bluuebunny/crossref_metadata_2025 huggingface dataset:
Behavior of trickle‐bed air biofilter for toluene removal: Effect of non‐use periods
Authors: Kim Daekeun , Cai Zhangli , Sorial George A.
Published: April 2005

A laboratory‐scale trickle bed air biofilter (TBAB) packed with synthetic, inorganic media for microbial attachment was used for toluene removal from an air stream. Three experimental strategies—including backwashing as the active biomass control and two non‐use periods (starvation, which represents a period without toluene loading, and stagnant, which reflects no flow)—were considered in this study. The non‐use periods can be considered as another means of biomass control for low VOC loadings (0.70 and 1.41 kg COD/m3·day), whereas at high VOC loading (>3.52 kg COD/m3·day) backwashing is deemed essential to remove the excess biomass accumulation in the biofilter. As the toluene loading rate was increased, a considerably longer reacclimation period was unavoidable for biofilter performance to reach the 99% removal for all experimental strategies (backwashing, starvation, and stagnant). Because the biofilter response was strongly dependent on the active biomass in the system, biofilter response after the non‐use periods was significantly different from that after backwashing. © 2005 American Institute of Chemical Engineers Environ Prog, 2005
Magnetic tracing at Abu Sir (land of forgotten pyramids), northern Egypt
Authors: Abdallatif Tareq Fahmy , Abd‐All Esmat Mohamed , Suh Mancheol , Mostafa Mohamad Reem , El‐Hemaly Ibrahim Aly
Published: April 2005

An Erratum has been published for this article in Geoarchaeology 20(6) 2005, 659.

An integrated magnetic study was conducted at Abu Sir, a locality in northern Egypt also known as the “Land of the Forgotten Pyramids.” Two magnetic tools were applied over an area of 25,600 m2 in order to trace and detect hidden archaeological features near the Temple of the Sun. The acquisition of the magnetic data was initiated by measuring the magnetic susceptibility of the topsoil samples collected within the entire study area. This was followed by a gradiometer survey to measure the vertical gradient of the geomagnetic field over a restricted area of 14,400 m2. The magnetic susceptibility results are characterized by high values in the middle of the study area and a small extension of high values to the southwest. This pattern may indicate the presence of ritual monuments. The magnetic susceptibility measurements identified regions of interest to be targeted during the gradiometer survey. The gradiometer results revealed the existence of numerous archaeological features of different shapes and sizes composed of mud bricks. These features may represent tombs, burial rooms, and dissected walls, and all of them probably belong to the 5th Dynasty of pharaohs. The depth of the expected buried archaeological features was estimated from the gradiometer results and is about 1.2 m for deep features and 0.42 m for shallow features. © 2005 Wiley Periodicals, Inc.
Lightning strikes and prehistoric ovens: Determining the source of magnetic anomalies using techniques of environmental magnetism
Authors: Maki David
Published: April 2005

Techniques of environmental magnetism were used to examine soil samples from a North American archaeological site in an effort to determine the source of magnetic field gradient anomalies. Testing revealed the source of one anomaly to be lightning‐induced remanent magnetization (LIRM). This anomaly had initially been identified as a possible archaeological feature, but excavations were unable to identify a visible source. LIRM appears to be a relatively common source of anomalous signal on archaeological sites and may often be misinterpreted in magnetic imagery. Thermoremanent magnetization (TRM) was also documented and quantified in soil from archaeological hearths at the site, as were changes in the ferrimagnetic mineral concentration and coercivity spectra resulting from high‐temperature enhancement within the hearths. © 2005 Wiley Periodicals, Inc.
Magnetometric investigations of stone constructions within large ancient barrows of Denmark and Crimea
Authors: Smekalova Tatyana , Voss Olfert , Smekalov Sergej , Myts Victor , Koltukhov Sergej
Published: April 2005

Two examples of magnetic investigations of large barrows in Denmark and Crimea (Ukraine) are presented. The magnetic field over the Danish barrows containing megalithic graves results from the superposition of many different dipole anomalies from granite boulders. The magnetic map revealed a corridor and a chamber of a barrow in Draaby, which are adjacent to a similar, previously excavated feature. A circular wall of smaller stones, which surrounds the two chambers and corridors, is clearly visible on the magnetic map. The limestone building material used for the internal construction of the Scythian barrows in Crimea is practically nonmagnetic, while the soil in these regions has a significant magnetic susceptibility (about 10−100 ×10−5 ISO). This makes it possible to identify stone structures by their negative anomalies on magnetic maps. Each of the three large barrows is surrounded by a circular negative anomaly that is 50 m in diameter. The anomaly is caused by walls (cromlechs) inside the barrows. Within each barrow, a long negative anomaly (up to −20 nT) that starts at the cromlech and leads toward the center of the barrow is an indication of a rectangular stone construction inside the barrow (side crypt). The central part of each barrow is characterized by a positive or a negative anomaly, which reflects the state of preservation of the central chamber. © 2005 Wiley Periodicals, Inc.
A methodology for rapid archaeological site documentation using ground‐penetrating radar and terrestrial photogrammetry
Authors: Lorenzo Henrique , Arias Pedro
Published: April 2005

