bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of anaerobic toluene and hydrocarbon degraders in contaminated aquifers using benzylsuccinate synthase (bssA) genes as a functional marker
Authors: Winderl Christian , Schaefer Sabine , Lueders Tillmann 
Published: January 2007

SummaryBenzylsuccinate synthase (Bss) is the key enzyme of anaerobic toluene degradation and has been found in all anaerobic toluene degrading bacterial isolates tested. However, only a few pure cultures capable of anaerobic toluene oxidation are available to date, and it is important to understand the relevance of these model organisms for in situ bioremediation of hydrocarbon‐contaminated aquifers. Due to their phylogenetic dispersal, it is not possible to specifically target anaerobic toluene degraders using marker rRNA genes. We therefore established an assay targeting a ∼794 bp fragment within the Bss alpha‐subunit (bssA) gene, which allows for the specific detection and affiliation of both known and unknown anaerobic degraders. Three distinct tar‐oil‐contaminated aquifer sites were screened for intrinsic bssA gene pools in order to identify and compare the diversity of hydrocarbon degraders present at these selected sites. We were able to show that local diversity patterns of degraders were entirely distinct, apparently highly specialized and well‐adapted to local biogeochemical settings. Discovered at one of the sites were bssA genes closely related to that of Geobacter spp., which provides evidence for an importance of iron reduction for toluene degradation in these sediments. Retrieved from the other two sites, dominated by sulfate reduction, were previously unidentified bssA genes and also deeply branching putative bssA homologues. We provide evidence for a previously unrecognized diversity of anaerobic toluene degraders and also of other hydrocarbon degraders using fumarate‐adding key reactions in contaminated aquifers. These findings enhance our current understanding of intrinsic hydrocarbon‐degrading microbial communities in perturbed aquifers and may have potential for the future assessment and prediction of natural attenuation based on degradation genes.
Molecular and morphological characterization of the association between bacterial endosymbionts and the marine nematode Astomonema sp. from the Bahamas
Authors: Musat Niculina , Giere Olav , Gieseke Armin , Thiermann Frank , Amann Rudolf , Dubilier Nicole 
Published: January 2007

SummaryMarine nematode worms without a mouth or functional gut are found worldwide in intertidal sandflats, deep‐sea muds and methane‐rich pock marks, and morphological studies show that they are associated with endosymbiotic bacteria. While it has been hypothesized that the symbionts are chemoautotrophic sulfur oxidizers, to date nothing is known about the phylogeny or function of endosymbionts from marine nematodes. In this study, we characterized the association between bacterial endosymbionts and the marine nematode Astomonema sp. from coral reef sediments in the Bahamas. Phylogenetic analysis of the host based on its 18S rRNA gene showed that Astomonema sp. is most closely related to non‐symbiotic nematodes of the families Linhomoeidae and Axonolaimidae and is not closely related to marine stilbonematinid nematodes with ectosymbiotic sulfur‐oxidizing bacteria. In contrast, phylogenetic analyses of the symbionts of Astomonema sp. using comparative 16S rRNA gene sequence analysis revealed that these are closely related to the stilbonematinid ectosymbionts (95–96% sequence similarity) as well as to the sulfur‐oxidizing endosymbionts from gutless marine oligochaetes. The closest free‐living relatives of these gammaproteobacterial symbionts are sulfur‐oxidizing bacteria from the family Chromatiaceae. Transmission electron microscopy and fluorescence in situ hybridization showed that the bacterial symbionts completely fill the gut lumen of Astomonema sp., suggesting that these are their main source of nutrition. The close phylogenetic relationship of the Astomonema sp. symbionts to known sulfur‐oxidizing bacteria as well as the presence of the aprA gene, typically found in sulfur‐oxidizing bacteria, indicates that the Astomonema sp. symbionts use reduced sulfur compounds as an energy source to provide their hosts with nutrition.
Urethral replacement using epidermal cell‐seeded tubular acellular bladder collagen matrix
Authors: Fu Qiang , Deng Chen‐liang , Liu Wei , Cao Yi‐lin 
Published: January 2007

