bluuebunny/crossref_metadata_2025 huggingface dataset:
Roles ofVibrio fischeriand Nonsymbiotic Bacteria in the Dynamics of Mucus Secretion during Symbiont Colonization of theEuprymna scolopesLight Organ
Authors: Nyholm Spencer V. , Deplancke Bart , Gaskins H. Rex , Apicella Michael A. , McFall-Ngai Margaret J.
Published: September 2002

During light organ colonization of the squidEuprymna scolopesbyVibrio fischeri,host-derived mucus provides a surface upon which environmentalV. fischeriforms a biofilm and aggregates prior to colonization. In this study we defined the temporal and spatial characteristics of this process. Although permanent colonization is specific to certain strains ofV. fischeri, confocal microscopy analyses revealed that light organ crypt spaces took up nonspecific bacteria and particles that were less than 2 μm in diameter during the first hour after hatching. However, within 2 h after inoculation, these cells or particles were not detectable, and further entry by nonspecific bacteria or particles appeared to be blocked. Exposure to environmental gram-negative or -positive bacteria or bacterial peptidoglycan caused the cells of the organ's superficial ciliated epithelium to release dense mucin stores at 1 to 2 h after hatching that were used to form the substrate upon whichV. fischeriformed a biofilm and aggregated. Whereas the uncolonized organ surface continued to shed mucus, within 48 h of symbiont colonization mucus shedding ceased and the formation of bacterial aggregations was no longer observed. Eliminating the symbiont from the crypts with antibiotics restored the ability of the ciliated fields to secrete mucus and aggregate bacteria. While colonization byV. fischeriinhibited mucus secretion by the surface epithelium, secretion of host-derived mucus was induced in the crypt spaces. Together, these data indicate that although initiation of mucus secretion from the superficial epithelium is nonspecific, the inhibition of mucus secretion in these cells and the concomitant induction of secretion in the crypt cells are specific to natural colonization byV. fischeri.
Microbial Composition of Near-Boiling Silica-Depositing Thermal Springs throughout Yellowstone National Park
Authors: Blank Carrine E. , Cady Sherry L. , Pace Norman R.
Published: September 2002

The extent of hyperthermophilic microbial diversity associated with siliceous sinter (geyserite) was characterized in seven near-boiling silica-depositing springs throughout Yellowstone National Park using environmental PCR amplification of small-subunit rRNA genes (SSU rDNA), large-subunit rDNA, and the internal transcribed spacer (ITS). We found that
Thermocrinis ruber
, a member of the order
Aquificales
, is ubiquitous, an indication that primary production in these springs is driven by hydrogen oxidation. Several other lineages with no known close relatives were identified that branch among the hyperthermophilic bacteria. Although they all branch deep in the bacterial tree, the precise phylogenetic placement of many of these lineages is unresolved at this time. While some springs contained a fair amount of phylogenetic diversity, others did not. Within the same spring, communities in the subaqueous environment were not appreciably different than those in the splash zone at the edge of the pool, although a greater number of phylotypes was found along the pool's edge. Also, microbial community composition appeared to have little correlation with the type of sinter morphology. The number of cell morphotypes identified by fluorescence in situ hybridization and scanning electron microscopy was greater than the number of phylotypes in SSU clone libraries. Despite little variation in
Thermocrinis ruber
SSU sequences, abundant variation was found in the hypervariable ITS region. The distribution of ITS sequence types appeared to be correlated with distinct morphotypes of
Thermocrinis ruber
in different pools. Therefore, species- or subspecies-level divergences are present but not detectable in highly conserved SSU sequences.
Direct and Efficient Production of Ethanol from Cellulosic Material with a Yeast Strain Displaying Cellulolytic Enzymes
Authors: Fujita Yasuya , Takahashi Shouji , Ueda Mitsuyoshi , Tanaka Atsuo , Okada Hirofumi , Morikawa Yasushi , Kawaguchi Takashi , Arai Motoo , Fukuda Hideki , Kondo Akihiko
Published: September 2002

For direct and efficient ethanol production from cellulosic materials, we constructed a novel cellulose-degrading yeast strain by genetically codisplaying two cellulolytic enzymes on the cell surface of
Saccharomyces cerevisiae
. By using a cell surface engineering system based on α-agglutinin, endoglucanase II (EGII) from the filamentous fungus
Trichoderma reesei
QM9414 was displayed on the cell surface as a fusion protein containing an RGSHis6 (Arg-Gly-Ser-His
6
) peptide tag in the N-terminal region. EGII activity was detected in the cell pellet fraction but not in the culture supernatant. Localization of the RGSHis6-EGII-α-agglutinin fusion protein on the cell surface was confirmed by immunofluorescence microscopy. The yeast strain displaying EGII showed significantly elevated hydrolytic activity toward barley β-glucan, a linear polysaccharide composed of an average of 1,200 glucose residues. In a further step, EGII and β-glucosidase 1 from
Aspergillus aculeatus
No. F-50 were codisplayed on the cell surface. The resulting yeast cells could grow in synthetic medium containing β-glucan as the sole carbon source and could directly ferment 45 g of β-glucan per liter to produce 16.5 g of ethanol per liter within about 50 h. The yield in terms of grams of ethanol produced per gram of carbohydrate utilized was 0.48 g/g, which corresponds to 93.3% of the theoretical yield. This result indicates that efficient simultaneous saccharification and fermentation of cellulose to ethanol are carried out by a recombinant yeast cells displaying cellulolytic enzymes.
Succession of Bacterial Community Structure along the Changjiang River Determined by Denaturing Gradient Gel Electrophoresis and Clone Library Analysis
Authors: Sekiguchi Hiroyuki , Watanabe Masataka , Nakahara Tadaatsu , Xu Baohua , Uchiyama Hiroo
Published: September 2002

