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The concept of tooth preparation for ceramic veneers remains controversial regarding whether the use of a palatal chamfer would affect the longevity of restorations. This study aimed to evaluate the load-fatigue testing of ceramic veneers using two different preparation designs-an incisal shoulder finish line with or without a palatal chamfer. A pressable ceramic veneer was bonded to the prepared maxillary central incisor using resin cement. The number of cycles until fatigue failure for each tooth-veneer specimen was recorded. Results revealed that using a palatal chamfer margin design significantly increased the fatigue failure cycle count. Int J Prosthodont 2009;22:573-575. [ABSTRACT FROM AUTHOR]

The treatment modality, a continuous occlusal rest removable partial denture, not only restored missing teeth but also stabilized the remaining dentition in a patient with advanced periodontal attachment loss. By engaging the guiding planes at the mesial surfaces of the abutments anteriorly and also the distal surfaces of the abutments posteriorly, the remaining teeth, with varying amounts of mobility, were splinted together by the framework. This conservative treatment option allows flexibility for easy repair during the life span of the prosthesis. [ABSTRACT FROM AUTHOR]

Background: Participation in everyday activities is beneficial for mental health. However, little is known about the extent to which changes in children's participation are associated with later mental health., Objectives: To investigate the association between changes in the frequency and involvement in home, school, and community activities and subsequent mental health problems in children. Methodology: We recruited 242 school-aged children. Their parents completed the Participation and Environment Measure for Children and Youth twice, and after 2 years, they completed the Strengths and Difficulties Questionnaire., Results: After controlling for demographic factors, hierarchical regression analysis revealed that reductions in children's involvement in home and community activities were significantly associated with elevated levels of externalizing and internalizing problems. Furthermore, an increase in children's involvement in school activities showed significant relationships with better mental health outcomes., Conclusion: These findings inform participation-based interventions for occupational therapists aimed at mitigating children's future mental health problems., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

An advantage of masticators is the calibration and possible standardization of intra- and inter-individual mastication variability. However, mastication of soft, sticky and melting products, such as processed cream cheeses, is challenging to reproduce with a masticator. The objectives of this work were, for the cheese studied: (1) to compare child and adult mastication and (2) to find in vitro parameters which best reproduce their in vivo chewing. Five parameters influencing mastication (mouth volume, quantity consumed, saliva volume, mastication time and number of tongue-palate compressions) were measured in 30 children (5-12 years old) and 30 adults (18-65 years old) and compared between the two populations. They were then transposed to a masticator (Oniris device patent). The initial cheese, a homogeneous white paste, was surface-colored to investigate its in-mouth destructuring. In vivo boli were collected at three chewing stages (33, 66 and 99% of mastication time) and in vitro boli were obtained by varying the number of tongue-palate compressions and the rotation speed. In vivo and in vitro boli were compared by both image and texture analysis. Child masticatory parameters were proportionally smaller than those of adults. The in vivo child boli were less homogeneous and harder than adult ones. Comparison of in vivo and in vitro bolus color and texture enabled the successful determination of two in vitro settings that closely represented the mastication of the two populations studied.

Controlling flavor perception by analyzing volatile and taste compounds is a key challenge for food industries, as flavor is the result of a complex mix of components. Machine-learning methodologies are already used to predict odor perception, but they are used to a lesser extent to predict aroma perception. The objectives of this work were, for the processed cream cheese models studied, to (1) analyze the impact of the composition and process on the sensory perception and VOC release and (2) predict "fresh cream" aroma perception from the VOC characteristics. Sixteen processed cream cheese models were produced according to a three-factor experimental design: the texturing agent type (κ-carrageenan, agar-agar) and level and the heating time. A R-A-T-A test on 59 consumers was carried out to describe the sensory perception of the cheese models. VOC release from the cheese model boli during swallowing was investigated with an in vitro masticator (Oniris device patent), followed by HS-SPME-GC-(ToF)MS analysis. Regression trees and random forests were used to predict "fresh cream" aroma perception, i.e., one of the main drivers of liking of processed cheeses, from the VOC release during swallowing. Agar-agar cheese models were perceived as having a "milk" odor and favored the release of a greater number of VOCs; κ-carrageenan samples were perceived as having a "granular" and "brittle" texture and a "salty" and "sour" taste and displayed a VOC retention capacity. Heating induced firmer cheese models and promoted Maillard VOCs responsible for "cooked" and "chemical" aroma perceptions. Octa-3,5-dien-2-one and octane-2,3-dione were the two main VOCs that contributed positively to the "fresh cream" aroma perception. Thus, regression trees and random forests are powerful statistical tools to provide a first insight into predicting the aroma of cheese models based on VOC characteristics.

