bluuebunny/crossref_metadata_2025 huggingface dataset:
Geological relationships and40Ar/39Ar age constraints on gold mineralisation at Tarcoola, central Gawler gold province, South Australia
Authors: BUDD A. R. , FRASER G. L.
Published: February 2005

The Tarcoola Goldfield is one of several districts included in the recently proposed central Gawler gold province. Understanding of the genesis of the deposits in this metallogenic province is in its infancy, and dating the age of alteration, mineralisation and microdiorite dyke intrusions has been carried out at Tarcoola as a first step towards developing mineral‐systems models for the province. At Tarcoola, four samples of sericite from alteration as well as one sample of hornblende from a microdiorite dyke yield40Ar/39Ar ages ofca 1580 Ma. Geological and petrological relationships suggest that this age represents the time of fracture‐controlled Au mineralisation. These data provide evidence for coeval Au mineralisation, microdiorite dyke intrusion and local deformation. This mineralisation age is indistinguishable from U–Pb ages for the regional Gawler Range – Hiltaba volcano‐plutonic complex, and is more than 100 million years younger than the Paxton Granite, which is part‐host to the mineralisation. Possible temporal and genetic relationships with other deposits in the central Gawler gold province remain to be tested.
Late Oligocene Kangaroo Well Local Fauna from the Ulta Limestone (new name), and climate of the Miocene oscillation across central Australia
Authors: MEGIRIAN D. , MURRAY P. , SCHWARTZ L. , VON DER BORCH C.
Published: February 2005

The Late Oligocene Kangaroo Well Local Fauna from the Ulta Limestone (new name), northwestern Lake Eyre Basin correlates best with vertebrate assemblages from the Etadunna, Namba and Wipajiri Formations of the central Lake Eyre Basin, and from the Carl Creek Limestone (Karumba Basin) of northwestern Queensland. The biochronologically informative marsupials, Neohelos tirarensis (Diprotodontidae, Zygomaturinae), Marlu sp. cf. M. kutjamarpensis and Pildra sp. cf. P. magnus (Pseudocheiridae), and Ektopodon ulta sp. nov. (Ektopodontidae), indicate that the Kangaroo Well Local Fauna may be slightly older than the Kutjamarpu Local Fauna (Wipajiri Formation) and slightly younger than the Ngama Local Fauna (zone D of the Etadunna Formation) of Late Oligocene age. A new species of primitive ?Wynyardiidae, Ayekaye jaredi sp. nov., is described, and the nomenclature of two extinct gastropods, Glyptophysa rodingae (McMichael) and Cupedora lloydi (McMichael) (new combinations), the type localities of which are in the Ulta Limestone, is revised in line with current taxonomy. The Ulta Limestone, an alluvial calclithite composed primarily of caliche fabrics, and its correlatives were deposited during the Miocene oscillation climatic event. Palaeoclimatic modelling using sedimentological data, crocodilians and extant analogs of fossil terrestrial gastropods indicates that the average annual temperature at Kangaroo Well during the Late Oligocene was probably between 14 and 20°C, while mean annual rainfall was probably <600 mm. Similar associations from central parts of the Lake Eyre Basin, from Riversleigh, northwestern Queensland, and from Bullock Creek, north‐central Northern Territory, indicate that such conditions were widespread during depositional phases of the Miocene oscillation. Palaeoclimatic indicators do not support the presence of widespread closed forests in northwestern Queensland and across the inland of the Northern Territory and South Australia during the Miocene oscillation.
Geomorphology and surficial sediments of the southeast Australian continental margin
Authors: BOYD R. , RUMING K. , ROBERTS J. J.
Published: February 2005

The southeast Australian continental margin stretches 1500 km north from Bass Strait to the Great Barrier Reef. This part of the Australian margin represents a distinct oceanographic, climatic and geological province. Recent initiatives by the Australian Hydrographic Office, Geoscience Australia and the Environmental Geoscience Group at the University of Newcastle have provided a new digital database of bathymetric soundings and surface‐sediment distribution for the southeast Australian margin. This database is used here to provide the first detailed digital 3‐D representations of the southeast Australian margin, leading to new morphological classifications and integrated sedimentation models. As a result of its tectonic history of asymmetric passive margin rifting, the continental margin as a whole is narrow, steep and sediment deficient. The shelf can be divided into an inner zone with bedrock cropping out or close to the surface, and an outer zone that represents the top of a Cenozoic sediment wedge. The continental shelf and slope can be classified into a variety of morphological units based on detailed analysis of geometry and slope. These units include a succession of shore‐normal zones (shoreface, inner plain, inner and mid‐slope, outer plain and continental slope) and a number of local regions (mounds, lobes, tongues, depressions, deltas and bedrock). Sediments are generally siliciclastic in composition on the inner margin and carbonate‐rich on the outer margin, reflecting carbonate production at low sea‐levels on the outer shelf/continental slope and terrestrial sediment input to the inner shelf. Fine‐grained sediments are rare on the shelf north from Port Stephens, and occur draped across the inner and mid‐slope further south. Outer shelf carbonate sediments are coarse grained with a patchy distribution related to winnowing by the East Australian Current. The East Australian Current also produces erosional depressions and southward prograding sediment tongues and lobes where it separates from the shelf off Port Stephens. The margin character varies markedly from south to north in terms of fine‐sediment distribution, depth to the shelf break and width of the outer shelf. These outer shelf features reflect an inherited palaeotopography from underlying Cenozoic sediment wedges that are better developed on the southern margin.
Gefitinib in advanced non‐small cell lung cancer
Authors: Sharma R. , Boyer M. , Clarke S. , Millward M.
Published: February 2005

Background:  Gefitinib is an oral, selective epidermal growth factor receptor (EGFR) inhibitor that has activity in non‐small cell lung cancer (NSCLC).

