bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient Root Resorption after Dental Trauma: The Clinician's Dilemma
Authors: ANDREASEN FRANCES M.
Published: October 2006

The diagnostic shortcomings encountered in the clinical evaluation of pulpal and periodontal healing subsequent to trauma comprise a major problem in dental traumatology. An acute dental trauma may imply impact to the hard dental tissues and damage to the pulp and periodontium (including surrounding alveolar bone). In the case of luxation injuries, the trauma often results in rupture of the neurovascular supply at the level of the apical foramen, whereas in a root fracture, the same occurs at the level of the fracture. Conventional diagnostic criteria for pulpal status (coronal discoloration, loss of pulpal sensibility, tenderness to percussion, and radiographic change [i.e., resorption]) reflect, only indirectly, certain parameters of healing. These parameters are based empirically on clinical findings after dental caries and dental restorative techniques, where the pulp has an intact neurovascular supply apically. In these situations, long‐standing bacterial or chemical attack can lead to irreversible change. In contrast, following traumatic impact, a presumably intact pulp is deprived of its neurovascular supply instantaneously. In the absence of infection, events following acute dental trauma aim at either tissue repair or regeneration. Thus, based on a series of long‐term clinical studies, it was found that all conventional signs, with the exception of tenderness to percussion, could be signs of pulpal healing, as well as signs of pulpal death. Based on the results of these studies, this report discusses the significance of radiographic change (resorption) in relation to pulpal and periodontal healing following acute trauma. Moreover, implications of tooth luxation with respect to the long‐term prognosis following crown, crown‐root, and root fractures are discussed.

CLINICAL SIGNIFICANCE

Whenever possible, it is to the patient's advantage that pulp vitality be preserved. Correct diagnostic techniques and patient selection enable the clinician to decide when endodontic therapy is appropriate and when intelligent observation is the “treatment” of choice.
Evaluation of “Golden Proportion” in Individuals with an Esthetic Smile
Authors: MAHSHID MINOO , KHOSHVAGHTI ALIREZA , VARSHOSAZ MASOUD , VALLAEI NASER
Published: October 2006

Background:

One of the most important tasks in esthetic dentistry is creating harmonious proportions between the widths of maxillary anterior teeth when restoring or replacing these teeth. The “golden proportion” is a main guideline introduced in this field.

Purpose::

This study aimed to investigate the existence of the golden proportion between the widths of the maxillary anterior teeth in individuals with an esthetic smile.

Materials and Methods:

This study was conducted with 157 dental students (75 women and 82 men), with ages ranging from 18 to 30 years. Students whose natural smile did not develop any visual tension (see below) with regard to the study's and their own criteria were selected as having esthetic smile. An image measurement program was used to measure the apparent mesiodistal widths of six maxillary anterior teeth on the scanned photographs of these subjects. The existence of the golden proportion was investigated in the width ratios of maxillary anterior teeth.

Results:

The golden proportion was not found to exist between perceived maxillary anterior teeth widths of individuals with an esthetic smile.

Conclusion:

The golden proportion is not a common factor in esthetic smiles.
Temporary Crowns: Repositioning Key as a New Technical Approach in the Clinical Relining Phase
Authors: SIMEONE PIERO , MD ANDREA PILLONI.
Published: October 2006

To accomplish prosthetic rehabilitation, a series of important procedures must be followed to achieve the correct final prosthetic outcome. The protocol presented in this article proposes a different approach that involves relining the temporary crowns during the provisional phase by means of a repositioning key. This approach is especially useful for therapeutic provisional restoration in patients with temporomandibular joint disorders.
RESIN BOND TO DENTAL CERAMICS, PART II: HIGH‐STRENGTH CERAMICS
Authors: Blatz Markus B. , Richter Courtney , Sadan Avishai , Chiche Gerard J. , Swift Edward J.
Published: October 2006

The popularity of high‐strength ceramic systems is increasing, and the range of their clinical indications is expanding constantly. Glass‐infiltrated aluminum oxide ceramic (eg, InCeram® Alumina, Vita Zahnfabrik, Bad Säckingen, Germany), densely sintered aluminum oxide ceramic (eg, Procera® AllCeram, Nobel Biocare AB, Gothenburg, Sweden), and zirconium oxide ceramic (eg, Procera AllZirkon®, Lava® 3M ESPE, St. Paul, MN, USA, Cercon®, Dentsply Ceramco, Burlington, NJ, USA) are popular oxide‐based high‐strength ceramic materials that offer favorable esthetic characteristics, mechanical properties, and biocompatibility. Proper selection and application of luting agents for final cementation of all‐ceramic restorations are keys for their clinical success. The few clinical trials on full‐coverage, high‐strength ceramic restorations report acceptable success rates with conventional luting agents. However, an article discussed in Part I of this Critical Appraisal reviewed available in vitro and in vivo studies on this topic and recommended adhesive cementation of ceramic and even high‐strength ceramic restorations. These findings contradict many manufacturers’claims and clinicians’preferences because resin bonding is a technique‐sensitive and time‐consuming procedure. However, resin bonding has a number of advantages (eg, increased retention, improved marginal adaptation, and higher fracture resistance of the restored tooth and the restoration itself) and is required for some minimally invasive treatment options, such as resin‐bonded fixed partial dentures and laminate veneers.