Bacterial community structure along the Changjiang River (which is more than 2,500 km long) was studied by using denaturing gradient gel electrophoresis (DGGE) and clone library analysis of PCR-amplified 16S ribosomal DNA (rDNA) with universal bacterial primer sets. DGGE profiles and principal-component analysis (PCA) demonstrated that the bacterial community gradually changed from upstream to downstream in both 1998 and 1999. Bacterial diversity, as determined by the Shannon index (
H
′), gradually decreased from upstream to downstream. The PCA plots revealed that the differences in the bacterial communities among riverine stations were not appreciable compared with the differences in two adjacent lakes, Lake Dongting and Lake Poyang. The relative stability of the bacterial communities at the riverine stations was probably due to the buffering action of the large amount of water flowing down the river. Clone library analysis of 16S rDNA revealed that the dominant bacterial groups changed from β-proteobacteria and the
Cytophaga-Flexibacter-Bacteroides
group upstream to high-G+C-content gram-positive bacteria downstream and also that the bacterial community structure differed among the stations in the river and the lakes. The results obtained in this study should provide a reference for future changes caused by construction of the Three Gorges Dam.
Double-Staining Method for Differentiation of Morphological Changes and Membrane Integrity of
Campylobacter coli
Cells
Authors: Alonso Jose L. , Mascellaro Salvatore , Moreno Yolanda , Ferrús María A. , Hernández Javier
Published: September 2002

We developed a double-staining procedure involving NanoOrange dye (Molecular Probes, Eugene, Oreg.) and membrane integrity stains (LIVE/DEAD
Bac
Light kit; Molecular Probes) to show the morphological and membrane integrity changes of
Campylobacter coli
cells during growth. The conversion from a spiral to a coccoid morphology via intermediary forms and the membrane integrity changes of the
C. coli
cells can be detected with the double-staining procedure. Our data indicate that young or actively growing cells are mainly spiral shaped (green-stained cells), but older cells undergo a degenerative change to coccoid forms (red-stained cells). Club-shaped transition cell forms were observed with NanoOrange stain. Chlorinated drinking water affected the viability but not the morphology of
C. coli
cells.
In Vitro Adhesion Specificity of Indigenous Lactobacilli within the Avian Intestinal Tract
Authors: Edelman Sanna , Westerlund-Wikström Benita , Leskelä Susanna , Kettunen Hannele , Rautonen Nina , Apajalahti Juha , Korhonen Timo K.
Published: September 2002

In vitro adherence of
Lactobacillus
strains to cell and tissue types along the chicken alimentary tract and to ileal mucus were determined. Fresh isolates from chickens adhered to the epithelium of crop and, in a strain-dependent manner, to follicle-associated epithelium and the apical surfaces of mature enterocytes of intestinal villi. No adherence to the apical surfaces of undifferentiated enterocytes, the mucus-producing goblet cells, or the ileal mucus was detected.
Detection of
Helicobacter
Colonization of the Murine Lower Bowel by Genus-Specific PCR-Denaturing Gradient Gel Electrophoresis
Authors: Grehan Martin , Tamotia Gauri , Robertson Bronwyn , Mitchell Hazel
Published: September 2002

Helicobacter
genus-specific PCR and denaturing gradient gel electrophoresis can detect and speciate the helicobacters that colonize the lower bowel of laboratory mice. The method's sensitivity is comparable to that of species-specific PCR and may detect unnamed
Helicobacter
species. This approach should prove useful for commercial and research murine facilities.
Identification of Differences in Genome Content among
phlD
-Positive
Pseudomonas fluorescens
Strains by Using PCR-Based Subtractive Hybridization
Authors: Mavrodi D. V. , Mavrodi O. V. , McSpadden-Gardener B. B. , Landa B. B. , Weller D. M. , Thomashow L. S.
Published: September 2002

Certain 2,4-diacetylphloroglucinol-producing strains of
Pseudomonas fluorescens
colonize roots and suppress soilborne diseases more effectively than others from which they are otherwise phenotypically almost indistinguishable. We recovered DNA fragments present in the superior colonizer
P. fluorescens
Q8r1-96 but not in the less rhizosphere-competent strain Q2-87. Of the open reading frames in 32 independent Q8r1-96-specific clones, 1 was similar to colicin M from
Escherichia coli
, 3 resembled known regulatory proteins, and 28 had no significant match with sequences of known function. Seven clones hybridized preferentially to DNA from strains with superior rhizosphere competence, and sequences in two others were highly expressed in vitro and in the rhizosphere.
Simultaneous Detection of
Aeromonas salmonicida
,
Flavobacterium psychrophilum
, and
Yersinia ruckeri
, Three Major Fish Pathogens, by Multiplex PCR
Authors: del Cerro A. , Marquez I. , Guijarro J. A.
Published: September 2002

