bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Sodium Potassium Niobate: A Diffusion Couples Study
Authors: Malic Barbara , Jenko Darja , Holc Janez , Hrovat Marko , Kosec Marija
Published: April 2008

The sequence of reactions during the synthesis of sodium niobate, potassium niobate, and sodium potassium niobate from alkaline carbonates and niobium oxide has been studied by diffusion couples in the temperature range between 500° and 700°C for up to 48 h. The reactions proceed by coupled diffusion of alkaline and oxygen ions into niobium oxide. The first phase to form at the interface Na2CO3/Nb2O5 is Na2Nb4O11 at 500°C. The perovskite phase forms only after heating at 700°C at the boundary between Na2Nb4O11 and Na2CO3. In the K2CO3/Nb2O5 diffusion couple, the sequence of phases after heating at 600°C is Nb2O5/K6Nb10.88O30/K4Nb6O17/KNbO3/K2CO3. In the (K2CO3+Na2CO3)/Nb2O5 diffusion couple the (K,Na)NbO3 solid solution forms via the intermediate phase (K,Na)2Nb4O11 at 600°C. The order of magnitude of the parabolic reaction rate constant for the diffusion‐controlled reaction at 600°C is about 10−15 m2/s for the (K2CO3+Na2CO3)/Nb2O5 and the K2CO3/Nb2O5 systems, which is about one order of magnitude less than that for Na2CO3/Nb2O5 (10−14 m2/s). The reaction rate in the ternary system is determined by the diffusion of the slower species, i.e., the potassium ions.
Clinical Outcome of Mini‐Screws Used as Orthodontic Anchorage
Authors: Justens Emmanuel , De Bruyn Hugo
Published: April 2008

Background: Implants and orthodontics are an important combination to obtain intraoral anchorage and eliminate the disadvantages linked with extraoral anchorage such as compliance problems, aesthetical, and social factors. The mini‐screw is a simple, relatively low‐cost method to provide intraoral anchorage.

Purposes: The aims of this study were to evaluate clinical success and longevity of mini‐screws during orthodontic treatment and to assess the patient's opinion.

Materials and Methods: Fifty mini‐screws were inserted in the mandible and maxilla of 21 patients with a flapless technique under local anesthesia. The patients were recalled after 2 weeks and from then on every other 2 months, and periodontal parameters and stability of the screws were evaluated at regular intervals. Patients received a questionnaire to assess their opinion regarding the treatment.

Results: Thirty‐three mini‐screws (64%) remained stable sufficiently long to obtain the effect during the orthodontic movement. The survival was comparable in mandible or maxilla, and not related to the orthodontic forces applied or time of activation of the load. The results do suggest that a waiting period of 1 week before loading improves success, and mini‐screws inserted into the anterior region score better also compared to the posterior region. Initial periodontal parameters, which are very important in prognosis of orthodontic treatment, are not influencing the success rate in the examined group. Patients complained in 40–50% of the cases of pain during or after surgery, but this did not negatively affect the final general satisfaction with the treatment.

Conclusion: The mini‐screw implant is an easy and an inexpensive method for temporary anchorage of orthodontic appliances. The functioning time is short, however, and retreatment may often be required.
Two Alternative Surgical Techniques for Enhancing Primary Implant Stability in the Posterior Maxilla: A Clinical Study Including Bone Density, Insertion Torque, and Resonance Frequency Analysis Data
Authors: Turkyilmaz Ilser , Aksoy Utku , McGlumphy Edwin A.
Published: April 2008

Background: The primary stability of dental implants associated with resistance to micromotion during healing is affected by surgical technique and implant design, which are important especially in the soft bone, where implant failures are more likely.

Purposes: This study was designed to compare the parameters associated with implant insertion using two different methods of enhancing implant primary stability and to identify any relationship between these parameters at implant insertion.

Materials and Methods: A total of 60 implants were placed in the maxillary posterior regions of 22 patients. The bone densities at the implant sites were recorded using a computerized tomography machine in Hounsfield unit (HU). The maximum insertion torque data were recorded with the Osseocare™ (Nobel Biocare AB, Göteborg, Sweden) equipment, while resonance frequency analysis (RFA) measurements were taken using an Osstell™ (Integration Diagnostics AB, Göteborg, Sweden) machine at implant surgery. Comparisons including HU, Ncm, and implant stability quotient were made between two control groups (C1 and C2), and corresponding four test groups (T1–T4) using thinner drills to enhance primary implant stability.

Results: Two implants were lost, meaning an overall implant survival rate of 96.6% after 3 ± 1 years. When compared to control groups, significantly higher mean maximum insertion torque and RFA values were found for corresponding test groups. In addition, strong correlations were observed between the bone density and insertion torque, and implant stability values at implant placement.

Conclusion: The results of this study suggest that using thinner drills for implant placement in the maxillary posterior region where bone quality is poor may improve the primary implant stability, which helps clinicians to obtain higher implant survival rates.
Determination of Bone Quality of 372 Implant Recipient Sites Using Hounsfield Unit from Computerized Tomography: A Clinical Study
Authors: Turkyilmaz Ilser , Ozan Oguz , Yilmaz Burak , Ersoy Ahmet Ersan
Published: April 2008

Background: The type and architecture of bone are very important factors in the successful implant treatment, and it is manifested that higher implant failure is more likely in the poorer quality of bone. Conventional bone classifications have recently been questioned because they are subjective and retrospective.

