bluuebunny/crossref_metadata_2025 huggingface dataset:
Dietary calcium supplementation increases apoptosis in the distal murine colonic epithelium
Authors: Penman I D , Liang Q L , Bode J , Eastwood M A , Arends M J
Published: July 2002

Background—Increased dietary calcium might reduce colorectal cancer risk, possibly by reduction of colonic epithelial hyperproliferation, but not all studies have demonstrated this. Little is known about the effects of calcium on colonic apoptosis.

Aim—To quantify the effects of increasing calcium on apoptosis and cell proliferation in normal murine colonic crypt epithelium.

Methods—Twenty one day old male C57Bl/6 mice were fed either control AIN-76 diet (0.5% calcium wt/wt; n = 10) or the same supplemented with calcium carbonate (1.0% calcium; n = 10) for 12 weeks. Apoptotic cells in proximal and distal segments were counted and expressed as an apoptotic index (AI: frequency of apoptosis/100 longitudinal crypts). The bromodeoxyuridine (BrdU) labelling index was also determined. Differences were analysed by the student'sttest.

Results—In control animals, the AI was significantly higher in the caecum/proximal colon (mean, 28.6; SEM, 2.0) compared with the distal colon (mean, 19.9; SEM, 1.8; p = 0.004). In the calcium treated group, the AI in the caecum/proximal colon (mean, 30.6; SEM, 1.7) was similar to controls (p = 0.71) but the AI in the distal colon was significantly greater (mean, 32.6; SEM, 1.8; p = 0.001) than in control mice and was raised to values similar to those in the proximal colon. Calcium was also associated with reduced crypt cellularity and, in the proximal colon, a downward shift in the crypt position at which apoptosis occurred. There were no significant differences in the BrdU labelling index between groups or between proximal and distal colonic segments in each group.

Conclusions—Increased dietary calcium is associated with the induction of apoptosis in normal mouse distal colonic epithelium without affecting cell proliferation. This might contribute to its putative chemopreventive role in colorectal carcinogenesis. Whether this effect is direct or indirect requires further study.
Is consent in medicine a concept only of modern times?
Authors: Dalla-Vorgia P , Lascaratos J , Skiadas P , Garanis-Papadatos T
Published: July 2002

Although the issue of consent in medical practice has grown immensely in recent years, and it is generally believed that historical cases are unknown, our research amongst original ancient Greek and Byzantine historical sources reveals that it is a very old subject which ancient philosophers and physicians have addressed. Plato, in ancient Greece, connected consent with the quality of a free person and even before him, Hippocrates had advocated seeking the patient's cooperation in order to combat the disease. In Alexander the Great's era and later on in Byzantine times, not only was the consent of the patient necessary but physicians were asking for even more safeguards before undertaking a difficult operation.

Our study has shown that from ancient times physicians have at least on occasion been driven to seek the consent of their patient either because of respect for the patient's autonomy or from fear of the consequences of their failure.
Genetic discrimination and mental illness: a case report
Authors: Wong Josephine G , Lieh-Mak Felice
Published: July 2002

With advances in genetic technology, there are increasing concerns about the way in which genetic information may be abused, particularly in people at increased genetic risk of developing certain disorders. In a recent case in Hong Kong, the court ruled that it was unlawful for the civil service to discriminate in employment, for the sake of public safety, against people with a family history of mental illness. The plaintiffs showed no signs of any mental health problems and no genetic testing was performed. This was the first case concerning genetic discrimination in common law jurisdictions, therefore the court's judgment has implications for how genetic discrimination cases may be considered in the future. The court considered it inappropriate to apply population statistics or lifetime risks to individuals while examining fitness for work. It recommended an individualised assessment of specific risks within the job, relative to other risks posed by that workplace.
The −48 C/T polymorphism in the presenilin 1 promoter is associated with an increased risk of developing Alzheimer's disease and an increased Aβ load in brain
Authors: Lambert Jean-Charles , Mann David M A , Harris Judith M , Chartier-Harlin Marie-Christine , Cumming Alistair , Coates John , Lemmon Helen , StClair David , Iwatsubo Takeshi , Lendon Corinne
Published: July 2002

Mutations in the presenilin 1 gene (PS1) account for the majority of early onset, familial, autosomal dominant forms of Alzheimer's disease (AD), whereas its role in other late onset forms of AD remains unclear. A −48 C/T polymorphism in the PS1 promoter has been associated with an increased genetic risk in early onset complex AD and moreover has been shown to influence the expression of the PS1 gene. This raises the possibility that previous conflicting findings from association studies with homozygosity for the PS1 intron 8 polymorphism might be the result of linkage disequilibrium with the –48 CC genotype. Here we provide further evidence of increased risk of AD associated with homozygosity for the −48 CC genotype (odds ratio=1.6). We also report a phenotypic correlation with Aβ40, Aβ42(43), and total Aβ load in AD brains. The −48 CC genotype was associated with 47% greater total Aβ load (p<0.003) compared to CT + TT genotype bearers. These results suggest that the –48 C/T polymorphism in thePS1 promoter may increase the risk of AD, perhaps by altering PS1 gene expression and thereby influencing Aβ load.
Effects of direction of rotation in continuous and discontinuous 8 hour shift systems
Authors: Tucker Philip , Smith Lawrence , Macdonald Ian , Folkard Simon
Published: July 2002

OBJECTIVES

Previous research has produced conflicting evidence on the relative merits of advancing and delaying shift systems. The current study assessed the effects of the direction of shift rotation within 8 hour systems, upon a range of measures including sleep, on shift alertness, physical health, and psychological wellbeing.