A multiplex PCR assay based on the 16S rRNA genes was developed for the simultaneous detection of three major fish pathogens,
Aeromonas salmonicida
,
Flavobacterium psychrophilum
, and
Yersinia ruckeri
. The assay proved to be specific and as sensitive as each single PCR assay, with detection limits in the range of 6, 0.6, and 27 CFU for
A. salmonicida
,
F. psychrophilum
, and
Y. ruckeri
, respectively. The assay was useful for the detection of the bacteria in artificially infected fish as well as in fish farm outbreaks. Results revealed that this multiplex PCR system permits a specific, sensitive, reproducible, and rapid method for the routine laboratory diagnosis of infections produced by these three bacteria.
Free-Living Heterotrophic Nitrogen-Fixing Bacteria Isolated from Fuel-Contaminated Antarctic Soils
Authors: Eckford Ruth , Cook Fred D. , Saul David , Aislabie Jackie , Foght Julia
Published: September 2002

Five bacterial isolates enriched from fuel-contaminated Antarctic soils fixed nitrogen in the dark heterotrophically and nonsymbiotically. Two isolates utilized jet fuel vapors and volatile hydrocarbons for growth but not in N-deficient medium. Bacteria such as these may contribute to in situ biodegradation of hydrocarbons in Antarctic soils.
Acetate Utilization and Butyryl Coenzyme A (CoA):Acetate-CoA Transferase in Butyrate-Producing Bacteria from the Human Large Intestine
Authors: Duncan Sylvia H. , Barcenilla Adela , Stewart Colin S. , Pryde Susan E. , Flint Harry J.
Published: September 2002

Seven strains ofRoseburiasp.,Faecalibacterium prausnitzii, andCoprococcussp. from the human gut that produce high levels of butyric acid in vitro were studied with respect to key butyrate pathway enzymes and fermentation patterns. Strains ofRoseburiasp. andF. prausnitziipossessed butyryl coenzyme A (CoA):acetate-CoA transferase and acetate kinase activities, but butyrate kinase activity was not detectable either in growing or in stationary-phase cultures. Although unable to use acetate as a sole source of energy, these strains showed net utilization of acetate during growth on glucose. In contrast,Coprococcussp. strain L2-50 is a net producer of acetate and possessed detectable butyrate kinase, acetate kinase, and butyryl-CoA:acetate-CoA transferase activities. These results demonstrate that different functionally distinct groups of butyrate-producing bacteria are present in the human large intestine.
Sham surgery controls: intracerebral grafting of fetal tissue for Parkinson’s disease and proposed criteria for use of sham surgery controls
Authors: Albin R L
Published: September 2002

Sham surgery is a controversial and rarely used component of randomised clinical trials evaluating surgical interventions. The recent use of sham surgery in trials evaluating efficacy of intracerebral fetal tissue grafts in Parkinson’s disease has highlighted the ethical concerns associated with sham surgery controls. Macklin, and Dekkers and Boer argue vigorously against use of sham surgery controls. Macklin presents a broad argument against sham surgery controls while Dekkers and Boer present a narrower argument that sham surgery is unnecessary in the specific setting of fetal tissue engraftment for Parkinson’s disease. I defend sham surgery controls against both these criticisms. Appropriate clinical trial design, sometimes including sham surgery, is needed to ensure that false positive trial results do not occur and endanger public safety. Results of a completed trial of fetal tissue grafting for Parkinson’s disease are used to illustrate the potential benefits of, and problems associated with, sham surgery controls. Sham surgery controls, however, should be employed only when absolutely necessary. I suggest criteria for appropriate use of sham surgery controls.
The medical career of Robert Seymour Bridges, FRCP (1844–1930): physician and Poet Laureate
Authors: Cook G C
Published: September 2002

Robert Bridges OM is the only medical graduate (he was elected to the Fellowship of the Royal College of Physicians of London in 1900) to have held the office of Poet Laureate. Educated at Corpus Christi College, Oxford and St Bartholomew’s Hospital he practised as a casualty physician at his teaching hospital (where he made a series of highly critical remarks of the Victorian medical establishment) and subsequently as a full physician to the Great (later Royal) Northern Hospital. He was also a physician to the Hospital for Sick Children. It had for long been his intention to retire from the medical profession at the early age of 40! In 1913, Bridges was appointed Poet Laureate by King George V, and following a disappointingly sparse output of “official” work, published his greatest literary contribution—The Testament of Beauty—on his 85th birthday.
Spinal reconstruction for symptomatic thoracic haemangioma using a titanium cage
Authors: Ogura T , Mori M , Hayashida T , Osawa T , Hase H
Published: September 2002

Most vertebral haemangiomas are asymptomatic. A case of spinal reconstruction for symptomatic extraosseous thoracic haemangioma using a titanium cage is reported. Radiographs of the T11 vertebra demonstrated characteristic vertical striations. Magnetic resonance imaging and computed tomography showed spinal cord compression by extraosseous tumour extension. Several tumour feeding vessels were shown by angiography. Through a transpedicular biopsy, a histological diagnosis of cavernous haemangioma was made. Embolisation of feeding vessels was performed using coils before surgery. Laminectomy and subtotal vertebrectomy were performed by a single posterior approach. Rigid stabilisation of the spine was achieved with pedicle screw systems and a cage filled with an autogenous bone graft. Five months postoperatively, stabilisation of the spine was established without loosening of the cage or pedicle screws. Clinical symptoms were improved.
On spin irreps of (1 Ii 3) 12-fold uniform NMR spin systems as invariant-based dual tensorial sets: Roles in spin physics for weight sets and their -partitional frequency catalogues
Authors: Temme F P
Published: September 2002