Purpose: This clinical study aimed to determine the variations of the bone density in dental implant recipient sites using computerized tomography (CT).

Materials and Methods: The study group comprised of randomly selected 140 patients with 372 implant sites. Recipient sites for implant placement were determined based on CT data using implant planning StentCad software (Media Lab Software, La Spezia, Italy). The mean bone density values in Hounsfield unit (HU) of the simulated implant areas were recorded using the StentCad software.

Results: The HU values ranged from 68 to 1,603 HU. It was found that mean bone density values were 927 ± 237, 721 ± 291, 708 ± 277, and 505 ± 274 HU in the anterior mandible, posterior mandible, anterior maxilla, and posterior maxilla, respectively.

Conclusion: Preoperative CT examination may be a useful method for determining the bone density of recipient areas before implant placement, and this valuable information about bone quality helps clinicians to make better treatment planning regarding the implant positions.
Anatomical Bases for the Insertion of Zygomatic Implants
Authors: Rossi Marcelle , Duarte Luís Rogério , Mendonça Robson , Fernandes Atson
Published: April 2008

Purpose: The purpose of this study was to obtain anatomical information for installing four zygomatic implants, by measurements of maxillae and zygomata.

Materials and Methods: Linear and angular measurements were obtained from the maxillae and zygomata of 40 dry skulls.

Results: Based on mean and standard deviation values, the installation angle of the additional implant in the four zygoma technique was between 25° and 47°, and that of the conventional zygomatic implant was between 39° and 62°. The distance between the alveolar crest in the canine region and the lateral margin of the orbital socket was 53.42 mm, and between the alveolar crest in the premolar region and the area closest to the lateral margin of the orbital socket was 42.47 mm.

Conclusions: When the angle of installation of the additional implant is less than 25° and that of the conventional zygomatic implant is less than 39°, perforation of the maxilla, zygoma, or the infratemporal fossa must be avoided. When the angle of installation of an additional implant is greater than 47° and that of the conventional zygomatic implant is greater than 62°, perforation of the orbital floor must be avoided. The length of an additional implant was greater than the length of a conventional zygomatic implant, and should be measured prior to drilling, because the greatest value found for this distance was 61.94 mm, while the maximum length of the zygomatic implants currently available on the market is 52.5 mm.
Marginal Bone Loss at Implants: A Retrospective, Long‐Term Follow‐Up of Turned Brånemark System® Implants
Authors: Pikner Solweig Sundén , Gröndahl Kerstin , Jemt Torsten , Friberg Bertil
Published: April 2008

Background: Lately, presence of progressive bone loss around oral implants has been discussed.

Purpose: The aim of this study was to report in a large patient group with different prosthetic restorations marginal bone level and its change as measured in radiographs obtained from prosthesis insertion up to a maximum 20 years in service. Further, it also aimed to study the impact of gender, age, jaw, prosthetic restoration, and calendar year of surgery.

Materials and Methods: Out of 1,716 patients recorded for clinical examination during 1999, 1,346 patients (78.4%) could be identified. A total of 640 patients (3,462 originally installed Brånemark System® implants, Nobel Biocare, Göteborg, Sweden) with a follow‐up of ≥5 years were included in the study, while patients with continuous overdentures and augmentation procedures were not. Distance between the fixture/abutment junction (FAJ) and the marginal bone level was recorded.

Results: The number of implants with a mean bone level of ≥3 mm below FAJ increased from 2.8% at prosthesis insertion to 5.6% at year 1, and 10.8% after 5 years. Corresponding values after 10, 15, and 20 years were 15.2, 17.2, and 23.5%, respectively. Implant‐based bone loss was as a mean 0.8 mm (SD 0.8) after 5 years, followed by only minor average changes. Mean bone loss on patient level followed a similar pattern. Disregarding follow‐up time, altogether 183 implants (107 patients) showed a bone loss ≥3 mm from prosthesis insertion to last examination. Significantly larger bone loss was found the older the patient was at surgery and for lower jaw implants.

Conclusions: Marginal bone support at Brånemark implants was with few exceptions stable over years.
Influence of Defect Depth on Resonance Frequency Analysis and Insertion Torque Values for Implants Placed in Fresh Extraction Sockets: A Human Cadaver Study
Authors: Turkyilmaz Ilser , Sennerby Lars , Yilmaz Burak , Bilecenoglu Burak , Ozbek Esma Nida
Published: April 2008

Background: Clinical studies show promising outcomes with implants inserted at the time of extraction. However, this often results in an initial bone defect at the marginal region which preferably should heal for an optimal function. Therefore, monitoring of these implants is vital.

Purposes: The aims of this study were to determine the initial stability of implants placed into fresh extraction sockets, and to explore the correlations between the peri‐implant bone levels and implant stability parameters.

Materials and Methods: Six human cadaver mandibles including all natural teeth were selected for this study. All natural teeth were gently extracted, and 84 implants were immediately placed into fresh extraction sockets with five different implant depths. The maximum insertion torque values were recorded, and primary implant stability measurements were performed by means of resonance frequency analysis (RFA). The vertical distance between implant/abutment junction and the first bone–implant contact was recorded using a periodontal probe.

Results: It was found that the insertion torque and RFA were 28.9 ± 7 Ncm and 65.6 ± 9 implant stability quotient (ISQ), respectively, for 420 measurements from all 84 implants. Statistically significant correlation was found between insertion torque and ISQ values (r = 0.86; p < .001) for all implants. Both insertion torque and ISQ values dramatically decreased when the amount of peri‐implant vertical bone defect increased.

