bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of the skin multiple analyte profile bioanalytical method for determination of skin biomarkers from D‐Squame® tape samples
Authors: Hendrix S. W. , Miller K. H. , Youket T. E. , Adam R. , O'Connor R. J. , Morel J. G. , Tepper B. E.
Published: March 2007

Background/purpose: This work was performed to optimize extraction conditions for D‐Squame® tape skin samples for use in the skin multiple analyte profile (SkinMAP) method, a Linco Research Corporation bead‐based assay for skin analytes. The experiments were designed to help identify sources of variability during extraction that may be amenable to further control.

Methods: Two experimental designs were used to study factors influencing the extraction of skin samples from D‐Squame® tapes. Visually healthy skin samples were obtained from both female and male adult volar forearms. Factors studied in two experiments included: four surfactant (SDS) levels (0.02–0.2%), two buffer types [Citrate‐phosphate buffered saline at pH 5.5, phosphate‐buffered saline (PBS) at pH 7.4], two buffer volumes (1.0, 1.5 mL), two propylene glycol (PG) levels (0.1%, 1.0%), two extraction temperatures (7–10°C, 22–30+°C), two extraction times (30, 60 min), and location in sonication bath (two vectors). The response biomarkers were cortisol, fibronectin, human serum albumin, involucrin, keratin‐6 and keratins 1, 10. Skin sampling sites were also evaluated as sources of variation.

Results: There was no single set of extraction conditions in our experiments that maximized recovery of all the biomarkers. SDS level had the most consistently significant (P<0.05) and directional effects on biomarker recoveries. In general, higher SDS resulted in higher recovery of all biomarkers. There was less consistency and fewer significant results for the other extraction factors.

Conclusions: These data enable us to better manage SkinMAP studies and interpret their results. The use of 1.5 mL PBS containing 0.2% SDS and 0.5% PG with 30 min sonication at low (near 4°C) temperature is optimal for the quantitation of a range of SkinMAP analytes. In order to protect researchers from obtaining inflated false positive rates, it is crucial to design such studies and analyze the data using appropriate statistical methodology, especially for those studies involving only a small number of subjects.
The unique pharmacology of the scorpion α‐like toxin Lqh3 is associated with its flexible C‐tail
Authors: Karbat Izhar , Kahn Roy , Cohen Lior , Ilan Nitza , Gilles Nicolas , Corzo Gerardo , Froy Oren , Gur Maya , Albrecht Gudrun , Heinemann Stefan H. , Gordon Dalia , Gurevitz Michael
Published: March 2007

The affinity of scorpion α‐toxins for various voltage‐gated sodium channels (Navs) differs considerably despite similar structures and activities. It has been proposed that key bioactive residues of the five‐residue‐turn (residues 8–12) and the C‐tail form the NC domain, whose topology is dictated by a cis or trans peptide‐bond conformation between residues 9 and 10, which correlates with the potency on insect or mammalian Navs. We examined this hypothesis using Lqh3, an α‐like toxin from Leiurus quinquestriatus hebraeus that is highly active in insects and mammalian brain. Lqh3 exhibits slower association kinetics to Navs compared with other α‐toxins and its binding to insect Navs is pH‐dependent. Mutagenesis of Lqh3 revealed a bi‐partite bioactive surface, composed of the Core and NC domains, as found in other α‐toxins. Yet, substitutions at the five‐residue turn and stabilization of the 9–10 bond in the cis conformation did not affect the activity. However, substitution of hydrogen‐bond donors/acceptors at the NC domain reduced the pH‐dependency of toxin binding, while retaining its high potency at Drosophila Navs expressed in Xenopus oocytes. Based on these results and the conformational flexibility and rearrangement of intramolecular hydrogen‐bonds at the NC domain, evident from the known solution structure, we suggest that acidic pH or specific mutations at the NC domain favor toxin conformations with high affinity for the receptor by stabilizing the bound toxin‐receptor complex. Moreover, the C‐tail flexibility may account for the slower association rates and suggests a novel mechanism of dynamic conformer selection during toxin binding, enabling α‐like toxins to affect a broad range of Navs.
The ‘Good Enough’ Approach to Language Comprehension
Authors: Ferreira Fernanda , Patson Nikole D.
Published: March 2007

Ferreira and colleagues argued that the language comprehension system creates syntactic and semantic representations that are merely ‘good enough’ (GE) given the task that the comprehender needs to perform. GE representations contrast with ones that are detailed, complete, and accurate with respect to the input. In this article, we review the original argument for GE processing, and we present new evidence that supports the concept: first, local interpretations are computed, which can interfere with global ones; second, new findings based on the recording of event‐related potentials show the use of simple heuristics rather than compositional algorithms for constructing sentence meaning; and recent studies show that the comprehension system has mechanisms for handling disfluencies, but they work imperfectly. We argue that the GE approach to language comprehension is similar to the use of fast and frugal heuristics for decision‐making, and that future research should explore this connection more thoroughly.
Jusa and Barsuchi Log Volcanogenic Massive Sulfide Deposits from the Southern Urals of Russia: Tectonic Setting, Structure and Mode of Formation
Authors: Glasby Geoffrey P. , Prozherova Irina A. , Maslennikov Valery V. , Petukhov Sergey I.
Published: March 2007

