[The relationship between oral microbiota and taste]. / De relatie tussen mondmicrobiota en smaak.

Disruption of the perception of taste can have severe consequences on general health. Although evidence suggests that the oral microbiota plays a role in taste perception, little is known about this possible influence. In this scoping review, the influence of oral microbiota on taste perception was studied. Current scientific literature is heterogeneous in study methods and study populations, which impedes comparison of results. Although the findings of this review provide insufficient evidence to confirm the influence of oral microbiota on taste perception, some results show a relationship between taste perception and specific microorganisms. Several factors play a role in taste perception, including tongue coating, use of medication, advanced age, and decreased salivary flow rate, and when these factors are present, it is important to be alert to possible changes in taste. Large-scale studies, in which the multifactorial etiology of taste perception is addressed, are needed to clarify the role of the oral microbiota on taste perception.

Summer temperatures reach the thermal tolerance threshold of photosynthetic decline in temperate conifers.

Climate change-related environmental stress has been recognized as a driving force in accelerating forest mortality over the last decades in Central Europe. Here, we aim to elucidate the thermal sensitivity of three native conifer species, namely Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver fir (Abies alba), and three non-native species, namely Austrian pine (Pinus nigra), Douglas fir (Pseudotsuga menziesii) and Atlas cedar (Cedrus atlantica). Thermal sensitivity, defined here as a decline of the maximum quantum yield of photosystem II (Fv /Fm ) with increasing temperature, was measured under varying levels of heat stress and compared with the turgor loss point (πtlp ) as a drought resistance trait. We calculated three different leaf thermotolerance traits: the temperature at the onset (5%) of the Fv /Fm decline (T5), the temperature at which Fv /Fm was half the maximum value (T50) and the temperature at which only 5% Fv /Fm remained (T95). T5 ranged from 38.5 ± 0.8 °C to 43.1 ± 0.6 °C across all species, while T50 values were at least 9 to 11 degrees above the maximum air temperatures on record for all species. Only Austrian pine had a notably higher T5 value than recorded maximum air temperatures. Species with higher T5 values were characterized by a less negative πtlp compared to species with lower T5. The six species could be divided into 'drought-tolerant heat-sensitive' and 'drought-sensitive heat-tolerant' groups. Exposure to short-term high temperatures thus exhibits a considerable threat to conifer species in Central European forest production systems.

Detailed images of asteroid 25143 Itokawa from Hayabusa.

Rendezvous of the Japanese spacecraft Hayabusa with the near-Earth asteroid 25143 Itokawa took place during the interval September through November 2005. The onboard camera imaged the solid surface of this tiny asteroid (535 meters by 294 meters by 209 meters) with a spatial resolution of 70 centimeters per pixel, revealing diverse surface morphologies. Unlike previously explored asteroids, the surface of Itokawa reveals both rough and smooth terrains. Craters generally show unclear morphologies. Numerous boulders on Itokawa's surface suggest a rubble-pile structure.

The recent expansion of Pluto's atmosphere.

Stellar occultations--the passing of a relatively nearby body in front of a background star--can be used to probe the atmosphere of the closer body with a spatial resolution of a few kilometres (ref. 1). Such observations can yield the scale height, temperature profile, and other information about the structure of the occulting atmosphere. Occultation data acquired for Pluto's atmosphere in 1988 revealed a nearly isothermal atmosphere above a radius of approximately 1,215 km. Below this level, the data could be interpreted as indicating either an extinction layer or the onset of a large thermal gradient, calling into question the fundamental structure of this atmosphere. Another question is to what extent Pluto's atmosphere might be collapsing as it recedes from the Sun (passing perihelion in 1989 in its 248-year orbital period), owing to the extreme sensitivity of the equilibrium surface pressure to the surface temperature. Here we report observations at a variety of visible and infrared wavelengths of an occultation of a star by Pluto in August 2002. These data reveal evidence for extinction in Pluto's atmosphere and show that it has indeed changed, having expanded rather than collapsed, since 1988.

An algorithm for finding the linear region in a nonlinear data set.

Finding the linear reportable range is an important procedure for each method in clinical chemistry. One is often called upon to limit the reportable range in order to find the linear region. Limiting the reportable range by visual techniques is subjective, may introduce bias and is not programmable. Using Kroll and Emancipator's polynomial method for linearity, we compare the residuals of a test to determine whether eliminating a point from one end or the other of the data set worsens or improves the data sets' linearity. In an example of urinary cortisol, the root mean squares of the residuals improve by 2% when the lowest point is removed, 39% when the highest point is removed and 82% when the two highest points are removed. The latter data set is the most linear.

