Thermal refugia against coral bleaching throughout the northern Red Sea.

Tropical reefs have been impacted by thermal anomalies caused by global warming that induced coral bleaching and mortality events globally. However, there have only been very few recordings of bleaching within the Red Sea despite covering a latitudinal range of 15° and consequently it has been considered a region that is less sensitive to thermal anomalies. We therefore examined historical patterns of sea surface temperature (SST) and associated anomalies (1982-2012) and compared warming trends with a unique compilation of corresponding coral bleaching records from throughout the region. These data indicated that the northern Red Sea has not experienced mass bleaching despite intensive Degree Heating Weeks (DHW) of >15°C-weeks. Severe bleaching was restricted to the central and southern Red Sea where DHWs have been more frequent, but far less intense (DHWs <4°C-weeks). A similar pattern was observed during the 2015-2016 El Niño event during which time corals in the northern Red Sea did not bleach despite high thermal stress (i.e. DHWs >8°C-weeks), and bleaching was restricted to the central and southern Red Sea despite the lower thermal stress (DHWs < 8°C-weeks). Heat stress assays carried out in the northern (Hurghada) and central (Thuwal) Red Sea on four key reef-building species confirmed different regional thermal susceptibility, and that central Red Sea corals are more sensitive to thermal anomalies as compared to those from the north. Together, our data demonstrate that corals in the northern Red Sea have a much higher heat tolerance than their prevailing temperature regime would suggest. In contrast, corals from the central Red Sea are close to their thermal limits, which closely match the maximum annual water temperatures. The northern Red Sea harbours reef-building corals that live well below their bleaching thresholds and thus we propose that the region represents a thermal refuge of global importance.

The potential association between periodontitis and non-alcoholic fatty liver disease: a systematic review.

OBJECTIVES: Many animal and human studies have shown associations between periodontitis and non-alcoholic fatty liver disease (NAFLD). Hence, the present systematic review sought to investigate such a potential association. METHODS: PubMed/Medline, Scopus, Embase, and Web of Science databases were thoroughly searched to identify all relevant studies. The eligibility criteria were all observational (cross-sectional studies, case-control, cohort studies, and case reports) and interventional studies that assessed the relationship between periodontitis and NAFLD in humans. Due to remarkable heterogeneity and inconsistency among the included studies, no statistical analyses were conducted. RESULTS: A total of 12 studies comprising 53,384 patients were included in the present systematic review. The sample size in the individual studies ranged from 52 to 24,470 patients. All studies except one found significant associations between clinical and/or microbial periodontal parameters and NAFLD. Eight studies found significant associations between clinical periodontal parameters and NAFLD. Four microbial studies found a significant association between periodontal pathogens, especially Porphyromonas gingivalis and NAFLD development and progression. CONCLUSIONS: The available evidence suggests that periodontitis may be a risk factor for development and progression of NAFLD. However, due to limited number of prospective cohort studies included in this review along with the substantial heterogeneity among the included studies, further well-designed prospective cohort studies are highly warranted. CLINICAL RELEVANCE: Given the potential association between periodontitis and NAFLD, it can be assumed that healthy periodontium may be essential for liver health.

De novo regeneration of dentin pulp complex mediated by Adipose derived stem cells in an immunodeficient albino rat model (Histological, histochemical and scanning electron microscopic Study).