The Jusa and Barsuchi Log volcanogenic massive sulfide (VMS) deposits formed along a paleo island arc in the east Magnitogrosk zone of the Southern Urals between ca 398 and 390 Ma. By analogy with the VMS deposits of the west Magnitogrosk zone, they are considered to be Baimak type deposits, which are Zn‐Cu‐Ba deposits containing Au, Ag and minor Pb. Detailed mapping and textural analysis of the two deposits shows that they formed as submarine hydrothermal mounds which were subsequently destroyed on the sea floor under the influence of ocean bottom currents and slumping. Both deposits display a ratio of the length to the maximum width of the deposit >15 and are characterized by ribbon‐like layers composed mainly of bedded ore and consisting principally of altered fine clastic ore facies. The Jusa deposit appears to have formed in two stages: deposition of colloform pyrite followed by deposition of copper–zinc–lead sulfides characterized by the close association of pyrite, chalcopyrite, sphalerite, galena, tennantite, arsenopyrite, marcasite, pyrrhotite, bornite, native gold and electrum and high concentrations of gold and silver. The low metamorphic grade of the east Magnitogorsk zone accounts for the exceptional degree of preservation of these deposits.
Characteristics of the Bumo Gold Field, Hainan Island, China and Gold Exploration Through Soil Geochemical Surveys
Authors: Zhou Jun , Han Ping , Liu Lei , Tian Qin‐hu , Li De‐cheng
Published: March 2007

The Bumo gold deposit is a low‐sulfide quartz vein type deposit, situated in the west of Hainan Island, approximately 25 km southeast of Dongfang City (termed Basuo in alias). Tectonically, the SW‐NE‐oriented Gezhen Ductile‐Shearing Zone was largely attenuated in Bumo. It is hosted by gneisses and schists of Proterozoic age (locally called the Baoban Group), but the radiometric age of ores mainly is Jurassic–Cretaceous, being coeval to the regional metallogenesis along the Eurasian margin. The affinity with the Phanerozoic orogenic gold deposits is indicated by low salinity (2.4 wt% NaCl–10.3 wt% NaCl), intermediate temperature (150–300°C) and appropriate δ18O value (approximately 7–11‰). The gold metal tonnage, proved previously, within an area smaller than 1.0 km2 in the gold belt II amounted to 11.59 t, with the average gold grades for the major Au quartz veins (7 and 8) in this belt of 52.7 and 71.1 g/t, respectively. This shows significant enrichment of gold and an unusual “nugget effect”. A ring structure, mainly represented by ridges, valleys, dikes, big bull quartz veins and lithological borders or pertinent faults, marks the gold field, and its origin was linked to a possible magmatic diapir. It was viewed as macroscopic evidence that the dip angles of strata tend to decline gradually from deeper ones in the center area to nearly horizontal in the outskirts, and certain intrusion‐affiliated elements such as Bi, As and W are considerably abundant in soil samples. Two areas, namely the area A (3.06 km2) in the outskirts of the ring structure or in northeastern Bumo and the area B (1.32 km2) in the field center or to the west of the gold belts I and II, were selected for the geochemical survey in a 50 × 50‐m sampling grid. The analytical results of the samples from horizon C and in a −80 mesh size showed that the average contents of Bi, As and W amounted to 0.55, 19.3 and 3.67 ppm in the area A (1225 samples) and to 0.79, 68.3 and 4.14 ppm in the area B (529 samples), respectively. This geochemical exploration led to the discovery of several Au quartz veins in both areas A and B, which also manifested an Au nugget effect (the average Au grades between 50 and 100 g/t) in spite of their limited scales (from a couple of centimeters to 50 cm wide and from several meters to 15 m long). A mylonite zone in area A was also found by this study. An intimate spatial correlation between a lithological border (gneiss and schist or pegmatite) or the mylonite zone and Au anomalies indicates an important prospect for further gold exploration.
Dating of the Giant Huize Zn‐Pb Ore Field of Yunnan Province, Southwest China: Constraints from the Sm‐Nd System in Hydrothermal Calcite
Authors: Li Wenbo , Huang Zhilong , Yin Mudan
Published: March 2007

The Huize ore field, which is the most famous high‐grade Mississippi Valley‐type Zn‐Pb ore field in China, consists of the Kuangshanchang and Qilinchang deposits. The Sm‐Nd isotopic compositions of gangue calcite were analyzed to constrain the timing of mineralization. Eight calcite samples from the No. 6 orebody in the Qilinchang deposit have Sm and Nd concentrations of 1.82–25.93 and 15.25–79.02 ppm, respectively, and yielded an age of 225 ± 9.9 Ma with epsilon Nd =−10.6 and MSWD = 0.13. Five calcites from the No. 1 orebody in the Kuangshanchang deposit contain 2.37–2.90 ppm Sm and 8.18–16.85 ppm Nd, and yielded an age of 228 ± 16 Ma, with epsilon Nd =−10.6 and MSWD = 0.28. These two ages are close to the age of the Emeishan flood basalt, which is ca 255 Ma, and agree with the reported40Ar/39Ar plateau and isochron ages of the native copper mineralization related to the Emeishan flood basalt in this region, which are 226–228 Ma. Moreover, previous study shows that the magnitude of uplift resulting from the Emeishan flood basalts is >1000 m. It indicates that the Kuangshanchang and the Qilinchang deposit formed during the same geological event and originated by fluid migration during uplift resulting from the Emeishan flood basalt.
The impact of murine strain and sex on postnatal development after maternal dietary restriction during pregnancy
Authors: Knight Brian S. , Pennell Craig E. , Adamson S. Lee , Lye Stephen J.
Published: March 2007