The resin bond to silica‐based ceramics is well documented (as discussed in Part I of this Critical Appraisal) and yields predictable and long‐term durable results through adequate surface preparation. Part II focuses on in vitro studies of the bonding interface of some popular high‐strength ceramic materials. Comparative clinical trials are lacking, and the few available in vitro studies indicate that the composition and physical properties of oxide‐based high‐strength ceramics require surface preparation and bonding techniques that differ substantially from those used for silica‐based ceramics.
Dentinal Bonding Reaches the Root Canal System
Authors: TEIXEIRA FABRICIO B. , TEIXEIRA ERICA C.N. , THOMPSON JEFFREY , LEINFELDER KARL F. , TROPE MARTIN
Published: October 2006

Several factors can contribute to the achievement of success with endodontic therapy. After an effective microbial‐control phase, an adequate canal and coronal filling will guarantee a high probability of success. Gutta‐percha has for many years been widely used as a solid material in root fillings associated with different types of sealers. Even associated with a sealer, this material it is not capable of preventing leakage, as has been shown in many studies. In fact, because of gutta‐percha's limitations, the seal of a coronal restoration may be as important as the guttapercha fill in preventing reinfection of the root canal. Although sealers can form close adhesion to the root canal wall, none is able to bond to the gutta‐percha core material. Upon setting, the sealer pulls away from the gutta‐percha core, leaving a gap through which bacteria may pass. This article describes a new thermoplastic, synthetic root canal filling material, whose design is based on polyester chemistry, that looks and handles like gutta‐percha. It is used in the same manner as most bonding systems. After the usual preparation of the root canal, a self‐etch primer is used to condition the canal walls and prepare them for bonding to the resin. The resin sealant is introduced in the root canal. It bonds to the primer and to the resin core material; thus, a “monoblock” is formed without the gaps typical in gutta‐percha fillings. Studies have shown that leakage of bacteria with this material is significantly reduced compared with gutta‐percha.
Comparison of Effectiveness of Two 10% Carbamide Peroxide Tooth‐Bleaching Systems Using Spectrophotometric Measurements
Authors: ISHIKAWA‐NAGAI SHIGEMI , TERUI TAKAYUKI , ISHIBASHI KANJI , WEBER HANS PETER , FERGUSON MICHAEL
Published: October 2006

Purpose::

The purpose of this study was to compare the color changes achieved with two commonly used bleaching systems on the basis of a spectrophotometric analysis.

Materials and Methods:

Two commercially available 10% carbamide peroxide bleaching systems were used by a total of 48 individuals. Subjects who had intact natural maxillary anterior teeth void of any restorations or decay that had not been subjected to any prior bleaching were included. Opalescence 10% PF (Ultradent Products Inc., South Jordan, UT, USA) was used by 23 patients for 14 days, whereas Nite White Excel (Discus Dental, Culver City, CA, USA) was applied by 25 patients for the same duration. Tooth colors for the middle one‐third region of maxillary central incisors and canines were measured with a spectrophotometer prior to bleaching and after 14 days of bleaching. Color difference DE and color coordinates L* (lightness), a* (redness), and b* (yellowness) of CIELAB color system (developed by the Commission Internationale de l'Eclairage) were calculated.

Results:

Mean DE values for Opalescence ranged from 5.03 to 8.92 and from 5.84 to 9.61 for Nite White. The most significant factor of the color change was b* followed by L* and a*. L* values were higher after bleaching, whereas values for both a* and b* decreased. There were no significant differences between the two systems examined (p < .05).
SAFETY OF DENTAL AMALGAM
Authors: Osborne John W. , Swift Edward J.
Published: October 2006

This Critical Appraisal is a departure from our usual format. Usually, contributors review several articles about a specific topic. Instead, we have asked Dr. Osborne to review several topics related to a specific issue, the safety of dental amalgam. Despite the increasing use of tooth‐colored restorative materials, amalgam remains a widely used and important part of the dentist's armamentarium. This article provides the practicing dentist with essential information regarding the safety of amalgam. We hope that you will find this helpful as you discuss safety issues with concerned patients.
Novel Porcelain Laminate Preparation Approach Driven by a Diagnostic Mock‐up
Authors: MAGNE PASCAL , BELSER URS C.
Published: October 2006

One critical step in the porcelain laminate technique is the achievement of sufficient ceramic thickness. At least two different strategies for tooth preparation can be found in the literature: (1) earlier simplified techniques included the use of depth cutters guided by the existing tooth surface–however, that approach did not take into consideration alterations of the tooth owing to aging, wear, or loss of enamel and thus led to greater risks for dentin exposures; (2) more recent and sophisticated methods have integrated an additive diagnostic procedure (ie, wax‐up or mock‐up) to compensate for tooth aging or severe existing loss of tooth substance. This approach allows for more enamel preservation and, as a consequence, more predictable bonding, biomechanics, and esthetics. The present article illustrates in detail the latest development in tooth preparation for porcelain laminates. This technique combines the time efficiency of earliest methods with the rationale and diagnostic foundations of the more recent techniques.
Direct Composite Resin Restorations: A Review of Some Clinical Procedures to Achieve Predictable Results in Posterior Teeth
Authors: LOPES GUILHERME CARPENA , VIEIRA LUIZ CLOVIS CARDOSO , ARAUJO ELITO
Published: October 2006