Aim:  To evaluate the tolerability, safety‐profile and response of single agent gefitinib in patients with advanced stage NSCLC.

Methods:  Twenty‐seven patients of good performance status with stage IIIB or IV NSCLC were entered on the study at the Sydney Cancer Centre. Gefitinib was prescribed at an oral dose of 250 mg daily, as a continuous dose. Radiological evaluation of indicator lesions occurred at baseline and were repeated every 2–3 months until disease progression. Toxicity was graded using standard measures at baseline and at every month.

Results:  The response rate was 17% in the patients eligible for evaluation. Symptom improvement was observed in 75% of patients. No patients withdrew because of adverse events. Toxicity was observed in 15 patients and consisted mainly of rash (59%), which was usually mild in severity.

Conclusion:  Gefitinib is active in NSCLC. It is well tolerated with minimal side‐effects. Symptomatic improvement was found in the majority of patients treated with gefitinib. There may be a role for gefitinib in the palliation of symptoms in patients with advanced NSCLC. (Intern Med J 2005; 35: 77–82)
Sharing Empirical Knowledge to Improve Breastfeeding Promotion and Support: Description of a Research Dissemination Project
Authors: Loiselle Carmen G. , Semenic Sonia , Côté Brigitte
Published: February 2005

Background: Effective transfer of research findings to health care settings is a shared priority among researchers, clinicians, and decision makers. A multidisciplinary, multi‐method investigation conducted in 2001 that explored breastfeeding practices and support within a large immigrant community in Montreal, Quebec, Canada, bore numerous implications for practice. Peer‐reviewed funding was subsequently granted to support dissemination of these findings to relevant stakeholders.

Method: Key steps in implementing this research dissemination project included (1) identifying and attracting target audiences from hospitals, community health settings, and government agencies; (2) tailoring tools for communication of research findings to the various needs of audiences; (3) designing interactive workshops to facilitate knowledge uptake; and (4) integrating the project outcomes within a government‐sponsored regional breastfeeding committee for longer‐term impact.

Findings: Despite organizational challenges, more than 90 health care providers, decision makers, and breastfeeding support volunteers participated in the project workshops. Through feedback loops, the dissemination activities contributed new layers of understanding to the original research findings. The activities also engaged audience members to identify more effective breastfeeding support interventions and led to the adoption of breastfeeding support priorities shared by hospital, community, and government stakeholders.

Conclusion: This dissemination project provided unique opportunities for researchers and stakeholders to share in the interpretation of research findings and to strategically plan for future interventions to promote and support breastfeeding within ethnically diverse communities. Further research dissemination work should continue to be theoretically grounded, include systematic, long‐term assessment of dissemination outcomes, and be adequately financed throughout.
A Highly Polymorphic Poly‐Glutamine Stretch in the Potassium Channel KCNN3 in Migraine
Authors: Mössner Rainald , Weichselbaum Annette , Marziniak Martin , Freitag Christine M , Lesch Klaus‐Peter , Sommer Claudia , Meyer Jobst
Published: February 2005

Objective.—The present study is designed to further elucidate the molecular genetic basis of migraine with and without aura.

Background.—Migraine is a common disease of as yet unknown etiology. Interest in ion channels in migraine has been spurred by molecular genetic findings in familial hemiplegic migraine, since familial hemiplegic migraine type 1 is caused by mutations in the calcium channel gene CACNA1A.

Methods.—Given this role of ion channels in migraine, we assessed the potassium channel KCNN3 as a candidate gene for common migraine. We analyzed the highly polymorphic repeat region coding for a poly‐glutamine stretch, which constitutes part of the cytoplasmic tail of the channel protein.

Results.—We found an excess of the allele coding for 15 poly‐glutamines in migraine patients.

Conclusions.—The potassium channel KCNN3 may thus be of pathophysiological importance in migraine with and without aura.
Triptan Nonresponder Studies: Implications for Clinical Practice
Authors: Dodick David W.
Published: February 2005

The maximum absolute response rate with oral triptans, as measured in clinical trials by the incidence of relief from migraine pain at 2 hours after taking medication, is approximately 70%. Therefore around 30% of patients fail to respond to a particular triptan. Nonresponse is likely to be due to a variety of factors, including low and inconsistent absorption, use of the medication late in an attack, inadequate dosing, and variability in individual response. Evidence from recent clinical trials, however, confirms the common clinical observation that patients with a poor response to one triptan can benefit from subsequent treatment with a different triptan. Two‐hour pain‐relief rates of 25% to 81% using alternative triptans (naratriptan, almotriptan, eletriptan, zolmitriptan, and rizatriptan) have been reported in patients who were described as poor responders to sumatriptan. Physicians should remain vigilant in assessing the response to acute therapy and take advantage of simple clinical questionnaires that have been developed to facilitate the recognition of those patients who require and may benefit from a change in acute therapy.
Reproductive Decision‐Making Among HIV‐Positive Couples in Taiwan
Authors: Ko Nai‐Ying , Muecke Marjorie
Published: February 2005

Purpose:

To explore the gender‐based power relationships and social and cultural influences on reproductive decision‐making processes among HIV‐positive couples in Taiwan.

