Marginal Adaptation and Color Stability of Four Provisional Materials

Purpose:  A number of provisional restorative materials exist on the market. This study tested marginal fit and color stability of three provisional restorative materials and a control. Materials and Methods:  Two auto-cure materials, Protemp Garant and Integrity, and one dual-cure material, Luxatemp Solar, were tested against SNAP, a polyethyl methacrylate control. A maxillary right central incisor ivorine tooth was prepared for a full coverage all-ceramic crown, with a 1.5-mm chamfer margin. Four points were engraved at a point 1 mm below the facial, lingual, mesial, and distal margins, and replicas (n = 40) were produced by the manufacturer. Provisional crowns (n = 10 × 4) were fabricated on the individual replicas using a polyethylene coping template. The crowns were trimmed under magnification using an acrylic bur. The distance from the crown margins to a point tangent to the engraved markings was measured under 10× magnification and recorded. For color stability, 10-mm diameter × 2-mm thick discs (n = 10 × 4) were fabricated and immersed cyclically in tea for 1 week in a Tucillo/Nielson apparatus. Color measurements were recorded for each specimen at baseline and after staining. ΔE values were calculated to determine the extent of the color change. Results:  The means of the four marginal discrepancy measurements for each specimen were analyzed using a 1-way ANOVA and Tukey post-hoc comparison. Luxatemp Solar had statistically significant marginal discrepancy (319 Μm, p < 0.05) when compared to the other provisional materials. A significant color change (ΔE = 4.33, p < 0.05) was found for Protemp Garant. Conclusion:  The dual-cure temporary material (Luxatemp Solar) exhibited significantly more discrepancy at the margin than the auto-cure bis-acryl materials or acrylic control. Protemp Garant exhibited a clinically noticeable change in shade after 1 week in staining solution, whereas the other materials did not exhibit a clinically noticeable change. Clinical Implications:  Provisional crowns fabricated from SNAP, Protemp Garant, and Integrity exhibited similarly low marginal discrepancy. SNAP, Luxatemp Solar, and Integrity did not demonstrate a clinically detectable change in shade after 1 week in a staining solution.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74793/1/j.1532-849X.2007.00256.x.pd

Toward ab initio density functional theory for nuclei

We survey approaches to nonrelativistic density functional theory (DFT) for nuclei using progress toward ab initio DFT for Coulomb systems as a guide. Ab initio DFT starts with a microscopic Hamiltonian and is naturally formulated using orbital-based functionals, which generalize the conventional local-density-plus-gradients form. The orbitals satisfy single-particle equations with multiplicative (local) potentials. The DFT functionals can be developed starting from internucleon forces using wave-function based methods or by Legendre transform via effective actions. We describe known and unresolved issues for applying these formulations to the nuclear many-body problem and discuss how ab initio approaches can help improve empirical energy density functionals.Comment: 69 pages, 16 figures, many revisions based on feedback. To appear in Progress in Particle and Nuclear Physic

A study of the impact of building geometry on the thermal performance of road pavement solar collectors

Studies on RPSC (road pavement solar collectors) have shown the potential of reducing the UHI (urban heat island) effects by dissipating the heat from the pavement for energy harness. Several works have shown that the generated heat could be utilised for sustainable urban energy system. However, none of the previous literatures have assessed the effect of building geometry on the performance of the RPSC. This study investigates the thermal performance of an urban-integrated RPSC system by using CFD (computational fluid dynamic) simulation of integrated RPSC system with a standard urban canyon domain and an empty domain. Based on 21st June at 13:00, it was found that the RPSC system in urban canyon domain was on average 36.08% more effective in thermal collection and provided on average 27.11% more surface temperature reduction as compared to the RSPC application in rural/flat domain. The RPSC performance based on the effect from daily solar intensity was initiated with results demonstrated the efficiency of the RPSC in an urban setting was 7.14%–63.26% more than the rural/flat setting. Simulations of various wind speeds in summer day(s) and the impact of seasonal changes to the RPSC system were also conducted to investigate the deficiency factors to the system

Spintronics: Fundamentals and applications

Spintronics, or spin electronics, involves the study of active control and manipulation of spin degrees of freedom in solid-state systems. This article reviews the current status of this subject, including both recent advances and well-established results. The primary focus is on the basic physical principles underlying the generation of carrier spin polarization, spin dynamics, and spin-polarized transport in semiconductors and metals. Spin transport differs from charge transport in that spin is a nonconserved quantity in solids due to spin-orbit and hyperfine coupling. The authors discuss in detail spin decoherence mechanisms in metals and semiconductors. Various theories of spin injection and spin-polarized transport are applied to hybrid structures relevant to spin-based devices and fundamental studies of materials properties. Experimental work is reviewed with the emphasis on projected applications, in which external electric and magnetic fields and illumination by light will be used to control spin and charge dynamics to create new functionalities not feasible or ineffective with conventional electronics.Comment: invited review, 36 figures, 900+ references; minor stylistic changes from the published versio