This study demonstrates how a combination of ground‐penetrating radar (GPR) and terrestrial photogrammetry were used at an archaeological site in Vigo, Spain to quickly detect and document the remains of two megalithic tombs. An investigation was necessary because the tombs were uncovered during the construction of a new highway. A total station survey was conducted to develop a digital terrain model (DTM) of the study area. Then, a GPR investigation of shallow subsoil was carried out with a 900‐MHz antenna. Radar imaging enabled the mapping of two groups of very shallow reflectors, and the excavation revealed a layer of stones with some vertical gravestones at both sites. Each structure forms a megalithic tomb similar to the barrows of Western Europe. Finally, a close‐range photogrammetric study was conducted to obtain an accurate metric document. The exhaustive documentation enabled a fine‐scaled 3D reconstruction of tombs, thereby creating a detailed record of a site which no longer exists. © 2005 Wiley Periodicals, Inc.
Effect of certain bioactive plant extracts on clinical isolates of β‐lactamase producing methicillin resistant Staphylococcus aureus
Authors: Aqil Farrukh , Khan M. Sajjad A. , Owais Mohd , Ahmad Iqbal
Published: April 2005

Ethanolic extracts and some fractions from 10 Indian medicinal plants, known for antibacterial activity, were investigated for their ability to inhibit clinical isolates of β‐lactamase producing methicillin‐resistant Staphylococcus aureus (MRSA) and methicillin‐sensitive S. aureus (MSSA). Synergistic interaction of plant extracts with certain antibiotics was also evaluated. The MRSA test strains were found to be multi‐drug resistant and also exhibited high level of resistance to common β‐lactam antibiotics. These strains produced β‐lactamases, which hydrolyze one or other β‐lactam antibiotics, tested. The extract of the plants from Camellia sinensis (leaves), Delonix regia (flowers), Holarrhena antidysenterica (bark), Lawsonia inermis (leaves), Punica granatum (rind), Terminalia chebula (fruits) and Terminalia belerica (fruits) showed a broad‐spectrum of antibacterial activity with an inhibition zone size of 11 mm to 27 mm, against all the test bacteria. The extracts from the leaves of Ocimum sanctum showed better activity against the three MRSA strains. On the other hand, extracts from Allium sativum (bulb) and Citrus sinensis (rind) exhibited little or no activity, against MRSA strains. The antibacterial potency of crude extracts was determined in terms of minimum inhibitory concentration (MIC) by the tube dilution method. MIC values, of the plant extracts, ranged from 1.3 to 8.2 mg/ml, against the test bacteria. Further, the extracts from Punica granatum and Delonix regia were fractionated in benzene, acetone and methanol. Antibacterial activity was observed in acetone as well as in the methanol fractions. In vitro synergistic interaction of crude extracts from Camellia sinensis, Lawsonia inermis, Punica granatum, Terminalia chebula and Terminalia belerica was detected with tetracycline. Moreover, the extract from Camellia sinensis also showed synergism with ampicillin.

TLC of the above extracts revealed the presence of major phytocompounds, like alkaloids, glycosides, flavonoids, phenols and saponins. TLC‐bioautography indicated phenols and flavonoids as major active compounds. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Role of white rot fungus Funalia trogii in detoxification of textile dyes
Authors: Apohan Elif , Yesilada Ozfer
Published: April 2005

Toxic and genotoxic effects of the textile dyes on organisms suggest the need for remediation of dyes before discharging them into the environment. For this reason, the ability of Funalia trogii pellets to detoxify textile dyes was investigated and evaluated. Although, textile dyes are toxic substances for many microorganisms, the pellets were able to decolorize and detoxify the azo dyes used. Astrazon Blue and Red dyes inhibit growth of F. trogii and S. aureus on solid medium in a concentration dependent manner. The toxicity of these dyes on a fungus, F. trogii and a bacterium, S. aureus was significantly decreased after pretreatment with fungal pellets. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interference of laccase in determination of cellobiose dehydrogenase activity of Pleurotus ostreatus (Florida) using dichlorophenol indophenol as the electron acceptor
Authors: Saha Tanima , Chakraborty Tapas Kumar , Saha Rina , Das Nirmalendu , Mukherjee Mina
Published: April 2005

Pleurotus ostreatus (Florida), ITCC 3308 produces ∼9.0 U/ml extracellular cellobiose dehydrogenase (CDH) in cellulose medium after 7 days of growth. However, no activity could be detected if the assay was done with cellobiose as the substrate and 2,6‐dichlorophenol indophenol (DPIP) as the electron acceptor in absence of any laccase inhibitor. Kinetic study showed that Vmax/Km value was very high for rDPIP (reduced 2,6‐dichlrophenol indophenol) oxidation by laccase. Oxygen consumption rate of rDPIP oxidation by the enzyme was found to be highest among all the tested substrates. The present study indicated that rDPIP was a good substrate for laccase. Therefore, caution is needed to measure CDH activity by monitoring DPIP reduction in a system where laccase is likely to be present. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deamination of adenosine by extracts of Penicillium politans NRC‐510
Authors: Elshafei Ali M. , Mohamed Latifa A. , Ali Nadia H.
Published: April 2005