Conclusion: The results of this study demonstrated a linear relationship between peri‐implant vertical bone defect depth and RFA value. It is proposed that the RFA method is sensitive to detect changes of the marginal bone level and may be used to monitor healing of peri‐implant bone defects.
Radiographic Analyses of “Advanced” Marginal Bone Loss Around Brånemark® Dental Implants
Authors: Pikner Solweig Sundén , Gröndahl Kerstin
Published: April 2008

Background: Dental implant failures have a multifactorial background; dependency within patient/jaw exists. Failures caused by bone loss are rare. Lately, advanced bone loss around implants has been discussed.

Purposes: Our aim was to study advanced bone level changes (≥2 mm) regarding “clustering effect,” prediction, and dependency. Further, we also aimed to study if the number of radiographs/radiographic examinations could be reduced.

Materials and Methods: Six hundred and forty patients (3,462 Brånemark implants) with radiographic follow‐ups ≥5 years were included, whereas patients with overdentures and augmentation procedures were excluded.

Results: Progression rate for implants with advanced bone loss was largest during the first year; thereafter, slow. A cluster effect was found with more advanced bone loss in few patients. Position was important for lower jaw implants with larger bone loss for implants placed close to midline. Age, jaw type, and implant placement were identified as predictors. The longer the follow‐ups, the more bone loss around a randomly selected and examined implant, and the more implants per patient, the higher the risk for bone loss ≥2 mm around any other implant. Still, it seems safe to exclude radiographic follow‐ups during the first 5 years. Dependency within the patient was found, hence the “one‐implant‐per‐patient technique” can be applied.

Conclusion: The number of intraoral radiographs per examination and, more importantly, radiographic examinations can be reduced without jeopardizing good clinical management, a statement valid even for Brånemark implants with advanced bone loss.
Influence of Differently Oriented Dentin Surfaces and the Regional Variation of Specimens on Adhesive Layer Thickness and Bond Strength
Authors: PAZINATTO FLÁVIA BITTENCOURT , ATTA MARIA TERESA
Published: April 2008

Statement of the Problem:  Adhesive systems can spread differently onto a substrate and, consequently, influence bonding.

Purpose:  The purpose of this study was to evaluate the effect of differently oriented dentin surfaces and the regional variation of specimens on adhesive layer thickness and microtensile bond strength (MTBS).

Materials and Methods:  Twenty‐four molars were sectioned mesiodistally to expose flat buccal and lingual halves. Standardized drop volumes of adhesive systems (Single Bond [SB] and Prime & Bond 2.1 [PB2.1]) were applied to dentin according to the manufacturer's instructions. Teeth halves were randomly divided into groups: 1A‐SB/parallel to gravity; 1B‐SB/perpendicular to gravity; 2A‐PB2.1/parallel to gravity; and 2B‐PB2.1/perpendicular to gravity. The bonded assemblies were stored in 37°C distilled water for 24 hours and then sectioned to obtain dentin sticks (0.8 mm2). The adhesive layer thickness was determined in a light microscope (×200), and after 48 hours the specimens were subjected to MTBS test. Data were analyzed by one‐way and two‐way analysis of variance and Student–Newman–Keuls tests.

Results:  Mean values (MPa ± SD) of MTBS were: 39.1 ± 12.9 (1A); 32.9 ± 12.4 (1B); 52.9 ± 15.2 (2A); and 52.3 ± 16.5 (2B). The adhesive systems' thicknesses (µm ± SD) were: 11.2 ± 2.9 (1A); 18.1 ± 7.3 (1B); 4.2 ± 1.8 (2A); and 3.9 ± 1.3 (2B). No correlation between bond strength and adhesive layer thickness for both SB and PB2.1 (r = –0.224, p = 0.112 and r = 0.099, p = 0.491, respectively) was observed.

Conclusions:  The differently oriented dentin surfaces and the regional variation of specimens on the adhesive layer thickness are material‐dependent. These variables do not influence the adhesive systems' bond strength to dentin.

CLINICAL SIGNIFICANCE

Adhesive systems have different viscosities and spread differently onto a substrate, influencing the bond strength and also the adhesive layer thickness. Adhesive thickness does not influence dentin bond strength, but it may impair adequate solvent evaporation, polymer conversion, and may also determine water sorption and adhesive degradation over time. In the literature, many studies have shown that the adhesive layer is a permeable membrane and can fail over timebecause ofits continuous plasticizing and degradation when in contact with water. Therefore, avoiding thick adhesive layers may minimize these problems and provide long‐term success for adhesive restorations.
EFFECTS OF BLEACHING ON TOOTH STRUCTURE AND RESTORATIONS, PART III: EFFECTS ON DENTIN
Authors: Swift Edward J.
Published: April 2008

Tooth whitening has become a common treatment over the last 15 years, and much research has been reported on the effects of bleaching procedures on enamel, dentin, and restorative materials. We are presenting a series of Critical Appraisals covering recent research in this area. This installment describes studies regarding the effects on dentin properties and resin bonding to dentin.
Biologically active, non membrane‐anchored precursors – an overview
Authors: Dicou Eleni
Published: April 2008