METHODS

An abridged version of the standard shiftwork index which included retrospective alertness ratings was completed by four groups of industrial shiftworkers on relatively rapidly rotating 8 hour systems (n=611). Two groups worked continuous systems that were either advancing or delaying; the other two groups worked discontinuous systems that were either advancing or delaying.

RESULTS

Few effects were found of direction of rotation on chronic measures of health and wellbeing, even when the systems incorporated “quick returns” (a break of only 8 hours when changing from one shift to another). This was despite the use of measures previously shown to be sensitive to the effects of a broad range of features of shift systems. However, advancing continuous systems seemed to be associated with marginally steeper declines in alertness across the shift (F(3,1080)=2.87, p<0.05). They were also associated with shorter sleeps between morning shifts (F(1,404)=4.01, p<0.05), but longer sleeps between afternoons (F(1,424)=4.16, p<0.05).

CONCLUSIONS

The absence of negative effects of advancing shifts upon the chronic outcome measures accorded with previous evidence that advancing shifts may not be as harmful as early research indicated. However, this interpretation is tempered by the possibility that difficult shift systems self select those workers most able to cope with their deleterious effects. The presence of quick returns in advancing continuous systems seemed to impact upon some of the acute measures such as duration of sleep, although the associated effects on alertness seemed to be marginal.
Increased nitric oxide in exhaled air: an early marker of asthma in non-smoking aluminium potroom workers?
Authors: Lund M B , Øksne P I , Hamre R , Kongerud J
Published: July 2002

OBJECTIVES

To study exhaled nitric oxide (NO) as a marker of airway inflammation caused by potroom exposure, hypothesising that (a) workers exposed to potroom pollutants would have higher concentrations of NO in expired air than control subjects employed at the same plant but working outside of the potroom atmosphere, and (b) that concentrations of exhaled NO in potroom employees might be positively associated with concentrations of fluoride and exposure to dust.

METHODS

A study group comprising 186 male subjects (aged 24–63 years), employed in the potrooms of one Norwegian aluminium smelter, and 40 comparable control subjects (aged 25–60 years) recruited from the same plant, were examined by measurements of exhaled and nasal concentrations of NO, spirometry, and a questionnaire on respiratory symptoms as a part of an annual health surveillance programme. Estimates of exposure to fluorides and dust for selected job categories were obtained by means of personal samplers carried by the workers.

RESULTS

In the non-smokers, the concentrations of exhaled NO were higher in the potroom workers than in the controls (median (interquartile range) 9.3 (6.2–15.6)v5.7 (4.6–8.3) ppb, p=0.001). The two groups did not differ in spirometry and asthma-like symptoms. Non-smoking potroom workers with asthma-like symptoms had higher concentrations of exhaled NO than those with no symptoms (median (interquartile range) 21.0 (19.3–41.4)v8.5 (5.9–12.8) ppb, p=0.001), but had comparable spirometric values. In subjects who smoked, the concentrations of exhaled NO did not differ significantly between potroom workers and controls (median (interquartile range) 4.6 (3.3–8.0)v4.0 (3.4–5.1) ppb. Exhaled NO was not significantly associated with either duration of employment or routine measurements of dust and fluorides.

CONCLUSIONS

Exposure to potroom pollutants is associated with increased concentrations of exhaled NO in non-smoking subjects. Nitric oxide in exhaled air may be an early marker of airway inflammation in aluminium potroom workers.
Short term influence of mechanical factors on regional musculoskeletal pain: a study of new workers from 12 occupational groups
Authors: Nahit E S , Macfarlane G J , Pritchard C M , Cherry N M , Silman A J
Published: July 2002

OBJECTIVES

To determine the influence of short term exposure to mechanical factors on regional musculoskeletal pain.

METHODS

Full time newly employed workers were recruited from 12 occupational groups and information collected by questionnaire. Subjects indicated on a blank body manikin any low back, shoulder, wrist or forearm or both, or knee pain which had occurred during the past month and had lasted more than 1 day. Data were also collected with a previously validated questionnaire on working postures, manual handling activities, and repetitive movements of the upper limb. The relations between mechanical factors and each area of pain were calculated as odds ratios (ORs) with 95% confidence intervals (95% CIs). Adjustment was made for age and sex.

RESULTS

1081 subjects (median age 23; interquartile range 20–27) were recruited to the study (a participation rate of 91%). 261 (24%) reported low back pain, 221 (20%) shoulder pain, 93 (9%) wrist or forearm pain, and 222 (21%) knee pain. Several specific manual handling activities were found to be associated with low back, shoulder, and knee pain. Carrying weights of more than 50 lbs (23 kg) on one shoulder was the factor which was most strongly associated with low back pain (OR 2.4 (95% CI 1.5 to 3.8)), shoulder pain (OR 3.1 (95% CI 1.9 to 4.8)), and knee pain (OR 3.5 (95% CI 2.2 to 5.5)), whereas forearm pain was most strongly associated with repetitive movements of the wrists (OR 1.8 (95% CI 1.04 to 3.1)). By contrast very few postures were associated with regional pain, although bending forwards in an uncomfortable position for at least 15 minutes was associated with shoulder pain (OR 1.6 (95% CI 1.2 to 2.2)) and kneeling for at least 15 minutes was associated with knee pain (OR 1.8 (95% CI 1.2 to 2.6)). Exposure to mechanical factors was most strongly associated with pain at multiple sites rather than with pains in individual regions.