Background: Dental tissue engineering is an alternative procedure for restoring damaged dental tissues. Adipose-derived stem cells are a new source of cells for regenerative endodontics in combination with scaffold materials. The descriptive data about this regenerative process is still insufficient. Objective: To evaluate the regenerative potential of Adipose-derived stem cells using a self-assembling polypeptide scaffold for the dentin-pulp complex in an emptied root canal space. Material and Methods: 40 root segments of human single-rooted teeth were transplanted into the albino rats' dorsal subcutaneous tissue. Root segments were divided into two groups: group I contained only a self-assembling polypeptide scaffold, and group II contained fluorescent-labeled Adipose-derived stem cells embedded in a self-assembling polypeptide scaffold. The newly formed tissues were assessed on the 60th and 90th days post-transplantation using routine histological examination, Masson trichrome staining, and scanning electron microscopy. Results: Group I showed granulation tissue without any signs of predentin formation or odontoblast-like cells. Group II revealed the presence of predentin tissue along the dentin margin, with arranged odontoblast-like cells. An organized connective tissue with abundant vasculature and calcific masses was observed in the pulp space. Conclusion: Adipose-derived stem cells can be considered as alternative stem cells for regenerating the dentin-pulp complex. Dentin pulp complex regeneration utilizing a self-assembling polypeptide scaffold alone would not yield successful results.

Effects of gamma radiation on hard dental tissues of albino rats: investigation by light microscopy.

The present work aims at studying the effect of gamma radiation on the hard dental tissues. Eighty adult male albino rats with weights of about 250 g were used. The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy whole-body gamma doses. The effects on hard dental tissue samples were investigated after 48 h in histological and ground sections using light microscopy. Areas of acid phosphatase activity were detected using tartrate-resistant acid phosphatase (TRAP) stains. Observation of histological sections revealed disturbance in predentin thickness and odontoblastic layer as the irradiation dose increased. In cementum, widened cementocytes lacunae were occasionally detected even with low irradiated doses. On the other hand, relatively homogenous enamel was detected with darkened areas in enamel surface at doses over than 0.5 Gy. TRAP-positive cells were detected on the surface of the dentin of irradiated groups as well as cementum surface. Minimal detectable changes were observed in ground sections.

Effects of dose-dependent response to gamma radiation on circumvallate papilla by expression of caspase-3 in vivo.

BACKGROUND: Radiotherapy is one of the most significant treatment modality of head and neck cancers. However, it has various hazards on the normal tissues in the radiation field. One of these affected tissues is the lingual mucosa with their papillae such as circumvallate papilla. The effects of radiation on the lingual specialized mucosa may be represented by radiation-induced mucositis and taste alteration including partial or complete loss of taste. OBJECTIVES: The aim of the study was to evaluate the dose-dependent response of circumvallate papillae to gamma radiation by immunohistochemical expression of caspase-3. MATERIAL AND METHODS: Twenty-four adult male albino rats were divided into 3 equal groups irradiated at 2.0, 4.0 and 6.0 Gy whole-body gamma radiation doses. Six non-irradiated rats were used as the control group. The radiation effects on circumvallate papillae were evaluated three days after irradiation via histomorphometric investigation of the papillary size and taste buds' distortion in addition to an immunohistochemical assessment of the apoptotic activity using Caspase-3 marker. RESULTS: Dose-related changes were observed in the circumvallate papillae size and morphology and taste buds affection. The changes were obviously detected in rats irradiated at 4 Gy and 6 Gy doses. The detection of caspase-3 marker was evident in a dose-dependent manner in all the irradiated groups, more noticeably in the taste bud cells. CONCLUSIONS: It could be concluded that circumvallate papillae are adversely affected in a dose-dependent manner by gamma radiation particularly in 4 Gy and 6 Gy doses.

Cephalometric comparison of dentofacial parameters between Yemeni and Caucasian adults / Comparação cefalométrica de parâmetros dentofaciais entre adultos iemenitas e caucasianos