It is critical to accurately align a quantum photon detector such as a superconducting transition-edge sensor (TES) to an optical fiber in order to optimize its detection efficiency. Conventionally, such alignment requires advanced infrared imaging equipment or sophisticated microfabrication. We introduce a novel technique based on the simple idea of reflected wave intensity measurement which allows to determine the boundary of the sensor and align it accurately with the fiber. By routing a light wave through an optical fiber for normal incidence on the surface of the sensor chip, and separating the reflected wave coupled back into the fiber from the input signal with a circulator, we can observe the variation in the reflected wave intensity when the beam spot of the fiber crosses the boundary between the sensor and substrate that have different reflectivity, and adjust the position of the fiber such that its output falls on the sensor. We evaluate quantitatively the precision of our alignment method, as well as the conditions that must be met to avoid photon loss caused by light beam divergence. After demonstrating the working principle of our scheme and verifying the alignment result experimentally, we employ it for efficient input signal coupling to a TES device, which is used for photon-number-resolving measurement to showcase the successful application of our alignment method in practice. Relying on only ordinary and widely used optical elements that are easy to operate and low in cost, our solution is much less demanding than conventional methods. Dramatically easier to implement and not restricted by the detection mechanism of the sensor, it is accessible to a much broader community.

International students have the special status of being isolated in a foreign country during a pandemic. As Korea is a worldwide leader in education, it is important to understand the physical exercise behaviors of international students during this pandemic to assess the need for additional policies and support. The health belief model was used to score the physical exercise motivation and behaviors of international students in South Korea during the COVID-19 pandemic. In total, 315 valid questionnaires were obtained and analyzed for this study. The reliability and validity of the data were also assessed. For all variables, the values for combined reliability and the Cronbach's α were higher than 0.70. The following conclusions were drawn by comparing the differences between the measures. The results of the Kaiser-Meyer-Olkin and Bartlett tests were also higher than 0.70, confirming high reliability and validity. This study found a correlation between the health beliefs of international students and age, education, and accommodation. Consequently, international students with lower health belief scores should be encouraged to pay more attention to their personal health, participate in more physical exercise, strengthen their motivation to participate in physical exercise, and increase the frequency of their participation.

Conventional methods have relied on specialized imaging equipment and advanced fabrication process to solve the problem of accurately aligning a microsensor to an optical fiber which is critical for its detection efficiency. To dramatically lower the barrier to high-precision alignment, we present a technique much easier to implement and much lower in cost. By fabricating replicable alignment and proximity structures on the surface of the sensor chip, we can achieve accurate alignment and position the fiber tip very close to the sensor without damaging it. We introduce an easy setup to examine the alignment result and demonstrate accurate alignment of dummy sensors as small as 5μm×5μm. We use our alignment method to realize efficient input coupling for a superconducting transition-edge sensor as an example of fruitful adoption in many possible applications.

Background: Children with disabilities are reported to participate less in activities than their typically developing peers. However, owing to limited longitudinal studies, improvements or deteriorations in their participation over time remain unclear. No studies were also conducted in Hong Kong to describe children's activity participation over time., Aim: To investigate the changes in participation patterns of Hong Kong children with and without disabilities., Methods: Thirty-four children with disabilities and 138 without disabilities were recruited from four schools. Their parents completed the Participation and Environment Measure for Children and Youth twice over 2 years., Results: After 2 years, both groups of children were found to engage more frequently in using electronic devices and less frequently in indoor play activities/games at home. They also participated more often in school extra-curriculum activities, events and field trips. However, the frequency of community activities remained relatively stable in the two groups. No changes in their levels of involvement in almost of home, school and community activities were identified., Conclusion: The findings of increased participation in some home and school activities over time are encouraging. However, stable or possibly decreased participation of children with disabilities in other activities requires further efforts in promoting their participation., Competing Interests: Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)

