82 research outputs found
Space Cooling Using Geothermal Single-Effect Water/Lithium Bromide Absorption Chiller
Abstract This research is proposed to fully investigate the performance of a single‐effect water/lithium bromide absorption chiller driven by geothermal energy. Since absorption cycles are considered as low‐grade energy cycles, this innovative idea of rejecting fluid from a single‐flash geothermal power plant with low‐grade energy would serve as efficient, economical, and promising technology. In order to examine the feasibility of this approach, a residential building which is located in Sharjah, UAE, considered to evaluate its cooling capacity of 39 kW which is calculated using MATLAB software. Based on the obtained cooling load, modeling of the required water/lithium bromide single‐effect absorption chiller machine is implemented and discussed. A detailed performance analysis of the proposed model under different conditions is performed using Engineering Equation Solver software (EES). Based on the obtained results, the major factors in the design of the proposed system are the size of the heat exchangers and the input heat source temperature. The results are presented graphically to find out the geofluid temperature and mass flow and solution heat exchanger effectiveness effects on the chiller thermal performance. Moreover, the effects of the size of all components of the absorption chiller on the cooling load to meet the space heating are presented. The thermal efficiency of the single‐flash geothermal power plant is about 13% when the power plant is at production well temperature 250℃, separator pressure 0.24 MPa, and condenser pressure 7.5 kPa. The results show that the coefficient of performance (COP) reaches about 0.87 at solution heat exchanger effectiveness of 0.9, when the geofluid temperature is 120℃
Parametric Study of a Single Effect Lithium Bromide-Water Absorption Chiller Powered by a Renewable Heat Source
This work investigates the performance of a single-effect absorption chiller utilizing an aqueous lithium bromide solution as the working fluid and driven by hot fluid rejected from either a geothermal power plant or the outlet of a thermal solar collector. This relatively low enthalpy return fluid, which will otherwise be reinjected back into the
earth, will be utilized as the thermal energy source of the chiller. Although such chillers are considered low-grade energy refrigeration cycles, the one proposed here has an advantage in terms of economy and efficiency. A parametric analysis is performed using Engineering Equation Solver software and is used to highlight the effect of the heat
exchanger size on the coefficient of performance of the chiller. The analysis proved that the proposed device can operate with excellent cooling capacity, reaching 16 kW, and a relatively high coefficient of performance (~ 0.7) while being driven by the low-grade energy. The heat source temperature, solution heat exchanger effectiveness and the size of the absorber were shown to be key parameters for the design and operation of absorption chillers. Moreover, increasing the heat source mass flow rate has a significant impact on both cooling capacity and coefficient of performance at low values (< 10 kg/s)
and unnoticeable impact at higher values (> 10 kg/s)
Developmental characteristics of the permanent upper lateral incisor in unilateral cleft lip and palate
Objectives: This study aims to provide insights into the developmental characteristics of the upper lateral incisor in individuals with unilateral clefts. Materials and methods: Panoramic radiographs of a consistent group of Caucasian children taken over time (ages 6, 9, and 12) were extensively reviewed. The study assessed the distribution pattern, eruption path, tooth development, and crown size of the upper lateral incisor within the cleft region. Results: The most commonly observed distribution pattern was the lateral incisor located distal to the cleft, accounting for 49.2% of cases. Furthermore, a significant delay in tooth development of the upper lateral incisor on the cleft side was noted at ages 6 and 9 (p > 0.001). Compared with the non-cleft side, these incisors often erupted along the alveolar cleft and exhibited microdontia (88.3%, p < 0.041). Conclusion: Lateral incisors on the cleft side display unique distribution patterns, microdontia, and delayed tooth development. Careful monitoring of the cuspid eruption is essential, as it can influence the eruption of the lateral incisor. Clinical relevance: A comprehensive understanding of the development of the upper lateral incisor relative to the cleft is vital for determining its prognosis over time. The position of the upper lateral incisor can also influence the timing and prognosis of secondary alveolar bone grafting. Preserving the upper lateral incisor favors arch length, perimeter, and symmetry in individuals with unilateral clefts.</p
Determinants of Pain-Induced Disability in German Women with Endometriosis during the COVID-19 Pandemic
(1) Background: The main aim of this research was to examine the factors leading to pain induced disability by assessing the impact of demographic, endometriosis-specific, pandemic-specific,
and mental health factors. (2) Methods: Women with endometriosis who attended online support
groups were invited to respond to an online survey during the first wave of the COVID-19 pandemic in
Germany. The Pain Disability Index (PDI) was employed to assess disability-related daily functioning.
