bluuebunny/crossref_metadata_2025_split huggingface dataset:
Degradation properties and ion release characteristics of Resilon® and phosphate glass/polycaprolactone composites
Authors: Borbely P. , Gulabivala K. , Knowles J. C. 
Published: November 2008

AbstractAims  To (i) characterise the degradation pattern and ion release characteristics of bioactive glass/polycaprolactone (PCL) composites; (ii) compare the degradation behaviour of composites containing phosphate glass to that of Resilon®; and (iii) determine the potential to control the degradation of the composites by modifying the iron content of phosphate glasses.Methodology  The degradation behaviour of the phosphate glass/PCL samples (n = 3) and that of Resilon® were determined in two aqueous solutions (buffered distilled water, Hanks Buffered Saline Solution) over a 7‐day period using weight change measurement, ion chromatography, light microscopy (LM) and scanning electron microscopy (SEM).Results  An initial increase in weight of the samples was followed by loss. All phosphate glass/PCL composites released various amounts of iron, sodium, calcium and phosphate ions into solution. The Resilon® samples released only sodium and calcium ions. The visual methods (LM, SEM) showed distinct precipitate (calcium phosphate) formation on the surface of the phosphate glass/PCL composites but only a faint surface residue on the surface of Resilon®.Conclusions  The degradation pattern of the composites containing phosphate glass was different from that of Resilon®. The phosphate glass/PCL composites encouraged precipitate formation on the material surface, which may be advantageous in creating a marginal and apical seal.
Effect of EDTA conditioning upon the retention of fibre posts luted with resin cements
Authors: Rasimick B. J. , Shah R. P. , Musikant B. L. , Deutsch A. S. 
Published: November 2008

AbstractAim  To determine if a final rinse with EDTA improves the short‐term in‐tooth retentive strength of adhesively luted fibre‐reinforced composite posts.Methodology  Six different commercial fibre post systems were tested. Post spaces in extracted human anterior teeth were irrigated with either 6% NaOCl or 6% NaOCl followed by 17% EDTA. Posts were luted using the manufacturer’s recommended bonding agent and luting cement. Two different sizes of post were tested for each post system. After 24 h of storage, the retentive strength of the post to the tooth (14 per group, 336 total) was tested using a pull‐out technique. Three‐way anova and the Student–Newman–Kuels test were used to test the effects of irrigation regimen, post size and post brand on the retentive strength of the fibre post.Results  Almost every sample failed at the interface between dentine and luting cement. Irrigation method did not have any significant effect (P > 0.14) for any group other than ParaPost Fibre White (P < 0.001). The overall retention of a post appeared to be correlated to the amount of surface texture on the post; the smooth ICEPost was the least retentive brand, the textured FibreKor and the ParaPost Fibre White posts were moderately retained, and the threaded Flexi‐Post Fibre and the Flexi‐Flange Fibre posts were the most retentive brands tested. For all brands, larger diameter posts were more retentive than smaller diameter posts (P < 0.008).Conclusions  A final rinse of EDTA did not improve the short‐term retention of fibre posts except for ParaPost Fibre White.
Influence of tooth age and root section on root dentine dye penetration
Authors: Thaler A. , Ebert J. , Petschelt A. , Pelka M. 
Published: November 2008

AbstractAim  To investigate dye permeability of root dentine according to patients’ age, root section and dye penetration time.Methodology  A total of 96 extracted human single‐rooted teeth, assigned to four age groups (<30, 30–45, 45–60 and >60 years) were separated at the cemento–enamel junction and root canals were enlarged. The root surfaces were coated with cyanocrylate to prevent external dye penetration and centrifuged in distilled water to eliminate air. For dye penetration the root canals were filled with methylene blue 5%. After 1, 30 and 60 days eight roots per age group were cross‐sectioned in 1 mm slices. Dye penetrated areas and the complete dentine areas were digitized and measured. Differences between groups were judged with anova and LSD, P < 0.05 or P < 0.01.Results  The root section, the patients’ age and the penetration time influenced significantly the penetrated areas (P < 0.05). After 1 and 30 days significant differences could be found only in the apical root sections between all age groups (P < 0.05). Dye penetration areas systematically decreased with increasing age and also from coronal to apical (P < 0.01).Conclusions  Age influenced dye penetration significantly. Dye penetration also depended on the location (coronal, middle and apical) within the root canal. These findings indicate that there may be a correlation between the tooth age and permeability of root dentine, which may influence the distribution and effectiveness of drugs used for root canal disinfection.
Cytotoxic effects of halogen‐ and light‐emitting diode‐cured compomers on human pulp fibroblasts
Authors: TUNÇ EMINE ŞEN , ÖZER LEVENT , SARI ŞAZIYE , ÇETINER SERAP 
Published: November 2008

