kinetic heterogeneity of active sites in lanthanide‐based diene polymerization was investigated. It was found that the heterogeneity of investigated catalytic systems was shown in the existence of four types of active centers. They were formed at the beginning of the polymerization process and produced macromolecules with lengths that were definite for each type of active center. The nature of the organoaluminum compound greatly influenced the kinetic activity of the polymerization centers. A method for analyzing the curves' maximums of distribution on kinetic activity and the change in kinetic activity of every type of active centers is proposed. This method allows calculating the concentration values for each type of active center separately. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 674–685, 2003
Studies on epoxidized rubber seed oil as plasticizer for acrylonitrile butadiene rubber
Authors: Joseph Reethamma , Alex Rosamma , Vinod V. S. , Premalatha C. K. , Kuriakose Baby
Published: May 2003

The application of rubber seed oil (RSO) and epoxidized RSO (ERSO) as a plasticizer in acrylonitrile butadiene rubber (NBR) was studied using RSO and ERSO with different levels of epoxidation. The results indicated that ERSO could be used as a less leachable and low volatility plasticizer for NBR. The use of ERSO in NBR gave better abrasion resistance whereas the tensile strength and tear strength were comparable to those vulcanizates that contained dioctyl phthalate as a plasticizer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 668–673, 2003
Study of polyaniline polyacrylamide composites by positron annihilation technique
Authors: Das B. , Kar Sumit , Sanyal D. , Banerjee D. , Bhattacharya R.
Published: May 2003

Polyaniline doped with nonoxidizing Bronsted acids is recognized as a conducting material, as its electrical conductivity changes with percentage of doping. In the present work, different percentages of doped polyaniline were blended with polyacrylamide and their electrical conductivities as well as the positron annihilation lifetimes were measured. Analysis of data yielded three lifetime components. It was observed that the value of the short lifetime component remained constant for doping concentration, whereas that of the intermediate component τ2 decreased. The relative intensity pertaining to τ2, however, increased with the increase in doped PANI concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 930–933, 2003