CONCLUSIONS

Even among workers with only short term exposure to mechanical factors, musculoskeletal pain is increased.
Use of routinely collected data on trihalomethane in drinking water for epidemiological purposes
Authors: Keegan T , Whitaker H , Nieuwenhuijsen M J , Toledano M B , Elliott P , Fawell J , Wilkinson M , Best N
Published: July 2002

OBJECTIVES

To explore the use of routinely collected trihalomethane (THM) measurements for epidemiological studies. Recently there has been interest in the relation between byproducts of disinfection of public drinking water and certain adverse reproductive outcomes, including stillbirth, congenital malformations, and low birth weight.

METHOD

Five years of THM readings (1992–6), collected for compliance with statutory limits, were analysed. One water company in the north west of England, divided into 288 water zones, provided 15 984 observations for statistical analysis. On average each zone was sampled 11.1 times a year. Five year, annual, monthly, and seasonal variation in THMs were examined as well as the variability within and between zones.

RESULTS

Between 1992 and 1996 the total THM (TTHM) annual zone means were less than half the statutory concentration, at approximately 46 μg/l. Differences in annual water zone means were within 7%. Over the study period, the maximum water zone mean fell from 142.2 to 88.1 μg/l. Mean annual concentrations for individual THMs (μg/l) were 36.6, 8.0, and 2.8 for chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) respectively. Bromoform data were not analysed, because a high proportion of the data were below the detection limit. The correlation between chloroform and TTHM was 0.98, between BDCM and TTHM 0.62, and between DBCM and TTHM −0.09. Between zone variation was larger than within zone variation for chloroform and BDCM, but not for DBCM. There was only little seasonal variation (<3%). Monthly variation was found although there were no consistent trends within years.

CONCLUSION

In an area where the TTHM concentrations were less than half the statutory limit (48 μg/l) chloroform formed a high proportion of TTHM. The results of the correlation analysis suggest that TTHM concentrations provided a good indication of chloroform concentrations, a reasonable indication of BDCM concentrations, but no indication of DBCM. Zone means were similar over the years, but the maximum concentrations reduced considerably, which suggests that successful improvements in treatment have been made to reduce high TTHM concentrations in the area. For chloroform and BDCM, the main THMs, the component between water zones was greater than variation within water zones and explained most of the overall exposure variation. Variation between months and seasons was low and showed no clear trends within years. The results indicate that routinely collected data can be used to obtain exposure estimates for epidemiological studies at a small area level.
The role of penile prosthetic surgery in the modern management of erectile dysfunction
Authors: Jain S , Bhojwani A , Terry T R
Published: July 2002

The management of erectile dysfunction looks set to be revolutionised with the introduction of effective oral therapies. There will remain, however, some men who do not respond to conservative measures. This article reviews the important role of penile prosthetic surgery as a treatment option in these patients.
Calciphylaxis
Authors: Mathur R V , Shortland J R , El Nahas A M
Published: July 2002

The phenomenon of calciphylaxis is rare, but potentially fatal. It has been recognised for a long time in patients with chronic renal failure with secondary hyperparathyroidism. Disturbed calcium and phosphate metabolism can result in painful necrosis of skin, subcutaneous tissue and acral gangrene. Appearance of the lesions is distinctive but the pathogenesis remains uncertain. The beneficial effects of parathyroidectomy are controversial. However, correction of hyperphosphataemia or occasionally hypercalcaemia is imperative. Fulminant sepsis as a consequence of secondary infection of necrotic and gangrenous tissue is a frequent cause of patient morbidity and mortality.
Effect of clean indoor air laws on smokers: the clean air module of theSimSmokecomputer simulation model
Authors: Levy David T , Friend Karen , Polishchuk Eugene
Published: July 2002

OBJECTIVES

To develop a simulation model to examine the effects of clean indoor air laws on prevalence rates and smoking attributable deaths.

METHODS

Based on empirical and theoretical research, the effects of clean air laws are modelled by type of law. The model considers clean air laws at the state levels between 1993 and 2000, and projects the number of smokers and smoking attributable deaths in the USA under different scenarios from 2000 onward.

RESULTS

The model predicts that comprehensive clean air laws have the potential to reduce substantially the number of smokers and smoking attributable deaths, and these effects are predicted to grow over time. The predicted impact of new worksite laws are reduced when previously implemented private and public worksite restrictions are taken into account.

