bluuebunny/crossref_metadata_2025 huggingface dataset:
The Outcome of Combined-Modality Therapy for Stage III Non–Small-Cell Lung Cancer in the Elderly
Authors: Schild Steven E. , Stella Philip J. , Geyer Susan M. , Bonner James A. , McGinnis William L. , Mailliard James A. , Brindle Jeffery , Jatoi Aminah , Jett James R.
Published: July 2003

Purpose: The North Central Cancer Treatment Group performed a phase III trial to determine whether chemotherapy plus either bid radiation therapy (RT) or daily (qd) RT resulted in a better outcome for patients with stage III non–small-cell lung cancer (NSCLC). No difference in survival was identified between the two arms. This secondary analysis was performed to examine the relationship between patient age and outcome.

Patients and Methods: Two hundred forty-six patients were randomized to receive etoposide plus cisplatin and either RT qd or split-course RT bid. This retrospective study compared the outcomes of patients aged ≥70 years (“elderly patients”) with those of younger individuals. Of the 244 assessable patients, 63 (26%) were elderly, and 181 (74%) were younger individuals.

Results: The 2-year and 5-year survival rates were 39% and 18%, respectively, in patients younger than 70 years, compared with 36% and 13%, respectively, in elderly patients (P = .4). Grade 4+ toxicity occurred in 62% of patients younger than 70 years compared with 81% of elderly patients (P = .007). Grade 4+ hematologic toxicity occurred in 56% of patients younger than 70 years, compared with 78% of elderly patients (P = .003). Grade 4+ pneumonitis occurred in 1% of those younger than 70 years, compared with 6% of elderly patients (P = .02).

Conclusion: Toxicity, especially myelosuppression and pneumonitis, was more pronounced in the elderly patients receiving combined-modality therapy for locally advanced NSCLC. Despite increased toxicity, elderly patients have survival rates equivalent to younger individuals. Therefore, fit, elderly patients with locally advanced NSCLC should be encouraged to receive combined-modality therapy, preferably on clinical trials with cautious, judicious monitoring. Future studies should explore ways to decrease toxicity of therapy in elderly patients.
Neurosteroids Alter γ-Aminobutyric Acid Postsynaptic Currents in Gonadotropin-Releasing Hormone Neurons: A Possible Mechanism for Direct Steroidal Control
Authors: Sullivan Shannon D. , Moenter Suzanne M.
Published: July 2003

Pulsatile GnRH release is required for fertility and is regulated by steroid feedback. Whether or not steroids or their metabolites act directly on GnRH neurons is not well established. In some neurons, steroid metabolites known as neurosteroids modulate the function of the GABAA receptor. Specifically, the progesterone derivative allopregnanolone is an allosteric agonist at this receptor, whereas the androgen dehydroepiandrosterone sulfate (DHEAS) is an allosteric antagonist. We hypothesized these metabolites act similarly on GnRH neurons to modify the response to GABA. Whole-cell voltage-clamp recordings of GABAergic miniature postsynaptic currents (mPSCs) were made from green fluorescent protein-identified GnRH neurons in brain slices from diestrous mice. Glutamatergic currents were blocked with antagonists and action potentials blocked with tetrodotoxin, minimizing presynaptic effects of treatments. Allopregnanolone (5 μm) increased mPSC rate of rise, amplitude and decay time by 15.9 ± 6.1%, 16.5 ± 6.3%, and 58.3 ± 18.6%, respectively (n = 7 cells). DHEAS (5 μm) reduced mPSC rate of rise (32.1 ± 5.7%) and amplitude (27.6 ± 4.3%) but did not alter decay time (n = 8). Effects of both neurosteroids were dose dependent between 0.1 and 10 μm. In addition to independent actions, DHEAS also reversed effects of allopregnanolone on rate of rise and amplitude so that these parameters were returned to pretreatment baseline values (n = 6). These data indicate allopregnanolone increases and DHEAS decreases responsiveness of GnRH neurons to activation of GABAA receptors by differentially modulating current flow through GABAA receptor chloride channels. This provides one mechanism for direct steroid feedback to GnRH neurons.
α6β4 integrin regulates keratinocyte chemotaxis through differential GTPase activation and antagonism of α3β1 integrin
Authors: Russell Alan J. , Fincher Edgar F. , Millman Linda , Smith Robyn , Vela Veronica , Waterman Elizabeth A. , Dey Clara N. , Guide Shireen , Weaver Valerie M. , Marinkovich M. Peter
Published: July 2003

Growth factor-induced cell migration and proliferation are essential for epithelial wound repair. Cell migration during wound repair also depends upon expression of laminin-5, a ligand for α6β4 integrin. We investigated the role of α6β4 integrin in laminin-5-dependent keratinocyte migration by re-expressing normal or attachment-defective β4 integrin in β4 integrin null keratinocytes. We found that expression ofβ4 integrin in either a ligand bound or ligand unbound state was necessary and sufficient for EGF-induced cell migration. In a ligand bound state, β4 integrin supported EGF-induced cell migration though sustained activation of Rac1. In the absence of α6β4 integrin ligation, Rac1 activation became tempered and EGF chemotaxis proceeded through an alternate mechanism that depended upon α3β1 integrin and was characterized by cell scattering. α3β1 integrin also relocalated from cell-cell contacts to sites of basal clustering where it displayed increased conformational activation. The aberrant distribution and activation ofα3β1 integrin in attachment-defective β4 cells could be reversed by the activation of Rac1. Conversely, in WT β4 cells the normal cell-cell localization of α3β1 integrin became aberrant after the inhibition of Rac1. These studies indicate that the extracellular domain ofβ4 integrin, through its ability to bind ligand, functions to integrate the divergent effects of growth factors on the cytoskeleton and adhesion receptors so that coordinated keratinocyte migration can be achieved.
Delineating the position ofrad4+/cut5+ within the DNA-structure checkpoint pathways inSchizosaccharomyces pombe
Authors: Harris Sheila , Kemplen Caroline , Caspari Thomas , Chan Christopher , Lindsay Howard D. , Poitelea Marius , Carr Antony M. , Price Clive
Published: July 2003

