bluuebunny/crossref_metadata_2025 huggingface dataset:
Arsenite oxidation by a chemoautotrophic moderately acidophilic Thiomonas sp.: from the strain isolation to the gene study
Authors: Duquesne Katia , Lieutaud Aurélie , Ratouchniak Jeanine , Muller Daniel , Lett Marie‐Claire , Bonnefoy Violaine
Published: September 2007

An autotrophic bacterium able to gain energy from the oxidation of arsenite was isolated from arsenite‐containing acid mine drainage waters. It belongs to the genus Thiomonas as shown by DNA–DNA hybridization experiments, 16S rRNA gene sequence, quinone and fatty acid content analyses. Carboxysomes were observed and the cbbSL genes encoding the ribulose 1,5‐bisphosphate carboxylase/oxygenase were detected, confirming that this bacterium is able to fix CO2. Arsenite oxidation was catalysed by a membrane‐bound enzyme, and this activity was detected essentially in cells grown in the presence of arsenite. The genes encoding the two subunits of the arsenite oxidase of the Thiomonas isolate have been sequenced. The small subunit has a characteristic Tat signal sequence and contains the residues binding the [2Fe‐2S] Rieske‐type cluster. The large subunit has the [3Fe‐4S] cluster‐binding motif as well as the residues proposed to bind arsenite. In addition, most of the residues interacting with the molybdenum cofactor are conserved. The genes encoding both subunits belong to an operon, likely with a gene encoding a cytochrome c. The expression of this operon is greater in cells grown in the presence than in the absence of arsenite, in agreement with a transcriptional regulation in the presence of this metalloid.
Approaches to integrating paediatric diabetes care and structured education: experiences from the Families, Adolescents, and Children's Teamwork Study (FACTS)
Authors: Murphy H. R. , Wadham C. , Rayman G. , Skinner T. C.
Published: September 2007

Aims  The Families, Adolescents and Children's Teamwork Study (FACTS) is a family‐centred structured education programme for children and adolescents with Type 1 diabetes. It aims to integrate group‐based diabetes education into routine care, enhance parental responsibility for self management and improve glycaemic control.

Methods  A randomized wait‐list control group study allocated participants to either the immediate (four educational sessions during year 1) or delayed intervention (four educational sessions during year 2). In both groups, glycated haemoglobin (HbA1c) was measured 3‐monthly and participants completed the Paediatric Quality of Life Inventory (PedsQL), Problem Areas in Diabetes Scale (PAID) and Diabetes Family Responsibility Questionnaire (DFRQ) before and after the intervention.

Results  Intention‐to‐treat analysis showed no significant difference in HbA1c or parental responsibility between participants randomized to the immediate or delayed programme. However, during 12 months’ follow‐up, families who attended ≥ 2 sessions reported increased parental involvement (P = 0.01), and in children/adolescents who attended ≥ 2 sessions HbA1c fell by 0.29% compared with an increase of 0.11% in non‐attenders (P = 0.04).

Conclusion  This family‐centred education programme has been integrated into paediatric diabetes care with potential benefits on parental involvement and glycaemic control, but further study is warranted before routine application into clinical care.
Gastric bypass alters the dynamics and metabolic effects of insulin and proinsulin secretion
Authors: Johansson H‐E. , Öhrvall M. , Haenni A. , Sundbom M. , Edén Engström B. , Karlsson F. A. , Zethelius B.
Published: September 2007

Aims  Hyperproinsulinaemia is associated with obesity and is a risk factor for Type 2 diabetes. We explored the dynamics of proinsulin and insulin and postprandial effects on glucose and lipids in subjects who had undergone gastric bypass (GBP) surgery compared with morbidly obese (MO) subjects and normal weight control subjects (NW).

Methods  Subjects free from diabetes were recruited: 10 previously MO subjects [body mass index (BMI) ± sd, 34.8 ± 6.2 kg/m2] who had undergone GBP surgery, 10 MO subjects (BMI 44 ± 3.1 kg/m2) and 12 NW control subjects (BMI 23.2 ± 2.4 kg/m2). After an overnight fast, a standard meal (2400 kJ) was ingested and glucose, proinsulin, insulin free fatty acids and triglycerides were determined up to 180 min.

Results  Fasting proinsulin was similar in the GBP group and NW control subjects, but threefold increased in MO subjects (P < 0.05). Postprandial AUC for glucose was similar in the three groups and AUC for proinsulin was high in MO, intermediate in the GBP group and lowest in NW control subjects (P for trend = 0.020). Postprandial proinsulin at 60 min was similar in the GBP group and MO subjects and twofold higher than in NW control subjects. Postprandial proinsulin at 180 min was normal in the GBP group, but fivefold increased in MO subjects (P = 0.008). Insulin increased rapidly at 30 min in the GBP group and was normal at 90 min, whereas insulin was still increased at 90–180 min in the MO subjects (P < 0.001).

Conclusions  MO subjects, free from diabetes, have elevated proinsulin concentrations in the fasting as well as the postprandial phase. After GBP surgery markedly lower fasting and postprandial proinsulin concentrations were observed, although BMI was higher compared with NW control subjects.
Stroke prediction and stroke prevention with atorvastatin in the Collaborative Atorvastatin Diabetes Study (CARDS)
Authors: Hitman G. A. , Colhoun H. , Newman C. , Szarek M. , Betteridge D. J. , Durrington P. N. , Fuller J. , Livingstone S. , Neil H. A. W. ,   on behalf of the CARDS Investigators
Published: September 2007

Aims  Patients with Type 2 diabetes have an elevated risk of stroke. The role of lipid levels and diabetes‐specific factors in risk prediction of stroke is unclear, and estimates of efficacy of lipid‐lowering therapy vary between trials. We examined predictors of stroke and the effect of atorvastatin on specific stroke subtypes in Type 2 diabetes in the Collaborative Atorvastatin Diabetes Study (CARDS) [a trial of 2838 participants with mean low‐density lipoprotein cholesterol < 4.14 mmol/l, no history of macrovascular disease and randomized to atorvastatin 10 mg daily or placebo].

