bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison Between Hydroperoxides and Malondialdehyde as Markers of Acute Oxidative Injury During Hemodialysis
Authors: Lucchi Leonardo , Iannone Anna , Bergamini Stefania , Stipo Lucia , Perrone Salvatore , Uggeri Simona , Gatti Valentina , Ferrari Federica , Tomasi Aldo , Albertazzi Alberto
Published: September 2005

Abstract:  An increased free‐radical production has been documented during hemodialysis (HD) particularly when bio‐incompatible membranes are utilized. These highly reactive free radicals can cause damage through several pathways, one of the best known being lipid peroxidation. Malondialdehyde (MDA) is a product of lipid peroxidation, which can partly be removed by HD due to its low molecular weight and water solubility. Hydroperoxides are predominantly found in lipid substances, and therefore their removal by HD could be difficult. We evaluated the behavior of these two by‐products of lipid peroxidation during HD, comparing their behavior in three different membranes, in order to study their reliability as markers of acute oxidative injury. Fifteen stable HD patients were dialyzed with each of the following membranes: cuprophan, polyamide, and polysulfone, three sessions for every membrane. MDA and hydroperoxides were measured pre‐HD and then both from the arterial and venous line at 8, 15, 30, and 240 min. During HD with cuprophan membrane MDA decreased significantly in the venous line compared with the arterial line at 8, 15, and 30 min (P < 0.05). At the end of HD, MDA was significantly reduced compared with MDA pre‐HD (P < 0.05). Plasma hydroperoxides increased significantly in the venous line compared with the arterial line at 8, 15, 30, and 240 min (P < 0.05). At the end of HD, hydroperoxides had increased significantly as compared with pre‐HD (P < 0.05). When the polyamide and polysulfone membranes were used, the behavior of MDA was similar to that found with cuprophan. Hydroperoxides were unchanged during HD using both membranes. MDA is not a reliable marker of acute oxidative injury during HD as it is removed during HD. Hydroperoxide measurement is a better marker of acute oxidative injury during HD.
Flow‐induced Platelet Activation in a St. Jude Mechanical Heart Valve, a Trileaflet Polymeric Heart Valve, and a St. Jude Tissue Valve
Authors: Yin Wei , Gallocher Siobhain , Pinchuk Leonard , Schoephoerster Richard T. , Jesty Jolyon , Bluestein Danny
Published: September 2005

Abstract:  Polymer heart valves have been under investigation since the 1960s, but their success has been hampered by an overall lack of durability mainly due to calcification of the leaflets and a relatively high rate of thromboembolic complications. A new polymer (Quatromer) trileaflet design was tested for its thrombogenic potential and was compared to that of existing prosthetic heart valves routinely implanted in patients: a St. Jude Medical bileaflet mechanical heart valve (MHV) and a St. Jude porcine bioprosthetic tissue valve. The valves were mounted in a left ventricular assist device and the procoagulant activity of the platelets was measured using a platelet activation state (PAS) assay. The PAS measurements indicated that the platelet activation level induced by the polymeric valve was very similar to that induced by the St. Jude Medical MHV and the St. Jude tissue valve. No significant difference was observed between the three valves, indicating that they have a comparable thrombogenic potential.
Magnevad Status of Design Improvements Human Blood Results and Preliminary Sheep Trial
Authors: Goldowsky Michael , Lafaro Rocco , Reed George
Published: September 2005

Abstract:  Magnevad II is an improved version of Magnevad I and both are fourth‐generation axial flow left ventricular assist devices. A major simplification has been implemented and tested. Magnevad I used a magnetically suspended rotor requiring active axial control. Magnevad II is completely passive but otherwise similar. A self‐washing radial hydrodynamic bearing suspends the rotor. In the axial direction, noncontact axial stiffness is provided by opposing pairs of repulsion magnets (called bumper magnets). Rotor location shifts in response to differential pressure. A low‐cost position sensor measures this motion to provide pump differential pressure. This is used to create pulsating flow and physiologic control (like Magnevad I). Hemolysis of Magnevad II using human blood was very low with a normalized index of hemolysis at 0.001–0.002 g/100 L. Our first sheep trial took place in September 2004. No thrombus or deposits were found in the disassembled pump. Longer sheep trials are scheduled in March 2005 at the Foundation Cardio‐Infantil in Bogota, Colombia.
Long‐term transfusion of polymerized bovine hemoglobin in a Jehovah's Witness following chemotherapy for myeloid leukemia: a case report
Authors: Agrawal Yash P. , Freedman Matthew , Szczepiorkowski Zbigniew M.
Published: September 2005

A 52‐year‐old female Jehovah's Witness presented with relapsed secondary acute myeloid leukemia. Because of chemotherapy‐induced anemia, she was infused with the bovine hemoglobin (Hb)‐based oxygen carrier HBOC‐201 (Biopure) as the sole means of transfusion support. HBOC‐201 has only been used for management of acute hemorrhage, and its utility in providing longer term transfusion support is unknown. Over a period of 18 days, a total dose of 1230 g of HBOC‐201 was delivered. Although the patient succumbed to the disease after 18 days of treatment, this case documents our experience with the highest dose and duration of HBOC‐201 ever used. Although possible renal toxicity could not be definitively excluded, the homogeneous extraction of oxygen by the brain in the presence of and perhaps from HBOC‐201 was demonstrated.
Bicarbonate inhibits the growth of Staphylococcus epidermidis in platelet concentrates by lowering the level of non‐transferrin‐bound iron
Authors: Matinaho Sanna , Karhumäki Paulina , Parkkinen Jaakko
Published: September 2005

BACKGROUND: Platelet concentrates (PCs) contain non‐transferrin‐bound iron (NTBI) owing to the displacement of iron from plasma‐derived transferrin by citrate. NTBI in the PC medium supports the growth of Staphylococcus epidermidis. The possibilities of lowering the level of NTBI have been studied with the aim to inhibit the growth of S. epidermidis in the PC medium.