A direct systematic approach is given to the derivation of outer M-labelled {|IM(.)>} dual (spin) irrep sets for identical n [Formula: see text] 12-fold higher Ii nuclear spin ensembles, stressing (i) the essential role of multipartite partitions in spin physics, (ii) the value of algorithmic tableaux-based decompositions in the subsequent [Formula: see text]n combinatorical modelling, and (iii) how the dual group invariants (based on time-reversal invariance) govern the auxiliary labels of specialized dual tensors. Such (uniform inner rank) dual group basis sets (spin representations) underlie both NMR and isotopomer CNP spectral weightings. Specific applications are discussed here to illustrate the value of number partitional-based designs for statistical frequencies and recent algorithmic "sst" ([Formula: see text]n)-encoding techniques in quantized spin physics of uniform higher spin sets. In addition, a democratic recoupled form of purely SU(2) × [Formula: see text]2n projective modelling for the dual group invariants (SI) is given via an augmented democratic form of Weyl time-reversal invariance (TRV), over some regular solid geometry. From simple lattice-point geometric constraints, a maximal (2n)-index limit is established for global NMR ensemble spin symmetry.

PACS Nos.: 02.10De, 02.20-a, 05.36Ch, 11.30Er, 33.25+k, 33.20Vq
Asymptotic behavior of the eigenenergies of anharmonic oscillators V(x) = x2N + bx2
Authors: Nanayakkara A , Bandara V
Published: September 2002

Analytic semiclassical energy expansions of the anharmonic oscillator V(x) = x2N + bx2 are obtained for arbitrary N. These expressions contain the parameters b and N of the potential explicitly. Analytic expressions for energy level spacing are obtained and used to study the behavior of the eigenenergy level spacing for large energies. These expressions show that asymptotic energy level spacing of the potential V(x) = x2N + bx2 increases with the coupling strength b for N = 2 and 3, whereas it decreases for N > 3. Validity of the asymptotic expansions for noninteger N is discussed.

PACS Nos.: 03.65Ge, 03.65Sq, 02.30Mv
A simple explanation of the nonappearance of physical gluons and quarks
Authors: Hansson J
Published: September 2002

We show that the nonappearance of gluons and quarks as physical particles is a rigorous and automatic result of the full, i.e., nonperturbative, nonabelian nature of the color interaction in quantum chromodynamics (QCD). This makes it, in general, impossible to describe the color field as a collection of elementary quanta (gluons). Neither can a quark be an elementary quantum of the quark field, as the color field of which it is the source is itself a source, making isolated noninteracting quarks, crucial for a physical particle interpretation, impossible. In geometrical language, the impossibility of quarks and gluons as physical elementary particles arises due to the fact that the color YangMills space does not have a constant trivial curvature. In QCD, the particles "gluons" and "quarks" are merely artifacts of an approximation method (the perturbative expansion) and are simply absent in the exact theory. This also coincides with the empirical, experimental evidence.

PACS Nos.: 12.38Aw, 03.70+k, 11.15-q
Travelling-wave-type and stationary soliton solutions of the BransDicke equation
Authors: Dehghani M H , Shojania M
Published: September 2002

Introducing the Lax pair, it is shown that the BransDicke equation is integrable for space-times with two commuting Killing vectors. Using the inverse-scattering method given by Belinskii and Zakharov, the n soliton solutions for the case of the time-dependent metric are introduced. Specially, the one and two travelling-wave-type solitonic solutions are obtained. Also it is shown that the method could be applied to the case of stationary axially symmetric space-times with two commuting Killing vectors.

PACS Nos.: 04.20jb, 04.50+h
Time-domain study of transient fields for a thin circular loop antenna
Authors: Bishay S T , Sami G M
Published: September 2002

The transient fields in the time-domain of a thin circular loop antenna on a two-layer conducting earth model are expressed in analytical form. In these expressions, the displacement currents both in the two-layer ground and in the air region are taken into consideration. The closed-form expressions of the time-domain are obtained as the inverse Laplace transform of the derived full-wave time-harmonic solution. These time-domain solutions are obtained as a summation of wave-guide modes plus contributions from branch cuts in the complex plane of the longitudinal wave number. Numerical examples are given to indicate the important features in the wave forms of the surface fields due to step and pulsed current excitation. These features provide the means of detecting the earth's stratification, measuring the overburden height, and determining the ratio of the conductivities of the layers.

PACS Nos.: 41.20Jb, 42.25Bs, 42.25Gy, 44.05+e
Electromagnetic scattering by a dielectric sphere partially buriedin an infinte plane
Authors: Hamid A -K , Hamid M
Published: September 2002

An analytical solution of the scattering problem of a plane electromagnetic wave scattered by a dielectric spherical scatterer residing or partially buried in an infinite perfectly conducting ground plane is formulated in conjunction with the method of images. With imaging, the geometry is replaced by two touching or overlapping dielectric spheres in the absence of the ground plane, but with the given incident plane wave and its plane-wave image to satisfy the boundary conditions on the ground plane in the original problem. Numerical results are presented for the normalized scattering cross section at an arbitrary height from the ground plane, at any specific angle of incidence, and different relative dielectric constants.