Methods  Median follow‐up was 3.9 years. Cox regression models were used to estimate the effect of atorvastatin on stroke rate and risk of stroke associated with baseline risk factors. Risk factors that predicted stroke in univariate models were examined in a multivariable model.

Results  Independent risk factors predicting stroke were age [10‐year increments; hazard ratio (HR) 2.3, P < 0.001], microalbuminuria (albumin : creatinine ratio > 2.5 mg/mmol; HR 2.0, P = 0.007) and glycaemic control (HbA1c > 10%; HR 2.7, P = 0.007). Women were at lower risk of stroke (HR 0.3, P = 0.004). Lipids did not predict stroke. Of 60 first strokes, 47 were non‐haemorrhagic, 13 were indeterminate and none was definitely haemorrhagic. Atorvastatin treatment was associated with 50% reduction in non‐haemorrhagic stroke (95% confidence interval 9%–72%P = 0.024), similar to the 48% reduction (11%–69%) for all strokes combined.

Conclusions  Diabetes‐specific risk factors are important predictors of stroke in Type 2 diabetes. Despite the lack of association between baseline lipids and first stroke, there was a reduction of 50% of non‐haemorrhagic strokes associated with atorvastatin treatment in the CARDS population.
Multiple Imputation: An Alternative to Top Coding for Statistical Disclosure Control
Authors: An Di , Little Roderick J. A.
Published: September 2007

Top coding of extreme values of variables like income is a common method of statistical disclosure control, but it creates problems for the data analyst. The paper proposes two alternative methods to top coding for statistical disclosure control that are based on multiple imputation. We show in simulation studies that the multiple-imputation methods provide better inferences of the publicly released data than top coding, using straightforward multiple-imputation methods of analysis, while maintaining good statistical disclosure control properties. We illustrate the methods on data from the 1995 Chinese household income project.
Small Area Estimates of Labour Force Participation Under a Multinomial Logit Mixed Model
Authors: Molina Isabel , Saei Ayoub , José Lombardía M.
Published: September 2007

A new methodology is developed for estimating unemployment or employment characteristics in small areas, based on the assumption that the sample totals of unemployed and employed individuals follow a multinomial logit model with random area effects. The method is illustrated with UK labour force data aggregated by sex–age groups. For these data, the accuracy of direct estimates is poor in comparison with estimates that are derived from the multinomial logit model. Furthermore, two different estimators of the mean-squared errors are given: an analytical approximation obtained by Taylor linearization and an estimator based on bootstrapping. A simulation study for comparison of the two estimators shows the good performance of the bootstrap estimator.
A THEORY OF THE INFORMAL SECTOR
Authors: AZUMA YOSHIAKI , GROSSMAN HERSCHEL I.
Published: September 2007

In many countries, especially poor countries, a heavy burden of taxes, fees, bureaucratic hassles, and bribes drives many producers into an informal sector. This paper shows that we can attribute the existence of a large informal sector to the fact that, because productive endowments contain important unobservable components, the state cannot adjust the amounts that it extracts from producers in the formal sector finely according to each producer's endowment. Given this fact, we find that if the endowment of well‐endowed producers is sufficiently large relative to poorly endowed producers, or if their number is relatively large, or if the quality of public services is sufficiently low, then the state extracts a large enough amount from producers in the formal sector that poorly endowed producers choose to work in the informal sector. This result obtains both for a proprietary state, which maximizes its own net revenue, and for a hypothetical benevolent state, which would maximize total net output. But, we also find that there exist combinations of the distribution of endowments and the quality of public services such that the policies of a proprietary state, but not the policies of a hypothetical benevolent state, would cause poorly endowed producers to work in the informal sector.
Early adolescent outcomes of institutionally deprived and non‐deprived adoptees. III. Quasi‐autism
Authors: Rutter Michael , Kreppner Jana , Croft Carla , Murin Marianna , Colvert Emma , Beckett Celia , Castle Jenny , Sonuga‐Barke Edmund
Published: September 2007

Background:  Some young children reared in profoundly depriving institutions have been found to show autistic‐like patterns, but the developmental significance of these features is unknown.

Methods:  A randomly selected, age‐stratified, sample of 144 children who had experienced an institutional upbringing in Romania and who were adopted by UK families was studied at 4, 6, and 11 years, and compared with a non‐institutionalised sample of 52 domestic adoptees. Twenty‐eight children, all from Romanian institutions, for whom the possibility of quasi‐autism had been raised, were assessed using the Autism Diagnostic Interview‐Revised (ADI‐R) and the Autism Diagnostic Observation Schedule (ADOS) at the age of 12 years.

Results:  Sixteen children were found to have a quasi‐autistic pattern; a rate of 9.2% in the Romanian institution‐reared adoptees with an IQ of at least 50 as compared with 0% in the domestic adoptees. There were a further 12 children with some autistic‐like features, but for whom the quasi‐autism designation was not confirmed. The follow‐up of the children showed that a quarter of the children lost their autistic‐like features by 11. Disinhibited attachment and poor peer relationships were also present in over half of the children with quasi‐autism.