STUDY DESIGN AND METHODS: NTBI in PC supernatants was determined by a chelation method and by the bleomycin‐detectable iron assay. Iron binding by transferrin was determined by spectrophotometry. The growth of inoculated S. epidermidis in PC supernatants was monitored by optical density and determination of viable counts.

RESULTS: Bicarbonate enhanced in a dose‐dependent manner transferrin iron binding in citrate‐containing solutions, including citrated plasma and PAS‐II. The use of a modified anticoagulant supplemented with bicarbonate effectively lowered the level of NTBI and inhibited bacterial growth in citrated plasma. Supplementation of bicarbonate to the additive solution to increase the ratio of bicarbonate to citrate in a reconstituted PC medium further inhibited bacterial growth. Maintenance of stable pH and bicarbonate level in the reconstituted medium necessitated storage under 5 percent CO2.

CONCLUSIONS: The relatively low bicarbonate level in PC medium promotes iron displacement by citrate from plasma‐derived transferrin. The appearance of NTBI can be decreased and iron‐dependent bacterial growth can be inhibited by increasing bicarbonate level in citrated plasma and PC medium. To achieve the same beneficial effect in blood banking, other more practical ways to bind NTBI in a harmless form should be developed.
Treatment with C1 inhibitor concentrate in abdominal pain attacks of patients with hereditary angioedema
Authors: Bork Konrad , Meng Gabriele , Staubach Petra , Hardt Jochen
Published: September 2005

BACKGROUND: Abdominal edema attacks in patients with hereditary angioedema are often extremely painful, associated with vomiting and diarrhea, and have a high potential for causing recurrent disability of the patient.

STUDY DESIGN AND METHODS: Intraindividual comparison of retrospective data in 75 hereditary angioedema patients comprising 4,834 abdominal attacks treated with C1 inhibitor concentrate versus 17,444 untreated abdominal attacks.

RESULTS: The mean duration of abdominal attacks was 92.0 hours (SD, 40.8 hr) when untreated compared to 39.9 hours (SD, 30.0 hr) when treated. Patients reported a mean maximal pain score of 8.6 (SD, 1.7; range, 1‐10) for untreated attacks compared to 4.5 (SD, 2.9) when treated. Vomiting occurred in 83.3 percent of untreated attacks and in 6.0 percent of treated attacks, respectively. Diarrhea was reported in 41.8 percent of untreated attacks and in 11.0 percent of treated attacks, whereas cardiovascular collapse due to hypovolemia was observed in 3.5 percent of untreated attacks versus 0.1 percent in treated attacks. Mean time to relief of symptoms was 53.5 minutes when treated early compared to 114 minutes when treatment was delayed. No drug‐related adverse or serious adverse events were observed as far as the injections were performed correctly.

CONCLUSION: C1 inhibitor concentrate is highly effective and safe in treating abdominal attacks in patients suffering from hereditary angioedema.
Beneficial effect of transfusion with low‐affinity red blood cells in endotoxemia
Authors: Huang Fei , Nojiri Hidetoshi , Shimizu Takahiko , Shirasawa Takuji
Published: September 2005

BACKGROUND: Sepsis caused by endotoxins such as lipopolysaccharide (LPS) impairs the microcirculation, diminishing tissue blood supply and aggravates systemic hypoxia. A novel lower‐affinity hemoglobin (Hb) variant, Hb Presbyterian, enhances oxygen release to peripheral tissues and may improve tissue oxygen supply during sepsis.

STUDY DESIGN AND METHODS: This study investigated the effectiveness of Presbyterian Hb in transfusion therapy with LPS‐challenged sepsis mouse model. Septic wild‐type mice were transfused with RBCs from Presbyterian Hb–carrying mutant mice and wild‐type mice. Their survival rates were assessed, and apoptosis of hepatocytes was evaluated. Survival rates of septic Presbyterian mutant mice and the wild‐type littermates were also studied.

RESULTS: The Presbyterian mutant RBC–transfused septic group survived longer than the wild‐type RBC–transfused group. Apoptosis was reduced in the hepatocytes of the former group. Presbyterian mutant mice themselves, however, did not have stronger resistance to LPS‐induced sepsis.