CONCLUSIONS

Clean indoor air laws have the ability to reduce smoking rates substantially and save lives, but their impact is likely to depend on their comprehensiveness and prior private worksite restrictions in place.
Individual flowering schedule, fruit set, and flower and seed predation in Vaccinium hirtum Thunb. (Ericaceae)
Authors: Mahoro Suzuki
Published: July 2002

Flowering phenology is a trait that determines, in part, the reproductive success of plants. In this study, the variation in flowering schedule among individuals in four subpopulations of Vaccinium hirtum Thunb. (Ericaceae) and the effects of pollinators, flower predators, and predispersal seed predators on fruit production of individuals for 2 years were investigated. To describe variation in the flowering schedule among individuals, new methods for calculating two quantitative indices, rank order and degree of synchrony with others, are presented. The methods are suitable for quantifying between-individual differences in the synchronous schedule of a temperate spring-bloom species. The 2-year phenological census showed that there was variation in flowering schedule within local subpopulations. In all subpopulations, the flowering rank was retained for 2 years, and in two subpopulations, the relative synchrony of individuals was also retained. Correlation analysis between flowering schedule and fruit set suggested that early-flowering individuals were at a disadvantage regarding pollinator availability. However, weevil and fly larvae attacks often counteracted the disadvantage; later-flowering individuals were predated more intensively than early-flowering ones. The response of V. hirtum subpopulations to the selection pressure against early flowering may be disturbed by temporal and spatial variations in the influence of pollinators and predators.Key words: flowering schedule, phenotypic variation, pollination, predispersal seed predation, flower predation, Vaccinium.
Delayed germination of basidiospores in temperate species ofCrepidotus(Fr.) Staude
Authors: Aime M C , Miller Jr. O K
Published: July 2002

Delayed basidiospore germination (endogenous dormancy) for a number of species of Crepidotus (Agaricales: Crepidotaceae) is reported for the first time. Ninety percent of recovered single spore isolates germinated between 18 and 36 weeks after collection; average germination was 25 weeks after collection. The period in which 90% of germinations occurred was between 17 February and 19 April, with 50% of recovered isolates germinating in March. Many abiotic factors were experimentally manipulated in an effort to reduce or alter the necessary incubation period without effect. The latent period was consistent for a given collection, with the majority of recovered isolates from fall-fruiting collections germinating during early spring, regardless of whether spores were plated immediately after harvesting or stored for one to several months prior to plating. The identity of the cultures derived from delayed germination was confirmed by DNA sequencing.Key words: basidiospore, dormancy, single spore isolates, Crepidotaceae, large subunit ribosomal DNA sequence data, phylogeny.
Effects of forest plantation management on herbaceous-layer composition and diversity
Authors: Roberts Mark R
Published: July 2002

I compared the species composition and diversity of vascular plants in the herbaceous layer from a chronosequence of intensively managed spruce (Picea) plantations in three age-classes (57, 1012, 1416 years) with natural, mature stands (ca. 90 years) in southeastern New Brunswick, Canada. Total species richness (stand level) averaged 8184 species in the three plantation age-classes compared with 64 species in the natural stands; richness of forest habitat species alone was 3336 in the plantations and 37 in the natural stands. More fertile sites had significantly higher values for Hill's diversity indices (N0, N1, N2). Mean N0, N1, and N2(subplot level) did not differ among stand types for all species, but N1and N2were significantly greater in the natural stands than in one or two plantation age-classes for forest habitat species alone. The two younger age-classes of plantations differed significantly in composition from the natural stands and the plantations became slightly more similar (Sørensen's index) to the natural stands with increasing age. One forest habitat species was lost and 24 others decreased in cover in the plantations. Tracking of plantations over a longer time period will be needed to determine whether these forest habitat species eventually regain their former abundance.Key words: chronosequence, forest harvesting, herbaceous layer, plantations, species diversity, species composition.
Predicting plant species diversity in response to disturbance magnitude in grassland remnants of central Alberta
Authors: Vujnovic K , Wein R W , Dale M R.T
Published: July 2002

The Intermediate Disturbance Hypothesis states that the greatest species diversity occurs at intermediate levels of disturbance because species coexistence is maintained at a nonequilibrium state and no strong competitor can dominate completely. On the other hand, diversity of exotic species is expected to increase with the disturbance magnitude. These patterns were tested for in this study. The cover of all vascular plants, mosses, and lichens in 1 × 1 m plots across a range of disturbance levels was sampled in 11 remnant grasslands within the Aspen Parkland Ecoregion of central Alberta, western Canada. The Intermediate Disturbance Hypothesis was supported for small-scale within-patch diversity for total species richness and Simpson's diversity index. Lower species diversity was found in undisturbed and lightly grazed as well as in highly disturbed plots. Intermediate levels of disturbance had reduced dominance of Festuca hallii (Vasey) Piper and increased abundance of most other species; this gave the highest species diversity. The species richness and diversity of exotic plant species showed a significant positive relationship with the magnitude of the disturbance. Understanding relationships between disturbance and plant species diversity, especially exotic plants, can influence management decisions on what disturbance regime is conducive to maintaining natural plant communities.Key words: Intermediate Disturbance Hypothesis, diversity, exotic species, grassland.
The paleoenvironment ofTyrannosaurus rexfrom southwestern Saskatchewan, Canada
Authors: McIver Elisabeth E
Published: July 2002

The recovery of identifiable plant remains intimately associated with a skeleton of Tyrannosaurus rex in southwestern Saskatchewan, Canada, provides the basis for interpreting the latest Maastrichtian (65.565 Ma) paleoenvironment of the region. Fossil plants from the site are described, and fruits formerly known as Aesculus antiquus Dawson or Ficus ceratops Knowlton are transferred to a new taxon, Spinifructus antiquus (Dawson) comb. nov. Study of the sediments of the Frenchman Formation that host the bones and plants, in combination with analysis of the plants, indicates that the regional climate was mesothermal and without winter frost, but with seasonal drought. The T. rex is believed to have roamed a broad river valley abundantly vegetated by a largely deciduous flora. The deciduous nature of the Saskatchewan paleovegetation, interpreted as a response to low winter light levels at high latitude, contrasts strongly with the contemporaneous vegetation of a few degrees latitude further south and leads to questions about how a dinosaur fauna survived in a region where the bulk of the vegetation entered an extended period of dormancy.
Modelling short-term aging of asphalt binders using the rolling thin film oven test
Authors: Shalaby Ahmed
Published: July 2002