The interest of patients in having tooth‐colored restorations and the development of techniques and materials that make these restorations easier have contributed to make the esthetic restoration of posterior teeth popular. The direct use of composites in posterior teeth is a techniquesensitive procedure. Some difficulties, nevertheless, can be overcome or at least minimized by a heedful clinician by paying thorough attention to the various stages of the restorative technique. The present article seeks to review some concepts about this adhesive restorative procedure and to illustrate the possibilities of the technique with clinical reports.

CLINICAL SIGNIFICANCE

The direct posterior composite restorative technique offers the possibility of closely matching the natural optical characteristics of the lost tooth structure. Aimed at showing the potential of this technique, this article presents two step‐by‐step case reports and also reviews some concepts related to these clinical procedures.
Surface Roughness of Packable Composite Resins Polished with Various Systems
Authors: BORGES ALESSANDRA BOHLER , MARSILIO ANA LUCIA , PAGANI CLÓVIS , RODRIGUES JOSÉ ROBERTO
Published: October 2006

Purpose: The aim of this study was to evaluate the surface roughness of four packable composite resins, SureFilTM (Dentsply, Petrópolis, Rio de Janeiro, Brazil), Prodigy CondensableTM (Kerr Co., Orange, CA, USA), Filtek P60TM (3M do Brasil, São Paulo, Brazil), and ALERT® (Jeneric/Pentron, Inc., Wallingford, CT, USA) and one microhybrid composite resin (Filtek Z250TM, 3M do Brasil) after polishing with four finishing systems.

Materials and Methods: Twenty specimens were made of each material (5 mm in diameter and 4 mm high) and were analyzed with a profilometer (Perthometer® S8P, Perthen, Mahr, Germany) to measure the mean surface roughness (Ra). The specimens were then divided into four groups according to the polishing system: group 1–Sof‐LexTM (3M do Brasil), group 2–EnhanceTM (Dentsply), group 3–Composite Finishing Kit (KG Sorensen, Barueri, São Paulo, Brazil), and group 4–Jiffy Polisher Cups® (Ultradent Products, Inc., South Jordan, UT, USA). The specimens were polished and then evaluated for Ra, and the data were subjected to analysis of variance, analysis of covariance, and Tukey's test (p= .05).

Results: The mean Ra of SureFil polished with Sof‐Lex was significantly lower than that of KG points. Prodigy Condensable polished with Enhance showed a significantly less rough surface than when polished with Sof‐Lex. Filtek P60 did not exhibit a significant difference with the various polishing systems. For ALERT the lowest mean Ra was obtained with Sof‐Lex and the highest mean Ra with KG points. Regarding Filtek 2250, polishing with KG and Jiffy points resulted in a significantly lower mean Ra than when polished with Enhance.

Conclusions: Packable composite resins display variable roughness depending on the polishing system used; the Sof‐Lex disks and Jiffy points resulted in the best Ra values for the majority of the materials tested.
Desensitizing Agent Efficacy during Whitening in an At‐Risk Population
Authors: LEONARD RALPH H. , SMITH LYNN R. , GLENN E. GARLAND DDS  , CAPLAN DANIEL J.
Published: October 2006

Background: Nightguard vital bleaching (NGVB) has gained acceptance among dentists and patients as a simple and effective procedure to lighten discolored teeth. Although the efficacy and predictability of NGVB have been well established, it has been documented that patients undergoing the procedure may experience side effects such as tooth sensitivity (TS) and gingival irritation (GI). A previous NGVB study suggested that selected participants might benefit from a regimen of a desensitizing agent (DSA)to decrease or prevent TS during whitening.

Purpose: The purpose of this study was to determine whether the daily use of an active DSA (UltraEZTM, Ultradent Products Inc., South Jordan, UT, USA) during NGVB would decrease TS in a population at risk for TS when compared with a placebo.

Materials and Methods: Forty subjects participated in this single‐blind randomized clinical trial. All participants had indicated that they had preexisting TS or other risk factors for TS during NGVB. To evaluate TS caused by the tray alone, participants wore custom‐fitted maxillary whitening trays containing no DSA or whitening solution during week 1. Next, participants were randomly assigned to apply either the active DSA or placebo daily for 14 days in the trays for 30 minutes prior to whitening. The placebo was the same formulation as UltraEZ but without the desensitizing agents (3% potassium nitrate and 0.11% by weight fluoride ion). The bleaching solution was a 10% carbamide peroxide whitening solution (OpalescenceTM, Ultradent Inc.). Post treatment, participants were followed up for 1 week, during which time they used neither trays nor solutions. Throughout the study, participants completed a daily diary to record their perceptions of TS and the time spent wearing the tray with the whitening solution.

