bluuebunny/crossref_metadata_2025 huggingface dataset:
Fish and ostracod remains from the Santos Basin (Cretaceous to Recent), Brazil
Authors: Giles Miller C. , Richter Martha , Do Carmo Dermeval A.
Published: November 2002

For the first time, ichthyoliths are described from the Santos sedimentary basin, offshore southern Brazil. Isolated teeth, dermal scales and the first documented otoliths from Cretaceous (Albian) to Recent cuttings from five wells are described. The following groups are represented: Chondrichthyans: Triakidae, Carcharhinidae; Ginglymostomatidae: ?Ginglymostomasp., Lamnidae indet., Scyliorhinidae; Osteichthyans: Teleostei; Myctophiidae:Diaphusaff.splendidussp. complex,Diaphusspp.,Diaphuscf.garmani,Ceratoscopelusaff.warmingii; Sternoptychidae:Valenciennellus tripunctulatus, teeth of indeterminate Teleostei. The majority of these ichthyofossils represent extant forms, known to occur in the Atlantic Ocean, and are of potential value for stratigraphical correlations between oil‐yielding basins in the region. Ostracods are not well preserved but can be identified to generic level indicating marine environments. The ostracod faunas offer potential for intrabasinal correlation in the Eocene and Oligocene. Copyright © 2002 John Wiley & Sons, Ltd.
Reductionism and the search for structure–function relationships in antibody molecules
Authors: Van Regenmortel Marc H. V.
Published: November 2002

One of the claims of reductionism is that it can explain all the features of living systems by an analysis of their physico‐chemical constituents. Such a claim disregards the existence in biological systems of emergent properties that do not exist in their isolated components but which allow autonomous organisms to be directively organized in a self‐regulated and integrated manner. It is not possible to describe biological systems adequately without using functional language that is meaningless in the physical sciences. The description of biological functions is also an essential part of immunology and functional explanations are more useful than causal explanations also in this discipline. Since causality is not a relation between a material object and an event, the structure of an antibody cannot be the cause of its binding activity. When structure–function relationships are analysed, the search should be for correlations rather than for causal relations. Methods used to find correlations between the atomic structure of antibody binding sites and their binding activity are mostly based on mutagenesis studies. Since the effect of any mutation depends on the molecular context, it is usually very difficult to predict the effects of multiple mutations on antibody function. Our knowledge of the molecular basis of antigen–antibody recognition has led to the expectation that it may be possible to develop new vaccines using molecular design principles. Such unwarranted hopes arise because of a confusion between antigenicity and immunogenicity. Although knowledge of antibody structure is of little use in vaccine design, it may help to develop therapeutic inhibitors and antibodies effective in the passive immunotherapy of viral infection Copyright © 2002 John Wiley & Sons, Ltd.
An investigation into the interference rejection capability of a linear array in a wireless communications system
Authors: Durrani Salman , Bialkowski Marek E.
Published: November 2002

The suitable use of an array antenna at the base station of a wireless communications system can result in improvement in the signal‐to‐interference ratio (SIR). In general, the SIR is a function of the direction of arrival of the desired signal and depends on the configuration of the array, the number of elements, and their spacing. In this paper, we consider a uniform linear array antenna and study the effect of varying the number of its elements and inter‐element spacing on the SIR performance. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 445–449, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10634
A novel wideband antenna package design with a compact spatial‐notch filter for wireless applications
Authors: Yeo Junho , Mittra Raj
Published: November 2002

This paper presents a compact package, comprising a wideband antenna with a compact spatial‐notch filter, useful for RF applications requiring a high rate of data transfer. Fractal concepts are employed to help reduce the package to almost half the normal size, and to realize a much sharper band‐stop than would be possible with a conventional filter. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 455–460, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10637
An inverse problem of normal incidence TE plane‐wave scattering and the method of lines
Authors: Hooshyar M. A.
Published: November 2002

The direct and inverse problems of normally incident TE plane‐wave scattering by perfectly conducting cylindrical structures with arbitrary cross sections are considered. It is shown that application of the method of lines results in an efficient procedure for calculating the scattering amplitude and also for determining the shape of cylindrical structures if the electromagnetic scattering amplitude is given. To illustrate the procedure, some realistic numerical examples are presented. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 486–491, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10645
Broadband conical printed quadrifilar helical antenna with integrated feed network
Authors: Yang Shiwen , Tan Soon Hie , Gan Yeow Beng , See Chun Wee
Published: November 2002

A new approach to designing a broadband printed quadrifilar helical antenna (PQHA) is presented. The printed wire is conical in shape, while the feed network is directly integrated underneath the antenna. The entire system is designed using Ansoft HFSS. Good agreement with the experimental results is obtained. The impedance and axial ratio bandwidth values are greater than 32.4% and 18.5%, respectively. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 491–493, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10646
A fast and practical approach to the determination of junction temperature and thermal resistance for BJT/HBT devices
Authors: Ooi Ban Leong , Chen Bo , Lin Fujiang , Kooi Pang Shyan , Hui Chi So
Published: November 2002