The fission yeast BRCT domain protein Rad4/Cut5 is required for genome integrity checkpoint responses and DNA replication. Here we address the position at which Rad4/Cut5 acts within the checkpoint response pathways. Rad4 is shown to act upstream of the effector kinases Chk1 and Cds1, as both Chk1 phosphorylation and Cds1 kinase activity require functional Rad4. Phosphorylation of Rad9, Rad26 and Hus1 in response to either DNA damage or inhibition of DNA replication are independent of Rad4/Cut5 checkpoint function. Further we show that a novel, epitope-tagged allele of rad4+/cut5+ acts as a dominant suppressor of the checkpoint deficiencies of rad3-, rad26- and rad17- mutants. Suppression results in the restoration of mitotic arrest and is dependent upon the remaining checkpoint Rad proteins and the two effector kinases. High-level expression of the rad4+/cut5+ allele in rad17 mutant cells restores the nuclear localization of Rad9, but this does not fully account for the observed suppression. We conclude from these data that Rad4/Cut5 acts with Rad3, Rad26 and Rad17 to effect the checkpoint response, and a model for its function is discussed.
Relationships among CSF monoamine metabolite levels, alcohol sensitivity, and alcohol‐related aggression in rhesus macaques
Authors: Barr Christina S. , Becker Michelle L. , Suomi Stephen J. , Higley J. Dee
Published: July 2003

A relationship between alcohol intake and aggressive behavior has been demonstrated in both associational and laboratory studies. Among the factors that contribute to aggression during intoxication are a history of violence and the level of alcohol‐induced stimulation. In humans, excessive alcohol intake and alcoholism are predicted by decreased sensitivity, or a low level of response (LOR), to alcohol. In addition, aggressive behavior, LOR, and alcoholism have been attributed to CNS serotonergic dysfunction. Given that they are both related to diminished CNS serotonin, in this study we wanted to determine whether a low LOR to alcohol would be associated with aggression during intoxication in rhesus macaques. Adolescent rhesus macaques (N=115) received an intravenous dose of ethanol (2.2g/kg) and were scored for their levels of response for 30 minutes. Following provocation by an investigator, animals were then scored for aggressive behaviors (lunges, open‐mouth threats, stares, head‐bobs, and barks) for five minutes. At the approximate age of five years, animals were entered into a free‐access alcohol consumption study, during which they were allowed voluntary access for one hour/day, four days/week to aspartame‐sweetened alcohol or vehicle. Alcohol intake for each subject was determined using a computerized collar, which was detected by a station system that measured individual subject consumption rates. Data were analyzed using regression analyses and t‐tests. Decreased sensitivity to alcohol, alcohol‐induced increases in CSF MHPG, and pre‐alcohol CSF levels of 5–HIAA were associated independently with aggression during intoxication (r= −0.32, P= 0.0006 , r = − 0.29, P=0.01, and r= −0.21, P=0.02, respectively). High rates of alcohol‐related aggression predicted future alcohol consumption (r=0.27, p=0.004), even after controlling for rearing condition and monoamine metabolite concentrations, previously shown in these animals to predict alcohol consumption. By investigating the relationships between LOR, central catecholamine reactivity and function, and alcohol‐induced aggression in alcohol‐naïve nonhuman primates, this report provides evidence that alcohol‐induced stimulation and neurotransmitter‐linked predisposition to impulsive aggression independently contribute to aggression during intoxication. This paper further emphasizes the importance of the nonhuman primate model for studying susceptibility to alcohol‐related aggression and alcoholism, because variables such as prior exposure to alcohol are difficult to control in human subjects. Aggr. Behav. 29:288–301, 2003. © 2003 Wiley‐Liss, Inc.
Perpetrators of alcohol‐involved sexual assaults: How do they differ from other sexual assault perpetrators and nonperpetrators?
Authors: Zawacki Tina , Abbey Antonia , Buck Philip O. , McAuslan Pamela , Clinton‐Sherrod A. Monique
Published: July 2003

Approximately 50% of sexual assaults involve alcohol. Researchers have documented situational characteristics that distinguish between sexual assaults that do and do not involve alcohol, but little attention has been paid to differences between the perpetrators of these two types of assault. In this study, discriminant function analysis was used to distinguish between college men (N=356) who reported perpetrating sexual assault that involved alcohol, sexual assault that did not involve alcohol, or no sexual assault. Predictors of sexual assault perpetration that have been documented in past research differentiated nonperpetrators from both types of perpetrators. Perpetrators of sexual assaults that involved alcohol were in most ways similar to perpetrators of sexual assaults that did not, although they did differ on impulsivity, alcohol consumption in sexual situations, and beliefs about alcohol. These findings suggest mechanisms through which alcohol is involved in sexual assault that are relevant to theory and prevention. Aggr. Behav. 29:366–380, 2003. © 2003 Wiley‐Liss, Inc.
Liquid Crystals for Charge Transport, Luminescence, and Photonics
Authors: O'Neill M. , Kelly S.M.
Published: July 2003