The objective of this study was to characterize offspring responses to maternal dietary restriction (DR) in two phylogenetically distant strains of mice: A/J and C57BL/6J (B6). Pregnant mice were fed 100% or 70% of ad libitum between 6.5 and 17.5 days (d) gestation. Offspring were fed 100%ad libitum postweaning. All comparisons were made to strain and sex matched controls. Male DR‐B6 offspring initially grew slower than controls; however, by 77d and 182d they were significantly heavier (P < 0.05). Further, they had an increase percentage fat mass (+70%, P < 0.01) by 182d and were glucose intolerant at both 80d (P < 0.001) and 186d (P < 0.05). In contrast, weight, %Fat mass and glucose tolerance in DR‐A/J males during postnatal life were not different from controls. Female DR‐B6 mice showed catch‐up growth during the first 77d of life; however, their weight, %Fat mass and glucose tolerance were not different from controls at 80d and 186d. Although female DR‐A/J were heavier than controls at 182d (P < 0.05), their %Fat mass and glucose tolerance were not different from controls at 182d and 186d. The observed strain and sex differences offer a unique opportunity to begin to define gene–environment interactions that contribute to developmental origins of health and disease.
Up‐regulation of arginase activity contributes to attenuated reflex cutaneous vasodilatation in hypertensive humans
Authors: Holowatz Lacy A. , Kenney W. Larry
Published: March 2007

Reflex cutaneous vasodilatation is dependent on nitric oxide (NO), which is diminished in hypertension (HTN). Arginase may be up‐regulated with HTN, which preferentially metabolizes l‐arginine (l‐arg), competing with NO‐synthase (NOS)‐mediated pathways and limiting NO synthesis. We hypothesized that NO‐dependent vasodilatation would be attenuated in HTN skin, and arginase inhibition (A‐I) alone or with concurrent l‐arginine supplementation, would augment vasodilatation. Five microdialysis fibres were placed in skin of eight unmedicated subjects with HTN (mean arterial pressure (MAP), 112 ± 1 mmHg) and nine age‐matched normotensive (AMN) (MAP: 87 ± 1 mmHg) men and women to serve as: control (C, Ringer solution), NOS inhibited (NOS‐I, 10 mm l‐NAME), A‐I (5 mm BEC + 5 mm nor‐NOHA), l‐arg supplemented (l‐arg, 10 mm l‐arg), and combined A‐I +l‐arg. Reflex vasodilatation was induced by using a water‐perfused suit to increase oral temperature (Tor) 1.0°C. Red cell flux was measured by laser‐Doppler flowmetry over each site. Cutaneous vascular conductance was calculated (CVC = flux/MAP) and normalized to maximal CVC (28 mm SNP + local heating to 43°C). The Δ%CVCmax between the control and NOS‐I site was calculated as the difference between C and NOS‐I sites. Maximal CVC was attenuated in the HTN subjects by ∼25% compared with AMN subjects (P < 0.001). Throughout, whole body heating %CVCmax was not different between the groups (HTN, 43 ± 3%CVCmaxversus AMN, 45 ± 3%CVCmax, P > 0.05). NOS‐I significantly decreased %CVCmax in both groups but %CVCmax was greater in the HTN group (HTN, 32 ± 4%CVCmaxversus AMN, 23 ± 3%CVCmax, P < 0.05). The Δ%CVCmax between the control and NOS‐I sites was attenuated at ΔTor > 0.5°C in the HTN group (P < 0.001 versus AMN). A‐I alone augmented %CVCmax only in the HTN group (HTN, 65 ± 5%CVCmaxversus AMN, 48 ± 3%CVCmax, P < 0.05). l‐Arg alone did not affect %CVCmax in either group (HTN, 49 ± 5%CVCmaxversus AMN, 49 ± 3%CVCmax, P > 0.05). Combined A‐I +l‐arg augmented %CVCmax in both subject groups compared with their respective control sites (HTN, 60 ± 7%CVCmaxversus AMN, 61 ± 3%CVCmax, both P < 0.05 versus respective control sites). Vasodilatation is attenuated with HTN due to decreased NO‐dependent vasodilatation and can be augmented with arginase inhibition but not l‐arg supplementation, suggesting that arginase is up‐regulated with HTN.
Multi‐tasking in the spinal cord – do ‘sympathetic’ interneurones work harder than we give them credit for?
Authors: Deuchars Susan A.
Published: March 2007

The role of interneurones in the control of sympathetic activity has been somewhat of a mystery since, for many years, it was difficult to target these cells for study. Recently scientists have started to unravel the action potential properties of these neurones, where they receive their inputs from and where they project to. This review looks at the information known to date about sympathetic interneurones. The locations of these neurones and their local axonal ramifications suggest that they play a more widespread function than previously thought. Therefore the data to support such a theory are also examined.
Activity‐dependent changes in temporal components of neurotransmission at the juvenile mouse calyx of Held synapse
Authors: Fedchyshyn Michael J. , Wang Lu‐Yang
Published: March 2007