Results: Forty‐one percent of the active group had at least 1 day of TS during treatment compared with 78% of the placebo group. The difference was statistically significant (p= .027) using the two‐tailed Fisher exact test.
ENAMEL BONDING WITH SELF‐ETCH RESINS
Authors: Soonthornsawad Pacharee , Pereira Patricia N.R.
Published: October 2006

Resin adhesion has revolutionized restorative dentistry because it allows conservative preparations and bonding of various substrates to the tooth structure. Until recently all adhesive systems used an etching agent prior to the priming and bonding steps. Despite excellent clinical and laboratory test results for these three‐step systems, simplified adhesive systems were desired and consequently developed to reduce the number of steps during the bonding procedure. Currently there are essentially two philosophies of simplification: the total‐etch systems, with a separate etchant and a primer/adhesive; and the self‐etching systems, which combine etching and priming in one bottle and have a separate adhesive agent or which combine all three steps in a single solution and application. Unfortunately, despite simplification of bonding products, technique sensitivity, substrate variability, and concerns about enamel bonds have increased. This Critical Appraisal addresses a primary concern about self‐etching primers: enamel bonding.
EFFECT OF ADDITIONAL ENAMEL ETCHING AND A FLOWABLE COMPOSITE TO THE INTERFACIAL INTEGRITY OF CLASS II ADHESIVE COMPOSITE RESTORATIONS
Authors: Belli S. , Inokoshi S. , Özer F. , Pereira P.N.R. , Ogata M. , Tagami J.
Published: October 2006

Objective: The purpose of this study was to evaluate microleakage of Class II composite restorations using a self‐etching adhesive system with additional enamel etching and/or a flowable resin composite material.

Materials and Methods: Fifty standardized Class II cavities were prepared in the mesial and distal surfaces of extracted human third molars. All teeth were bonded with a self‐etching primer adhesive system (Clearfil® Liner Bond 2, Kuraray Co. Ltd., Osaka, Japan) according to the manufacturer's instructions and were restored with a resin composite (Clearfil® AP‐X, Kuraray Co. Ltd.). In the control group, only a self‐etching adhesive system was used. In the various experimental groups, the preparation surfaces were coated with a layer of flowable resin composite (Protect® Liner F, Kuraray Co. Ltd.) before the placement of resin composite, etched with 37% phosphoric acid (K‐Etchant®, Kkraray Co. Ltd.) before the application of the adhesive system, or treated with both of these options. In four groups of specimens, the preparation had a gingival margin in enamel. In a fifth group, the gingival margin was in dentin. All teeth were subjected to thermocycling, 300 cycles between 4°C and 60°C, and were sectioned in half through the restorations. Gaps or cracks at the resin‐tooth interfaces were observed directly using a laser scanning microscope and were recorded as percentages of the entire interface length.

Results: Separate enamel etching with phosphoric acid did not improve the resin‐enamel seal produced by the self‐etching primer alone. Flowable resin composite produced gap‐free resin‐dentin interfaces but could not prevent cracks and gap formation at the resin‐enamel interface.

Conclusions: Neither flowable resin composite nor enamel etching could prevent gap formation at enamel‐resin interfaces and crack formation in enamel walls when used with a self‐etching primer adhesive system. However, the flowable composite provided gap‐free resin‐dentin interfaces.
ULTRASONICALLY ASSISTED EXTRACTION OF PHENOLIC COMPOUNDS FROM AROMATIC PLANTS: COMPARISON WITH CONVENTIONAL EXTRACTION TECHNICS
Authors: PROESTOS CHARALAMPOS , KOMAITIS MICHAEL
Published: October 2006

Extracts of aromatic plants contain bioactive substances such as phenolic compounds, which could be used as natural antioxidants. Conventional, as well as ultrasonically assisted extractions (UAEs
) of phenolic compounds from aromatic plants using different solvents, have been studied. Reversed phase high performance liquid chromatography (RP‐HPLC
) with ultraviolet detection was employed for the analysis of phenolic compounds. Total phenolic compounds were determined by the Folin–Ciocalteu assay. The amount of extractable phenolic substances for this method decreased with decreasing polarity of the solvent in the order water, 60% methanol, 60% acetone, and ethyl acetate/water (60:30, v/v). The HPLC results indicate that UAE is a more effective technic compared to the conventional method but was dependent on the solvent and the temperature employed. Increasing the temperature of sonication, the efficiency of extraction of phenolic compounds for all solvents is enhanced. However, water extraction was found to give reduced amounts of phenolic compounds when compared with the conventional method.
The New International Health Regulations: An Historic Development for International Law and Public Health
Authors: Fidler David P. , Gostin Lawrence O.
Published: October 2006

The World Health Assembly (WHA) adopted the new International Health Regulations (IHR) on May 23, 2005. The new IHR represent the culmination of a decade-long revision process and an historic development for international law and public health. The new IHR appear at a moment when public health, security, and democracy have become intertwined, addressed at the highest levels of government. The United Nations (UN) Secretary-General Kofi Annan, for example, identified IHR revision as a priority for moving humanity toward “larger freedom.” This article analyzes the new IHR and their implications for global health and security in the 21st century.

