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Purpose: The aim of this study was to investigate the current application of artificial intelligence (AI) tools in the teaching of ultrasound skills as they pertain to gynaecological ultrasound. Methods: A scoping review was performed. Eight databases (MEDLINE, EMBASE, EMCARE, CINAHL, Scopus, Web of Science, IEEE Xplore and ACM digital library) were searched in December 2022 using predefined keywords. All types of publications were eligible for inclusion so long as they reported the use of an AI tool, included reference to or discussion of teaching or the improvement of ultrasound skills and pertained to gynaecological ultrasound. Conference abstracts and non‐English language papers which could not be adequately translated into English were excluded. Results: The initial database search returned 481 articles. After screening against our inclusion and exclusion criteria, two were deemed to meet the inclusion criteria. Neither of the articles included reported original research (one systematic review and one review article). Neither of the included articles explicitly provided details of specific tools developed for the teaching of ultrasound skills for gynaecological imaging but highlighted similar applications within the field of obstetrics which could potentially be expanded. Conclusion: Artificial intelligence can potentially assist in the training of sonographers and other ultrasound operators, including in the field of gynaecological ultrasound. This scoping review revealed however that to date, no original research has been published reporting the use or development of such a tool specifically for gynaecological ultrasound. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to assess the accuracy of transvaginal ultrasound (TVUS) for the mapping of endometriosis before surgery when performed by sonographers in an outpatient women's imaging centre. Methods: A prospective longitudinal cohort study was performed. The study group comprised of 201 women who underwent a comprehensive TVUS assessment, performed by a sonographer. Laparoscopy was performed as the reference standard. Complete TVUS and surgical data were available for 53 women who were included in the final analysis. Results: Endometriosis was confirmed at a surgery in 50/53 (94.3%) participants, with 25/53 (47.2%) having deep endometriosis (DE) nodules and/or endometriomas present. TVUS for mapping of DE had an overall sensitivity of 84.0%, specificity of 89.3%, PPV of 87.5%, NPV of 86.2%, LR+ of 7.85, LR− of 0.18, and accuracy of 86.8% (P < 0.001). Ovarian immobility had poor sensitivity for detecting localised superficial endometriosis, DE, adhesions, and/or endometriomas (Left = 61.9% and right = 13.3%) but high specificities (left = 87.5% and right = 94.7%). Site‐specific tenderness had low sensitivities and moderate specificities for the same. All soft markers of endometriosis failed to reach statistical significance except for left ovarian immobility (P = <0.001). Conclusion: Sonographers well experienced in obstetric and gynaecological imaging, working in an outpatient women's imaging setting can accurately map DE; however, the performance of soft markers for detection of SE was poor. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the adequacy of immunological recovery and virological suppression in response to antiretroviral therapy (ART) in the growing population of older people living with HIV (PLWH), as treatment regimens become more effective and tolerable. Methods: An interprovincial Canadian cohort of treatment‐naïve PLWH who initiated ART after 1 January 2000 was used and age assessed in decades. Longitudinal absolute CD4 count response to treatment was modelled using generalized estimating equations. Cumulative incidence functions and proportional hazards models with a competing risk of death were used to estimate time to: (1) CD4 ≥ 200 cells/µL, (2) CD4 ≥ 500 cells/µL, (3) virological suppression (≤ 50 copies/mL), and (4) virological failure (> 200 copies/mL). Results: In all, 12 489 individuals starting ART between 2000 and 2016 with one or more post‐treatment CD4 count or viral load were included in the analysis. Age > 60 years was associated with lower absolute CD4 recovery (adjusted β = −31 cells/µL) compared with age ≤ 30 years when pre‐treatment CD4 count and other covariates were accounted for. Older age groups were less likely to achieve a CD4 ≥ 500 cells/µL, with the greatest effect in the > 60 group [adjusted hazard ratio (aHR) = 0.69, 95% confidence interval (CI): 0.57–0.84 vs. age ≤ 30). Older age groups were more likely to achieve viral suppression (age > 60, aHR = 1.20, 95% CI: 1.05–1.37) and less likely to have virological failure (age > 60, aHR = 0.46, 95% CI: 0.3–0.71) compared with those aged ≤ 30 years. Conclusions: Older adults have robust virological responses to ART; however, individuals over the age 60 are more likely to experience blunted CD4 recovery. [ABSTRACT FROM AUTHOR]