The temporal fidelity of synaptic transmission is constrained by the reproducibility of time delays such as axonal conduction delay and synaptic delay, but very little is known about the modulation of these distinct components. In particular, synaptic delay is not generally considered to be modifiable under physiological conditions. Using simultaneous paired patch‐clamp recordings from pre‐ and postsynaptic elements of the calyx of Held synapse, in juvenile mouse auditory brainstem slices, we show here that synaptic activity (20–200 Hz) leads to activity‐dependent increases in synaptic delay and its variance as well as desynchronization of evoked responses. Such changes were most robust at 200 Hz in 2 mm extracellular Ca2+ ([Ca2+]o), and could be attenuated by lowering [Ca2+]o to 1 mm, increasing temperature to 35°C, or application of the GABABR agonist baclofen, which inhibits presynaptic Ca2+ currents (ICa). Conduction delay also exhibited slight activity‐dependent prolongation, but this prolongation was only sensitive to temperature, and not to [Ca2+]o or baclofen. Direct voltage‐clamp recordings of ICa evoked by repeated action potential train template (200 Hz) revealed little jitter in the timing and kinetics of ICa under various conditions, suggesting that increases in synaptic delay and its variance occur downstream of Ca2+ entry. Loading the Ca2+ chelator EGTA‐AM into terminals reduced the progression rate, the extent of activity‐dependent increases in various delay components, and their variance, implying that residual Ca2+ accumulation in the presynaptic nerve terminal induces these changes. Finally, by applying a test pulse at different intervals following a 200 Hz train (150 ms), we demonstrated that prolongation in the various delay components reverses in parallel with recovery in synaptic strength. These observations suggest that a depletion of the readily releasable pool of SVs during high‐frequency activity may downregulate not only synaptic strength but also decrease the temporal fidelity of neurotransmission at this and other central synapses.
Central Roles of Small GTPases in the Development of Cell Polarity in Yeast and Beyond
Authors: Park Hay-Oak , Bi Erfei
Published: March 2007

The establishment of cell polarity is critical for the development of many organisms and for the function of many cell types. A large number of studies of diverse organisms from yeast to humans indicate that the conserved, small-molecular-weight GTPases function as key signaling proteins involved in cell polarization. The budding yeastSaccharomyces cerevisiaeis a particularly attractive model because it displays pronounced cell polarity in response to intracellular and extracellular cues. Cells ofS. cerevisiaeundergo polarized growth during various phases of their life cycle, such as during vegetative growth, mating between haploid cells of opposite mating types, and filamentous growth upon deprivation of nutrition such as nitrogen. Substantial progress has been made in deciphering the molecular basis of cell polarity in budding yeast. In particular, it becomes increasingly clear how small GTPases regulate polarized cytoskeletal organization, cell wall assembly, and exocytosis at the molecular level and how these GTPases are regulated. In this review, we discuss the key signaling pathways that regulate cell polarization during the mitotic cell cycle and during mating.
Insertion Sequence Diversity in Archaea
Authors: Filée J. , Siguier P. , Chandler M.
Published: March 2007

Insertion sequences (ISs) can constitute an important component of prokaryotic (bacterial and archaeal) genomes. Over 1,500 individual ISs are included at present in the ISfinder database (www-is.biotoul.fr), and these represent only a small portion of those in the available prokaryotic genome sequences and those that are being discovered in ongoing sequencing projects. In spite of this diversity, the transposition mechanisms of only a few of these ubiquitous mobile genetic elements are known, and these are all restricted to those present in bacteria. This review presents an overview of ISs within the archaeal kingdom. We first provide a general historical summary of the known properties and behaviors of archaeal ISs. We then consider how transposition might be regulated in some cases by small antisense RNAs and by termination codon readthrough. This is followed by an extensive analysis of the IS content in the sequenced archaeal genomes present in the public databases as of June 2006, which provides an overview of their distribution among the major archaeal classes and species. We show that the diversity of archaeal ISs is very great and comparable to that of bacteria. We compare archaeal ISs to known bacterial ISs and find that most are clearly members of families first described for bacteria. Several cases of lateral gene transfer between bacteria and archaea are clearly documented, notably for methanogenic archaea. However, several archaeal ISs do not have bacterial equivalents but can be grouped intoArchaea-specific groups or families. In addition to ISs, we identify and list nonautonomous IS-derived elements, such as miniature inverted-repeat transposable elements. Finally, we present a possible scenario for the evolutionary history of ISs in theArchaea.
Biosynthesis of Ether-Type Polar Lipids in Archaea and Evolutionary Considerations
Authors: Koga Yosuke , Morii Hiroyuki
Published: March 2007

This review deals with the in vitro biosynthesis of the characteristics of polar lipids in archaea along with preceding in vivo studies. Isoprenoid chains are synthesized through the classical mevalonate pathway, as in eucarya, with minor modifications in some archaeal species. Most enzymes involved in the pathway have been identified enzymatically and/or genomically. Three of the relevant enzymes are found in enzyme families different from the known enzymes. The order of reactions in the phospholipid synthesis pathway (glycerophosphate backbone formation, linking of glycerophosphate with two radyl chains, activation by CDP, and attachment of common polar head groups) is analogous to that of bacteria.
sn
-Glycerol-1-phosphate dehydrogenase is responsible for the formation of the
sn-
glycerol-1-phosphate backbone of phospholipids in all archaea. After the formation of two ether bonds, CDP-archaeol acts as a common precursor of various archaeal phospholipid syntheses. Various phospholipid-synthesizing enzymes from archaea and bacteria belong to the same large CDP-alcohol phosphatidyltransferase family. In short, the first halves of the phospholipid synthesis pathways play a role in synthesis of the characteristic structures of archaeal and bacterial phospholipids, respectively. In the second halves of the pathways, the polar head group-attaching reactions and enzymes are homologous in both domains. These are regarded as revealing the hybrid nature of phospholipid biosynthesis. Precells proposed by Wächtershäuser are differentiated into archaea and bacteria by spontaneous segregation of enantiomeric phospholipid membranes (with
sn-
glycerol-1-phosphate and
sn-
glycerol-3-phosphate backbones) and the fusion and fission of precells. Considering the nature of the phospholipid synthesis pathways, we here propose that common phospholipid polar head groups were present in precells before the differentiation into archaea and bacteria.
Do seed banks confer resilience to coastal wetlands invaded by Typha ×glauca?
Authors: Frieswyk Christin B. , Zedler Joy B.
Published: March 2007