Objective.  The aim of this study was to determine the cytotoxic effects of three different compomers (Dyract AP, Compoglass, and Hytac) cured using a halogen light‐curing unit (LCU) and a light‐emitting diode (LED) LCU on human pulp fibroblasts.Methods.  Specimens of three compomers were added to human pulp fibroblast cultures. Cytotoxicity was evaluated over 96 h using the agar overlay method.Results.  All three compomers tested were found to be moderately cytotoxic to human pulp fibroblasts, regardless of whether they were cured using halogen or LED LCUs. The decolorization zone of Hytac was significantly larger than those of the other compomers tested (P < 0.05). Dyract AP and Compoglass specimens showed greater decolorization when cured with LED than with halogen LCUs (P < 0.05).Conclusion.  Compomers are potentially toxic to human pulp fibroblasts, and the type of curing unit may affect compomer toxicity.
Zinc deficiency among the elderly attending a care centre in Sharpeville, South Africa
Authors: Oldewage‐Theron W. H. , Samuel F. O. , Venter C. S. 
Published: November 2008

AbstractBackground The elderly are particularly prone to zinc deficiency because of nutritional and physiological vulnerabilities associated with ageing. A low socio‐economic status may further increase the risk of zinc deficiency. This cross‐sectional descriptive study assessed the zinc status of an elderly sample in the Vaal region, South Africa.Methods The participants were 170 randomly selected elderly people attending a day care centre in Sharpeville. Twenty‐four‐hour recalls were administered for dietary intake. Weight and height were measured and venous blood samples (n = 67) were drawn to determine biochemical indices.Results The mean age of the respondents was 71.7 years. The mean ± SD daily dietary intake for zinc was 11.0 ± 6.12 mg. Approximately half of the subjects (51.5%) did not reach two‐thirds of the recommended dietary allowance for zinc. The mean serum zinc concentration was 61.8 ± 8.5 μg dL−1(9.4 ± 1.3 μmol L−1), with 76.3% of the subjects having zinc values less than the recommended values of 70 μg dL−1(10.7 μmol L−1). Maize meal was the staple in the diet of approximately half the study population. Although South African maize meal is now fortified with zinc oxide, maize also contains high concentrations of phytate, a known inhibitor of mineral bioavailability.Conclusions The results of the present study suggested that zinc deficiency existed in these elderly people. Further research is, however, needed to elucidate possible underlying factors so that appropriate intervention can be implemented.
Infectious aetiology of Hodgkin and non‐Hodgkin lymphomas: a review of the epidemiological evidence
Authors: Hjalgrim H. , Engels E. A. 
Published: November 2008

Abstract.Lymphomas constitute a heterogeneous group of malignant disorders with different clinical behaviours, pathological features and epidemiological characteristics. For some lymphoma subtypes, epidemiological evidence has long pointed to infectious aetiologies. A subset of Hodgkin lymphoma is strongly linked to Epstein–Barr virus (EBV) infection. In addition, infectious agents can directly infect and transform lymphocytes (e.g. EBV, human herpesvirus 8), induce immunosuppression (human immunodeficiency virus), or cause chronic immune stimulation (hepatitis C virus, Helicobacter pylori), all of which may play a role in the development of various non‐Hodgkin lymphoma subtypes. Here, we review the epidemiological evidence linking infections with malignant lymphoma.
Amplification of an alternate transporter gene suppresses the avirulent phenotype of glucose transporter null mutants in Leishmania mexicana
Authors: Feng Xiuhong , Rodriguez‐Contreras Dayana , Buffalo Cosmo , Bouwer H. G. Archie , Kruvand Elizabeth , Beverley Stephen M. , Landfear Scott M. 
Published: November 2008