Objectives: Intravenous infusion of Intralipid is an adjunct therapy in assisted reproduction treatment (ART) when immune‐associated infertility is suspected. Here, we evaluated the effect of Intralipid infusion on regulatory T cells (Treg cells), effector T cells and plasma cytokines in peripheral blood of women undertaking IVF. Methods: This prospective, observational pilot study assessed Intralipid infusion in 14 women exhibiting recurrent implantation failure, a clinical sign of immune‐associated infertility. Peripheral blood was collected immediately prior to and 7 days after intravenous administration of Intralipid. Plasma cytokines were measured by Luminex, and T‐cell subsets were analysed by flow cytometry. Results: A small increase in conventional CD8+ T cells occurred after Intralipid infusion, but no change was seen in CD4+ Treg cells, or naïve, memory or effector memory T cells. Proliferation marker Ki67, transcription factors Tbet and RORγt, and markers of suppressive capacity CTLA4 and HLA‐DR were unchanged. Dimensionality‐reduction analysis using the tSNE algorithm confirmed no phenotype shift within Treg cells or other T cells. Intralipid infusion increased plasma CCL2, CCL3, CXCL8, GM‐CSF, G‐CSF, IL‐6, IL‐21, TNF and VEGF. Conclusion: Intralipid infusion elicited elevated pro‐inflammatory cytokines, and a minor increase in CD8+ T cells, but no change in pro‐tolerogenic Treg cells. Notwithstanding the limitation of no placebo control, the results do not support Intralipid as a candidate intervention to attenuate the Treg cell response in women undergoing ART. Future placebo‐controlled studies are needed to confirm the potential efficacy and clinical significance of Intralipid in attenuating cytokine induction and circulating CD8+ T cells. [ABSTRACT FROM AUTHOR]

Objectives We sought to compare all-cause mortality of people living with HIV and accessing care in Canada and the UK. Methods Individuals from the Canadian Observational Cohort ( CANOC) collaboration and UK Collaborative HIV Cohort ( UK CHIC) study who were aged ≥ 18 years, had initiated antiretroviral therapy ( ART) for the first time between 2000 and 2012 and who had acquired HIV through sexual transmission were included in the analysis. Cox regression was used to investigate the difference in mortality risk between the two cohort collaborations, accounting for loss to follow-up as a competing risk. Results A total of 19 960 participants were included in the analysis ( CANOC, 4137; UK CHIC, 15 823). CANOC participants were more likely to be older [median age 39 years (interquartile range ( IQR): 33, 46 years) vs. 36 years ( IQR: 31, 43 years) for UK CHIC participants], to be male (86 vs. 73%, respectively), and to report men who have sex with men ( MSM) sexual transmission risk (72 vs. 56%, respectively) (all P < 0.001). Overall, 762 deaths occurred during 98 798 person-years ( PY) of follow-up, giving a crude mortality rate of 7.7 per 1000 PY [95% confidence interval ( CI): 7.1, 8.3 per 1000 PY]. The crude mortality rates were 8.6 (95% CI: 7.4, 10.0) and 7.5 (95% CI: 6.9, 8.1) per 1000 PY among CANOC and UK CHIC study participants, respectively. No statistically significant difference in mortality risk was observed between the cohort collaborations in Cox regression accounting for loss to follow-up as a competing risk (adjusted hazard ratio 0.86; 95% CI: 0.72-1.03). Conclusions Despite differences in national HIV care provision and treatment guidelines, mortality risk did not differ between CANOC and UK CHIC study participants who acquired HIV through sexual transmission. [ABSTRACT FROM AUTHOR]