Ordered molecular materials are increasingly used in active electronic and photonic organic devices. In this progress report we discuss whether the self‐assembling properties and supramolecular structures of liquid crystals can be tailored to improve such devices. Recent developments in charge‐transporting and luminescent liquid crystals are discussed in the context of material requirements for organic light‐emitting devices, photovoltaics, and thin film transistors. We identify high carrier mobility, polarized emission, and enhanced output‐coupling as the key advantages of nematic and smectic liquid crystals for electroluminescence. The formation of anisotropic polymer networks gives the added benefits of multilayer capability and photopatternability. The anisotropic transport and high carrier mobilities of columnar liquid crystals make them promising candidates for photovoltaics and transistors. We also outline some of the issues in material design and processing that these applications demand. The photonic properties of chiral liquid crystals and their use as mirror‐less lasers are also discussed.
Carbon Nanotube‐Based Biosensor
Authors: Wohlstadter J.N. , Wilbur J.L. , Sigal G.B. , Biebuyck H.A. , Billadeau M.A. , Dong L. , Fischer A.B. , Gudibande S.R. , Jameison S.H. , Kenten J.H. , Leginus J. , Leland J.K. , Massey R.J. , Wohlstadter S.J.
Published: July 2003

Carbon nanotubes, compounded into plastic to create bulk electrodes, form the basis of a novel sensor for biological assays. The nanotubes function as both a solid phase and working electrode for generation of electrochemiluminescence, the detection method used in this system. The Figure shows a scanning electron microscopy image of a composite used for an immunoassay. The bright spots in the image are 10 nm diameter gold colloids covalently attached to antibodies. The inset shows a region of a composite with no gold colloids.
Enhanced Light Extraction from Organic Light‐Emitting Diodes with 2D SiO2/SiNx Photonic Crystals
Authors: Do Y.R. , Kim Y.C. , Song Y.‐W. , Cho C.‐O , Jeon H. , Lee Y.‐J. , Kim S.‐H. , Lee Y.‐H.
Published: July 2003

The introduction of a 2D photonic crystal layer is demonstrated to be an effective way to solve light trapping problems in organic light emitting diodes (OLEDs). The overall effect of the photonic crystal structure on the performance of the OLED is investigated by means of current–voltage–luminance measurements and lifetime tests. A schematic of the structure of the OLED device is shown in the Figure.
Double‐Network Hydrogels with Extremely High Mechanical Strength
Authors: Gong J.P. , Katsuyama Y. , Kurokawa T. , Osada Y.
Published: July 2003

Very strong hydrogels (with a fracture strength of some tens of MPa), as required for both industrial and biomedical applications, have been generated by inducing a double‐network (DN) structure for various combinations of hydrophilic polymers. The Figure shows a hydrogel before, during, and after application of a fracture stress of 17.2 MPa.
Nanopatterning of Magnetic Disks by Single‐Step Ar+ Ion Projection
Authors: Dietzel A. , Berger R. , Loeschner H. , Platzgummer E. , Stengl G. , Bruenger W.H. , Letzkus F.
Published: July 2003

Large‐area Ar+ projection has been used to generate planar magnetic nanostructures on a 1″‐format hard disk in a single step (see Figure). The recording pattern was transferred to a Co/Pt multilayer without resist processes or any other contact to the delicate media surface. It is conceivable that magnetic nanostructures can be replicated from a single stencil mask on large quantities of disks for future high‐density recording.
Strongly Polarized and Efficient Blue Organic Light‐Emitting Diodes Using Monodisperse Glassy Nematic Oligo(fluorene)s
Authors: Culligan S.W. , Geng Y. , Chen S.H. , Klubek K. , Vaeth K.M. , Tang C.W.
Published: July 2003

Monodisperse oligo(fluorene)s have been successfully employed for the construction of polarized blue organic light‐emitting diodes. Uniaxial alignment is accomplished by spin‐casting oligo(fluorene)s onto a rubbed alignment layer with subsequent thermal annealing. The resultant films yield the best set of performance data ever reported in terms of emission dichroic ratio, luminance yield, and chromaticity (see Figure).
Mortality among chrome leather tannery workers: An update
Authors: Stern Frank B.
Published: July 2003

Background

Employees engaged in the tanning and finishing of leather are potentially exposed to numerous carcinogens.

Methods

A previous mortality study among 9,352 workers from two chrome tanneries has been updated with the addition of 11 years of vital status and work history follow‐up and 1,153 new deaths. Ninety‐two different causes of death were analyzed using a modified life‐table approach. Death rates from both the United States and the states in which the tanneries were located were used as the comparison populations in calculating cause‐specific standardized mortality ratios (SMRs).

Results

The mortality risks from all causes and from all cancers were lower than the expected for the combined cohort. Analyzing the two tanneries separately, no a priori cause of death (i.e., cancer of the lung, pancreas, bladder, kidney, testes, nasal cavity, lymphoma, or soft‐tissue sarcoma) was shown to be significantly elevated. An exception was lung cancer at one tannery when state death rates were used (SMR = 130, P < 0.01). Analyzing by duration of employment, no significant trend in any cause of death at either tannery was revealed.

