21 research outputs found
A modified empirical criterion for strength of transversely anisotropic rocks with metamorphic origin
A modified empirical criterion is proposed to determine the strength of transversely anisotropic rocks. In this regard, mechanical properties of intact anisotropic slate obtained from three different districts of Iran were taken into consideration. Afterward, triaxial rock strength criterion introduced by Rafiai was modified for transversely anisotropic rocks. The criterion was modified by adding a new parameter α for taking the influence of strength anisotropy into consideration. The results obtained have shown that the parameter α can be considered as the strength reduction parameter due to rock anisotropy. The modified criterion was compared to the modified Hoek–Brown (Saroglou and Tsiambaos) and Ramamurthy criteria for different anisotropic rocks. It was concluded that the criterion proposed in this paper is a more accurate and precise criterion in predicting the strength of anisotropic rocks
Global burden of 369 diseases and injuries in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019
Background: In an era of shifting global agendas and expanded emphasis on non-communicable diseases and injuries along with communicable diseases, sound evidence on trends by cause at the national level is essential. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) provides a systematic scientific assessment of published, publicly available, and contributed data on incidence, prevalence, and mortality for a mutually exclusive and collectively exhaustive list of diseases and injuries. Methods: GBD estimates incidence, prevalence, mortality, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) due to 369 diseases and injuries, for two sexes, and for 204 countries and territories. Input data were extracted from censuses, household surveys, civil registration and vital statistics, disease registries, health service use, air pollution monitors, satellite imaging, disease notifications, and other sources. Cause-specific death rates and cause fractions were calculated using the Cause of Death Ensemble model and spatiotemporal Gaussian process regression. Cause-specific deaths were adjusted to match the total all-cause deaths calculated as part of the GBD population, fertility, and mortality estimates. Deaths were multiplied by standard life expectancy at each age to calculate YLLs. A Bayesian meta-regression modelling tool, DisMod-MR 2.1, was used to ensure consistency between incidence, prevalence, remission, excess mortality, and cause-specific mortality for most causes. Prevalence estimates were multiplied by disability weights for mutually exclusive sequelae of diseases and injuries to calculate YLDs. We considered results in the context of the Socio-demographic Index (SDI), a composite indicator of income per capita, years of schooling, and fertility rate in females younger than 25 years. Uncertainty intervals (UIs) were generated for every metric using the 25th and 975th ordered 1000 draw values of the posterior distribution. Findings: Global health has steadily improved over the past 30 years as measured by age-standardised DALY rates. After taking into account population growth and ageing, the absolute number of DALYs has remained stable. Since 2010, the pace of decline in global age-standardised DALY rates has accelerated in age groups younger than 50 years compared with the 1990–2010 time period, with the greatest annualised rate of decline occurring in the 0–9-year age group. Six infectious diseases were among the top ten causes of DALYs in children younger than 10 years in 2019: lower respiratory infections (ranked second), diarrhoeal diseases (third), malaria (fifth), meningitis (sixth), whooping cough (ninth), and sexually transmitted infections (which, in this age group, is fully accounted for by congenital syphilis; ranked tenth). In adolescents aged 10–24 years, three injury causes were among the top causes of DALYs: road injuries (ranked first), self-harm (third), and interpersonal violence (fifth). Five of the causes that were in the top ten for ages 10–24 years were also in the top ten in the 25–49-year age group: road injuries (ranked first), HIV/AIDS (second), low back pain (fourth), headache disorders (fifth), and depressive disorders (sixth). In 2019, ischaemic heart disease and stroke were the top-ranked causes of DALYs in both the 50–74-year and 75-years-and-older age groups. Since 1990, there has been a marked shift towards a greater proportion of burden due to YLDs from non-communicable diseases and injuries. In 2019, there were 11 countries where non-communicable disease and injury YLDs constituted more than half of all disease burden. Decreases in age-standardised DALY rates have accelerated over the past decade in countries at the lower end of the SDI range, while improvements have started to stagnate or even reverse in countries with higher SDI. Interpretation: As disability becomes an increasingly large component of disease burden and a larger component of health expenditure, greater research and developm nt investment is needed to identify new, more effective intervention strategies. With a rapidly ageing global population, the demands on health services to deal with disabling outcomes, which increase with age, will require policy makers to anticipate these changes. The mix of universal and more geographically specific influences on health reinforces the need for regular reporting on population health in detail and by underlying cause to help decision makers to identify success stories of disease control to emulate, as well as opportunities to improve. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens
Development of a Geomechanics Program for Wellbore Stability Analysis