Objectives Nonoccupational post-exposure prophylaxis ( nPEP) is a strategy to reduce the risk of HIV infection in those with high-risk exposure. This study characterized nPEP awareness among gay, bisexual and other men who have sex with men ( MSM) in Metro Vancouver, British Columbia, Canada after a pilot nPEP programme established in 2012. Methods Momentum Health Study participants were MSM aged ≥16 years recruited via respondent-driven sampling ( RDS) who completed a computer-assisted self-interview. Stratifying patients by HIV status, we used multivariable logistic regression with backward selection to identify factors associated with nPEP awareness. All analyses were RDS-adjusted. Results A total of 51.9% (112 of 173) of HIV-positive and 48.5% (272 of 500) of HIV-negative participants had heard of nPEP. Only 3% (five of 106) of HIV-negative participants who reported recent high-risk sex used nPEP. Generally, nPEP awareness was higher for participants who engaged in sexual activities with increased HIV transmission potential. Factors associated with greater awareness among HIV-negative participants included recent alcohol use, higher communal sexual altruism, previous sexually transmitted infection diagnosis, and greater perceived condom use self-efficacy. Other factors associated with greater awareness among HIV-negative participants included white race/ethnicity, gay sexual identity, more formal education, lower personal sexual altruism, and Vancouver residence. Greater nPEP awareness among HIV-positive participants was associated with greater perceived agency to ask sexual partners' HIV status and more frequently reporting doing so, a higher number of lifetime receptive sex partners, and greater access to condoms. Conclusions Following implementation of an nPEP pilot programme, nPEP awareness among HIV-negative MSM was 51% and use was 3%. These data support the need to expand access to and actively promote nPEP services. [ABSTRACT FROM AUTHOR]

Objectives: Opioid use and opioid-related mortality have increased dramatically since the 1990s in North America. The effect of opioids on the liver is incompletely understood. Some studies have suggested that opioids cause liver damage and others have failed to show any harm. HIV/hepatitis C virus (HCV)-coinfected persons may be particularly vulnerable to factors increasing liver fibrosis. We aimed to describe opioid use in an HIV/HCV-coinfected population in Canada and to estimate the association between opioid use and liver fibrosis. Methods: We conducted a cross-sectional descriptive analysis of the Canadian Co-infection Cohort Study data to characterize opioid use. We then conducted a longitudinal analysis to assess the average change in aspartate aminotransferase-to-platelet ratio index (APRI) score associated with opioid use using a generalized estimating equation with linear regression. We assessed the progression to significant liver fibrosis (APRI ≥ 1.5) associated with opioid use with pooled logistic regression. Results: In the 6 months preceding cohort entry, 32% of the participants had received an opioid prescription, 28% had used opioids illicitly and 18% had both received a prescription and used opioids illicitly. Neither prescribed nor illicit opioid use was associated with a change in the median APRI score [exp(α) 0.99 (95% confidence interval (CI) 0.82, 1.12) and exp(β) 0.95 (95% CI 0.81, 1.10), respectively] or with faster progression to liver fibrosis [hazard odds ratio (HOR) 1.20 (95% CI 0.73, 1.67) and HOR 1.09 (95% CI 0.63, 1.55), respectively]. Conclusions: Although opioids were commonly used both legally and illegally in our cohort, we were unable to demonstrate a negative impact on liver fibrosis progression. [ABSTRACT FROM AUTHOR]