Identification of IGF1, SLC4A4, WWOX, and SFMBT1 as Hypertension Susceptibility Genes in Han Chinese with a Genome-Wide Gene-Based Association Study

Hypertension is a complex disorder with high prevalence rates all over the world. We conducted the first genome-wide gene-based association scan for hypertension in a Han Chinese population. By analyzing genome-wide single-nucleotide-polymorphism data of 400 matched pairs of young-onset hypertensive patients and normotensive controls genotyped with the Illumina HumanHap550-Duo BeadChip, 100 susceptibility genes for hypertension were identified and also validated with permutation tests. Seventeen of the 100 genes exhibited differential allelic and expression distributions between patient and control groups. These genes provided a good molecular signature for classifying hypertensive patients and normotensive controls. Among the 17 genes, IGF1, SLC4A4, WWOX, and SFMBT1 were not only identified by our gene-based association scan and gene expression analysis but were also replicated by a gene-based association analysis of the Hong Kong Hypertension Study. Moreover, cis-acting expression quantitative trait loci associated with the differentially expressed genes were found and linked to hypertension. IGF1, which encodes insulin-like growth factor 1, is associated with cardiovascular disorders, metabolic syndrome, decreased body weight/size, and changes of insulin levels in mice. SLC4A4, which encodes the electrogenic sodium bicarbonate cotransporter 1, is associated with decreased body weight/size and abnormal ion homeostasis in mice. WWOX, which encodes the WW domain-containing protein, is related to hypoglycemia and hyperphosphatemia. SFMBT1, which encodes the scm-like with four MBT domains protein 1, is a novel hypertension gene. GRB14, TMEM56 and KIAA1797 exhibited highly significant differential allelic and expressed distributions between hypertensive patients and normotensive controls. GRB14 was also found relevant to blood pressure in a previous genetic association study in East Asian populations. TMEM56 and KIAA1797 may be specific to Taiwanese populations, because they were not validated by the two replication studies. Identification of these genes enriches the collection of hypertension susceptibility genes, thereby shedding light on the etiology of hypertension in Han Chinese populations

Sequencing of high-complexity DNA pools for identification of nucleotide and structural variants in regions associated with complex traits

We have used targeted genomic sequencing of high-complexity DNA pools based on long-range PCR and deep DNA sequencing by the SOLiD technology. The method was used for sequencing of 286 kb from four chromosomal regions with quantitative trait loci (QTL) influencing blood plasma lipid and uric acid levels in DNA pools of 500 individuals from each of five European populations. The method shows very good precision in estimating allele frequencies as compared with individual genotyping of SNPs (r(2) = 0.95, P &lt; 10(-16)). Validation shows that the method is able to identify novel SNPs and estimate their frequency in high-complexity DNA pools. In our five populations, 17% of all SNPs and 61% of structural variants are not available in the public databases. A large fraction of the novel variants show a limited geographic distribution, with 62% of the novel SNPs and 59% of novel structural variants being detected in only one of the populations. The large number of population-specific novel SNPs underscores the need for comprehensive sequencing of local populations in order to identify the causal variants of human traits

Deep-Learning–Based Pre-Diagnosis Assessment Module for Retinal Photographs: A Multicenter Study

PURPOSE: Artificial intelligence (AI) deep learning (DL) has been shown to have significant potential for eye disease detection and screening on retinal photographs in different clinical settings, particular in primary care. However, an automated pre-diagnosis image assessment is essential to streamline the application of the developed AI-DL algorithms. In this study, we developed and validated a DL-based pre-diagnosis assessment module for retinal photographs, targeting image quality (gradable vs. ungradable), field of view (macula-centered vs. optic-disc-centered), and laterality of the eye (right vs. left). METHODS: A total of 21,348 retinal photographs from 1914 subjects from various clinical settings in Hong Kong, Singapore, and the United Kingdom were used for training, internal validation, and external testing for the DL module, developed by two DL-based algorithms (EfficientNet-B0 and MobileNet-V2). RESULTS: For image-quality assessment, the pre-diagnosis module achieved area under the receiver operating characteristic curve (AUROC) values of 0.975, 0.999, and 0.987 in the internal validation dataset and the two external testing datasets, respectively. For field-of-view assessment, the module had an AUROC value of 1.000 in all of the datasets. For laterality-of-the-eye assessment, the module had AUROC values of 1.000, 0.999, and 0.985 in the internal validation dataset and the two external testing datasets, respectively. CONCLUSIONS: Our study showed that this three-in-one DL module for assessing image quality, field of view, and laterality of the eye of retinal photographs achieved excellent performance and generalizability across different centers and ethnicities. TRANSLATIONAL RELEVANCE: The proposed DL-based pre-diagnosis module realized accurate and automated assessments of image quality, field of view, and laterality of the eye of retinal photographs, which could be further integrated into AI-based models to improve operational flow for enhancing disease screening and diagnosis