bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic Studies of Polyhydroxybutyrate Granule Formation in
Wautersia eutropha
H16 by Transmission Electron Microscopy
Authors: Tian Jiamin , Sinskey Anthony J. , Stubbe JoAnne 
Published: May 2005

ABSTRACT

Wautersia eutropha
, formerly known as
Ralstonia eutropha
, a gram-negative bacterium, accumulates polyhydroxybutyrate (PHB) as insoluble granules inside the cell when nutrients other than carbon are limited. In this paper, we report findings from kinetic studies of granule formation and degradation in
W. eutropha
H16 obtained using transmission electron microscopy (TEM). In nitrogen-limited growth medium, the phenotype of the cells at the early stages of granule formation was revealed for the first time. At the center of the cells, dark-stained “mediation elements” with small granules attached were observed. These mediation elements are proposed to serve as nucleation sites for granule initiation. TEM images also revealed that when
W. eutropha
cells were introduced into nitrogen-limited medium from nutrient-rich medium, the cell size increased two- to threefold, and the cells underwent additional volume changes during growth. Unbiased stereology was used to analyze the two-dimensional TEM images, from which the average volume of a
W. eutropha
H16 cell and the total surface area of granules per cell in nutrient-rich and PHB production media were obtained. These parameters were essential in the calculation of the concentration of proteins involved in PHB formation and utilization and their changes with time. The extent of protein coverage of the granule surface area is presented in the accompanying paper (J. Tian, A. He, A. Lawrence, P. Liu, N. Watson, A. J. Sinskey, and J. Stubbe, J. Bacteriol.
187:
3825-3832, 2005).
Structure and Genome Organization of AFV2, a Novel Archaeal Lipothrixvirus with Unusual Terminal and Core Structures
Authors: Häring Monika , Vestergaard Gisle , Brügger Kim , Rachel Reinhard , Garrett Roger A. , Prangishvili David 
Published: May 2005

ABSTRACT

A novel filamentous virus, AFV2, from the hyperthermophilic archaeal genus
Acidianus
shows structural similarity to lipothrixviruses but differs from them in its unusual terminal and core structures. The double-stranded DNA genome contains 31,787 bp and carries eight open reading frames homologous to those of other lipothrixviruses, a single tRNA
Lys
gene containing a 12-bp archaeal intron, and a 1,008-bp repeat-rich region near the center of the genome.
Alginate Lyase (AlgL) Activity Is Required for Alginate Biosynthesis in
Pseudomonas aeruginosa
Authors: Albrecht Mark T. , Schiller Neal L. 
Published: May 2005

ABSTRACT

To determine whether AlgL's lyase activity is required for alginate production in
Pseudomonas aeruginosa
, an
algLΔ
::Gm
r
mutant (FRD-MA7) was created.
algL
complementation of FRD-MA7 restored alginate production, but
algL
constructs containing mutations inactivating lyase activity did not, demonstrating that the enzymatic activity of AlgL is required for alginate production.
Methylotrophic Autotrophy in
Beijerinckia mobilis
Authors: Dedysh Svetlana N. , Smirnova Ksenia V. , Khmelenina Valentina N. , Suzina Natalia E. , Liesack Werner , Trotsenko Yuri A. 
Published: May 2005

ABSTRACT

Representatives of the genus
Beijerinckia
are known as heterotrophic, dinitrogen-fixing bacteria which utilize a wide range of multicarbon compounds. Here we show that at least one of the currently known species of this genus, i.e.,
Beijerinckia mobilis
, is also capable of methylotrophic metabolism coupled with the ribulose bisphosphate (RuBP) pathway of C
1
assimilation. A complete suite of dehydrogenases commonly involved in the sequential oxidation of methanol via formaldehyde and formate to CO
2
was detected in cell extracts of
B. mobilis
grown on CH
3
OH. Carbon dioxide produced by oxidation of methanol was further assimilated via the RuBP pathway as evidenced by reasonably high activities of phosphoribulokinase and ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Detection and partial sequence analysis of genes encoding the large subunits of methanol dehydrogenase (
mxaF
) and form I RubisCO (
cbbL
) provided genotypic evidence for methylotrophic autotrophy in
B. mobilis
.
The London Underground: dust and hazards to health
Authors: Seaton A , Cherrie J , Dennekamp M , Donaldson K , Hurley J F , Tran C L 
Published: May 2005