Conclusions:  The findings at age 11/12 years confirmed the reality and clinical significance of the quasi‐autistic patterns seen in over 1 in 10 of the children who experienced profound institutional deprivation. Although there were important similarities with ‘ordinary’ autism, the dissimilarities suggest a different meaning.
Social maturity and theory of mind in typically developing children and those on the autism spectrum
Authors: Peterson Candida C. , Slaughter Virginia P. , Paynter Jessica
Published: September 2007

Background:  Results of several studies using the Vineland scale to explore links between social behavior and theory of mind (ToM) have produced mixed results, especially for children on the autism spectrum. The present pair of studies developed a psychometrically sound, age‐referenced measure of social maturity to explore these issues further.

Method:  In Study 1, 37 typically developing preschoolers took a battery of standard false belief tests of ToM and were rated by their teachers on a newly developed age‐referenced social maturity scale with 7 items. In Study 2, a further group of 43 children aged 4 to 12 years (13 with autism, 14 with Asperger's disorder and 16 with typical development) took part in the same procedure.

Results:  In Study 1, ToM was found to predict typical preschoolers’ social maturity independently of age and verbal maturity. In Study 2, children with autism scored below age‐matched and younger typical developers in both ToM and social maturity. Those with Asperger's disorder did well on ToM but poorly on social maturity. Study 2 replicated Study 1’s finding (for typical children and for the full sample) that ToM was linked with social maturity independently of age and verbal ability, although the link was not independent of autism diagnosis.

Conclusions:  Teachers are capable of rating children's social behavior with peers as advanced, on‐time or delayed for their age. Suggestive links between these ratings and ToM require further investigation, especially among children on the autism spectrum.
Isolation of polymorphic tri‐ and tetranucleotide microsatellite loci for the highly endangered Baw Baw frog (Philoria frosti)
Authors: WHEATON LEANNE , DONNELLAN STEPHEN C. , GARDNER MICHAEL G. , HOLLIS GREGORY J.
Published: September 2007

We isolated 15 polymorphic microsatellite loci for the Baw Baw frog, Philoria frosti, from a genomic library enriched for (AAC)n and (AAAG)n repetitive elements. The number of alleles ranges from two to 14 per locus with the observed heterozygosity ranging from 0.04 to 0.96.
Cardiac MRI: accuracy of simultaneous measurement of left and right ventricular parameters using three different sequences
Authors: Koskenvuo Juha W. , Karra Henna , Lehtinen Jaakko , Niemi Pekka , Pärkkä Jussi , Knuuti Juhani , Hartiala Jaakko J.
Published: September 2007

Background and aim:  We evaluated a value of Qp/Qs (left‐to‐right shunt measurement) using volumetric cardiac magnetic resonance (CMR) cardiac output (CO) measurements. We defined intraobserver, interobserver variability and reproducibility of left and right ventricular parameters by CMR. Furthermore, we studied whether shortened acquisition time has an effect on the accuracy of left and right ventricular parameters both in healthy volunteers and in patients with cardiovascular disease.

Methods:  Sixteen subjects were enrolled in this study. Group A (n = 8, five males) consisted of healthy volunteers with a mean age of 25·9 years (range 24–30). Group B (n = 8, four males) was heterogenic consisting of patients with left ventricular (LV) hypertrophy, hypertension or coronary artery disease with their mean age of 56·3 years (range 38–70).

Results:  The measured Qp/Qs as calculated from the right and LV CO was 0·87 ± 0·13. Overall variability [as presented with the lowest coefficient of variation (CV)%– the highest CV % of intraobserver, interobserver variability or reproducibility] of LV parameters were for ejection fraction (EF) 1·5–2·8%, stroke volume (SV) 1·3–3·2%, CO 1·4–3·2%, end‐diastolic volume 0·5–3·0%, end‐systolic volume 1·8–6·2% and LV mass 1·1–2·6%. Corresponding values for right ventricular parameters were for EF 1·1–4·2%, SV 1·9–8·2%, CO 1·9–7·6%, end‐diastolic volume 2·1–7·6%, end‐systolic volume 2·8–10·2% and right ventricle mass 2·9–8·3%. There was no statistically significant difference between the results of different sequences.

Conclusions:  The CMR allows accurate Qp/Qs observation but the absolute value is at slightly different level compared with reference methods. Both left and right ventricular parameters are highly reproducible and even small clinically relevant changes can be measured with CMR. The shortened acquisition does not affect significantly to the accuracy of CMR‐derived parameters.
The Challenging Problem of Glass Transition
Authors: Ngai Kia L. , Capaccioli Simone
Published: September 2007

The glass transition phenomena are observed in many different classes of materials and have been studied in various disciplines. It is a long‐standing problem due to the increasing number of important and general experimental facts that challenge conventional theories to explain. A collection of such experimental facts on the structural relaxation is given here, together with the observation that they are either governed by or correlated with the time/frequency dispersion of the structural relaxation. There is a class of secondary relaxations (named after Johari–Goldstein (JG)) that are well‐connected to the structural relaxation in many ways. Thus, a fully successful theory of glass transition must take into consideration the roles played by the dispersion of the structural relaxation and the JG secondary relaxation. The results from our study of mixtures of van der Waals liquids are presented to illustrate these points, and a satisfactory explanation of the data is given. The understanding of the component dynamics gained from the study of these ideal systems is used to elucidate and interpret the experimental data of aqueous mixtures and hydrated proteins, which are more complicated systems. This exercise illustrates the benefit of broadening the study of one class of glass‐forming materials to another class normally investigated by workers in another discipline.
Photoluminescent Properties of SrTiO3:Pr, Al Nanophosphors Synthesized by Microemulsion–Microwave Heating
Authors: Pang Qi , Shi Jianxin , Gong Menglian
Published: September 2007

