669 research outputs found
Smoking and tooth discolouration: findings from a national cross-sectional study
Background: Smoking is a risk factor of a number of oral diseases; the extent to which tobacco products influence dental aesthetics has not been widely investigated. The aim of this study was to determine satisfaction with own tooth colour of smokers and non-smokers and to investigate whether smokers have higher levels of self-assessed tooth discolouration compared to nonsmokersMethods: A cross sectional national study was conducted on sample of 6,000 UK adults. A total of 3,384 adults was interviewed. Smoking behaviour was recorded together with satisfaction with own tooth colour. Prevalence of perceived discolouration was measured by asking respondents to match their own tooth colour to one of a set of seven photographs of differing severities of discolouration.Results: Twenty eight percent of smokers reported having moderate and severe levels of tooth discolouration compared to 15% in non-smokers. As well as more often perceiving discolouration smokers were also more likely to be dissatisfied with their own tooth colour compared to nonsmokers.Conclusion: The study provides further evidence of the negative impact of tobacco smoking on dental aesthetics in the general public. The evidence provided by the study may be of value in short interventions for smoking cessation in the dental setting
Methane Gas Adsorption Capacity Of Carbon Materials For Adsorbed Natural Gas Applications
Adsorbed natural gas (ANG) technique was used in this study to test the adsorption capacity of carbon materials fro methane gas storage. An adsorption system based on volumetric method was designed and fabricated for this purpose. The carbon materials used were Malaysian industrial activated carbon produced from palm kernel shell and coconut shells. These materials have not been thoroughly investigated for ANG applications. Also a new material which is a composite of CNTs and activated carbon (ACNT) produced in this work along with commercial CNTs were investigated as ANG storage media.
ACNT was produced using chemical vapour deposition (CVD) method using activated carbon as catalyst substrate. The presence of activated carbon, besides being substrate, served as auxiliary storage media. This method successfully produced CNTs with diameters ranged form 25 to 70 nm and lengths, mostly, of more than 10 μm. These long tubes could be a result of the long reaction time (3 hours), thus if shorter CNTs are required, shorter reaction times should be applied.
The adsorption storage experiments were run at pressures up to 50 bar and temperatures of 30, 40 and 50 °C. The adsorption capacity on mass basis (at 35 bar and 30 °C) ranged from as low as 1.48 mmol/g for com-CNT to 6.20 mmol/g for CSAC3. ACNT showed a relatively high adsorption capacity of 4.51 mmol/g. The results indicate that there is a general trend of increasing in adsorption capacity with increasing micropore volume. However, micropore size distribution (MPSD) must be taken into account in evaluating the adsorbents.
The adsorption capacity on volume basis (V/V) ranged from 51.57 for com-CNT to 106.46 for CSAC2. These values are still below the targeted 150 V/V. While some adsorbents showed the highest adsorption capacity on mass basis compared to others (CSAC3 versus CSAC2), yet their capacity on volume basis was lower as a result of their lower bulk density. This showed the importance of this parameter in ANG applications.
The methane delivered values were 7-25% lower than the volumetric methane storage capacity. The high retention of methane gas at atmospheric pressure by some adsorbents could be explained by their narrow MPSD. Accordingly, the narrow MPSD helps in increasing the adsorption capacity, yet, the very narrow MPSD will increase the amount of gas retained.Several single component isotherm models were used to fit the experimental adsorption isotherm data. All the adsorption isotherm models used showed a good fit to the experimental data. However, Langmuir isotherm model was chosen to be used in the dynamic model to restrict the already heavy computational load from being unrealistic.
The experimental data obtained from the storage and delivery tests were compared to those obtained from process simulation using a dynamic model. The simulation model was run using the measured equilibrium data as input parameters. A good agreement was observed between experimental and simulated results. Pressure and temperature histories were acceptably well predicte
Wet Weather Impact on Trihalomethane Formation Potential in tributaries to Drinking Water Reservoirs
During rain storm events, land surface runoff and resuspension of bottom sediments cause an increase in Trihalomethane (THM) precursors in rivers. These precursors, when chlorinated at water treatment facilities will lead to the formation of THMs and hence impact drinking water resources. In order to evaluate the wet weather impact on the potential formation of THMs, river samples were collected before, during and after three rain storms ranging from 15.2 to 24.9 mm precipitation. The samples were tested for THM formation potential and other indicators including UV254 absorbance, turbidity and volatile suspended solid (VSS). Average levels of THMs increased from 61 microg/l during dry weather to 131 microg/l during wet weather, and then went back to 81 microg/l after rain ended. Wet weather values of THM are well above the maximum contaminant level (MCL) 80 microg/l, set by EPA for drinking water. THM indicators also exhibited similar trends. Average levels increased from 0.6 to 1.8 abs; 2.6 to 6 ntu; and 7.5 to 15 mg/l respectively for UV254, turbidity and VSS. A positive correlation was observed between THM formation and THM indicators. The t-test of significance (p-value) was less than 0.05 for all indicators, and R values ranged from 0.85 to 0.92 between THMs and the indicators, and 0.72 to 0.9 among indicators themselves
The Prognostic Significance of the Depth of Cervical Stromal Invasion in Women with FIGO Stage II Uterine Endometrioid Carcinoma
Purpose/Objective(s): To explore the prognostic significance of the depth of cervical stromal invasion (CSI) on survival endpoints in women with FIGO stage II uterine endometrioid adenocarcinoma.