A simple, robust, accurate method to extract the thermal resistance of BJT/HBT devices is proposed, which only needs the measured device DC I‐V characteristics at room temperature. No optimization is needed to extract the thermal resistance. The proposed method is verified using a variety of BJT/HBT devices. Compared to the measured results taken from both CW DC measurements and isothermal measurements, the extracted values using our method is in excellent agreement with the conventional method. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 499–502, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10648
Efficient multiwavelength generation of Brillouin/erbium fiber laser at 1600‐nm region
Authors: Harun S. W. , Tamchek N. , Poopalan P. , Ahmad H.
Published: November 2002

An efficient Brillouin/erbium fiber laser, which operates in the 1600‐nm (L‐band) region, is demonstrated for potential applications in future dense‐wavelength division multiplexing communication systems. The laser configuration consists of an L‐band EDFA (to enable L‐band amplification) where two 3‐dB couplers take a portion of the generated BEFL signal and re‐inject it into the single‐mode fiber in order to seed a cascaded BEFL line in the same direction as the first BEFL line. An efficient BEFL can be obtained by recycling backward a 1550‐nm‐band amplified spontaneous emission as a secondary pump source for the unpumped EDF in the L‐band EDFA section. As a result, the lasing threshold is reduced and slope efficiency is improved. A stable and strong laser comb of up to five lines with 10‐GHz spacing has been obtained with a Brillouin pump of 4.8 mW and a 980‐nm pump of 92 mW. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 35: 506–508, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10650
Domain analysis in information science
Authors: Hjørland Birger
Published: November 2002

What kind of knowledge is needed by information specialists working in a specific subject field like medicine, sociology or music? What approaches have been used in information science to produce kinds of domain‐specific knowledge? This article presents 11 approaches to domain analysis. Together these approaches make a unique competence for information specialists. The approaches are: producing literature guides and subject gateways; producing special classifications and thesauri; research on indexing and retrieving specialities; empirical user studies; bibliometrical studies; historical studies; document and genre studies; epistemological and critical studies; terminological studies, LSP (languages for special purposes), discourse studies; studies of structures and institutions in scientific communication; and domain analysis in professional cognition and artificial intelligence. Specific examples and selective reviews of literature are provided, and the strengths and drawbacks of each of these approaches are discussed.
The role of subject literature in scholarly communication
Authors: Andersen Jack
Published: November 2002

In this article an epistemological interpretation of the role of subject literature in scholarly communication shall be proposed. Such an interpretation will focus on the epistemological dimension of communicating knowledge through literature and how this is achieved through discursive and rhetorical means. It will be argued that library and information science (LIS) theory on scholarly communication can be supplemented and strengthened by this interpretation. By establishing a social epistemology of subject literature the article contributes with a sketch of a coherent theory of scholarly literature explaining the epistemological and communicative division of labor between the various types of subject literature. Such a theory is in line with the current revival of social epistemology in LIS. The article is structured into three main sections. The first section will outline an epistemological position that pays particular attention to knowledge acquired through social interaction in general, and through interaction with written texts in particular. The works of the later Wittgenstein and Ludwik Fleck will be used as the theoretical frameworks. Having established this epistemological framework, the second section will outline what is considered to be the main types of subject literature, with emphasis on their discursive and rhetorical functions in scholarly communication. The third section will synthesize the two other sections into a sketch of a theory that will be labeled the social epistemology of subject literature and point to some implications for LIS research of this theory.
An investigation into the learning needs of managers in internationalising small and medium‐sized enterprises
Authors: Anderson Valerie , Boocock Grahame , Graham Stuart
Published: November 2002

This paper is concerned with the learning needs of managers in SMEs that seek to become progressively international. A particular focus of attention is the informal learning practices that occur within the economic and social networks utilised by managers in this sector. Using both qualitative and quantitative approaches to data collection, the paper investigates the challenges perceived by managers engaged (or seeking to engage) in international activity. The results suggest three main areas of challenge: first, the early “pre‐internationalisation” stage, when decisions about “whether”, “where” or “how” to internationalise are taken; secondly, the development of longer‐term planning processes and business systems to cope with the consequences of the initial internationalisation decision; thirdly, the challenge of regulatory issues and the need to secure payment and manage foreign intermediaries. Further areas of learning need, which depend on the significance of international business for the firm, are also indicated. Existing structures, cultures and approaches to management can be maintained for many SMEs that undertake some limited international activity. Where international business is a more important factor, however, managers need to develop cultural appreciation and empathy to underpin their expertise and consolidate their market position. Indeed, sustained international development may require a significant reorienting of the business, underpinned by management and organisational learning to develop an appropriate international “mind‐set” that supports the effective development of relationships with stakeholders in different countries.
Birth and growth in new metal‐based manufacturing and business service firms in Finland
Authors: Littunen Hannu
Published: November 2002

This study examined factors influencing the growth of new firms in metal‐based manufacturing and business services in Finland over the three first years of their operation. The factors affecting the growth of a new firm were found in the start‐up phase, in the characteristics of the entrepreneur and of the firm, and in the firm’s environment. Growth was especially explained by the know‐how and changes in the strategic behaviour of the entrepreneur and by the firm’s environment. New firmshad equal chances for growth irrespective of their locality. Instead, growth was affected by changes in a firm’s competitive situation, and, especially in the more developed service centres, growth was dependent on a firm’s expanding its market area in the first three years of operation. The results also clearly indicated that in a small specialist firm personal relationships formed an important part of the entrepreneur’s management capabilities.
Internet perception and use: a gender perspective
Authors: Heimrath Rosie , Goulding Anne
Published: November 2002