Cell‐free extracts of nitrate‐grown Penicillium politans NRC‐510 could catalyze the hydrolytic deamination of adenosine to inosine maximally at pH 6.0 and 45 °C. However the same extracts could not catalyze the N‐glycosidic bond cleavage of adenosine at pH 4.0, 6.0 and 8.0. Incubation of the extracts at 55 °C for 30 minutes caused about 31% loss in activity whereas incubation of the extracts at 60 °C for 15 minutes caused a complete loss of enzyme activity. Results indicated the absence of the involvement of sulfhydryl groups in the catalytic site of adenosine deaminase. The enzyme is inhibited by ethylene diamine tetraacetate indicating that adenosine deaminase is a metalloenzyme. MnCl2 and MgCl2 had a remarkable activating effect, whereas HgCl2, CaCl2 and ZnSO4 showed an inhibitory effect on enzyme activity. Dialyzing the extracts for 24 hours significantly increase deaminase activity by about 33%. The apparent Km value was calculated for adenosine and found to be 3.63 × 10–3 M, which indicates high affinity of adenosine deaminase for its substrate adenosine. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
δ‐Aminolevulinic acid biosynthesis in Ustilago maydis
Authors: Schneegurt Mark A.
Published: April 2005

A biosynthetic precursor of tetrapyrroles, δ‐aminolevulinic acid (ALA), can be formed via two pathways: enzymatic condensation of glycine and succinyl‐CoA by ALA synthase in animal mitochondria and some fungi, and the C5 pathway converting glutamate to ALA in plants, algae, archaea, and most bacteria. The two pathways are distinguishable using specifically radiolabeled compounds. The C1 of glutamate is lost during conversion to succinate in the TCA cycle, and the C2 of glycine is lost during conversion to acetyl‐CoA on the way to glutamate. Desalted high‐speed supernatants of Ustilago maydis sporidia extracts were assayed using specifically radiolabeled substrates. A significant amount of radiolabel was incorporated into ALA from 2‐[14C]glycine. No radiolabel was incorporated into ALA from 1‐[14C]glutamate. These results indicate that the basidiomycete yeast, Ustilago maydis, has active ALA synthase. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The oxidative stress response of the yeast Candida intermedia to copper, zinc, and selenium exposure
Authors: Fujs Štefan , Gazdag Zoltán , Poljšak Borut , Stibilj Vekoslava , Milačič Radmila , Pesti Miklós , Raspor Peter , Batič Martin
Published: April 2005

The yeast Candida intermedia, as a model organism, was used to examine the links between the metal ions exposure, reactive oxygen species generation and oxidative stress response. To estimate intracellular peroxide and superoxide levels, the fluorescence indicators dihydrorhodamine 123 and dihydroethidium were used, respectively. Antioxidant defence systems were investigated by measuring the activity of catalase, glutathione peroxidase and superoxide dismutase and the content of reduced glutathione. Altered superoxide, peroxide, glutathione levels, and the catalase activity were perceived after the treatment with copper. In the samples treated with selenium and zinc the altered peroxide and superoxide levels, and the glutathione peroxidase activity were perceived. The results indicate that the tolerance of the yeast C. intermedia to different metal ions was correlated with the reactive oxygen species generation in the cells and with the efficiency of antioxidative defence systems. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of a thermostable extracellular lipase from Bacillus megaterium AKG‐1
Authors: Sekhon Anurag , Dahiya Neetu , Tiwari Ram P. , Hoondal Gurinder S.
Published: April 2005

An extracellular lipase isolated from Bacillus megaterium AKG‐1 had an optimum activity at 55 °C/pH 7.0. It retained 100% activity at 50 °C for 30 min with a half life of 30 min at 70 °C. A 20–70% increase in lipase activity was observed in presence of acetone (20% v/v), DMSO (20% v/v) and isopropanol (10% v/v). The enzyme activity was 92, 98 and 107% after 24 h, on treatment with 10% (v/v) acetone, benzene and isopropanol respectively. Deoxycholic acid, sodium deoxycholate, lithocholic acid, rhamnolipid, Brij 52 and cholic acid stimulated the lipase activity by 76, 36, 24, 24, 23.6 and 13%, respectively. Addition of reducing agents like sodium sulphite, sodium metabisulphite and L‐cysteine‐HCl, at 10 mM concentration stimulated lipase activity by 127, 146 and 150% respectively. The lipase appeared to show enantioselectivity in hydrolyzing racemic 3‐acetoxy‐β‐lactam as it hydrolyzed only the (+) enantiomer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sensitivity of different Zygomycetes to the Penicillium chrysogenum antifungal protein (PAF)
Authors: Galgóczy László , Papp Tamás , Leiter Éva , Marx Florentine , Pócsi István , Vágvölgyi Csaba
Published: April 2005

The effects of the Penicillium. chrysogenum low molecular mass antifungal protein (PAF) on selected fungal species belonging in the Zygomycetes were investigated. A total of 21 fungal isolates from 15 different genera (Absidia, Actinomucor, Cokeromyces, Gilbertella, Micromucor, Mortierella, Mucor, Mycotypha, Rhizomucor, Rhizopus, Saksenaea, Syncephalastrum, Thamnostylum, Umbelopsis and Zygorhynchus) were tested. The inhibitory potentials of PAF at 50 µg ml–1 on the germination of the sporangiospores and at 6.25–50 µg ml–1 on the hyphal extension were examined on different culture media. From among the fungi regarded as opportunistic human and/or animal pathogens, PAF exhibited inhibitory effects against Absidia, Mortierella, Rhizomucor and Rhizopus species. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Export channel dynamics: an empirical investigation
Authors: Benito Gabriel R.G. , Pedersen Torben , Petersen Bent
Published: April 2005