Aims:To assess hazards associated with exposure to dust in the London Underground railway and to provide an informed opinion on the risks to workers and the travelling public of exposure to tunnel dust.Methods:Concentrations of dust, as mass (PM2.5) and particle number, were measured at different underground stations and in train cabs; its size and composition were analysed; likely maximal exposures of staff and passengers were estimated; and in vitro toxicological testing of sample dusts in comparison with other dusts was performed.Results:Concentrations on station platforms were 270–480 μg/m3PM2.5and 14 000–29 000 particles/cm3. Cab concentrations over a shift averaged 130–200 μg/m3and 17 000–23 000 particles/cm3. The dust comprised by mass approximately 67% iron oxide, 1–2% quartz, and traces of other metals, the residue being volatile matter. The finest particles are drawn underground from the surface while the coarser dust is generated by interaction of brakes, wheels, and rails. Taking account of durations of exposure, drivers and station staff would have maximum exposures of about 200 μg/m3over eight hours; the occupational exposure standard for welding fume, as iron oxide, is 5 mg/m3over an eight hour shift. Toxicology showed the dust to have cytotoxic and inflammatory potential at high doses, consistent with its composition largely of iron oxide.Discussion:It is unjustifiable to compare PM2.5exposure underground with that on the surface, since the adverse effects of iron oxide and combustion generated particles differ. Concentrations of ultrafine particles are lower and of coarser (PM2.5) particles higher underground than on the surface. The concentrations underground are well below allowable workplace concentrations for iron oxide and unlikely to represent a significant cumulative risk to the health of workers or commuters.
Supermarket baker’s asthma: how accurate is routine health surveillance?
Authors: Brant A , Nightingale S , Berriman J , Sharp C , Welch J , Newman Taylor A J , Cullinan P 
Published: May 2005

Background:Regular health surveillance is commonly recommended for workers exposed to occupational antigens but little is known about how effective it is in identifying cases.Aims:To report one large company’s surveillance and compare its findings with those of a standard cross-sectional survey in the same workforce.Methods:A supermarket company with 324 in-store bakeries producing bread from raw ingredients conducted a three-stage health surveillance programme in around 3000 bakery employees. The first stage involved the administration of a simple respiratory questionnaire. If chest symptoms were present a second questionnaire focusing on their work relationship was administered. If positive a blood sample was requested for the measurement of specific IgE to flour and fungal α-amylase. The results were compared to an independent cross-sectional survey of employees in 20 of the company’s stores.Results:Two hundred and ninety nine (92%) of the company’s bakeries took part in surveillance. The overall employee response for the first stage was 77%; a quarter of those with respiratory symptoms reported that they were work related. Seventy four (61%) of those with work related chest symptoms had a measurement of specific IgE to either flour or fungal α-amylase, of whom 30 (41%) had a positive result. Surveillance estimated that 1% of bakery employees (1% bakers, 2% managers, 0.6% confectioners) had work related symptoms with specific IgE. This compared with 4% (7.5% bakers, 3.3% managers, 0% confectioners) in the cross-sectional survey (n = 166, 93% response).Conclusion:Comparison with a standard cross-sectional survey suggests that routine surveillance can underestimate the workplace burden of disease. The reasons may include technical or resource issues and uncertainties over confidentiality or the perceived consequences of participation. More research needs to be done looking into the design and efficacy of surveillance in occupational asthma.
Required competencies of occupational physicians: a Delphi survey of UK customers
Authors: Reetoo K N , Harrington J M , Macdonald E B 
Published: May 2005