This paper reports êndings of a study undertaken in late 1999 which aimed to identify and analyse the differences in use, by gender, of the Internet. A review of the literature of the differences in use, by gender, of computers generally is provided. The study involved students at Loughborough University and members of the public at libraries in Loughborough and Slough. The results of this (fairly limited) study show that female use, interest and conêdence in using the Internet is high but, in comparison with male respondents the females had not taken to the Internet as rapidly.
Health information kiosk use in health organisations: the views of the health professionals
Authors: Nicholas David , Williams Peter , Huntington Paul
Published: November 2002

A series of in‐depth one to one and group interviews were undertaken with health professionals and surgery practice managers in medical locations where a touch screen information kiosk was available for use by patients. The purpose of these interviews was to provide context and understanding for the kiosk log data that was being gathered that provided data on number and length of use sessions, pages viewed and age and gender of users. The interviews were also concerned with issues beyond those raised by the logs ‐ principally the benefits and problems inherent in providing health information ‘online’ and the impact of electronic information for patients on the work of the medical practitioner. The reasons why kiosks were purchased and the extent to which expectations were met were also areas of interest. Results showed that disproportionately high use of the kiosk by children, identified by the log data, could be explained in a number of ways. Medical practitioners spoke of helping children both use the system for school projects and access pages on behalf of parents and grandparents. Inappropriate use, however, was also reported by practice managers. A number of factors cited by professionals, such as poor IT skills and cultural barriers, help explain low use by the 55‐74 age group. A resurgence of interest amongst the over 74s, however, remains a mystery awaiting the next stage of the fieldwork, when patients are interviewed directly. Extensive encouragement by staff to encourage patient use may account for some of the condition specific pages accessed, by all age groups. Nurses tended to be far more pro‐active than doctors, and saw many health‐related benefits in referring patients to the kiosk. By contrast, doctors saw the system in very practical ways ‐ praising its space saving potential, for example, not enthusing about its possible value to patients in health terms. Practice managers and others with responsibility for the maintenance of the system were unhappy with the extra work they were required to undertake, and complained about children ‘playing’ and about printer and other problems.
Information search process of lawyers: a call for ’just for me’ information services
Authors: Kuhlthau C.C. , Tama S.L.
Published: November 2002

The study reported in this paper is part of a programme of ongoing research based on the model of the Information Search Process (ISP) developed in a series of prior studies by Kuhlthau. This study sought to gain a better understanding of the variety of tasks that involve lawyers as a particular group of information workers, how they use information to accomplish their work, and the role mediators play in their process of information seeking and use. Findings revealed that these lawyers frequently were involved in complex tasks that required a constructive process of interpreting, learning and creating. To accomplish these complex tasks, they preferred printed texts over computer databases primarily because computer databases required well‐specified requests and did not offer an option for examining a wide range of information at one time. These lawyers called for an active potential role for mediators in ‘just for me’ services. ‘Just for me’ services would encompass designing systems to provide a wider range of access more compatible with the process of construction, applying and developing principles of classification that would offer a more uniform system for organising and accessing files, and providing direction in filtering the overwhelming amount of information available on electronic resources.
Results from a web impact factor crawler
Authors: Thelwall Mike
Published: November 2002

Web impact factors, the proposed web equivalent of impact factors for journals, can be calculated by using search engines. It has been found that the results are problematic because of the variable coverage of search engines as well as their ability to give significantly different results over short periods of time. The fundamental problem is that although some search engines provide a functionality that is capable of being used for impact calculations, this is not their primary task and therefore they do not give guarantees as to performance in this respect. In this paper, a bespoke web crawler designed specifically for the calculation of reliable WIFs is presented. This crawler was used to calculate WIFs for a number of UK universities, and the results of these calculations are discussed. The principal findings were that with certain restrictions, WIFs can be calculated reliably, but do not correlate with accepted research rankings owing to the variety of material hosted on university servers. Changes to the calculations to improve the fit of the results to research rankings are proposed, but there are still inherent problems undermining the reliability of the calculation. These problems still apply if the WIF scores are taken on their own as indicators of the general impact of any area of the Internet, but with care would not apply to online journals.
Information and digital literacies: a review of concepts
Authors: Bawden David
Published: November 2002

The concepts of ‘information literacy’ and ‘digital literacy’ are described, and reviewed, by way of a literature survey and analysis. Related concepts, including computer literacy, library literacy, network literacy, Internet literacy and hyper‐literacy are also discussed, and their relationships elucidated. After a general introduction, the paper begins with the basic concept of ‘literacy’, which is then expanded to include newer forms of literacy, more suitable for complex information environments. Some of these, for example library, media and computer literacies, are based largely on specific skills, but have some extension beyond them. They lead togeneral concepts, such as information literacy and digital literacy which are based on knowledge, perceptions and attitudes, though reliant on the simpler skills‐based literacies
Men’s tailored jackets: objective measurement and consumer perception
Authors: Ball C. , Fairclough D. , Ruckman J.E.
Published: November 2002