We investigate the dynamics of export channel arrangements by modelling foreign operation method decisions as the interplay between factors that motivate switches and factors that deter them. Our model extends previous analyses by looking simultaneously at (1) no change of channel arrangement, (2) replacements of foreign intermediaries (within‐mode shifts), and (3) integration of the sales function abroad (between‐mode shifts). We use a multinomial logit model on longitudinal data from a sample of Danish exporters that had entered foreign markets through intermediaries. The results suggest that the decision to carry out within‐mode shifts (i.e. to replace an existing intermediary) is driven by a different set of factors than the decision to switch to another foreign operation mode (i.e. to in‐house operations). Copyright © 2005 John Wiley & Sons, Ltd.
Analysis of aberrant somatic hypermutation (SHM) in non‐Hodgkin's lymphomas of patients with chronic HCV infection
Authors: Libra Massimo , Capello Daniela , Gloghini Annunziata , Laura Pasqualucci , Berra Eva , Cerri Michaela , Gasparotto Daniela , Franca Stivala , De Re Valli , Gaidano Gianluca , Carbone Antonino
Published: April 2005

Hepatitis C virus (HCV) and aberrant somatic hypermutation (SHM) have each been suggested to contribute to the development of B‐cell non‐Hodgkin's lymphoma (NHL). The incidence of PIM‐1, PAX‐5, RhoH/TTF, and c‐MYC mutations in tumour biopsy specimens from 32 HCV‐infected B‐cell NHL patients was analysed to determine whether the extent of aberrant SHM among these patients differed from that previously reported for HCV‐negative B‐cell NHL patients. Mutation of PIM‐1, PAX‐5, RhoH/TTF, and c‐MYC was detected in 4 (13%), 5 (16%), 4 (13%), and 4 (13%) of 32 samples, respectively. In HCV‐positive B‐cell NHL patients, the frequency of aberrant SHM was lower than that already found in HCV‐negative B‐cell NHL patients. This indicates that, unlike B‐cell lymphomas from HCV‐negative patients, aberrant SHM may not contribute significantly to malignant transformation in HCV‐associated B‐cell lymphomas. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Expression profiling of murine intestinal adenomas reveals early deregulation of multiple matrix metalloproteinase (Mmp) genes
Authors: Martinez Cristina , Bhattacharya Sumit , Freeman Tom , Churchman Michael , Ilyas Mohammad
Published: April 2005

Initiation of intestinal tumours occurs as a consequence of aberrant Wnt signalling. This causes altered expression of a number of genes which provides the mechanistic basis of neoplastic change in normal epithelium. In order to identify these genes, expression profiles of normal intestinal mucosa and intestinal adenomas from multiple intestinal neoplasia (Min) mice were compared. A total of 116 genes were found to show significant changes in expression in adenomas compared with normal mucosa. Functional classification of these genes clearly identified the biological processes of cellular adhesion and matrix remodelling to be profoundly affected. Notably, three members of the matrix metalloproteinase (Mmp) gene family (Mmp10, Mmp13, and Mmp14) were consistently up‐regulated in tumour tissue. To extend these data, expression of 17 Mmp genes was defined using quantitative reverse transcriptase‐polymerase chain reaction (Q‐RT‐PCR). Several Mmp genes were profoundly up‐regulated and every tumour showed overexpression of at least four Mmp genes. These results underscore the probable importance of interactions between the intestinal epithelium and stroma in early tumour development. Furthermore, the inferred role of Mmps at the adenomatous stage of tumourigenesis suggests that this may represent the optimal therapeutic window for the use of Mmp antagonists as anti‐cancer agents. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Differential expression and response to anti‐TNFα treatment of infiltrating versus resident tissue macrophage subsets in autoimmune arthritis
Authors: De Rycke Leen , Baeten Dominique , Foell Dirk , Kruithof Elli , Veys Eric M , Roth Johannes , De Keyser Filip
Published: April 2005

Synovial macrophages play a pivotal role in the pathogenesis of chronic autoimmune arthritis by contributing to local inflammation and tissue damage and are therefore a primary target for therapeutic intervention. The aim of the present study was to investigate in more detail the relative contribution of different synovial macrophage subsets with potentially different inflammatory or anti‐inflammatory functions by analysing the two most frequent forms of human autoimmune arthritis, spondyloarthropathy (SpA) and rheumatoid arthritis (RA). Both infiltrating macrophages from peripheral blood expressing myeloid‐related proteins (MRP) 8 and 14, and resident tissue macrophages expressing CD163 were abundant in inflamed synovium. Whereas the global number of synovial macrophages was similar in both diseases, infiltrating macrophages were increased in the RA lining layer in contrast with resident tissue macrophages, which were more frequently observed in SpA. Soluble MRP8/MRP14 complexes, which were secreted locally in the joint during the infiltration process, were increased in the serum of arthritis patients and, in contrast with soluble CD163 shed from resident tissue macrophages, correlated well with global inflammatory parameters. Treatment in vivo with anti‐TNFα had a rapid and pronounced effect on the infiltration of MRP‐positive macrophages into tissues, as evidenced by histopathological analysis and serum MRP8/MRP14 levels. Taken together, these data support an important role for infiltrating versus resident tissue macrophages in human autoimmune synovitis and indicate that macrophage products such as soluble MRP8/MRP14 complexes are valuable biomarkers for the experimental and clinical monitoring of specific disease mechanisms in vivo. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Linear viscoelastic properties of high‐density polyethylene/polyamide‐6 blends extruded in the presence of ultrasonic oscillations
Authors: Li Jiang , Liang Mei , Guo Shaoyun , Kuthanová Vanda , Hausnerová Berenika
Published: April 2005