A novel approach for the preparation of SrTiO3:Pr, Al nanophosphors by microemulsion–microwave heating is reported in this paper. In comparison with the conventional solid‐state sintering processes, this novel method provides a limited small space in a micelle for the formation of nanosized precursors and requires a very short heating time, thus reducing the energy consumption. As a result, small‐sized particles with a narrow size distribution and high purity were produced. Transmission electron microscopy characterizations indicated that the synthesized particles were almost spherical with an averaging diameter of ∼24 nm and agglomerates slightly. The X‐ray diffraction analysis revealed the perovskite cubic structure of SrTiO3:Pr3+ nanoparticles. The luminescent of SrTiO3:Pr, Al phosphors were investigated by photoluminescence. Under 350 nm excitation, SrTiO3:Pr, Al showed a strong red emission, peaking at around 615 nm. The photoluminescence excitation intensity was enhanced by the addition of Al3+ ions.
Experimental and Finite Element Study of the Thermal Conductivity of α‐SiAlON Ceramics
Authors: Kushan Seniz Reyhan , Uzun Ibrahim , Dogan Battal , Mandal Hasan
Published: September 2007

The thermal conductivity of monolithic Y‐Sm/α‐SiAlON was evaluated using experimental data and finite element analysis. The thermal diffusivities of Y, Y‐Dy, and Y‐Ce/α‐SiAlON ceramics were also investigated experimentally for comparison. The maximum achievable thermal conductivity of Y‐Sm/α‐SiAlON has been calculated by the linear extrapolation of the temperature‐based experimental inverse diffusivity data and was used for the numerical calculations. Two‐dimensional model microstructures were built on the base of real microstructure images and applied for calculations. Experimental data and numerical calculations were compared for Y‐Sm/α‐SiAlON, and it was revealed that both results are in good agreement.
Characterization of Heterogeneous Microstructure Evolution in ZrO2–3 mol%Y2O3 during Isothermal Sintering
Authors: Nettleship Ian , Chen Tiandan , Ewsuk Kevin
Published: September 2007

Pore boundary tessellation and quantitative stereology were used to characterize microstructure evolution in ZrO2–3 mol%Y2O3 (3YSZ) that had been pressed to a green density of 46% and isothermally sintered at 1275°C for 0.1–10 h. Scanning electron micrographs showed that, relative to classical sintering models, the sintered 3YSZ microstructure was spatially heterogeneous, and that this heterogeneity affected the way in which the microstructure evolved during sintering. Pore boundary tessellation cell maps revealed the presence of dense regions within the microstructure that grew by the preferential elimination of smaller pores and resulted in larger more widely spaced porosity at longer sintering times. In consequence, the average pore separation distance increased much faster than the average grain size. This would call into question the use of the grain size as a measure of microstructural scale for the prediction of densification kinetics for this material.
Low‐Temperature Sintering and Piezoelectric Properties of CuO‐Added 0.95(Na0.5K0.5)NbO3–0.05BaTiO3 Ceramics
Authors: Park Hwi‐Yeol , Ahn Cheol‐Woo , Cho Kyung‐Hoon , Nahm Sahn , Lee Hyeung‐Gyu , Kang Hyung‐Won , Kim Duk‐Hee , Park Kyeong‐Soon
Published: September 2007

The sintering temperature of 0.95(Na0.5K0.5)NbO3–0.05BaTiO3 (NKN–BT) ceramics needs to be decreased below 1000°C to prevent Na2O evaporation, which can cause difficulties in poling and may eventually degrade their piezoelectric properties. NKN–BT ceramics containing CuO were well sintered at 950°C with grain growth. Poling was easy for all specimens. Densification and grain growth were explained by the formation of a liquid phase. The addition of CuO improved the piezoelectric properties by increasing the grain size and density. High piezoelectric properties of d33=230 pC/N, kp=37%, and ɛ3T/ɛ0=1150 were obtained from the specimen containing 1.0 mol% of CuO synthesized by the conventional solid‐state method.
Assembly and Deagglomeration of Lanthanum Orthoborate Nanobundles
Authors: Ma Jie , Wu Qingsheng , Ding Yaping
Published: September 2007

LaBO3 bundle‐like nanorods are self‐assembled through a novel oxide‐hydrothermal method. In this route, the stoichiometric amounts of La2O3 and boric oxide B2O3 are mixed in proper amounts of water in a surfactant/ligand‐free sealed hydrothermal system. The nanobundles are de‐agglomerated to nanorods by tiny Sm3+ replacing La3+. The characterization of these materials has been carried out by X‐ray powder diffraction, FTIR, thermo‐gravimetric and differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and selected area electron diffraction. As‐prepared aragonite‐type LaBO3 nanorods are fairly controlled to have a high purity, homogeneous, and bundled morphology composed of numerous nanorods with diameter ca. 90 nm. The formation processes and mechanics of LaBO3 nanobundles and nanorods are investigated. The room‐temperature fluorescence properties of various Sm3+‐doped LaBO3 are investigated.
Allometric and ontogenetic patterns related to feeding of a neotropical fish, Satanoperca pappaterra (Perciformes, Cichlidae)
Authors: Cassemiro F. A. S. , Rangel T. F. L. V. B. , Pelicice F. M. , Hahn N. S.
Published: September 2007

Abstract –  This study aims to analyse whether Satanoperca pappaterra changes its feeding habit throughout ontogenetic development, and whether morphological ontogenetic patterns are related to its feeding habit and food capture. We collected 258 individuals in the Cuiabá river basin (Brazil) for analyses. There was a weak relationship between diet and body size, as evidenced by size class and multivariate analyses, and niche breadth did not vary strongly during ontogenetic development. Eight morphometric variables were measured in each individual. We found an isometric relationship for mouth height and width, and for head length. We found positive allometry for snout length and body height in relation to body length, whereas this relationship for intestine length and eye diameter showed negative allometry. These results suggest that morphology and consequently diet vary weakly during ontogenetic development of S. pappaterra.
Human Adenovirus Modulates Surfactant Phospholipid Trafficking
Authors: Miakotina Olga L. , McCoy Diann M. , Shi Lei , Look Dwight C. , Mallampalli Rama K.
Published: September 2007