To investigate consumers’ perceptions of appearance and handle of the chest area and the lapel in men’s tailored jackets, both objective measurement using FAST and subjective assessment utilising semi‐structured interview were employed. It was found that objective measurement provides insufficient information to predict the tailorability if reliance is placed purely upon properties obtained from shell fabrics. Use of the fabric and interlining laminates, however, provides better prediction of tailorability, especially those aspects associated with appearance and shape retention. It was also found that objective measurement results do not agree with the subjective assessment results, particularly with regard to the subjective assessment of the female interviewees. It is suggested that thought should be given to devising a method of evaluating objective measurement results suitable to fabric and interlining laminates that can also take account of market trends directly related to consumer perception.
Mycobacterium bovisBCG Response Regulator Essential for Hypoxic Dormancy
Authors: Boon Calvin , Dick Thomas
Published: November 2002

Obligately aerobic tubercle bacilli are capable of adapting to survive hypoxia by developing into a nonreplicating or dormant form. Dormant bacilli maintain viability for extended periods. Furthermore, they are resistant to antimycobacterials, and hence, dormancy might play a role in the persistence of tuberculosis infection despite prolonged chemotherapy. Previously, we have grown dormantMycobacterium bovisBCG in an oxygen-limited Wayne culture system and subjected the bacilli to proteome analysis. This work revealed the upregulation of the response regulator Rv3133c and three other polypeptides (α-crystallin and two “conserved hypothetical” proteins) upon entry into dormancy. Here, we replaced the coding sequence of the response regulator with a kanamycin resistance cassette and demonstrated that the loss-of-function mutant died after oxygen starvation-induced termination of growth. Thus, the disruption of this dormancy-induced transcription factor resulted in loss of the ability of BCG to adapt to survival of hypoxia. Two-dimensional gel electrophoresis of protein extracts from the gene-disrupted strain showed that the genetic loss of the response regulator caused loss of the induction of the other three dormancy proteins. Thus, the upregulation of these dormancy proteins requires the response regulator. Based on these two functions, dormancy survival and regulation, we named the Rv3133c genedosRfor dormancy survival regulator. Our results provide conclusive evidence that DosR is a key regulator in the oxygen starvation-induced mycobacterial dormancy response.
Requirement for IscS in Biosynthesis of All Thionucleosides in
Escherichia coli
Authors: Lauhon Charles T.
Published: November 2002

Escherichia coli
tRNA contains four naturally occurring nucleosides modified with sulfur. Cysteine is the intracellular sulfur source for each of these modified bases. We previously found that the
iscS
gene, a member of the
nifS
cysteine desulfurase gene family, is required for 4-thiouridine biosynthesis in
E. coli
. Since IscS does not bind tRNA, its role is the mobilization and distribution of sulfur to enzymes that catalyze the sulfur insertion steps. In addition to
iscS
,
E. coli
contains two other
nifS
homologs,
csdA
and
csdB
, each of which has cysteine desulfurase activity and could potentially donate sulfur for thionucleoside biosynthesis. Double
csdA csdB
and
iscS csdA
mutants were prepared or obtained, and all mutants were analyzed for thionucleoside content. It was found that unfractionated tRNA isolated from the
iscS
mutant strain contained <5% of the level of sulfur found in the parent strain. High-pressure liquid chromatography analysis of tRNA nuclease digests from the mutant strain grown in the presence of [
35
S]cysteine showed that only a small fraction of 2-thiocytidine was present, while the other thionucleosides were absent when cells were isolated during log phase. As expected, digests from the
iscS
mutant strain contained 6-
N
-dimethylallyl adenosine (i
6
A) in place of 6-
N
-dimethylallyl-2-methylthioadenosine and 5-methylaminomethyl uridine (mnm
5
U) instead of 5-methylaminomethyl-2-thiouridine. Prolonged growth of the
iscS
and
iscS csdA
mutant strains revealed a gradual increase in levels of 2-thiocytidine and 6-
N
-dimethylallyl-2-methylthioadenosine with extended incubation (>24 h), while the thiouridines remained absent. This may be due to a residual level of Fe-S cluster biosynthesis in
iscS
deletion strains. An overall scheme for thionucleoside biosynthesis in
E. coli
is discussed.
The Cysteine Desulfurase IscS Is Required for Synthesis of All Five Thiolated Nucleosides Present in tRNA from
Salmonella enterica
Serovar Typhimurium
Authors: Nilsson Kristina , Lundgren Hans K. , Hagervall Tord G. , Björk Glenn R.
Published: November 2002

