bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple-Bias Modelling for Analysis of Observational Data
Authors: Greenland Sander 
Published: March 2005

SummaryConventional analytic results do not reflect any source of uncertainty other than random error, and as a result readers must rely on informal judgments regarding the effect of possible biases. When standard errors are small these judgments often fail to capture sources of uncertainty and their interactions adequately. Multiple-bias models provide alternatives that allow one systematically to integrate major sources of uncertainty, and thus to provide better input to research planning and policy analysis. Typically, the bias parameters in the model are not identified by the analysis data and so the results depend completely on priors for those parameters. A Bayesian analysis is then natural, but several alternatives based on sensitivity analysis have appeared in the risk assessment and epidemiologic literature. Under some circumstances these methods approximate a Bayesian analysis and can be modified to do so even better. These points are illustrated with a pooled analysis of case–control studies of residential magnetic field exposure and childhood leukaemia, which highlights the diminishing value of conventional studies conducted after the early 1990s. It is argued that multiple-bias modelling should become part of the core training of anyone who will be entrusted with the analysis of observational data, and should become standard procedure when random error is not the only important source of uncertainty (as in meta-analysis and pooled analysis).
Uncertainty and Sensitivity Analysis Techniques as Tools for the Quality Assessment of Composite Indicators
Authors: Saisana M. , Saltelli A. , Tarantola S. 
Published: March 2005

SummaryComposite indicators are increasingly used for bench-marking countries’ performances. Yet doubts are often raised about the robustness of the resulting countries’ rankings and about the significance of the associated policy message. We propose the use of uncertainty analysis and sensitivity analysis to gain useful insights during the process of building composite indicators, including a contribution to the indicators’ definition of quality and an assessment of the reliability of countries’ rankings. We discuss to what extent the use of uncertainty and sensitivity analysis may increase transparency or make policy inference more defensible by applying the methodology to a known composite indicator: the United Nations's technology achievement index.
On the Viral Safety of Plasma Pools and Plasma Derivatives
Authors: Vansteelandt S. , Goetghebeur E. , Thomas I. , Mathys E. , Van Loock F. 
Published: March 2005

SummaryIn the industrialized world, a range of medicinal products are manufactured on a large scale from pools made of thousands of human blood and plasma donations. Policy makers as well as the general public are aware of the hazards of contamination following accumulated risks of individual donations. Today, the manufacturing process must therefore consider a complex sequence of risk reducing interventions, including screening tests and quarantine periods on pools and individual donations. We estimate the residual risk of hepatitis C infection following such sequences of events. This is the most common blood-borne infection in the western world, which affects an estimated 170 million people worldwide. We investigate the benefits and drawbacks of each intervention and study at several stages the dependence of the screening process on operational parameters that can be optimized, such as the number of donations from different donors in the pool and the length of the quarantine period. This leads to alternative risk reducing strategies that may be more (cost) effective or optimal under specific criteria.
Unemployed Couples: The Labour Market Effects of Making Both Partners Search for Work
Authors: Dorsett Richard 
Published: March 2005

SummaryThe paper evaluates the effect of a recent change to unemployment benefit in the UK which requires both partners in a couple (rather than just one) to search for work. The difference-in-differences estimator is extended in two ways. First, variations in when the change was implemented are exploited to test and adjust for bias resulting from differential trends among the control group. Second, the approach is combined with matching to relax functional form restrictions. After several months, positive effects on exiting from benefits were detected but effects on entry to jobs were less apparent.
Measuring the Efficiency of Public Services: The Limits of Analysis
Authors: Smith Peter C. , Street Andrew 
Published: March 2005

SummaryPolicy makers are increasingly seeking to develop overall measures of the effi-ciency of public service organizations. For that, the use of ‘off-the-shelf’ statistical tools such as data envelopment analysis and stochastic frontier analysis have been advocated as tools to measure organizational efficiency. The analytical sophistication of such methods has reached an advanced stage of development. We discuss the context within which such models are deployed, their underlying assumptions and their usefulness for a regulator of public services. Four specific model building issues are discussed: the weights that are attached to public service outputs; the specification of the statistical model; the treatment of environmental influences on performance; the treatment of dynamic effects. The paper concludes with recommendations for policy makers and researchers on the development and use of efficiency measurement techniques.
Clinical assessment of oral malodor intensity expressed as absolute value using an electronic nose
Authors: Nonaka A , Tanaka M , Anguri H , Nagata H , Kita J , Shizukuishi S 
Published: March 2005