The WHA instructed the WHO Director-General (DG) to revise the IHR in 1995 because the Regulations did not provide an effective framework for addressing the international spread of disease. Doubts about the IHR's effectiveness had, however, been present long before 1995. The critiques identified the narrow scope of the regulations (applying only to a small number of infectious diseases), the lack of compliance by states, and the absence of a strategy for responding to rapid changes in public health's global economic and technological environments.
Toward a “Wider and Juster Initiative”: Recent Comparative Work in Buddhist Ethics
Authors: Heim Maria
Published: October 2006

This essay considers some of the important trends in comparative approaches to Buddhist moral thinking, including early reflections on how and where to place Buddhist thought. It argues that some of the formative gestures shaping the field of Buddhist ethics sprang from contested efforts by historians of religion and philosophical formalists to chart a comparative methodology. The essay describes the methodological holism that characterizes important work in the field and argues against it, pointing instead to more diffuse lines of inquiry that do not efface Buddhism's historical diversity and the distinctiveness of its moral discourses. The essay begins to develop a different orientation in ethics that centers on the ethical study of human nature. To this end, it offers a small exercise in comparative moral psychology to explore the moral sentiment “sympathetic joy.”
Declaration of patent applications as financial interests: a survey of practice among authors of papers on molecular biology inNature
Authors: Mayer S
Published: October 2006

Objectives:To determine whether authors of scientific publications in molecular biology declare patents and other potential financial interests.

Design:Survey of a 6-month sample of papers related to molecular biology inNature.

Methods:The esp@cenet worldwide patent search engine was used to search for patents applied for by the authors of scientific papers inNaturethat were related to molecular biology and genetics, between January and June 2005.

Results:Of the 79 papers considered, four had declared that certain authors had competing financial interests. Seven papers in which no financial interests were declared had authors with patent applications that were based on the research in the paper or were closely related to it. Another paper had two authors with connections to biotechnology companies that were not disclosed.

Conclusion:Two thirds of the papers in which authors had patent applications or company affiliations that might be considered to be competing financial interests did not disclose them. Failure to disclose such information may have negative implications on the perception of science in society and on its quality if the possible bias is hidden. Journals should make greater efforts to ensure full disclosure, and scientific institutions should consider failure to disclose financial interests as an example of scientific malpractice. Establishing a register of interests for scientists is one way to increase transparency and openness.
Potentiality of embryonic stem cells: an ethical problem even with alternative stem cell sources
Authors: Denker H-W
Published: October 2006

The recent discussions about alternative sources of human embryonic stem cells (White Paper of the US President’s Council on Bioethics, 2005), while stirring new interest in the developmental potential of the various abnormal embryos or constructs proposed as such sources, also raise questions about the potential of the derived embryonic stem cells. The data on the developmental potential of embryonic stem cells that seem relevant for ethical considerations and aspects of patentability are discussed. Particular attention is paid to the meaning of “totipotency, omnipotency and pluripotency” as illustrated by a comparison of the developmental potential of three-dimensional clusters of blastomeres (morula), embryonic stem cells, somatic or (adult) stem cells or other somatic (non-stem) cells. This paper focuses on embryoid bodies and on direct cloning by tetraploid complementation. Usage and patenting of these cells cannot be considered to be ethically sound as long as totipotency and tetraploid complementability of embryonic stem cells are not excluded for the specific cell line in question. Testing this poses an ethical problem in itself and needs to be discussed in the future.
A case for justified non-voluntary active euthanasia: exploring the ethics of the Groningen Protocol
Authors: Manninen B A
Published: October 2006

One of the most recent controversies to arise in the field of bioethics concerns the ethics for the Groningen Protocol: the guidelines proposed by the Groningen Academic Hospital in The Netherlands, which would permit doctors to actively euthanise terminally ill infants who are suffering. The Groningen Protocol has been met with an intense amount of criticism, some even calling it a relapse into a Hitleresque style of eugenics, where people with disabilities are killed solely because of their handicaps. The purpose of this paper is threefold. First, the paper will attempt to disabuse readers of this erroneous understanding of the Groningen Protocol by showing how such a policy does not aim at making quality-of-life judgements, given that it restricts euthanasia to suffering and terminally ill infants. Second, the paper illustrates that what the Groningen Protocol proposes to do is both ethical and also the most humane alternative for these suffering and dying infants. Lastly, responses are given to some of the worries expressed by ethicists on the practice of any type of non-voluntary active euthanasia.
Therapeutic abortion in Islam: contemporary views of Muslim Shiite scholars and effect of recent Iranian legislation
Authors: Hedayat K M , Shooshtarizadeh P , Raza M
Published: October 2006