Deficiency of a modified nucleoside in tRNA often mediates suppression of +1 frameshift mutations. In
Salmonella enterica
serovar Typhimurium strain TR970 (
hisC3737
), which requires histidine for growth, a potential +1 frameshifting site, CCC-CAA-UAA, exists within the frameshifting window created by insertion of a C in the
hisC
gene. This site may be suppressed by peptidyl-tRNA
Procmo5UGG
(cmo
5
U is uridine-5-oxyacetic acid), making a frameshift when decoding the near-cognate codon CCC, provided that a pause occurs by, e.g., a slow entry of the tRNA
Glnmnm5s2UUG
(mnm
5
s
2
U is 5-methylaminomethyl-2-thiouridine) to the CAA codon located in the A site. We selected mutants of strain TR970 that were able to grow without histidine, and one such mutant (
iscS51
) was shown to have an amino acid substitution in the
l
-cysteine desulfurase IscS. Moreover, the levels of all five thiolated nucleosides 2-thiocytidine, mnm
5
s
2
U, 5-carboxymethylaminomethyl-2-thiouridine, 4-thiouridine, and
N
-6-(4-hydroxyisopentenyl)-2-methylthioadenosine present in the tRNA of
S. enterica
were reduced in the
iscS51
mutant. In logarithmically growing cells of
Escherichia coli
, a deletion of the
iscS
gene resulted in nondetectable levels of all thiolated nucleosides in tRNA except
N
-6-(4-hydroxyisopentenyl)-2-methylthioadenosine, which was present at only 1.6% of the wild-type level. After prolonged incubation of cells in stationary phase, a 20% level of 2-thiocytidine and a 2% level of
N
-6-(4-hydroxyisopentenyl)-2-methylthioadenosine was observed, whereas no 4-thiouridine, 5-carboxymethylaminomethyl-2-thiouridine, or mnm
5
s
2
U was found. We attribute the frameshifting ability mediated by the
iscS51
mutation to a slow decoding of CAA by the tRNA
Glnmnm5s2UUG
due to mnm
5
s
2
U deficiency. Since the growth rate of the
iscS
deletion mutant in rich medium was similar to that of a mutant (
mnmA
) lacking only mnm
5
s
2
U, we suggest that the major cause for the reduced growth rate of the
iscS
deletion mutant is the lack of mnm
5
s
2
U and 5-carboxymethylaminomethyl-2-thiouridine and not the lack of any of the other three thiolated nucleosides that are also absent in the
iscS
deletion mutant.
Bacteriophage HP2 of
Haemophilus influenzae
Authors: Williams Bryan J. , Golomb Miriam , Phillips Thomas , Brownlee Joshua , Olson Maynard V. , Smith Arnold L.
Published: November 2002

Temperate bacteriophages effect chromosomal evolution of their bacterial hosts, mediating rearrangements and the acquisition of novel genes from other taxa. Although the
Haemophilus influenzae
genome shows evidence of past phage-mediated lateral transfer, the phages presumed responsible have not been identified. To date, six different
H. influenzae
phages are known; of these, only the HP1/S2 group, which lyosogenizes exclusively Rd strains (which were originally encapsulated serotype d), is well characterized. Phages in this group are genetically very similar, with a highly conserved set of genes. Because the majority of
H. influenzae
strains are nonencapsulated (nontypeable), it is important to characterize phages infecting this larger, genetically more diverse group of respiratory pathogens. We have identified and sequenced HP2, a bacteriophage of nontypeable
H. influenzae
. Although related to the fully sequenced HP1 (and even more so to the partially sequenced S2) and similar in genetic organization, HP2 has a few novel genes and differs in host range; HP2 will not infect or lysogenize Rd strains. Genomic comparisons between HP1/S2 and HP2 suggest recent divergence, with new genes completely replacing old ones at certain loci. Sequence comparisons suggest that
H. influenzae
phages evolve by recombinational exchange of genes with each other, with cryptic prophages, and with the host chromosome.
Characterization of a Fourth Tungsten-Containing Enzyme from the Hyperthermophilic Archaeon
Pyrococcus furiosus
Authors: Roy Roopali , Adams Michael W. W.
Published: November 2002

Pyrococcus furiosus
grows optimally near 100°C using peptides and carbohydrates as carbon sources, and it reduces elemental sulfur (S
0
), if present, to H
2
S. Tungsten (W), an element rarely used in biology, is required for optimal growth, and three different tungsten-containing enzymes have been previously purified from this organism. They all oxidize aldehydes of various types and are thought to play primary roles in the catabolism of sugars or amino acids. Here, the purification of a fourth tungsten-containing enzyme, termed WOR 4, from cell extracts of
P. furiosus
grown with S
0
is described. This was achieved by monitoring through multiple chromatography steps the W that is not associated with the three characterized tungstoenzymes. The N-terminal sequence of WOR 4 and the approximate molecular weight of its subunit determined electrophoretically (69,000) correspond to the product of an ORF (PF1961,
wor4
) present in the complete genome sequence of
P. furiosus
. WOR 4 is a homodimer and contains approximately one W, three Fe, three or four acid-labile sulfide, and one Ca atom per subunit. The visible and electron paramagnetic resonance spectra of the oxidized and reduced enzyme indicate the presence of an unusual iron-sulfur chromophore. WOR 4 does not oxidize aliphatic or aromatic aldehydes or hydroxy acids, nor does it reduce keto acids. Consistent with prior microarray data, the protein could not be purified from
P. furiosus
cells grown in the absence of S
0
, suggesting that it may have a role in S
0
metabolism.
Repression of Glutamate Dehydrogenase Formation in
Klebsiella aerogenes
Requires Two Binding Sites for the Nitrogen Assimilation Control Protein, NAC
Authors: Goss Thomas J. , Janes Brian K. , Bender Robert A.
Published: November 2002