The usefulness of calibration verification and linearity surveys in predicting acceptable performance in graded proficiency tests.

OBJECTIVE: To assess the association between performance on graded chemistry surveys and evaluation of linearity and calibration in Linearity surveys. DESIGN: Data from Linearity Surveys (LN series) and from routine comprehensive College of American Pathologists chemistry surveys (all series) were used to evaluate the hypothesis that laboratories with nonlinear or univerified calibration would have a greater likelihood of unacceptable performance on comprehensive chemistry surveys. RESULTS: This study found that acceptable calibration verification evaluation is significantly related to acceptable rates for most analytes, including albumin, calcium, chloride, glucose, iron, magnesium, sodium, total bilirubin, uric acid, high-density lipoprotein cholesterol, triglycerides, alkaline phosphatase, alanine and aspartate aminotransferase, digoxin, gentamicin, phenobarbital, procainamide, and thyroxine. CONCLUSION: There is a consistent and strong relationship between calibration verification problems in the Linearity Surveys and failure rates in the College of American Pathologists chemistry surveys. Laboratories with poor calibration evaluations on Linearity Surveys have higher unacceptable rates on proficiency tests. Individual laboratories who were rated linear and whose calibration was verified by Linearity Surveys have lower unacceptable rates.

Proficiency test performance and experience with College of American Pathologists' programs.

We examined rates of unacceptable results in a large interlaboratory proficiency test program, which is designed for small hospitals, clinics, and physician offices. The objective was to see whether rates of unacceptable results decrease as laboratories gain experience in interlaboratory comparison programs. We examined data from the College of American Pathologists' Excel Surveys, 1987 through 1993, in the areas of chemistry, hematology, immunology, and blood bank. The data for laboratories with consistent participation show consistent and statistically significant improvement in performance for the first 3 to 4 years of proficiency testing. The data for all participants also suggest that laboratories with more experience with proficiency testing have lower rates of unacceptable results, and that these rates tend to decrease with each year of experience. These conclusions support the findings of other researchers who have documented the benefits of interlaboratory comparison programs and proficiency testing.

Reference values and participant means as targets in proficiency testing.

Regulatory agencies will be placing greater reliance on the results of proficiency testing (PT) for determining licensing status of individual laboratories. This has caused a renewed interest in the process used by proficiency test providers for determining the correct result for each proficiency test challenge. Three general techniques have been proposed and would be allowed under the regulations: (1) participant-derived targets (means from a specific group of participants); (2) targets from a set of "reference" laboratories, from either a subset of participants or a selected group of experts using a rigorous experimental protocol; or (3) definitive values from a single source. The College of American Pathologists (CAP) has used all three techniques at different stages and for different purposes in the history of the CAP Surveys programs. This article reviews the early experiences of the CAP, the evolution of the current protocol, and activities to monitor the accuracy of target values. Participant-derived "consensus" results have been shown to be highly accurate and reliable. The CAP uses definitive methods at the National Institute for Standards and Technology and certified reference materials to monitor the validity of targets used in proficiency testing.

Alternative statistical techniques to evaluate linearity.

With the increase in demand for linearity assessment, a wide variety of analysis techniques have been advocated. There is no consensus on optimal techniques. This article reviews different approaches that have been advocated by the College of American Pathologists, by the National Committee for Clinical Laboratory Standards, and by manufacturers of diagnostic methods and controls. This is not a review of all statistical techniques proposed for linearity assessment. I discuss four basic categories of methods, with the first and simplest being visual review. The second general approach includes the conventional statistical techniques based on least-squares regression; this includes an equation for the line and statistical tests for linearity and for curvature. The third general approach involves comparison of slopes for line segments, or "deltas." This approximates the visual assessment of linearity. The fourth approach involves comparing observed and expected values, with some allowance for differences. Comparisons can be made for observed single results, means of replicates, or components of variance. Allowances for error can be internal goals or goals that are recommended for clinical usefulness. Each approach has strengths in different aspects of linearity assessment, including intuitive appeal, statistical rigor, and objectivity. Similarly, each approach has limitations that are not always obvious.