Surfactant, highly enriched with phosphatidylcholine (PC), is secreted into the airspace by a classic apical secretory route, thereby maintaining lung stability. Herein, we show that adenoviral infection decreases surfactant PC in lungs by inhibiting its apical secretion and redirecting its export in alveolar cells by a basolateral route. These effects were not observed with replication‐deficient adenovirus (Ad), specifically lacking early region 1 (E1) gene products. Adenoviral stimulation of basolateral PC export from cells was not observed after pharmacologic inhibition of ATP‐binding cassette proteins, after introduction of small interfering RNA to the lipid pump ATP‐binding cassette transporter A1 (ABCA1) or in ABCA1‐defective human Tangier disease fibroblasts. Adenovirus and its E1A gene product increased ABCA1 levels by transcriptionally activating the ABCA1 gene. Thus, Ad lowers surfactant, in part, by triggering ABCA1‐directed basolateral PC export, thereby limiting the cellular pool of surfactant PC destined for apical secretion. The results support a novel pathway, whereby a viral pathogen disrupts surfactant trafficking.
Integral and Associated Lysosomal Membrane Proteins
Authors: Schröder Bernd , Wrocklage Christian , Pan Cuiping , Jäger Ralf , Kösters Bernd , Schäfer Helmut , Elsässer Hans‐Peter , Mann Matthias , Hasilik Andrej
Published: September 2007

We searched for novel proteins in lysosomal membranes, tentatively participating in molecular transport across the membrane and/or in interactions with other compartments. In membranes purified from placental lysosomes, we identified 58 proteins, known to reside at least partially in the lysosomal membrane. These included 17 polypeptides comprising or associated with the vacuolar adenosine triphosphatase. We report on additional 86 proteins that were significantly enriched in the lysosomal membrane fraction. Among these, 12 novel proteins of unknown functions were found. Three were orthologues of rat proteins that have been identified in tritosomes by Bagshaw RD et al. (A proteomic analysis of lysosomal integral membrane proteins reveals the diverse composition of the organelle. Mol Cell Proteomics 2005;4:133–143). Here, the proteins encoded by LOC201931 (FLJ38482) and LOC51622 (C7orf28A) were expressed with an appended fluorescent tag in HeLa cells and found to be present in lysosomal organelles. Among the lysosomally enriched proteins, also 16 enzymes and transporters were detected that had not been assigned to lysosomal membranes previously. Finally, our results identified a particular set of proteins with known functions in signaling and targeting to be at least partially associated with lysosomes.
Neurotrophins Redirect p75NTR from a Clathrin‐Independent to a Clathrin‐Dependent Endocytic Pathway Coupled to Axonal Transport
Authors: Deinhardt Katrin , Reversi Alessandra , Berninghausen Otto , Hopkins Colin R. , Schiavo Giampietro
Published: September 2007

The p75 neurotrophin receptor (p75NTR) plays multiple roles in neuronal physiology through interactions with many ligands and coreceptors. However, its intracellular neuronal trafficking prior to and after neurotrophin activation is still poorly characterized. We have previously shown that in response to nerve growth factor (NGF), p75NTR is retrogradely transported along the axons of motor neurons (MNs) in carriers shared with NGF, brain‐derived neurotrophic factor and the tyrosine kinase receptor TrkB. Here, we report that NGF does not enhance the internalization or degradation of p75NTR, which undergoes a rapid dynamin‐dependent and clathrin‐independent recycling process in MNs. Instead, incubation of cells with NGF leads to the redirection of a pool of plasma membrane p75NTR into clathrin‐coated pits. The subsequent internalization of p75NTR via clathrin‐mediated endocytosis, as well as the activity of Rab5, are essential for the sorting of the p75NTR‐containing endosomes to the axonal retrograde transport pathway and for the delivery of p75NTR to the soma. Our findings suggest that the spatial regulation of p75NTR signalling is controlled by these ligand‐driven routes of endocytosis.
Dyneins Across Eukaryotes: A Comparative Genomic Analysis
Authors: Wickstead Bill , Gull Keith
Published: September 2007

Dyneins are large minus‐end‐directed microtubule motors. Each dynein contains at least one dynein heavy chain (DHC) and a variable number of intermediate chains (IC), light intermediate chains (LIC) and light chains (LC). Here, we used genome sequence data from 24 diverse eukaryotes to assess the distribution of DHCs, ICs, LICs and LCs across Eukaryota. Phylogenetic inference identified nine DHC families (two cytoplasmic and seven axonemal) and six IC families (one cytoplasmic). We confirm that dyneins have been lost from higher plants and show that this is most likely because of a single loss of cytoplasmic dynein 1 from the ancestor of Rhodophyta and Viridiplantae, followed by lineage‐specific losses of other families. Independent losses in Entamoeba mean that at least three extant eukaryotic lineages are entirely devoid of dyneins. Cytoplasmic dynein 2 is associated with intraflagellar transport (IFT), but in two chromalveolate organisms, we find an IFT footprint without the retrograde motor. The distribution of one family of outer‐arm dyneins accounts for 2‐headed or 3‐headed outer‐arm ultrastructures observed in different organisms. One diatom species builds motile axonemes without any inner‐arm dyneins (IAD), and the unexpected conservation of IAD I1 in non‐flagellate algae and LC8 (DYNLL1/2) in all lineages reveals a surprising fluidity to dynein function.
A Role for ARF6 and ARNO in the Regulation of Endosomal Dynamics in Neurons
Authors: Hernández‐Deviez Delia , Mackay‐Sim Alan , Wilson Jean M.
Published: September 2007