Objective: The purposes of our research were to establish cephalometric standards for Yemeni adults and to compare them with those of the Caucasians. Material and Methods: 100 Yemeni students (fifty males, mean age of 23.6 ± 2.1 years, and fifty female, mean age of 21.5 ± 3.1 years) with normal occlusions and well-balanced faces were involved in the study. Inclusion criteria were a class I occlusion with minor or no crowding, the whole teeth is present except third molars and no previous orthodontic, orthopedic or maxillofacial surgery treatment. Five angular and eighteen linear measurements were used for the skeletal, dental and soft tissue analysis. All participant's Lateral cephalometric radiographs were evaluated. The average values and standard deviations for all the angles and linear measurements were determined. The differences for each measurement between the Yemeni and Caucasian participants were calculated using unpaired t­tests. Results: Yemeni subjects had a more retrognathic mandibular positions (P< 0.05), protrusive mandibular incisors (P< 0.01), more protruded lip positions (P < 0.01), deeper mentolabial sulci (P< 0.01) and a steeper mandibular planes (P< 0.001) compared to the Caucasians. Yemeni females had a larger lower face height than Caucasian females (P< 0.001). Conclusions The study provides specific standards for Yemeni adults and shows that the Yemenis had different skeletal and dentoalveolar cephalometric standards in comparison with Caucasians (AU)

Objetivo: O objetivo de nossa pesquisa foi estabelecer padrões cefalométricos para adultos iemenitas e compará-los com os caucasianos. Material e Métodos: Cem estudantes iemenitas (cinquenta homens, idade média de 23,6 ± 2,1 anos, e cinquenta mulheres, idade média de 21,5 ± 3,1 anos) com oclusões normais e faces bem equilibradas foram envolvidos no estudo. Os critérios de inclusão foram: oclusão de classe I com pouco ou nenhum apinhamento, todos os dentes presentes, exceto terceiros molares e sem histórico de tratamento ortodôntico, ortopédico ou cirurgia maxilo-facial prévio. Cinco medidas angulares e dezoito lineares foram utilizadas para a análise esquelética, dentária e de tecidos moles. Todas as radiografias cefalométricas laterais dos participantes foram avaliadas. Foram determinados os valores médios e desvios padrão para todos os ângulos e medidas lineares. As diferenças para cada medição entre os participantes iemenitas e caucasianos foram calculadas usando testes t não pareados. Resultados: Os indivíduos iemenitas tinham posições mandibulares mais retrognáticas (P <0,05), incisivos inferiores protrusivos (P <0,01), posições dos lábios mais protuberantes (P <0,01), sulcos mentolabiais mais profundos (P <0,01) e planos mandibulares mais inclinados (P <0,001) em comparação com os caucasianos. As mulheres iemenitas tinham uma altura facial inferior maior do que as mulheres brancas (P <0,001). Conclusão:O estudo fornece padrões específicos para adultos iemenitas e mostra que os iemenitas apresentaram padrões cefalométricos esqueléticos e dentoalveolares diferentes em comparação com os caucasianos. (AU)

Assessing uncertainty in pollutant wash-off modelling via model validation.

Stormwater pollution is linked to stream ecosystem degradation. In predicting stormwater pollution, various types of modelling techniques are adopted. The accuracy of predictions provided by these models depends on the data quality, appropriate estimation of model parameters, and the validation undertaken. It is well understood that available water quality datasets in urban areas span only relatively short time scales unlike water quantity data, which limits the applicability of the developed models in engineering and ecological assessment of urban waterways. This paper presents the application of leave-one-out (LOO) and Monte Carlo cross validation (MCCV) procedures in a Monte Carlo framework for the validation and estimation of uncertainty associated with pollutant wash-off when models are developed using a limited dataset. It was found that the application of MCCV is likely to result in a more realistic measure of model coefficients than LOO. Most importantly, MCCV and LOO were found to be effective in model validation when dealing with a small sample size which hinders detailed model validation and can undermine the effectiveness of stormwater quality management strategies.

A Bayesian regression approach to assess uncertainty in pollutant wash-off modelling.