Methods:

The study sample consisted of 14 HIV‐positive couples in southern Taiwan. Data were analyzed using feminist ethnography to explore reproductive decisions made by these couples within the context of Taiwanese society.

Findings:

Self‐knowledge of HIV status had a limited influence on decisions about childbearing. More important was the Confucian values of filial piety and familial obligation, a powerful norm that still dictates procreation decisions in Taiwan. The process by which the couples made reproductive decisions consisted of four stages: initial reproductive decisions between partners, their search for information, their encounters with medical systems, and their weighing risks and benefits. Male and female partners expressed different concerns, and gender‐based power relationships were exercised during the decision‐making process.

Conclusions:

HIV status was not the sole determinant of reproductive decisions made by HIV‐positive couples. Rather, the Confucian value of filial piety drove the couples' reproductive decisions.
The enigma of nonholonomic constraints
Authors: Flannery M. R.
Published: February 2005

The problems associated with the modification of Hamilton’s principle to cover nonholonomic constraints by the application of the multiplier theorem of variational calculus are discussed. The reason for the problems is subtle and is discussed, together with the reason why the proper account of nonholonomic constraints is outside the scope of Hamilton’s variational principle. However, linear velocity constraints remain within the scope of D’Alembert’s principle. A careful and comprehensive analysis facilitates the resolution of the puzzling features of nonholonomic constraints.
Experimental demonstration of the physics of resonant cavities
Authors: Pellicer-Porres J. , Andrés M. V.
Published: February 2005

We describe an undergraduate experiment that demonstrates the physics of cavity resonators. A mobile wall lets students alter the position of the nodes, thus changing the mode pattern. The nodal structure is made apparent by placing a metallic plate at different positions inside the cavity. A technique for dielectric characterization also is introduced, which helps students understand the boundary conditions in dielectrics, as well as highlighting the characteristics of fields in cavities.
Treks of Imagination
Authors: Wilczek Frank
Published: February 2005

The Road to Reality
A Complete Guide to the Laws of the Universe.
By Roger Penrose
. Jonathan Cape, London, 2004. 1122 pp. £30, C$85. ISBN 0-224-04447-8. Knopf, New York, 2005. $40. ISBN 0-679-45443-8.

The author offers a comprehensive account of his perspective on our understanding of the physical behavior of the universe and the mathematical theory that underlies it.
Context-Dependent Stimulation Effects on Saccade Initiation in the Presupplementary Motor Area of the Monkey
Authors: Isoda Masaki
Published: February 2005

Although evidence suggests that the contribution of the presupplementary motor area (pre-SMA) to voluntary motor control is effector-nonselective, the question of how electrical stimulation of the pre-SMA affects eye movements remains unanswered. To address this issue, stimulus effects of the pre-SMA of monkeys on saccade initiation were investigated during performance of a visually guided saccade task with an instructed delay period. This report describes two major findings. First, when stimuli with currents of ≤80 μA were applied before the presentation of a go signal, the reaction time (RT) of an upcoming saccade shortened with comparable effects on ipsi- and contraversive saccades. Second, stimuli that were delivered after the go signal lengthened the RT; this resulted in greater effects on ipsiversive saccades. In addition, the stimulation yielded a mild impairment of saccade accuracy, particularly when the stimulation was delivered after the go signal. By themselves, however, these stimuli did not directly elicit eye movements. Therefore the stimulus effects appeared only in the context of the behavioral task and were dependent on the phase of the task. These findings provide additional support for the hypothesis that the involvement of the pre-SMA in motor control can be linked to either eye or arm motor system dependent on behavioral context.
Activation of coagulation and hyperfibrinolysis in patients with aortic arch atheromatosis (Aortic AA) as a risk factor for cerebral ischemia
Authors: Mirau Wladimir , Brueckner Sabine , Jahn Juergen , Roth-Isigkeit Angela , Gutsche Sven , Mitusch Rolf , Sheikhzadeh Abdolhamid , Siemens Hans-Joachim G.
Published: February 2005

In patients with cerebral ischemia, a frequent finding is atheromatous plaques in the ascending aorta and the aortic arch. Since we were able to demonstrate that patients with atrial fibrillation have an increased coagulatory activity, we wanted to evaluate a potential systemic activation of the coagulatory system in patients with aortic arch atheromatosis (Aortic AA). In 134 consecutive patients, we determined several parameters of the co-agulatory and fibrinolytic systems as well as several thrombophilia risk factors and compared the results with 134 age- and sex-matched healthy controls. In 90 of the 134 patients, transesophageal echocardiography showed Aortic AA, and in the remaining 44 patients, there were no aortic findings. The Aortic AA group showed higher concentrations of thrombin-antithrombin (TAT) and plasmin-antiplasmin complexes (PAP). Further division into 4 subgroups of different severity (grade I: no plaques; grade II: plaques 2–5 mm, grade III: plaques > 5 mm, grade IV: mobile plaques), revealed increasing concentrations of fibrinogen, D-dimers and tissue-type plasminogen activator. The grade IV-group displayed the highest values in comparison to all other groups. In conclusion, Aortic AA as such is a risk factor for cerebral ischemia. It causes a systemically detectable activation of coagulation which substantially exceeds the values for controls. This observation is in accordance with our findings in patients with atrial fibrillation.
The epidemiology of college alcohol and gambling policies
Authors: Shaffer Howard J , Donato Anthony N , LaBrie Richard A , Kidman Rachel C , LaPlante Debi A
Published: February 2005

Background

This article reports the first national assessment of patterns of drinking and gambling-related rulemaking on college campuses (e.g., punitive versus recovery oriented). Analyses relating school policies to known school rates of drinking or gambling identified potentially influential policies. These results can inform and encourage the development of guidelines, or "best practices," upon which schools can base future policy.