In this paper, the sound transmission loss (STL) of multi-layered infinite micro-perforated plates (MPPs) is studied. A prediction model for the STL of the multi-layered infinite MPPs is developed, where each MPP may or may not have a perforation, and the number of MPPs is arbitrary. When the frequency of interest is well below the critical frequency of the plate such that the effect of flexural vibration can be neglected compared to that of the inertia term, the mass is replaced by an equivalent complex mass. For numerical examples, single-, double- and triple-layered MPPs are studied. As the perforation ratio increases, the magnitude of the equivalent complex mass decreases rapidly, which in turn results in a decrease of the STL. It is observed that for very small perforation ratios, the mass-spring resonance frequencies in double- and triple-layered MPPs move toward a higher frequency as the perforation ratios increase. In addition, the dips at the resonance frequencies become blunt with increases in the perforation ratios due to the artificial damping induced by micro-perforations. It is also found that at a high frequency, the STL shows dips regardless of the perforation ratios when the wavenumber and air gap depths satisfy certain conditions.

Background: Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality in the United States. The purpose of this study is to examine the rates of statin use for secondary prevention of ASCVD events in the United States over the last decade and determine whether disparities in the treatment of ASCVD still persist among women and racial/ethnic minorities., Methods: We conducted a trend analysis using data from 2008 through 2016 to describe age-adjusted trends in the use of statins for secondary prevention using the Medical Expenditure Panel Survey. We also conducted a multivariable logistic regression analysis to determine whether sociodemographic characteristics are associated with statin use during the 3 years that followed the publication of the 2013 American College of Cardiology/American Heart Association (ACC/AHA) guideline (2014 through 2016)., Results: The prevalence of statin use among those with a history of ASCVD remained unchanged from 2008 through 2016. In 2014 to 2016, more than 40% of those aged 40 years and older with a history of ASCVD did not use statins, corresponding to approximately 9.5 million Americans. Increasing age and having been diagnosed with high cholesterol (odds ratio [OR], 6.22; P < .001) were associated with higher odds of statin use while being female (OR, 0.65; P < .001) or Hispanic (OR, 0.69; P = .011) were associated with lower odds of statin use., Conclusions: Our study found there was no increase in the national rates of statin use following the ACC/AHA 2013 secondary prevention guideline and the availability of generic statins. Significant gender and ethnic disparities in ASCVD treatment remained in the United States., Competing Interests: Conflict of interest: none declared., (© Copyright 2019 by the American Board of Family Medicine.)

