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A novel shape representation of the dental arch and its applications in some dentistry problems

Rijal OM, Abdullah NA, Isa ZM, Davaei FA, Noor NM, Tawfiq OF

Annu Int Conf IEEE Eng Med Biol Soc, 2011;2011:5092-5.
PMID: 22255484 DOI: 10.1109/IEMBS.2011.6091261

Standardized digital images of maxillary dental casts of 47 subjects were analyzed using MATLAB software whereby the two hamular notches and the incisive papilla defines the Cartesian vertical and horizontal axes, as well as the origin. The angle and length of the midpoints of the anterior teeth, mesiobuccal and distobuccal cusp of the posterior teeth were measured from the origin and denoted as θ(1), …, θ(18) and l(1), …, l(18) respectively. These values were collectively used to represent the shape of each dental cast. Clustering and principal component analyses were employed to find possible groups of dental arches using the above measure of shape. The main result of this study is that the 3 groups of dental arch shape may be represented by the novel feature vector v(k) = (θ(k)(1), l(k)(1), θ(k)(3), l(k)(3), θ(k)(5), l(k)(5), θ(k)(13), l(k)(13)), k = 1, 2, 3. Knowledge of v(k) implies three impression trays should be sufficient in a particular prosthetic dentistry application for Malaysian patients. Further, given that v(k) are accurately measured they may be potential candidates as evidence in specific application of forensic dentistry.
A probability distribution of shape for the dental maxillary arch using digital images

Rijal OM, Abdullah NA, Isa ZM, Noor NM, Tawfiq OF

Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:5420-3.
PMID: 23367155 DOI: 10.1109/EMBC.2012.6347220

Selected landmarks from each of 47 maxillary dental casts were used to define a Cartesian-coordinate system from which the positions of selected teeth were determined on standardized digital images. The position of the i-th tooth was defined by a line of length (l(i)) joining the tooth to the origin, and the angle (θ(i)) of this line to the horizontal Cartesian axis. Four teeth, the central incisor, lateral incisor, canine and first molar were selected and their position were collectively used to represent the shape of the dental arch. A pilot study using clustering and principal component analysis strongly suggest the existence of 3 groups of arch shape. In this study, the homogeneity of the 3 groups was further investigated and confirmed by the Dunn and Davies-Bouldein validity indices. This is followed by an investigation of the probability distribution of these 3 groups. The main result of this study suggests 3 groups of multivariate (MV) normal distribution. The MV normal probability distribution of these groups may be used in further studies to investigate the issues of variation of arch shape, which is fundamental to the practice of prosthodontics and orthodontics.
Fulltext Morphological and structural characterization of single-crystal ZnO nanorod arrays on flexible and non-flexible substrates

Farhat OF, Halim MM, Abdullah MJ, Ali MK, Allam NK

Beilstein J Nanotechnol, 2015;6:720-5.
PMID: 25821712 DOI: 10.3762/bjnano.6.73

We report a facile synthesis of zinc oxide (ZnO) nanorod arrays using an optimized, chemical bath deposition method on glass, PET and Si substrates. The morphological and structural properties of the ZnO nanorod arrays were investigated using various techniques such as field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements, which revealed the formation of dense ZnO nanorods with a single crystal, hexagonal wurtzite structure. The aspect ratio of the single-crystal ZnO nanorods and the growth rate along the (002) direction was found to be sensitive to the substrate type. The lattice constants and the crystallite size of the fabricated ZnO nanorods were calculated based on the XRD data. The obtained results revealed that the increase in the crystallite size is strongly associated with the growth conditions with a minor dependence on the type of substrate. The Raman spectroscopy measurements confirmed the existence of a compressive stress in the fabricated ZnO nanorods. The obtained results illustrated that the growth of high quality, single-crystal ZnO nanorods can be realized by adjusting the synthesis conditions.
Spatial identification and temporal prediction of air pollution sources using conditional bivariate probability function and time series signature