Methods

The college policy information was collected from handbooks, Web sites and supplemental materials of 119 scientifically selected colleges included in the fourth (2001) Harvard School of Public Health College Alcohol Study (CAS). A coding instrument of 40 items measured the scope and focus of school alcohol and gambling policies. This instrument included items to measure the presence of specific policies and establish whether the policies were punitive or rehabilitative. A total of 11 coders followed a process of information extraction, coding and arbitration used successfully in other published studies to codify policy information.

Results

Although all schools had a student alcohol use policy, only 26 schools (22%) had a gambling policy. Punitive and restrictive alcohol policies were most prevalent; recovery-oriented policies were present at fewer than 30% of schools. Certain alcohol and gambling policies had significant relationships with student binge drinking rates.

Conclusions

The relative lack of college recovery-oriented policies suggests that schools might be overlooking the value of rehabilitative measures in reducing addictive behaviors among students. Since there are few college gambling-related policies, schools might be missing an opportunity to inform students about the dangers of excessive gambling.
Thyroid hormone T3 acting through the thyroid hormone α receptor is necessary for implementation of erythropoiesis in the neonatal spleen environment in the mouse
Authors: Angelin-Duclos Cristina , Domenget Chantal , Kolbus Andrea , Beug Hartmut , Jurdic Pierre , Samarut Jacques
Published: February 2005

Thyroid hormones (THs) mediate many physiological and developmental functions in vertebrates. All these functions are mediated by binding of the active form of the TH T3 to the specific nuclear receptors TRα and TRβ, which are transcription factors. Using mutant mice lacking TRs or deficient for TH production, we show that T3 influences neonatal erythropoiesis through TRα. The effect of T3 and TRα is restricted to this developmental window and is specific for the spleen but not for other erythropoietic organs. We show that T3 via TRα affects late steps of erythrocytic development, promoting the proliferation of late basophilic erythroblasts. In vitro, this effect is exerted directly on erythrocytic cells. In vivo, the action of T3 is also intrinsic to spleen erythrocytic progenitors, as shown by grafting experiments of splenocytes derived from wildtype and TRα knockout (TRα0/0) mice into wild-type and TRα0/0 irradiated recipients. Our results indicate that defective spleen erythropoiesis in hypothyroid and TRα0/0mice results from impaired recognition of the spleen environment by the mutant erythrocytic progenitors. The data presented support a model in which T3 signaling through TRα is essential for the implementation of the transient spleen erythropoiesis at birth.
The primitive streak geneMixl1is required for efficient haematopoiesis and BMP4-induced ventral mesoderm patterning in differentiating ES cells
Authors: Ng Elizabeth S. , Azzola Lisa , Sourris Koula , Robb Lorraine , Stanley Edouard G. , Elefanty Andrew G.
Published: February 2005

The homeobox gene Mixl1 is expressed in the primitive streak of the gastrulating embryo, and marks cells destined to form mesoderm and endoderm. The role of Mixl1 in development of haematopoietic mesoderm was investigated by analysing the differentiation of ES cells in which GFP was targeted to one (Mixl1GFP/w) or both(Mixl1GFP/GFP) alleles of the Mixl1 locus. In either case, GFP was transiently expressed, with over 80% of cells in day 4 embryoid bodies (EBs) being GFP+. Up to 45% of Mixl1GFP/w day 4 EB cells co-expressed GFP and the haemangioblast marker FLK1, and this doubly-positive population was enriched for blast colony forming cells (BL-CFCs). Mixl1-null ES cells,however, displayed a haematopoietic defect characterised by reduced and delayed Flk1 expression and a decrease in the frequency of haematopoietic CFCs. These data indicated that Mixl1 was required for efficient differentiation of cells from the primitive streak stage to blood. Differentiation of ES cells under serum-free conditions demonstrated that induction of Mixl1- and Flk1-expressing haematopoietic mesoderm required medium supplemented with BMP4 or activin A. In conclusion,this study has revealed an important role for Mixl1 in haematopoietic development and demonstrates the utility of the Mixl1GFP/wES cells for evaluating growth factors influencing mesendodermal differentiation.
Peripheral nerve-derived VEGF promotes arterial differentiation via neuropilin 1-mediated positive feedback
Authors: Mukouyama Yoh-suke , Gerber Hans-Peter , Ferrara Napoleone , Gu Chenghua , Anderson David J.
Published: February 2005