Peptides function as chemical signals between cells of multicellular organisms via specific receptors on target cells. Many hormones, neuromodulators and growth factors are peptides. Peptide hormones and other biologically active peptides are synthesized as higher molecular weight precursor proteins (pro‐hormones), which must undergo post‐translational modification to yield the bioactive peptide(s). In many instances, more than one biologically active peptide is generated from one and the same precursor. In most cases, these precursors are biologically inert and their existence is confined to the membrane‐enclosed subcellular compartments where processing of the pro‐hormones takes place. A class of growth factors that derive from membrane‐anchored precursors which themselves are biologically active constitute an exception to this model. The list of the membrane‐anchored biologically active precursors has been the subject of specialized reviews. The present review focuses on precursors other than membrane‐anchored precursors, which were found to be biologically active and which often display different biological activities, and may mediate their effects via receptors independent from those of their generated peptides.
Treatment with small interfering RNA affects the microRNA pathway and causes unspecific defects in zebrafish embryos
Authors: Zhao Xiao‐Feng , Fjose Anders , Larsen Natalia , Helvik Jon V. , Drivenes Øyvind
Published: April 2008

MicroRNAs (miRNAs) are generated from primary transcripts through sequential processing by two RNase III enzymes, Drosha and Dicer, in association with other proteins. This maturation is essential for their function as post‐transcriptional regulators. Notably, Dicer is also a component of RNA‐induced silencing complexes, which incorporate either miRNA or small interfering RNA (siRNA) as guides to target specific mRNAs. In zebrafish, processed miRNAs belonging to the miR‐430 family have previously been shown to promote deadenylation and degradation of maternal mRNAs during early embryogenesis. We show that injection of one‐cell‐stage zebrafish embryos with siRNA causes a significant reduction in the endogenous levels of processed miR‐430 and other miRNAs, leading to unspecific developmental defects. Coinjection of siRNA with preprocessed miR‐430 efficiently rescued development. This indicates that the abnormalities generally observed in siRNA‐treated zebrafish embryos could be due to inhibition of miR‐430 processing and/or activity. Our results also suggest that the miRNA pathway in mammals, under some experimental or therapeutic conditions, may be affected by siRNA.
Role of Nitric Oxide Dependence on Nitric Oxide Synthase‐like Activity in the Water Stress Signaling of Maize Seedling
Authors: Hao Gang‐Ping , Xing Yu , Zhang Jian‐Hua
Published: April 2008

Nitric oxide (NO) has been known as an important signal in plant antioxidative defense but its production and roles in water stress are less known. The present study investigated whether NO dependence on a NO synthase‐like (NOS) activity is involved in the signaling of drought‐induced protective responses in maize seedlings.
NOS activity, rate of NO release and drought responses were analyzed when NO donor sodium nitroprusside (SNP), NO scavenger c‐PTIO (2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide) and NOS inhibitor L‐NAME (NG‐nitro‐L‐arginine methyl ester) were applied to both detached maize leaves and whole plants. Both NOS activity and the rate of NO release increased substantially under dehydration stress. The high NOS activity induced by c‐PTIO as NO scavenger and NO accumulation inhibited by NOS inhibitor L‐NAME in dehydration‐treated maize seedlings indicated that most NO production under water deficit stress may be generated from NOS‐like activity. After dehydration stress for 3 h, detached maize leaves pretreated with NO donor SNP maintained more water content than that of control leaves pretreated with water. This result was consistent with the decrease in the transpiration rate of SNP‐treated leaves subjected to drought treatment for 3 h. Membrane permeability, a cell injury index, was lower in SNP‐treated maize leaves under dehydration stress for 4 h when compared with the control leaves. Also, superoxide dismutase (SOD) activity of SNP combined drought treatment maize leaves was higher than that of drought treatment alone, indicating that exogenous NO treatment alleviated the water loss and oxidative damage of maize leaves under water deficit stress. When c‐PTIO as a specific NO scavenger was applied, the effects of applied SNP were overridden. Treatment with L‐NAME on leaves also led to higher membrane permeability, higher transpiration rate and lower SOD activities than those of control leaves, indicating that NOS‐like activity was involved in the antioxidative defense under water stress. These results suggested that NO dependence on NOS‐like activity serves as a signaling component in the induction of protective responses and is associated with drought tolerance in maize seedlings.
Effects on Genome Constitution and Novel Cell Wall Formation Caused by the Addition of 5RS Rye Chromosome to Common Wheat
Authors: Cheng Zhi‐Jun , Murata Minoru , Sodmergen  , Li Xiao‐Mei , Nian Hai , Wan Jian‐Min
Published: April 2008

The cytological instability of common wheat‐rye addition lines was investigated in the present study. The chromosome numbers of almost all addition lines were considerably stable, but those of CS + 5R were very variable. The rye chromosome added in this line was found to be much shorter than expected. Fluorescent in situ hybridization with 5S rDNA and the centromere‐specific probes clearly revealed that the short rye chromosome contains only a short arm of chromosome 5R (5RS). In this line, chromosome numbers of both 5RS and common wheat were changeable. The chromosome numbers ranged from 2n = 36 to 2n = 44 in the cells carrying two 5RS, and ranged from 2n = 31 to 2n = 44 in one 5RS cells. In addition to the chromosome instability, the multicells wrapped in a sac‐like structure were frequently observed in the root meristematic tissues of CS + 5RS after the enzyme treatment for chromosome preparation. Genomic in situ hybridization with rye DNA as a probe showed that all cells in sacs investigated were at the interphase stage and contained one or two 5RS chromosomes. An electron microscopic analysis revealed that the cells of CS + 5RS, particularly in sacs, have abnormal (irregular and curved) cell walls. These results indicate that 5RS has (a) specific factor(s) influencing the cell wall development as well as the genome stability.
Gene Structure and Expression of the High‐affinity Nitrate Transport System in Rice Roots
Authors: Cai Chao , Wang Jun‐Yi , Zhu Yong‐Guan , Shen Qi‐Rong , Li Bin , Tong Yi‐Ping , Li Zhen‐Sheng
Published: April 2008