Independent predictors of pain-induced disability were determined using univariate and multivariate
logistic regression analyses. (3) Results: The mean PDI score of the study population was 31.61
(SD = 15.82), which was significantly higher (p < 0.001) than that reported in a previously published
normative study of the German population. In the present study, a high level of pain-induced
disability, as defined by scores equal to or higher than the median of the study population, older age
(OR 1.063, 95% CI 1.010–1.120, p = 0.020), dysmenorrhea (OR 1.015, 95% CI 1.005–1.026, p = 0.005),
dysuria (OR 1.014; 95% CI 1.001–1.027, p = 0.029), lower back pain (OR 1.018, 95% CI 1.007–1.029,
p = 0.001), and impaired mental health (OR 1.271, 95% CI 1.134–1.425, p < 0.001) were found to be
independent risk factors. Pandemic-specific factors did not significantly influence the pain-induced
disability of the participants in this study. (4) Conclusions: The level of pain-induced disability was
significantly higher among the women with endometriosis than among women in the normative
German validation study. Our findings identified risk factors for experiencing a high level of pain induced disability, such as demographic and specific pain characteristics. Pandemic-specific factors
did not significantly and independently influence the pain-induced disability during the first wave
of the COVID-19 pandemic in Germany. Impaired mental health negatively influenced functioning
during daily activities. Thus, women with endometriosis should be managed by a multidisciplinary
team of healthcare professionals to prevent negative effects of pain-induced disability on their
quality of life
Factors Associated with Increased Analgesic Use in German Women with Endometriosis during the COVID-19 Pandemic
(1) Background: Endometriosis is a frequent chronic pain condition in women of fertile
age. Pain management with analgesics is frequently used by women with endometriosis. During the
COVID-19 pandemic, access to health services was temporarily restricted in various countries for
persons without serious conditions, resulting in increased physical and mental health issues. The
present study was conducted in order to assess the risk factors predicting increased analgesic intake
by women with endometriosis during the COVID-19 pandemic. (2) Methods: The increased intake
of over-the-counter (OTC) and prescription-only (PO) analgesics was assessed with an anonymous
online questionnaire, along with demographic, pandemic-specific, disease-specific, and mental health
characteristics. Anxiety and depression were assessed with the Generalized Anxiety Disorder Scale
(GAD-2) and the Patient Health Questionnaire for Depression (PHQ-2), respectively. Pain-induced
disability was assessed with the pain-induced disability index (PDI). (3) Results: A high educational
level (OR 2.719; 95% CI 1.137–6.501; p = 0.025) and being at higher risk for depressive disorders, as
measured by PHQ-2 ≥ 3 (OR 2.398; 95% CI 1.055–5.450; p = 0.037), were independent risk factors
for an increased intake of OTC analgesics. Current global pain-induced disability (OR 1.030; 95% CI
1.007–1.054; p = 0.010) was identified as a risk factor for an increased intake of PO pain medication.