PACS Nos.: 41.10H, 41.90
Unsteady hydromagnetic flow of a viscoelastic fluid with temperature-dependent viscosity
Authors: Aboul-Hassan A L , Attia H A
Published: September 2002

The flow of a conducting, viscoelastic fluid between two horizontal porous plates in the presence of a transverse-magnetic field is studied. The plates are assumed to be nonconducting and maintained at two fixed but different temperatures. The fluid viscosity is assumed to be temperature dependent and the fluid is subjected to a uniform suction from above and injection from below. The motion of the fluid is produced by a uniform horizontal pressure gradient. The equation of motion and the energy equation are solved numerically to yield the velocity and temperature distributions.

PACS Nos.: 44.05+e, 44.10+i, 44.15+a, 44.20+b, 4435+c, 47.11+j, 47.15-x, 47.15cb, 47.60+i, 47.65+a
Remarks on infrared dynamics in QED3
Authors: Boldo J L , Pimentel B M , Tomazelli J L
Published: September 2002

In this work we study how the infrared sector of the interaction Hamiltonian can affect the construction of the S-matrix operator of QED in (2+1) dimensions.

PACS Nos.: 11.55-m, 11.10Jj, 11.10Kk
Equilibration in an interacting field theory
Authors: Carrington M E , Kobes R , Kunstatter G , Pickering D , Vaz E
Published: September 2002

We use a combination of perturbation theory and numerical techniques to study the equilibration of two interacting fields that are initially at thermal equilibrium at different temperatures. Using standard rules of quantum field theory, we examine the master equations that describe the time evolution of the distribution functions for the two coupled systems. By making a few reasonable assumptions we reduce the resulting coupled integral/differential equations to a pair of differential equations that can be solved numerically relatively easily and which give physically sensible results.

PACS No.: 11.10W
The basis problem in many-worlds theories
Authors: Stapp H P
Published: September 2002

It is emphasized that a many-worlds interpretation of quantum theory exists only to the extent that the associated basis problem is solved. The core basis problem is that the robust enduring states specified by environmental decoherence effects are essentially Gaussian wave packets that form continua of non-orthogonal states. Hence they are not a discrete set of orthogonal basis states to which finite probabilities can be assigned by the usual rules. The natural way to get an orthogonal basis without going outside the Schrödinger dynamics is to use the eigenstates of the reduced density matrix, and this idea is the basis of some recent attempts by many-worlds proponents to solve the basis problem. But these eigenstates do not enjoy the locality and quasi-classicality properties of the states defined by environmental decoherence effects, and hence are not satisfactory preferred basis states. This core problem is obscured by approaches that treat the universe as a quantum computer, but it needs to be addressed and resolved before a many-worlds-type interpretation can be said to exist.

PACS No.: 03.65Bz
A supersymmetric model in three dimensions with two scalar fields
Authors: Gagné-Portelance M -P , McKeon D.G.C.
Published: September 2002

We examine a supersymmetric model in three dimensions containing two massless scalar superfields Φ1 and Φ2. The most generalized renormalizable interaction is characterized by two coupling if there is a discrete symmetry Φ1 [Formula: see text] ± Φ2; the renormalization group functions are computed to lowest order for these couplings. It is found that asymptotic freedom for one of these couplings occurs in a region of coupling-constant space.

PACS Nos.: 11.30Pb
The SchrödingerRiccati equation. The ground-state energy of Be I
Authors: Fraga S , de la Vega JM García , Fraga E S
Published: September 2002

The SchrödingerRiccati equation has been used for the prediction of the ground-state energy of Be I. A statistical calculation yields a value of 14.670 hartree, with a maximum relative error of 0.02% (in absolute value) with respect to the exact energy of 14.667 36 hartree.

PACS Nos.: 31.25Eb, 31.10+z, 02.70-c, 31.15Bs
Quantification of sand production induced improvement in productivity index
Authors: Vaziri Hans H , Lemoine Elise M , Xiao Y
Published: September 2002

Centrifuge physical model tests were performed to study the mode of failure during sand production and its concomitant impact on the productivity index. The tests simulated seepage-induced failure around a multiperforated vertical well. Results indicate that in the presence of a competent cap rock (1) sand production results in the formation of a truncated cone-shaped enlarged cavity; (2) surface subsidence of the reservoir due to loss of sand mass may result in the opening of flow channels under the cap rock; (3) for a given applied head difference, sand production ceases once the enlarged cavity reduces the pressure gradient to subcritical levels; (4) the flow becomes diverted towards the upper perforations where the cavity radius is largest; and (5) the flow rate increase varies between 5 and 10 times depending on whether the mode and volume of sanding is sufficient to result in the formation of flow channels. The study performed shows that (1) the location of perforations affects the mode and magnitude of sand production; and (2) long-term productivity can be improved through managed sand production. The presence of a competent cap rock is the key to achieving substantial increases (an order of magnitude) in productivity via sanding.Key words: centrifuge test, sand production, well-bore completion, subsidence, oil sand, flow improvement.
Stability analysis of two-dimensional excavated slopes considering strength anisotropy
Authors: Hwang Jeaan , Dewoolkar Mandar , Ko Hon-Yim
Published: September 2002