Rice has a preference for uptake of ammonium over nitrate and can use ammonium‐N efficiently. Consequently, transporters mediating ammonium uptake have been extensively studied, but nitrate transporters have been largely ignored. Recently, some reports have shown that rice also has high capacity to acquire nitrate from growth medium, so understanding the nitrate transport system in rice roots is very important for improving N use efficiency in rice. The present study identified four putative NRT2 and two putative NAR2 genes that encode components of the high‐affinity nitrate transport system (HATS) in the rice (Oryza sativa L. subsp. japonica cv. Nipponbare) genome. OsNRT2.1 and OsNRT2.2 share an identical coding region sequence, and their deduced proteins are closely related to those from mono‐cotyledonous plants. The two NAR2 proteins are closely related to those from mono‐cotyledonous plants as well. However, OsNRT2.3 and OsNRT2.4 are more closely related to Arabidopsis NRT2 proteins. Relative quantitative reverse transcription‐polymerase chain reaction analysis showed that all of the six genes were rapidly upregulated and then downregulated in the roots of N‐starved rice plants after they were re‐supplied with 0.2 mM nitrate, but the response to nitrate differed among gene members. The results from phylogenetic tree, gene structure and expression analysis implied the divergent roles for the individual members of the rice NRT2 and NAR2 families. High‐affinity nitrate influx rates associated with nitrate induction in rice roots were investigated and were found to be regulated by external pH. Compared with the nitrate influx rates at pH 6.5, alkaline pH (pH 8.0) inhibited nitrate influx, and acidic pH (pH 5.0) enhanced the nitrate influx in 1 h nitrate induced roots, but did not significantly affect that in 4 to 8 h nitrate induced roots.
HYDROCARBON SOURCE ROCK ASSESSMENT AND REVISED BIOSTRATIGRAPHY OF DSDP SITE 369A, OFFSHORE NORTHWEST AFRICAN MARGIN
Authors: Cool T. , Katz B. , Dignes T. , Reimers D. , Fleisher R.
Published: April 2008

Deep Sea Drilling Project (DSDP) Site 369A, drilled off Cape Bajador, NW Africa, provided an opportunity to examine the source rock potential and biostratigraphy of the offshore Aaiun‐Tarfaya Basin. Within the Albian‐Campanian interval, total organic carbon (TOC) contents were found to be highly variable and cyclic, ranging from less than 0.5% to nearly 12%. Variations in hydrocarbon generation potential (S1 + S2) versus depth in general paralleled variations in TOC. Organic matter was generally marine in origin and oil‐prone.

The newly generated data reported in this paper expand the range of TOC values which have been reported from the study region. However, they also illustrate the kinds of problems which can be introduced as a result of sampling bias. Sampling for this study tended to focus on darker‐coloured, more organic‐rich lithologic core intervals, contrasting with previous shipboard analyses which appeared to have focused on lighter‐coloured intervals. Based on the abundance of calcareous nannofossils, the elevated TOC contents appear to have been, at least partly, driven by elevated surface productivity which in turn increased biological oxygen demand within the sediment.

New biostratigraphic data was used to identify an unconformity between the late Albianl early Cenomanian and the early Campanian successions, consistent with previous interpretations. Integration of the geochemical and biostratigraphic datasets indicates that these organic‐rich sediments are in general equivalent to Cretaceous Oceanic Anoxic Events 1B, 1D and 3. Considering the apparent net thickness of these oil‐prone sediments and the possibility that they may be widely distributed throughout the basin, they may have the potential to generate commercially significant volumes of oil where buried sufficiently deeply.
3D SEDIMENTARY MODELLING OF A MIOCENE DELTAIC RESERVOIR UNIT, SINCOR FIELD, VENEZUELA: A NEW APPROACH
Authors: Labourdette R. , Casas J. , Imbert P.
Published: April 2008

The “C2” unit in the Morichal Member of the Miocene Oficina Formation at the Sincor field (East Venezuela Basin) is characterised by a succession of superposed deltaic cycles which control vertical and horizontal reservoir connectivity. In order to model this reservoir in three dimensions, a workflow was developed which addressed a series of specific challenges. First, the deltaic nature of the succession required that both distributary channel and mouth bar sandbodies had to be modelled according to the defined sequence stratigraphic framework. Second, the relationship between distributary channels and mouth bars had to be honoured. A third issue was that individual distributary channel sandbodies were on occasion thicker than the cycle to which they belonged (i.e. they eroded down into the underlying cycle), and the relationship between mouth bar and channel sandbodies in adjacent sequences was therefore broken. Although conceptually simple from a geological viewpoint, this aspect proved particularly difficult during 3D modelling.