Blends of high‐density polyethylene (HDPE) and polyamide‐6 (PA6) were produced by ultrasonic extrusion. Ultrasonic irradiation leads to degradation of polymers and in situ compatibilization of blends as confirmed by variations in linear viscoelastic properties. The results showed that the effect of ultrasonic irradiation on dynamic rheological properties depends on the composition and experimental temperature. At the same time, the relationship between storage modulus and loss modulus indicated the effect of ultrasonic irradiation on compatibility of HDPE/PA6 blends. Based on an emulsion model, the interfacial tension between the matrix and the dispersed phase was predicted. The data obtained showed that ultrasonic irradiation can decrease the interfacial tension and then enhance the compatibility of HDPE/PA6 blends. This finding was consistent with our previous work. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1260–1269, 2005
Professional preparation of individuals who provide genetic counseling services
Authors: James Delores C. S. , Crandall Lee A. , Rienzo Barbara A. , Trottier Ralph W.
Published: April 2005

An unprecedented increase has occurred in demand for genetic counseling services during the current decade. This study examined the complex issue of who currently provides genetic counseling services and the professional preparation of these personnel. A self‐administered questionnaire was mailed to 325 genetic counseling professionals in the southeastern United States who were members of the Southeast Regional Genetics Group (SERGG), National Society of Genetic Counselors, or American Society of Human Genetics States; 204 completed the questionnaire (63%). Seventy percent of respondents were female and 30% were male. Thirty percent of respondents held MD degrees; nine physicians held PhD degrees. Most physicians were male. Thirty‐two percent of respondents held master's degrees in genetic counseling; five counselors held PhD degrees. Twenty‐three percent of respondents were nurses; eight nurses held master's degrees. Three percent of respondents were social workers. Individuals with other degrees, such as an associate of science in medical technology and a doctoral degree in education, also provided genetic counseling. Genetic counseling typically involved a team effort, consisting mainly of physicians and genetic counselors. Most respondents reported college coursework in human genetics, supervised training, and seminar/workshop training. Thirty percent reported college coursework in counseling techniques, supervised training, and seminar/workshop training. Policy recommendations are offered concerning professional preparation of genetic counselors.
Diffuse solar radiation and associated meteorological parameters in India
Authors: Bhattacharya A. B. , Kar S. K. , Bhattacharya R.
Published: April 2005

Abstract. Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with some meteorological parameters. The monthly values of diffuse radiation and the monthly ratios of diffuse to global solar radiation have been examined, with a special emphasis in relation to the noise level of atmospherics at Calcutta in the very low frequency band. The results exhibit some definite seasonal changes which appear to be in close agreement with one another.
THE DOCTRINE OF LEGITIMATE EXPECTATIONS: PROSPECTS AND PROBLEMS IN CONSTITUTIONAL LITIGATION IN SOUTH AFRICA
Authors: Ikhariale M. A.
Published: April 2005

One of the outstanding features of the South African Constitution is the well-articulated concept of administrative justice. It is to be expected that a modern constitutional state with an enormous social reconstruction programme like that of post-apartheid South Africa must have a sophisticated mechanism for the maintenance of administrative justice. The immediate past experience of apartheid under which the administrative process was devoted to the victimization of a large section of the population has also meant that every constitutional means possible in the arduous task of social reconstruction must be deployed towards the declared objective of the evolution of a humane and just administrative process. It was therefore not surprising that the post-apartheid constitutions considered the availability of administrative justice for citizens as one of their foremost civil liberties. Under the common law, the concept of administrative justice is generally associated with the notion of natural justice. Recent developments, however, have tended to narrow the concept down to the idea of fairness. The most remarkable proof of this development is the emergence of the doctrine of legitimate expectations, under which the courts have been able to come to the aid of persons who would have in previous situations been unable to obtain redress in matters where the application of administrative discretion is of paramount importance.
THE ACCOMMODATION OF RELIGIOUS DIVERSITY IN SOUTH AFRICA AGAINST THE BACKGROUND OF THE CENTRALITY OF THE EQUALITY PRINCIPLE IN THE NEW CONSTITUTIONAL DISPENSATION
Authors: Henrard Kristin
Published: April 2005

South Africa is often characterized as a highly religious country since many South Africans consider their religious beliefs to be central to their lives. Although religion is widely believed to be a “non-issue”, these strong religious identifications might, however, play a role in the apparent ethnic resurgence. Consequently, the religious diversity of South Africa should be appropriately accommodated in the post-apartheid regime so as to prevent religion-based conflict.
RECENT DEVELOPMENTS
Authors: Murray Rachel
Published: April 2005