Conclusions

Some studies have shown elevated risks for various site‐specific causes of cancer; however, sites in excess are not consistent between studies. The differences may have been due to distinct processes used by the tanneries resulting in varying levels, as well as different types, of exposures. Am. J. Ind. Med. 44:197–206, 2003. Published 2003 Wiley‐Liss, Inc.
Estimating the total number of newly‐recognized silicosis cases in the United States
Authors: Rosenman Kenneth D. , Reilly Mary Jo , Henneberger Paul K.
Published: July 2003

Background

The US employer‐based surveillance system for documenting occupational injuries and illnesses undercounts chronic diseases. We suggest a method to estimate the number of individuals who are newly‐recognized with silicosis each year in the United States.

Methods

Data from US death certificates, the Michigan state‐based surveillance system, and capture–recapture analysis were used to calculate national estimates of silicosis.

Results

From 1987 to 1996, 2,787 deaths occurred in the United States where silicosis was mentioned on the death certificates. During the same period, in Michigan 77% of death certificates with a mention of silicosis were confirmed as silicosis‐related deaths and the ratio of the number of living to deceased confirmed silicosis cases was 6.44. The proportion of confirmed silicosis deaths, the ratio of the living to deceased silicosis cases and capture–recapture analysis from the Michigan surveillance system, were used to estimate that there were 3,600–7,300 cases per year of silicosis in the United States from 1987 to 1996.

Conclusions

Our estimate of the annual number of newly‐recognized silicosis cases is significantly larger than the estimate from the employer‐based reporting system used for counting occupational disease in the United States. This employer‐based surveillance system is inadequate for determining the frequency of occupational disease. Our analysis which combines a readily‐available and relatively inexpensive national administrative database (i.e., death certificates) with a more costly state‐based active surveillance system is a cost‐effective model that could be used to provide better estimates of a number of different occupational diseases. Accurate estimates of occupational illnesses are essential to both determine temporal trends and evaluate efforts to prevent silicosis. Am. J. Ind. Med. 44:141–147, 2003. © 2003 Wiley‐Liss, Inc.
Fatal occupational injuries among self‐employed workers in North Carolina
Authors: Mirabelli Maria C. , Loomis Dana , Richardson David B.
Published: July 2003

Background

Research suggests that rates of occupational injury and death may be higher among self‐employed workers than in the wage and salaried population. This analysis was conducted to describe the demographic and occupational characteristics, as well as injuries, activities, and occupations of self‐employed workers who are fatally injured on the job.

Methods

Characteristics of workers by type of employment were compared using data from the North Carolina Office of the Chief Medical Examiner, 1978–1994. Age‐, activity‐, and industry‐specific fatality rates in self‐employed workers (N = 395) were contrasted to those privately employed (N = 1,654).

Results

Highest fatal injury rates among the self‐employed occurred in agriculture, retail, and transportation industries. Homicide deaths occurred more frequently among self‐employed workers; deaths resulting from unintentional injuries occurred more frequently among non‐self‐employed workers.

Conclusions

Elevated occupational fatality death rates among self‐employed workers, especially in retail and transportation industries, provide justification for addressing work‐related conditions of self‐employed workers in North Carolina. Am. J. Ind. Med. 44:182–190, 2003. © 2003 Wiley‐Liss, Inc.
Pneumoconiosis in a vermiculite end‐product user
Authors: Howard Thomas Peter
Published: July 2003

Background

Vermiculite is a silicate used as an insulating agent, soil additive, and carrier for chemicals and fertilizers. It is currently perceived to have no adverse effects to “end‐product” users. An 82‐year‐old man presented with complaints of progressive dyspnea on exertion.

Methods

A clinical evaluation included a chest radiograph, complete pulmonary function testing, CT scan of the thorax, and comprehensive occupational and environmental history.

Results

The patient had clinical and radiographic features of advanced pulmonary interstitial fibrosis. The presence of calcified pleural plaques, together with the other clinical and radiographic features, strongly supported a diagnosis of asbestosis. His only significant exposure was to vermiculite used in the workplace for several hours per day from 1970 to 1987.

Conclusions

This case represents the first report of an end‐product vermiculite‐user with probable asbestosis, and together with recent similar findings in a vermiculite expansion plant worker, requires further epidemiologic investigations. Am. J. Ind. Med. 44:214–217, 2003. Published 2003 Wiley‐Liss, Inc.
Respiratory health of cobalt production workers
Authors: Linna Asko , Oksa Panu , Palmroos Pirjo , Roto Pekka , Laippala Pekka , Uitti Jukka
Published: July 2003

Background

Cobalt production workers are exposed to metallic cobalt and nickel and their compounds and to different irritant gases. The aim of our study was to determine whether long‐term exposure is associated with an increased occurrence of respiratory symptoms and findings or diseases, other than asthma, which is a known hazard, among cobalt processing workers.

Methods

The study population was comprised of 110 current and former cobalt workers who had worked more than 10 years in a cobalt plant. The reference group consisted of 140 unexposed workers. All the participants were men. The analysis was based on exposure history, pulmonary function, chest X‐ray findings, and symptom questionnaires.

Results

Symptoms of asthma based on questionnaire responses were statistically more prevalent among the exposed workers. The respiratory flow rates MEF25 and MEF50, which refer to smaller airways, were significantly lower among the smoking exposed workers than among the smoking unexposed workers. The causative factors of these symptoms and pulmonary function changes could not be determined by the study. One new case of cobalt asthma and one case of allergic asthma were diagnosed in the exposed population. No cases of hard metal disease or fibrosing alveolitis were found.