The degree of reduction in social support and in social networks were independent predictors of an
increased intake of PO analgesics in a univariate logistic regression analysis, but lost significance
when adjusted for additional possible influencing factors. (4) Conclusions: In this population, an
increased intake of OTC analgesics was related to a higher educational level and having a depressive
disorder, while a higher pain-induced disability was an independent risk factor for an increased
intake of PO analgesics. Pandemic-specific factors did not significantly and independently influence
an increased intake of analgesics in women with endometriosis during the first wave of the COVID19 pandemic in Germany. Healthcare providers should be aware of the possible factors related to
increased analgesic use in women with endometriosis in order to identify persons at risk for the
misuse of pain medication and to prevent potential adverse effects
Current Approaches to the Management of Sentinel Node Procedures in Early Vulvar Cancer in Germany : A Web-Based Nationwide Analysis of Practices
Background: Lymph node involvement is the most important prognostic factor for recurrence and survival in vulvar cancer. Sentinel node (SN) procedure can be offered in well-selected
patients with early vulvar cancer. This study aimed to assess current management practices with
respect to the sentinel node procedure in women with early vulvar cancer in Germany. Methods: A
Web-based survey was conducted. Questionnaires were e-mailed to 612 gynecology departments.
Data were summarized as frequencies and analyzed using the chi-square test. Results: A total of
222 hospitals (36.27%) responded to the invitation to participate. Among the responders, 9.5% did
not offer the SN procedure. However, 79.5% evaluated SNs by ultrastaging. In vulvar cancer of the
midline with unilateral localized positive SN, 49.1% and 48.6% of respondents, respectively, would
perform ipsilateral or bilateral inguinal lymph node dissection. Repeat SN procedure was performed
by 16.2% of respondents. For isolated tumor cells (ITCs) or micrometastases, 28.1% and 60.5% of
respondents, respectively, would perform inguinal lymph node dissection, whereas 19.3% and 23.8%,
respectively, would opt for radiation without further surgical intervention. Notably, 50.9% of respondents would not initiate any further therapy and 15.1% would opt for expectant management.
Conclusions: The majority of German hospitals implement the SN procedure. However, only 79.5%
of respondents performed ultrastaging and only 28.1% were aware that ITC may affect survival in
vulvar cancer. There is a need to ensure that the management of vulvar cancer follows the latest
recommendations and clinical evidence. Deviations from state-of-the-art management should only
be after a detailed discussion with the concerned patient
Global, regional, and national burden of chronic kidney disease, 1990–2017 : a systematic analysis for the Global Burden of Disease Study 2017
Background
Health system planning requires careful assessment of chronic kidney disease (CKD) epidemiology, but data for morbidity and mortality of this disease are scarce or non-existent in many countries. We estimated the global, regional, and national burden of CKD, as well as the burden of cardiovascular disease and gout attributable to impaired kidney function, for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017. We use the term CKD to refer to the morbidity and mortality that can be directly attributed to all stages of CKD, and we use the term impaired kidney function to refer to the additional risk of CKD from cardiovascular disease and gout.
Methods
The main data sources we used were published literature, vital registration systems, end-stage kidney disease registries, and household surveys. Estimates of CKD burden were produced using a Cause of Death Ensemble model and a Bayesian meta-regression analytical tool, and included incidence, prevalence, years lived with disability, mortality, years of life lost, and disability-adjusted life-years (DALYs). A comparative risk assessment approach was used to estimate the proportion of cardiovascular diseases and gout burden attributable to impaired kidney function.