In developing limb skin, peripheral nerves are required for arterial differentiation, and guide the pattern of arterial branching. In vitro experiments suggest that nerve-derived VEGF may be important for arteriogenesis, but its role in vivo remains unclear. Using a series of nerve-specific Cre lines, we show that VEGF derived from sensory neurons,motoneurons and/or Schwann cells is required for arteriogenesis in vivo. Arteriogenesis also requires endothelial expression of NRP1, an artery-specific coreceptor for VEGF164 that is itself induced by VEGF. Our results provide the first evidence that VEGF is necessary for arteriogenesis from a primitive capillary plexus in vivo, and show that in limb skin the nerve is indeed the principal source of this signal. They also suggest a model in which a `winner-takes-all' competition for VEGF may control arterial differentiation, with the outcome biased by a VEGF164-NRP1 positive-feedback loop. Our results also demonstrate that nerve-vessel alignment is a necessary, but not sufficient, condition for nerve-induced arteriogenesis. Different mechanisms therefore probably underlie these endothelial patterning and differentiation processes.
Reelin signaling is necessary for a specific step in the migration of hindbrain efferent neurons
Authors: Rossel Mireille , Loulier Karine , Feuillet Christian , Alonso Serge , Carroll Patrick
Published: February 2005

The cytoarchitecture of the hindbrain results from precise and co-ordinated sequences of neuronal migrations. Here, we show that reelin, an extracellular matrix protein involved in neuronal migration during CNS development, is necessary for an early, specific step in the migration of several hindbrain nuclei. We identified two cell populations not previously known to be affected in reeler mutants that show a common migratory defect: the olivocochlear efferent neurons and the facial visceral motor nucleus. In control embryos, these cells migrate first toward a lateral position within the neural tube, and then parallel to the glial cell processes, to a ventral position where they settle close to the pial surface. In reelermutants, the first migration is not affected, but the neurons are unable to reach the pial surface and remain in an ectopic position. Indeed, this is the first evidence that the migration of specific hindbrain nuclei can be divided into two parts: a reelin-independent and a reelin-dependent migration. We also show that reelin is expressed at high levels at the final destination of the migratory process, while the reelin intracellular effector Dab1 was expressed by cell groups that included the two populations affected. Mice mutant at the Dab1 locus, called scrambler, exhibit the same phenotype, a failure of final migration. However, examination of mice lacking both reelin receptors, ApoER2 and VLDLR, did not reveal the same phenotype, suggesting involvement of an additional reelin-binding receptor. In the hindbrain, reelin signaling might alter the adhesive properties of efferent neurons and their ability to respond to directional cues, as has been suggested for the migration of olfactory bulb precursors.
New insights into craniofacial morphogenesis
Authors: Helms Jill A. , Cordero Dwight , Tapadia Minal D.
Published: February 2005

No region of our anatomy more powerfully conveys our emotions nor elicits more profound reactions when disease or genetic disorders disfigure it than the face. Recent progress has been made towards defining the tissue interactions and molecular mechanisms that control craniofacial morphogenesis. Some insights have come from genetic manipulations and others from tissue recombinations and biochemical approaches, which have revealed the molecular underpinnings of facial morphogenesis. Changes in craniofacial architecture also lie at the heart of evolutionary adaptation, as new studies in fish and fowl attest. Together, these findings reveal much about molecular and tissue interactions behind craniofacial development.
Constructing Price Indexes across Space and Time: The Case of the European Union
Authors: Hill Robert J
Published: February 2005

This paper considers the problem of how to construct and reconcile price indexes across space and time. A general taxonomy of panel price index methods, containing four broad classes, is proposed, along with five criteria for discriminating between them. Methods from each of the four classes are then used to compute spatial and temporal price indexes for the 15 countries of the European Union (EU) over the period 1995–2000. Using these panel price indexes, I test whether or not price levels and relative prices converged across the EU over this period.
Riding the South Sea Bubble
Authors: Temin Peter , Voth Hans-Joachim
Published: February 2005

This paper presents a case study of a well-informed investor in the South Sea bubble. We argue that Hoare's Bank, a fledgling West End London bank, knew that a bubble was in progress and nonetheless invested in the stock: it was profitable to “ride the bubble.” Using a unique dataset on daily trades, we show that this sophisticated investor was not constrained by such institutional factors as restrictions on short sales or agency problems. Instead, this study demonstrates that predictable investor sentiment can prevent attacks on a bubble; rational investors may attack only when some coordinating event promotes joint action.
Decay of mRNAs targeted by RISC requires XRN1, the Ski complex, and the exosome
Authors: ORBAN TAMAS I. , IZAURRALDE ELISA
Published: February 2005

RNA interference (RNAi) is a conserved RNA silencing pathway that leads to sequence-specific mRNA decay in response to the presence of double-stranded RNA (dsRNA). Long dsRNA molecules are first processed by Dicer into 21–22-nucleotide small interfering RNAs (siRNAs). The siRNAs are incorporated into a multimeric RNA-induced silencing complex (RISC) that cleaves mRNAs at a site determined by complementarity with the siRNAs. Following this initial endonucleolytic cleavage, the mRNA is degraded by a mechanism that is not completely understood. We investigated the decay pathway of mRNAs targeted by RISC inDrosophilacells. We show that 5′ mRNA fragments generated by RISC cleavage are rapidly degraded from their 3′ ends by the exosome, whereas the 3′ fragments are degraded from their 5′ ends by XRN1. Exosome-mediated decay of the 5′ fragments requires theDrosophilahomologs of yeast Ski2p, Ski3p, and Ski8p, suggesting that their role as regulators of exosome activity is conserved. Our findings indicate that mRNAs targeted by siRNAs are degraded from the ends generated by RISC cleavage, without undergoing decapping or deadenylation.
An Improved Method for Determination of the Cavitation Erosion Resistance by a Weibull Distribution
Authors: Meged Y
Published: February 2005

