RESUMO
In addition to zero-carbon generation, the plummeting cost of renewable energy sources (RES) is enabling the increased use of distributed-generation sources. Although the RES appear to be a cheaper source of energy, without the appropriate design of the RES with a true understanding of the nature of the load, they can be an unreliable and expensive source of energy. Limited research has been aimed at designing small-scale hybrid energy systems for irrigation pumping systems, and these studies did not quantify the water requirement, or in turn the energy required to supply the irrigation water. This paper provides a comprehensive feasibility analysis of an off-grid hybrid renewable energy system for the design of a water-pumping system for irrigation applications in Sudan. A systematic and holistic framework combined with a techno-economic optimization analysis for the planning and design of hybrid renewable energy systems for small-scale irrigation water-pumping systems is presented. Different hybridization cases of solar photovoltaic, wind turbine and battery storage at 12 different sites in Sudan are simulated, evaluated, and compared, considering the crop water requirement for different crops, the borehole depth, and the stochasticity of renewable energy resources. Soil, weather, and climatic data from 12 different sites in Sudan were used for the case studies, with the key aim to find the most robust and reliable solution with the lowest system cost. The results of the case studies suggest that the selection of the system is highly dependent on the cost, the volatility of the wind speed, solar radiation, and the size of the system; at present, hybridization is not the primary option at most of sites, with the exception of two. However, with the reduction in price of wind technology, the possibility of hybrid generation will rise.
RESUMO
BACKGROUND: Pre-operative radiographic assessment of the anatomical relationship between the roots of the mandibular third molar and the inferior alveolar nerve (IAN) is a must to minimize the risk of IAN injury during surgery. OBJECTIVES: To compare the radiographic signs of digital orthopantomogram (OPG) and cone-beam computed tomography (CBCT). An additional objective was to assess the cortex status between the mandibular canal and third molar on CBCT images in relation to the demographic characteristics, region (right or left side), and angulation of mandibular molar. METHODOLOGY: In this retrospective study, a total of 350 impacted mandibular third molars with a close relationship between the inferior alveolar canal (IAC) and impacted mandibular third molars on digital OPG were further referred for CBCT imaging for assessment of the position of the mandibular canal. The study was conducted between August 2018 and February 2020. Digital OPGs were evaluated for radiographic signs like interruption of the mandibular canal wall, darkening of the roots, diversion of the mandibular canal, and narrowing of the mandibular canal. The age and sex of patients, site of impacted third molar, Winter's classification of mandibular third molar, position of IAC relative to impacted molar, and the radiographic markers of OPG were assessed for cortical integrity using CBCT. Chi square testing was applied to study the values of difference and binomial logistic regression was done to assess the factors associated with cortication. Statistical significance was set at p ≤ 0.05. RESULTS: Among 350 patients, 207 (59.1%) were male and 143 (40.9%) were female with a mean age of 36.8 years. The most common OPG sign was interruption of white line, seen in 179 (51.1%) cases. In total, 246 cases (70.3%) showed an absence of canal cortication between the mandibular canal and the impacted third molar on CBCT images. Cortication was observed in all cases with a combination of panoramic signs which was statistically significant (p = 0.047). Cortication was observed in 85 (50.6%) cases where IAC was positioned on the buccal side, 11 (16.9%) in cases of inferiorly positioned IAC, and just 8 (7.6%) for cases of lingually positioned IAC which was statistically significant (p = 0.003). Statistically insignificant (p > 0.05) results were noted for cortex status in CBCT images with regards to the age, sex, site, and angulation of impacted third molars. CONCLUSION: CBCT imaging is highly recommended for those cases where diversion of the mandibular canal is observed on OPG and when the roots are present between canals.
RESUMO
The aim of the study was to investigate the unstimulated whole saliva (UWS) tumor necrosis factor alpha (TNF-α) and cellular micronuclei in snuff dippers (Naswar) compared to healthy control subjects. The case control study was conducted over 9 months at a tertiary care center. Sixty patients were divided into two groups: Snuff dippers (SD) (Naswar) and non-snuff dippers (NSD) (control subjects). The included self-reported SD used Snuff twice daily for more than 12 months. UWS was collected and salivary TNF-α assessment was performed using enzyme-linked immunosorbent assay (ELISA). For cellular micronuclei, buccal mucosa was brushed to obtain cells in Naswar users, fixed with a dibutylphthalate polystyrene xylene (DPX) mounting to view micronuclei. Means and standard deviations were compared using the t-test and outcomes were related using Pearson correlation, considering p ≤ 0.05 as significant. The mean age of participants was 38.85 ± 11.56 years. The mean duration of snuff use was 20.43 ± 12.79 years and the common site for Naswar placement was the lower vestibule (n = 19, 63.3%). TNF-α levels among SD were 9.6 ± 3.3 pg/mL, which were significantly higher than levels in NSD, 5.2 ± 3 pg/mL (p < 0.05). The number of cellular micronuclei in SD was 30.7 ± 7.8, which was comparatively higher than in NSD, which was 9.2 ± 3.3 (p < 0.05). The duration of snuff use was positively correlated to TNF-α levels (p = 0.048) rather than the micronuclei number (p = 0.97). SD showed higher levels of TNF-α and cellular micronuclei compared with NSD (control subjects); a positive correlation was shown with the duration of snuff use. We conclude that TNF-α and micronuclei are potential salivary biomarkers for an oral biological effect in snuff (Naswar) users.