Historically, seed banks conferred resilience to Laurentian Great Lakes coastal wetlands by providing propagules of many species to replace invasive plants, such as Typha ×glauca Godr. After flooding, the seed bank could allow recovery of wetland composition and structure as the water levels fall. Using the seedling emergence method to estimate seed density, species and guild richness, and floristic quality, we evaluated the resilience of five wetlands along the western coast of Green Bay, Lake Michigan by comparing seed bank attributes in areas invaded by Typha to those of neighboring uninvaded areas and to attributes of the extant vegetation. Resilience decreased from north to south among the five wetlands, mirroring a gradient of decreasing water quality. The invasive Lythrum salicaria L. dominated the seed bank of all five wetlands despite low relative abundance in the extant vegetation. The resilience of Green Bay coastal wetlands is threatened by the overwhelming presence of L. salicaria in the seed bank. Because the seed bank holds a wetland’s potential to be renewed by the natural hydrological cycle, seed bank assessment should be a routine measure of wetland resilience.
The structure of genetic diversity in Engelmann spruce and a comparison with blue spruce
Authors: Ledig F. Thomas , Hodgskiss Paul D. , Johnson David R.
Published: March 2007

Genetic diversity and genetic structure in Engelmann spruce (Picea engelmannii Parry ex Engelm.) were interpreted with respect to the effects of glacial and interglacial displacement and compared with patterns in blue spruce (Picea pungens Engelm.), which occupies a range well south of the last glacial front. On average, Engelmann spruce populations were polymorphic at 80% of 24 isozyme loci, with 2.4 alleles per locus and expected heterozygosity of 0.255. The respective means for four populations of blue spruce were 42.7%, 1.6 alleles, and 0.138. Of total diversity, 14.7% was among populations in Engelmann spruce and 8.6% in blue spruce. In Engelmann spruce, numbers of alleles increased from south to north. Recent bottlenecks were indicated in the three southernmost populations of Engelmann spruce and in the northernmost population of blue spruce. Cluster analysis divided Engelmann spruce into a northern group and a Southwestern group; however, populations from Utah were distributed among both clusters. Genetic distance was correlated with geographic distance between northern populations but not between Southwestern populations, where drift predominated over gene flow. In two Engelmann spruce populations from Utah, multilocus outcrossing rates were 0.951 (±0.016) and 0.940 (±0.071). At Flys Peak, Arizona, the southernmost location of Engelmann spruce, outcrossing was also high, 0.899 (±0.017). Thus, inbreeding coefficients observed for parental (–0.104 to 0.047) and filial (0.011 to 0.026) generations were low. Although Engelmann spruce seemed genetically robust, the evidence of bottlenecks in the southern extreme of its range suggested future problems in an era of global warming.
Relationships between flowering phenology, plant size, and female reproductive output in a dioecious shrub, Ilex leucoclada (Aquifoliaceae)
Authors: Torimaru Takeshi , Tomaru Nobuhiro
Published: March 2007

Flowering phenology is critical for reproduction in dioecious species, but selection on timing of flowering may be weakened by physiological factors such as plant size, and external factors such as climate. We investigated the flowering phenology of male and female adults, and female reproductive output, in 10 patches with various sex ratios, of the dioecious shrub Ilex leucoclada (Maxim.) Makino over three consecutive years in an old-growth beech forest. Sexual dimorphism was observed in flowering amplitude, but not in other traits examined, including flowering onset date, duration, peak date, and synchrony with plants of the opposite sex in the population. Plant size had a consistent, positive effect on flowering amplitude in both sexes throughout the study period, but its effects on other factors, including the extent of fruit set, varied. Females in mixed patches showed higher fruit set than those in female patches. Furthermore, although the reproductive output of the female I. leucoclada plants is likely to be affected by flowering phenological traits in the mixed patches, the importance of these factor is probably modulated by other variables, including precipitation (which had a major effect on male flowering patterns) and the spatial distribution of the males.
Local seed rain and seed bank in a species-rich grassland: effects of plant abundance and seed size
Authors: Jakobsson Anna , Eriksson Ove , Bruun Hans Henrik
Published: March 2007

In this study, we examined the relationship between seed size, seed rain, and seed bank in a species-rich perennial grassland in Sweden. The seed rain was monitored by 100 seed traps placed in a 10 m × 10 m area for 1 year. The seed bank was sampled by taking 100 soil samples, each in close vicinity to a seed trap. Abundance of reproductive ramets in the area was estimated, since this is likely to affect the proportion of hit seed traps and seed bank samples. When abundance of reproductive ramets was accounted for, we found a negative relationship between seed size and proportion of hit seed bank samples, but we found no relationship between seed size and proportion of hit seed traps. We found strong positive relationships between the abundance of reproductive ramets and proportion of hit seed traps and seed bank samples. We also found strong positive relationships between abundance of reproductive ramets and abundance of seeds in the seed rain and the seed bank, but no relationship between seed size and abundance of seeds in the seed rain or the seed bank. We discuss these results in the context of theory suggesting that large-seeded and small-seeded species may coexist because of a trade-off between colonization and competitive abilities, where smaller-seeded species are able to reach more sites than seeds of larger-seeded species, because they are more numerous and (or) better dispersed.
Relationships between shoot size and branching patterns in 10 broad-leaved tall tree species in a Japanese cool-temperate forest
Authors: Yagi Takanobu
Published: March 2007