Managing of neuropathic pain remains clinically challenging because the existing pharmacotherapies are either ineffective or non-specific. Therefore, developing novel alternatives is essential for better treatment. Liquiritin is an active component extracted from Glycyrrhizae radix and has potential neuroprotective action. This study aimed to investigate the protective efficacy of liquiritin on chronic constriction injury (CCI)-induced neuropathic pain in mice. Liquiritin (30, 60, and 120mg/kg) and pregabalin (40mg/kg) were administered intragastrically for 7 consecutive days starting on the 8th day post-surgery. Behavioral parameters and sciatic functional index were assessed on days 0, 7, 8, 10, 12, and 14. Electrophysiological and histopathological changes were analyzed on the 14th day. Immunofluorescence and Western blot were used to evaluate the expression of glial cells and the protein levels of inflammatory cytokines in the spinal cord, respectively. Results showed that liquiritin dose-dependently reduced hyperalgesia and allodynia and increased the sciatic functional index and motor nerve conduction velocities. Moreover, liquiritin restored the injured axon and myelin sheath, inhibited the activation of astrocyte and microglia, down-regulated the pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin (IL-6, and IL-1β), and simultaneously up-regulated the anti-inflammatory cytokine IL-10. Our study revealed that liquiritin exerted a neuroprotective effect on CCI-induced neuropathic pain, which might be attributed to its direct protective effect on damaged nerves and its anti-inflammatory activity at the level of the spinal cord. Therefore, liquiritin shows promise as a compound for the development of novel analgesic agents that can be used to effectively treat intractable neuropathic pain., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Epilepsy is one of the common and major neurological disorders, approximately a third of the individuals with epilepsy suffer from seizures and not able to successfully respond to available medications. Current study was designed to investigate whether Swertiamarin (Swe) had anticonvulsant activity in the pilocarpine (PILO)-treated mice. Thirty minutes prior to the PILO (280 mg/kg) injection, the mice were administrated with Swe (50, 150, and 450 mg/kg) and valproate sodium (VPA, 200 mg/kg) once. Seizures and electroencephalography (EEG) were observed, and then the mice were killed for Nissl, Fluoro-jade B (FJB) staining. Astrocytic activation was examined in the hippocampus. Western blot analysis was used to examine the expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10). The results indicated that pretreatment with Swe (150, 450 mg/kg) and VPA (200 mg/kg) significantly delayed the onset of the first convulsion and reduced the incidence of status epilepticus and mortality. Analysis of EEG recordings demonstrated that Swe (150, 450 mg/kg) and VPA (200 mg/kg) sharply decreased epileptiform discharges. Furthermore, Nissl and FJB staining revealed that Swe (150, 450 mg/kg) and VPA (200 mg/kg) relieved the neuronal damage. Additionally, Swe (450 mg/kg) dramatically inhibited astrocytic activation. Western blot analysis showed that Swe (450 mg/kg) significantly decreased the expressions of IL-1β, IL-6, TNF-α and elevated the expression of IL-10. Taken together, these findings revealed that Swe exerted anticonvulsant effects on PILO-treated mice. Further studies are encouraged to investigate these beneficial effects of Swe as an adjuvant in epilepsy.

Increasing evidence demonstrates inflammation contributes to neuronal death following cerebral ischemia. Lycium barbarum polysaccharide (LBP) has been reported to prevent scopolamine-induced cognitive and memory deficits. We recently indicated that LBP exerts neuroprotective effect against focal cerebral ischemic injury in mice via attenuating the mitochondrial apoptosis pathway. The aim of this study was to investigate the neuroprotective effects of LBP against the behavioral dysfunction induced by focal cerebral ischemia injury in mice. Following 7 successive days of pretreatment with LBP (10, 20 and 40 mg/kg) and nimodipine (4 mg/kg) by intragastric gavage, mice were subjected to middle cerebral artery occlusion (MCAO). Following reperfusion, cerebral blood flows, the total power of the spontaneous EEG, and morphological changes were estimated. Learning and memory ability, and motor coordination were determined by Morris water maze task, rotarod and grip test. Western blot analysis, Real-Time fluorogenic PCR assays, and immunofluorescence staining were used to examine the expression of proinflammatory mediators and activation of microglia. The present study showed that LBP pretreatment significantly enhanced regional cortical blood flow and the total power of the spontaneous EEG, improved memory and motor coordination impairments, and inhibited over-activation of microglia and astrocytes after MCAO. Further study demonstrated LBP suppressed MCAO-induced activations of P65 NF-κB and P38 MAPK, and prevented up-regulations of proinflammatory mediators in hippocampus. Our data suggest that LBP can exert functional recovery of memory and motor coordination deficits and neuroprotective effect against cerebral ischemic injury in mice.

Perfect matching of an assembled physical sequence to a specified designed sequence is crucial to verify design principles in genome synthesis. We designed and de novo synthesized 536,024-base pair chromosome synV in the "Build-A-Genome China" course. We corrected an initial isolate of synV to perfectly match the designed sequence using integrative cotransformation and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated editing in 22 steps; synV strains exhibit high fitness under a variety of culture conditions, compared with that of wild-type V strains. A ring synV derivative was constructed, which is fully functional in Saccharomyces cerevisiae under all conditions tested and exhibits lower spore viability during meiosis. Ring synV chromosome can extends Sc2.0 design principles and provides a model with which to study genomic rearrangement, ring chromosome evolution, and human ring chromosome disorders., (Copyright © 2017, American Association for the Advancement of Science.)