Objectives Hepatitis C virus ( HCV) has emerged as an important health problem in the era of effective HIV treatment. However, very few data exist on the health status and disease burden of HIV/ HCV-coinfected Canadians. Methods HIV/ HCV-coinfected patients were enrolled prospectively in a multicentre cohort from 16 centres across Canada between 2003 and 2010 and followed every 6 months. We determined rates of a first liver fibrosis or endstage liver disease ( ESLD) event and all-cause mortality since cohort enrolment and calculated standardized mortality ratios compared with the general Canadian population. Results A total of 955 participants were enrolled in the study and followed for a median of 1.4 (interquartile range 0.5-2.3) years. Most were male (73%) with a median age of 44.5 years; 13% self-identified as aboriginal. There were high levels of current injecting drug and alcohol use and poverty. Observed event rates [per 100 person-years; 95% confidence interval ( CI)] were: significant fibrosis (10.21; 8.49, 12.19), ESLD (3.16; 2.32, 4.20) and death (3.72; 2.86, 4.77). The overall standardized mortality ratio was 17.08 (95% CI 12.83, 21.34); 12.80 (95% CI 9.10, 16.50) for male patients and 28.74 (95% CI 14.66, 42.83) for female patients. The primary causes of death were ESLD (29%) and overdose (24%). Conclusions We observed excessive morbidity and mortality in this HIV/ HCV-coinfected population in care. Over 50% of observed deaths may have been preventable. Interventions aimed at improving social circumstances, reducing harm from drug and alcohol use and increasing the delivery of HCV treatment in particular will be necessary to reduce adverse health outcomes among HIV/ HCV-coinfected persons. [ABSTRACT FROM AUTHOR]

The axial and radial compressive moduli of the human meniscus are important material properties in tibiofemoral joint models, but they have not been determined previously for fresh-frozen tissue. Our goals were to measure the moduli at equilibrium and at a physiological strain rate, to determine whether the axial and radial compressive moduli are equal for each type of loading, and to determine whether they depend on the region (i.e., anterior, middle, posterior) of the meniscus. Samples from each region from 10 fresh-frozen human medial menisci were tested in unconfined compression at four strain levels (3%, 6%, 9%, and 12%) at 32%/s, a strain rate determined to be physiologically relevant to walking, and then allowed to reach equilibrium in stress relaxation. At equilibrium, the axial and radial compressive moduli at 12% strain were 83.4 kPa and 76.1 kPa, respectively ( p = 0.58), whereas at the physiological strain rate, the axial and radial compressive moduli at 12% strain were 718 kPa and 605 kPa, respectively ( p = 0.61). At the physiological strain rate, the modulus increased with increasing strain (79.2 kPa at 3% strain vs. 662 kPa at 12% strain) and the modulus in the anterior region (1,048 kPa at 12% strain) was significantly greater than that in the posterior region (329 kPa at 12% strain) ( p = 0.04). Our study supports a plane of isotropy for the material properties of meniscal tissue. However, the material behavior is strongly nonlinear because the compressive modulus is several orders of magnitude smaller than previously reported values for tensile modulus. Further, the compressive modulus depends on the activity of interest (i.e., static such as standing or dynamic such as walking) due to viscoelastic effects, the strain level, and the region of the tissue. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:951-956, 2008 [ABSTRACT FROM AUTHOR]

In the context of an epidemiological study on Potato virus Y (PVY) in potato crops, Solanum elaeagnifolium Cav. was included in the weeds prospected. Surveys were carried out in four seed potato areas: Cap Bon, Manouba, Jendouba and Kairouan. S. elaeagnifolium was found in all areas, except Cap Bon. Virus-like symptoms were observed on some S. elaeagnifolium plants in the field, i.e. leaf mottling and curling. Aphids were collected on these plants and were identified as Myzus persicae and Aphis fabae, both known to colonize potatoes and to transmit the standard PVYN isolate with transmission efficiencies of 95% and 43%, respectively. Forty-seven plant samples were tested with ELISA for the presence of PVY. Positive reactions were obtained from 2/6, 5/18, 8/23 samples collected in Manouba, Jendouba and Kairouan, respectively. Virus transmission was carried out using M. persicae as vector from two samples of each region onto plantlets of Nicotiana tabacum cv Xanthi. All inoculated plantlets displayed typical symptoms of the PVYN strain group, confirmed by serological testing using specific antibodies. This is the first report of a PVY natural infection on S. elaeagnifolium in Tunisia. The abundance of this weed, its over-wintering status and the high rate of PVY-infected plants (31.9%) allow us to deduce that S. elaeagnifolium must be considered a reservoir species of PVY under natural conditions in Tunisia and probably in other Mediterranean countries. The presence of efficient aphid vectors of PVY on this weed in crops is additional evidence that S. elaeagnifolium may become a problem by acting as a source plant for PVY spread in potato crops. [ABSTRACT FROM AUTHOR]