Objectives:  In our previous study, scores determined via a multiple linear regression method (EN‐MLR) involving an electronic nose provided objective halitosis‐related measurements; however, this model afforded only relative expression exclusively. The objective of this investigation was to assess clinically oral malodor intensity expressed as an absolute value using an electronic nose.Subjects and methods:  Sixty‐six subjects were evaluated based on results of an actual organoleptic test (OLT), measurements of volatile sulfur compound (VSC) concentrations, a score representing malodor intensity (EN‐MI) as the absolute value and EN‐MLR measured with an electronic nose system. Oral health parameters were also examined.Results:  The OLT score served as a benchmark. The area under the receiver‐operating characteristic (ROC) plots of EN‐MI score (0.975) was significantly larger than that of log VSC (0.896) (P = 0.036); however, the area did not differ significantly from that of EN‐MLR score (0.932). Percentage of teeth with pocket depth ≥4 mm, tongue coating score and plaque control record displayed meaningful association with EN‐MI score in multiple logistic regression analyses.Conclusion:  Oral malodor intensity expressed as an absolute value employing an electronic nose may be a suitable method for clinical evaluation of oral malodor.
Use of n‐butanol as an odorant to standardize the organoleptic scale of breath odour judges
Authors: Saad S , Greenman J , Duffield J , Sudlow K 
Published: March 2005

Objective:  The alcohol n‐butanol has been recommended for use as a standard odorant by various groups for the training or standardization of breath odour judges and sensory evaluation panels. The objective of this study is to assess the use of n‐butanol as a suitable odorant for organoleptic training of breath judges.Methods:  One judge with full smell acuity was trained in the method of organoleptic assessment using odorant solutions of main chemical classes (acids, amines, indole and sulphides) with the exception of alcohols. The subject was proficient in scoring odorant solutions, standard gas mixtures and human breath using the Rosenberg 0–5 organoleptic scale. A wide range of n‐butanol solutions were prepared from 0 to 90 000 ppm and dispensed as replicate 12‐ml volumes in Universal bottles (24 ml) leaving a headspace of 12 ml. Sets of odorants were prepared, labelled by code, randomized and presented to the judge in a completely blind fashion. The judge scored each concentration. This process was repeated on 32 occasions over a period of 12 weeks. Mean values of data for each determination for each concentration series were plotted against the log concentrations of odorant. Linear regression slope analysis was used to measure slope, the 95% CI of slope and the scatter of points (R2 value). Headspace concentrations of odorant were determined using gas chromatography (GC) analysis.Results:  The n‐butanol regression slope gave a high R2 value (0.971) and low scatter. However, the data did not correspond to other published work using an ASTM method where the range of recommended butanol concentrations was insufficient at both the high and low ends to determine the top and threshold. Moreover, headspace analysis using GC confirmed the published gas concentrations to be in error by a factor of 100. It was also observed that high concentrations of odorants were irritant causing desensitization if used for prolonged periods.Conclusion:  The published method had erroneous headspace calculations listed and n‐butanol could not be recommended as a training odorant because of its irritancy.
Breath odor evaluation by detection of volatile sulfur compounds – correlation with organoleptic odor ratings
Authors: Hunter CM , Niles HP , Vazquez J , Kloos C , Subramanyam R , Williams MI , Cummins D , Lenton PA , Majerus GJ 
Published: March 2005