Debugging a genome sequence is imperative for successfully building a synthetic genome. As part of the effort to build a designer eukaryotic genome, yeast synthetic chromosome X (synX), designed as 707,459 base pairs, was synthesized chemically. SynX exhibited good fitness under a wide variety of conditions. A highly efficient mapping strategy called pooled PCRTag mapping (PoPM), which can be generalized to any watermarked synthetic chromosome, was developed to identify genetic alterations that affect cell fitness ("bugs"). A series of bugs were corrected that included a large region bearing complex amplifications, a growth defect mapping to a recoded sequence in FIP1 , and a loxPsym site affecting promoter function of ATP2 PoPM is a powerful tool for synthetic yeast genome debugging and an efficient strategy for phenotype-genotype mapping., (Copyright © 2017, American Association for the Advancement of Science.)

Epilepsy is one of the prevalent and major neurological disorders, and approximately one-third of the individuals with epilepsy experience seizures that do not respond well to available medications. We investigated whether oxysophocarpine (OSC) had anticonvulsant and neuroprotective property in the pilocarpine (PILO)-treated mice. Thirty minutes prior to the PILO injection, the mice were administrated with OSC (20, 40, and 80 mg/kg) once. Seizures and electroencephalography (EEG) were observed, and then the mice were killed for Nissl and Fluoro-jade B (FJB) staining. The oxidative stress was measured at 24 h after convulsion. Western blot analysis was used to examine the expressions of the Bax, Bcl-2, and Caspase-3. In this study, we found that pretreatment with OSC (40, 80 mg/kg) significantly delayed the onset of the first convulsion and status epilepticus (SE) and reduced the incidence of SE and mortality. Analysis of EEG recordings revealed that OSC (40, 80 mg/kg) significantly reduced epileptiform discharges. Furthermore, Nissl and FJB staining showed that OSC (40, 80 mg/kg) attenuated the neuronal cell loss and degeneration in hippocampus. In addition, OSC (40, 80 mg/kg) attenuated the changes in the levels of Malondialdehyde (MDA) and strengthened glutathione peroxidase and catalase activity in the hippocampus. Western blot analysis showed that OSC (40, 80 mg/kg) significantly decreased the expressions of Bax, Caspase-3 and increased the expression of Bcl-2. Collectively, the findings of this study indicated that OSC exerted anticonvulsant and neuroprotective effects on PILO-treated mice. The beneficial effects should encourage further studies to investigate OSC as an adjuvant in epilepsy, both to prevent seizures and to protect neurons in brain.

In this work, three kinds of deep eutectic solvents (DESs) were facilely prepared and used in the pretreatment of corncob, including monocarboxylic acid/choline chloride, dicarboxylic acid/choline chloride and polyalcohol/choline chloride. The enhanced delignification and subsequent enzymatic hydrolysis efficiency were found to be related to the acid amount, acid strength and the nature of hydrogen bond acceptors. The XRD, SEM and FT-IR results consistently indicated that the structures of corncob were disrupted by the removal of lignin and hemicellulose in the pretreatment process. In addition, the optimal pretreatment temperature and time were 90°C and 24h, respectively. This study explored the roles of various DESs combinations, pretreatment temperature and time to better utilize the DESs in the pretreatment of lignocellulosic biomass., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Chemotherapy drugs such as vincristine (VCR) can cause neuropathic pain, and there is still lack of ideal strategy to treat it. The current study was designed to investigate effect of matrine (MT) on VCR-induced neuropathic pain in animal model. VCR (75 μg/kg, i.p. for 10 consecutive days) was administered to induce painful neuropathy model in mice. MT (15, 30 and 60 mg/kg, i.p.) and pregabalin (10 mg/kg, i.p.) were administered for 11 consecutive days. Various tests were performed to assess the degree of pain at different days (1, 6, 11, 16, and 21). Von Frey hair, hot plate, cold-plate and paw pressure tests were conducted to assess the degree of mechanical allodynia, thermal hyperalgesia, cold allodynia and mechanical hyperalgesia in the hind paw respectively. The electrophysiological and histopathological changes were also analyzed. Furthermore, tissue malondialdehyde (MDA), total antioxidant capacity (T-AOC),superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), total calcium (TCA), myeloperoxidase (MPO), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10) were measured to investigate possible involvement of MT in inflammation and oxidative stress. Administration of MT attenuated the VCR-induced behavioral alterations as well as electrophysiological and histopathological changes in a dose dependent manner. Further, MT also attenuated the VCR-induced oxidative stress (MDA, T-AOC, GSH-Px, SOD and TCA) and inflammation (MPO, TNF-α, IL-6 and IL-10). Taken together, MT ameliorated VCR-induced painful neuropathy, which might be attributed to neuroprotective effects by subsequent reduction in oxidative stress and anti-inflammatory actions.