A geomechanics program for wellbore stability analysis has been developed consisting of two modules: an analytical-based solution and a numerical-based solution. In the first part, input data are imported, including petrophysical well logs, pressure data, formation well tops, and a well path. Lithology intervals are set with proper prediction equations to calculate rock mechanical properties based on laboratory tests. In-situ stress and pore pressure are determined using different methods, including the poroelastic plane strain model and stress polygon. From the theory of plane strain, new equations are solved to determine horizontal tectonic strains (ϵ h, ϵ H) from drilling events such as total mud loss and breakout during drilling. Safe mud weight bounds are calculated through depth and in different azimuths and inclinations applying the Mohr-Coulomb and the Mogi-Coulomb failure criteria. The latter underestimated the minimum mud weight to prevent wellbore breakout. The transversely vertical isotropy of shale formation is programmed with multiple stress transformations via the weak-plane method. In the second module, a 3D model around the wellbore is discretized with hexahedral eight-point elements and programmed using the finite-element (FE) method. Rock mechanical property and displacement boundary conditions are applied to solve FE equations. Stress from the numerical model matched to the Kirsch model and results show that maximum stress concentration around the wellbore corresponds to the wellbore breakout, which has analytically been established. A new well plan across the 3D model was examined to obtain the safe mud weight bounds and results were in agreement with the analytical calculations. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Geophysics and Petrophysic
The efficacy of preventive parasternal single injection of bupivacaine on intubation time, blood gas parameters, narcotic requirement, and pain relief after open heart surgery: A randomized clinical trial study
Background: Postsurgical pain usually results in some complications in the patients. This study has tried to investigate the effects of parasternal single injection of bupivacaine on postoperative pulmonary and pain consequences in patients after open heart surgery.
Methods: : In a prospective double blind clinical study, 100 consenting patients undergoing elective open heart surgery were randomized into two groups. In case group, bupivacaine was injected at both sides of sternum, immediately before sternal closure. In the control group, no intervention was performed. Then, the patients were investigated regarding intubation period, length of ICU stay, arterial blood gas (ABG) parameters, morphine requirement, and their severity of postoperative pain using a visual analogue scale (VAS) device.
Results: No differences were found between the two groups regarding to age, sex, pump time, operation time, and body mass index and preoperative cardiac ejection fraction. Mean intubation length in case group was much shorter than that in control group. Mean PaO 2 in case group was lower in different checking times in postoperative period. The patients in the case group needed less morphine compared to those in the control group during the 24-hour observation period in the ICU. Finally, mean VAS scores of pain in case group were significantly lower than those in control group at 6, 12, and 24 hours postoperatively.
Conclusions: Patients′ pain relief by parasternal single injection of bupivacaine in early postoperative period can facilitate earlier ventilator weaning and tracheal extubation after open heart surgery as well as achieving lower pain scores and narcotic requirements
The expression of Toll-Like Receptors (TLRs) in testicular cancer: A case control study
Background: It has been suggested that malfunction of immune system may causes testicular cancer. Recently, our understanding of innate immune system has been expanded, by discovery of “Toll-Like Receptors” (TLRs). Some studies have shown that polymorphisms of TLR2 and 4 may affect on the risk of cancer. Also, the role of TLRs 3 and 9 have been shown in apoptosis and metastasis of cancer cells in animal models.\ud
Objective: Little information is available about the influence of innate immunity on testicular malignancy. Therefore, expression of TLRs 2, 3, 4 and 9 as main components of innate immunity has been investigated in this study.\ud
Materials and Methods: In this case control study, TLRs gene expression was examined by RT-PCR in normal testis and testicular cancer tissues. Real time quantitative PCR (Q-PCR) analysis was used to compare the relative expression of TLRs between the samples.\ud
Results: mRNAs of TLR 2, 3, 4 and 9 were expressed in all normal and cancer samples. Q-PCR reveals that cancer samples had stronger expression of these genes compared with normal ones.\ud
Conclusion: It seems that the different TLRs expression in testicular cancer cells may contribute to extensive signaling pathways involved in carcinogenesi
Obesity, Fat Mass, Osteopontin and Exercise Training
Obesity is a medical condition that constitutes the major risk factor for the development of insulin resistance, type 2 diabetes and subsequent diabetes-related complications such as micro- and macrovascular disease [1, 2]. Chronic low grade inflammation has been described as a fundamental component of adipose tissue expansion in obesity. Inflamed adipose tissue is characterized by enhanced secretion of cytokines and recruitment of leukocytes, in particular macrophages [3]. Current evidence suggests that these cytokines, often referred to as Adipokines, including Resistin, Visfatin, Apelin, Omentin, Chemerin, IL-6, MCP-1, PAI-1, or TNF-α link obesity to the development of systemic insulin resistance [4]. Emerging evidences suggested that Osteopontin (OPN) is a main regulator of adipose tissue inflammation, insulin resistance and diabetes mellitus.