Althuwaynee OF, Pokharel B, Aydda A, Balogun AL, Kim SW, Park HJ

J Expo Sci Environ Epidemiol, 2021 07;31(4):709-726.
PMID: 33159165 DOI: 10.1038/s41370-020-00271-8

Accurate identification of distant, large, and frequent sources of emission in cities is a complex procedure due to the presence of large-sized pollutants and the existence of many land use types. This study aims to simplify and optimize the visualization mechanism of long time-series of air pollution data, particularly for urban areas, which is naturally correlated in time and spatially complicated to analyze. Also, we elaborate different sources of pollution that were hitherto undetectable using ordinary plot models by leveraging recent advances in ensemble statistical approaches. The high performing conditional bivariate probability function (CBPF) and time-series signature were integrated within the R programming environment to facilitate the study's analysis. Hourly air pollution data for the period between 2007 to 2016 is collected using four air quality stations, (ca0016, ca0058, ca0054, and ca0025), situated in highly urbanized locations that are characterized by complex land use and high pollution emitting activities. A conditional bivariate probability function (CBPF) was used to analyze the data, utilizing pollutant concentration values such as Sulfur dioxide (SO2), Nitrogen oxides (NO2), Carbon monoxide (CO) and Particulate Matter (PM10) as a third variable plotted on the radial axis, with wind direction and wind speed variables. Generalized linear model (GLM) and sensitivity analysis are applied to verify and visualize the relationship between Air Pollution Index (API) of PM10 and other significant pollutants of GML outputs based on quantile values. To address potential future challenges, we forecast 3 months PM10 values using a Time Series Signature statistical algorithm with time functions and validated the outcome in the 4 stations. Analysis of results reveals that sources emitting PM10 have similar activities producing other pollutants (SO2, CO, and NO2). Therefore, these pollutants can be detected by cross selection between the pollution sources in the affected city. The directional results of CBPF plot indicate that ca0058 and ca0054 enable easier detection of pollutants' sources in comparison to ca0016 and ca0025 due to being located on the edge of industrial areas. This study's CBPF technique and time series signature analysis' outcomes are promising, successfully elaborating different sources of pollution that were hitherto undetectable using ordinary plot models and thus contribute to existing air quality assessment and enhancement mechanisms.
Demystifying uncertainty in PM10 susceptibility mapping using variable drop-off in extreme-gradient boosting (XGB) and random forest (RF) algorithms

AlThuwaynee OF, Kim SW, Najemaden MA, Aydda A, Balogun AL, Fayyadh MM, et al.

Environ Sci Pollut Res Int, 2021 Aug;28(32):43544-43566.
PMID: 33834339 DOI: 10.1007/s11356-021-13255-4

This study investigates uncertainty in machine learning that can occur when there is significant variance in the prediction importance level of the independent variables, especially when the ROC fails to reflect the unbalanced effect of prediction variables. A variable drop-off loop function, based on the concept of early termination for reduction of model capacity, regularization, and generalization control, was tested. A susceptibility index for airborne particulate matter of less than 10 μm diameter (PM10) was modeled using monthly maximum values and spectral bands and indices from Landsat 8 imagery, and Open Street Maps were used to prepare a range of independent variables. Probability and classification index maps were prepared using extreme-gradient boosting (XGBOOST) and random forest (RF) algorithms. These were assessed against utility criteria such as a confusion matrix of overall accuracy, quantity of variables, processing delay, degree of overfitting, importance distribution, and area under the receiver operating characteristic curve (ROC).
Fulltext Isolation and characterization of novel microsatellite markers in commercial selected golden Malaysian arowana fish, Scleropages formosus (Osteoglossidae)