CONCLUSION: Transfusion of low‐affinity Hb‐containing RBCs has beneficial effects in septic mice.
Improvisation and Mediation: Balancing Acts
Authors: Balachandra Lakshmi , Barrett Frank , Bellman Howard , Fisher Colin , Susskind Lawrence
Published: September 2005

Improvisation can be an important element of mediation practice, and there are several ways in which mediation practice correlates to improvisational performance. In this article, two mediation experts and two skilled jazz musicians explore the improvisational aspects of mediation. Two central themes emerge: (1) mediators often use improvisational techniques, and (2) by being improvisational, mediators can create environments that would encourage the parties themselves to be improvisational. We argue that practitioners can enhance their effectiveness as mediators by mastering improvisational skills.
Improvisation and Teaching Negotiation: Developing Three Essential Skills
Authors: Balachandra Lakshmi , Crossan Mary , Devin Lee , Leary Kim , Patton Bruce
Published: September 2005

The notion of an adaptable negotiator, who can respond to any situation he or she encounters, resonates with every negotiation expert. Unexpected things happen in negotiation, and negotiators must be able to adapt in fleet and effective ways. Dealing with the unexpected, responding “in the moment,” and adapting effectively to sudden changes — these are the skills of an improvisational artist, and they are effective skills for negotiators to learn. How can improvisational skills be taught to negotiation students so that they will be able to draw upon these skills in the heat of a negotiation or mediation? By bringing together teachers of improvisation in various disciplines, we explored how improvisation is currently applied and taught in theater, business, and psychotherapy. We then developed some ideas about ways in which teachers of negotiation might begin to incorporate improvisation as part of the negotiation lesson plan.
Mediation within the French Industrial Relations Context: The SFR Cegetel Case
Authors: Rojot Jacques , Le Flanchec Alice , Landrieux‐Kartochian Sophie
Published: September 2005

This article examines the introduction of mediation in the French industrial relations context, as illustrated by the case of the SFR Cegetel collective agreement on social dialogue, which was signed in June 2002. This article provides an overview of relevant French legislation and explores why mediation is used so infrequently in France to settle labor conflicts, examines the growing interest in mediation in France as exemplified in the implementation of alternative dispute resolution (ADR) programs in several firms, and analyzes the barriers and incentives to mediation as well as the impact of internal mediation on the relations between management and employees.

We conclude that while inherited customs and lack of information curtail the use of mediation, disputants increasingly favor mediation as an option when they wish to gain time or when the situation is filled with especially acute open conflict. In addition, we conclude that the introduction of mediation favors a more participatory style of management, improves relationships between management and employees, and induces a better social dialogue within the firm.
Mediation in Italy: Exploring the Contradictions
Authors: De Palo Giuseppe , Harley Penelope
Published: September 2005

This article sets Italy in the context of three primary approaches to promoting mediation use in Europe: cultural, pragmatic, and legalistic. Despite the fact that Italy could be considered a “front‐runner” in the latter category, the actual number of cases going to mediation to date has remained low. Drawing on both data from a recent CPR European Committee survey and aspects of the broader Italian legal and social context, this article explores reasons for this apparent contradiction and concludes by suggesting general principles that can be extrapolated from the Italian experience.
Mediation Practice in the South African Construction Industry: The Influence of Culture, the Legislative Environment, and the Professional Institutions
Authors: Povey Althea , Cattell Keith , Michell Kathy
Published: September 2005

We studied mediation practice in the South African construction industry by surveying sixty‐three mediators. We found that mediators are more intent on resolving disputes for the parties than on assisting the parties to find their own settlements. In addition, we found that greater emphasis by parties to the dispute is placed on technical expertise, authority, and a clear understanding of the matter in dispute than on moving the parties toward an in‐depth understanding of each other's perspectives. We conclude that mediation practice in the South African construction industry is not consistent with generally accepted principles of mediation. We also argue that the fragmented and potentially adversarial traditional procurement system predominantly used in South Africa, together with the inadequate institutional response in promoting mediation as a preferred dispute resolution method, is encouraging mediation to develop in this way. This is cause for concern, not only because this practice represents a departure from the underlying philosophy of mediation — dialogue aimed at amicable and long‐lasting solutions that are in everyone's best interests — but because it is incompatible with the Southern African worldview concept of ubuntu.
Aging Down Under
Authors: Olshansky S. Jay
Published: September 2005

A new International Research Centre for Healthy Ageing and Longevity (IRCHAL) has been created in Australia with initial funding from a philanthropic family--that of John and Noah Weller. This center will be akin to the Center for Advanced Study at Stanford University where scientists and clinicians/geriatricians can spend extended time periods interacting and doing their research. The development of IRCHAL is an explicit effort to blend traditional scientific approaches to the study of aging with evidence-based natural and complementary medicine. At the heart of this new organization are annual international scientific conferences. The next meeting (third in the series) will be held in Melbourne, Australia, on 28 to 30 April 2006.
Error Prone
Authors: Davenport R. John
Published: September 2005

In the Tour de France, cycling teams can drop in the standings if individual riders lag. Similarly, mice that grow old prematurely might do so because some cells wither, according to a new study. The work suggests why one rodent line deteriorates quickly, although researchers need further evidence to nail down the cause.
Beta Testing
Authors: Leslie Mitch
Published: September 2005

If the manager at a fast-food joint always knocks off early, the other employees probably won't work very hard. Similarly, a "supervisor" gene that slacks off in pancreas cells might help trigger diabetes, a new study shows. Losing the gene thwarts the activity of other genes that control how the cells respond to glucose and release insulin. The work might provide a new target for antidiabetes drugs.
Family Feud
Authors: Davenport R. John
Published: September 2005