In
Klebsiella aerogenes
, the
gdhA
gene codes for glutamate dehydrogenase, one of the enzymes responsible for assimilating ammonia into glutamate. Expression of a
gdhAp-lacZ
transcriptional fusion was strongly repressed by the nitrogen assimilation control protein, NAC. This strong repression (>50-fold under conditions of severe nitrogen limitation) required the presence of two separate NAC binding sites centered at −89 and +57 relative to the start of
gdhA
transcription. Mutants lacking either or both of these sites lost the strong repression. The distance between the two sites was less important than the face of the helix on which they lay. Insertion or deletion of 10 bp between the sites had little effect on the strong repression, but insertion of 5 bp or deletion of either 5 or 15 bp decreased the repression significantly. We propose that the strong repression of
gdhAp-lacZ
expression requires an interaction between the NAC molecules bound at the two sites. A weaker repression of
gdhAp-lacZ
expression (about threefold) required only the NAC site centered at −89. This weaker repression appears to result from NAC's ability to prevent the action of a positive effector the target of which overlaps the NAC binding site centered at −89. Point mutations and deletions of this region result in the same threefold reduction in
gdhAp-lacZ
expression as the presence of NAC at this site.
The
Escherichia coli gabDTPC
Operon: Specific γ-Aminobutyrate Catabolism and Nonspecific Induction
Authors: Schneider Barbara L. , Ruback Stephen , Kiupakis Alexandros K. , Kasbarian Hillary , Pybus Christine , Reitzer Larry
Published: November 2002

Nitrogen limitation induces the nitrogen-regulated (Ntr) response, which includes proteins that assimilate ammonia and scavenge nitrogen. Nitrogen limitation also induces catabolic pathways that degrade four metabolically related compounds: putrescine, arginine, ornithine, and γ-aminobutyrate (GABA). We analyzed the structure, function, and regulation of the
gab
operon, whose products degrade GABA, a proposed intermediate in putrescine catabolism. We showed that the
gabDTPC
gene cluster constitutes an operon based partially on coregulation of GabT and GabD activities and the polarity of an insertion in
gabT
on
gabC
. A Δ
gabDT
mutant grew normally on all of the nitrogen sources tested except GABA. The unexpected growth with putrescine resulted from specific induction of
gab
-independent enzymes. Nac was required for
gab
transcription in vivo and in vitro. Ntr induction did not require GABA, but various nitrogen sources did not induce enzyme activity equally. A
gabC
(formerly
ygaE
) mutant grew faster with GABA and had elevated levels of
gab
operon products, which suggests that GabC is a repressor. GabC is proposed to reduce nitrogen source-specific modulation of expression. Unlike a wild-type strain, a
gabC
mutant utilized GABA as a carbon source and such growth required σ
S
. Previous studies showing σ
S
-dependent
gab
expression in stationary phase involved
gabC
mutants, which suggests that such expression does not occur in wild-type strains. The seemingly narrow catabolic function of the
gab
operon is contrasted with the nonspecific (nitrogen source-independent) induction. We propose that the
gab
operon and the Ntr response itself contribute to putrescine and polyamine homeostasis.
Identification and Localization of the Gene Cluster Encoding Biosynthesis of the Antitumor Macrolactam Leinamycin in
Streptomyces atroolivaceus
S-140
Authors: Cheng Yi-Qiang , Tang Gong-Li , Shen Ben
Published: November 2002

Leinamycin (LNM), produced by
Streptomyces atroolivaceus
, is a thiazole-containing hybrid peptide-polyketide natural product structurally characterized with an unprecedented 1,3-dioxo-1,2-dithiolane moiety that is spiro-fused to a 18-member macrolactam ring. LNM exhibits a broad spectrum of antimicrobial and antitumor activities, most significantly against tumors that are resistant to clinically important anticancer drugs, resulting from its DNA cleavage activity in the presence of a reducing agent. Using a PCR approach to clone a thiazole-forming nonribosomal peptide synthetase (NRPS) as a probe, we localized a 172-kb DNA region from
S. atroolivaceus
S-140 that harbors the
lnm
biosynthetic gene cluster. Sequence analysis of 11-kb DNA revealed three genes,
lnmG
,
lnmH
, and
lnmI
, and the deduced product of
lnmI
is characterized by domains characteristic to both NRPS and polyketide synthase (PKS). The involvement of the cloned gene cluster in LNM biosynthesis was confirmed by disrupting the
lnmI
gene to generate non-LNM-producing mutants and by characterizing LnmI as a hybrid NRPS-PKS megasynthetase, the NRPS module of which specifies for
l
-Cys and catalyzes thiazole formation. These results have now set the stage for full investigations of LNM biosynthesis and for generation of novel LNM analogs by combinatorial biosynthesis.
Alcaligin Siderophore Production by
Bordetella bronchiseptica
Strain RB50 Is Not Repressed by the BvgAS Virulence Control System
Authors: Brickman Timothy J. , Armstrong Sandra K.
Published: November 2002