During development, neuronal processes extend, branch and navigate to ultimately synapse with target tissue. We have shown a regulatory role for ARNO and ARF6 in dendritic branching and axonal elongation and branching during neuritogenesis, particularly with respect to cytoskeletal dynamics. Here, we have examined the role of ARF6 and the ARF GEF ARNO in endosomal dynamics during neurite elongation in hippocampal neurons. Axonal and dendritic endosomes were labeled by expression of the endosomal marker, endotubin. Expression of endotubin‐green fluorescent protein resulted in targeting to tubular–vesicular structures throughout the somatodendritic and axonal domains. These endosomal structures did not colocalize with conventional early or late endosomal markers or with the synaptic vesicle marker, SV2. However, they did label with internalized lectin, indicating that they are endosomal structures. Expression of catalytically inactive ARNO (ARNO‐E156K) or inactive ARF6 (ARF6‐T27N) caused a redistribution of endotubin to the cell surface of the axons and dendrites. In contrast, expression of these constructs had no effect upon the distribution of SV2‐positive structures. Furthermore, expression of inactive ARF1 (ARF1‐T31N) did not change endotubin distribution. These results suggest that endotubin labels a distinct endosomal structure in neurons and that ARNO and ARF6 mediate neurite extension through the regulation of this compartment.
Unraveling multistate unfolding of pig kidney fructose‐1,6‐bisphosphatase using single tryptophan mutants
Authors: Ludwig Heide C. , Pardo Fabian N. , Asenjo Joel L. , Maureira Marco A. , Yañez Alejandro J. , Slebe Juan C.
Published: September 2007

Pig kidney fructose‐1,6‐bisphosphatase is a homotetrameric enzyme which does not contain tryptophan. In a previous report the guanidine hydrochloride‐induced unfolding of the enzyme has been described as a multistate process [Reyes, A. M., Ludwig, H. C., Yañez, A. J., Rodriguez, P. H and Slebe, J. C. (2003) Biochemistry 42, 6956–6964]. To monitor spectroscopically the unfolding transitions, four mutants were constructed containing a single tryptophan residue either near the C1–C2 or the C1–C4 intersubunit interface of the tetramer. The mutants were shown to retain essentially all of the structural and kinetic properties of the enzyme isolated from pig kidney. The enzymatic activity, intrinsic fluorescence, size‐exclusion chromatographic profiles and 1‐anilinonaphthalene‐8‐sulfonate binding by the mutants were studied under unfolding equilibrium conditions. The unfolding profiles were multisteps, and formation of hydrophobic structures was detected. The enzymatic activity of wild‐type and mutant FBPases as a function of guanidine hydrochloride concentration showed an initial enhancement (maximum ∼ 30%) followed by a biphasic decay. The activity and fluorescence results indicate that these transitions involve conformational changes in the fructose‐1,6‐bisphosphate and AMP domains. The representation of intrinsic fluorescence data as a ‘phase diagram’ reveals the existence of five intermediates, including two catalytically active intermediates that have not been previously described, and provides the first spectroscopic evidence for the formation of dimers. The intrinsic fluorescence unfolding profiles indicate that the dimers are formed by selective disruption of the C1–C2 interface.
The 2‐oxoacid dehydrogenase multi‐enzyme complex of the archaeon Thermoplasma acidophilum − recombinant expression, assembly and characterization
Authors: Heath Caroline , Posner Mareike G. , Aass Hans C. , Upadhyay Abhishek , Scott David J. , Hough David W. , Danson Michael J.
Published: September 2007

The aerobic archaea possess four closely spaced, adjacent genes that encode proteins showing significant sequence identities with the bacterial and eukaryal components comprising the 2‐oxoacid dehydrogenase multi‐enzyme complexes. However, catalytic activities of such complexes have never been detected in the archaea, although 2‐oxoacid ferredoxin oxidoreductases that catalyze the equivalent metabolic reactions are present. In the current paper, we clone and express the four genes from the thermophilic archaeon, Thermoplasma acidophilum, and demonstrate that the recombinant enzymes are active and assemble into a large (Mr = 5 × 106) multi‐enzyme complex. The post‐translational incorporation of lipoic acid into the transacylase component of the complex is demonstrated, as is the assembly of this enzyme into a 24‐mer core to which the other components bind to give the functional multi‐enzyme system. This assembled complex is shown to catalyze the oxidative decarboxylation of branched‐chain 2‐oxoacids and pyruvate to their corresponding acyl‐CoA derivatives. Our data constitute the first proof that the archaea possess a functional 2‐oxoacid dehydrogenase complex.
Induction of translationally controlled tumor protein (TCTP) by transcriptional and post‐transcriptional mechanisms
Authors: Schmidt Irina , Fähling Michael , Nafz Benno , Skalweit Angela , Thiele Bernd‐Joachim
Published: September 2007