In July 2000, several months after the United Nations produced an independent report citing the failures of the organization in relation to the 1994 genocide in Rwanda (the Carlsson Report), the Organization of African Unity's (OAU) Summit in Lomé, Togo, was presented with a several-hundred page report from its International Panel of Eminent Personalities to Investigate the 1994 Genocide in Rwanda and the Surrounding Events (IPEP). While the Carlsson Report focused exclusively on the responsibility of the UN, the IPEP had a wide mandate to examine the situation which led to the genocide and the failures of the Genocide Convention, and to make recommendations for redress and action to prevent it happening again. Similarly, although the UN document does acknowledge that the OAU failed to prevent the genocide, attributing this to a lack of resources and political will, the IPEP Report is more forceful in its condemnation of the influence and responsibility of several European states and the USA. The Panel considered the part played by these states as essential to an understanding of the genocide, despite the fact that its intention was not to determine the guilt of various actors. This note provides a descriptive summary of the contents of the Report.
LAW AND SOCIAL CHANGE: A SOCIO-LEGAL ANALYSIS OF NIGERIA'S CORRUPT PRACTICES AND OTHER RELATED OFFENCES ACT, 2000
Authors: Ocheje Paul D.
Published: April 2005

This article is in two parts. The first part analyses, and largely applauds, the Corrupt Practices and Other Related Offences Act, 2000, the latest in a series of enactments designed to curb corruption in Nigeria over the last thirty years. The second part looks at the social environment within which corruption operates. It points out that in the past the environment was such that anti-corruption measures were bound to fail, but it concludes, in optimistic vein, that the recent return to civilian rule has created a climate in which the new Act is likely to have an effect in the fight against corruption.
NON-DISCRIMINATION ON THE GROUNDS OF RACE IN SOUTH AFRICA - WITH SPECIAL REFERENCE TO THE PROMOTION OF EQUALITY AND PREVENTION OF UNFAIR DISCRIMINATION ACT
Authors: Vogt Grete S.
Published: April 2005

The Promotion of Equality and Prevention of Unfair Discrimination Act in South Africa seeks to make the constitutional prohibition of discrimination as effective as possible. The achievement of this aim is, however, likely to be frustrated by several factors, including the legacy of apartheid, deficiencies in the formal statutory guarantees and the judicial interpretation of these, and the lack of effective enforcement mechanisms. As a result, the attempt to clamp down on racial discrimination has removed from the constitutional guarantee much of its potential force.
STATUTE NOTE
Authors: Coldham Simon
Published: April 2005

LAND ACQUISITION AMENDMENT ACT, 2000 (ZIMBABWE)

Since Zimbabwe became independent in 1980 the issue of land reform and,
in particular, the issue of land acquisition and redistribution has seldom been
off the political agenda. For the first ten years of independence there were
constitutional constraints on the acquisition of land for resettlement purposes,
but the National Land Policy of 1990 set out plans for an accelerated programme
of resettlement. In order to achieve its ambitious targets the government of
Zimbabwe saw the need to strengthen its powers of compulsory acquisition both
by amending section 16 of the Constitution (which provided strong protection
against the compulsory acquisition of property) and by enacting the Land
Acquisition Act to provide a statutory basis for the new policy. These reforms
were extremely controversial both inside and outside the country and a clause
excluding the right to fair compensation for expropriated land was dropped
partly in response to international pressure.
Culture and language learning: teaching, research and scholarship
Authors: Byram Michael , Feng Anwei
Published: April 2005

This review of work on the cultural dimension of language teaching updates one from 1986 and shows that there has been a considerable growth in interest since then. The focus has been largely on the elaboration of conceptual models and theories and the development of teaching and training approaches; much less effort has been devoted to empirical research investigating the impact of such developments and building up a body of knowledge.
The A-factor regulatory cascade that leads to morphological development and secondary metabolism in Streptomyces
Authors: Ohnishi Y. , Horinouchi S.
Published: April 2005

A-factor (2-isocapryloyl-3R-hydroxymethyl-γ-butyrolactone) is a chemical signalling molecule, or microbial hormone, that triggers aerial mycelium formation and secondary metabolism in Streptomyces griseus. A-factor pro- duced in a growth-dependent manner switches on the transcription of adpA, encoding a transcriptional activator, by binding to ArpA, the A-factor receptor protein, which has bound to the adpA promoter, and dissociating the bound ArpA from the DNA. AdpA then activates a number of genes of various functions required for morphological development and secondary metabolism, forming an AdpA regulon. ArpA, which belongs to the TetR family, contains a helix–turn–helix DNA-binding motif in its N-terminal portion and an A-factor-binding pocket (5 Å (0.5 nm) diameter and 20 Å (2 nm) long) in its C-terminal portion, as implied by X-ray crystallography of CprB, an ArpA homologue. The ligand pocket, which can accommodate an entire A-factor-type molecule of γ-butyrolactone, is completely embedded in the C-terminal portion. Upon binding A-factor, a long helix connecting the A-factor-binding and ligand-binding domains is relocated, as a result of which the DNA-binding helix moves outside, resulting in dissociation from DNA. AdpA, which belongs to the AraC/XylS family, contains a ThiJ/PfpI/DJ-1-like dimerization domain in its N-terminal portion and an AraC/XylS-type DNA-binding domain in its C-terminal portion. For transcriptional activation, AdpA can bind to various positions with respect to the transcriptional start points of the target genes and sometimes to multiple sites. We show here how A-factor triggers secondary metabolism and morphological development in S. griseus, with emphasis on the two key transcriptional factors, ArpA and AdpA, in the A-factor regulatory cascade.
Caries lesion development and biofilm composition responses to varying demineralization times and sucrose exposures
Authors: Fontana M. , Haider A. , González-Cabezas C.
Published: April 2005