Using the finite element method, a cohesive horizontal ground is sequentially excavated until the stress state along a potential slip surface of the excavated slope reaches the critical state. Mobilized friction angle and stress ratio contours in the slope generated by the finite element solution are examined to quantify the part of the slip surface that undergoes extension resulting in anisotropic conditions. The effects of factors such as excavation depths, drainage boundary conditions, slope angles, and initial stress conditions on slope stability are investigated. It is shown that excavated slopes display anisotropic behavior and that the consideration of strength anisotropy in slope stability analysis is essential. For the example considered, it was found that the extent of the extension zone of the slip surface increases as the slope angle decreases and that this relationship is linear.Key words: slope stability, strength anisotropy, finite element method, limiting equilibrium.
Improvement in Exercise Capacity in Asymptomatic and Mildly Symptomatic Adults After Atrial Septal Defect Percutaneous Closure
Authors: Brochu Marie-Claude , Baril Jean-François , Dore Annie , Juneau Martin , De Guise Pierre , Mercier Lise-Andrée
Published: September 2002

Background—

Controversy exists as to whether secundum atrial septal defects (ASDs) in asymptomatic or mildly symptomatic New York Heart Association (NYHA) class I or II adult patients should be closed.

Methods and Results—

Thirty-seven patients (24 females; mean age 49.4 years, range 19 to 76) with a mean pulmonary to systemic flow ratio (Qp:Qs) of 2.1 (1.2 to 3.4) had a maximal oxygen uptake (V
o
2max
) determination and echocardiographic measurement of right ventricular dimensions before and 6 months after elective percutaneous closure of ASD. At baseline, mean V
o
2max
was 23.5±6.4 mL/kg per minute and was higher in the 15 NYHA I patients than in the 22 NYHA II patients (27±6.9 versus 20.8±4.6 mL/kg per minute;
P
=0.0015). V
o
2max
increased significantly at 6 months (23.5±6.4 to 26.9±6.9 mL/kg per minute;
P
<0.0001). Improvement was as marked in NYHA I (+22%;
P
<0.0001) as in NYHA II patients (+12%;
P
<0.0001), in patients with Qp:Qs 1.2 to 2.0 (+16%;
P
<0.0001) as in those with Qp:Qs >2 (+12%;
P
<0.0001), and in patients ≥40 years of age (+14%;
P
<0.0001) as in those <40 years of age (+16%;
P
<0.0001). Compared with 15 of 37 patients before closure, 35 of 37 patients were in NYHA I at 6 months. Right ventricular dimensions decreased significantly (
P
<0.0001).

Conclusions—

Adult ASD patients significantly increase their functional capacity after percutaneous defect closure. This is observed even in patients classified as asymptomatic, in those with lesser shunts, and in older patients. These findings suggest that ASD closure in an adult population should be considered even in the absence of symptoms.
Use of Tissue Velocity Imaging in the Diagnosis of Fetal Cardiac Arrhythmias
Authors: Rein A.J.J.T. , O’Donnell C. , Geva T. , Nir A. , Perles Z. , Hashimoto I. , Li X.-K. , Sahn D.J.
Published: September 2002

Background—

Precise diagnosis of cardiac arrhythmias in the fetus is crucial for a managed therapeutic approach. However, many technical, positional, and gestational age–related limitations may render conventional methods, such as M-mode and Doppler flow methodologies, or newer techniques, such as fetal electrocardiography or magnetocardiography, difficult to apply, or these techniques may be unsuitable for the diagnosis of fetal arrhythmias.

Methods and Results—

In this prospective study, we describe a novel method based on raw scan-line tissue velocity data acquisition and analysis. The raw data are available from high-frame-rate 2D tissue velocity images and allow simultaneous sampling of right and left atrial and ventricular wall velocities to yield precise temporal analysis of atrial and ventricular events. Using this timing data, a ladder diagram-like “fetal kinetocardiogram” was developed to diagram and diagnose arrhythmias and to provide true intervals. This technique was feasible and fast, yielding diagnostic results in all 31 fetuses from 18 to 38 weeks of gestation. Analysis of various supraventricular and ventricular arrhythmias was readily obtained, including arrhythmias that conventional methods fail to diagnose.

Conclusions—

The fetal kinetocardiogram opens a new window to aid in the diagnosis and understanding of fetal arrhythmias, and it provides a tool for studying the action of antiarrhythmic drugs and their effects on electrophysiological conduction in the fetal heart.
Background Incidence of Late Malapposition After Bare-Metal Stent Implantation
Authors: Shah Vivek M. , Mintz Gary S. , Apple Sue , Weissman Neil J.
Published: September 2002

Background—

Late stent malapposition has been reported to be an abnormal finding after vascular brachytherapy and, possibly, implantation of drug-eluting stents. It can only be detected if intravascular ultrasound (IVUS) is performed at follow-up. However, the “background” frequency of late stent malapposition after bare-metal stent implantation is not known.