The improved method for determination of cavitation erosion resistance is based on the erosion strength concept and the Weibull cumulative distribution function. Cavitation erosion resistance is the ratio between the erosion intensity, which is the external load, and the erosion rate, which is the response of the eroded material. The time at which this erosion rate is determined is t200, i.e., when the average eroded thickness reaches 200 µm. This time ensures that the cavitation erosion resistance of both the boundary layer and the base material can be determined. The improved method is simple, easy to apply, and overcomes the drawbacks of the normalized erosion method and the erosion strength method. In this case, cavitation erosion resistance is an independent, measurable value with units of stress.
A New Test Method and Pictorial Markings for Packages Containing Liquid Dangerous Goods in High Altitude Shipments
Authors: Singh SP , Burgess GJ , Singh J
Published: February 2005

Serious accidents have occurred over the past decade as a result of package failures during high altitude shipments on aircraft. Dangerous goods require sturdier packages since their contents can result in life-threatening incidents if exposed to the environment. High altitude shipments are encountered when trucks travel over mountain passes or when cargo and feeder aircraft transport packages in non-pressurized or partially-pressurized cargo holds. Both types of transport methods result in severe drops in pressure compared to packages transported close to sea level. The testing of packages under these conditions is critical since package integrity must be improved. Current shipping tests performed in test labs do not account for pressure changes and vibration together. This paper proposes a new test method to simulate package conditions in high altitude shipments by subjecting the package to simultaneous vibration and low pressure. It also recommends pictorial markings be used on packages to show whether or not they meet the air and ground shipping requirements.
Detailed clinical description of four patients with 1.3 and 2.1 Mb chromosome imbalances derived from a familial t(12;17)(q24.33;q25.3)
Authors: Schoumans Jacqueline , Sanner Gunnar , Nordenskjöld Magnus , Anderlid Britt‐Marie
Published: February 2005

We describe a family carrying a submicroscopic reciprocal translocation involving 12qter and 17qter detected by subtelomeric FISH analysis. Four family members inherited unbalanced variants‐two cases inherited the derivative chromosome 12 and the other two the derivative chromosome 17. The two individuals with the derivative chromosome 17 showed a distinct phenotype with mild mental retardation in combination with multiple minor malformations, while the phenotype in the cases with the derivative chromosome 12 was milder and only partly concordant. Detailed FISH analysis using 19 BAC clones covering the distal part of chromosome 12q and 17q estimated the imbalances to 2.1 and 1.3 Mb, respectively. The clinical and cytogenetic findings of the two different genotypes are reported and discussed. This family illustrates that small chromosome imbalances can be detected in individuals with mild phenotype and normal, or near‐normal, cognitive functions. © 2005 Wiley‐Liss, Inc.
Soluble novel optically active poly(amide–imide)s derived from N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐leucine diacid chloride and various aromatic diamines: Synthesis and characterization
Authors: Mallakpour Shadpour , Kowsari Elaheh
Published: February 2005

4,4′‐Oxydiphthalic anhydride (1) was reacted with L‐leucine (2) in acetic acid, and the resulting imide‐acid (3) was obtained in high yield. The diacid chloride (4) was obtained from diacid derivative (3) by reaction with thionyl chloride. The polycondensation reaction of diacid chloride (4) with several aromatic diamines, such as 4,4′‐sulfonyldianiline (5a), 4,4′‐diaminodiphenyl methane (5b), 4,4′‐diaminodiphenylether (5c), p‐phenylenediamine (5d), m‐phenylenediamine (5e), and 4,4′‐diaminobiphenyl (5f), was performed by two conventional methods: low temperature solution polycondensation and short period reflux conditions. To compare conventional solution polycondensation reaction methods with microwave‐assisted polycondensation, the reactions were also carried out under microwave conditions in the presence of a small amount of o‐cresol that acts as a primary microwave absorber. The reaction mixture was irradiated for 6 min with 100% of radiation power. Several new optically active poly(amide–imide)s with inherent viscosity ranging from 0.25–0.52 dL/g were obtained with high yield. All of the above polymers were fully characterized by IR, elemental analyses, and specific rotation techniques. Some structural characterizations and physical properties of these new optically active poly(amide–imide)s are reported. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 435–442, 2005
Effect of carbon black on properties of rubber nanocomposites
Authors: Maiti Madhuchhanda , Sadhu Susmita , Bhowmick Anil K.
Published: February 2005

Polymer based nanocomposites were prepared using brominated poly(isobutylene‐co‐paramethylstyrene) (BIMS) rubber and octadecyl amine modified montmorillonite nanoclay. The effect of nature and loading of carbon black on these nanocomposites and the control BIMS was investigated thoroughly using X‐ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and mechanical properties. The addition of 4 parts of the modified nanoclay to 20 phr N550 carbon black filled samples increased the tensile strength by 53%. Out of the three different grades of carbon black (N330, N550, and N660), N550 showed the best effect of nanoclay. Optimum results were obtained with the 20 phr filler loading. For comparison, china clay and silica at the same loading were used. Fifty‐six and 46% improvements in tensile strength were achieved with 4 parts of nanoclay added to the silica and the china clay filled samples, respectively. N330 carbon black (20 parts) filled styrene butadiene rubber (SBR) based nanocomposite registered 20% higher tensile strength with 4 parts of the modified nanoclay. In all the above carbon black filled nanocomposites, the modulus was improved in the range of 30 to 125%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 443–451, 2005
Synchrotron radiation circular dichroism spectroscopy applied to metmyoglobin and a 4‐α‐helix bundle carboprotein
Authors: Thulstrup Peter W. , Brask Jesper , Jensen Knud J. , Larsen Erik
Published: February 2005