OBJECTIVESTo investigate the feasibility of replacing urinary epithelium cells with foreskin epidermal cells to reconstruct engineered anterior urethra with an acellular collagen matrix.MATERIALS AND METHODSAcellular collagen matrices were generated from allogeneic rabbit bladder submucosa. In nine rabbits, autologous foreskin epidermal cells were isolated, expanded in vitro, and labelled with 5‐bromo2’‐deoxy‐uridine (BrdU) before seeding onto a tubular acellular collagen matrix (1.5 × 1 cm). In male rabbits, a urethral mucosal defect was created, and urethroplasty performed with a tubular acellular collagen matrix seeded with epidermal cells (nine rabbits) or with a matrix with no cell seeding (nine rabbits; control group). Urethrography was done at 1, 2 and 6 months after grafting. The urethral grafts were harvested and analysed grossly and histologically.RESULTSIn the control group, gross views and urethrography revealed stricture of repaired defects at the different sample times. In the experimental group, a wide urethral calibre was maintained with no sign of strictures. Histology in the control group showed a single layer of epithelium cells with disorganized muscle fibre bundles in the submucosa layer at 1 month after grafting, and a transitional cell layer surrounded by disorganized muscle fibre bundles at 2 and at 6 months. Grafts seeded with epidermal cells formed a single‐layer structure by 1 month, and at 2 and 6 months there were several layers of epidermal cells with abundant vessels in the submucosa. There was an evident margin between graft epidermal cells and host epithelium at 6 months. The implanted cells expressed keratin, shown by staining with anti‐pancytokeratins. Immunofluorescence for BrdU confirmed the presence of implanted epidermal cells at 1 month after grafting; there were fewer positive cells at the implantation site at 2 months. At 6 months, there were several layers of epidermal cells with no signs of BrdU staining.CONCLUSIONSUrethral reconstruction was better with an acellular collagen matrix seeded with epidermal cells than with the acellular collagen matrix alone. Foreskin epidermal cells seem adequate in replacing urethral epithelium cells for urethral reconstruction.
Functional heterogeneity of prostatic intraepithelial neoplasia: the duration of hormonal therapy influences the response
Authors: Kang Tyler Y. , Nichols Peter , Skinner Eila , Groshen Susan , Valin Greg , Ye Wei , Raghavan Derek 
Published: January 2007

OBJECTIVESTo use a clinical model of androgen‐deprivation therapy (ADT) followed by radical prostatectomy (RP) to test the hypothesis that prostatic intraepithelial neoplasia (PIN, a premalignant lesion of the prostate causally linked to prostate cancer) is heterogeneous for hormone responsiveness, which might explain aspects of the heterogeneity of the natural history of prostate cancer, for although ADT has been used to reduce prostate cancer, there are controversial data on the effect of ADT on PIN.PATIENTS AND METHODSWe assessed retrospectively patients with biopsy‐confirmed prostate cancer who had RP; some patients had received ≥3 months of ADT at the discretion of their surgeons, and patients from the same cohort who did not have ADT were used as controls. Patients were sequentially selected from the database and their pathology slides were reviewed by a pathologist unaware of the initial presence of PIN (assessed by an independent observer). Fisher’s exact test was used to compare the proportions of patients who had residual PIN in the study and control groups. Exact logistic regression was used to evaluate the duration of ADT on PIN regression.RESULTSEighteen patients initially diagnosed with PIN who had no ADT were identified, and 28 with PIN who had ADT were also assessed. All patients who had had no ADT had residual PIN, whereas seven of 28 receiving ADT had no residual PIN (P = 0.043). The evaluation of ADT between responders and nonresponders showed a statistically significant association between PIN regression and the duration of ADT (P <0.001). However, the response of PIN to ADT was not uniform, as 16% of patients on ADT for >6 months had residual PIN, suggesting variable sensitivity of PIN to ADT.CONCLUSIONThese results show that ADT causes PIN to regress, and that there is heterogeneity in this effect with the duration of ADT. We propose future prospective, multicentre, randomized trials in which the effect of ADT on PIN is characterized further.
Market Integration and Economic Development: A Long‐run Comparison
Authors: Keller Wolfgang , Shiue Carol H. 
Published: January 2007