Academic manpower survey of 1990: II. Kinetics in the United States (from the Joint Task Force on Pathology Manpower ASCP/CAP/APC).

Survey data obtained from chairmen of United States departments of pathology shows a continued shortage of faculty, especially those with the MD or MD/PhD degree. Losses of such faculty by responding departments during the 12 months prior to the survey were distributed as follows: retirement, 40 (15.6% of total); disability/death, 19 (7.4%); termination, 23 (8.9%); resignation, 172 (69.3%); and other, 3 (1.2%). Resignations were due primarily to decisions to join another university (41.4%) or to enter private practice (42.5%); a small proportion were due to individuals who left academe for a pathology position in government or industry, or left both academe and pathology for another field. Comparison with a similar survey performed in 1984 suggests that the manpower situation in academic pathology is worsening, especially with respect to physician faculty. An assessment of those factors known to influence manpower kinetics suggests that it will continue to deteriorate for the foreseeable future with an adverse impact on all sectors of pathology.

Academic manpower survey of 1990: I. Descriptors of departments of pathology in the United States (from the Joint Task Force on Pathology Manpower ASCP/CAP/APC).

A survey of chairmen of United States departments of pathology (97% response rate) augmented with data from the Association of American Medical Colleges shows that roughly two thirds (65%) of departmental faculty are physicians, the great majority of whom are pathologists. Most of the remainder are persons with solely the PhD degree (26.4% of faculty). The composition of departments of pathology in terms of age, gender, ethnic origin, academic rank, and tenure status is also reported. In contrast to a comparable survey performed 5 years previously, the present report shows that in 1989, departments of pathology contained (1) 20.6% more faculty positions, (2) a greater proportion of faculty members with a PhD degree, (3) greater numbers of open positions, and (4) a probable increase in the proportion of faculty that are female and that are of an ethnic minority.

Solid C triple bond N bearing material on outer solar system bodies.

Using telescopic observations by ourselves and other observers, we have identified cyano-group containing molecules in the very dark solids on the surfaces of a few D-class asteroids, the dust of some comets, and low-albedo hemisphere of Iapetus, and the rings of Uranus, through spectroscopic detection of the 2.2-micrometers overtone of the C triple bond N stretching fundamental mode. The occurrence of this band on all four classes of small Solar System bodies may be diagnostic of the duration of exposure and degree of modification of surface materials, and may also establish a link between outer Solar System and interstellar materials.

National Pathology Manpower Survey of 1988. Manpower needs in community hospitals and private laboratory practice.

The survey of manpower in community hospital and private laboratory practice of pathology of 1988 presented herein verifies the conclusions of the 1986 survey that a growing deficit of manpower in this sphere of practice is highly likely in the next few years. It appears that the deficit will be even larger than that predicted by the 1986 survey. Steps are urgently needed to increase the flow of graduating medical students, especially those of top quality, into our specialty.

Some characteristics of the community practice of pathology in the United States. National Manpower Survey of 1987.

An evaluation of 629 pathologists engaged in community hospital and private laboratory practice and representing 601 pathology practices of varying size shows surprising uniformity in the distribution of professional effort. On average, pathologists in community practice distribute their effort as follows: surgical pathology, 34.6%; autopsy pathology, 6.7%; cytology, 8.8%; clinical pathology, 18.0%; teaching, 6.0%; research and development, 2.3%; laboratory administration, 17.5%; hospital administration, 2.9%; and other, 3.2%. The average community pathologist is male, 52 years of age, and a graduate of an American medical school (60%). When surveyed in 1986, community pathologists worked an average of 50 hours per week and retired at an average age of 62 years.

Special report--National Manpower Survey of 1987. Manpower needs in community hospital and private laboratory practice of pathology.

A new survey of manpower requirements in the community hospital and private laboratory practice of pathology has been completed and analyzed. The survey used a new instrument, the National Pathology Manpower Database, which will be useful in conducting longitudinal surveys. This instrument will permit organized pathology to monitor changes in pathology manpower needs in the years ahead, which are likely to be fraught with change. The results of this survey foretell a significant deficit of pathologists in community hospital and private laboratory practice within the next five years.

Proficiency testing of enzymes. Charting the way toward standardization.

