bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Efficiency: The Practical Perspective
Authors: Kenett Ron S. , Coleman Shirley , Stewardson Dave 
Published: August 2003

AbstractThe idea of adding a practical perspective to the mathematical definition of statistical efficiency is based on a suggestion by Churchill Eisenhart who, years ago gave, in an informal ‘Beer and Statistics’ seminar, a new definition of statistical efficiency. Later Bruce Hoadley from Bell Laboratories picked up where Eisenhart left off and added his version nicknamed ‘Vador’. Blan Godfrey, former CEO of the Juran Institute, more or less used Hoadley's idea during his Youden Address at the Fall Technical Conference of the American Society for Quality Control. We expand on this idea adding an additional component, the value of the data actually collected, which we believe is critical to the overall idea. The concept of Practical Statistical Efficiency (PSE) derived from these developments is introduced and demonstrated using five case studies. We suggest that PSE be considered before, during and after undertaking any quality improvement projects. Copyright © 2003 John Wiley & Sons, Ltd.
Integration of Sequential Process Adjustment and Process Monitoring Techniques
Authors: Pan Rong , del Castillo Enrique 
Published: August 2003

AbstractDetecting abnormal disturbances and correcting them through adjustment are essential functions of quality control. This paper discusses a general sequential adjustment procedure based on stochastic approximation techniques and combines it with a control chart for detection. It is assumed that step‐like shifts of unknown size occur in the process mean at unknown points of time. The performance of the proposed methods depends on the sensitivity of the control chart to detect shifts in the process mean, on the accuracy of the initial estimate of the shift size, and on the number of sequential adjustments that are made. It is shown that sequential adjustments are superior to single adjustment strategies for almost all types of process shifts and magnitudes considered. A CUSUM (cumulative sum) chart used in conjunction with our sequential adjustment approach can improve the average squared deviations, the performance index considered herein, more than any other combined scheme unless the shift size is very large. The proposed integrated approach is compared with always applying a standard integral or exponentially weighted moving average controller with no monitoring component. Combining control charts and sequential adjustments is recommended for monitoring and adjusting a process when random shocks occur infrequently in time. Copyright © 2003 John Wiley & Sons, Ltd.
Control Charts for Monitoring Fault Signatures: Cuscore versus GLR
Authors: Runger George C. , Testik Murat C. 
Published: August 2003

AbstractIt is commonly assumed that an assignable cause may shift a process mean persistently to an unknown but constant value. However, there are situations such that a mean change is not persistently constant but time varying, which is known as the signature of a fault. Different forms of fault signatures may arise, especially when a residuals control chart is used to monitor an autocorrelated or closed‐loop controlled process. Incorporating a priori knowledge of a fault signature, fault‐sensitized control charts may be developed. In this paper, we investigate two control charts of this kind: generalized likelihood ratio (GLR) and cumulative score (Cuscore) charts. A sine wave representing a bounded signal and a linear trend representing an unbounded signal are used as fault signatures for investigation purposes. Two different cases are analyzed, a known fault signature and parameter and a known fault signature but unknown parameter. Both the initial performances and steady‐state performances of these charts are analyzed. The former case is somewhat artificial since it is synchronizing the control statistic and the fault signature; the latter one is more realistic since time of the occurrence of a fault is unknown. Simulation results show that GLR charts are robust to unknown signal start times and perform better than the alternatives for the cases compared. Copyright © 2003 John Wiley & Sons, Ltd.
Effects of mechanical tension on matrix degradation by human periodontal ligament cells cultured in collagen gels
Authors: Von den Hoff J. W. 
Published: August 2003

Background:  Periodontal ligament (PDL) cells are thought to play a crucial role in the remodelling of periodontal tissues during orthodontic tooth movement.Objective:  The objective of this study was to analyse the effects of mechanical tension on matrix degradation by PDL cells cultured in collagen gels.Methods:  The gels were prepared free‐floating or attached to the culture wells and cultured for up to 22 d. In free‐floating gels very little mechanical tension is generated within the matrix, whereas in attached gels tension is highly increased.Results:  At d 8, free‐floating gels had contracted to 2% of their original wet weight. Attached gels had contracted to only 40%, but by d 15 all gels had spontaneously detached from the wells and had contracted rapidly. The collagen content of free‐floating gels had decreased to 30% of the initial value at d 22. Collagenase activity was detected in the culture media of the free‐floating gels and the presence of matrix metalloproteinases (MMPs) 2 and 9 was shown by zymography. In addition, histological sections showed matrix degradation around the cells. This shows that ligament cells in free‐floating gels are actively resorbing the collagen matrix. The collagen content of attached gels did not change during the first 8 d but, after detachment, it rapidly decreased to 2%. Therefore, mechanical tension seems to prevent degradation of the matrix. In contrast, relaxation of the tension enhances the resorptive activity.Conclusions:  The sensitivity of PDL cells to mechanical tension may be essential for the remodelling of periodontal tissues and their adaptation to physiological and orthodontic forces.
A new method for evaluating the threshold of periodontal ligament mechanoreceptor by slow speed mechanical stimulation
Authors: Oki Kazuhiro , Hamanaka Mai , Arima Taro , Takahashi Shuhei , Hasegawa Kouichi , Minagi Shogo 
Published: August 2003