Materials/Methods: A total of 117 patients were included in this retrospective review. Between 1990 and 2021, all patients with FIGO stage II endometrial cancer (EC) underwent hysterectomy and oophorectomy at our institution, with or without lymph node dissection. Patients with synchronous ovarian or breast cancer, as well as those who had undergone adjuvant systemic chemotherapy for EC, were excluded from the study. Pathologic slides were retrieved for these patients and were reviewed by a gynecologic pathologist to determine stromal thickness and the depth of CSI. The depth of CSI was then measured as a percentage of invasion (% CSI) and used in the analysis as a continuous or dichotomous variable (\u3c 50% vs \u3e = 50%). Patients\u27 demographics, pathologic, and treatment characteristics were analyzed using univariate and multivariate analysis to calculate recurrence-free (RFS) and disease-specific (DSS) rates.
Results: The median age for the study cohort was 65 years (range, 34–96), and the median follow-up was 131 months (range, 9–334). A total of 90 patients (77%) had lymph node dissection, with a median of 8 examined lymph nodes (range 0-18). Adjuvant radiation therapy (RT) with pelvic or vaginal cuff HDR brachytherapy, or a combination of the two, was completed in 92 patients (79 percent). The median % CSI was 27% (range, 1-100) with 68% of patients having ≥ 50% CSI. While there was a trend for a worse 5-year RFS and DSS for women with ≥ 50% CSI (69% vs. 83%, p = 0.093) and (78% vs. 91%, p = 0.034), respectively, the depth of CSI was not statistically significant as an independent predictor of 5-year RFS, DSS, or OS. The depth of CSI was not associated with a difference in the recurrence pattern (vaginal cuff, pelvic, paraaortic, or distant). In multivariate analysis, FIGO grade was the only predictor of 5-year OS. FIGO grade and the presence of lympho-vascular space invasion (LVSI) were independent predictors of 5-year RFS and DSS.
Conclusion: Deep cervical stromal invasion does not appear to be an independent predictive factor for survival endpoints in women with stage II uterine endometroid cancer, according to our findings. The presence of LVSI and tumor grade were both independent predictors of recurrence-free and disease-specific survival. Pooled data analysis may be needed to validate our study findings
Removal of imidacloprid from polluted water using adsorption and membrane separation technologies
In this work, the stability of imidacloprid in fresh water and sludge was studied. The results
revealed that the pesticide is unstable in both media. In freshwater, it underwent hydrolysis
whereas a degradation to several metabolites has been observed in sludge. The rate constants for
the hydrolysis and degradation at 25°C were 0.0.0067 and 0.0.0099 d–1, respectively. Monitoring
the degradation of imidacloprid in sludge by high-pressure liquid chromatography-mass spectrometry
(HPLC-MS) revealed that five metabolites have emerged during the study. These metabolites
include imidacloprid urea, imidacloprid-guanidine, 6-hydroxynicotinic acid, an olefin, and
5-hydroxy, 1-(6-chloro-3-pyridylmethyl)-2-(nitroimino)-imidazolidin-5-ol. The efficiency of Al-Quds
University Wastewater Treatment Plant towards the removal of imidacloprid indicates that the
ultrafiltration-hollow fiber unit was insufficient, whereas the ultrafiltration-spiral wound, activated
carbon, and reverse osmosis units were efficient for complete removal of the pesticide. Adsorption
experiments of imidacloprid using either activated charcoal or micelle-clay complex were found to
fit Langmuir isotherms better than Freundlich isotherm. The data demonstrate a higher Langmuir
Qmax value for the activated charcoal (126.6 mg g–1) when compared to the micelle-clay complex
(11.76 mg g–1). Filtration column experiments, conducted with mixed micelle-clay complex and sand
(using a ratio of 1/50 by mass) at a flow rate of 2 mL min–1 and influent concentration of 50 mg L–1,
revealed that a sufficient removal of imidacloprid was achieved in the first fraction of 100 mL
elution. These findings indicate that the adsorption technology using the micelle-clay complex
provides efficient removal of imidacloprid in continuous flow mode
Contextual influences on chronic illness: a multi-level analysis in the twin cities of Ramallah and Al Bireh in the occupied Palestinian Territory
The features of the urban environment can support human health as well as harm it, but less is known about such influences in the context of middle eastern countries. The association between green space and the political classifications of the urban environment and the risk of chronic illness was investigated in a novel setting, the twin cities of Ramallah and Albireh in the occupied Palestinian territory. We used a generalised multi-level regression analysis to link the 2017 census data with Geographic Information System data. We modelled individuals at level one (n = 54693) and areas of residence at level two (n = 228), adjusting for individual demographic and socio-economic characteristics.