SummaryA glucose transporter null mutant of the parasitic protozoan Leishmania mexicana, in which three linked glucose transporter genes have been deleted by targeted gene replacement, is unable to replicate as amastigote forms within phagolysomes of mammalian host macrophages and is avirulent. Spontaneous suppressors of the null mutant have been isolated that partially restore replication of parasites within macrophages. These suppressor mutants have amplified the gene for an alternative hexose transporter, the LmGT4 permease (previously called the D2 permease), on a circular extrachromosomal element, and they overexpress LmGT4 mRNA and protein. The suppressors have also regained the ability to transport hexoses, and they have reverted other phenotypes of the null mutant exhibiting enhanced resistance to oxidative killing, heat shock and starvation for nutrients, as well as augmented levels of the storage carbohydrate β‐mannan, increased cell size and increased growth as insect stage promastigotes compared with the unsuppressed mutant. Complementation of the null mutant with the LmGT4 gene on a multicopy episomal expression vector also reverted these phenotypes, confirming that suppression results from amplification of the LmGT4 gene. These results underscore the importance of hexose transporters for the infectious stage of the parasite life cycle.
MxiC is secreted by and controls the substrate specificity of the Shigella flexneri type III secretion apparatus
Authors: Botteaux Anne , Sory Marie Paule , Biskri Latéfa , Parsot Claude , Allaoui Abdelmounaaïm 
Published: November 2008

SummaryMany Gram‐negative pathogenic bacteria use a type III secretion (T3S) system to interact with cells of their hosts. Mechanisms controlling the hierarchical addressing of needle subunits, translocators and effectors to the T3S apparatus (T3SA) are still poorly understood. We investigated the function of MxiC, the member of the YopN/InvE/SepL family in the Shigella flexneri T3S system. Inactivation of mxiC led specifically to a deregulated secretion of effectors (including IpaA, IpgD, IcsB, IpgB2, OspD1 and IpaHs), but not of translocators (IpaB and IpaC) and proteins controlling the T3SA structure or activity (Spa32 and IpaD). Expression of effector‐encoding genes controlled by the activity of the T3SA and the transcription activator MxiE was increased in the mxiC mutant, as a consequence of the increased secretion of the MxiE anti‐activator OspD1. MxiC is a T3SA substrate and its ability to be secreted is required for its function. By using co‐purification assays, we found that MxiC can associate with the Spa47 ATPase, which suggests that MxiC might prevent secretion of effectors by blocking the T3SA from the inside. Although with a 10‐fold reduced efficiency compared with the wild‐type strain, the mxiC mutant was still able to enter epithelial cells.
Major histocompatibility complex class I chain‐related gene A polymorphism and linkage disequilibrium with HLA‐B alleles in Euro‐Brazilians
Authors: Ribas F. , Oliveira L. A. , Petzl‐Erler M. L. , Bicalho M. G. 
Published: November 2008

AbstractMajor histocompatibility complex class I chain‐related gene A (MICA) was identified within the human leukocyte antigen (HLA) class I region and was located 46 kb centromeric from HLA‐B locus. It functions as a ligand for human γδ T, CD8 T and natural killer (NK) cells by binding the NKG2D receptor. The aims of the present study were to determine the distribution of MICA alleles and MICA–HLA‐B haplotypes in a sample of Euro‐Brazilians. Through the combination of three typing methods, polymerase chain reaction (PCR)–sequence‐specific oligonucleotide probe, PCR–sequence‐specific primer and PCR–restriction fragment length polymorphism, 19 alleles were detected besides a MICA gene deletion in a sample composed by 204 unrelated Euro‐Brazilians. The most commonly observed alleles were: MICA*00801 (25.3%), MICA*00201 (17.7%) and MICA*00901 (13.7%). The GCT repeat polymorphism variant A6 was the most commonly found. The most frequent haplotype found in this study was MICA*00901‐B*51 (8.1%), followed by haplotypes MICA*00201‐B*35 (6.1%) and MICA*00801‐B*07 (6.1%). MICA*00801 truncated product, and its low affinity for NKG2D receptor may work as an inhibitor in its putative soluble form. It may also be that selective forces may favor MICA*00801 heterozygosity with NKG2D high affinity MICA alleles enabling activation and inhibition of cytotoxic activity of cells expressing the NKG2D receptor. The possibility of selective neutrality or of balancing selection still provides no explanation for MICA gene polymorphisms. Is it maintained by genetic drift or by the influence of migratory waves? Are there favored alleles while others present the same adaptive value?
Vascular endothelial growth factor gene polymorphisms and serum levels in Behçet’s disease
Authors: Kamoun M. , Houman M. H. , Hamzaoui A. , Hamzaoui K. 
Published: November 2008