Siblings sometimes have contrasting personalities despite similar appearances. The tumor-preventing molecule p53 accelerates aging, but new results suggest that a related protein retards it. Mice without the protein, called p63, age unusually quickly, and their cells divide sluggishly. The findings bolster the notion that dwindling stem cell stores promote physical deterioration.
Interfering with Longevity
Authors: Lee Siu Sylvia
Published: September 2005

Several recent studies have highlighted how RNA interference has advanced aging-related research in
Caenorhabditis elegans
. Two new genome-wide RNAi-based screens together identified more than 100 new candidate longevity genes. RNAi has also greatly facilitated the functional validation of several large-scale gene expression profiling studies. Furthermore, RNAi is flexible and can be administered at different times throughout life; this feature has been exploited to analyze the temporal requirement of genes in life-span determination.
Transmission of Equine Influenza Virus to Dogs
Authors: Crawford P. C. , Dubovi Edward J. , Castleman William L. , Stephenson Iain , Gibbs E. P. J. , Chen Limei , Smith Catherine , Hill Richard C. , Ferro Pamela , Pompey Justine , Bright Rick A. , Medina Marie-Jo ,   Influenza Genomics Group, Johnson Calvin M. , Olsen Christopher W. , Cox Nancy J. , Klimov Alexander I. , Katz Jacqueline M. , Donis Ruben O.
Published: September 2005

Molecular and antigenic analyses of three influenza viruses isolated from outbreaks of severe respiratory disease in racing greyhounds revealed that they are closely related to H3N8 equine influenza virus. Phylogenetic analysis indicated that the canine influenza virus genomes form a monophyletic group, consistent with a single interspecies virus transfer. Molecular changes in the hemagglutinin suggested adaptive evolution in the new host. The etiologic role of this virus in respiratory disease was supported by the temporal association of rising antibody titers with disease and by experimental inoculation studies. The geographic expansion of the infection and its persistence for several years indicate efficient transmission of canine influenza virus among greyhounds. Evidence of infection in pet dogs suggests that this infection may also become enzootic in this population.
Glial Intercellular Waves
Authors: Charles Andrew
Published: September 2005

Glial cells have long been assigned a supporting role in the nervous system, in which they help maintain and modulate neuronal metabolism. However, recent attention has focused on the ability of astrocytes to propagate long-range calcium signals and actively communicate with each other, as well as with neurons and vascular cells. Synaptic activity in neurons triggers an increase in the intracellular calcium concentration ([Ca
2+
]
i
) of neighboring astrocytes, stimulating the release of ATP and glutamate. The released ATP stimulates an increase in [Ca
2+
]
i
in neighboring astrocytes so that a "calcium

wave" is propagated from cell to cell. Released glutamate is cotransported with Na
+
into neighboring cells; thus, glutamate uptake leads to an increase in astrocyte intracellular sodium concentration ([Na
+
]
i
) that is also propagated from cell to cell. This increase in [Na
+
]
i
stimulates an increase in glucose uptake and metabolism that leads to the formation of lactate, which is delivered to nearby--and perhaps distant--neurons as an energy substrate. Thus, long-range intercellular calcium signaling in astrocytes may enable them to spatially coordinate their function in supporting neuronal metabolism.
Signals from the Past
Authors: Ray L. Bryan , Adler Elizabeth M. , Gough Nancy R.
Published: September 2005

Science
’s
STKE
celebrates
Science
’s 125th anniversary issue by presenting 12 notable articles from
Science
that highlight different aspects of cell signaling research.
Host Cell Signaling and
Trypanosoma cruzi
Invasion: Do All Roads Lead to Lysosomes?
Authors: Burleigh Barbara A.
Published: September 2005

Trypanosoma cruzi
, the protozoan parasite that causes Chagas’ disease in humans, is capable of invading and replicating within a wide variety of nucleated mammalian cell types. Host cell invasion by infective
T. cruzi
trypomastigotes is governed by parasite-triggered activation of host cell signaling pathways. Recent studies highlighting a role for host cell phosphatidylinositol 3-kinases (PI3Ks) in the
T. cruzi
invasion process have revealed surprising new insights into the mechanism of host cell invasion by this pathogen. In this Perspective, we discuss these findings and propose alternative models of
T. cruzi
invasion that incorporate this new information.
R7BP: A Surprising New Link Between G Proteins, RGS Proteins, and Nuclear Signaling in the Brain
Authors: Hepler John R.
Published: September 2005

The regulators of G protein signaling (RGS proteins) bind directly to G protein alpha (Gα) subunits in brain and other tissues to determine the strength, duration, and fidelity of neurotransmitter receptor signaling. A recent study shows, quite unexpectedly, that one class of RGS proteins [the R7 subfamily bound to Gβ
5
(R7-Gβ
5
)] shuttles between the plasma membrane and the nucleus with assistance from a novel shuttle protein, R7BP. R7BP binds directly to R7-Gβ
5
and the protein complex is tethered to the plasma membrane by addition of a lipid, palmitate, on R7BP. Removal of palmitate results in the translocation of the R7BP–R7-Gβ
5
complex to the nucleus, presumably for nontraditional signaling functions. These findings suggest an entirely novel mechanism for regulating neurotransmitter signaling. That is, R7BP transduces signals directly from receptors and G proteins at the plasma membrane to the nucleus, and this plasma membrane–nuclear shuttling is controlled by reversible palmitoylation of R7BP.
Chromatin Remodeling
Authors: Lue Neal F.
Published: September 2005