AbstractHow much of China’s recent economic performance can be attributed to market‐oriented reforms introduced in the last two decades? A long‐run perspective may be important for understanding the process of economic development occurring today. This paper compares the integration of rice markets in China today and 270 years ago. In the eighteenth century, transport technology was non‐mechanized, but markets were close to being free. We distinguish local harvest and weather from aggregate sources of price variation in a historical sample and in a similarly constructed contemporary sample. Findings indicate the degree of market integration in the 1720s is a very good predictor of per capita income in the 1990s. Moreover, the current pattern of interregional income in China is strongly linked to persistent geographic factors that were already apparent several centuries ago, well before the enactment of modern reform programs.
Endogenous Growth, Taxes and Government Spending: Theory and Evidence*
Authors: Denaux Zulal S. 
Published: January 2007

AbstractThis paper provides a theoretical and empirical investigation of the simultaneous effects of taxes and government spending on long‐run economic growth in an endogenous growth framework. A two‐sector model is considered: one sector produces physical output and the other produces human capital. Government expenditure is divided into several categories, and several types of taxes are included. The property tax is especially interesting because it is a major source of revenue for local government. The theoretical model is estimated using annual panel data from North Carolina counties. This study finds that state‐level fiscal policies affect economic growth but county‐level fiscal policies do not.
R&D Policies and Endogenous Growth: A Dynamic General Equilibrium Analysis of the Case for Canada*
Authors: Ghosh Madanmohan 
Published: January 2007

AbstractThis paper utilizes a general equilibrium R&D model of endogenous growth via increasing capital variety to examine the impact of alternative policies on productivity and economic growth. The model is calibrated using data from the Canadian economy. Findings reveal that direct incentives such as subsidies to R&D activities would have the highest productivity impact on the Canadian economy, that an increase in subsidies to the users of R&D capital (output) would have a positive but smaller impact, and trade liberalization would have minimal effects on productivity growth via its impact on international R&D spillovers.
Fiscal Transfers and Distributive Conflict in a Simple Endogenous Growth Model with Unemployment
Authors: Bonatti Luigi 
Published: January 2007

AbstractIn the simplified formal treatment proposed in this paper, a decrease in a policy parameter - the ratio of total tax revenues to GDP - can monotonically increase long-term growth rate and may lead to a higher employment level. This notwithstanding, the paper shows that the redistributive implications of such a decrease may induce the wage earners to oppose it. As a consequence, policy-makers reflecting social preferences may undertake redistributive transfers generating persistent unemployment and lowering growth even if commitment technologies allowing them to follow preannounced tax policies were feasible.
Knowledge Capital and Venture Capital Investments: New Evidence from European Panel Data
Authors: Schertler Andrea 
Published: January 2007

AbstractCountries with a high amount of knowledge capital are likely to have higher volumes of venture capital (VC) investments because more researchers come up with innovative business ideas that require venture capital finance. Using panel data techniques, the paper finds evidence that VC investments depend strongly on the countries’ knowledge capital measured by the number of patents, or the number of R&D researchers, or gross domestic expenditures on R&D. In addition, the paper analyzes whether government-financed knowledge capital fulfills a special role for VC investments. It finds only weak evidence that VC investments depend, with a delay of several years, on government-financed knowledge capital.
Union density and determinants of union membership in 18 EU countries: evidence from micro data, 2002/031
Authors: Schnabel Claus , Wagner Joachim 
Published: January 2007

ABSTRACTUsing representative individual‐level data from the first round of the European Social Survey fielded in 2002/03, this article provides an empirical analysis of unionisation in 18 countries of the EU. We show that union density varies considerably in Europe, ranging from 84 per cent in Denmark to 11 per cent in Portugal. Estimating identical models for each country, we find that individuals’ probability of union membership is significantly affected by their personal characteristics, their attitudes and the characteristics of their workplace, whereas social factors seem to play a minor role. The presence of a union at the workplace and employees’ attitudes concerning strong unions are the two variables most strongly associated with unionisation.
The de‐collectivisation of pay setting in Britain 1990–98: incidence, determinants and impact
Authors: Charlwood Andy 
Published: January 2007