Methods and Results—

We studied 206 patients with native artery lesions who had tubular-slotted bare-metal stent implantation and who had IVUS performed at index and after 6±3 months of follow-up. There were 9 patients (4.4%) with late malapposition, which is separation of at least 1 stent strut from the arterial wall intima that does not overlap a side-branch, with evidence of blood flow (speckling) behind the strut, and where the immediate postimplantation IVUS revealed complete apposition of the stent to the vessel wall. The location of late malapposition was the stent edge in 8 of 9 patients. The maximum area, length, volume, and arc of late malapposition measured 3.1±2.4 mm
2
, 3.3±2.2 mm, 21±27 mm
3
, and 110±61 degrees, respectively. There was an increase in external elastic membrane (EEM) area (20.7±4.9 to 26.9±4.2 mm,
P
=0.0021) and plaque area (10.1±3.7 to 14.8±3.6 mm,
P
=0.0022); however, the increase in EEM was greater than the increase in plaque. The area of late malapposition correlated directly with the increase in EEM area (
r
=0.75,
P
=0.0205).

Conclusion—

Late malapposition occurs in 4% to 5% of slotted-tube bare-metal stents, usually at stent edges. The main cause is positive remodeling out of proportion to the increase in peri-stent intimal hyperplasia.
New Efficient Catheter-Based System for Myocardial Gene Delivery
Authors: Beeri Ronen , Guerrero J. Luis , Supple Gregory , Sullivan Suzanne , Levine Robert A. , Hajjar Roger J.
Published: September 2002

Background—

Manipulating gene expression in the failing heart has therapeutic promise, but until now efficient and homogeneous cardiac gene delivery has required an open-chest approach. This study examines the hypothesis that vector delivery promoted by echo contrast microbubbles will be maximized by injection of the vectors into the aortic root with brief balloon occlusion above the sinuses, while at the same time prolonging diastole and vasodilating with acetylcholine (ACh) to maximize coronary exposure.

Methods and Results—

After incubation with albumin-coated perfluorocarbon microbubbles, an adenovirus encoding a reporter gene was infused into the aortic root of rats. To maximize delivery, the aortic root was transiently occluded with a balloon catheter during a brief ACh-induced asystole. Ultrasound was used to image the delivery and disrupt the microbubbles. Aortic occlusion with concomitant ACh increased myocardial gene expression for virus + microbubbles by >2.5-fold, from 925±165 to 2358±376 relative units (RU;
P
<0.01). This delivery system also produced substantial expression with vector alone (1473±549 RU). All uptakes were significant compared with 433±332 RU without virus.

Conclusions—

An adenoviral delivery system combining echo contrast with a catheter-based technique to maximize coronary perfusion increases gene delivery compared with echo contrast alone. This novel method permits efficient percutaneous gene delivery in closed-chest animals.
RABBINIC MIDRASH: PUBLIC OR PRIVATE
Authors: Porton Gary
Published: September 2002

This paper argues that Rabbinic Midrash is a definable literary phenomenon that has its primary locus within the Rabbinic schoolhouses of late antiquity. It argues against the claim that much of our current Rabbinic Midrash originated in the Rabbinic sermons of late antiquity. While some rabbis may have delivered sermons in synagogues or to the "community" in different public settings, we shall see that there are few specific indications of that fact. When we find rabbis within the context of synagogues, they most often are not delivering sermons. And when rabbis "preach" to the community, it is often in cities known for their Rabbinic academies. It therefore is unclear exactly to whom these "sermons" were delivered. Medieval and early modern sources indicate that Rabbinic sermons were a part of synagogue activity on Sabbaths as well as on special occasions, such as weddings and funerals. Even during these periods, however, the exact content of these sermons is in many cases far from certain. Also, changes that occurred within the Jewish communities and in their surrounding environments help to explain why Jewish sermons appear at that time. The existence of Rabbinic sermons during the medieval period accordingly does not testify to their presence in late antiquity.
THE SOCIAL TEACHING OF RABBINIC JUDAISM IN ISRAELITE CONTEXT
Authors: Neusner Jacob
Published: September 2002

The social teaching of Rabbinic Judaism takes up the narrative of the Torah and recasts it into an account of the norms of Israel's social order. Its recapitulation of the Torah's story regulates relationships between Israelites and corporate Israel, among Israelites in their units of propagation and production, and between corporate Israel and the ever-present, always-sentient God. The details coalesce to yield a clear picture of an entire social order, its relationships and its points of stability and order. To treat any detail apart from its larger context is to miss its point. That point is, Rabbinic Judaism undertakes to realize in the everyday and here-and-now of the Jews' communal existence the imperatives set forth in the Torah for the formation of God's abode on earth.
Quality control of solar radiation and sunshine measurements – lessons learnt from processing worldwide databases
Authors: Muneer T , Fairooz F
Published: September 2002

As a result of an exponential increase in the application of solar water heating, and more recently solar PV systems, measurement of the available solar radiation resource is gaining rapid momentum. New databases are being created and many of these are being made available via Internet. Up-to-date series of these data are also being sought by architects and building services professionals for better design of buildings. However, in many instances due care is not being exercised with respect to quality control of the measured dataset. Two major activities that utilized large databases of solar radiation, sunshine and cloud-cover have recently been concluded within Europe – the European Solar Radiation Atlas and the Chartered Institution of Building Services Engineers (London) Guide on ‘Weather and Solar Data’. This article provides an account of the research undertaken towards development of robust techniques for identi” cation of erroneous data and their substitution using validated methods for generating radiation and sunshine data. Such substitutions are required to complete the time-series of data when the latter are either con” rmed as being of questionable quality or are found to be missing due to station downtimes.
Experimental investigation of sensible heat transfer in fin-and-tube cooling coils
Authors: Gomaa A G , Underwood C P , Bond T J , Penlington R
Published: September 2002