Manoharan B, Sulaimen Z, Omar F, Othman RY, Mohamed SZ, Bhassu S

Genet. Mol. Res., 2011;10(2):712-6.
PMID: 21523650 DOI: 10.4238/vol10-2gmr944

Malaysian arowana (dragonfish; Scleropages formosus) is an ancient osteoglossid fish from southeast Asia. Due to the high demand of the ornamental fish trade and because of habitat loss, the species is close to extinction. We isolated and characterized 10 polymorphic microsatellites of this species, using 5'-anchored PCR. The number of alleles at the 10 microsatellite loci ranged from 2 to 28, with a mean of 7.8/locus. The observed heterozygosity ranged from 0.03 to 0.93 (mean: 0.39), whereas the expected heterozygosity ranged from 0.03 to 0.94 (mean: 0.46). Seven microsatellites deviated from Hardy-Weinberg equilibrium, and three conformed to Hardy-Weinberg equilibrium and were in linkage equilibrium. These 10 novel microsatellites should facilitate studies of genetic diversity and population structure of arowana to help plan actions for the conservation of the indigenous Malaysian arowana.
Fulltext Nonprescription Bleaching versus Home Bleaching with Professional Prescriptions: Which One is Safer? A Comprehensive Review of Color Changes and Their Side Effects on Human Enamel

Omar F, Ab-Ghani Z, Rahman NA, Halim MS

Eur J Dent, 2019 Oct;13(4):589-598.
PMID: 31891975 DOI: 10.1055/s-0039-1700659

OBJECTIVES: This study evaluates the efficacy and safety of the professionally prescribed and nonprescription over-the-counter (OTC) bleaching agents.
MATERIALS AND: METHODS: Extracted human upper central incisors were prepared and stained with red wine for 14 days before being subjected to four different bleaching agents: professionally prescribed opalescence PF 15%, VOCO Perfect Bleach 10%, nonprescription OTC Crest 3D Whitestrips, and Whitelight Teeth Whitening System. Colorimetric measurement was performed with Vita Easyshade Handheld Spectrophotometer, enamel surface microhardness measured using Vickers Hardness machine, and surface roughness was evaluated with profilometer, before and after bleaching. Scanning electron microscope (SEM) evaluation and atomic force microscopy were conducted postbleaching.
STATISTICAL ANALYSIS: The data were analyzed with t-test, two-way ANOVA, one-way ANOVA, and Turkey's test at a significance level of 5%.
RESULTS: All bleaching products have the same efficacy to whiten stained enamel. Opalescence PF 15% showed significant increase in the microhardness (92.69 ± 68.316). All groups demonstrated significant increase in surface roughness (p < 0.05). SEM evaluation showed that Opalescence PF 15% resulted in same microscopic appearance as unbleached enamel, while VOCO Perfect Bleach 10%, Whitelight Teeth Whitening System and Crest 3D Whitestrips demonstrated mild to moderate irregularities and accentuated irregularities, respectively.
CONCLUSION: Professionally prescribed bleaching agent of Opalescence PF 15% is effective tin whitening the teeth, while the other bleaching products may be effective but also have deleterious effects on the enamel.
Fulltext Public Perception Toward COVID-19 Disease Nature, Susceptibility to Complication, and Relationship to Influenza: A Cross-Sectional Study from Yemen

Halboup AM, Alzoubi KH, Khabour OF, Alomari MA, Refat M, Al-Khazzan AY, et al.