This Teaching Resource provides lecture notes and slides for a class covering chromatin remodeling mechanisms and is part of the course "Cell Signaling Systems: a Course for Graduate Students." The lecture begins with a discussion of chromatin organization and then proceeds to describe the process of chromatin remodeling through a review of chromatin remodeling complexes and methods used to study their function.
TRP Channels in Disease
Authors: Nilius Bernd , Voets Thomas , Peters John
Published: September 2005

The mammalian TRP (transient receptor potential) family consists of six main subfamilies termed the TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), and TRPA (ankyrin) groups. These subfamilies encompass 28 ion channels that function as diverse cellular sensors. All of the channels are permeable to monovalent cations, and most are also permeable to Ca
2+
. There are strong indications that TRP channels are involved in many diseases. At this point, four channelopathies have been identified in which a defect in a TRP channel–encoding gene is the direct cause of disease. TRPs are also involved in some systemic diseases because of their role as receptors for irritants, inflammation products, and xenobiotic toxins. Other indications of the involvement of TRPs in several diseases come from correlations between the levels of channel expression and disease symptoms or from the mapping of TRP-encoding genes to susceptible chromosome regions. Finally, the phenotypes of TRP knockout mice and other transgenic models allow a degree of extrapolation to human diseases. We present an overview of current knowledge about the role of TRP channels in human disease and highlight some TRP "suspects" for which a role in disease can be anticipated. An understanding of the genetics of disease may lead to the development of targeted new therapies.
Histone Deacetylases as Transcriptional Activators? Role Reversal in Inducible Gene Regulation
Authors: Nusinzon Inna , Horvath Curt M.
Published: September 2005

Histone deacetylation enzymes have often been associated with the suppression of eukaryotic gene transcription. In contrast, recent studies of inducible gene regulation indicate that protein deacetylation can also be required as a transcriptional activation signal. The concept of protein deacetylation as a requirement for transcription activation seems to contradict earlier conclusions about the function of deacetylation in gene suppression. However, in the context of a more global interpretation, these opposing effects of deacetylation imply its dynamic role in the overall control of gene expression. The exact requirement for deacetylation differs among promoters, depending on their specific architecture and regulation scenario.
Checkpoints of Melanocyte Stem Cell Development
Authors: Sommer Lukas
Published: September 2005

The bulge region of the adult hair follicle contains the niches for both epithelial and melanocyte stem cells. Recent evidence suggests that the development of melanocyte stem cells is controlled by a complex network of transcription factors, including Pax3, Sox10, and Mitf, and of regulatory extracellular cues such as Wnt. However, additional players are likely to be involved. It will be intriguing to identify these signals and to elucidate whether and how neighboring epithelial stem cells influence the balance between melanocyte stem cell maintenance and differentiation.
A Journal-Club Discussion of Regulation by microRNA
Authors: Weinstein Daniel C.
Published: September 2005

Student analysis and discussion of the primary literature is an essential component to graduate education. In the context of a course on cell biology, signal transduction, or molecular biology, discussion of an article on microRNA function and importance would be valuable. This discussion was designed to accompany the course "Cell Signaling Systems: A Course for Graduate Students."
A Model for Local Regulation of Translation Near Active Synapses
Authors: Kosik Kenneth S. , Krichevsky Anna M.
Published: September 2005

Synaptic plasticity results in enduring changes in synaptic function. Localized protein synthesis is part of this process. This animation shows how a dynamic macromolecular structure, the RNA granule, may allow localized translation of proteins at the site of active synapses and thereby serve as a key element contributing to changes in protein production leading to synaptic plasticity. This animation would be useful in teaching a neurobiology or neuroscience course, where it could be used to illustrate mechanisms for activity-dependent protein translation, or in a biochemistry course or a molecular or cellular biology course, where it could be used to illustrate mechanisms governing regulation of protein translation.
Secondhand smoke and respiratory ill health in current smokers
Authors: Lam T-H , Ho L-M , Hedley A J , Adab P , Fielding R , McGhee S M , Leung G M , Aharonson-Daniel L
Published: September 2005

Background:Numerous studies have concluded that secondhand smoke (SHS) is harmful to non-smokers but controversy persists regarding its effects on smokers. The impact of SHS exposure on the acute respiratory health of current active smokers was examined using a cross sectional design.

Methods:9923 uniformed staff in the Hong Kong Police Force completed a standardised questionnaire on current and past smoking, SHS exposure at home and at work, acute respiratory symptoms, and recent physician consultation. 3999 male current smokers were included in the analysis.

Results:About 5% of the smokers were exposed to SHS at home only, 53% were exposed at work only, and 30% were exposed both at home and at work. The prevalence ratios for respiratory symptoms (throat and nasal problems, cough, phlegm, and wheeze), physician consultation, and self medication were higher for those who were exposed to SHS at home or at work. The odds ratios of reporting one or more respiratory symptoms, for SHS exposures at home or at work, were 1.33 (95% confidence interval (CI) 1.12 to 1.59) and 1.66 (95% CI 1.36 to 2.02) respectively, after adjusting for age, marital status, education, rank and duties, exposure to self perceived dusty or polluted environment in previous job, and total dose of active smoking. The adjusted odds ratios showed significant positive dose–response gradients with SHS exposure at home, at work, and at both places combined.