Three-dimensional strain fields in articular cartilage subjected to compressive loading can be determined using a recently developed MRI-based cartilage deformation by tag registration technique. The objective of this study was to determine the experimental variables that minimize the technique error, which has not been previously reported. Error (strain bias and precision) was determined using direct experiments and Monte Carlo simulations for four variables: spatial resolution, tag line spacing, applied nominal strain, and number of control points used to describe tag lines in a B-spline model. The important results include the following: (1) bias was not significantly different from zero, (2) precision increased with image resolution and with tag line spacing, (3) precision was independent of applied nominal strain, and (4) error was a minimum (absolute precision = 0.41% strain) for the following values: spatial resolution = 0.05 × 0.05 mm2; tag line spacing = 2.0 mm; control points = 6. With these results the technique can now be used in various applications while minimizing error. Magn Reson Med, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The purpose of this study was to improve understanding of the relationship between the spatial patterns of an important insect pest, the aphidMyzus persicae, and aspects of its environment. The main objectives were to determine the predominant geographical, climatic and land use factors that are linked with the aphid's distribution, to quantify their role in determining that distribution, including their interacting effects and to explore the ability of artificial neural networks (ANNs) to provide predictive models.The study focused on four spatial scales to account for the aphid data base characteristics and available land use data sets: Europe; a broad zone over Europe covering Belgium, Denmark, France, Ireland, Italy, The Netherlands, Scotland, Sweden and Wales (Regio data base coverage); North-West Europe (i.e. Belgium, France and the United Kingdom); and England with Wales.Multiple linear regression (MLR) was used to identify the variables in the Geographic location, Climate and Land use groups, that explained significant proportions of the variance inM. persicaetotal annual numbers and Julian date of first capture. A variance partitioning procedure was used to measure the fraction of the variation that can be explained by each environmental factor and of shared variation between the different factors. Finally, ANNs were employed as an alternative modelling approach for the two largest study areas, i.e. Europe and the Regio data base coverage, to determine whether the relationship between aphid and environmental variables was better described by more complex functions as well as their ability to generalize to new data.Land use variables are shown to play a significant role in explaining aphid numbers. The area of agricultural crops, in particular oilseed rape, is positively correlated withM. persicaeannual numbers. Among the climatic variables, rainfall is negatively correlated with aphid numbers and temperature is positively correlated. The geographical components also explain a significant part of aphid annual numbers. However, the variance partitioning procedure indicates that while each group has an effect, none is dominant. Aphid first capture is mainly explained by climate where rainfall tends to delay migration and warmer conditions tend to advance it. Climate accounts for the greatest part of the variance when considered separately from the other factors. The geographical and land use components also have a significant effect on first capture at each scale, but their direct contribution is negligible. The ability of the ANN models to generalize to new total numbers and phenological data compared with MLR models was less for Europe (9 and 6% increase in the variance accounted for, respectively) than for the Regio data coverage where an increase of 44% in the variance accounted for was observed.This research supports the hypothesis that climate, land use and geographical location play a role in determining patterns of aphid annual numbers and phenology. The ability of ANN models to predict aphid distribution is improved by the inclusion of temporal land use data. However, identification of the processes involved in such relationships is difficult due to numerous interactions between the environmental factors. [ABSTRACT FROM AUTHOR]