Laboratories participating in the College of American Pathologists Enzyme Survey (ES) and Comprehensive Chemistry Survey used diverse methods for the same analyte, resulting in a considerable range of values for the commonly performed enzyme measurements. Nevertheless, with the techniques developed for the ES, both the short-term (within-mailing) and long-term (between-mailings) coefficients of variation (CVs) can be determined. The ten-year experience of the ES has shown improvement in the short-term CV; however, long-term stability of enzyme testing requires more effort on the part of the instrument and reagent suppliers and participating laboratories. A reference material with an International Federation of Clinical Chemistry-established aspartate aminotransferase value, National Bureau of Standards RM 8430, is now available and was sent to three large peer groups as part of a special study. Correction of the results to the RM 8430 aspartate aminotransferase value resulted in reducing the range of data from peers using the duPont aca but not from those using the American Monitor KDA or Technicon SMAC. Based on our experience with the ES, goals of 5% for the short-term CV and 10% for the long-term CV are proposed; they are achievable by most laboratories and meet medical needs for biochemical screening. Fixed criteria for the evaluation of enzyme results appear to be appropriate given the way most enzyme data are used clinically.

A nonparametric analysis method for evaluation of survey results. Application to ligand assay survey.

A nonparametric analysis method that does not depend on gaussian data distributions is proposed for evaluation of proficiency survey results. The proposed method also provides a mechanism for processing results qualitatively reported as "less than" or "greater than" pre-established limits of quantitation. The evaluation limits for acceptability are calculated to include the central 95% of all test results from all methods. Systematic differences in the levels of analyte concentrations caused by differences in analytical measurement systems are normalized by mathematically transforming the test results from each analytic method by dividing them by their method-specific group median. This nonparametric method was compared with the traditional mean +/- 2 SD limits using data collected for digoxin, free thyroxine, and quantitative chorionic gonadotropin measurement in the College of American Pathologists Ligand Assay Survey. The nonparametric method more accurately classified 5% of the results as "unacceptable." When more than 2.5% of the test results for a method were designated as "less than," no lower limit was used for evaluation and only 2.5% of results were classified as "unacceptably high." The current College of American Pathologists procedure favors analytical methods with larger coefficients of variation by setting wider limits of acceptability, while the proposed procedure favors methods with smaller coefficients of variation.

Multiprogram characterization of laboratory bias, precision, and total error. Proposal for improved assessment with shared external and expanded internal (regional) quality control pools.

We establish that, for the analytes aspartate aminotransferase, glucose, phosphorus, and potassium, there is significant correlation between laboratory performance as determined by College of American Pathologists-sponsored external (Surveys) and expanded internal (regional) quality control (Quality Assurance Service) programs. However, relatively low parametric and nonparametric correlation coefficients and significant departure of linear regression slopes from unity reflect major differences in the calculated parameters of absolute bias, precision, and total error obtained through internal and external quality control. Significantly better performance in both Surveys and the Quality Assurance Service was documented for laboratories participating in the College of American Pathologists Laboratory Accreditation Program. Multiple descriptors of laboratory quality, as indicated here, are superior in describing laboratory performance to proficiency testing alone. As a bridge between external and internal quality control, shared pools of quality control materials are described for use as unknown Survey challenges and subsequent distribution for regional quality control. Such programs, which can be configured to serve thousands of laboratories, could offer cost savings, better quality assurance, and improved characterization of laboratory performance by minimizing interprogram differences in control matrix and method classification and providing greater reliability of target values.

A statistical procedure for measuring and evaluating performance in interlaboratory comparison programs.

There are scientific and regulatory needs to measure individual laboratory performance on a series of challenges, for single analytes and for all analytes in a particular discipline. Because these needs must be met with a very limited amount of information, optimal statistics should be used to measure performance. Since punitive action could result from poor performance, there should be precise quantitative goals that can be measured directly with the performance statistic. Finally, it is important to limit the likelihood of falsely penalizing a laboratory, since the large majority of laboratories are not in need of regulatory action. A statistic is described that measures individual performance on quantitative interlaboratory proficiency tests. This statistic is based on actual error relative to the amount of error that is tolerable. It can be accumulated over several challenges (specimens tested as unknowns) to give an estimate of a participant's performance level for that analyte. It can also be accumulated across analytes to give scores for Survey mailings or for accumulated performance. Because the statistic measures error, it contains more information than does the percentage of acceptable results, and therefore has greater power to detect poor performance. The distribution of the statistic is described and tested for validity. Then, a procedure is presented to evaluate laboratories relative to a performance goal. The entire procedure is then tested with recent College of American Pathologists Chemistry Survey data.