ABSTRACTWhat were the causes and consequences of declining collective bargaining coverage in Britain? The demise of collective bargaining did not lead to a greater use of individualised payment mechanisms, ‘high‐involvement’ practices or productivity gains. Wage inequality rose as a result of the decline. However, workplaces that abandoned bargaining created more jobs. Overall, these results raise questions about Britain’s labour market performance during the 1990s because they suggest that falling unemployment as a result of weaker trade unions came at the price of slower productivity growth and widening male wage inequality.
Explaining union membership of temporary workers in Spain: the role of local representatives and workers’ participative potential
Authors: Sánchez David Llorente 
Published: January 2007

ABSTRACTIt has been widely assumed that type‐of‐contract segmentation represents a strong structural constraint on trade union growth. The analysis of a sample of the Spanish workforce shows, however, that the effect of contract type on union membership is not statistically significant once the availability and performance of local union representatives are introduced in the explanatory model. Additionally, the worker’s participative potential, as indicated by his/her social and political capital, is also found to be a major explanatory factor. These findings are placed in comparative perspective and discussed in relation to possible union revitalisation strategies.
The Missing ApoE Allele
Authors: Seripa D. , Matera M. G. , Daniele A. , Bizzarro A. , Rinaldi M. , Gravina C. , Bisceglia L. , Corbo R. M. , Panza F. , Solfrizzi V. , Fazio V. M. , Forno G. Dal , Masullo C. , Dallapiccola B. , Pilotto A. 
Published: January 2007

SummaryThe human apoE gene (APOE, GenBank accession AF261279) shows a common polymorphism, with the three ɛ2, ɛ3 and ɛ4 alleles resulting from the haplotypes of two C→T SNPs. However, whereas the three common T‐T, T‐C and C‐C haplotypes corresponding to the ɛ2, ɛ3 and ɛ4 alleles are well known, the last C‐T haplotype (GenBank accession AY077451), encoding a fourth apoE allele, has rarely been reported. We detected this fourth allele in a Caucasian patient with motor neuron disease (MND). According to the literature we refer to this allele as ɛ3r. Although several explanations may be proposed for its formation, the existence of this fourth allele is consistent with the evolutionary hypothesis generally accepted for the apoE alleles. The rarity and physiological role of ɛ3r remains to be explained, and requires further investigation.
Developmental course of psychopathology in youths with and without intellectual disabilities
Authors: De Ruiter Karen P. , Dekker Marielle C. , Verhulst Frank C. , Koot Hans M. 
Published: January 2007

Background:  We aimed to describe similarities and differences in the developmental course of psychopathology between children with and without intellectual disabilities (ID).Methods:  Multilevel growth curve analysis was used to analyse the developmental course of psychopathology, using the Child Behavior Checklist (CBCL), in two longitudinal multiple‐birth‐cohort samples of 6‐ to 18‐year‐old children with ID (N = 978) and without ID (N = 2,047) using three repeated measurements across a 6‐year period.Results:  Children with ID showed a higher level of problem behaviours across all ages compared to children without ID. A significant difference between the samples in the developmental courses was found for Aggressive Behaviour and Attention Problems, where children with ID showed a significantly larger decrease. Gender differences in the development of psychopathology were similar in both samples, except for Social Problems where males with ID showed a larger decrease in problem behaviour across time than females with ID and males and females without ID.Conclusions:  Results indicate that children with ID continue to show a greater risk for psychopathology compared to typically developing children, although this higher risk is less pronounced at age 18 than it is at age 6 for Aggressive Behaviour. Contrary to our expectations, the developmental course of psychopathology in children with ID was quite similar from age 6 to 18 compared to children without ID. The normative developmental trajectories of psychopathology in children with ID, presented here, can serve as a yardstick against which development of childhood psychopathology can be detected as deviant.
Children's skin conductance reactivity as a mechanism of risk in the context of parental depressive symptoms
Authors: Cummings E. Mark , El‐Sheikh Mona , Kouros Chrystyna D. , Keller Peggy S. 
Published: January 2007