The novel technique, synchrotron radiation‐based circular dichroism (SR‐CD), has been applied to the study of metmyoglobin and a carboprotein (carbohydrate‐based peptide with protein tertiary structure) with 4‐α‐helix bundle structure, as well as a carbopeptide (carbohydrate‐based peptide) with a truncated peptide sequence. The use of synchroton radiation (SR) enabled circular dichroism (CD) measurements in the vacuum ultraviolet (VUV) down to 168 nm in D2O and 160 nm in 2,2,2‐trifluoroethanol (TFE). The band shape in the CD spectra in the low wavelength region was studied, comparing samples with two types of α‐helical tertiary structure, namely the globin fold and the 4‐α‐helix bundle motif. No significant differences were found between the CD spectra of the α‐helical samples (metmyoglobin and carboprotein) in D2O solution. The use of 2,2,2‐TFE (TFE) as solvent clearly alters the VUV CD but the two samples have very similar CD spectra. The solvent‐induced denaturing of metmyoglobin in TFE was observed using absorption and CD spectroscopy of the Soret band, with results indicating heme release. The VUV spectrum of TFE‐denatured metmyoglobin exhibits dramatic differences in comparison with previous studies of the native enzyme in aqueous solution. The implications of this observation are discussed. © 2005 Wiley Periodicals, Inc. Biopolymers 78: 46–52, 2005
Synthesis, Structure and Photoreactivity of Several Cinnamophane Vinylogs
Authors: Greiving Helmut , Hopf Henning , Jones Peter G. , Bubenitschek Peter , Desvergne Jean‐Pierre , Bouas‐Laurent Henri
Published: February 2005

In preceding papers, cinnamophanes 1a–d (two cinnamic ester units locked in a [2.2]paracyclophane skeleton) were described. In particular, the pseudo‐gem isomer 1a was shown to produce in solution an intramolecular cyclobutane photocycloadduct with stereospecificity and very high efficiency, following the topochemical rule observed in the solid state. Here are reported the synthesis and X‐ray structure determination of their vinylogs 5a–d. The photoreactivity of the pseudo‐gem isomer 5a was especially investigated in order to examine whether the same specificity would be maintained for the longer dienic substituents. It was found that, depending on the irradiation wavelengths, different bicyclic (8) and tetracyclic (9 and 10) intramolecular photocycloadducts (ladderanes) were produced, but with reduced efficiency as compared to that of 1a. The pseudo‐ortho‐ and pseudo‐para isomers 5b and 5d form the oxetenes 11 and 12, respectively, on irradiation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis of Spirocyclopropanated Analogues of Imidacloprid and Thiacloprid
Authors: Brackmann Farina , Yufit Dmitrii S. , Howard Judith A. K. , Es‐Sayed Mazen , de Meijere Armin
Published: February 2005

tert‐Butyl N‐[1‐(hydroxymethyl)cyclopropyl]carbamate (8) was converted into spirocyclopropanated analogues 14‐CP and 14‐CT of the insecticide Thiacloprid (2) in six simple steps with overall yields of 24 % each, along with their regioisomers 13‐CP and 13‐CT in overall yields of 17 and 15 %, respectively. The spirocyclopropanated analogues 27‐CP and 27‐CT of the insecticide Imidacloprid (1) were prepared from 8 in five steps in an overall yield of 10 % each, along with their regioisomers 20‐CP and 20‐CT in an overall yield of 8 and 7 %, respectively. The key step in all preparations was a cocyclization of an appropiately protected (1‐aminocyclopropyl)methyl derivative with S,S‐dimethyl cyanodithioiminocarbonate (11) or nitroguanidine (22). The structures of several final products and by‐products were verified by X‐ray crystal structure analyses.
Facile Construction of Spirocyclopropanated Bi‐, Tri‐ and Tetracyclic Skeletons by Novel Cascades Involving Intra‐ and Intermolecular Heck Reactions of 2‐Bromo‐1,6‐enynes and Bicyclopropylidene
Authors: Schelper Michael , de Meijere Armin
Published: February 2005