Conclusions:SHS exposure is strongly associated with increased acute respiratory symptoms and recent outpatient service utilisation in current smokers. If the association is causal, public health action to limit SHS exposure could also benefit smokers.
QUANTIZATION IN THE PRESENCE OF LARGE AMPLITUDE THRESHOLD NOISE
Authors: MCDONNELL MARK D. , STOCKS NIGEL G. , PEARCE CHARLES E. M. , ABBOTT DEREK
Published: September 2005

Signal quantization in the presence of independent, identically distributed, large amplitude threshold noise is examined. It has previously been shown that when all quantization thresholds are set to the same value, this situation exhibits a form of stochastic resonance known as suprathreshold stochastic resonance. This means the optimal quantizer performance occurs for a small input signal-to-noise ratio. Here we examine the performance of this stochastic quantization in terms of both mutual information and mean square error distortion. It is also shown that for low input signal-to-noise ratios that the case of all thresholds being identical provides the optimal mean square error distortion performance for the given noise conditions.
Positive cooperativity between the thrombin and bradykinin B2receptors enhances arachidonic acid release
Authors: Hecquet Claudie , Biyashev Dauren , Tan Fulong , Erdös Ervin G.
Published: September 2005

Bradykinin (BK) or kallikreins activate B2receptors (R) that couple Gαiand Gαqproteins to release arachidonic acid (AA) and elevate intracellular Ca2+concentration ([Ca2+]i). Thrombin cleaves the protease-activated-receptor-1 (PAR1) that couples Gαi, Gαq, and Gα12/13proteins. In Chinese hamster ovary cells stably transfected with human B2R, thrombin liberated little AA, but it significantly potentiated AA release by B2R agonists. We explored mechanisms of cooperativity between constitutively expressed PAR1 and B2R. We also examined human endothelial cells expressing both Rs constitutively. The PAR1 agonist hexapeptide (TRAP) was as effective as thrombin. Inhibitors of components of Gαi, Gαq, and Gα12/13signaling pathways, and a protein kinase C (PKC)-α inhibitor, Gö-6976, blocked potentiation, while phorbol, an activator, enhanced it. Several inhibitors, including a RhoA kinase inhibitor, a [Ca2+]iantagonist, and an inositol-(1,3,4)-trisphosphate R antagonist, reduced mobilization of [Ca2+]iby thrombin and blocked potentiation of AA release by B2R agonists. Because either a nonselective inhibitor (isotetrandrine) of phospholipase A2(PLA2) or a Ca2+-dependent PLA2inhibitor abolished potentiation of AA release by thrombin, while a Ca2+-independent PLA2inhibitor did not, we concluded that the mechanism involves Ca2+-dependent PLA2activation. Both thrombin and TRAP modified activation and phosphorylation of the B2R induced by BK. In lower concentrations they enhanced it, while higher concentrations inhibited phosphorylation and diminished B2R activation. Protection of the NH2-terminal Ser1-Phe2bond of TRAP by an aminopeptidase inhibitor made this peptide much more active than the unprotected agonist. Thus PAR1 activation enhances AA release by B2R agonists through signal transduction pathway.
Weak formulation of singular differential expressionsin spaces of functions with minimal derivatives
Authors: El-Gebeily M. A.
Published: September 2005

A weak formulation for singular symmetric differential
expressions is presented in spaces of functions which possess
minimal differentiability requirements. These spaces are used to
characterize the domains of the various operators associated with
such expressions. In particular, domains of self‐adjoint
differential operators are characterized.
Stability of conditionally invariant sets and controlleduncertain dynamic systems on time scales
Authors: Lakshmikantham V. , Drici Z.
Published: September 2005

A basic feedback control problem is that of obtaining some desired stability property from a system which contains uncertainties due to unknown inputs into the system. Despite such imperfect knowledge in the selected mathematical model, we often seek to devise controllers that will steer the system in a certain required fashion. Various classes of controllers whose design is based on the method of Lyapunov are known for both discrete [4], [10], [15], and continuous [3–9], [11] models described by difference and differential equations, respectively. Recently, a theory for what is known as dynamic systems on time scales has been built which incorporates both continuous and discrete times, namely, time as an arbitrary closed sets of reals, and allows us to handle both
systems simultaneously [1], [2], [12], [13]. This theory permits one to get some insight into and better understanding of the subtle differences between discrete and continuous systems. We shall, in this paper, utilize the framework of the theory of dynamic systems on time scales to investigate the stability properties of conditionally invariant sets which are then applied to discuss controlled systems with uncertain elements. For the notion of conditionally invariant set and its stability properties, see [14]. Our results offer a new approach to the problem in question.
A high‐precision algorithm for axisymmetric flow
Authors: Gokhman A. , Gokhman D.
Published: September 2005