Background:Occupational physicians can contribute to good management in healthy enterprises. The requirement to take into account the needs of the customers when planning occupational health services is well established.Aims:To establish the priorities of UK employers, employees, and their representatives regarding the competencies they require from occupational physicians; to explore the reasons for variations of the priorities in different groups; and to make recommendations for occupational medicine training curricula in consideration of these findings.Methods:This study involved a Delphi survey of employers and employees from public and private organisations of varying business sizes, and health and safety specialists as well as trade union representatives throughout the UK. It was conducted in two rounds by a combination of computer assisted telephone interview (CATI) and postal survey techniques, using a questionnaire based on the list of competencies described by UK and European medical training bodies.Results:There was broad consensus about the required competencies of occupational physicians among the respondent subgroups. All the competencies in which occupational physicians are trained were considered important by the customers. In the order of decreasing importance, the competencies were: Law and Ethics, Occupational Hazards, Disability and Fitness for Work, Communication, Environmental Exposures, Research Methods, Health Promotion, and Management.Conclusion:The priorities of customers differed from previously published occupational physicians’ priorities. Existing training programmes for occupational physicians should be regularly reviewed and where necessary, modified to ensure that the emphasis of training meets customer requirements.
Proximity of the home to roads and the risk of wheeze in an Ethiopian population
Authors: Venn A , Yemaneberhan H , Lewis S , Parry E , Britton J 
Published: May 2005

Background:There is widespread public concern that exposure to road vehicle traffic pollution causes asthma, but epidemiological studies in developed countries have not generally confirmed a strong effect and may have underestimated the risk as a result of relatively high and widespread exposure to traffic in everyday life.Aims:To investigate the effect of living close to a traffic bearing road on the risk of wheezing in Jimma, Ethiopia where road traffic is generally low and restricted to a limited network of roads.Methods:Data have been previously collected on respiratory symptoms, allergic sensitisation, and numerous demographic and lifestyle factors in a systematic sample of inhabitants of Jimma town. In 2003 the homes of these people were retraced; the shortest distance to the nearest surfaced road, and traffic flows on these roads were measured.Results:Distance measurements were collected for 7609 (80%) individuals. The overall prevalence of wheeze was similar in those living within 150 m of a road compared to those living further away (3.9%v3.7%), but among the 3592 individuals living within 150 m, the risk of wheeze increased significantly in linear relation to proximity to the road (adjusted odds ratio = 1.17 per 30 m proximity, 95% CI 1.01 to 1.36). This relation was stronger, though not significantly so, for roads with above median traffic flows.Conclusion:These findings indicate that living in close proximity to road vehicle traffic is associated with an increased risk of wheeze, but that other environmental factors are also likely to be important.
Use of cellular telephones and brain tumour risk in urban and rural areas
Authors: Hardell L , Carlberg M , Hansson Mild K 
Published: May 2005

Aims:To investigate the association between the use of cellular or cordless telephones and the risk for brain tumours in different geographical areas, urban and rural.Methods:Patients aged 20–80 years, living in the middle part of Sweden, and diagnosed between 1 January 1997 and 30 June 2000 were included. One control matched for sex and age in five year age groups was selected for each case. Use of different phone types was assessed by a questionnaire.Results:The number of participating cases was 1429; there were 1470 controls. An effect of rural living was most pronounced for digital cellular telephones. Living in rural areas yielded an odds ratio (OR) of 1.4 (95% CI 0.98 to 2.0), increasing to 3.2 (95% CI 1.2 to 8.4) with >5 year latency time for digital phones. The corresponding ORs for living in urban areas were 0.9 (95% CI 0.8 to 1.2) and 0.9 (95% CI 0.6 to 1.4), respectively. This effect was most obvious for malignant brain tumours.Conclusion:In future studies, place of residence should be considered in assessment of exposure to microwaves from cellular telephones, although the results in this study must be interpreted with caution due to low numbers in some of the calculations.
A SPATIAL-TEMPORAL ANALYSIS ON PATTERN FORMATION AROUND WATER POINTS IN A SEMI-ARID RANGELAND SYSTEM
Authors: WITTEN G. Q. , RICHARDSON F. D. , SHENKER N. 
Published: May 2005