Acyclic 2‐bromo‐1,6‐enynes 5‐R, 9‐R and 11‐R with bulky substituents at the acetylenic terminus were co‐cyclized with the highly strained bicyclopropylidene (12) under palladium catalysis at 80 °C to give the cross‐conjugated tetraenes 13‐R, 18‐R and 19‐R in moderate‐to‐good yields (34−71%). Only the co‐cyclization of 5‐Ph gave rise to an additional product, which was identified as the 11‐membered ring 20. At elevated temperatures (120−140 °C) the initially formed tetraenes underwent 6π‐electrocyclization to give spiro[cyclopropane‐1,4′‐bicylo[4.3.0]‐1(6),2‐dienes] 21‐R, 22‐R and 23‐R. This novel class of spirocyclopropanated oligocycles is also accessible by a one‐pot protocol. The highest yields for both the tetraenes and bicyclo[4.3.0]nonadiene and its heteroanalogues were obtained with bulky substituents at the alkyne terminus of the precursors. Heteroatom‐containing precursors 9‐R and 11‐R gave lower yields than their all‐carbon analogues 5‐R. The acyclic 2‐bromo‐1,8‐dien‐6‐ynes 28a,b,c upon palladium‐catalyzed co‐cyclization with bicyclopropylidene (12) at 110 °C gave spirocyclopropanated tricycles 31a,b and 32, respectively, in moderate yields (14, 31 and 32%). These products were formed by two consecutive 6π‐electrocyclizations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Conjugated Additions of Selenium Containing Enolates to Enones – Enantioselective Synthesis of δ‐Oxo‐α‐Seleno Esters and Their Facile Transformations
Authors: Tiecco Marcello , Testaferri Lorenzo , Marini Francesca , Sternativo Silvia , Santi Claudio , Bagnoli Luana , Temperini Andrea
Published: February 2005

Titanium enolates derived from methyl phenylselenoacetate and other acetates bearing a selenium containing chiral auxiliary have been employed to bring about 1,4‐addition reactions to enones. These reactions generate δ‐oxo‐α‐seleno esters in good yields and with excellent regio‐ and diastereoselectivities. The results obtained clearly indicate that the Lewis acids, employed to activate the starting enones towards addition, greatly influence reactivity as well as the stereochemical outcomes of these reactions. TiCl4 complexation resulted in particularly efficient promotion of the 1,4‐addition. Simple manipulations of the organoselenium moiety allowed some enantiomerically pure δ‐oxo‐α‐camphorseleno esters to be transformed into the corresponding δ‐oxo‐α‐hydroxy or δ‐oxo‐α‐allyl esters or into trisubstituted tetrahydrofurans. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Stereoselective Enzymatic Synthesis of cis‐Pellitorine, a Taste Active Alkamide Naturally Occurring in Tarragon
Authors: Ley Jakob P. , Hilmer Jens‐Michael , Weber Berthold , Krammer Gerhard , Gatfield Ian L. , Bertram Heinz‐Jürgen
Published: February 2005

The stereochemical descriptor in the compound name of 1a in the first sentence of the Introduction on p. 5135 of the original article[1] is incorrect; the correct name is:

(2E,4Z)‐N‐isobutyldeca‐2,4‐dienamide
Cyclic AMP induces morphological changes of vascular smooth muscle cells by inhibiting a rac‐dependent signaling pathway
Authors: Pelletier Stéphane , Julien Catherine , Popoff Michel R. , Lamarche‐Vane Nathalie , Meloche Sylvain
Published: February 2005

Cyclic AMP (cAMP) is a pleiotropic second messenger that regulates numerous cellular processes. In vascular smooth muscle cells (VSMCs), these include cell proliferation, migration, and contractility. Here we show that cAMP‐elevating agents induce dramatic morphological changes in VSMCs, characterized by cell rounding and formation of long branching processes. The stellate morphology is associated with disassembly of actin stress fibers and lamellipodia, loss of focal adhesions, and the formation of small F‐actin rings. Because of the importance of Rho family GTPases in regulating actin dynamics, we analyzed their individual roles in the cAMP phenotype. We found that pharmacological or genetic inhibition of Rac mimics cAMP effect in inducing a stellate morphology of VSMCs. Expression of activated Rac1 prevents forskolin‐induced cAMP stellation, suggesting that cAMP affects cell morphology by inhibiting Rac function. Consistent with this, treatment with forskolin inhibits agonist‐stimulated Rac activation in VSMCs. We further show that activated Rac1 containing the F37A effector loop substitution fails to rescue the cAMP phenotype. Our results suggest that cAMP modulates the morphology of VSMCs by inhibiting a Rac‐dependent signaling pathway. © 2005 Wiley‐Liss, Inc.
One‐step production of CO‐ and CO2‐free hydrogen from biomass
Authors: Ishida Minoru , Otsuka Kiyoshi , Takenaka Sakae , Yamanaka Ichiro
Published: February 2005

The reaction between a biomass (cellulose, sucrose, glucose, starch, cotton, or Japanese paper) and NaOH in the presence of water vapor produced pure hydrogen without CO and CO2 at temperatures in the range 473–623K. The addition of Ni/Al2O3 or Rh/Al2O3 catalyst to cellulose enhanced the production of hydrogen at <573 K. The reaction between cellulose and NaOH can be written as: C6H10O5 + 12NaOH + H2O = 6Na2CO3 + 12H2. The reactivities of alkali metal hydroxides were: KOH > NaOH ≫ LiOH. Copyright © 2004 Society of Chemical Industry
Analysis of the kinetics of growth and lactic acid production for Lactobacillus helveticus growing on supplemented whey permeate
Authors: Amrane Abdeltif
Published: February 2005

Growth of Lactobacillus helveticus on supplemented whey permeate was divided into five phases: lag, exponential, deceleration, stationary and decline phases. Each phase was characterized by simple model kinetics. From this and by considering a partial association of lactic acid production with growth, with an additional term introduced to account for cessation of production when the carbon substrate became limiting, the lactic acid production was analytically deduced for each growth phase. For both growth and production data, on the whole culture, the calculated values were found to match experimental data. All the model parameters can be easily deduced from experimental data. The model allows therefore a fine analysis of growth and production kinetics. Copyright © 2005 Society of Chemical Industry