Findings
Globally, in 2017, 1·2 million (95% uncertainty interval [UI] 1·2 to 1·3) people died from CKD. The global all-age mortality rate from CKD increased 41·5% (95% UI 35·2 to 46·5) between 1990 and 2017, although there was no significant change in the age-standardised mortality rate (2·8%, −1·5 to 6·3). In 2017, 697·5 million (95% UI 649·2 to 752·0) cases of all-stage CKD were recorded, for a global prevalence of 9·1% (8·5 to 9·8). The global all-age prevalence of CKD increased 29·3% (95% UI 26·4 to 32·6) since 1990, whereas the age-standardised prevalence remained stable (1·2%, −1·1 to 3·5). CKD resulted in 35·8 million (95% UI 33·7 to 38·0) DALYs in 2017, with diabetic nephropathy accounting for almost a third of DALYs. Most of the burden of CKD was concentrated in the three lowest quintiles of Socio-demographic Index (SDI). In several regions, particularly Oceania, sub-Saharan Africa, and Latin America, the burden of CKD was much higher than expected for the level of development, whereas the disease burden in western, eastern, and central sub-Saharan Africa, east Asia, south Asia, central and eastern Europe, Australasia, and western Europe was lower than expected. 1·4 million (95% UI 1·2 to 1·6) cardiovascular disease-related deaths and 25·3 million (22·2 to 28·9) cardiovascular disease DALYs were attributable to impaired kidney function.
Interpretation
Kidney disease has a major effect on global health, both as a direct cause of global morbidity and mortality and as an important risk factor for cardiovascular disease. CKD is largely preventable and treatable and deserves greater attention in global health policy decision making, particularly in locations with low and middle SDI
Windei, the Drosophila Homolog of mAM/MCAF1, Is an Essential Cofactor of the H3K9 Methyl Transferase dSETDB1/Eggless in Germ Line Development
The epigenetic regulation of gene expression by the covalent modification of histones is a fundamental mechanism required for the proper differentiation of germ line cells during development. Trimethylation of histone 3 lysine 9 (H3K9me3) leads to chromatin silencing and the formation of heterochromatin by recruitment of heterochromatin protein 1 (HP1). dSETDB1/Eggless (Egg), the ortholog of the human methyltransferase SETDB1, is the only essential H3K9 methyltransferase in Drosophila and is required for H3K9 trimethylation in the female germ line. Here we show that Windei (Wde), the Drosophila homolog of mouse mAM and human MCAF1, is an essential cofactor of Egg required for its nuclear localization and function in female germ line cells. By deletion analysis combined with coimmunoprecipitation, we have identified the protein regions in Wde and Egg that are necessary and sufficient for the interaction between the two proteins. We furthermore identified a region of Egg that gets covalently modified by SUMOylation, which may facilitate the formation of higher order chromatin-modifying complexes. Together with Egg, Wde localizes to euchromatin, is enriched on chromosome 4, and binds to the Painting of fourth (POF) protein. Our data provide the first genetic and phenotypic analysis of a mAM/MCAF1 homolog in a model organism and demonstrate its essential function in the survival of germ line cells
The global, regional, and national burden of oesophageal cancer and its attributable risk factors in 195 countries and territories, 1990-2017: A systematic analysis for the global burden of disease study 2017
© 2020 The Author(s). Background Oesophageal cancer is a common and often fatal cancer that has two main histological subtypes: oesophageal squamous cell carcinoma and oesophageal adenocarcinoma. Updated statistics on the incidence and mortality of oesophageal cancer, and on the disability-adjusted life-years (DALYs) caused by the disease, can assist policy makers in allocating resources for prevention, treatment, and care of oesophageal cancer. We report the latest estimates of these statistics for 195 countries and territories between 1990 and 2017, by age, sex, and Socio-demographic Index (SDI), using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD). Methods We used data from vital registration systems, vital registration-samples, verbal autopsy records, and cancer registries, combined with relevant modelling, to estimate the mortality, incidence, and burden of oesophageal cancer from 1990 to 2017. Mortality-to-incidence ratios (MIRs) were estimated and fed into a Cause of Death Ensemble model (CODEm) including risk