Expression of the human TPT1 gene coding for translationally controlled tumor protein (TCTP) was investigated in Calu‐6 and Cos‐7 cells under the influence of 4β‐phorbol 12‐myristate 13‐acetate (PMA), forskolin, dioxin and the heavy metals copper, nickel and cobalt. Transcriptional and post‐transcriptional aspects of the mechanism were analyzed by TCTP mRNA/protein quantification, luciferase reporter gene assays depending on TPT1 promoter sequences or TCTP mRNA 5′/3′‐UTRs and investigation of the interaction of RNA‐binding proteins with UTRs by UV‐crosslinking. PMA, forskolin, dioxin, cobalt and nickel induced TCTP expression in 24 h in both cell lines about 2.2–3.2‐fold at the mRNA level and 1.6–2.2‐fold at the protein level. The highest induction rate, 4.5–5.0‐fold at the mRNA level and 3.5–4.0‐fold at the protein level, was observed with copper. TPT1 promoter assays showed transcriptional activation by PMA, forskolin and dioxin (2.0–3.1‐fold) and a 7.0–8.0‐fold increase by copper, whereas cobalt and nickel had no effect. Deletion analysis revealed that copper‐dependent transcriptional control was transmitted by a metal‐responsive element residing in the TPT1 promoter. Post‐transcriptional activation of TCTP expression was associated with the action of dioxin, nickel, cobalt (1.8–2.3‐fold) and copper (2.5–3.0‐fold), whereas stimulation of TCTP synthesis by copper was mediated by the TCTP mRNA 3′‐UTR (3.2‐fold) but not by the 5′‐UTR (0.5‐fold). mRNA stabilization was found to mediate these effects of cobalt and nickel. Post‐transcriptional regulation was associated with qualitative and quantitative changes in the binding of specific RNA‐binding proteins to UTRs.
Aplysia temptin − the ‘glue’ in the water‐borne attractin pheromone complex
Authors: Cummins Scott F. , Xie Fang , de Vries Melissa R. , Annangudi Suresh P. , Misra Milind , Degnan Bernard M. , Sweedler Jonathan V. , Nagle Gregg T. , Schein Catherine H.
Published: September 2007

Temptin, a component of the complex of water‐borne protein pheromones that stimulate attraction and mating behavior in the marine mollusk Aplysia, has sequence homology to the epidermal growth factor (EGF)‐like domains of higher organisms that mediate protein–cell surface contact during fertilization and blood coagulation. In this work, recombinant temptin for structural and functional studies was produced in Escherichia coli using a cold shock promoter and purified by RP‐HPLC. CD spectra confirmed a predominantly β‐sheet structure. Two disulfide bonds were determined via limited proteolysis and MS. One internal disulfide (Cys57‐Cys77) was predicted from initial alignments with class I EGF‐like domains; the second, between Cys18 and Cys103, could protect temptin against proteolysis in seawater and stabilize its interacting surface. A three‐dimensional model of temptin was prepared with our MPACK suite, based on the Ca2+‐binding, EGF‐like domain of the extracellular matrix protein fibrillin. Two temptin residues, Trp52 and Trp79, which align with cysteine residues conserved in fibrillins, lie adjacent to and could stabilize the disulfide bonds and a proposed metal‐binding loop. The water‐borne pheromone attractin in egg cordon eluates is complexed with other proteins. Docking results with our model and the NMR structure of attractin suggest that one face of temptin interacts with the pheromone, perhaps controlling its access to the cellular receptors. Gel shifts confirmed that temptin complexes with wild‐type attractin. These results indicate that temptin, analogous to the role of fibrillin in controlling transforming growth factor‐β concentration, modulates pheromone signaling by direct binding to attractin.
Evaluation of the temperature of different refrigerant sprays used as a pulpal test
Authors: De Morais Carlos Alberto Herrero , Bernardineli Norberti , Lima Walter Moreira , Cupertino Rogério Rodrigues , Guerisoli Danilo Mathias Zanello
Published: September 2007

The temperature of different refrigerant sprays (Endo‐Ice, Endo‐Frost, Coolermatic and Sprayon Contact and Tuner Cleaner) used as pulpal tests were evaluated in vitro. A thermocouple placed inside the pulp chamber of a maxillary central incisor was used to register the temperature changes when the refrigerant sprays were applied with a cotton swab, for 10 s. Results indicate that Endo‐Ice and Endo‐Frost presented the lowest temperatures among the refrigerant sprays tested. Temperatures measured inside the pulp chamber, however, were statistically similar in all groups.
Comparison of four hematology analyzers, CELL‐DYN Sapphire, ADVIA 120, Coulter LH 750, and Sysmex XE‐2100, in terms of clinical usefulness
Authors: KANG S.‐H. , KIM H. K. , HAM C. K. , LEE D. S. , CHO H.‐I.
Published: September 2007

We evaluated the clinical usefulness (leukocyte distribution classification, morphologic classification, and morphologic flags) of the following four hematology analyzers: CELL‐DYN Sapphire (CD‐Sapphire) (Abbott Diagnostics, Santa Clara, CA, USA), ADVIA 120 (Bayer Diagnostics, Tarrytown, NY, USA), Beckman Coulter LH 750 (Beckman Coulter, Miami, FL, USA), and Sysmex XE‐2100 (TOA Medical Electronics Co., Kobe, Japan). Four hundred thirty samples from patients and 100 samples from healthy individuals were analyzed. For distributional classification, the sensitivity rates of CD‐Sapphire, ADVIA 120, LH 750, and XE‐2100 were 93.1, 95.9, 94.9, and 94.9%, respectively, and the efficiency rates were 80.7, 81.6, 84.1, and 84.2%, respectively. For morphologic classification, the sensitivity rates of CD‐Sapphire, ADVIA 120, LH 750, and XE‐2100 were 88.6, 93.2, 77.3, and 94.3%, respectively, and the efficiency rates were 80.9, 73.0, 79.5, and 74.2%, respectively. Comparing the findings in different morphologic flags, XE‐2100 showed the highest sensitivity for Blasts flag (90.9%); CD‐Sapphire showed the highest sensitivity for Immature granulocytes and/or Left‐shift flag (85.5%); ADVIA 120 showed the highest sensitivity for Atypical lymphocytes flag (60.0%); and LH 750 showed the highest sensitivity for Nucleated RBC flag (75.0%). Our results demonstrate that the four analyzers are comparable in overall performance.
Role of hepatitis C virus proteins (C, NS3, NS5A) in hepatic oncogenesis
Authors: Kasprzak Aldona , Adamek Agnieszka
Published: September 2007