Simulation of short-term aging of asphalt binders is a widely used procedure in asphalt binder characterization for predicting the binder response to plant mixing and paving under controlled laboratory conditions. There are two laboratory test methods for evaluating the short-term aging of asphalt binders: (i) a method using rotating pans filled with a thin asphalt film termed thin film oven test (TFOT) and (ii) a method using rolling cylindrical asphalt containers termed rolling thin film oven test (RTFOT). In this paper, an attempt is made to develop generalized models for short-term aging effects using the RTFOT aging time as a benchmark. Six binder types representing two PG grades and three source suppliers are conditioned to varying levels of RTFOT aging and tested using the dynamic shear rheometer (DSR). Aging effects are modelled using independent temperature shift models for the shear modulus and phase angle. The paper discusses the sources of errors in producing generalized models and some potential applications of aging models. The research revealed that it is possible to develop and implement such models for unmodified binders.Key words: asphalt, aging, RTFOT, DSR, binder rheology, shear modulus, phase angle.
Lactoferrin gene expression and regulation: an overview
Authors: Teng Christina T
Published: July 2002

Lactoferrin is highly conserved among human, mouse, bovine, and porcine species. The numbers of amino acids encoded by 15 of the 17 exons in these species are identical, and in 12 locations, they have identical codon interruptions at the intron-exon splice junctions. However, lactoferrin expression is both ubiquitous and species, tissue, and cell-type specific. It is differentially regulated through multiple signaling pathways such as steroid hormone, growth factor, and kinase cascade pathways. Comparing the lactoferrin gene promoters from different species, common and different characteristics are observed. The human, mouse, bovine, porcine, and bubaline (African antelope) promoters all contain a noncanonical TATA box with an adjacent Sp1 site. Both human and mouse have multiple steroid hormone response elements, while none are found in the other species studied, suggesting that the lactoferrin gene is differentially regulated among different species by steroid hormones. Several transcription factors have been identified that are crucial for the expression of the lactoferrin gene during differentiation of the myeloid cells and in estrogen and epidermal growth factor regulation. This article provides an overview on lactoferrin expression and regulation in different species.Key words: lactoferrin, gene promoter, transcription factor, estrogen, xenoestrogen.
Low temperature interface-mineralizing route to hollow CuS, CdS, and NiS spheres
Authors: Jiang Xuchuan , Xie Yi , Lu Jun , Zhu Liying , He Wei , Liu Xianming
Published: July 2002

Submicrometer hollow CuS, CdS, and NiS spheres with diameters between 400 and 1300 nm were successfully prepared through an interface-mineralizing reaction in a NH3·H2OCS2 solution at low temperature. Several techniques were applied to characterize the interesting self-assembled structures. The compositions of the prepared CuS, CdS, and NiS materials were confirmed by X-ray powder diffraction (XRD), the surface atomic ratios and the valence state of ions were examined by X-ray photoelectron energy spectroscopy (XPS), and the morphologies of products by transmission electron microscope (TEM). The optical properties, including absorption and emission, were recorded by UVvis absorption and fluorescence spectroscopy, respectively. In this approach, ethylenediamine (en) was substituted by aqueous ammonia (NH3·H2O) to avoid violent reactions with carbon disulfide (CS2). The main advantage to this approach is that both ammonia and CS2 played multi-functional roles in the assembly of hollow-sphere structures. The reaction sources themselves (CS2) served as the reaction template and required no other templates to support it. The proposed interface-mineralizing mechanism is discussed, and the hollow-sphere structures obtained are envisioned to have applications in area of materials science.Key words: hollow-sphere structure, NH3·H2OCS2, metal sulfides
Estimation of vaginal probiotic lactobacilli growth parameters with the application of the Gompertz model
Authors: Tomás María Silvina Juárez , Labanda Elena Bru de , de Ruiz Holgado Aída Pesce , Nader-Macías María Elena
Published: July 2002

Lactobacilli are widely described as probiotic microorganisms used to restore the ecological balance of different animal or human tracts. For their use as probiotics, bacteria must show certain characteristics or properties related to the ability of adherence to mucosae or epithelia or show inhibition against pathogenic microorganisms. It is of primary interest to obtain the highest biomass and viability of the selected microorganisms. In this report, the growth of seven vaginal lactobacilli strains in four different growth media and at several inoculum percentages was compared, and the values of growth parameters (lag phase time, maximum growth rate, maximum optical density) were obtained by applying the Gompertz model to the experimental data. The application and estimation of this model is discussed, and the evaluation of the growth parameters is analyzed to compare the growth conditions of lactobacilli. Thus, these results in lab experiments provide a basis for testing different culture conditions to determine the best conditions in which to grow the probiotic lactobacilli for technological applications.Key words: Gompertz model, lactobacilli, growth parameters, vaginal probiotic.
The effect of handling and blood removal on plasma levels and hepatic deiodination of thyroid hormones in adult male and female rainbow trout, Oncorhynchus mykiss
Authors: Todd Keith J , Eales J Geoffrey
Published: July 2002