Background:  Children's physiological reactivity was examined as a moderator of relations between parental dysphoria and child adjustment problems, addressing gaps in the study of child characteristics as risk processes.Method:  One hundred fifty‐seven children (86 boys, 71 girls) were assessed twice over a two‐year interval. Skin conductance level reactivity (SCLR) to inter‐adult argument and problem‐solving tasks was observed.Results:  SCLR moderated longitudinal predictions of children's internalizing, externalizing and social adjustment problems, especially for paternal rather than maternal dysphoria. Higher SCLR predicted greater vulnerability to parental depressive symptomatology.Conclusions:  Findings highlight that individual differences in children's physiological reactivity may relate to risk for adjustment problems in the context of parental depressive symptoms.
Pacific Islands Families Study: behavioral problems among two‐year‐old Pacific children living in New Zealand
Authors: Paterson Janis , Carter Sarnia , Gao Wanzhen , Perese Lana 
Published: January 2007

Background:  The aim of this study was to determine (1) the prevalence of behavioral problems among two‐year‐old Pacific children living in New Zealand, (2) ethnic differences in behavioral problems, and (3) relationships between maternal and socio‐demographic variables and problem child behavior.Methods:  Data were gathered from the Pacific Islands Families (PIF) Study. Mothers of a cohort of 1398 Pacific infants born in Auckland, New Zealand during 2000 were interviewed when the children were two years of age. Maternal reports (1028) of child behavior were obtained using the Child Behavior Checklist (CBCL).Results:  In the PIF cohort, 15.6% of children were in the clinical range with one or more deviant scores from the seven syndrome scales, and 14% were in the borderline range. The prevalence rate of internalizing problems was 17.1% in the clinical range and 8.9% in the borderline range. The prevalence rate of externalizing problems was 6.6% in the clinical range and 13.7% in the borderline range. The prevalence rate of total problems was 14.2% in the clinical range and 9.6% in the borderline range. Discipline and maternal education were significantly associated with elevated externalizing scores. Household size, maternal education, cultural orientation, and number of years living in New Zealand were significantly associated with internalizing scores. Child ethnicity was significantly associated with internalizing, externalizing and total problem behavior scores. In the clinical range, child ethnicity and gender were significantly associated with the prevalence of problem behavior.Conclusions:  Cross‐ethnicity differences in CBCL scores were found, which illustrates the diversity in the Pacific population in New Zealand. Such findings highlight the way in which preschool behavior problems may vary within specific cultural settings and underscore the need for in‐depth research to explore these unique contexts.
Autistic traits in a population‐based ADHD twin sample
Authors: Reiersen Angela M. , Constantino John N. , Volk Heather E. , Todd Richard D. 
Published: January 2007

Background:  Most diagnostic nomenclatures do not allow for the concurrent diagnosis of autism and attention‐deficit/hyperactivity disorder (ADHD). Clinic‐based studies suggest autistic symptoms are common in children with ADHD, but such studies are prone to referral bias. This study assesses whether children with ADHD selected from the general twin population have elevated levels of autistic traits.Methods:  Nine hundred forty‐six twins identified by Missouri birth records were assigned to DSM‐IV ADHD diagnoses and seven population‐derived ADHD subtypes defined through latent class analysis of DSM‐IV ADHD symptoms. The Social Responsiveness Scale (SRS) was used as a quantitative measure of autistic traits. Linear regression was used to evaluate whether mean SRS scores differed between ADHD diagnostic groups.Results:  Mean SRS scores for DSM‐IV predominantly inattentive subtype and combined subtype ADHD groups were significantly higher than for subjects without DSM‐IV ADHD (p < .001, both comparisons). Five of the population‐derived ADHD subtypes (talkative‐impulsive, mild and severe inattentive, mild and severe combined) had significantly higher mean SRS scores compared to the latent class subtype with few ADHD symptoms (p < .001, all comparisons). DSM‐IV combined subtype and the population‐derived severe combined subtype had the highest mean total SRS scores and the highest mean scores for each of the three autism symptom domains, with a substantial proportion of individuals scoring in the clinically significant range.Conclusions:  This study provides population‐based evidence for clinically significant elevations of autistic traits in children meeting diagnostic criteria for ADHD. These results have implications for the design and interpretation of studies of both disorders.