ABSTRACT The objectives of this study were: (i) to determine the stresses as a result of assembly and the stress concentration of a clamped connection, (ii) to demonstrate the importance of the effects of assembly in fatigue life predictions and (iii) to verify the accuracy of fatigue life predictions by measuring fatigue life experimentally. A stem-handlebar assembly used in off-road bicycles was chosen for the study because it is a critical assembly for which structural reliability must be insured to prevent serious injury. Assembly stresses in the handlebar exceeded 200 MPa and stress concentration because of the attached stem increased the applied stress by 40%. A stress-life prediction indicated that assembly effects would reduce predicted fatigue life of the handlebar by a factor of approximately 20. The measured fatigue lifetime of the handlebar was longer than that predicted by using the stress-life approach, but was much shorter than that predicted when assembly effects were ignored. Therefore, assembly effects have a significant effect on fatigue life predictions and should be included in lifetime assessments for clamped mechanical assemblies. [ABSTRACT FROM AUTHOR]

Background: Antibiotic prophylaxis for percutaneous endoscopic gastrostomy insertion remains controversial. The bacteriology of peristomal infection following percutaneous endoscopic gastrostomy insertion has been poorly studied, leading to uncertainty regarding the optimum choice of antibiotic for prophylaxis. Aim: To investigate the bacteriology of peristomal infection following percutaneous endoscopic gastrostomy insertion and to determine the contribution of methicillin-resistant Staphylococcus aureus. Methods: Nasal and pharyngeal swabs were taken from a consecutive series of patients prior to percutaneous endoscopic gastrostomy insertion over a 6-month period. Bacterial colonization and infection at the peristomal site were prospectively evaluated at days 2/3 and 7 post-insertion. Results: Thirty-one patients underwent percutaneous endoscopic gastrostomy insertion (mean age, 68 years; cerebrovascular disease, 52%). Naso-pharyngeal colonization by methicillin-resistant Staphylococcus aureus (35%) invariably led to peristomal colonization following percutaneous endoscopic gastrostomy insertion. Peristomal infection occurred in eight (26%) cases (seven (88%) methicillin-resistant Staphylococcus aureus- positive). Peristomal infection was significantly more likely to occur in patients with naso-pharyngeal methicillin-resistant Staphylococcus aureus colonization (odds ratio, 10.8; 95% confidence interval, 1.6–70.9). Conclusions: Naso-pharyngeal methicillin-resistant Staphylococcus aureus colonization invariably predicts peristomal methicillin-resistant Staphylococcus aureus colonization following percutaneous endoscopic gastrostomy insertion, and is associated with an increased peristomal infection rate. Currently recommended antibiotic prophylaxis regimens may be inappropriate in institutions with significant methicillin-resistant Staphylococcus aureus colonization rates. [ABSTRACT FROM AUTHOR]

This paper reports on the design, development and evaluation of a buffer algorithm named RESBAL, which exploits parallelism in order to provide high query execution performance in relational database systems. The algorithm aims to provide both predictive and efficient data buffering by exploiting the use of advance knowledge of query reference behaviour. Designed to offer a high level of flexibility, RESBAL employs a multiple buffering strategy both on page fetch level and page replacement level in order to improve buffer performance. The evaluation of RESBAL has been carried out in a parallel database system environment based on a transputer architecture. The results of this performance assessment allow comparison to be made between different buffer algorithms, and demonstrate the feasibility and effectiveness of the RESBAL algorithm. © 1998 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An extrapulmonary oat-cell carcinoma arose in the tongue of a 62-year-old man who had a long history of cigarette smoking and ethanol ingestion. At presentation, he had the primary tongue lesion and cervical lymph-node metastases only, and search for a pulmonary primary was negative. Ten months later he died with metastases to liver, cerebrum, ribs, vertebrae, calvarium, and clavicle. Electron microscopy demonstrated cells with cytoplasmic processes and many dense-core neurosecretory granules that had a tendency to concentrate in the processes. Cells were linked by desmosomes. Electron microscopy is necessary for definitive diagnosis of extrapulmonary oat-cell carcinomas. [ABSTRACT FROM AUTHOR]