AbstractVascular endothelial growth factor (VEGF) is important for angiogenesis and inflammation, both of which are codependent and contribute to the pathophysiology of Behçet’s disease (BD). In this report, we sought to investigate whether the selected VEGF polymorphisms [−634 C/G, +936 C/T and an 18 bp insertion/deletion (I/D) at −2549 of the VEGF promoter region] are associated with susceptibility and severity of BD in the Tunisian population. One hundred and thirty‐five Tunisian BD patients and 157 healthy controls were recruited. The VEGF gene was genotyped by polymerase chain reaction followed by digestion with restriction endonucleases. VEGF serum levels of BD patients and healthy controls were measured by enzyme‐linked immunosorbent assay. We found no association between the VEGF polymorphisms and the susceptibility to BD. However, when data were analysed according to the presence of each symptom, we found a positive association between VEGF 18 bp I/D polymorphism and ocular involvement as well as BD severity. Indeed, among the BD patients, the frequency of the 18 bp I/I genotype was less in patients with ocular inflammation (6.1% vs 24.6%, P = 0.007) and in patients with severe BD (9.2% vs 21.4%, P = 0.0014). Moreover, the mean serum VEGF level was considerably higher in BD patients (P < 0.01) than in healthy controls. We suggest that VEGF gene polymorphisms may be involved in the development of the ocular BD as well as the severity of the disease.
Polymorphic insertions in 5 Alu loci within the major histocompatibility complex class I region and their linkage disequilibria with HLA alleles in four distinct populations in mainland China
Authors: Tian W. , Wang F. , Cai J. H. , Li L. X. 
Published: November 2008

AbstractIn this study, we investigated the five polymorphic Alu loci located within human major histocompatibility complex (MHC) class I region in 445 individuals from four distinct Chinese populations: Hunan Han, Inner Mongolia Han, Inner Mongolia Mongol and Guangdong Han populations, with an emphasis on the linkage disequilibrium (LD) between Alu insertions and human leukocyte antigen (HLA)‐A, Cw and B loci in a southern (Hunan Province) and a northern (Inner Mongolia Autonomous Region) Chinese Han population. Our data showed that (a) the allele and haplotype frequencies of Alu and HLA‐A loci did not differ significantly between the two southern Chinese Han populations and showed remarkable homogeneity in the two northern Chinese populations; (b) AluyHG had the highest insertion rate and HLA‐A*02 harboring the single AluyHG insertion was most frequent among Alu insertion‐bearing haplotypes in all four populations; (c) haplotypes AluyHF insertion–HLA‐A*26, AluyHG insertion–HLA‐A*02 and AluyHJ insertion–HLA‐A*24 were in significant LD across the four groups and (d) haplotype AluyMICB insertion–HLA‐Cw*06 was in significant LD in both populations, while significant LD of haplotypes AluyMICB insertion–HLA‐B*54 and AluyMICB insertion–HLA‐B*48 was only observed in the Hunan Han population and the Inner Mongolia Han population, respectively. Haplotype HLA‐B*48‐MICA gene deletion–AluyMICB insertion was observed at a frequency of about 3.85% in the latter population. Our data, together with previous reports on several Asian‐Oceanian populations suggest the identity by descent of several common HLA‐A allelic lineages in these modern human populations. The novel population‐specific LD patterns uncovered in this study also shed new insight into HLA evolution and haplotype origin.
Decompositions of Price’s formula in an inhomogeneous population structure
Authors: TAYLOR P. 
Published: November 2008