Objectives:  This study aimed to establish a reliable method for detecting the threshold for perception of force applied to tooth and to report the basic properties of force threshold in the normal dentition subjects.Background:  The perception of mechanical stimulation exerted to tooth is formed by input from periodontal ligament mechanoreceptors and intradental mechanoreceptors. Periodontal ligament mechanoreceptors respond to a wide range speed of stimulus, whereas intradental mechanoreceptors are activated only by a rapid stimulation. Reliable properties of perception have not been reported because of the difficulties to regulate velocity and degree of the stimulus.Methods:  Eighteen healthy subjects were observed in this study (mean age: 27.2 ± 5.7 years). A loading device to generate slow speed loading was fabricated and measured as follows: (i) the fluctuation of the force threshold within a day, (ii) day‐to‐day fluctuation, (iii) changes in the force threshold by a transient mechanical loading.Results:  In the normal dentition, it was observed that the fluctuation within a day and day to day of the pressure sense showed no significant differences; however, a transient mechanical loading caused the sensitivity of the periodontal ligament to decrease significantly.Conclusions:  The device examining the force threshold resulted from periodontal ligament mechanoreceptors was useful in evaluating the sensitivity of the periodontal ligament.
Identification of mRNAs for the various diacylglycerol kinase isoforms in neutrophils from patients with localized aggressive periodontitis
Authors: Oyaizu Kosuke , Kantarci Alpdogan , Maeda Hiroshi , L. Batista Eraldo , Hasturk Hatice , Murayama Yoji , Badwey John A. , Van Dyke Thomas E. 
Published: August 2003

Background:  Diacylglycerol kinase (DGK) metabolizes diacylglycerol (DAG), an endogenous activator of protein kinase C, to phosphatidic acid. We have previously reported increased DAG in neutrophils from patients with localized aggressive periodontitis (LAP) associated with reduced DGK activity. This reduction could be related to a mutation, post‐translational modification, differential expression, or lack of expression of a particular isoform(s).Objective:  The aim of this study was to identify the mRNAs for DGK isoforms in normal and LAP neutrophils.Methods:  The α‐, γ‐, and δ‐isoforms of DGK were identified by polymerase chain reaction (PCR) using specific oligonucleotide primers for each isoform. The PCR products were isolated and sequenced for comparison to published sequences to confirm the validity of the PCR reaction. Total RNA was isolated from LAP and normal neutrophils, and northern blotting and semi‐quantitative reverse transcription polymerase chain reaction (RT‐PCR) was used to examine the level of mRNA for each isoform.Results:  No major differences were found in the isoform pattern between resting normal and LAP neutrophils. However, the levels of mRNA for the α‐ and γ‐isoforms of DGK were increased in normal neutrophils while slightly decreased in LAP cells upon stimulation with N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP).Conclusion:  These data suggest that alterations in the mRNAs for the various isoforms of DGK during cell stimulation and the involvement of DGK that is expressed in multiple forms are subject to a variety of regulatory/control mechanisms and these mechanisms may explain the role of the ‘primed’ neutrophil phenotype associated with LAP.
Are there HLA combinations typical supporting for or making resistant against aggressive and/or chronic periodontitis?
Authors: Stein J. , Reichert S. , Gautsch A. , Machulla H. K. G. 
Published: August 2003