Taurine is an abundant amino acid in the nervous system, which has been proved to possess antioxidation, osmoregulation and membrane stabilization. Previously it has been demonstrated that taurine exerts ischemic brain injury protective effect. This study was designed to investigate whether the protective effect of taurine has the possibility to be applied to treat neonatal hypoxic-ischemic brain damage. Seven-day-old Sprague-Dawley rats were treated with left carotid artery ligation followed by exposure to 8% oxygen to generate the experimental group. The cerebral damage area was measured after taurine post-treatment with 2,3,5-triphenyltetrazolium chloride (TTC) staining, Hematoxyline-Eosin (HE) staining and Nissl staining. The activities of superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), myeloperoxtidase (MPO), ATP and Lactic Acid productions were assayed with ipsilateral hemisphere homogenates. Western-blot and immunofluorescence assay were processed to detect the expressions of AIF, Cyt C, Bax, Bcl-2 in brain. We found that taurine significantly reduced brain infarct volume and ameliorated morphological injury obviously reversed the changes of SOD, MDA, GSH-Px, T-AOC, ATP, MPO, and Lactic Acid levels. Compared with hypoxic-ischemic group, it showed marked reduction of AIF, Cyt C and Bax expressions and increase of Bcl-2 after post-treatment. We conclude that taurine possesses an efficacious neuroprotective effect after cerebral hypoxic-ischemic damage in neonatal rats., (Copyright © 2016 Elsevier Inc. All rights reserved.)

In this paper, the sound transmission loss (STL) of thin double plates with an air cavity between them in a rigid duct is considered using an analytical approach. The vibration motion of the plate and sound pressure field are expanded in terms of an infinite series of the modal functions. Under the plane wave condition, a low frequency solution is derived by including the first few symmetric modes. It is determined that the peak frequencies of the double plates coincide with those of each single plate. When the two plates are identical, the STL becomes zero at the natural frequencies of the single plate. However, when the two plates are not identical, the STL is always greater than zero. The location and amplitude of the dips are investigated using an approximate solution when the cavity depth is very small. It is observed that dividing the single plate into two plates with an air cavity in between degrades the STL in the low frequency range, while the equivalent surface mass density is preserved. However, when the cavity depth is not small, the STL of the single plate can be smaller than that of the double plates.

This investigation presents a method to engineer a metamaterial exhibiting the desired anisotropic wave behavior with the specific applications toward the dispersion suppression of elastic guided waves. In the proposed approach, effective anisotropic properties required for dispersion suppression were first determined. Then the slowness curves for the metamaterial were used to find the specific unit cell configuration through inverse design. When the metamateral layers were attached to the homogeneous waveguide, the target guided mode was shown to exhibit little dispersion. Detailed engineering procedures were given, and the direct numerical simulations were performed to confirm the effectiveness of the proposed approach.

The concept of tooth preparation for ceramic veneers remains controversial regarding whether the use of a palatal chamfer would affect the longevity of restorations. This study aimed to evaluate the load-fatigue testing of ceramic veneers using two different preparation designs-an incisal shoulder finish line with or without a palatal chamfer. A pressable ceramic veneer was bonded to the prepared maxillary central incisor using resin cement. The number of cycles until fatigue failure for each tooth-veneer specimen was recorded. Results revealed that using a palatal chamfer margin design significantly increased the fatigue failure cycle count.