The spatial grazing pattern of goats around a water point on an arid and semi-arid rangeland system in the Karoo in South Africa was modeled. A dynamic automata model was developed by subdividing a spatial area into subunits called cells and where the dynamics of each cell depends on its present state, the state of its neighbors and external factors such as rainfall. By using a dynamic automata model, the long-term influences on the changes in vegetation composition of two species, namely woody perennials and galenia africana, are investigated. The model relates a preference equation, which is a combination of two parameters, forage density and distance to a water point, to the total amount of time spent by each animal within a particular cell in a year. The model provides evidence that the total number of animals grazing an area, the number of water points in the system and the weighting factors associated with the preference equation, influence the extent of degradation of the area.
DYNAMICS OF INHOMOGENEOUS POPULATIONS AND GLOBAL DEMOGRAPHY MODELS
Authors: KAREV GEORGY P. 
Published: May 2005

The dynamic theory of inhomogeneous populations developed during the last decade predicts several essential new dynamic regimes applicable even to the well-known, simple population models. We show that, in an inhomogeneous population with a distributed reproduction coefficient, the entire initial distribution of the coefficient should be used to investigate real population dynamics. In the general case, neither the average rate of growth nor the variance or any finite number of moments of the initial distribution is sufficient to predict the overall population growth. We developed methods for solving the heterogeneous models and explored the dynamics of the total population size together with the reproduction coefficient distribution. We show that, typically, there exists a phase of "hyper-exponential" growth that precedes the well-known exponential phase of population growth in a free regime. The developed formalism is applied to models of global demography and the problem of "population explosion" predicted by the known hyperbolic formula of world population growth. We prove here that the hyperbolic formula presents an exact solution to the Malthus model with an exponentially distributed reproduction coefficient and that "population explosion" is a corollary of certain implicit unrealistic assumptions. Alternative models of world population growth are derived; they show a notable phenomenon, a transition from protracted hyperbolical growth (the phase of "hyper-exponential" development) to the brief transitional phase of exponential growth and, subsequently, to stabilization. The model solutions are consistent with real data and produce relatively accurate forecasts.
CLINICAL SIMULATION OF OGTT GLUCOSE RESPONSE MODEL FOR DIAGNOSIS OF DIABETIC PATIENT
Authors: GHISTA DHANJOO N. , CHUA PATRICK S. K. , AULIA ANDY UTAMA , YEO PETER L. P. 
Published: May 2005

Diagnosis of diabetes is usually achieved by obtaining a single reading of blood-glucose concentration value from the Oral Glucose Tolerance Test (OGTT). However, the result itself is inadequate in providing insight into the glucose-regulatory etiology of diabetes disease disorder, which is important for treatment purposes. The objective of this project was to conduct clinical simulation and parametric identification of OGTT model for diagnosis of diabetic patient, so as to classify diabetic or at-risk patients into different categories, depending on the nature of their blood-glucose tolerance response to oral injestion of a bolus of glucose. In other words, the patient classification depends on how the blood-glucose concentration varies with time; i.e. how much does it peak, how long does it takes to reach its peak value, how fast does it return to the fasting value, etc. during the oral glucose tolerance test. To represent this blood-glucose concentration [y(t)] regulatory dynamics, the model selected is a second-order differential equation, [Formula: see text] of blood-glucose concentration response to a bolus of ingested glucose Gδ(t). This model was then applied to the test subjects by making the model solution-expression for y(t) match the monitored clinical data of blood-glucose concentration at different time intervals, through clinical simulation and parametric identification. The solutions obtained from the model to fit the clinical data were different for normal and diabetic test subjects. The clinical data of "normal" subjects could be simulated by means of an under-damped solution of the model, as: y(t) = (G/ω)e-ωt sin ωt. The data of "diabetic" patients needed to be simulated by means of an over-damped solution of the model, as: y(t) = (G/ω)e-At sin hωt, where G represents the magnitude of the impulse input Gδ(t) to the model (in gms of glucose per litre of blood pool volume), ω is the damped oscillatory frequency of the model, wn is the natural frequency of the system and [Formula: see text]. In order to facilitate differential diagnosis, we developed a non-dimensional diabetic index (DI) expressed as: [Ay max Td/GT max ]. This index can be used to facilitate the diagnosis of diabetes as well as for assessing the risk to becoming diabetic.
Effect of NF-κB Constitutive Activation on Proliferation and Apoptosis of Gastric Cancer Cell Lines
Authors: Li Q. , Yu Y.-Y. , Zhu Z.-G. , Ji Y.-B. , Zhang Y. , Liu B.-Y. , Chen X.-H. , Lin Y.-Z. 
Published: May 2005