Abortion is forbidden under normal circumstances by nearly all the major world religions. Traditionally, abortion was not deemed permissible by Muslim scholars. Shiite scholars considered it forbidden after implantation of the fertilised ovum. However, Sunni scholars have held various opinions on the matter, but all agreed that after 4 months gestation abortion was not permitted. In addition, classical Islamic scholarship had only considered threats to maternal health as a reason for therapeutic abortion. Recently, scholars have begun to consider the effect of severe fetal deformities on the mother, the families and society. This has led some scholars to reconsider the prohibition on abortion in limited circumstances. This article reviews the Islamic basis for the prohibition of abortion and the reasons for its justification. Contemporary rulings from leading Shiite scholars and from the Sunni school of thought are presented and reviewed. The status of abortion in Muslim countries is reviewed, with special emphasis on the therapeutic abortion law passed by the Iranian Parliament in 2003. This law approved therapeutic abortion before 16 weeks of gestation under limited circumstances, including medical conditions related to fetal and maternal health. Recent measures in Iran provide an opportunity for the Muslim scholars in other countries to review their traditional stance on abortion.
Attitudes of Finnish doctors towards euthanasia in 1993 and 2003: Table 1
Authors: Louhiala P , Hilden H-M
Published: October 2006

Questionnaire studies on the attitudes of Finnish doctors towards euthanasia were conducted in 1993 and 2003, and the results show that they have not become more positive.
Hedgehog Morphogen in Cardiovascular Disease
Authors: Bijlsma Maarten F. , Peppelenbosch Maikel P. , Spek C. Arnold
Published: October 2006

In this review, we focus on the basic biology of the important developmental Hedgehog (Hh) protein family, its general function in development, pathway mechanisms, and gene discovery and nomenclature. Hh function in cardiovascular development and recent findings concerning Hh signaling in ischemia models are discussed in more detail, and future perspectives are proposed. In light of the recent discovery of Hh transport by insect lipophorin, we also hypothesize a role for low-density lipoprotein (LDL) in mammalian Hh transport, creating a surprising role for LDL in cardiovascular disease.
Multimodel Analysis of the Water Vapor Feedback in the Tropical Upper Troposphere
Authors: Minschwaner Ken , Dessler Andrew E. , Sawaengphokhai Parnchai
Published: October 2006

Relationships between the mean humidity in the tropical upper troposphere and tropical sea surface temperatures in 17 coupled ocean–atmosphere global climate models were investigated. This analysis builds on a prior study of humidity and surface temperature measurements that suggested an overall positive climate feedback by water vapor in the tropical upper troposphere whereby the mean specific humidity increases with warmer sea surface temperature (SST). The model results for present-day simulations show a large range in mean humidity, mean air temperature, and mean SST, but they consistently show increases in upper-tropospheric specific humidity with warmer SST. The model average increase in water vapor at 250 mb with convective mean SST is 44 ppmv K−1, with a standard deviation of 14 ppmv K−1. Furthermore, the implied feedback in the models is not as strong as would be the case if relative humidity remained constant in the upper troposphere. The model mean decrease in relative humidity is −2.3% ± 1.0% K−1 at 250 mb, whereas observations indicate decreases of −4.8% ± 1.7% K−1 near 215 mb. These two values agree within the respective ranges of uncertainty, indicating that current global climate models are simulating the observed behavior of water vapor in the tropical upper troposphere with reasonable accuracy.
Future Projections of Landfast Ice Thickness and Duration in the Canadian Arctic
Authors: Dumas J. A. , Flato G. M. , Brown R. D.
Published: October 2006

Projections of future landfast ice thickness and duration were generated for nine sites in the Canadian Arctic and one site on the Labrador coast with a simple downscaling technique that used a one-dimensional sea ice model driven by observationally based forcing and superimposed projected future climate change from the Canadian Centre for Climate Modelling and Analysis global climate model (CGCM2). For the Canadian Arctic sites the downscaling approach indicated a decrease in maximum ice thickness of 30 and 50 cm and a reduction in ice cover duration of 1 and 2 months by 2041–60 and 2081–2100, respectively. In contrast, there is a slight increase in simulated landfast ice thickness and duration at Cartwright in the future due to its sensitivity to snow–ice formation with increased snowfall and to a projected slight cooling over this site (along the Labrador coast) by CGCM2. The magnitude of simulated changes in freeze-up and break-up date was largest for freeze up (e.g., 52 days later at Alert by 2081–2100), and freeze-up date changes exhibited much greater regional variability than break up, which was simulated to be 30 days earlier by 2081–2100 over the Canadian Arctic sites.
Toward a Unified View of the American Monsoon Systems
Authors: Vera C. , Higgins W. , Amador J. , Ambrizzi T. , Garreaud R. , Gochis D. , Gutzler D. , Lettenmaier D. , Marengo J. , Mechoso C. R. , Nogues-Paegle J. , Dias P. L. Silva , Zhang C.
Published: October 2006