This paper discusses the construction of the stratigraphic model, as well as that of the channel and mouth bar models. The workflow is based on existing stochastic approaches, arranged in nested steps dependent on the stratigraphic framework and on defined depositional processes in order to simulate reservoir distribution and partitioning. By integrating sedimentological observations and interpretations with existing modelling procedures, a reliable reservoir model can be built. The model is based on the observed sequence stratigraphic framework, and its infill takes into account the relationship between distributary channels and mouth bar deposits, derived from depositional processes. The model provides realistic distributions of the channel fills and mouth bar deposits at Sincor field using a multi‐realisation scheme. Improved local vertical connectivity between individual sequences, caused by erosion of highstand mudstone seals and baffles, can effectively be simulated; this is of particular significance at Sincor where planned second‐phase heavy oil recovery will depend on the use of steam‐assisted gravity drainage.
The Effects of Feeding on Muscle Growth Dynamics and the Proliferation of Myogenic Progenitor Cells during Pike Perch Development (Sander lucioperca)
Authors: Ostaszewska Teresa , Dabrowski Konrad , Wegner Arleta , Krawiec Maria
Published: April 2008

The effects of feeding on the development and growth of pike perch muscle and on proliferation of their progenitor myogenic cells were evaluated. Larvae were fed starting on Day 5 after hatching with Artemia nauplii, two commercial diets (Aglo Norse [AN] and Biokyowa [BK]), and two formulated diets (C [nonhydrolyzed casein] and CH [25% casein hydrolysate]). The survival, body mass, and length of pike perch juveniles fed Artemia nauplii and AN and BK diets were significantly higher compared to the C and CH groups. The highest somatic growth rate was associated with an increased contribution of hyperplasia to white muscle growth. Significantly higher frequency of proliferating cell nuclear antigen‐ and Ki‐67‐positive nuclei in the white muscle of fish fed Artemia nauplii and commercial diets compared to those fed C and CH feeds indicates that feeding affected the number of fibers. The pike perch fed the CH diet exhibited significantly lower total cross‐section area and average fiber area, additionally to the pathological changes in muscle morphology. The larvae fed natural food and diets promoting a fast growth rate exhibited a higher contribution of hyperplasia to muscle growth, which in turn, promoted an increase in the body size of adult fish.
Response of African Catfish, Clarias gariepinus (Burchell, 1822), to Diets of Pigeon Pea, Cajanus cajan, Subjected to Different Processing Methods
Authors: Ogunji Johnny O. , Osuigwe Donald I. , Okogwu Okechukwu , Uwadiegwu Nicholas
Published: April 2008

Raw undehulled pigeon pea, Cajanus cajan, seeds were processed by toasting, boiling, and soaking before milling to produce pigeon pea meals (PPMs). African catfish, Clarias gariepinus, were fed eight diets formulated with these meals at two dietary inclusion levels of 600 and 650 
g/kg in combination with fish waste meal levels of 350 and 330 g/kg, respectively, to yield a protein and energy contents of 35.96 
± 
2.1% dry matter and 18.04 
± 
0.2 kJ/g. Fish (mean weight 0.46 
g) were weighed and distributed to 24 experimental tanks (seven fish per tank). Triplicate fish groups were fed restricted ration (5% of biomass) per day in two portions for 56 d in static water. Results showed that fish groups fed raw PPM diets had low body weight gain (BWG), inferior specific growth rate (SGR), and high feed conversion ratio (FCR) when compared to other feeding groups. The hematocrit, hemoglobin concentration, and red blood cell and white blood cell counts decreased significantly (P 
< 
0.05) with raw PPM diets. Slight decrease also was recorded among groups fed diets of other processing methods when compared with initial fish. However, soaking for 16 h enhanced best fish BWG, SGR, FCR, and hematological values and can be recommended as a good processing method of PPM for African catfish diets.
Genome‐Wide Analysis of Subependymomas Shows Underlying Chromosomal Copy Number Changes Involving Chromosomes 6, 7, 8 and 14 in a Proportion of Cases
Authors: Kurian Kathreena M. , Jones David T.W. , Marsden Faye , Openshaw Sam W.S. , Pearson Danita M. , Ichimura Koichi , Collins V. Peter
Published: April 2008

Subependymomas (SE) are slow‐growing brain tumors that tend to occur within the ventricles of middle‐aged and elderly adults. The World Health Organization classifies these tumors within the ependymoma group. Previous limited analysis of this tumor type had not revealed significant underlying cytogenetic abnormalities.

We have used microarray comparative genomic hybridization to study a series of SE (n = 12). A whole‐genome array at 0.97‐Mb resolution showed copy number abnormalities in five of 12 cases (42%). Two cases (17%) showed regions of loss on chromosome 6. More detailed analysis of all cases using a chromosome 6 tile‐path array confirmed the presence of overlapping regions of loss in only these two cases. One of these cases also showed trisomy chromosome 7. Monosomy of chromosome 8 was seen in a further two cases (17%), and a partial loss on chromosome 14 was observed in one additional case.