A previous study found that alcaligin siderophore production by
Bordetella bronchiseptica
strain RB50 is Bvg repressed. In contrast, we report that alcaligin production by RB50 does not require Bvg phenotypic phase modulation and that isogenic Bvg(Con) and Bvg
−
phase-locked mutants both produce alcaligin in response to iron starvation.
Pneumoproteinaemia: a new perspective in the assessment of lung disorders
Authors: Hermans C , Bernard A
Published: November 2002

Here we make the hypothesis that the determination of the concentration of lung specific secretory proteins in serum or pneumoproteinaemia could be used in the evaluation of lung disorders with a similar utility as proteinuria in kidney diseases involving the glomeruli. Human and experimental data indicate that comparable structural and functional features govern the passage of proteins across the lung epithelium/blood barrier and the glomerular filter. The concentrations in serum of some lung-specific secretory proteins, such as the bronchiolar Clara cell 16 kDa protein (CC16) and alveolar surfactant-associated proteins A and B (SP-A and SP-B, respectively), might be used to assess the integrity of the bronchoalveolar/blood barrier known to be disrupted in many lung disorders. In addition, if this barrier is intact or slightly compromised, these proteins might serve as peripheral markers to detect changes in secretory epithelial cells in the lung.
Breathing patterns in children with craniofacial dysostosis and hindbrain herniation
Authors: Gonsalez SL , Thompson D , Hayward R , Lane R
Published: November 2002

In the past few years, hindbrain herniation has become recognized as a frequent feature of the child with syndromic craniofacial dysostosis. The clinical significance of hindbrain herniation in these disorders is unclear. Abnormalities of respiratory control have frequently been reported. The aim of the present study was to document the incidence of obstructive and central respiratory abnormalities during sleep in craniofacial syndromes with hindbrain herniation. We performed cardiorespiratory sleep studies during unsedated night-time sleep in a group of 13 children. Hindbrain herniation was confirmed by magnetic resonance imaging (MRI) and ranged 1.5-26.9 mm below the cranial base. Sleep studies revealed central respiratory pauses associated with important reduction of the arterial oxygen saturation (Sa,O2) in only two of 13 cases (minimum Sa,O2 86% and 87%). In contrast 10 of 13 children had some degree of upper airway obstruction (four mild, three moderate and three severe). Of the remaining three children, two had previous long-term tracheostomies. Changes in the breathing pattern were proportional to the severity of the obstruction and comprised increased respiratory efforts and arterial oxygen desaturation. Infrequent mixed apnoeas were observed in five patients, and their severity reflected the severity of the obstructive component. In conclusion, obstruction of the upper airways was the predominant sleep-related respiratory problem in this group of patients. Hindbrain herniation was not associated with a high incidence of central sleep apnoea.
Nasal prongs in the detection of sleep-related disordered breathing in the sleep apnoea/hypopnoea syndrome
Authors: Ballester E , Badia  , Hernandez L , Farre R , Navajas D , Montserrat JM
Published: November 2002

Conventional systems to monitor oronasal flow in sleep studies have traditionally relied on a thermistor signal. Our study was designed to verify whether nasal prongs (NP) connected to a pressure transducer could improve respiratory events detection in patients with sleep apnoea/hypopnoea syndrome (SAHS) compared to traditional systems. Sleep episodes from a 2 h conventional polysomnographic record plus NP signal obtained at random from eight patients (age: mean(+/-SD) 53(+/-12) yrs; body mass index (BMI): 29(+/-6) kg x m(-2); apnoea/hypopnoea index (AHI): 27(+/-20) events x h(-1)) were identified and used for analysis. An abnormal change in the pattern of any of the respiratory or neurological variables occurring during the observation period was defined as an episode. Each episode was registered and scored with concomitant scoring of the remaining variables. According to the episode definition three different profiles were established: 1) periods of reduction of ventilation in either variable without an arousal or cyclical desaturation, named nonpathological episode (NPE); 2) an idiopathic or nonrespiratory arousal (IA); and 3) a true respiratory event (TRE) defined as reduction or absence of flow demonstrated by either thermistor, thoraco-abdominal bands or NP accompanied by cyclical desaturation and/or arousal. For each TRE, its detection by thermistor, thoraco-abdominal bands or NP was established. A total of 877 sleep episodes were observed (42 NPE, 30 IA and 805 TRE). When compared to single or combined thermistor and bands approach, NP had the highest respiratory events detection rate, 779 (96.8%) versus 673 events (83.6%), respectively. Detection of respiratory-related arousals was also improved by NP and only 3% could account for mouth breathing respiration. It is concluded that nasal prongs improve the detection of respiratory events in patients with sleep respiratory disorders.
Impact of nasal continuous positive airway pressure treatment on quality of life in patients with obstructive sleep apnoea
Authors: Bolitschek J , Schmeiser-Rieder A , Schobersberger R , Rosenberger A , Kunze M , Aigner K
Published: November 2002