We present a new algorithm for highly accurate computation of axisymmetric potential flow. The principal feature of the algorithm is the use of orthogonal curvilinear coordinates. These coordinates are used to write down the equations and to specify quadrilateral elements following the boundary. In particular, boundary
conditions for the Stokes′ stream‐function are satisfied exactly. The velocity field is determined by differentiating the stream‐function. We avoid the use of quadratures in the evaluation of Galerkin integrals, and instead use splining of the boundaries of elements to take the double integrals of the shape functions in closed form. This is very accurate and not time consuming.
On existence and uniqueness of the solution of the equation of motion for constrained mechanical systems
Authors: Udwadia Firdaus E. , Kalaba Robert E. , Nashed M. Zuhair
Published: September 2005

In this paper we provide sufficient conditions for the existence and uniqueness of the solution of the newly obtained equation of motion for constrained mechanical systems.
Feedback control of time‐delay systems with bounded control and state
Authors: Dambrine M. , Richard J. P. , Borne P.
Published: September 2005

This paper is concerned with the problem of stabilizing linear time‐delay systems under state and control linear constraints. For this, necessary and sufficient conditions for a given non‐symmetrical polyhedral set to be positively invariant are obtained. Then existence conditions of linear state feedback control law respecting the
constraints are established, and a procedure is given in order to calculate such a controller. The paper concerns memoryless controlled systems but the results can be applied to cases of delayed controlled systems. An example is given.
System‐theoretic analysis of due‐time performance in production systems
Authors: Jacobs David , Meerkov Semyon M.
Published: September 2005

Along with the average production rate, the due‐time performance is an important characteristic of manufacturing systems. Unlike the production rate, the due‐time performance has received relatively little attention in the literature, especially in the context of large volume production. This paper is devoted to this topic. Specifically,
the notion of due‐time performance is formalized as the probability that the number of parts produced during the shipping period reaches the required shipment size. This performance index is analyzed for both lean and mass manufacturing environments. In particular, it is shown that, to achieve a high due‐time performance in a lean
environment, the production system should be scheduled for a sufficiently small fraction of its average production rate. In mass production, due‐time performance arbitrarily close to one can be achieved for any scheduling practice, up to the average production rate.
Mathematical problems in modeling artificial heart
Authors: Ahmed N. U.
Published: September 2005

In this paper we discuss some problems arising in mathematical modeling of artificial hearts. The hydrodynamics of blood flow in an artificial heart chamber is governed by the Navier‐Stokes equation, coupled with an equation of hyperbolic type subject to moving boundary conditions. The flow is induced by the motion of a diaphragm
(membrane) inside the heart chamber attached to a part of the boundary and driven by a compressor (pusher plate). On one side of the diaphragm is the blood and on the other side is the compressor fluid. For a complete mathematical model it is necessary to write the equation of motion of the diaphragm and all the dynamic couplings that exist between its position, velocity and the blood flow in the heart chamber. This gives rise to a
system of coupled nonlinear partial differential equations; the Navier‐Stokes equation being of parabolic type and the equation for the membrane being of hyperbolic type. The system is completed by introducing all the necessary static and dynamic boundary conditions. The ultimate objective is to control the flow pattern so as to minimize hemolysis (damage to red blood cells) by optimal choice of geometry, and by optimal control of the membrane for a given geometry. The other clinical problems, such as compatibility of the material used in the construction of the heart chamber, and the membrane, are not considered in this paper. Also the dynamics of the valve is not considered here, though it is also an important element in the overall design of an artificial heart. We hope to model the valve dynamics in later paper.
Nonlinear singularly perturbed systems of differential equations: A survey
Authors: Slavova Angela
Published: September 2005

In this paper a survey of the most effective methods in singular perturbations is presented. Many applied problems can be modeled by nonlinear singularly perturbed systems, as, for example, problems in kinetics, biochemistry, semiconductors theory, theory of electrical chains, economics, and so on. In this survey we consider averaging and constructive methods that are very useful from the point of view of their numerical and computer realizations.
Assignment of nonlinear sampled‐data dynamics using generalized hold function control
Authors: Kabamba Pierre T. , Hung Yao-Shan
Published: September 2005

This paper considers the problem of assigning the dynamics of a nonlinear analytic system using nonlinear generalized sampled‐data hold function (GSHF) control, in the neighborhood of an equilibrium point. On every sampling interval, the control input consists of a nonlinear time‐periodic function applied to the sampled value
of the state vector. The nonlinear monodromy map is the state transition map from one sample time to the next. It is shown that this map is arbitrarily assignable by GSHF feedback if and only if the linear part of the system is controllable. Two approaches are proposed to construct a GSHF controller that performs the assignment. The
first approach matches the coefficients of the Taylor series expansion of the monodromy map around the equilibrium. The second approach interpolates an optimal control law at several points in the vicinity of the equilibrium. These approaches are illustrated on an example.
Frequency and distribution of chromosome abnormalities in human oocytes
Authors: Kuliev A. , Cieslak J. , Verlinsky Y.
Published: September 2005