Conclusions

No chronic respiratory diseases, except asthma, were found among cobalt production workers in this study. Am. J. Ind. Med. 44:124–132, 2003. © 2003 Wiley‐Liss, Inc.
The study of things I have never seen
Authors: Bernstein Irwin S.
Published: July 2003

Tinbergen defined structure as the momentary condition of an organism. Inference, interpretation, and theory were reserved for answering the “why” questions. Mason, however, observed that the study of behavior is incorrigibly mentalistic. Description seems barren compared to the richness supplied by creative intelligence. Exciting intervening variables such as learning, intention, and selective pressures can only be examined using inference, logic, and powerful deductive theories. For more than 100 years people have argued the two extremes: should science be restricted to the directly observable, or expanded to include what professional judgment could provide? I have devoted my life to the study of aggression and dominance, yet I have directly observed neither. I point to some behavior as an example of aggression, but I cannot provide an operational definition of what I mean. I will never know if another intends harm. I will never know if another is aware of the functions that behavior serves, and the outcomes that I confuse with past selective pressures and motivation. In a world where our subjects face extinction, perhaps it is wise to use computer simulations, to ask colleagues to rate their impressions, and to use logic to deduce behavior. The new “data” may be very useful. Still, I will miss actually watching what animals really do, even if I always describe it in terms of what I infer. Am. J. Primatol. 60:77–84, 2003. © 2003 Wiley‐Liss, Inc.
Chromosome painting shows that the proboscis monkey (Nasalis larvatus) has a derived karyotype and is phylogenetically nested within asian colobines
Authors: Bigoni F , Stanyon R , Wimmer R , Schempp W
Published: July 2003

The exceptional diploid number (2n=48) of the proboscis monkey (Nasalis larvatus) has played a pivotal role in phylogenies that view the proboscis monkey as the most primitive colobine, and a long‐isolated genus of the group. In this report we used molecular cytogenetic methods to map the chromosomal homology of the proboscis monkey in order to test these hypotheses. Our results reveal that the N. larvatus karyotype is derived and is not primitive in respect to other colobines (2n=44) and most other Old World monkeys. The diploid number of 2n=48 can be best explained by derived fissions of a segment of human chromosomes 14 and 6. The fragmentation and association of human chromosomes 1 and 19 as seen in other Asian colobines, but not in African colobines, is best explained as a derived reciprocal translocation linking all Asian colobines. The alternating hybridization pattern between four segments homologous to human chromosomes 1 and 19 on N. larvatus chromosome 6 is the result of the reciprocal translocation followed by a pericentric inversion. N. larvatus shares this pericentric inversion with Trachypithecus, but not with Pygathrix. This inversion apparently links Nasalis and Trachypithecus after the divergence of Pygathrix. The karyological data support the view that Asian colobines, including N. larvatus, are monophyletic. They share many linking karyological features separating them from the African colobines. The hybridization pattern also suggests that Nasalis is nested within Asian Colobines and shares a period of common descent with other Asian colobines after the divergence of Pygathrix. Am. J. Primatol. 60:85–93, 2003. © 2003 Wiley‐Liss, Inc.
Mikrobläschen als Kontrastmittel für die diagnostische Ultraschall‐Bildgebung: die Schlüsselrolle von Perfluorverbindungen
Authors: Schutt Ernest G. , Klein David H. , Mattrey Robert M. , Riess Jean G.
Published: July 2003

Mikrometergroße Gasbläschen, die bei den für diagnostische Zwecke genutzten Ultraschallfrequenzen als Resonator fungieren, sind effektive Kontrastmittel für die Ultrasonographie. Doch einfache Luftbläschen lösen sich nach der Injektion in die Blutbahn innerhalb weniger Sekunden auf. Erst Fluorkohlenwasserstoffe, die die Lebensdauer der Mikrobläschen in vivo von Sekunden auf Minuten erhöhen, machten die Kontrast‐Ultrasonographie zu einer klinisch einsetzbaren Technik. Durch selektives Unterdrücken der Gewebesignale erhält man noch kontrastreichere Bilder. Zugelassen sind bisher C3F8‐ und SF6‐Mikrobläschen sowie N2‐Mikrobläschen, die osmotisch durch C6F14 stabilisiert sind. Mit ihnen lassen sich kardiovaskuläre Anomalitäten und Organschäden wie Tumore nachweisen und charakterisieren. Die so erhaltenen genauen Bilder tragen zu zuverlässigeren Diagnosen bei; damit kann dieser Technik eine entscheidende Rolle bei der klinischen Entscheidungsfindung zukommen. Neue Forschungsziele sind Mikrobläschen, die bestimmte Zellen ansteuern – sowohl für die Untersuchung einer Erkrankung als auch für die Wirkstoff‐Freisetzung und den Gentransport.
Titelbild: Hochgeordnete Merocyanin‐Farbstoffaggregate durch supramolekulare Polymerisation und hierarchische Selbstorganisation (Angew. Chem. 28/2003)
Authors: Würthner Frank , Yao Sheng , Beginn Uwe
Published: July 2003

Hierarchische Selbstorganisation des im Titelbild gezeigten Bis(merocyanins) führt auf der ersten Stufe zu helicalen Polymeren (oben), die sich in Methylcyclohexan zu stabförmigen Aggregaten (Mitte rechts) zusammenlagern. Diese ordnen sich bei höherer Konzentration schließlich zu einer hexagonal dichten Packung (unten). Wie F. Würthner et al. in ihrer Zuschrift auf S. 3368 ff. beschreiben, entstehen dabei Gele und flüssigkristalline Filme mit der im Hintergrund dargestellten ungewöhnlichen Textur.
Injectable Microbubbles as Contrast Agents for Diagnostic Ultrasound Imaging: The Key Role of Perfluorochemicals
Authors: Schutt Ernest G. , Klein David H. , Mattrey Robert M. , Riess Jean G.
Published: July 2003