Within-tree variations in branching patterns (the patterns of daughter shoot production by mother shoots) are the basis of tree architectural plasticity and, therefore, were studied in 10 cool-temperate broad-leaved tall tree species including three species with distinct short shoots. The relationships between mother shoot length versus branching patterns (i.e., the number and size of daughter shoots) were quantified for each species using regression equations. The number and stem length of daughter shoots were greater on longer mother shoots, although the majority of daughter shoots were short on mother shoots of any size. The magnitude of lateral spread of the mother shoot – daughter shoot system relative to that of its main axis extension increased with increasing mother shoot length, indicating weaker apical control on longer mother shoots. Among species, the lower limit of daughter shoot length was shorter and the frequency of short daughter shoots was greater on mother shoots of species with more distinct short shoots. This indicates that species with distinct short shoots effectively avoid branch overcrowding by minimizing daughter shoot extension. Differences in branching patterns among mother shoots of different sizes are discussed in relation to their functional importance for tree architectural development.
Lichens from the Hudson Bay Lowlands: diversity in the southeastern peatlands of Wapusk National Park, Manitoba
Authors: Piercey-Normore Michele D.
Published: March 2007

Peatlands form an important component of the Northern Hemisphere. They provide substrate for lichen growth and are used by large mammals such as polar bears, caribou, and humans. This study provides the first annotated species list of lichens on the peatlands of Wapusk National Park, Manitoba. It also provides insight into the chemical and genetic diversity of members of Cladonia that dominate the peatlands. Ninety-three species of lichen-forming fungi are reported for the peatlands, fewer than that reported for the coastal beach ridges in Wapusk National Park. This study reports six species of cyanobacterial lichens and two species of Basidiomycete lichens, including two new occurrences for Manitoba, Leptogium intermedium (Arnold) Arnold and Lichenomphalia hudsoniana (H.S. Jenn.) Redhead, Lutzoni, Moncalvo, & Vilgalys. Both chemical diversity in the genus Cladonia and genetic diversity within the species, Cladonia arbuscula (Wallr.) Flotow, were lower than those of a comparable study in a more southerly location. The abundance of apothecia produced by crustose species on the peatlands suggests that crustose species were predominantly sexually reproducing. Foliose species showed production of both sexual and vegetative features, and the fruticose species were mainly vegetatively reproducing. The study raises questions on life history strategies, the influence of habitat on lichen chemistry, and genetic variation of lichen algae in northern environments.
Magnesium localization in shoot apices during flower induction in Pharbitis nil
Authors: Kobayashi Natsuko I. , Tanoi Keitaro , Nakanishi Tomoko M.
Published: March 2007

We present the potential involvement of Mg2+ in the flowering mechanism in the shoot apex of the short-day plant Pharbitis nil (L.). To analyze elemental distribution in shoot apical meristems, fluorescence staining methods with Mag-fluo-4 AM and Fluo-3 AM were used. The former is sensitive to both Mg2+ and Ca2+, and the latter is a specific Ca2+ indicator. When plants were grown under continuous light conditions, some cells with intensive fluorescence of Mg2+ appeared in the top layers of the shoot apical meristem. During growth in the vegetative phase, cells in the center of the top layers accumulated large amounts of Mg2+. Exposure to a single 16 h short-day treatment induced the flowering process and dramatically reduced the fluorescence associated with Mg2+ accumulation in the top layers, suggesting that Mg2+ contributes to the flower induction process. The fluorescence associated with Ca2+ did not show this distribution difference between growth phases. A night-break treatment also influenced the fluorescence pattern. It was suggested for the first time that Mg2+ plays an important role in flower induction.
Heteropoly acid in ionic liquid — An efficient and recyclable system for one-pot three-component Mannich reaction
Authors: Rasalkar Meghana S , Bhilare Sachin V , Deorukhkar Amol R , Darvatkar Nitin B , Salunkhe Manikrao M
Published: March 2007

This paper describes a one-pot three-component Mannich reaction, catalyzed by phosphotungstic acid (H3PW12O40), a heteropoly acid in ionic liquid. The catalyst was found to be mild and efficient, and the protocol affords β-amino ketones in good yields under ambient conditions. Several ionic liquids and conventional organic solvents were employed for the reaction. The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) offered the best results in terms of yield of the products. It was observed that a homogeneous reaction medium proved beneficial for the yield of the reaction.Key words: Mannich reaction, β-amino ketones, phosphotungstic acid, ionic liquid, recyclability.
Synthesis of substituted 4-azaisoindoles — New tacrine analogues
Authors: Bekolo Henri , Kirsch Gilbert
Published: March 2007