AbstractThe central tool for the study of allele frequency change due to selection is the remarkably simple but powerful formula of Price [Nature227 (1970) 520]. Here, I provide what might be called a structural analysis of this formula. The formula essentially accumulates the average allele frequency change over many instances of a fitness‐determining interaction, but there are different ways of organizing this average and these lead to quite different computational algorithms. I present three of these: an analysis by population state, an analysis by recipient and an analysis by actor. A comparison of these can lead to a heightened understanding of the different factors behind selective allele frequency change. In particular, I pay attention to the effects of structural inhomogeneity on reproductive value (RV) and emphasize that Price’s formula measures RV‐weighted allele frequency change. I examine in detail a simple example as a crucial way of cementing the different theoretical pathways. My aim was to produce a simple transparent presentation and therefore I work with a simple population structure and have omitted a number of technical details that are found elsewhere.
Natural selection maximizes Fisher information
Authors: FRANK S. A. 
Published: November 2008

AbstractIn biology, information flows from the environment to the genome by the process of natural selection. However, it has not been clear precisely what sort of information metric properly describes natural selection. Here, I show that Fisher information arises as the intrinsic metric of natural selection and evolutionary dynamics. Maximizing the amount of Fisher information about the environment captured by the population leads to Fisher's fundamental theorem of natural selection, the most profound statement about how natural selection influences evolutionary dynamics. I also show a relation between Fisher information and Shannon information (entropy) that may help to unify the correspondence between information and dynamics. Finally, I discuss possible connections between the fundamental role of Fisher information in statistics, biology and other fields of science.
Mating Effort and Cryptic Sperm Choice in Scorpionflies: Male Investment Strategy vs. Female Control
Authors: Vermeulen Andreas , Engels Sierk , Sauer Klaus P. 
Published: November 2008

AbstractIn this study, we examined which sex controls sperm transfer during copulation in scorpionflies. Therefore male scorpionflies were doubly mated to females of high and low fecundity to explore whether they allocate sperm according to female quality. While mating order had no effect males transferred sperm at higher rates when mating with low‐quality instead of high‐quality females. As there is no obvious benefit from providing low‐fecundity females with more sperm, we suggest a condition‐dependent female ability to counteract sperm transfer. Therefore, we disabled females at the beginning of copulations using the insecticide Propoxur which leads to total paralysis caused by tremors. While the provoked muscle contractions led to significantly smaller numbers of sperm transferred, Propoxur treatment had no effect on males. We suggest female counteracting of sperm transfer to be adaptive by decreasing the relative amount of sperm transferred by low‐quality males and increasing the proportion of offspring sired by high‐quality males.
The Use and Transfer of Information About Predation Risk in Flocks of Wintering Finches
Authors: Roth II Timothy C. , Cox Jonathan G. , Lima Steven L. 
Published: November 2008

AbstractSeveral studies in behavior have focused in some way on how groups of prey gather and use information about predation risk. Although asymmetries in information about risk exist among members of real groups, we know little about how such uneven information might affect individual or group antipredator decisions. Hence, we studied the use and transfer of information about the risk of predation in small flocks of wintering birds. House finches (Carpodacus mexicanus; 28 groups of three) were held in large enclosures divided into safe and risky patches. We controlled the information about risk available to each individual by conducting attacks with a model hawk that was visible to only a single (informed) bird. Repeated attacks on a single individual did not reduce the amount of feeding by other birds in that patch, although the time to resume feeding after observing a response to an attack event was somewhat longer than after a no attack event. These results suggest that informed individuals impart some information to naïve (uninformed) birds, but this effect was not strong. In fact, the frequent return of informed individuals to feeders after observing uninformed individuals feed suggests that finches relied more on public information regarding safety than their own personal information in deciding when to feed. Group patch choice appeared to be based on a majority‐rules decision, although an effect of dominance status was apparent. Our results suggest that subordinate flock members may exert a large influence over group decision‐making by acting as spatial ‘anchors’.