factors. MIRs were used for mortality and non-fatal modelling. Estimates of DALYs attributable to the main risk factors of oesophageal cancer available in GBD were also calculated. The proportion of oesophageal squamous cell carcinoma to all oesophageal cancers was extracted by use of publicly available data, and its variation was examined against SDI, the Healthcare Access and Quality (HAQ) Index, and available risk factors in GBD that are specific for oesophageal squamous cell carcinoma (eg, unimproved water source and indoor air pollution) and for oesophageal adenocarcinoma (gastro-oesophageal reflux disease). Findings There were 473 000 (95% uncertainty interval [95% UI] 459 000-485 000) new cases of oesophageal cancer and 436 000 (425 000-448 000) deaths due to oesophageal cancer in 2017. Age-standardised incidence was 5.9 (5.7-6.1) per 100 000 population and age-standardised mortality was 5.5 (5.3-5.6) per 100 000. Oesophageal cancer caused 9.78 million (9.53-10.03) DALYs, with an age-standardised rate of 120 (117-123) per 100 000 population. Between 1990 and 2017, age-standardised incidence decreased by 22.0% (18.6-25.2), mortality decreased by 29.0% (25.8-32.0), and DALYs decreased by 33.4% (30.4-36.1) globally. However, as a result of population growth and ageing, the total number of new cases increased by 52.3% (45.9-58.9), from 310 000 (300 000-322 000) to 473 000 (459 000-485 000); the number of deaths increased by 40.0% (34.1-46.3), from 311 000 (301 000-323 000) to 436 000 (425 000-448 000); and total DALYs increased by 27.4% (22.1-33.1), from 7.68 million (7.42-7.97) to 9.78 million (9.53-10.03). At the national level, China had the highest number of incident cases (235 000 [223 000-246 000]), deaths (213 000 [203 000-223 000]), and DALYs (4.46 million [4.25-4.69]) in 2017. The highest national-level agestandardised incidence rates in 2017 were observed in Malawi (23.0 [19.4-26.5] per 100 000 population) and Mongolia (18.5 [16.4-20.8] per 100 000). In 2017, age-standardised incidence was 2.7 times higher, mortality 2.9 times higher, and DALYs 3.0 times higher in males than in females. In 2017, a substantial proportion of oesophageal cancer DALYs were attributable to known risk factors: tobacco smoking (39.0% [35.5-42.2]), alcohol consumption (33.8% [27.3-39.9]), high BMI (19.5% [6.3-36.0]), a diet low in fruits (19.1% [4.2-34.6]), and use of chewing tobacco (7.5% [5.2-9.6]). Countries with a low SDI and HAQ Index and high levels of indoor air pollution had a higher proportion of oesophageal squamous cell carcinoma to all oesophageal cancer cases than did countries with a high SDI and HAQ Index and with low levels of indoor air pollution. Interpretation Despite reductions in age-standardised incidence and mortality rates, oesophageal cancer remains a major cause of cancer mortality and burden across the world. Oesophageal cancer is a highly fatal disease, requiring increased primary prevention efforts and, possibly, screening in some high-risk areas. Substantial variation exists in age-standardised incidence rates across regions and countries, for reasons that are unclear
Mapping child growth failure across low- and middle-income countries
Child growth failure (CGF), manifested as stunting, wasting, and underweight, is associated with high 5 mortality and increased risks of cognitive, physical, and metabolic impairments. Children in low- and middle-income countries (LMICs) face the highest levels of CGF globally. Here we illustrate national and subnational variation of under-5 CGF indicators across LMICs, providing 2000–2017 annual estimates mapped at a high spatial resolution and aggregated to policy-relevant administrative units and national levels. Despite remarkable declines over the study period, many LMICs remain far from the World Health 10 Organization’s ambitious Global Nutrition Targets to reduce stunting by 40% and wasting to less than 5% by 2025. Large disparities in prevalence and rates of progress exist across regions, countries, and within countries; our maps identify areas where high prevalence persists even within nations otherwise succeeding in reducing overall CGF prevalence. By highlighting where subnational disparities exist and the highest-need populations reside, these geospatial estimates can support policy-makers in planning locally 15 tailored interventions and efficient directing of resources to accelerate progress in reducing CGF and its health implications
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