Osteopontin (OPN), a glycoprotein was first identified in 1986 in osteoblasts. Osteopontin is a multifunctional protein, highly expressed in bone. The prefix of word ‘osteo’ indicates that the protein is expressed in bone, the suffix ‘pontin’ is derived from ‘pons’ the Latin word for bridge that signifies osteopontin’s role as a linking protein [5]. Osteopontin is also known as bone sialoprotein I (BSPI), early T-lymphocyte activation (ETA-I), Urinary stone protein, Nephropontin and Uropontin secreted phosphoprotein 1(SPP 1) and Rickettisia resistance (Ric) 44 K BPP (bone phosphoprotein) is a human gene product. Osteopontin, an extracellular structural protein is composed of ~ 300 amino acids residues and has ~ 30 carbohydrate residues attached including ten sialic acid residues. The protein is rich in acidic residues 30 – 36 % are either aspartic or glutamic acid residues. The high concentration of Osteopontin could be responsible for a number of changes within the atherosclerotic plaque that would promote plaque instability. Many key regulators of bone formation and bone structural proteins are expressed in atherosclerotic plaques, including bone morphogenetic protein-2, matrix-carboxyglutamic acid protein and OPN [6]. OPN mediates attachment of both osteoblasts and osteoclasts to bone mineral through interaction with integrin. It appears to be the result of mineralization and is involved in the inhibition of vascular calcification [7]. Chronic inflammation is a central characteristic of atherosclerosis, where oxidized lipids are considered important inflammatory stimuli. OPN is a marker of coronary artery disease activity and actively involved in plaque progression, calcification and stability [8].
Interestingly, OPN plasma levels are increased in overweight. OPN mRNA and protein are expressed in omental adipose tissue [9]. Authors observed that plasma OPN levels were increased in overweight and obese patients with the latter being further elevated in obesity associated diabetes. They demonstrated weight loss after low caloric diet, which was associated with a reduction of OPN plasma levels in obese patients. Up- regulation of OPN gene expression was demonstrated in murine obesity [10]. Obesity is associated with the development of nonalcoholic fatty liver disease. Findings suggest that in patients with severe steatosis and insulin resistance, the hepatic OPN gene expression as well as the expression of its receptor CD44 were markedly increased and related to the severity of hepatic steatosis. This progressive up-regulation of the hepatic OPN gene was significantly associated with liver injury and hepatic insulin resistance [11]. In a recent study authors demonstrated that anti-body mediated neutralization decreased obesity associated inflammation in adipose tissue and liver and reversed signal transduction related to insulin resistance and glucose homeostasis. The authors speculated that targeting OPN could provide a novel approach for the treatment of obesity related metabolic disorders [12].