The regioselective Friedländer reaction of 3-amino-4-cyanopyrroles with a series of cyclic ketones has enabled the first reported synthesis of substituted 4-azaisoindoles. Structurally, this new class of compounds stands for the first reported 4-azaisoindole tacrine analogues. A reaction mechanism for the formation of the reported 4-azaisoindoles is proposed.Key words: 4-azaisoindoles, tacrine, Friedländer reaction, pyrroles, mechanism.
Towards the development of a covalently tethered MALDI system — A study of allyl-modified MALDI matrixes
Authors: Martic Sanela , Brennan John D , Brook Michael A , Ackloo Suzanne , Nagy Noemi
Published: March 2007

An emerging application of matrix-assisted laser desorption ionization (MALDI) mass spectrometry is the analysis of low molecular weight (LMW) compounds, often via coupled liquid chromatography — MALDI-MS methods. However, in many cases, the low molecular weight region of MALDI mass spectra is obscured by the presence of signals originating from the matrix, suggesting that the development of tethered MALDI matrixes may be required to optimize MS performance for such compounds. To gain insight into potential sites for covalent attachment of MALDI matrixes, we have systematically investigated the role played by a variety of functional group motifs in determining matrix efficiency for three common MALDI matrixes, as judged both by total signal intensity and background noise from matrix decomposition for a set of LMW compounds. A series of allyl derivatives of standard matrixes was prepared, and the efficiency of these materials in the MALDI experiment was measured. All modifications of established matrixes, e.g., 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and caffeic acid (CA), or close analogues led to decreased absolute signal intensity and signal-to-background levels. Improved performance was generally observed with (i) the presence of a phenolic group (carboxylic acids were less effective) (ii) crystalline derivatives, and (iii) compounds that had high extinction coefficients at wavelengths near to that of the exciting laser (337 nm). The most interesting derivatives were the O-allyl ether (15) and N-allyl amide (16) of caffeic acid. These compounds did not facilitate signals from all four analytes tested. However, the observed spectra contained fewer signals from the matrix than from the parent compound CA. These compounds demonstrate that functionalization of MALDI matrixes, ultimately leading to tethered matrixes, is possible without jeopardizing signal intensity.Key words: MALDI, protected matrix, phenol, caffeic acid, allyl ether.
The reactivity of an anionic gallium N-heterocyclic carbene analogue with a solution stable digermene
Authors: Rupar Paul A , Jennings Michael C , Baines Kim M
Published: March 2007

The reaction of the anionic gallium(I) N-heterocyclic carbene (NHC) analogue 3 with the solution stable digermene 5 results in the formation of the gallium NHC – germylene complex 8. The gallium NHC – germylene complex 8 was derivatized with CH3I and (CH3)3SiCl.Key words: digermene, carbene analogue, germylene, gallium(I).
GLASS STABILITY EFFECT OF IRON OXIDE ADDED TO ALKALINE EARTH BORATE GLASSES
Authors: SIMON V. , RIEDL P. , TATARU E.
Published: March 2007

Glass stability and the structural role of iron oxide in x Fe 2 O 3(100-x)[ B 2 O 3– MO ] systems ( M=Ca , Sr or Ba , 0≤x≤30 mol%) were estimated from differential thermal analysis. The results suggest structural changes characteristic for the transition from short range to intermediate range order as the cationic field strength of the alkaline earths increases. In contrast, the iron addition has an opposite effect and determines a higher glass stability of these systems.
ELECTRICAL RESISTIVITY AND MAGNETO-RESISTANCE OF La0.7Sr0.3-xAgxMnO3 PELLETS BETWEEN 10 AND 450 K
Authors: BATTABYAL MANJUSHA , DEY T. K.
Published: March 2007

The temperature dependence of the electrical resistivity and magneto-resistance in silver substituted La 0.7 Sr 1-x Ag x MnO 3 pellets prepared by a simple pyrophoric method has been investigated between 10 and 450 K for H=0 and 0.8T. Ag substitution enhances the conductivity of this system. Curie temperature (T C ) also increases sharply from ~303 K (x=0.05) to ~363 K (x=0.25). Above the metal-insulator transition temperature (T MI ), the electrical resistivity is well represented by usual adiabatic polaronic transport, while in the ferromagnetic region at low temperatures, the resistivity data shows an excellent agreement to an expression containing the residual resistivity, two-magnon scattering term and the term associated with small-polaron metallic conduction, which involves a relaxation time due to a soft optical phonon mode. Based on a scenario that the doped manganites consist of phase separated ferromagnetic metallic and paramagnetic insulating regions, all the features of the temperature variation of the resistivity between ~50 K and 300 K could be described very well. All the Ag doped samples reveal resistivity minimum, which is strongly field dependent (H=0.8 T ). These minimum results have been analyzed and the observed field dependent minimum is found to be in excellent agreement to those calculated from the model based on charge carrier tunneling between antiferro-magnetically coupled grains. Field dependence of magnetoresistance at various temperatures below T c is accounted fairly well by a phenomenological model based on spin polarized tunneling at the grain boundaries. The contributions from the intrinsic part arising from DE mechanism, as well as the part originating from intergranular spin polarized tunneling are also estimated.
THE HEXAGONAL RECURSIVE APPROXIMATION WITH MULTISITE-INTERACTION ISING MODEL FOR THE SOLID AND FLUID 3He SYSTEM
Authors: ANANIKYAN L. N.
Published: March 2007