Ultrasonography has, until recently, lacked effective contrast‐enhancing agents. Micrometer‐sized gas bubbles that resonate at a diagnostic frequency are ideal reflectors for ultrasound. However, simple air bubbles, when injected into the blood stream, disappear within seconds through the combined effects of Laplace pressure, blood pressure, and exposure to ultrasound energy. Use of fluorocarbon vapor, by extending the persistence of microbubbles in vivo from seconds to minutes, propelled contrast ultrasonography into clinical practice. Imaging techniques that selectively suppress tissue, but not microbubble signal, further increase image contrast. Approved products consist of C3F8 or SF6 microbubbles, and N2 microbubbles osmotically stabilized with C6F14. These agents allow the detection and characterization of cardiovascular abnormalities and solid organ lesions, such as tumors. By providing higher quality images, they improve the accuracy and confidence of disease diagnosis, and can play a decisive role in clinical decision making. New objectives include agents that target specific cells for the molecular imaging of disease, and drug and gene delivery, including ultrasound‐triggered delivery.
Chemistry—A Central Pillar of Human Culture
Authors: Shaik Sason
Published: July 2003

Chemistry is the intellectual adventure of Mankind in his excursion through his own material being. As this journey unfolds, so Mankind discovers the complex connection between matter and its emergent spiritual manifestations. Chemistry defines the limitation of the power over matter, and exemplifies this limitation by, for example, pollution and chemical warfare. Ruling over matter means also mastering the right ways of tinkering with it. These and other aspects of our science are discussed in this essay.
Ultradrawing properties of gel films of ultrahigh‐molecular‐weight polyethylene and low‐molecular‐weight polyethylene blends prepared at various formation temperatures
Authors: Yeh Jen‐Taut , Lin Yue‐Tang , Chen Kan‐Nan
Published: July 2003

The ultradrawing behavior of ultrahigh‐molecular‐weight polyethylene/low‐molecular‐weight polyethylene film specimens prepared at various concentrations and formation temperatures was studied. The critical draw ratio (Drc) of UL−0.7 film specimens was found to depend significantly on the formation temperature used to prepare the film specimens. At any fixed drawing temperature, the Drc values of UL−0.7 specimens prepared at various formation temperatures increased significantly as the formation temperatures were reduced. In fact, with an optimum drawing temperature of 95°C, the Drc values of UL−0.7 specimens prepared at a formation temperature of 0°C reached 488, about 50% higher than that of UL−0.7 specimens prepared at a formation temperature of 95°C. These interesting phenomena were investigated in terms of the thermal, birefringence, and tensile properties of these undrawn and drawn UL−0.7 specimens. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3728–3738, 2003
Composites based on eucalyptus tar pitch/castor oil polyurethane and short sisal fibers
Authors: Melo Breno N. , Pasa Vânya M. D.
Published: July 2003

Polymeric materials are being developed with renewable resources to promote industrial progress with environmentally friendly technologies. For this reason, polyurethane samples were prepared with 4,4′‐diphenylmethane diisocyanate (NCO/OH = 1), eucalyptus tar pitch (biopitch), castor oil as a polyol, and dibutyltin dilaurate as a catalyst. These materials were reinforced with different contents of short sisal fibers (0, 2.5, 5.0, 7.5, and 10.0%) and were prepared by resin‐transfer molding. The composites were characterized by IR absorption spectroscopy, thermal analysis (thermogravimetry and differential scanning calorimetry), impact resistance, scanning electron microscopy, and water absorption resistance. These materials showed hydrophobic characteristics, despite the addition of sisal fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3797–3802, 2003
Study on the curing process of QY8911‐3 resin
Authors: Yang De'an , Li Zhaoyang , Lu Yan , Xu Tingxian
Published: July 2003

The effect of t‐butyl peroxybenzoate (TBPB) on the cure reaction of QY8911‐3 resin (BMI) was studied by differential scanning calorimetry (DSC) and gel time analysis. The mechanical properties of the resin and the composite were tested and analyzed with the peroxide content. The results showed that TBPB decomposed between 117 and 191°C and the enthalpy was 1123 J/g. TBPB reduced the initial reaction temperature, prompted the reaction speed, and shortened the gel time of the BMI resin. TBPB also increased the bending strength and decreased the impacting strength of the postcured samples. So, the peroxide content should be less than 0.6%. CF/SiO2/BMI composites were prepared from the BMI containing peroxide and their microstructure and properties were better than those of the composites free of peroxide. According to the injection‐molding experiment, the spilling problem was overcome and the forming time was reduced from 2 h to 15 min when peroxide was added. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3769–3773, 2003
Toughening of polylactide by melt blending with linear low‐density polyethylene
Authors: Anderson Kelly S. , Lim Shawn H. , Hillmyer Marc A.
Published: July 2003