Papillomavirus infects human epidermal cells and causes verruca vulgaris, which is characterized by altered epidermal growth rates and differentiation patterns. There is also a prominent induced dermal proliferative response. Ten formalin-fixed skin specimens from 10 patients, each with histologically characteristic verruca vulgaris, were excised from paraffin blocks, deparaffinized in xylene, and rehydrated in graded ethanol solutions. Hydrated specimens were incubated in 90% formic acid at 45°C for 18 h. Using a dissecting microscope the epidermis was gently separated from the dermis, which then was fixed in 3% glutaraldehyde and processed for scanning electron microscopy. Scanning electron microscopy showed a well-preserved epidermal-dermal junction (EDJ) covered by basal lamina. In comparison with normal EDJ, the EDJ of verruca vulgaris showed markedly elongated dermal papillae. Some papillae were broad and thin, and others were broad and thick. Irregularly shaped and branching secondary papillae were common. Also, there were changes in the basal lamina: the normal corrugation pattern was replaced by relatively smooth undulations or coarse, vertically oriented ridges on papillae. Papillary tips were often smooth. This study shows that there were prominent alterations in the topography of the EDJ and basal lamina in verruca vulgaris. This technique should be useful in evaluating epithelial-connective tissue morphologic interactions in formalin fixed archival tissue in other diseases characterized by alterations in epidermal growth rates and differentiation patterns. [ABSTRACT FROM AUTHOR]

The activities of five active-oxygen scavenging enzymes were compared for cold-lability and three were compared for chilling induction in two Zea genotypes of contrasting susceptibility to photoinhibition during chilling. Activities of superoxide to photoinhibition during chilling. Activities of superoxide dismutase (SOD, EC 1.15.1.1), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1), and glutathione reductase (GTR, EC 1.6.4.2.) in leaf extracts from plants grown without chilling stress were assayed at 19°C and 5°C. Enzymes from the chilling-susceptible Z. Mays LG11 had lower specific activities at 5°C than did enzymes from the chilling-tolerant Z. diploperennis, except for MDHAR where no significant differences were observed. The activities of SOD and APX from Z. diploperennis were double those of Z. mays at both assay temperatures. Monodehydroascrobate reductase and glutathione reductase activities in both species were reduced by 63-78% at a 5°C assay temperature. The dehydroascorbate reductase (DHAR) showed the greatest low-temperature lability losing 96% (Z. diploperennis) and 100% (Z. mays) of its activity at 5°C. To examine possible chilling-induced changes in levels of enzyme activity. plants of both Zea genotypes were transferred to growth chambers at 10° at moderate light intensities. Glutathione reductase activity was found to increase within 24h in Z. diploperennis, but it decreased slightly in Z. mays. MDHAR activity decreased by 50% in Z. diploperennis but showed only a transient increase in activity in Z. mays. [ABSTRACT FROM AUTHOR]

There is a perceived need within the database community to extend the traditional relational database systems so as to accommodate applications which are deductive in nature. One major problem involved in such an extension is the efficient processing of recursive queries. To this end, parallel processing is expected to play an important role. While substantial work has been done in devising strategies for processing recursive queries in parallel, it is perhaps surprising that little has been reported on the implementation and the run-time performance of these strategies. In the paper we report our experience of implementing a pipelined evaluation strategy on transputers. A wide range of queries, database structures and architectural configurations are considered as benchmarks in this study. The performance is studied in terms of both speed-up factors and communication costs. The experimental results show the potential of processing recursive queries in parallel, and provide insight into the usefulness of using transputers for such applications. [ABSTRACT FROM AUTHOR]