It was previously shown that more than half of the human oocytes obtained from IVF patients of advanced reproductive age are aneuploid, due to meiosis I and meiosis II errors. The present paper further confirms that 61.8% of the oocytes tested by fluorescent probes specific for chromosomes 13, 16, 18, 21 and 22 are abnormal, representing predominantly chromatid errors, which are the major source of aneuploidy in the resulting embryos. Almost half of the oocytes with meiosis I errors (49.3%) are prone to sequential meiosis II errors, which may lead to aneuploidy rescue in 30.8% of the cases. Half of the detected aneuploidies (49.8%) are of complex nature with involvement of two or more chromosomes, or the same chromosome in both meiotic divisions. The aneuploidy rates for individual chromosomes are different, with a higher prevalence of chromosome 21 and 22 errors. The origin of aneuploidy for the individual chromosomes is also not random, with chromosome 16 and 22 errors originating more frequently in meiosis II, and chromosome 18, 13 and 21 errors in meiosis I. There is an age dependence not only for the overall frequency of aneuploidies, but also for each chromosome error, aneuploidies originating from meiosis I, meiosis II, and both meiosis I and meiosis II errors, as well as for different types of aneuploidies. The data further suggest the practical relevance of oocyte aneuploidy testing for detection and avoidance from transfer of the embryos deriving from aneuploid oocytes, which should contribute significantly to the pregnancy outcomes of IVF patients of advanced reproduction age.
Frequency and distribution of chromosome abnormalities in human spermatozoa
Authors: Templado C. , Bosch M. , Benet J.
Published: September 2005

This study reviews the frequency and distribution of numerical and structural chromosomal abnormalities in spermatozoa from normal men obtained by the human-hamster system and by multicolor-FISH analysis on decondensed sperm nuclei. Results from large sperm karyotyping series analyzed by chromosome banding techniques and results from multicolor FISH in sperm nuclei (of at least 104 spermatozoa per donor and per probe) were reviewed in order to establish baseline values of the sperm chromosome abnormalities in normal men. In karyotyping studies, the mean disomy frequency in human sperm is 0.03% for each of the autosomes, and 0.11% for the sex chromosomes, lower than those reported in sperm nuclei by FISH studies using a similar methodology (0.09% and 0.26%, respectively). Both types of studies coincide in that chromosome 21 and sex chromosomes have a greater tendency to suffer segregation errors than the rest of the autosomes. The mean incidence of diploidy, only available from multicolor FISH in sperm nuclei, is 0.19%. Inter-donor differences observed for disomy and diploidy frequencies among FISH studies of decondensed sperm nuclei using a similar methodology could reflect real differences among normal men, but they could also reflect the subjective application of the scoring criteria among laboratories. The mean frequency of structural aberrations in sperm karyotypes is 6.6%, including all chromosome types of abnormalities. Chromosome 9 shows a high susceptibility to be broken and 50% of the breakpoints are located in 9q, between the centromere and the 9qh+ region. Structural chromosome aberrations for chromosomes 1 and 9 have also been analyzed in human sperm nuclei by multicolor FISH. Unfortunately, this assay does not allow to determine the specific type of structural aberrations observed in sperm nuclei. An association between advancing donor age and increased frequency of numerical and structural chromosome abnormalities has been reported in spermatozoa of normal men.
Mechanisms of aneuploidy induction in human oogenesis and early embryogenesis
Authors: Delhanty J.D.A.
Published: September 2005

The mechanisms of aneuploidy induction in human oogenesis mainly involve nondisjunction arising during the first and second meiotic divisions. Nondisjunction equally affects both whole chromosomes and chromatids, in the latter case it is facilitated by “predivision” or precocious centromere division. Karyotyping and CGH studies show an excess of hypohaploidy, which is confirmed in studies of preimplantation embryos, providing evidence in favour of anaphase lag as a mechanism. Preferential involvement of the smaller autosomes has been clearly shown but the largest chromosomes are also abnormal in many cases. Overall, the rate of chromosomal imbalance in oocytes from women aged between 30 and 35 has been estimated at 11% from recent karyotyping data but accruing CGH results suggest that the true figure should be considerably higher. Clear evidence has been obtained in favour of germinal or gonadal mosaicism as a predisposing factor. Constitutional aneuploidy in embryos is most frequent for chromosomes 22, 16, 21 and 15; least frequently involved are chromosomes 14, X and Y, and 6. However, embryos of women under 37 are far more likely to be affected by mosaic aneuploidy, which is present in over 50% of 3-day-old embryos. There are two main types, diploid/aneuploid and chaotic mosaics. Chaotic mosaics arise independently of maternal age and may be related to centrosome anomalies and hence of male origin. Aneuploid mosaics most commonly arise by chromosome loss, followed by chromosome gain and least frequently by mitotic nondisjunction. All may be related to maternal age as well as to lack of specific gene products in the embryo. Partial aneuploidy as a result of chromosome breakage affects a minimum of 10% of embryos.
Mechanisms of nondisjunction in human spermatogenesis
Authors: Martin R.H.
Published: September 2005

A reduction in recombination in the pseudoautosomal region is associated with an increased frequency of aneuploid 24,XY human sperm. Similarly, individuals with paternally derived Klinefelter syndrome (47,XXY) also have a paucity of recombination in the chromosomes that have undergone nondisjunction. Meiotic studies using newly developed immunocytogenetic techniques have demonstrated errors of chromosome synapsis and significantly reduced recombination in infertile men with nonobstructive azoospermia. These men have an increased risk of aneuploidy in sperm that have been surgically removed from the testes. Thus, evidence is starting to accumulate that reduced recombination has a marked effect on the generation of aneuploid sperm.