Statement of Problem: There is no evidence to suggest that the ferrule length needed for an all-ceramic crown is different from that needed for a cast metal or metal ceramic crown., Purpose: The purpose of this study was to relate different ferrule lengths with the number of fatigue cycles needed for failure of the crown cement for an all-ceramic crown cemented with a resin cement., Material and Methods: Fifteen maxillary central incisors were divided into 3 groups (n=5), with ferrules of 0.0 mm (no-ferrule group), 0.5 mm (0.5-mm ferrule group), and 1.0 mm (1.0-mm ferrule group), respectively. Each tooth was restored with a 0.050-inch glass-filled composite post (ParaPost FiberWhite) and a composite resin core (ParaCore). The posts were cemented with resin cement (ParaPost Cement), and the composite resin cores were bonded to dentin using a dentin bonding agent (ParaPost Cement, Conditioner A & B). Each specimen was prepared with a 7-mm total preparation height, a 1.5-mm lingual axial wall, and a 1.0-mm shoulder around the tooth. The crowns for all specimens were pressed with a pressable ceramic material (IPS Empress 2) and cemented with resin cement (Variolink II). A 6-kg cyclic test load was applied to each specimen at 135 degrees to the long axis of the tooth. The independent variable measured was the number of load fatigue cycles required for failure of the crown cement. The data were subjected to the Kruskal-Wallis test to detect overall significance and the Mann-Whitney U test for pairwise comparisons with Bonferroni correction (alpha=.017)., Results: The mean (SD) number of cycles to failure for each group was: no-ferrule group, 213 (317); 0.5-mm ferrule group, 155,137 (68,991); and 1.0-mm ferrule group, 262,872 (21,432). None of the specimens in the 1.0-mm ferrule group failed. Significant differences were found between the no-ferrule group and the 0.5-mm ferrule group, and the no-ferrule group and the 1.0-mm ferrule group (P<.017), but not between the 0.5-mm ferrule group and the 1.0-mm ferrule group (P>.017)., Conclusions: Specimens with a 0.0-mm ferrule survived few fatigue cycles despite the fact that both the post and crown were bonded with resin cement. Teeth with a 0.5-mm ferrule showed a significant increase in the number of fatigue cycles over the 0.0-mm group, whereas teeth with the 1.0-mm ferrule exhibited a significantly higher fatigue cycle count over the 0.0-mm but not the 0.5-mm group.

A novel and stable spectra derivative Kalman filter UV spectrophotometric method was proposed, and applied to the simultaneous determination of ternary mixture of phenol, 2-chlorophenol and 2,4 dichlorophenol successfully. The reasons for using spectra derivative is that it contains more information including absorbance and its change with wavelength; the obviously different signals can be caught more conveniently at the position of absorbent overlap. The noise from experiment and the errors from transfer model can be solved by Kalman filter. Calibration set with 30 standard solutions (range of 1-10 mg x L(-1)) and 61 wavelengths (260-290 m, 0.5 nm slit width) was used for each sample. The exact value of absorbance derivative was obtained from regressed simulation for the extended 8th order polynomial, and the standard work matrix of derivative spectra Kalman filter was performed from partial least-squares method. The linear discrete Kalman filter was applied to the test. The recovery experiment showed that the derivative spectra Kalman filter simultaneous determination of mixture for phenol, 2-chlorophenol and 2,4 dichlorophenol is not only exact, but also stable.

An analysis method of nonlinear absorbance for binary composition mixture was proposed. The nonlinear absorbance was composed of the contributions from both themselves and the change in their contributions due to mixing, as well as the contribution from their interaction. The mixture of phenol and 2-chlorophenol was simultaneously determined using nonlinear Kalman filter UV spectrophotometry. UV absorption spectra were obtained with 32 standard solutions (range 1-15 mg x L(-1)) and 71 wavelengths(250-290 nm). Standard work matrix of extended Kalman filter was performed from partial least-squares method. The vectors function Jacobi matrix was obtained by linearization of Taylor series for nonlinear absorbance formula. The recovery experiment showed that the extended Kalman filter simultaneous determination of mixture of phenol and 2-chlorophenol that is not only exact, but also stable.