Quality-of-life (QoL) issues have become increasingly important in health care practice and research. Obstructive sleep apnoea syndrome (OSAS) results in an especially serious reduction in QoL. The purpose of this study was to measure the QoL (life satisfaction) of OSAS patients treated with nasal continuous positive airway pressure (nCPAP). We aimed to determine whether and to what extent the QoL of OSAS patients using nCPAP differs from that of randomly selected subjects without this disorder. The QoL of 67 patients treated for at least 3 months with nCPAP, 21 OSAS patients at the time of OSAS diagnosis, and 113 randomly selected persons visiting the hospital (controls) was investigated with the help of the Munich life-quality dimension list (MLDL), an instrument for cognitive assessment of elementary components (physical condition, psyche, social life, everyday life) of QoL. It was found that QoL of OSAS patients treated with nCPAP did not significantly differ from that of control subjects with regard to elementary components. The 21 untreated OSAS patients showed significantly lower scores in all four subcategories: physical condition (p<0.0005), psyche (p<0.01), social life (p<0.0005) and everyday life (p<0.007). Thus, it may be concluded that nasal continuous positive airway pressure therapy has an important impact on the quality of life of obstructive sleep apnoea syndrome patients, and signifies a further advantage in addition to clinical aspects. Treated patients are as satisfied or dissatisfied with their life as persons without this illness.
Superimposing positive end-expiratory pressure during partial liquid ventilation in experimental lung injury
Authors: Kaisers U , Kuhlen R , Keske U , Sommerer A , Mohnhaupt A , Falke KJ , Rossaint R
Published: November 2002

This study was undertaken to determine the effects of superimposing incremental levels of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) on gas exchange, respiratory mechanics and morphological changes in experimental acute lung injury (ALI). In a prospective trial, six pigs weighing 30+/-5 kg (mean+/-SD) were tracheotomized, submitted to pressure-controlled mechanical ventilation (pc-CMV) and depleted of surfactant by lung lavage. Animals were then mechanically ventilated with three levels of PEEP: 0.5, 1.0 and 1.5 kPa. PLV was then initiated by intratracheal instillation of 30 mL x kg(-1) perfluorocarbon, followed by pc-CMV with PEEP 0.5, 1.0 and 1.5 kPa. Computed tomography (CT)-based analyses of lung volumes and density were obtained after lung lavage, in PLV and during the combined application of PLV and PEEP. Simultaneously, haemodynamics, gas exchange, dynamic compliance (Cdyn) and dynamic resistance (Rdyn) were determined. Statistical analysis was performed using multivariate analyses of variance for repeated measures (p<0.05). In ALI and before PLV, the application of PEEP significantly reduced cardiac output and intrapulmonary shunt. Arterial oxygen tension (Pa,O2) was increased from 6.9 kPa (52 (42, 54) mmHg) (median, (25th and 75th percentile)) to 8.6 kPa (65 (52, 133) mmHg) (PEEP 1.0 kPa) and 15.6 kPa (117 (90, 195) mmHg) (PEEP 15 kPa) (p<0.05). The lung volume obtained by CT increased, CT density was reduced (p<0.05), Cdyn tended to increase and Rdyn to decrease (nonsignificant). PLV increased arterial carbon dioxide tension and reduced pH (p<0.05). CT lung volume and lung density were increased (p<0.05). Superimposing PEEP on PLV increased Pa,O2 from 9.3 kPa (70 (52,124) mmHg) (PEEP 0.5 kPa) to 12.9 kPa (97 (55, 233) mmHg) (PEEP 1.0 kPa) and 403 kPa (303 (64, 426) mmHg) (PEEP 1.5 kPa) (p<0.05), but had no significant effect on CT lung volume and density. It was concluded that in experimental lung injury, positive end-expiratory pressure provided alveolar recruitment. The combined application of positive end-expiratory pressure and partial liquid ventilation significantly augmented oxygenation and might eventually allow either a reduction in the volumes of perfluorocarbons required, or a reduction in positive end-expiratory pressure necessary to maintain pulmonary gas exchange in acute lung injury.
Bronchodilator response to salbutamol after chronic dosing with salmeterol or placebo
Authors: Langley SJ , Masterson CM , Batty EP , Woodcock A
Published: November 2002

It has been hypothesized that regular inhaled beta2-agonist therapy causes desensitization of beta2-receptors. The aim of this study was to define whether beta2-receptor desensitization occurs after treatment with the long-acting beta2-agonist salmeterol, assessed by measuring the bronchodilator response to cumulative repeated doses of inhaled salbutamol before and after treatment. Forty nine stable adult patients with asthma were randomized to receive either salmeterol 50 microg b.d. or placebo b.d. from an Accuhaler for 4 weeks after an initial 2 week run-in period without beta2-agonists. All patients were receiving inhaled corticosteroids. Bronchodilator responsiveness to cumulative repeated doses of inhaled salbutamol were measured before and 12 and 36 h after the last dose of study treatment. The primary efficacy endpoint was the peak forced expiratory volume in one second (FEV1) response before and after treatment. There were no significant differences between the two treatment groups in the absolute peak FEV1 or maximal peak expiratory flow (PEF) results 12 or 36 h after the last dose of study treatment. Significantly higher clinic lung function and diary card parameters were noted in the salmeterol group when compared to the placebo-treated patients, demonstrating the beneficial effects of regular salmeterol. Regular salmeterol usage did not lead to reduced efficacy of usual or higher than usual doses of salbutamol.