We studied the effects of handling and blood removal (0.4% of body mass) on the thyroid system of fasted ~1000-g adult male and female rainbow trout, Oncorhynchus mykiss, over a 3-day period. Relative to undisturbed controls, bleeding lowered the mean hematocrit (HCT) by 19% and on day 1 increased the hepatic inner-ring deiodination of 3,5,3'-triiodothyronine (T3) (T3IRD), but did not alter thyroxine (T4) outer-ring deiodination (T4ORD) or inner-ring deiodination (T4IRD) activity or plasma T4 or T3 levels. Regardless of treatment, hepatic T4ORD activity and HCT were lower in females than in males, and over the 3 days following bleeding, the plasma T3 level increased and the plasma T4 level decreased progressively for both sexes. We conclude that handling and bleeding induce a temporary increase in hepatic T3 conversion to 3,3'-diiodothyronine with no change in T4 conversion to reverse T3. This is consistent with independent control of T3IRD and T4IRD activities. Furthermore, HCT and hepatic T4ORD activity are lower in adult females, and 10 days after transfer of trout to smaller tanks, plasma T4 and T3 levels may still be adjusting.
REPRESENTATIONS OF REFLECTION ALGEBRAS
Authors: MOLEV A. I. , RAGOUCY E.
Published: July 2002

We study a class of algebras B(n,l) associated with integrable models with boundaries. These algebras can be identified with coideal subalgebras in the Yangian for gl(n). We construct an analog of the quantum determinant and show that its coefficients generate the center of B(n,l). We develop an analog of Drinfeld's highest weight theory for these algebras and give a complete description of their finite-dimensional irreducible representations.
Low Energy Scattering for Nonlinear Schrödinger Equations in Fractional Order Sobolev Spaces
Authors: Nakamura M. , Ozawa T.
Published: July 2002

We consider the scattering problem for the nonlinear Schrödinger equations with interactions behaving as a power p at zero. In the critical and subcritical cases (s≥n/2-2/(p-1)≥0), we prove the existence and asymptotic completeness of wave operators in the sense of Sobolev norm of order s on a set of asymptotic states with small homogeneous norm of order n/2-2/(p-1) in space dimension n≥1.
SINGULAR LOCI IN HOLOMORPHIC FAMILIES
Authors: HARRIS ADAM
Published: July 2002

Let [Formula: see text] be a proper flat morphism between manifolds, and [Formula: see text] an analytic subset, such that the fibres Xt, for all [Formula: see text], determine a locally trivial deformation of a compact complex manifold. Non-generic fibres Xt, for t ∈ A, may be taken a priori to be singular spaces, or to have a smooth complex structure which is biholomorphically distinct from their generic neighbours. The main theorem of this article provides a sufficient condition for local triviality of the entire family [Formula: see text], in terms of the dimension of A and of the singular subvarieties of certain "degeneracy loci" in [Formula: see text]. Several specific applications of the main theorem are subsequently examined, some of which correspond sharply with examples of "structure-jumping" in complex deformations and "jumping loci" of vector bundles on complex projective space.
ULTRACOMPACT STARS WITH MULTIPLE NECKS
Authors: KARLOVINI MAX , ROSQUIST KJELL , SAMUELSSON LARS
Published: July 2002

We discuss ultracompact stellar objects which have multiple necks in their optical geometry. There are in fact physically reasonable equations of state for which the number of necks can be arbitrarily large. The proofs of these statements rely on a recent regularized formulation of the field equations for static spherically symmetric models due to Nilsson and Uggla. We discuss in particular the equation of state p = ρ - ρ s which plays a central role in this context.
$Z\to \nu\bar \nu\gamma$ DECAY IN BEYOND STANDARD MODEL
Authors: AYDIN C. , BAYAR M.
Published: July 2002

The rare [Formula: see text] decay beyond Standard Model is studied. The value of the magnetic moment of neutrino is obtained. A comparison of our result on neutrino magnetic moment with the existing in literature result is present.
SUFFICIENT EXTRA DIMENSIONS
Authors: LUNDBERG WAYNE R.
Published: July 2002

Matrix algebra notation in introduced which extends Dirac abstract vector notation to explicitly describe standard hadrons, leptons and a specific type of 1-brane. The 3×3×3 matrix notation is easily used with the path integral approach to model both strong and weak interactions. The specific 1-brane, called a tripartite string (a type of orientifold), has three extra spatial dimensions and three extra curvature dimensions which are necessary to describe standard particles. The extra spatial dimensions compactify to one area-like metric which, when scaled according to the Randall-Sundrum approach, gives a mass metric which is orthogonal to fundamental particle quanta. A model of photons and the massive, oscillating neutrio is inherent to the tripartite string. R-S scaling is further employed in conjunction with complex gravity to produce a unique cosmological model which inherently explains the cosmological 'constant'. This model of the universe is cyclic in mass and time, where cosmological time is treated as an imaginary metric. It is further established that, for consistency with M/string theory, the 'singularity' of black hole is in fact finite; and that a tetrahedral structure qualitatively models the source of Galactic Annihilation Fountains.
EFFECTIVE LOW-ENERGY THEORIES AND QCD DIRAC SPECTRA
Authors: TOUBLAN D. , VERBAARSCHOT J. J. M.
Published: July 2002