Objective and background:
Human leukocyte antigens (HLA)/alleles have been considered as risk factors for periodontal disease. However, data from HLA associations is not consistent. Diversity of HLA antigen combinations and en bloc inherited HLA alleles (haplotypes), as known in systemic diseases, can be variable factors in disease association. Therefore, the aim of this study was to investigate the incidence of HLA homozygosities, heterozygosities and estimated haplotypes in German Caucasian groups with generalized aggressive (N = 50) and chronic (N = 102) periodontitis in comparison to control probands without periodontitis (N = 102).Methods:  HLA‐A, ‐B, ‐Cw, ‐DRB1, ‐DRB3/4/5, ‐DQB1 typing was carried out using both serologic (microlymphocytotoxicity test) and genomic (PCR‐SSP: PCR with sequence specific primers) techniques. Frequencies of all homozygosities, heterozygosities and haplotypes were determined in all patients and controls.Results:  In both patient groups, associations to HLA homozygosities and heterozygosities were found. Most striking was the significantly lower frequency of HLA‐DRBblank* homozygosity (non‐DRB3*/DRB4*/DRB5*) in chronic periodontitis (p < 0.05), whereas HLA‐DRB1*15 : DRB5*(DR51) : DQB1*06 showed a slightly higher homozygosity rate in all patients. As the combination HLA‐A*02,A*03 was significantly decreased in aggressive periodontitis (p < 0.05), HLA‐A*01,A*03 heterozygosity was significantly lowered in chronic periodontitis (p < 0.05). Among others, the known positive associations for HLA‐A*68/69 (A28) and HLA‐DRB1*04 were confirmed by the haplotypes HLA‐A*68/69 : Cw*07 : B*18 in aggressive periodontitis (p < 0.05) and HLA‐Cw*08 : B*14 : DRB1*04 in chronic periodontitis (p < 0.05).Conclusion:  The present study elucidates the variety of HLA associations and therefore the difficulty to assign single HLA markers to periodontal disease. Susceptibility/resistance of both aggressive and chronic periodontitis may rather be influenced by particular HLA marker combinations. Associated HLA haplotypes may be of further importance for unknown gene loci representing a part of the genetic background for periodontitis. The different associations in aggressive and chronic periodontitis indicate different susceptibility/resistance factors for both diseases.
Quantitative real‐time PCR based on single copy gene sequence for detection of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis
Authors: Morillo Juan M , Lau Laura , Sanz Mariano , Herrera David , Silva Augusto 
Published: August 2003

Objective:  To establish a method for quantification of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis from subgingival plaque by real‐time polymerase chain reaction (PCR) technique.Material and methods:  Bacterial cells from both species were obtained from type culture and counted microscopically. Cellular suspension in sterile destilled water was used for DNA extraction by boiling for 20 min, with a mineral oil cover. Primers for PCR were selected from sequences of LktC gene (A. actinomycetemcomitans) and Arg‐gingipain (P. gingivalis) to yield amplicons below 100 bp. SYBR Green I based real‐time PCR was adjusted to quantify separately both species.Results:  A good sensitivity and specificity were obtained for both species, although the yield was better for A. actinomycetemcomitans. A good repeatibility of cycle threshold (CT) was encountered, so coefficient of variation was below 6% at every initial copy number.Conclusion:  A new method of quantification of A. actinomycetemcomitans and P. gingivalis based on SYBR Green real‐time PCR is presented. Its good sensibility and repeatibility will allow its application to analysis of subgingival plaque samples.
Dental root resorption and repair: histology and histometry during physiological drift of rat molars
Authors: Kimura Ryusei , Anan Hisashi , Matsumoto Akiko , Noda Daisuke , Maeda Katsumasa 
Published: August 2003

Objective:  The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model.Methods:  Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate‐resistant acid phosphatase (TRAP) reaction.Results:  Root resorption was observed in the distal side of the roots and was most active in 5‐ to 6‐week‐old rats, and gradually decreased hereafter. An increase in the number of TRAP‐positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active.Conclusions:  The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces.
Effects of autoclave sterilization on properties of dental rubber dam as related to its use as barrier membrane in guided tissue regeneration
Authors: Apinhasmit Wandee , Limsombutanon Somchai , Swasdison Somporn , Suppipat Nophadol 
Published: August 2003

Background and Objective:  Dental rubber dams (RDs) were used as barrier membranes in guided tissue regeneration for the treatment of periodontal intraosseous defects with acceptable clinical results. The aim of the present study was to investigate the effects of autoclave sterilization on properties of RD as related to its use as a barrier membrane in guided tissue regeneration.Methods:  RDs were sterilized by either an autoclave, gamma irradiation, or chemical agents and then co‐cultured with human gingival fibroblasts. The cell responses to sterilized RDs were investigated by inverted phase contrast microscopy, scanning electron microscopy (SEM) and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) technique. The surface alterations of the autoclaved RDs were observed under SEM. The tensile strength, tear strength and elongation at break of the autoclaved RDs were tested by a universal testing machine.Results:  The results from cell culture, microscopic and MTT studies showed that RDs sterilized by autoclave and gamma irradiation did not deteriorate gingival fibroblasts and provided surfaces suitable for cell attachment, whereas chemical‐sterilized RDs were toxic to these cells. Ultrastructurally, surface changes from the non‐autoclaved RDs, including some melted areas, small pores and folds were observed on the autoclaved RD surface. The tensile strength and tear strength of the autoclaved RDs were significantly lower than those of the non‐autoclaved RDs (p = 0.042, p < 0.001, respectively). In contrast, the elongation at break of the autoclaved RDs was higher than that of the non‐autoclaved RDs (p < 0.001).Conclusion:  These results suggest that the autoclave sterilization deteriorated the physical properties of RDs even though they seemed to be compatible to the cultured human cells. Therefore, the sterilization method should be taken into consideration when RDs are utilized as barrier membranes.
Role of snus (oral moist snuff ) in smoking cessation and smoking reduction in Sweden
Authors: Gilljam Hans , Galanti M. Rosaria 
Published: August 2003