Background:  Detection of oral volatile sulfur compounds (VSC) by gas chromatography (GC) is a widely used method for evaluating breath odor. Air aspirated from the mouth is injected into the GC column for analysis. To eliminate discrepancies caused by variations in operator sampling or injection techniques, a new GC system designed to aspirate breath samples directly into the GC was developed.Objective:  A clinical study was performed to compare this new automated breath‐sampling GC system to organoleptic evaluation by two trained odor judges.Methods:  A randomized, two‐cell, double‐blind, parallel design was used in which subjects were tested before and 3 h after using either a mouthrinse containing zinc or a matching placebo rinse. Thirteen subjects used the zinc mouthrinse, and 12 used the placebo. Subjects with a wide range of VSC levels were studied. The average organoleptic ratings for each subject at each time‐point were compared with the average VSC measurements made with the GC, and Pearson product–moment correlation coefficients between the corresponding GC and organoleptic measurements were determined.Results:  The correlation between the GC and organoleptic assessment methods were highly significant (P ≤ 0.001) for: total VSC, 0.65; H2S, 0.63; CH3SH, 0.61; and (CH3)2S, 0.46. The correlation between the two judges was also highly significant (0.823, P < 0.001).Conclusion:  These results demonstrate the utility of the automated GC method for evaluating breath odor.
The clinical comparison of a triclosan/copolymer/fluoride dentifrice vs a breath‐freshening dentifrice in reducing breath odor overnight: a crossover study
Authors: Niles HP , Hunter C , Vazquez J , Williams MI , Cummins D 
Published: March 2005

Objective:  The objective of this randomized, crossover study was to compare the effectiveness of the triclosan/copolymer/sodium fluoride (TCF‐AF) dentifrice and a commercially available breath‐freshening dentifrice containing fluoride for their ability to reduce volatile sulfur compounds (VSC) associated with oral malodor overnight.Methods:  Following a 1‐week washout period of brushing with a regular fluoride dentifrice, subjects reported to the clinical site without performing oral hygiene, eating or drinking in preparation for baseline breath sampling. Subjects were randomly assigned a test dentifrice and instructed to brush their teeth for 1 min, twice a day for 1 week. On the morning of day 8, subjects returned to the test site, having refrained from oral hygiene, eating and drinking, for overnight sampling. Following a second 1‐week washout period, subjects repeated the same regimen, but now using the other test product. At each measurement, the level of breath VSC was evaluated using a gas chromatograph equipped with a flame photometric detector. Measurements were taken in duplicate, and then averaged. The levels of VSC were expressed as parts per billion (ppb) in mouth air.Results:  At baseline, the mean breath VSC levels for the TCF‐AF and breath‐freshening dentifrice were 618 and 581 ppb respectively. There was no statistically significant difference between the baseline levels. Overnight, the TCF‐AF and the breath‐freshening dentifrice reduced breath mean VSC levels to 267 and 521 ppb respectively. This gave a 56.7 and 10.2% reduction in VSC levels for these two products, respectively, compared with baseline. The reduction for the TCF‐AF dentifrice was significantly different (P < 0.05%) from that of the breath‐freshening dentifrice.Conclusion:  The results of this randomized, double‐blind, crossover study indicate that the TCF‐AF dentifrice was significantly more effective than a commercially available breath‐freshening dentifrice containing fluoride in reducing breath VSC associated with bad breath overnight.
Microbiological culture analysis of the tongue anaerobic microflora in subjects with and without halitosis
Authors: Donaldson AC , McKenzie D , Riggio MP , Hodge PJ , Rolph H , Flanagan A , Bagg J 
Published: March 2005

Objective:  Determination of the microflora present on the tongue dorsum of subjects with and without halitosis using conventional microbiological culture methods.Methods:  Twenty‐one halitosis and 20 control patients were recruited using a strict clinical protocol. Samples were collected from the posterior dorsum of the tongue using a sterile brush. Each sample was vortex mixed for 30 s and serial 10‐fold dilutions to 10−7 were carried out. Samples were plated onto fastidious anaerobe agar (FAA) and FAA enriched with vancomycin. These were incubated under anaerobic conditions for 10 days at 37°C. Strict anaerobes were identified by metronidazole sensitivity and bacteria were identified to genus level by a combination of colony morphology, Gram staining and biochemical and enzymatic tests (rapid ID 32 A).Results:  The predominant species in test and control groups were Veillonella sp. and Prevotella sp. Greater species diversity was found in the halitosis samples compared with controls. The halitosis samples contained an increased incidence of unidentifiable Gram‐negative rods, Gram‐positive rods and Gram‐negative coccobacilli.Conclusions:  There was no obvious association between halitosis and any specific bacterial genus. The increased species diversity found in halitosis samples suggests that halitosis may be the result of complex interactions between several bacterial species. The role of uncultivable bacteria may also be important in contributing to this process.
Clinical efficacy of a triclosan/copolymer/NaF dentifrice and a commercially available breath‐freshening dentifrice on hydrogen sulfide‐forming bacteria
Authors: Vazquez J , Pilch S , Williams MI , Cummins D 
Published: March 2005