We analyze the smallest Dirac eigenvalues by formulating an effective theory for the Dirac spectrum. We find that in a domain where the kinetic term of the effective theory can be ignored, the Dirac eigenvalues are distributed according to a Random Matrix Theory with the global symmetries of the QCD partition function. The kinetic term provides information on the slope of the average spectral density of the Dirac operator. In the second half of this lecture we interpret quenched QCD Dirac spectra (with eigenvalues scattered in the complex plane) in terms of an effective low energy theory.
SPATIALLY DEPENDENT AMPLIFICATION OF AN EXCITONIC BOSE-EINSTEIN CONDENSATE IN Cu2O
Authors: FORTIN EMERY , MASSE MATHIEU
Published: July 2002

Experimental results are presented on the spatial dependence of amplification of a travelling Bose-Einstein condensate of excitons in Cu 2 O . The exciton condensate is created at T = 1.8 K by high intensity pulsed laser illumination (λ = 532 nm). Amplification of the moving condensate is triggered by the local, time-delayed injection of thermal excitons created by a lateral laser pulse tuned at the 1S orthoexciton resonance (λ = 609.48 nm), perpendicular to the path of the condensate. The amplification factor depends on the trigger time of the lateral laser pulse and is related to the stimulated scattering into the condensate of non-condensed excitons present in the crystal volume. A spatial correlation is also observed between the amplification factor and the optical attenuation of the lateral laser radiation induced by the passing condensate.
CARBON BONDING STATES AND MECHANICAL PROPERTIES OF HYDROGENATED DLC FILMS DEPOSITED IN ELECTROSTATIC AND ELECTROMAGNETIC RF PLASMA MODES
Authors: SUN Z. , XU S. , OSTRIKOV K. N. , TSAKADZE E. L. , TSAKADZE Z. L.
Published: July 2002

Efficient hydrogenated diamond-like carbon (DLC) film deposition in a plasma reactor that features both the capacitive and inductively coupled operation regimes is reported. The hydrogenated DLC films have been prepared on silicon chemical vapor deposition (CVD) system. At low RF powers, the system operates as an asymmetric capacitively coupled plasma source, and the film deposition process is undertaken in the electrostatic (E) discharge regime. The films deposited in the electrostatic mode feature graphite-like structure. Above the mode transition threshold, the high-density inductively coupled plasma is produced in the electromagnetic (H) discharge regime. Raman spectrometry suggests the possibility to control relative proportions of sp2 and sp3 hybridized carbon. Variation of the DC substrate bias results in dramatic modification of the film structure from the polymeric (unbiased substrates) to the diamond-like (optimized bias). It has been shown that the deposition rate and hardness of the CH4+Ar gas mixture discharge, the DLC film exhibits mecha nical hardness of 18 GPa, Young's modulus of 170 GPa, and compressive stress of 1.3 GPa.
EFFECT OF SUBSTRATE TEMPERATURE ON GROWTH OF NITROGEN INCORPORATED CAMPHORIC CARBON FILMS BY PULSED LASER ABLATION
Authors: Rusop M. , Mominuzzaman S. M. , Soga T. , Jimbo T. , Umeno M.
Published: July 2002

gas ambient with varying substrate temperature from 20°C to 500°C. The effects of the substrate temperature and ambient nitrogen gas pressure on the surface morphology, composition, structure, and electrical properties of the nitrogen incorporated camphoric carbon thin films have been investigated by standard techniques. We found that the amorphous structure of CNx films can be changed by substrate temperature and the CNx films with high nitrogen content have relatively high electrical resistivity.
SYNTHESIS OF CRYSTALLITES OF CARBON NITRIDE IN AMORPHOUS CARBON
Authors: GOPALAKRISHNAN B. , SUBRAMANYAM S. V.
Published: July 2002

We report the successful synthesis of crystalline carbon nitride by chemical vapor deposition of certain nitrogen containing organic precursors. The precursor is heated and the vapors enter the hot deposition zone where they are pyrolysed and deposited in the form of thin films over pretreated substrates. The powder x-ray diffraction analysis shows clear peaks corresponding to the carbon nitride crystals of tetragonal form in addition to a broad hump corresponding to the amorphous nitrogenated carbon. The crystallites size is ~300Å and the volume fraction of the crystallites is about ~7%. The optimum conditions of preparation are found out. The Infrared spectra of these samples also suggest the formation of Carbon Nitride crystals. The analysis reconfirms that the material contains crystallites of Carbon Nitride embedded in an amorphous matrix of nitrogenated carbon. Further the material is characterized by C,H,N elemental analysis, EDX and Raman spectra. Since all the above analyses probe the bulk material, the background amorphous matrix in this case, expecting a clear evidence of nanometer sized crystallites from these tests are unlikely. Attempts are being made to increase the yield of these carbon nitride crystallites.
DEGENERATE GASES UNDER HARMONIC CONFINEMENT IN ONE DIMENSION: RIGOROUS RESULTS IN THE IMPENETRABLE-BOSONS/SPIN-POLARIZED-FERMIONS LIMIT
Authors: VIGNOLO P. , MINGUZZI A. , TOSI M. P.
Published: July 2002