Consider the Heisenberg model with two-, three-, four-, five-, and six-spin exchanges interactions applied on a hexagon in strong magnetic field for 3 He system. The recursive lattice is constructed by adding next shells (branches) of hexagons on vertexes of previous one. The exact rational recursion relations for partition function are obtained on this recursive lattice with Ising model approximation for multiple-spins interaction. This approach gives us an opportunity to describe solid and fluid 3 He films absorbed on the surface of graphite which have a structure of two-dimensional regular triangular lattices. Using dynamical system method of one-dimensional rational mapping allows us to research the magnetic behavior of solid and fluid 3 He films, depending on the values of the exchanging parameters and magnetic field. The magnetization plateaus m=0 and m/m sat =2/3 are obtained in low temperatures and different exchange parameters. The bifurcation points corresponding to the second order phase transition are observed. There is one period doubling that occurs in anti-ferromagnetic case at low temperatures. The existence of sublattices in the considered model allows us to get modulated phases.
A NEW HIERARCHY OF DISCRETE INTEGRABLE MODEL AND ITS DARBOUX TRANSFORMATION
Authors: DING HAI-YONG , XU XI-XIANG , YANG HONG-XIANG , TIAN XIANG
Published: March 2007

A new isospectral problem is proposed and the corresponding integrable equation hierarchy is given. A Darboux transformation (DT) is derived to obtain the exact solutions for the typical lattice soliton equations.
SOLO SONGS AND SYMPHONIES: ETHNIC MINORITY INDIAN WOMEN ENTREPRENEURS IN NEW ZEALAND
Authors: PIO EDWINA
Published: March 2007

Diverse demographic components internationally have resulted in an emerging awareness of ethnic minority entrepreneurship. In New Zealand, Indians are an ethnic minority who form approximately 1.7% of the population. Based on qualitative research methodology and grounded in feminine epistemology, the entrepreneurial journey of Indian women entrepreneurs in New Zealand is explored. The findings reveal multiple layers of meaning and the recoding of connections as the women seek to both confront and co-exist with their Indian past and their New Zealand present - a border zone, where entrepreneurship serves as a focal point for making a difference in the host country New Zealand.
OPERATIONALIZING SME NETWORK RESOURCES
Authors: VUORINEN TERO , VARAMÄKI ELINA , KOHTAMÄKI MARKO , PIHKALA TIMO
Published: March 2007

In presenting two perspectives through which SME networking can be discussed, namely a system view and a view that considers networks as entities, this paper aims to contribute to the current discourse on SME network resources. A network-level performance measurement system emphasizes win-win situations in a network between the leader company and the other members of the network. The main objective of the present paper is to develop a measurement system for analyzing the value of resources and competencies in a production network, which can be used to complement existing network-level performance measurement systems. By taking into account the resources in a network environment in this way, the value of the whole network and its resources comes to represent the sum of the resources fit with customer needs, the co-operation ability and willingness of the network, and the entrepreneurial capability of the network to create new business opportunities.
DRIVING FORCE AND KINETIC RELATIONS FOR SCALAR CONSERVATION LAWS
Authors: KNOWLES JAMES K.
Published: March 2007

This paper is concerned with the circumstances under which the dissipative character of a one-dimensional scalar conservation law may be described by a formalism strictly analogous to that arising naturally in the dynamics of nonlinearly elastic materials. It is shown that this occurs if and only if the entropy density, entropy flux pair associated with the conservation law takes a particular form. We compare the admissibility condition associated with this special entropy with other admissibility criteria such as those of Lax, Oleinik and regularization theory. Using the special entropy, we consider the Riemann problem for an example in which genuine nonlinearity fails and a kinetic relation is needed to determine a unique solution.
Forebrain regions associated with postexercise differences in autonomic and cardiovascular function during baroreceptor unloading
Authors: Kimmerly D. S. , Wong S. W. , Salzer D. , Menon R. , Shoemaker J. K.
Published: March 2007

The cortical regions representing peripheral autonomic reactions in humans are poorly understood. This study examined whether changes in forebrain activity were associated with the altered physiological responses to lower body negative pressure (LBNP) following a single bout of dynamic exercise (POST-EX). We hypothesized that, compared with the nonexercised condition (NO-EX), POST-EX would elicit greater reductions in stroke volume (SV) and larger increases in heart rate (HR) and muscle sympathetic nerve activity (MSNA) during LBNP (5, 15, and 35 mmHg). Forebrain neural activity ( n = 11) was measured using blood oxygen level-dependent (BOLD) functional magnetic resonance imaging. HR, SV, arterial blood pressure (ABP), and MSNA were collected separately. Compared with NO-EX, baseline ABP was reduced, whereas HR and total vascular conductance (TVC) were elevated in POST-EX ( P < 0.05). In both conditions, 5 mmHg LBNP did not elicit a change (from baseline) in any physiological parameter. Compared with NO-EX, 35 mmHg LBNP-mediated decreases in SV and TVC produced greater increases in HR and MSNA during POST-EX ( P < 0.05). The right posterior insula and dorsal anterior cingulate cortex demonstrated a larger decrease in BOLD at 5 mmHg LBNP but greater BOLD increase at 15 and 35 mmHg LBNP POST-EX vs. NO-EX ( P < 0.005). Conversely, the thalamus and ventral medial prefrontal cortex displayed the opposite BOLD activity pattern (i.e., larger increase at 5 mmHg LBNP but greater decrease at 15 and 35 mmHg LBNP POST-EX vs. NO-EX). Our findings suggest that discrete forebrain regions may be involved with the generation of baroreflex-mediated sympathetic and cardiovascular responses elicited by moderate LBNP.