The aim of this research was to study the effect of varying incubation times and sucrose exposures on lesion development and biofilm composition using a multi-species biofilm caries model. Two studies were conducted. In study 1, enamel specimens were divided into four groups, inoculated with a mixed overnight culture of Streptococcus mutans, Lactobacillus casei, Actinomycesnaeslundii, Streptococcusparasanguis and Streptococcussalivarius, and exposed to circulating trypticase soy broth + 5% (w/v) sucrose (TSBS; 30 min, three times per day (3 × /day)) and a mineral washing solution containing 0.25 p.p.m. fluoride (22.5 h/day) for 2, 5, 6 or 8 days. In study 2, additional enamel specimens were divided into four groups and exposed to the same biofilm for 7 days, but with variations in the feeding schedule: TSBS 3×/day for 5 min, TSBS 3×/day for 15 min, TSBS 3 × /day for 30 min, or TSBS 3×/day for 30 min + 1×/day for 15 min. At the end of each study, bacterial colonization counts and lesion size were determined. In study 1, specimens developed significantly deeper carious lesions with longer demineralization time (average lesion depth was 52.16 μm, 67.86 μm, 84.91 μm, and 99.97 μm, respectively, for 2, 5, 6, and 8 days). In study 2, there was no significant difference in size between the lesions developed at feeding schedules of 3 × /day for 5 or 15 min. Lesions exposed to longer (30 min) and more frequent feeding schedules (4×/day) were significantly larger than the other groups. In both studies, all five bacterial species were able to colonize the enamel and were present in all groups at the end of the experiments, with predominance of lactobacilli over S. mutans. In conclusion, larger lesions were observed with increased incubation time and more frequent feeding schedules, with small variations in biofilm composition.
Biocomplexity in the oral cavity – the basics of structure in supragingival bacterial communities
Authors: Palmer R. J. , Diaz P. I. , Kolenbrander P. E.
Published: April 2005

The human oral microbial ecosystem is one of the best characterized and highly complex bacterial communities known. It is estimated that about 600 bacterial species exist in the mouth and that 85% of those are currently known at the molecular (16 S rRNA) level. The major bacterial physiologies occurring in the oral cavity have been known for many years, and knowledge exists of the distribution of organisms in time (as plaque accumulates) and in space (different environments within the mouth). However, only rudimentary data are available on interactions between the bacterial species. It is precisely these interactions that, along with the interactions of the developing community with its human host, must drive the succession of genera that is observed to occur. In the reductionist scientific approach to studying such interactions, disrupted plaque is used to isolate single organisms, and interactions between these organisms are examined by recombining the organisms ex situ. Lessons learned from these in vitro studies can be applied to understand empirical observations made in vivo. However, this approach begins with the primary assumption that the chosen interaction does in fact occur in vivo. The accessibility and the well-characterized nature of the oral ecosystem presents an opportunity for approaching the problem from the opposite direction; one can capture a community very early in development in vivo, then apply in vitro methods to sort out the interactions within that community. This latter approach begins with a set of organisms known to interact in vivo. A combination of both approaches should yield robust microbiological data suitable for in silico modeling and analyses.
Quantitative analyses of Streptococcus mutans biofilms with quartz crystal microbalance, microjet impingement and confocal microscopy
Authors: Kreth J. , Hagerman E. , Tam K. , Merritt J. , Wong D. T. W. , Wu B. M. , Myung N. V. , Shi W. , Qi F.
Published: April 2005

Microbial biofilm formation can be influenced by many physiological and genetic factors. The conventional microtiter plate assay provides useful but limited information about biofilm formation. With the fast expansion of the biofilm research field, there are urgent needs for more informative techniques to quantify the major parameters of a biofilm, such as adhesive strength and total biomass. It would be even more ideal if these measurements could be conducted in a real-time, non-invasive manner. In this study, we used quartz crystal microbalance (QCM) and microjet impingement (MJI) to measure total biomass and adhesive strength, respectively, of S. mutans biofilms formed under different sucrose concentrations. In conjunction with confocal laser scanning microscopy (CLSM) and the COMSTAT software, we show that sucrose concentration affects the biofilm strength, total biomass, and architecture in both qualitative and quantitative manners. Our data correlate well with previous observations about the effect of sucrose on the adherence of S. mutans to the tooth surface, and demonstrate that QCM is a useful tool for studying the kinetics of biofilm formation in real time and that MJI is a sensitive, easy-to-use device to measure the adhesive strength of a biofilm.
Differential tolerance of Pseudomonas putida biofilm and planktonic cells to desiccation
Authors: van de Mortel M. , Chang W.-S. , Halverson L. J.
Published: April 2005