Due to knowledge gaps in relation to urban stormwater quality processes, an in-depth understanding of model uncertainty can enhance decision making. Uncertainty in stormwater quality models can originate from a range of sources such as the complexity of urban rainfall-runoff-stormwater pollutant processes and the paucity of observed data. Unfortunately, studies relating to epistemic uncertainty, which arises from the simplification of reality are limited and often deemed mostly unquantifiable. This paper presents a statistical modelling framework for ascertaining epistemic uncertainty associated with pollutant wash-off under a regression modelling paradigm using Ordinary Least Squares Regression (OLSR) and Weighted Least Squares Regression (WLSR) methods with a Bayesian/Gibbs sampling statistical approach. The study results confirmed that WLSR assuming probability distributed data provides more realistic uncertainty estimates of the observed and predicted wash-off values compared to OLSR modelling. It was also noted that the Bayesian/Gibbs sampling approach is superior compared to the most commonly adopted classical statistical and deterministic approaches commonly used in water quality modelling. The study outcomes confirmed that the predication error associated with wash-off replication is relatively higher due to limited data availability. The uncertainty analysis also highlighted the variability of the wash-off modelling coefficient k as a function of complex physical processes, which is primarily influenced by surface characteristics and rainfall intensity.

Uncertainty analysis of pollutant build-up modelling based on a Bayesian weighted least squares approach.

Reliable pollutant build-up prediction plays a critical role in the accuracy of urban stormwater quality modelling outcomes. However, water quality data collection is resource demanding compared to streamflow data monitoring, where a greater quantity of data is generally available. Consequently, available water quality datasets span only relatively short time scales unlike water quantity data. Therefore, the ability to take due consideration of the variability associated with pollutant processes and natural phenomena is constrained. This in turn gives rise to uncertainty in the modelling outcomes as research has shown that pollutant loadings on catchment surfaces and rainfall within an area can vary considerably over space and time scales. Therefore, the assessment of model uncertainty is an essential element of informed decision making in urban stormwater management. This paper presents the application of a range of regression approaches such as ordinary least squares regression, weighted least squares regression and Bayesian weighted least squares regression for the estimation of uncertainty associated with pollutant build-up prediction using limited datasets. The study outcomes confirmed that the use of ordinary least squares regression with fixed model inputs and limited observational data may not provide realistic estimates. The stochastic nature of the dependent and independent variables need to be taken into consideration in pollutant build-up prediction. It was found that the use of the Bayesian approach along with the Monte Carlo simulation technique provides a powerful tool, which attempts to make the best use of the available knowledge in prediction and thereby presents a practical solution to counteract the limitations which are otherwise imposed on water quality modelling.

Assessment of Gingival Health Status among 5- and 12-Year-Old Children in Yemen: A Cross-Sectional Study.

Purpose. There are limited data about the gingival health status in Yemeni children. The aim, therefore, was to assess oral hygiene status and prevalence and severity of gingivitis among Yemeni preschool and school children. Materials and Methods. A total of 5396 children were included from 5 representative Yemeni governorates: Sana'a, Hajjah, Hodeida, Hadramaut, and Taiz. Five-year olds (1292) were recruited from private kindergartens while 12-year olds (4104) were selected from public primary schools. Gingival health status was assessed using the plaque index (PI), calculus index (CAI), and gingival index (GI) on the 6 Ramfjord teeth. The latter index was used to categorize gingivitis severity at the subject level. Data were analyzed using simple hypothesis testing, as well as ordinal regression. Results. The 12-year old children had significantly much higher mean PI, CAI, and GI (P < 0.001) with 78.6% presenting with gingivitis and 47.8% with moderate gingivitis. In contrast, the figures were 27.2% and 3.1% in the younger group (P < 0.001). There were significant variations according to gender, area of residence, and governorate. Regression analysis revealed that mean PI (OR = 35), mean CAI (OR = 7.7), male gender (OR = 1.6), living in rural areas (OR = 1.4), and being from Hajjah or Sana'a were independent risk factors of gingivitis severity in the older group. For the 5-year olds, the determinants were mean PI (OR = 122), male gender (OR = 1.4), and living in Sana'a or Taiz. Conclusions. Bad oral hygiene and moderate gingivitis are highly prevalent among Yemeni preschool and school children. Geographical location appeared as important independent risk factors of gingival inflammation.