An important goal of the Climate Variability and Predictability (CLIVAR) research on the American monsoon systems is to determine the sources and limits of predictability of warm season precipitation, with emphasis on weekly to interannual time scales. This paper reviews recent progress in the understanding of the American monsoon systems and identifies some of the future challenges that remain to improve warm season climate prediction. Much of the recent progress is derived from complementary international programs in North and South America, namely, the North American Monsoon Experiment (NAME) and the Monsoon Experiment South America (MESA), with the following common objectives: 1) to understand the key components of the American monsoon systems and their variability, 2) to determine the role of these systems in the global water cycle, 3) to improve observational datasets, and 4) to improve simulation and monthly-to-seasonal prediction of the monsoons and regional water resources. Among the recent observational advances highlighted in this paper are new insights into moisture transport processes, description of the structure and variability of the South American low-level jet, and resolution of the diurnal cycle of precipitation in the core monsoon regions. NAME and MESA are also driving major efforts in model development and hydrologic applications. Incorporated into the postfield phases of these projects are assessments of atmosphere–land surface interactions and model-based climate predictability experiments. As CLIVAR research on American monsoon systems evolves, a unified view of the climatic processes modulating continental warm season precipitation is beginning to emerge.
Monitoring and Prediction of the Earth’s Climate: A Future Perspective
Authors: Trenberth Kevin E. , Moore Berrien , Karl Thomas R. , Nobre Carlos
Published: October 2006

The climate is changing because of human activities and will continue to do so regardless of any mitigation actions. Available climate observations and information are also changing as technological advances take place. Accordingly, an overview is given of a much-needed potential climate information system that embraces a comprehensive observing system to observe and track changes and the forcings of the system as they occur, and that develops the ability to relate one to the other and understand changes and their origins. Observations need to be taken in ways that satisfy the climate monitoring principles and ensure long-term continuity, and that have the ability to discern small but persistent signals. Some benchmark observations are proposed to anchor space-based observations and trends, including a much-needed step forward in the quality of water vapor observations. Satellite observations must be calibrated and validated, with orbital decay and drift effects fully dealt with if possible, and adequate overlap to ensure continuity. The health of the monitoring system must be tracked and resources identified to address issues. Fields must be analyzed into global products and delivered to users while stakeholder needs are fully considered. Data should be appropriately archived with full and open access, along with metadata that fully describe the observing system status and environment in which it operates. Reanalysis of the records must be institutionalized along with continual assessment of impacts of new observing and analysis systems. Some products will be used to validate and improve models, as well as initialize models and predict future evolution on multiple time scales using ensembles. Attribution of changes to causes is essential, and it is vital to fully assess past changes and model performance and results in making predictions to help appraise reliability and assess impacts regionally on the environment, human activities, and sectors of the economy. In particular, a revolution in the way developing countries use and apply climate information is expected. Such a system will be invaluable and further provides a framework for setting priorities of new observations and related activities. Without the end-to-end process the investments will not deliver adequate return and our understanding will be much less than it would be otherwise.
Climate Variability, Fish, and Fisheries
Authors: Lehodey P. , Alheit J. , Barange M. , Baumgartner T. , Beaugrand G. , Drinkwater K. , Fromentin J.-M. , Hare S. R. , Ottersen G. , Perry R. I. , Roy C. , van der Lingen C. D. , Werner F.
Published: October 2006

Fish population variability and fisheries activities are closely linked to weather and climate dynamics. While weather at sea directly affects fishing, environmental variability determines the distribution, migration, and abundance of fish. Fishery science grew up during the last century by integrating knowledge from oceanography, fish biology, marine ecology, and fish population dynamics, largely focused on the great Northern Hemisphere fisheries. During this period, understanding and explaining interannual fish recruitment variability became a major focus for fisheries oceanographers. Yet, the close link between climate and fisheries is best illustrated by the effect of “unexpected” events—that is, nonseasonal, and sometimes catastrophic—on fish exploitation, such as those associated with the El Niño–Southern Oscillation (ENSO). The observation that fish populations fluctuate at decadal time scales and show patterns of synchrony while being geographically separated drew attention to oceanographic processes driven by low-frequency signals, as reflected by indices tracking large-scale climate patterns such as the Pacific decadal oscillation (PDO) and the North Atlantic Oscillation (NAO). This low-frequency variability was first observed in catch fluctuations of small pelagic fish (anchovies and sardines), but similar effects soon emerged for larger fish such as salmon, various groundfish species, and some tuna species. Today, the availability of long time series of observations combined with major scientific advances in sampling and modeling the oceans’ ecosystems allows fisheries science to investigate processes generating variability in abundance, distribution, and dynamics of fish species at daily, decadal, and even centennial scales. These studies are central to the research program of Global Ocean Ecosystems Dynamics (GLOBEC). This review presents examples of relationships between climate variability and fisheries at these different time scales for species covering various marine ecosystems ranging from equatorial to subarctic regions. Some of the known mechanisms linking climate variability and exploited fish populations are described, as well as some leading hypotheses, and their implications for their management and for the modeling of their dynamics. It is concluded with recommendations for collaborative work between climatologists, oceanographers, and fisheries scientists to resolve some of the outstanding problems in the development of sustainable fisheries.
Local Coupled Equatorial Variability versus Remote ENSO Forcing in an Intermediate Coupled Model of the Tropical Atlantic
Authors: Illig Serena , Dewitte Boris
Published: October 2006

The relative roles played by the remote El Niño–Southern Oscillation (ENSO) forcing and the local air–sea interactions in the tropical Atlantic are investigated using an intermediate coupled model (ICM) of the tropical Atlantic. The oceanic component of the ICM consists of a six-baroclinic mode ocean model and a simple mixed layer model that has been validated from observations. The atmospheric component is a global atmospheric general circulation model developed at the University of California, Los Angeles (UCLA). In a forced context, the ICM realistically simulates both the sea surface temperature anomaly (SSTA) variability in the equatorial band, and the relaxation of the Atlantic northeast trade winds and the intensification of the equatorial westerlies in boreal spring that usually follows an El Niño event.