This is the first array‐based, genome‐wide study of SE. The observation that five of 12 cases examined (42%) at 0.97‐Mb resolution showed chromosomal copy number abnormalities is a novel finding in this tumor type.
A rapid flow cytometric technique for the detection of platelet‐monocyte complexes, activated platelets and platelet‐derived microparticles
Authors: PEARSON LAURA , THOM JIM , ADAMS MURRAY , OOSTRYCK ROBERT , KRUEGER ROM , YONG GERALD , BAKER ROSS
Published: April 2008

Platelet activation occurs in a variety of clinical situations in which it directly contributes to the pathology. This study reports a simple flow cytometric assay for platelet activation which measures platelet‐derived microparticles, activated platelets and platelet–monocyte complexes. Pre‐ and post analytical conditions were investigated and optimized and a normal range established on 20 healthy controls. Twenty patients pre‐ and post percutaneous coronary intervention (PCI) were tested with the technique. Soluble activation markers sCD40 ligand and sP‐selectin and plasma phospholipid levels were measured in both groups. There was a significant increase in activated platelets and platelet–monocyte complexes between normal and pre‐PCI (P = 0.005 and 0.0275, respectively) suggesting an activated state. There was a significant fall in activated platelets post‐PCI (P = 0.0027) which was mirrored by a fall in soluble CD40 ligand, soluble P‐selectin and plasma phospholipid levels (P = 0.0066, <0.0001 and 0.0032, respectively) consistent with antiplatelet therapy administered during the process. This is a reliable and rapid method for the assessment of ex vivo platelet activation which may be an aid in diagnosis and help guide therapy for patients with thrombotic disease.
The reactive oxygen‐driven tumor: relevance to melanoma
Authors: Fried Levi , Arbiser Jack L.
Published: April 2008

In melanoma, at least four major signaling abnormalities have been described. They include β‐catenin deregulation (mutation/mislocalization), p16 loss, MAP kinase activation, and Akt activation. In this review, we discuss the role of the fourth pathway, known as the reactive oxygen driven tumor. The role of reactive oxygen in tumorigenesis is likely to relate to virtually all forms of cancer, and lends itself to specific therapies. These include blockade of reactive oxygen, resulting in decreased activation of NF‐κB, which should sensitize tumors to chemotherapy and radiation. The phenotype of the reactive oxygen driven tumor can be monitored using available markers already in use in most hospital laboratories.
Intergeneric hybridization between Hordeum and Hordelymus (Poaceae)
Authors: von Bothmer Roland , Jacobsen Niels
Published: April 2008

Intergeneric hybridization between the monotypic Eurasian genus Hordelymus and species of Hordeum was performed. Hybrids were obtained in nine combinations and the meiotic pairing was analyzed in four combinations (6 families). Hordelymus europaeus is probably an alloploid with two different genomes. The very low pairing in the hybrids with H. jubatum, H. brachyantherum, and H. pusillum indicates that these species do not have any genomes in common with Hordelymus. The hybrids with H. depressum have an intermediate pairing which suggests that there is a certain homoeology in one genome.
Cytology and systematica of Araceae
Authors: Petersen Gitte
Published: April 2008

The chromosome numbers of 75 species belonging to the family Araceae have been determined. The numbers for 53 species are reported for the first time. One number differs from previous reports (Aglaodorum), and one number is corrected (Phymatarum). Within 15 genera (Gymnostachys, Pothoidium, Alloschemone, Heteropsis, Holochlamys, Anaphyllopsis, Dracontioides, Pseudohydrosme, Montrichardia, Bucephalandra, Taccarum, Asterostigma, Gorgonidium, Spathantheum and Ulearum) the chromosome numbers have not previously been determined. The total number of genera cytologically investigated is now 99 (c. 94%).

A great diversity in chromosome numbers as well as in chromosome size and constitution is found. The results are discussed in relation to the phylogeny and the previously published classifications of the family.

A total list of chromosome numbers counted (>700 species) in the Araceae is presented (Appendix).
A revision of Hyospathe (Arecaceae)
Authors: Skov Flemming , Balslev Henrik
Published: April 2008

The neotropical palm genus Hyospathe includes two species, H. elegans and H. macrorhachis. Based on morphological, anatomical and palynological evidence, most of the names previously published in the genus have been synonymized into H. elegans. A detailed treatment of the variation and distribution of this broadly defined and widespread species is given.
Rhynchospora modesti‐lucennoi, sp. nov. (Cyperaceae), from the western Mediterranean, Madagascar and Africa
Authors: Castroviejo Santiago
Published: April 2008

From the study of the material available, it is concluded that the western Mediterranean populations previously considered as Rhynchospora rugosa should be treated as a separate species, described here as R. modesti‐lucennoi.
The identity of Siderobombyx and a new species of Xanthophytum (Rubiaceae)
Authors: Tange Christian
Published: April 2008

The monotypic genus Sidernbombyx is reduced to Xanthophytum. A new species Xanthophytum bullatum from Borneo, Sarawak, Gunung Mulu National Park is described, the first species in the genus with bullate leaves. An overview of character states is given for the genus Xanthophytum. This covers aspects of vegetative, flower, fruit, seed and pollen morphology. It is shown that the genus Kajewskiellu is very close to Xanthophytum.
Parallel ecoclinal evolution and taxonomy of F'rankenia (Frankeniaceae) in the Cape Verde Islands, W Africa
Authors: Brochmann Christian , Lobin Wolfram , Sundingx Per , Stabbetorp Odd
Published: April 2008