Developments in the realization and study of ultracold atomic gases inside elongated magnetic traps and atom waveguides have stimulated calculations of equilibrium properties and excitation spectra for mesoscopic clouds of hard-core bosons and of spin-polarized fermions moving under an external harmonic potential in one dimension. A rigorous correspondence exists between the wave functions of these two types of system, allowing a number of exact results to be obtained. The main theoretical techniques and results are reviewed in this article, with emphasis on their relevance in regard to tests of the Thomas–Fermi approximation for confined Fermi fluids and to the foundations of density functional theory for inhomogeneous quantum systems.
EFFECT OF ION-ENERGY ON THE PROPERTIES OF AMORPHOUS GaN FILMS PRODUCED BY ION-ASSISTED DEPOSITION
Authors: LANKE UDAY , KOO ANNETTE , GRANVILLE SIMON , TRODAHL JOE , MARKWITZ ANDREAS , KENNEDY JOHN , BITTAR ANTOINE
Published: July 2002

Amorphous GaN films were deposited on various substrates viz. Si (100), quartz, glass, Al, stainless steel and glassy carbon by thermal evaporation of gallium in the presence of energetic nitrogen ions from a Kaufman source. The films were deposited at room temperature and 5 × 10-4 mbar nitrogen partial pressure. The effect of a low energy nitrogen ion beam during the synthesis of films was investigated for energies 40 eV and 90 eV. The N:Ga atomic ratio, bonding state, microstructure, surface morphology, and electrical properties of the deposited a-GaN films were studied by different characterisation techniques. The films are found to be X-ray amorphous in nature, which is confirmed by Raman spectroscopy. Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA) indicate the N:Ga atomic ratio in the films. The 400-750 eV energy range is thought to be optimal for the production of single-phase amorphous GaN . The effect of ion-energy on optical, Raman, and electrical conductivity measurements of the films is also presented.
WHAT IS THE SOURCE OF LIGHT IN SONOLUMINESCENCE?
Authors: BRODSKY A. M.
Published: July 2002

Physical analysis is presented showing that the intriguing effect of sonoluminescence cannot be explained in the framework of classical macroscopic hydrodynamic models. It is stressed that the understanding of sonoluminescence is impossible without invoking a "new" physics which has to include mesoscopic collective quantum effects. The conclusion drawn is that the light emission in sonoluminescence is the first example of collective optical transition experimentally observed three decades before the first laser was built.
CYCLIC SEQUENCE ALIGNMENTS: APPROXIMATE VERSUS OPTIMAL TECHNIQUES
Authors: MOLLINEDA R. A. , VIDAL E. , CASACUBERTA F.
Published: July 2002

The problem of cyclic sequence alignment is considered. Most existing optimal methods for comparing cyclic sequences are very time consuming. For applications where these alignments are intensively used, optimal methods are seldom a feasible choice. The alternative to an exact and costly solution is to use a close-to-optimal but cheaper approach. In previous works, we have presented three suboptimal techniques inspired on the quadratic-time suboptimal algorithm proposed by Bunke and Bühler. Do these approximate approaches come sufficiently close to the optimal solution, with a considerable reduction in computing time? Is it thus worthwhile investigating these approximate methods? This paper shows that approximate techniques are good alternatives to optimal methods.
CLARIFYING CHAOS III: CHAOTIC AND STOCHASTIC PROCESSES, CHAOTIC RESONANCE, AND NUMBER THEORY
Authors: BROWN RAY , CHUA LEON O.
Published: July 2002

In this tutorial we continue our program of clarifying chaos by examining the relationship between chaotic and stochastic processes. To do this, we construct chaotic analogs of stochastic processes, stochastic differential equations, and discuss estimation and prediction models. The conclusion of this section is that from the composition of simple nonlinear periodic dynamical systems arise chaotic dynamical systems, and from the time-series of chaotic solutions of finite-difference and differential equations are formed chaotic processes, the analogs of stochastic processes. Chaotic processes are formed from chaotic dynamical systems in at least two ways. One is by the superposition of a large class of chaotic time-series. The second is through the compression of the time-scale of a chaotic time-series. As stochastic processes that arise from uniform random variables are not constructable, and chaotic processes are constructable, we conclude that chaotic processes are primary and that stochastic processes are idealizations of chaotic processes.

Also, we begin to explore the relationship between the prime numbers and the possible role they may play in the formation of chaos.
ON BIFURCATIONS OF SPIRAL WAVES IN THE PLANE
Authors: NIKOLAEV E. V. , BIKTASHEV V. N. , HOLDEN A. V.
Published: July 2002

We describe the simplest bifurcations of spiral waves in reaction–diffusion systems in the plane and present the list of model systems. One-parameter bifurcations of one-armed spiral waves are fold and Hopf bifurcations. Multiarmed spiral waves may additionally undergo a period-doubling pitchfork bifurcation, when two congruent spiral wave solutions, having the "double" period, branch from the original spiral wave at the bifurcation point.
SIMPLEST NORMAL FORMS OF HOPF AND GENERALIZED HOPF BIFURCATIONS
Authors: YU P.
Published: July 2002

The normal forms of Hopf and generalized Hopf bifurcations have been extensively studied, and obtained using the method of normal form theory and many other different approaches. It is well known that if the normal forms of Hopf and generalized Hopf bifurcations are expressed in polar coordinates, then all odd order terms must, in general, remain in the normal form. In this paper, three theorems are presented to show that the conventional normal forms of Hopf and generalized Hopf bifurcations can be further simplified. The forms obtained in this paper for Hopf and generalized Hopf bifurcations are shown indeed to be the "simplest", and at most only two terms remain in the amplitude equation of the "simplest normal form" up to any order. An example is given to illustrate the applicability of the theory. A computer algebra system using Maple is used to derive all the formulas and verify the results presented in this paper.