The desiccation tolerance of Pseudomonas putida strain mt-2 cells within intact unsaturated biofilms and cells cultivated in liquid media was examined. Since as soils dry there can be an increase in the solute potential and reductions in nutrient availability, we also assessed the effect of the solute and matric (low-water-content) components of the total water potential, and nutrient availability on cell survival. Biofilms were cultivated in model laboratory systems that can simulate the matric and solute components of the total water potential and the poorly mixed nature of unsaturated habitats. Desiccation stress was imposed by exposing biofilm and planktonic cells to environments with controlled relative humidities. Our results show that biofilm cells are more tolerant to air drying than are planktonic cells, and tolerance is enhanced when there is an adequate supply of nutrients available to the cells. We provide evidence suggesting that a major factor contributing to desiccation sensitivity is the matric stress itself rather than solute stress and that matric stress is inherently more stressful to P. putida than is the thermodynamically equivalent solute stress.
Detailed three-dimensional analysis of structural features of Myxococcus xanthus fruiting bodies using confocal laser scanning microscopy
Authors: Lux R. , Li Y. , Lu A. , Shi W.
Published: April 2005

Myxococcus xanthus is a motile soil bacterium with complex social behaviors. Upon starvation, a developmental program is initiated that results in cellular aggregation and fruiting body formation. This process requires the exopolysaccharide (EPS) component of the extracellular matrix. With prolonged starvation, a part of the cells within a fruiting body die, while the other cells differentiate into spores. Extensive genetic and biochemical information has been generated that elucidates this interesting developmental process. Little is known, however, about the detailed three-dimensional structural features of native fruiting bodies or the EPS and distribution of live/dead cells (spores) within these structures. In this study, changes in the three-dimensional architecture of fruiting bodies and the distribution of the extracellular matrix within the fruiting bodies during the developmental process were investigated using a gfp-expressing M. xanthus strain and carbohydrate-specific lectins or monoclonal antibodies in combination with confocal laser scanning microscopy. The extracellular matrix was found to form a scaffold within the fruiting body structure. Furthermore, using a bacterial viability staining assay, the distribution of live/dead cells within fruiting bodies was examined at different times. The majority of live cells were found to localize at the outer layer of a mature fruiting body, with dead cells underneath.
A modelling study of the activity and structure of biofilms in biological reactors
Authors: Xavier J. B. , Picioreanu C. , van Loosdrecht M. C. M.
Published: April 2005

In spite of the large range of morphologies observed for biofilms, there is strong experimental and theoretical evidence that the complex nature of biofilm structure dynamics is primarily a consequence of the effect of environmental conditions on biofilm development. It has been observed from the operation of industrial and laboratory-scale biofilm reactors that the structure of biofilms results from a balance of the detachment forces and the regimen of transport of a growth-limiting substrate. The overall performance of biofilm reactors is intrinsically dependent on biofilm morphology. The spatial distribution of the diverse dissolved and particulate components through the biofilm matrix and the shape of its external surface influence the rates of the occurring bioconversions, and structure also influences the stability of the biofilm in terms of resistance to mechanical stress. Individual-based modelling (IbM) of biofilms structure dynamics is used here to unify observations from the operation of biofilm reactors by simulating biofilm growth under variable detachment forces and mass transport regimens for a growth-limiting substrate. The IbM is a bottom-up approach, where the global system behaviour is derived from the local interactions of multiple elements acting independently. Transport and reaction of a solute species, local microbial growth rates and the effect of external detachment forces applied to the biofilm are modelled using differential approaches. Simulations carried out in two-dimensional space using this model illustrate a range of biofilm morphologies that emerge from different reactor operation parameters, reproducing trends observed experimentally. Comparison of multi-dimensional modelling results with those obtained using one-dimensional approaches enforces the need to use multi-dimensional modelling to predict properties that derive from the spatial biofilm structure.
Advances in mathematical modeling of biofilm structure
Authors: Picioreanu C. , Xavier J. B. , van Loosdrecht M. C. M.
Published: April 2005

Mathematical modeling of spatial biofilm structure has been in development for the past 10 years, its main goal being to derive the dynamics of biofilm structure from first-principle descriptions of the various physical, chemical and biological processes involved in biofilm formation. Early efforts described development of unrestricted monospecies consortia, often considering diffusion and reaction of a single solute species. Multi-dimensional modeling of biofilms has presently reached a stage where multi-species systems with any number of bacterial and solute species, reactions and arbitrary detachment scenarios may be readily implemented using a general-purpose software framework introduced recently. The present work presents motivations for the mathematical modeling of biofilm structure and provides an overview on major contributions to this field from pioneering efforts using cellular automata (CA) to more recent methods using the preferred individual-based modeling (IbM). Recent examples illustrate how biofilm models can be used to study the microbial ecology in: (a) development of multi-species nitrifying biofilms with anammox bacteria, (b) interspecies hydrogen transfer in anaerobic digestion methanogenic consortia, (c) competition between flock-formers and filamentous bacteria influenced by environmental conditions and its effect on morphology of activated sludge flocs, and (d) a two-species biofilm system with structured biomass describing extracellular polymeric substances (EPS) and internal storage compounds. As recent efforts from direct comparison of structure predicted by three-dimensional modeling with that observed by confocal laser scanning microscopy imaging of biofilms grown in laboratory flow cells show a good agreement of predicted structures, multi-dimensional modeling approaches presently constitute a mature and established methodology to enhance our understanding of biofilm systems.