Melt blending of polylactide and linear low‐density polyethylene (LLDPE) was performed in an effort to toughen polylactide. In addition, two model polylactide‐polyethylene (PLLA‐PE) block copolymers were investigated as compatibilizers. The LLDPE particle size and the impact resistance of binary and ternary blends were measured to determine the extent of compatibilization. For the amorphous polylactide (PLA), toughening was achieved only when a PLLA‐PE block copolymer was used as a compatibilizer. For the semicrystalline polylactide (PLLA), toughening was achieved in the absence of block copolymer. To decrease the variability in the impact resistance of the PLLA/LLDPE binary blend, as little as 0.5 wt % of a PLLA–;PE block copolymer was effective. The differences that were seen between the PLA and PLLA binary blends were investigated with adhesion testing. The semicrystalline PLLA did show significantly better adhesion to the LLDPE. We propose that tacticty effects on the entanglement molecular weight or miscibility of polylactide allow for the improved adhesion between the PLLA and LLDPE. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3757–3768, 2003
Epoxy/alumina nanoparticle composites. I. Dynamic mechanical behavior
Authors: Vassileva E. , Friedrich K.
Published: July 2003

We studied the influence that alumina nanoparticle addition has on the dynamic mechanical spectra of an amino‐cured epoxy resin. A suppression of the short‐scale cooperative motions related to the β relaxation and an increase in the activation energy for the β relaxation of the epoxy matrix was observed as the alumina content increased. This is explained in terms of an antiplasticization effect of the alumina nanoparticles on the epoxy resin. An estimation of the effective thickness of the nanoparticle–matrix interfacial region was done based on the reduced damping. The dependence of the composites' reduced modulus on the alumina nanoparticles content is very well fitted by the generalized Kerner equation. The best‐fit parameter values suggest the presence of small and strong agglomerates in the composites at room temperature. At temperatures above the Tg, these agglomerates start to behave as weak ones because of the polymer matrix softening and particle–particle and particle–matrix slippage and friction. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3774–3785, 2003
Synthesis and characterization of organosoluble poly(arylate‐imide)s prepared from direct polycondensation of bis(trimellitimide)‐diacids and various bisphenols
Authors: Yang Chin‐Ping , Chiang Hsun‐Ching , Chen Ruei‐Shin
Published: July 2003

Three diimide‐diacids, 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]hexafluoropropane (I‐A), 2,2‐bis[4‐(4‐trimellitimidophenoxy)phenyl]propane (I‐B), and 5,5′‐bis[4‐ (4‐trimellitimidophenoxy)phenyl]hexahydro‐4,7‐methanoindan (I‐C), were prepared by the azeotropic condensation of trimellitic anhydride with three analogous diamines. Three series of alternating aromatic poly(arylate‐imide)s, having inherent viscosities of 0.41–0.82 dL/g, were synthesized from these diimide‐diacids (I‐A, I‐B, and I‐C) with various bisphenols by direct polycondensation using diphenyl chlorophosphate and pyridine as condensing agents. All of the polymers were readily soluble in a variety of organic solvents such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, and even in the less polar tetrahydrofuran. These polymers could be cast into transparent and tough films, which had strength at break values ranging from 73 to 98 MPa, elongation at break from 6 to 11%, and initial modulus from 1.6 to 2.2 GPa. The softening temperatures of the polymers were recorded at 145–248°C. They had 10% weight loss at a temperature above 450°C and left 35–51% residue even at 800°C in nitrogen. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3818–3825, 2003
Effect of polymer microstructure on dye diffusion in polyamide 66 fibers
Authors: Vasanthan Nadarajah , Huang Xin‐Xian
Published: July 2003

Our previous work showed that drawing polyamide 66 (PA 66) fibers at room temperature does not change the degree of crystallinity, but only increases the molecular orientation. We therefore have used a series PA 66 fibers with different draw ratios to establish a direct correlation between (noncrystalline) molecular orientation fa and the dye diffusion coefficient D. For both acid and disperse dyes, the relationship log D ∝ f provides reasonable fits to the data for PA 66 fibers, and a similar relationship appears to be applicable to PA 6 fibers. Heat‐setting the fibers results in a continuous decrease in diffusion coefficient; unlike PA6 and PET fibers, no minimum in D was found in the region of 160°C. If this decrease in D is attributed to the increase in volume fraction crystallinity X taking place during heat‐setting, it must be deduced that log D ∝ X6. This dependence is surprisingly strong, but is consistent with observations we have made on PET and PA6 fibers. It is possible that some other structural rearrangement is partially or largely responsible for the decrease in diffusion coefficient, but Fourier transform infrared, density, and X‐ray diffraction measurements do not indicate any other structural changes taking place. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3803–3807, 2003
Thermal properties relevant to the processing of PET fibers
Authors: De Clerck K. , Rahier H. , Van Mele B. , Kiekens P.
Published: July 2003

The thermal properties of poly(ethylene terephthalate) (PET) conventional fibers and microfibers are measured and compared to bulk samples. It is shown that the glass transition temperature (Tg) of the fibers can be monitored with modulated differential scanning calorimetry (MDSC). The Tg region is about 30°C wide and shifted to approximately 110°C for conventional as well as for micro‐PET fibers. The Tg of these fibers is compared to the Tg of cold‐crystallized bulk samples. Upon crystallization, a shift and even a split up of Tg is observed. The second Tg is much broader and is situated around 90°C. This Tg is related to the appearance of a rigid amorphous phase. In comparison, the mobility of the amorphous phase in fibers is even more restricted. The whole multiple melting profile observed on the fibers is the result of a continuous melting and recrystallization process, in contrast to bulk PET. The heat‐set temperature is shown to trigger the start of melting and recrystallization. It is seen in the MDSC as an exotherm in the nonreversing signal and an excess contribution in the heat‐capacity signal. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3840–3849, 2003
Simulation of continuous solid‐phase polymerization of nylon 6,6. III. Simplified model
Authors: Yao K. Zhen , McAuley Kim B. , Marchildon E. Keith
Published: July 2003