<i>Objective:</i> To observe whether there is constitutive activation of nuclear transcription factor ĸB (NF-ĸB) and its effect on proliferation and apoptosis of human gastric cancer cell lines. <i>Methods:</i> Nuclear/cytoplasmic protein expression of NF-ĸB was analyzed by Western blot in four different gastric cancer cell lines. Trans AM<sup>TM</sup> NF-ĸB p65 Kit was used for detecting the difference of p65 activity. The effect of PDTC (pyrrolidine dithiocarbamate), a specific inhibitor of NF-ĸB on the proliferation of gastric cancer cells, was measured by MTT (3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium bromide) method. The apoptotic rates of AGS and SGC-7901 gastric cancer cell lines were measured with flow cytometer (FCM) after treatment by PDTC. <i>Results:</i> The constitutive activations of NF-ĸB were identified in four gastric cancer cell lines. The expression of activated subunit of p50 was lower in AGS cell line, and higher in MKN28, MKN45 and SGC-7901 cell lines. The expression of activated subunit of p65 was lower in MKN28 and MKN45 cell lines, and higher in AGS and SGC-7901 cell lines. Both the activity of NF-ĸB and the cell proliferation were significantly inhibited in experimental group treated by PDTC, compared with control groups (p < 0.01). An increased apoptotic rate and a decreased proliferating activity were observed after the gastric cancer cells were exposed to PDTC for 24 h. <i>Conclusions:</i> These results suggested that the constitutive activation and the protein expression of NF-ĸB are different in gastric cancer cell lines. PDTC can inhibit NF-ĸB activity and cell proliferation, which related to an increased cell apoptosis. The results disclosed that NF-ĸB could be a potential therapeutic target for solid tumor therapy.
Palestinian Political Identities during the Post-Oslo Period: A Case Study of Generation Effects in a West Bank Refugee Camp
Authors: LYBARGER Loren D. 
Published: May 2005

English The first Intifada (1987-1993) split Palestinian society in the West Bank and Gaza Strip into two camps, one secular-nationalist, the other Islamist. The author examines the new identities that formed as a result of this split in a Bethlehem-area refugee camp. Drawing on the concepts of event as structurally transforming process, socio-political milieu, and Mannheimian generation units, he shows how the first Intifada gave rise to a generational dialectic that in turn produced new religio-political orientations. He concludes by suggesting an extension of the Mannheimian framework to take into account the dynamic effects of generation-unit tensions for collective solidarities. French Depuis la première Intifada (1987-1993), les Palestiniens se sont divisés en nationalistes et islamistes. Dans une étude d'un camp de réfugiés à Bethléem, l'auteur analyse les nouvelles identités qui sont apparues à la suite de cette division. Il explique la déstabilisation de ces identités en s'appuyant sur le concept d'événement comme processus de transformation structurelle du milieu sociopolitique et des unités générationnelles comprises au sens de Mannheim. Il montre comment la première Intifada a engendré une dialectique générationnelle, laquelle a produit des orientations religieuses et politiques nouvelles. Il termine en suggérant une extension du cadre théorique de Mannheim qui permette de prendre en compte les effets dynamiques de ces tensions dans une perspective de maintien des solidarités.