Objective:  The objective of this randomized, cross‐over clinical study was to compare the 4‐h and overnight effects of a triclosan/copolymer/fluoride (TCF‐AF) dentifrice and a commercially available breath freshening (CBF) dentifrice containing fluoride for their ability to control H2S‐forming bacteria.Methods:  Following a 1 week washout period of brushing with a regular fluoride dentifrice, subjects reported to the clinical site without performing oral hygiene, eating or drinking in preparation for baseline saliva sampling. After providing a baseline saliva sample, subjects were randomly assigned a test dentifrice and instructed to brush their teeth for 1 min, twice a day for 1 week. On the morning of the eighth day, subjects returned to the test site having refrained from oral hygiene, eating and drinking for overnight sampling. Subjects then brushed for 1 min with the assigned dentifrice, and returned for 2 and 4 h postbrushing evaluations. Following a second 1 week washout, subjects repeated the same regimen, but now using the other dentifrice. Oral micro‐flora samples were collected by subjects rinsing with 10 ml of sterile water for 10 s. Each collected sample was serially diluted and plated in duplicate onto lead acetate agar. After incubating for 72 h, dark colonies were counted, expressed as log colony‐forming units/ml, and reductions from baseline were calculated.Results:  Compared with baseline, the TCF‐AF dentifrice reduced H2S‐forming bacteria 0.82, 0.80 and 0.22 log units at the 2 and 4 h and overnight time points compared with 0.60, 0.43 and 0.07 log units for the CBF dentifrice. The TCFAF dentifrice was statistically significantly better (P < 0.05) than the CBF dentifrice at 4 h and overnight after brushing the teeth.Conclusion:  The results of this randomized study indicate that the TCF‐AF dentifrice is effective in controlling H2S‐producing bacteria.
The analysis of characteristics of elderly people with high VSC level
Authors: Aizawa F , Kishi M , Moriya T , Takahashi M , Inaba D , Yonemitsu M 
Published: March 2005

Objective:  The purpose of this study was to examine the characteristics of elderly subjects who had objectionable levels of volatile sulfur compound (VSC).Subjects and method:  In 2002, a total of 115 85‐year‐old persons in Japan were subjected to oral examinations, tongue coat collections, measurements of VSCs levels inside the mouth using a portable gas chromatography (Oral ChromaTM, Abilit, Japan), and assessments of quality of life (QOL) using an SF‐36 questionnaire.Results:  Sixty‐six of the subjects were edentulous and 49 were dentulous. They were divided into two groups by VSC levels, those with oral malodor (both H2S > 112 ppb and CH3SH > 26 ppb; subjects with oral malodor, OM group; n = 7) and those without (n = 108). Our results showed that tongue coat deposit amounts and proportion of dentulous subjects were significantly higher in the OM group. Further, in an analysis of QOL, the SF‐36 scores for vitality, social functioning and mental health were significantly higher in OM.Conclusion:  We found that elderly subjects with oral malodor tended to be dentulous and had large deposits of tongue coating. However, oral malodor in the OM group subjects did not appear to cause a disadvantage in their social lives.
Halitosis and periodontal disease in subjects with mental disabilities
Authors: de Figueiredo LC , Feres M , Salvador SL 
Published: March 2005