ABSTRACTAims  To assess to what extent snus has been used as an aid to stop smoking among Swedish smokers.Design  A random telephone retrospective survey of Swedish smokers and ex‐smokers.Setting  Survey conducted in November–December 2000.Participants  A national sample of 1000 former and 985 current daily smokers aged 25–55 years.Measurements  Smoking status, date and method of quitting by self‐report.Findings  Thirty‐three per cent of former smokers and 27% of current smokers had ever used snus. The difference was larger among men (55% versus 45%, P = 0.003). Current smokers who made use of snus smoked on average fewer cigarettes per day than non‐users of snus. The mean duration of abstinence among former smokers was not influenced by snus use. Conditionally on age, education and use of nicotine replacement therapy there was an increased probability of being a former rather than a current smoker with ever use (OR 1.72, 95% CI = 1.30–2.28) or current use (OR 1.81, 95% CI = 1.31–2.53) of snus. Having used snus at the latest quit attempt increased the probability of being abstinent by about 50% (OR 1.54, 95% CI = 1.09–2.20).Conclusions  Our study suggests that by using snus, Swedish male smokers may increase their overall chances of abstinence. However, 71% of the men in this sample who quit smoking did so without using snus and the duration of abstinence was not affected by snus use. This suggests that snus is not a necessary component of smoking cessation at the population level. Snus use was very rare among women.
Should the European Union lift the ban on snus? Evidence from the Swedish experience
Authors: Fagerström Karl Olov , Schildt Elsy‐Britt 
Published: August 2003

ABSTRACTThe very low smoking prevalence in Sweden has received considerable attention. Sweden was the only country in Europe to reach the World Health Organizations’ goal of less than 20% daily smoking prevalence among adults by year 2000. Only 17% of Swedish men smoke. Some have argued that this has been achieved because Swedes use another form of tobacco instead. Sweden has a high level of use of a moist snuff product called ‘snus’. Nineteen per cent of adult men and 1% of women are daily users and the trend is increasing. Epidemiological studies have failed to find evidence that snus causes cancers, including oral cancer. Its adverse effects on the cardiovascular system are debated, but are certainly less than those of smoking. Recent studies among former smokers indicate that many men have quit smoking using snus. Forty‐seven per cent of current snus users are former smokers and 28% of ex‐smoking used snus at their last attempt to stop smoking. The association between high snus consumption and low smoking prevalence has been debated and challenged. It has been argued that snus may be a gateway to cigarette smoking. Recent data has found that among those starting tobacco use in the form of snus, 20% later go on to smoking while the same risk for those not starting with snus is 43%. On balance, there is reason to believe that having snus available to the Swedish population has been of benefit to public health. Repealing the ban on snus in the rest of the European Union might also have some positive effect, depending on the marketing.
Improving self‐reports of drug‐use: numeric estimates as fuzzy sets
Authors: Matt Georg E. , Turingan Maria R. , Dinh Quyen T. , Felsch Julie A. , Hovell Melbourne F. , Gehrman Christine 
Published: August 2003

ABSTRACTAims  This study compared traditional crisp set to fuzzy set representations of quantitative estimates of drug use to investigate what survey respondents recall about their drug use.Design  Sample survey comparing (a) responses to traditional survey questions asking for single numeric estimates to (b) responses to fuzzy set questions asking for boundary estimates of drug use.Setting  Research facilities of a public university in a large southern California city.Participants  Community residents using tobacco, alcohol, marijuana or amphetamine (n = 88).Measurements  Personal interviews in which participants reported onset, frequency and daily rate of tobacco, alcohol, marijuana and amphetamine use based on traditional survey questions and fuzzy set questions.Findings  With the exception of marijuana use, fuzzy boundary estimates differed significantly from the traditional point estimates (P < 0.05). Median retest reliabilities for fuzzy boundary estimates were 0.96 (tobacco), 0.81 (alcohol), 0.96 (marijuana) and 0.95 (amphetamine). The degree of vagueness varied by behavior and drug, with estimates of daily rates showing greatest fuzziness and onset of use showing least fuzziness.Conclusions  Participants recall more about past drug use than a single numeric estimate. All numeric estimates of drug use showed fuzzy set properties. Compared to traditional self‐reports of drug use, fuzzy set representations provide a more complete and detailed description of what participants recall about past drug use.