The sensible heat transfer characteristics of ‘ at-fin, corrugated-fin and turbulated-fin cooling coils is investigated using a laboratory rig. Measurements at different fin geometry, inlet air conditions and inlet chilled water temperature were conducted. The Nusselt number was found to be largely independent of both inlet air and chilled water temperatures. The turbulated-fin coil was found to have the highest value of heat transfer coefficient. In particular, at the same rate of heat transfer, the corrugated- and turbulated-fin coil types required 11% and 30% less fin surface area than ‘ at-fin, respectively.
Pressure surge in building utility services exacerbated by the presence of trapped or entrained air
Authors: Swaffield J A , Ballanco J , McDougall J A
Published: September 2002

Pressure transient propagation within building services utility systems is an inevitable consequence of any change in the system operating condition. In common with a wide range of pressure surge applications, these conditions may be analysed and modelled by solving the applicable St Venant equations numerically via the method of characteristics. This paper presents the underlying basis for such models and presents applications within building services utility systems that feature trapped or entrained air as a major modifier of either the transient propagation or the system boundary conditions. In particular, surge pressures exacerbated by the effect of trapped or entrained air are considered, including dry riser and sprinkler applications. The role of entrained air in the occurrence of physical injury following the violent fracturing of a w.c. bowl is discussed and explained in terms of a transient analysis.
A new score for postnatal clinical assessment of fetal maturity in newborn infants
Authors: Klimek R. , Klimek M. , Rzepecka‐Węglarz B.
Published: September 2002

Objectives: To investigate the clinical repeatability of Klimek's method of fetal maturity assessment in newborns. Methods: A cohort of 800 consecutive singletons was assessed immediately after birth by a pediatrician, who was unaware of the infants’ gestational age. The assessment, according to Klimek's method, consisted of six criteria to evaluate posture and skin appearance, and each variable was scored from 0 to 2 points. After dividing the material into two identical groups, the results were compared with those obtained by means of Ballard's method. Results: Statistical analysis did not show statistically significant differences between the compared averages in both groups. A significant correlation between the clinically compared methods of fetal maturity grading was found (r≥0.69, t≥19, and P<0.001). Conclusions: Klimek's method of fetal maturity assessment offers a possibility of objective evaluation of maturity immediately after birth. The clinical methods used to date do not have such advantages. Moreover, they require the evaluation of 12–34 parameters, their point range is more complex and their results are given on the scale of 10–50 points. In each of the applied divisions of observed newborns, there was found a high, statistically significant correlation between the indexes evaluating maturity by means of both comparable methods (i.e. Ballard and Klimek scores), which do not take into account weight and fetal age, but refer directly to fetal maturity. The new scale, which has been proposed, is simple and produces comparable results encompassing full maturity in the range of only 6–12 points.
Treatment of cervical carcinoma in situ in HIV positive women
Authors: Williams F.S , Roure R.M , Till M , Vogler M , Del Priore G
Published: September 2002

Objectives: To evaluate the safety and effectiveness of hysterectomy vs. cone biopsy in HIV seropositive patients with carcinoma in situ of the cervix (CIS). Methods: We performed a retrospective case–control study of all HIV seropositive patients diagnosed with carcinoma in situ of the cervix from 1989 to 1995. A control group of HIV(–) women with CIS was also ascertained matched for date of diagnosis of CIS, race and age. Results: There were 439 patients with CIS, of which 45 were HIV seropositive (10.3%). Nine were treated by hysterectomy, 30 by cone biopsy, and six remained untreated. Overall, 63% of HIV(+) patients did not receive any follow‐up Pap smear (44% of hysterectomy patients, 50% of cone biopsy patients, and 83% of untreated patients; χ2 P=0.41). According to Pap smear results, 67% (10/15) cone biopsy patients and 60% (3/5) hysterectomy patients had an abnormal Pap smear after treatment (P=0.9). Median time to recurrence was 12 months in hysterectomy patients vs. 14 months in cone biopsy patients. Deaths occurred in 22% of hysterectomy patients, 17% of cone biopsy patients, and 50% of untreated patients, none due to cervical cancer. Median time to death from presentation was 27.5 months for hysterectomy patients, 11 months for cone biopsy patients, and 7 months for untreated patients (P<0.05). There were no complications in the hysterectomy group, however, two patients were readmitted after cone biopsy for bleeding. When compared to HIV(−) women with CIS, HIV(+) patients were more likely to be treated by hysterectomy (χ2 P=0.01). Conclusion: All patients diagnosed with CIS should be counseled regarding HIV prevention and testing because of a significant seropositive rate. Compliance with gynecologic follow‐up is very poor in this patient population. Special efforts should be made to enhance compliance. Cone biopsy and hysterectomy appear to be equally safe and effective in the treatment of CIS. CIS in HIV patients is a poor prognostic indicator for death from any cause.