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Cyanobacterial mats are commonly reported as hotspots of microbial diversity across polar environments. These thick, multilayered microbial communities provide a refuge from extreme environmental conditions, with many species able to grow and coexist despite the low allochthonous nutrient inputs. The visibly dominant phototrophic biomass is dependent on internal nutrient recycling by heterotrophic organisms within the mats; however, the specific contribution of heterotrophic protists remains little explored. In this study, mat community diversity was examined along a latitudinal gradient (55-83°N), spanning subarctic taiga, tundra, polar desert, and the High Arctic ice shelves. The prokaryotic and eukaryotic communities were targeted, respectively, by V4 16S ribosomal RNA (rRNA) and V9 18S rRNA gene amplicon high-throughput sequencing. Prokaryotic and eukaryotic richness decreased, in tandem with decreasing temperatures and shorter seasons of light availability, from the subarctic to the High Arctic. Taxonomy-based annotation of the protist community revealed diverse phototrophic, mixotrophic, and heterotrophic genera in all mat communities, with fewer parasitic taxa in High Arctic communities. Co-occurrence network analysis identified greater heterogeneity in eukaryotic than prokaryotic community structure among cyanobacterial mats across the Canadian Arctic. Our findings highlight the sensitivity of microbial eukaryotes to environmental gradients across northern high latitudes., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

Objective: To determine factors associated with the length of stay (LOS) for patients with suspected community-acquired pneumonia (CAP) who required hospitalization for treatment., Study Design: The authors studied a population-based prospective cohort of 2,757 adults with suspected CAP who were admitted over a two-year period. Logistic regression, multiple linear regression, and classification and regression trees were used to determine the factors associated with LOS., Setting: The study was conducted in two community and tertiary care hospitals, two community and secondary care hospitals, and two community hospitals in the Capital Health Region of Edmonton, Alberta., Results: Symptoms such as sweats, shaking chills and wheezing were associated with an LOS of seven days or shorter, whereas weight loss, functional impairment, heart, renal or neoplastic diseases and time to first dose of antibiotic were predictive of an LOS greater than seven days. Regression tree analysis indicated that rapid achievement of physiological stability was associated with a shorter LOS. The use of an indwelling urinary catheter was found to be an important determinant of LOS., Conclusions: The present study found several new associations with increased LOS in patients with CAP, including functional status, time to receipt of first dose of antibiotic therapy, use of certain antibiotics, presence of a urinary catheter and the importance of time to physiological stability. An intervention targeting avoidance of urinary catheters may be associated with a shorter LOS.

A model for foetal growth is developed and used to construct tools for diagnosis of intrauterine growth restriction. Foetal weight estimates are first transformed to normally distributed z-scores. The covariance structure over gestational ages is then estimated using a novel regression model. The diagnostic tools include individual growth curves with error bounds, probabilities to assess whether a foetus is small for its gestational age, and residual scores to determine whether current growth rates are unusual. The methods were developed sing data from 13593 ultrasound examinations involving 7888 foetal subjects. The model shows that median foetal growth velocity increases up to a gestational age of 35 weeks and then decreases during the final weeks of pregnancy. When growth is expressed as change in log weight, or equivalently as change proportional to current weight, the model reveals a constant deceleration as gestational age increases from 14 to 42 weeks., (Copyright 2002 John Wiley & Sons, Ltd.)