The results of coupled experiments with or without Pacific ENSO forcing and with or without explicit air–sea interactions in the equatorial Atlantic indicate that the background energy in the equatorial Atlantic is provided by ENSO. However, the time scale of the variability and the magnitude of some peculiar events cannot be explained solely by ENSO remote forcing. It is demonstrated that the peak of SSTA variability in the 1–3-yr band as observed in the equatorial Atlantic is due to the local air–sea interactions and is not a linear response to ENSO. Seasonal phase locking in boreal summer is also the result of the local coupling. The analysis of the intrinsic sustainable modes indicates that the Atlantic El Niño is qualitatively a noise-driven stable system. Such a system can produce coherent interdecadal variability that is not forced by the Pacific or extraequatorial variability. It is shown that when a simple slab mixed layer model is embedded into the system to simulate the northern tropical Atlantic (NTA) SST variability, the warming over NTA following El Niño events have characteristics (location and peak phase) that depend on air–sea interaction in the equatorial Atlantic. In the model, the interaction between the equatorial mode and NTA can produce a dipolelike structure of the SSTA variability that evolves at a decadal time scale. The results herein illustrate the complexity of the tropical Atlantic ocean–atmosphere system, whose predictability jointly depends on ENSO and the connections between the Atlantic modes of variability.
Robust Optimum Designs of Fiber-reinforced Composites Using Constraints with Sensitivity
Authors: Liao Yunn-Shiuan , Chiou Chwei-Yuh
Published: October 2006

An efficient method of optimization considering manufacturing uncertainties is proposed in this article. By including the sensitivities and uncertainties in the modified constraints, a robust optimum design problem is formulated, which analytically deals with the effects of manufacturing uncertainties by a maximizing procedure. Although the maximizing procedure utilizes the similar concept of anti-optimization technique, and a numerical method is still needed for the optimization sub-problem, the anti-optimization sub-problem is analytically, rather than numerically, solved in the proposed method. It is therefore more efficient in computing time than traditional anti-optimization technique where both optimization and anti-optimization sub-problems are solved numerically. The proposed method is used for the robust optimum design of fiber-reinforced composites, which have wide scatters of stiffness, stress, and factor of safety due to the inherent manufacturing uncertainties of ply-thickness and ply-orientation. The accuracy of the new method for robust optimum design is demonstrated by verifying examples with analytical solution. The effects of ply orientation and ply thickness uncertainties on optimum weight of composite plate are studied in the illustrated examples. It is found that the optimum weight increases with ply orientation and ply thickness uncertainties, and uncertainties have strong effect on the optimal weight in all analysis cases.
A Time-domain Reflectometry Method for Automated Measurement of Crack Propagation in Composites during Mode I DCB Testing
Authors: Obaid A. Abu , Yarlagadda S. , Yoon M. K. , Hager N. E. , Domszy R. C.
Published: October 2006

This article describes a new technique for automated measurement of crack initiation, growth, and propagation in composite materials during mode I double cantilever beam (DCB) testing. The proposed method uses time-domain reflectometry (TDR) to detect changes in geometry and electromagnetic properties (dielectric or magnetic) along a transmission line that can be embedded in or bonded to the surface of the specimen. Two types of transmission line TDR sensors are evaluated (IM7 carbon fiber and ARACON) during DCB tests. A P-SPICE transmission-line simulation model is used to verify the baseline signal response for the DCB sensor and the sensitivity for crack detection, with good agreement. Comparison with standard visual methods in DCB testing showed excellent correlation in crack location, crack propagation (LC), and the interlaminar fracture toughness (GIC) values. The TDR sensor design and model-based parametric studies are carried out to determine optimal sensor geometry and configuration. The results demonstrate that the TDR-based method can measure crack propagation parameters at high resolution and accuracy, in an automated manner using low-cost sensors.
Structural Modeling and Analysis of Composite Product System: A Graph Theoretic Approach
Authors: Prabhakaran R. T. Durai , Babu B. J. , Agrawal V. P.
Published: October 2006

An attempt is made to develop an integrated systems model for the structure of the composite product system in terms of its constituents and interactions between the constituents and the molding processes, curing kinetics, etc. using graph theory and matrix algebra. The composite product system is first modeled with the help of a graph theory, then by a variable adjacency matrix and then by a multinomial known as a permanent function. The permanent function provides an opportunity to carry out structural analysis of the composite product in terms of strength, weakness, improvement, and optimization by correlating the properties of a composite with its structure. A physical meaning has been associated with each term of the permanent function. Different structural attributes of the composite product are identified to develop a graph theoretic model, a matrix model, and a multinomial permanent model of the composite. A top-down approach for complete analysis of any composite product system is also given. A general methodology is also presented for characterization and comparison of two composite product systems. Usefulness of the present methodology is also illustrated.