Objective:  The aim of this study was to investigate the relationship between halitosis, presence of N‐benzoyl‐DL‐arginine‐2‐naphthylamide (BANA) positive activity (indicative of Treponema denticola, Porphyromonas gingivalis, Tannerella forsythensis) and periodontal conditions in subjects with mental disabilities.Materials and methods:  The population consisted of 17 Down syndrome (DS), 17 mentally retarded (MR) and 17 mentally healthy subjects (MH) – control group. A portable sulfide monitor was used to measure the concentration of volatile sulfur compounds (VSC) found in the mouth. Clinical parameters [Plaque Index (PlI), Probing Depth (PD), Bleeding on Probing (BOP)] were obtained from six reference teeth. Subgingival plaque samples for BANA Test were taken from the same six teeth and dorsum of the tongue.Results:  PlI and BOP were higher in DS than in MR and MH, respectively (P < 0.05). Mean PD was similar between DS and healthy groups but it was higher than the MR group. No significant differences were found among the three groups regarding the presence of BANA positive species, however the VSC levels were significantly lower in DS (97.23 ppb) than in MR (203.23 ppb) and MH individuals (180.53 ppb).Conclusions:  Even though the presence of BANA positive activity was similar among DS, MR and MH subjects, halitosis seemed to be lower in the DS group.
Subjective patients’ opinion and evaluation of halitosis using halimeter and organoleptic scores
Authors: Iwanicka‐Grzegorek E , Michalik J , Kepa J , Wierzbicka M , Aleksinski M , Pierzynowska E 
Published: March 2005

Objectives:  The aim of the study was to evaluate the level of interest in fetor ex ore among respondents, patients of the Department of Conservative Dentistry in Warsaw.Materials and Methods:  A questionnaire was completed by 295 patients, 202 females and 93 males aged 18–74 years (average 38.73 years). Each person was also examined for organoleptic score and volatile sulfur compounds (VSC) by Halimeter. Halitosis was diagnosed if the average level of VSC was ≥125 ppb and the organoleptic measurement using a 0–5 point scale was ≥2. Statistical analysis was performed using chi‐square test.Results:  Incidence of halitosis was greatest in age ranges 25–34 years (29.68%) and 45–54 years (24.52%). Sixty‐eight (43.87%) persons with diagnosed halitosis frequently reported having a problem with bad breath and only 5.81% persons with halitosis did not notice this problem (P < 0.001). Among 54 healthy persons three (5.56%) reported having a problem with halitosis (P < 0.001).Conclusion:  A statistically significant correlation was found between clinical organoleptic diagnosis of halitosis and VSC level by halimeter. Subjective patients’ opinion correlated well with objective evaluation of halitosis.
O22  Eating behaviour of institutionalized elderly people in relation to tongue cleaning
Authors: Neander KD , Seemann R , Rathke S , Hesse F 
Published: March 2005

Introduction  Backing the oral hygiene of elderly people in need of care is an important task for geriatric nursing personal. Tongue cleaning has been generally recommended to improve the oral hygiene status, to prevent the development of oral malodour, and to improve the sense of taste. In Germany, no official recommendations for oral hygiene procedures in hospitals or nursing homes are available and if tongue cleaning is performed a regular toothbrush or a wooden spatula are mainly used. So far, only limited data have been published regarding the influence of tongue cleaning on taste sensation.Aim  Therefore, the aim of this study was to investigate, whether a regime of daily tongue cleaning with a specially designed tongue cleaner could improve the eating behaviour of institutionalised elderly patients.Methods  The study population consisted of 150 edentulous occupants (mean age 74 ± 4 s.d.) of a nursing home in Goettingen. Each subject served as its own control. During the test phase of 2 weeks each participant received five times daily a tongue cleaning procedure using the One Drop Only tongue cleaner (One Drop Only, Berlin; Germany; a combination of a tongue brush and a tongue scraper). During the control run the tongue cleaning was carried out also five times daily over a 2‐week period using a regular toothbrush. All procedures were performed by a carefully instructed geriatric nurse. As a measure for the eating behaviour the amount of spurned and returned drinks and food was determined by weighing. The individual impression of taste was also determined by using a questionnaire. All subjects were able to eat and drink without assistance.Results  During the test period the subjects reported an increased appetite and only 18.3% of the served food and 17.1% of the served drinks were spurned and returned. In contrast, during the control phase the subjects returned 52% of the food and 53.2% of the drinks. These differences were statistically significant (P < 0.05, t‐test n. FERGUSON: α = 1%; f = 8; t = 3.37).Conclusion  From our data we can conclude that the daily use of a specially designed tongue cleaner (One Drop Only) was capable of improving the appetite of institutionalised elderly patients. (This study was carried out without knowledge and support of the One Drop Only Company).