Solid‐phase polymerization (SPP) reactors are used to increase the degree of polymerization (DP) during nylon 6,6 production. In previous articles, a reactor model with partial differential equations (PDEs) in time and two spatial dimensions was developed to describe dynamic changes in polymer property profiles (DP, temperature, and moisture content) over the height of the reactor and within the polymer particles. In the current article, a simplified model is developed by deriving appropriate expressions for heat‐ and mass‐transfer coefficients and performing a lumped heat‐ and mass‐transfer analysis. Using this approach, the radial dimension is removed from the PDEs, so that the effort required to solve the model equations is substantially reduced. Predictions of the complex and simplified models are compared through simulation of two different start‐up processes. Good agreement between simplified and complex models is obtained, indicating that the simplified model can be used in place of the complex model if the polymer properties profiles within individual particles are not of particular concern to the model user. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3701–3712, 2003
Evaluating chitosan/β‐tricalcium phosphate/poly(methyl methacrylate) cement composites as bone‐repairing materials
Authors: Ming Kuo Shyh , Jen Chang Shwu , Lin Li‐Chun , Jung Chen Ching
Published: July 2003

This study related to the preparation of chitosan microspheres by means of reacting chitosan with β‐tricalcium phosphate (β‐TCP) and glutaraldehyde by crosslinking reaction in the oil phase, followed by de‐oil and purification processes to get the product. Three cement composites, Pure P, C1P1, and C2P1, were prepared by the polymerization of poly(methyl methacrylate) (PMMA) bone cement in the presence of 0, 50, and 66.7% chitosan/β‐TCP microspheres, respectively. The result revealed the chitosan/β‐TCP microspheres obtained was in the size range of 50–150 μm. The presence of chitosan/β‐TCP microspheres in the prepared composites decreased the ultimate tensile strength, whereas the modulus remained the same as compared with the commercial PMMA bone cement. Addition of chitosan/β‐TCP microspheres into commercial PMMA cement significantly improved the handling property of the cement paste—that is, the increased setting time and less stickiness behavior of this paste was beneficial, in manipulation, to the operation and easier fittings to the shape and gap of the bony defect and interface. The decreased curing temperature was also less harmful to the surrounding tissues. From scanning electron micrograph observations, chitosan/β‐TCP microspheres can completely mix with bone cement powder and the prepared composites could provide scaffold for osteoblast cells growth and thus improve defects of commercial PMMA bone cement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3897–3904, 2003
Photosensitizing properties of ionic porphyrins immobilized on functionalized solid polystyrene support
Authors: Johnson Inbaraj J. , Vinodu Mikki V. , Gandhidasan R. , Murugesan R. , Padmanabhan M.
Published: July 2003

The photogeneration of singlet oxygen (1O2) by tetrasodium salt of meso‐tetrakis(4‐sulfonatophenyl)porphyrins (H2TPPS) and some of its metal complexes (MTPPS; M = Cd2+, Zn2+), immobilized on cationically functionalized polystyrene (PS) beads, was studied. The generation of 1O2 was monitored by a N,N‐dimethyl‐4‐nitrosoaniline (RNO) bleaching assay. The rate of RNO bleaching was seen to be retarded in the presence of DABCO, a specific 1O2 scavanger, providing evidence for the involvement of 1O2 as an active intermediate. The relative efficiencies of the generation of 1O2, with respect to immobilized rose bengal (PS–RB), by different polymer‐supported porphyrins, were determined to be 0.29, 0.27, and 0.16 for PS–H2TPPS, PS–ZnTPPS, and PS–CdTPPS, respectively. Binding of porphyrins to a polymer has been found to decrease the efficiency of the 1O2 generation, which could be attributed to the structural deformation of the appended porphyrins. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3925–3930, 2003
Studies on acrylic acid–grafted polyester fabrics by electron beam preirradiation method. I. Effects of process parameters on graft ratio and characterization of grafting products
Authors: He Chengcheng , Gu Zhenya
Published: July 2003

Polyester fabrics were preirradiated by electron beam in air and then grafted by acrylic acid (AA) without excluding oxygen. Effects of preirradiation dose, monomer concentration, reaction temperature, storage time, sulfuric acid, and Mohr's salt were investigated in detail and are discussed. The results suggest that it is practicable and effective to graft AA onto polyester fabrics by means of the preirradiation method. FTIR and SEM were used to characterize AA‐grafted polyester fabrics. A new band appearing at 1546 cm−1 in the FTIR spectrum implies that AA was indeed introduced onto PET macromolecules. Changes of the diameter and the surface structure of fabric fibers presented in SEM micrographs make it clear that a layer of grafted poly(acrylic acid) was formed on the surface of these PET fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3931–3938, 2003
Kinematics of 11 Bidelman's weak‐lined stars
Authors: Bartkevičius A. , Sperauskas J.
Published: July 2003

Radial velocities obtained with the CORAVEL‐type spectrometer are presented for 11 Bidelman's weak‐lined stars, classified from moderate dispersion objective prism spectra. Standard errors of the measurements are smaller than 1 km/s. For five of these stars, measured in the Vilnius photometric system, only small metal deficiency is established. Kinematically, most of the stars belong to the thin disk and only two stars, HD 71185 and BD +75° 641, are consistent with membership of the thick disk population.
Interstellar polarization towardMKN421
Authors: Weitenbeck A.J.
Published: July 2003

Interstellar polarization in the direction of MKN421 reaches a value between .1% and .2% at a distance of 600 pc.