One species, the Macaronesian and N African Frankenia ericifolia, with three subspecies is recognized in the Cape Verde Islands: ssp. ericifolia (a coastal, xerophytic ecotype), ssp. caboverdeana ssp. nov. (a coastal, mesophytic ecotype), and ssp. montana ssp. nov. (a montane, hygrophytic ecotype). Subspecies caboverdeana and ssp. montana are endemic to the Cape Verde Islands. In addition, ssp. latifolia comb. et stat. nov. is tentatively recognized as endemic to the Canary Islands. Reproductive data suggest that the Capeverdean plants are self‐compatible but mainly outcrossing. Mor‐phometric analyses of field‐collected material and progeny families cultivated under uniform conditions demonstrate that there is genetically based, clinal morphological variation connecting ssp. ericifolia and ssp. caboverdeana in several coastal areas that vary in humidity conditions because of varying exposures to the trade wind. Clinal variation was observed in leaf‐, calyx‐, petal‐, and seed characters, probably caused by one or a few genetic factors that control organ size and are subjected to differential selection with respect to drought tolerance. The variation in progeny families derived from morphologically intermediate parents was no higher than the variation in progeny families derived from parents belonging to the “pure” subspecies. It is thus likely that the clinal variation is caused by primary evolution along continuous humidity gradients rather than hybridization. The existence of similar ecoclines in different islands and the potentially simple genetic basis of such clinality suggest that ssp. caboverdeana has evolved several times in mesic environments from xerophytic, ericifolia‐like ancestors.
Light and electron microscopical observations on sperm cells of Guizotia abyssinica (Asteraceae)
Authors: Dagne Kifle , Heneen Waheeb K.
Published: April 2008

The sperm cells of Guizotia abyssinica were studied during pollen development by light microscopy and at anther dehiscence by transmission electron microscopy. During development, the nuclei change shape from spherical to elongate, thread‐like and banded. They are straight or folded, and rarely spiral‐shaped when present in the pollen tube. Electron microscopy disclosed that the elongated sperm nuclei are apparently lobate. Intermittently, they are constricted and attenuated or convoluted. The major part of the sperm chromatin is condensed and peripheral, while a minor part is dispersed and central. The scanty sperm cytoplasm contains mitochondria and starch granules. The cytoplasm is mainly restricted to spaces adjoining constricted, lobed and convoluting nuclear sites. Some cytoplasmic patches become embayed in the nucleus at these sites. The periplasm bordering the sperm cells may originate from lucid dilations of the lumen between the plasma membranes of the sperm and vegetative cells. The periplasm is sometimes partially or entirely surrounded by double‐membraned endoplasmic reticulum. Folded sperm cells with less coherent periplasm possibly represent a late stage preceding discharge into the pollen tube. The sperm cells always precede the vegetative nucleus into the pollen tube.
Notes on the ecology of Synurophycean algae found in Portugal
Authors: Calado A. J. , Craveiro S. C.
Published: April 2008

A survey of species of Synurophyceae in samples collected over the last ten years from freshwater bodies of central Portugal resulted in the identification of 33 taxa of Mallomonas and 6 of Synura, of which a total of 24 taxa are reported for the first time from Portugal by means of electron microscopy. A short ecological description is provided for the sampling sites and notes are added about the ecological preferences demonstrated by the most common taxa. Use is made of the saprobity system to designate different types of eutrophic waters. SEM micrographs are provided for all the taxa reported; SEM study was conducted in most cases on uncovered material at an acceleration tension of 2 kV, and higher tensions were used to view the internal structure of the scales and help solving some identification problems.
Vitamin D deficiency: a study of community beliefs among dark skinned and veiled people
Authors: BRAND Caroline A. , ABI Hodan Y. , COUCH Dianne E. , VINDIGNI Angela , WARK John D.
Published: April 2008

Aim:  Vitamin D is essential for musculoskeletal health. In addition to known high risk for older, housebound or institutionalized people, there are increasing reports of vitamin D deficiency in younger Australian populations, who are dark‐skinned and/or veiled. The aim of this study is to investigate socio‐cultural barriers and enablers to reducing risk of vitamin D deficiency among dark‐skinned and veiled community groups in a Melbourne metropolitan area.

Methods:  A qualitative exploratory study was undertaken by an acute and community care partnership group based in the City of Melbourne and City of Moonee Valley areas, Victoria, Australia. Community‐dwelling people 18 years or more who were dark‐skinned or veiled participated. A trained facilitator used semistructured questions to explore awareness of vitamin D deficiency, knowledge about risks and barriers to risk management. Discussion was summarized and dominant themes extracted.

Results:  There were gender differences in awareness of risk. Men were unaware or considered themselves not to be at risk of vitamin D deficiency. Cultural issues influenced access to, and sourcing of, health information. In particular, community opinion leaders and use of local media such as radio were considered important avenues for knowledge transfer in addition to health care providers. Relocation from community settings in Africa to the built environment of Melbourne was reported to inhibit safe, comfortable and culturally appropriate access to sun exposure. Access to, and sustained use of vitamin D supplementation was limited by financial constraints.

Conclusion:  A comprehensive health promotion response that includes health provider and community partnerships is required to meet the complex needs of these communities.
Amyloidosis: a rheumatological perspective on diagnosis, further investigation and treatment
Authors: LAM S. K. L. , NGIAN G. S. , TRAVERS R. , LIM K. K. T.
Published: April 2008

In this Grand Round, we present a 58‐year‐old man with a presumptive diagnosis of rheumatoid arthritis (RA) who was being managed by a plastic surgery unit for a dorsal swelling of his right hand. While awaiting surgery for this lesion, he sustained a pathological fracture of his left neck of femur. This necessitated a total hip joint replacement and pathology revealed amyloidosis. Excision of the hand swelling also revealed amyloidosis as the cause. We discuss the ways in which amyloidosis can mimic musculoskeletal disease as well as the importance and some potential pitfalls of further investigation and management once the diagnosis of amyloidosis has been made.