The proportions of ‘mixed’ trees in residential areas had a significant inverse association with the risk of chronic illness. On the political dimension, only living in a refugee camp had a significant positive association with chronic illness; however, this was largely explained and rendered non-significant when green space variables were entered into the models. Our ability to differentiate between several types of green space was important, as findings demonstrated that not all types were associated with reduced risk of chronic illness. Our results from a middle eastern setting add to the largely Western existing evidence, that trees in urban settings are important and beneficial to human health. Researchers and policymakers should pay more attention to the health consequences of refugee camps but also the role of trees in benefiting individuals' health in such a disadvantaged context
Droplet digital PCR assay as an innovative and promising highly sensitive assay to unveil residual and cryptic HBV replication in peripheral compartment
: Droplet digital PCR is an innovative and promising approach for highly sensitive quantification of nucleic acids that is being increasingly used in the field of clinical virology, including the setting of hepatitis B virus (HBV). Here, we comprehensively report a robust and reproducible ddPCR assay for the highly sensitive quantification of serum HBV-DNA. The assay showed a limit of detection of 4 copies/ml (<1IU/ml) by Probit analysis, showed a good linearity (R2 = 0.94) and a high intra- and inter-run reproducibility with differences between the values obtained in the same run or in two independent runs never exceeding 0.14logcopies/mL and 0.21logcopies/mL, respectively. By analysing serum samples from chronically HBV infected patients (mostly under antiviral treatment), ddPCR successfully quantified serum HBV-DNA in 89.8% of patients with detectable serum HBV-DNA < 20 IU/mL [equivalent to <112copies/ml] by classical Real-Time PCR assay, with a median (IQR) of 8(5-14)IU/mL [45(28-78)copies/ml], and in 66.7% of patients with undetectable serum HBV-DNA, with a median (IQR) of 5(4-9)IU/mL [28(20-50)copies/ml]. Similarly, by analysing serum samples from patients with a serological profile compatible with occult HBV infection (anti-HBc+/HBsAg-), ddPCR successfully quantified serum HBV-DNA in 40% of patients with a median (IQR) value of 1(1-2)IU/mL [5(5-11)copies/ml], in line with the extremely limited viral replication typically observed in occult HBV infection. Overall, the availability of assays for the highly sensitive quantification of serum HBV-DNA can provide an added value in optimizing the diagnosis of occult hepatitis B infection, improving the therapeutic management of chronically HBV infected patients, also in the light of innovative drugs (upcoming in clinical practise) aimed at achieving HBV functional cure
SARS-CoV-2 variants and their relevant mutational profiles: update summer 2021
: Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic caused by it, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been undergoing a genetic diversification leading to the emergence of new variants. Nevertheless, a clear definition of the genetic signatures underlying the circulating variants is still missing. Here, we provide a comprehensive insight into mutational profiles characterizing each SARS-CoV-2 variant, focusing on spike mutations known to modulate viral infectivity and/or antigenicity. We focused on variants and on specific relevant mutations reported by GISAID, Nextstrain, Outbreak.info, Pango, and Stanford database websites that were associated with any clinical/diagnostic impact, according to published manuscripts. Furthermore, 1,223,338 full-length high-quality SARS-CoV-2 genome sequences were retrieved from GISAID and used to accurately define the specific mutational patterns in each variant. Finally, mutations were mapped on the three-dimensional structure of the SARS-CoV-2 spike protein to assess their localization in the different spike domains. Overall, this review sheds light and assists in defining the genetic signatures characterizing the currently circulating variants and their clinical relevance. IMPORTANCE Since the emergence of SARS-CoV-2, several recurrent mutations, particularly in the spike protein, arose during human-to-human transmission or spillover events between humans and animals, generating distinct worrisome variants of concern (VOCs) or of interest (VOIs), designated as such due to their clinical and diagnostic impacts. Characterizing these variants and their related mutations is important in tracking SAR-CoV-2 evolution and understanding the efficacy of vaccines and therapeutics based on monoclonal antibodies, convalescent-phase sera, and direct antivirals. Our study provides a comprehensive survey of the mutational profiles characterizing the important SARS-CoV-2 variants, focusing on spike mutations and highlighting other protein mutations
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