In recent years, the effects of hepatitis C virus (HCV) proteins on hepatocarcinogenesis have undergone intense investigations. The potentially oncogenic proteins include at least three HCV proteins: core (C) protein, NS3, and NS5A. Several authors indicated relationships between subcellular localization, concentration, a specific molecular form of the proteins (full length, truncated, phosphorylated), the presence of specific domains (the nuclear localization signal homologous to e.g. Bcl‐2) and their effects on the mechanisms linked to oncogenesis. The involvement of all the proteins has been described as being in control of the cell cycle, through interactions with key proteins of the process (p53, p21, cyclins, proliferating cell nuclear antigen), transcription factors, proto‐oncogenes, growth factors/cytokines and their receptors, and proteins linked to the apoptotic process. Untilnow, the involvement of the core protein of HCV in liver carcinogenesis is the most recognized. One of the most common proteins affected by HCV proteins is the p53 tumor‐suppressor protein. Thep21/WAF1gene is a major target of p53, and the effect of HCV proteins on the gene is frequently considered in parallel. The results of studies on the effects of HCV proteins on the apoptotic process are controversial. This work summarizes the information collected thus far in the field of HCV molecular virology and principal intracellular signaling pathways in which HCV oncogenic proteins are involved.
Comparison of simulations and data from a seismo-acoustic tank experiment
Authors: Collis Jon M. , Siegmann William L. , Collins Michael D. , Simpson Harry J. , Soukup Raymond J.
Published: September 2007

A tank experiment was carried out to investigate underwater sound propagation over an elastic bottom in flat and sloping configurations. The purpose of the experiment was to evaluate range-dependent propagation models with high-quality experimental data. The sea floor was modeled as an elastic medium by a polyvinyl chloride slab. The relatively high rigidity of the slab requires accounting for shear waves in this environment. Acoustic measurements were obtained along virtual arrays in the water column using a robotic apparatus. Elastic parabolic equation solutions are in excellent agreement with data.
Attenuation of high-level impulses by earmuffs
Authors: Zera Jan , Mlynski Rafal
Published: September 2007

Attenuation of high-level acoustic impulses (noise reduction) by various types of earmuffs was measured using a laboratory source of type A impulses and an artificial test fixture compatible with the ISO 4869-3 standard. The measurements were made for impulses of peak sound-pressure levels (SPLs) from 150 to 170dB. The rise time and A duration of the impulses depended on their SPL and were within a range of 12–400μs (rise time) and 0.4–1.1ms (A duration). The results showed that earmuff peak level attenuation increases by about 10dB when the impulse’s rise time and the A duration are reduced. The results also demonstrated that the signals under the earmuff cup have a longer rise and A duration than the original impulses recorded outside the earmuff. Results of the measurements were used to check the validity of various hearing damage risk criteria that specify the maximum permissible exposure to impulse noise. The present data lead to the conclusion that procedures in which hearing damage risk is assessed only from signal attenuation, without taking into consideration changes in the signal waveform under the earmuff, tend to underestimate the risk of hearing damage.
Attenuation in trabecular bone: A comparison between numerical simulation and experimental results in human femur
Authors: Bossy Emmanuel , Laugier Pascal , Peyrin Françoise , Padilla Frédéric
Published: September 2007

Numerical simulations (finite-difference time domain) are compared to experimental results of ultrasound wave propagation through human trabecular bones. Three-dimensional high-resolution microcomputed tomography reconstructions served as input geometry for the simulation. The numerical simulation took into account scattering, but not absorption. Simulated and experimental values of the attenuation coefficients (α, dB/cm) and the normalized broadband ultrasound attenuation (nBUA, dB/cm/MHz) were measured and compared on a set of 28 samples. While experimental and simulated nBUA values were highly correlated (R2=0.83), and showed a similar dependence with bone volume fraction, the simulation correctly predicted experimental nBUA values only for low bone volume fraction (BV/TV). Attenuation coefficients were underestimated by the simulation. The absolute difference between experimental and simulated α values increased with both BV/TV and frequency. As a function of frequency, the relative difference between experimental and simulated α values decreased from 60% around 400kHz to 30% around 1.2MHz. Under the assumption that the observed discrepancy expresses the effect of the absorption, our results suggests that nBUA and its dependence on BV/TV can be mostly explained by scattering, and that the relative contribution of scattering to α increases with frequency, becoming predominant (>50 %) over absorption for frequencies above 600kHz.
Alpha-plutonium’s polycrystalline elastic moduli over its full temperature range
Authors: Migliori A. , Pantea C. , Ledbetter H. , Stroe I. , Betts J. B. , Mitchell J. N. , Ramos M. , Freibert F. , Dooley D. , Harrington S. , Mielke C. H.
Published: September 2007

α -plutonium’s volume-corrected polycrystal elastic moduli were measured between 18K and the upper limit of its occurrence, near 400K. The two independent moduli for a polycrystal—bulk and shear—behave smoothly, indicating no phase transition. Both moduli show the same 50% increase on cooling, an order of magnitude larger than in other metals. The Debye temperature obtained from low-temperature elastic moduli, 207K, significantly exceeds most previous estimates. The Gruneisen parameter γ=5.3, obtained from the temperature dependence of the bulk modulus, is intermediate among previous estimates using other approaches, α-plutonium’s Poisson ratio ν is low: 0.18, nearly temperature independent, and its small decrease on warming opposes usual behavior. The high γ, large but equal bulk modulus and shear modulus fractional stiffening on cooling, and near-temperature-invariant ν are attributed to a single mechanism: 5-f electron localization—delocalization.