J Multidiscip Healthc, 2023;16:707-716.
PMID: 36938485 DOI: 10.2147/JMDH.S399405

BACKGROUND: Following the coronavirus disease (COVID-19) declaration as a pandemic, Yemen has started applying preventive measures to prevent its spread. This study aims to identify the perception regarding the nature of the COVID-19 disease, susceptibility to severe forms of the disease, and its relationship to seasonal influenza among the population of Yemen.
METHODS: This was a cross-sectional study of the public in Yemen. The relationship between participants' sociodemographic factors and their responses was assessed by the chi-square test.
RESULTS: A total of 748 participants agreed to participate in the study. Regarding the nature of the diseases, nearly half of the participants (48.8%, n=352) believed that COVID-19 is a naturally occurring human virus that is a serious and fatal disease (61.2%, n=448). The majority (74.9%; n=518) did not agree that bacteria cause COVID-19. More than half of the participants (57.5%, n=423) believed this disease is transmitted to humans through a host animal. Regarding the vulnerable groups to develop severe COVID-19 infection, most of the participants pointed out that the elderly (94.3%, n=705), people with chronic diseases (89.9%, n=669), and pregnant women (53%, n=365) were more susceptible to severe diseases. Regarding symptoms, the majority (61.9%, n=458) of the participants agreed that the symptoms of COVID-19 are similar to those of seasonal influenza. Additionally, the majority (81.9%, n=579) agreed that some individuals develop more severe symptoms than seasonal influenza, particularly those with chronic illness. Gender, age, and education were found to be associated with participants' perceptions regarding the nature of the virus and susceptibility to severe disease.
CONCLUSION: Participants demonstrate a good understanding of the nature and susceptibility to complications associated with COVID-19 disease and its relationship to influenza. However, the respondents with a lower level of education might require additional educational campaigns to improve their awareness of the disease.
Fulltext Phylogeography of the smooth-coated otter (Lutrogale perspicillata): distinct evolutionary lineages and hybridization with the Asian small-clawed otter (Aonyx cinereus)

Moretti B, Al-Sheikhly OF, Guerrini M, Theng M, Gupta BK, Haba MK, et al.

Sci Rep, 2017 Jan 27;7:41611.
PMID: 28128366 DOI: 10.1038/srep41611

We investigated the phylogeography of the smooth-coated otter (Lutrogale perspicillata) to determine its spatial genetic structure for aiding an adaptive conservation management of the species. Fifty-eight modern and 11 archival (dated 1882-1970) otters sampled from Iraq to Malaysian Borneo were genotyped (mtDNA Cytochrome-b, 10 microsatellite DNA loci). Moreover, 16 Aonyx cinereus (Asian small-clawed otter) and seven Lutra lutra (Eurasian otter) were sequenced to increase information available for phylogenetic reconstructions. As reported in previous studies, we found that L. perspicillata, A. cinereus and A. capensis (African clawless otter) grouped in a clade sister to the genus Lutra, with L. perspicillata and A. cinereus being reciprocally monophyletic. Within L. perspicillata, we uncovered three Evolutionarily Significant Units and proved that L. p. maxwelli is not only endemic to Iraq but also the most recent subspecies. We suggest a revision of the distribution range limits of easternmost L. perspicillata subspecies. We show that smooth-coated otters in Singapore are L. perspicillata x A. cinereus hybrids with A. cinereus mtDNA, the first reported case of hybridization in the wild among otters. This result also provides evidence supporting the inclusion of L. perspicillata and A. cinereus in the genus Amblonyx, thus avoiding the paraphyly of the genus Aonyx.
Fulltext Chemical Items Used for Preparing Tissue-Mimicking Material of Wall-Less Flow Phantom for Doppler Ultrasound Imaging

Oglat AA, Matjafri MZ, Suardi N, Oqlat MA, Abdelrahman MA, Oqlat AA, et al.

J Med Ultrasound, 2018;26(3):123-127.
PMID: 30283197 DOI: 10.4103/JMU.JMU_13_17

The wall-less flow phantoms with recognized acoustic features (attenuation and speed of sound), interior properties, and dimensions of tissue were prepared, calibrated, and characterized of Doppler ultrasound scanning demands tissue-mimicking materials (TMMs). TMM phantoms are commercially available and ready-made for medical ultrasound applications. Furthermore, the commercial TMM phantoms are proper for ultrasound purpose or estimation of diagnostic imaging techniques according to the chemical materials used for its preparation. However, preparing a desirable TMM for wall-less flow phantom using a specific chemical material according to the specific applications is required for different flow. In this review, TMM and wall-less flow phantoms prepared using different chemical materials and methods were described. The chemical materials used in Doppler ultrasound TMM and wall-less flow phantoms fabricated over the previous decades were of high interest in this review.

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