Motivation: Current software tools are moderately effective in predicting genetic structure (exons, introns, intergenic regions, and complete genes) from raw DNA sequence data. Improvements in accuracy and speed are needed to deal with the increasing volume of data from large scale sequencing projects., Results: We present a two-stage computer program to predict genetic structure in eukaryotic DNA. The first stage makes use of a novel statistical technique, called reference point logistic (RPL) regression, to calculate scores for potential functional sites. These site scores are combined with interval content, length, and state scores, via a Generalized Hidden Markov Model, to determine a combined score for each possible parse of a given DNA sequence into exons, introns, and intergenic regions. An optimal parse is found using a dynamic programming algorithm. In the second stage, protein sequence alignment methods are applied to improve the accuracy of the initial parse. Computation in the first stage of the program is very fast (1 s on a 360 MHz CPU for a 16 kb sequence) and its predictive accuracy typically matches or exceeds the best results reported for other methods (Sensitivity = 0.93 and Specificity = 0.93 for the Burset/Guigótest set). Computation in the second stage is slower, but the final predictions are more accurate (Sn = 0.97, Sp = 0.97). The program (called GRPL) can handle partial, single, and multi-gene sequences. The program is also capable of predicting the genetic structure of vertebrate, invertebrate, and plant DNA with nearly equal accuracy. Statistical techniques have also been introduced to model the effects of varying C+G content in a continuous manner and to control overfitting of parameters for smaller training sets., Availability: An academic implementation of GRPL, compiled for SUN workstations, is available by anonymous ftp from snipe.pharmacy. ualberta.ca/pub. The training and test sets used in this work, together with supplementary material, can be found at the same location. A commercial implementation is available as a component of GeneTool (BioTools Inc., http://biotools.com).

Border molding is an important step in the fabrication of complete dentures. Conventional border molding using impression modeling plastic has been time-consuming and has resulted in a great variation in the shape of the recorded borders. This study compared the shape and variability of the vestibular impressions made with impression modeling plastic and a polyether impression material. Four prosthodontists each made five maxillary vestibular impressions using the two materials. All the impressions were made on one edentulous subject. The results showed significant differences at many locations along the border of the impressions. The borders of the impressions made with modeling plastic tended to be thicker and shorter than those made using polyether material. Use of the polyether material required less time to complete the border molding procedures and demonstrated a more consistent result in the shape of the vestibular impressions.

This study evaluated the effect of disinfection time (10, 30 and 60 minutes) on the dimensional changes of stone casts poured against an irreversible hydrocolloid impression material (Jeltrate). Impressions were made of a stainless steel analog of a maxillary arch. The impressions were sprayed with bleach, iodophor, phenol, and water and were stored for designated times before poured in a type IV stone (Vel-mix). The arch width, length, and depth of the vault of the resultant casts were measured by use of a contact measuring device (MicroVal) capable of measuring to 0.0001 mm. Data were analyzed with two-way analysis of variance at the 95% confidence level. Results indicated that disinfection treatment of alginate impressions with surface disinfectants did not cause significant dimensional changes in the resultant stone casts from statistical and clinical points of view.

This study evaluated the effects of disinfection time (10, 30, and 60 minutes) on the surface quality of stone casts poured against an alginate impression material (Jeltrate). Five antimicrobial agents were tested: Sporicidin spray, sodium hypochlorite, and iodophor for spray; and Sporicidin cold sterilization solution and Cidexplus glutaraldehyde solution for immersion. Impressions, flushed with water and stored for 0, 10, 30, and 60 minutes before pouring, served as untreated controls. On completion of the disinfection treatments, the impressions were rinsed and poured in Velmix stone. The effects on cast surface were evaluated under a stereomicroscope by three experienced raters. A 1-to-4 scoring system was developed to rate the surface quality in terms of smoothness and detail reproduction. Both immersion disinfectants proved to be unacceptable for treating alginate impressions. The mean scores of other disinfectant-time combinations were compared with the use of the Tukey-Kramer method with a 95% confidence interval. The results indicated that treatment time had statistically significant effects on the quality of cast surface in Sporicidin spray, sodium hypochlorite, and untreated control groups but not in the iodophor spray group.

An interactive computer program has been developed to align a three-dimensional region of interest (ROI) model to technetium-99m-hexamethylpropylenamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) studies of the brain. The ROI model subdivides the human brain into fourteen discrete regions. A study was performed to determine normal ranges for HMPAO uptake in the ROIs defined by the model, and to assess the relative interobserver variability using the fitting program. HMPAO SPECT studies of twelve normal volunteers were independently analyzed by four observers. Small but significant differences between operators occurred primarily because of difficulty in defining the angle of the orbitomeatal plane on sagittal SPECT images. Despite this difficulty, the program and model have proven useful in defining ranges for normal cerebral perfusion in a healthy adult population. A study of a small group of patients with Alzheimer's dementia suggests that this procedure may be of use in the diagnosis of this disease.