Obesity is often solely attributed to lack of exercise. Exercise-induced weight loss is considered as a safe method to prevent obesity-related diseases. It was, therefore, important to explain how regular exercise modulates obesity-mediated inflammation [13]. The anti-inflammatory effects of regular exercise may be mediated via a reduction in the visceral fat mass (with a subsequent decrease in adipokines release) and the stimulation of an anti‑inflammatory environment with each exercise session [14, 15]. You JS et al (2013) reported that exercise-induced fat loss is associated with reduction of serum osteopontin concentration but was not correlated with body fat percentage in obese subjects [16]. It has been also demonstrated that OPN expression in cardiomyocytes was significantly correlated with the impaired function of the left ventricle, which was the main source of circulating OPN plasma levels [17]. Furthermore, adipokines is involved either directly or indirectly in the regulation of bone remodeling [18]. You JS et al (2013) in their study noted the change in serum leptin level induced by exercise may induce the change of bone remodeling and the change of bone metabolism may affect the serum OPN levels. In addition, caloric restriction‑induced weight loss appears to be a risk factor for rapid bone loss. However, physical activity-induced weight loss preserves bone mineral density [19].
In conclusion, serum OPN levels may be regulated by various physiological factors. Thus, the elevated expression of OPN in adipose tissues may not be correlated with serum OPN levels. Instead, other tissues or physiological factors may have a greater contribution to serum OPN levels as compared to fat mass. Thus, the correlation between serum OPN levels and body fat loss remains to be elucidated. The study of OPN as a main biomarker, may provide changes in lipid metabolism in exercise-induced weight loss in obese subjects. We encourage exercise immunology and physiology researchers to examine the theoretical constructs present here and test the hypothesis put forward
The effect of L-carnitine on sperm parameters in patients candidated for Intracytoplasmic Sperm Injection
Background: The etiologic cause in near one third of male factor
infertility is unknown. The percentage of men with idiopathic
infertility who have been successfully treated by the empirical
therapeutic modalities is not high. Objective: The aim of this study
was to assay the effect of L-carnitine on sperm parameters in patients
who needs intracytoplasmic sperm injection (ICSI) as a method for
infertility treatment. Materials and Methods: The study population
consisted of 65 men (mean age± SD: 34.4 ± 6.07) presenting
with primary infertility due to idiopathic
oligoasthenoteratozoospermia. L-carnitine was prescribed 1gram orally
every 8 hours for 3 months. Before and after the ending of the
L-carnitine treatment, semen analysis was performed. Results: The
proportion of patients who had motile and grade C sperms rose
significantly after treatment. Percentile of abnormal shaped sperms
decreased significantly after treatment. In approximately 22%, complete
asthenozoospermia changed to relative asthenozoospermia. Conclusion:
Appearing motile sperms will potentially improve the technique of ICSI.
The magnitude of the elevation in normal morphology is not clinically
obvious, but it seems that it can be important in obtaining
normal-shaped sperms for intracytoplasmic injection. Designing a study
on selected patients with complete asthenozoospermia who have not other
abnormalities in semen parameters can reveal the real effect of
carnitine therapy in this category
Prevalence of sexually transmitted infections and associated risk behaviors in prisoners: A systematic review
Abstract Background and Aims Sexually transmitted infections (STIs) are one of the major health concerns globally. Generally, prisoners are at higher risks for STIs due to risk factors including; drug‐use, high‐risk sexual behaviors, densely populated prisons, and poor living conditions. Therefore, we aimed to conduct a systematic review to evaluate the existing data on STI prevalence, and its associated risk factors among prisoners. Methods We conducted a systematic search of the literature using the keywords in Scopus, PubMed, Web of Science, and Google Scholar online databases. We selected all the relevant original studies in English through title/abstract and full‐text screening process. Results Based on the inclusion and exclusion criteria, we selected and reviewed 32 studies out of 96 identified papers. The most important STI‐associated risk factors among prisoners were drug use, low educational levels, and unsafe sex. The prevalence of STIs was heterogenous in selected studies and was reported as follows; Human Immunodeficiency Virus (HIV) (0%−14.5%), hepatitis B viruses (HBV) (0.04%−27.23%), hepatitis C viruses (HCV) (0.17%−49.7%), Syphilis (0.2%−22.1%), Chlamydia Trachomatis (CT) (1.02%−6.7%), Gonorrhea (0.6%−7.8%), and herpes simplex virus‐2 (HSV‐2) 22.4%. Conclusion This systematic review indicates that the prevalence of STIs (HIV, HBV, HCV, Syphilis, Chlamydia Trachomatis, Gonorrhea, and HSV‐2) among prisoners appears to be higher than the general population, with drug abuse, low educational levels, and unsafe sex as major risk factors
COVID-19 mortality and its predictors in the elderly: A systematic review
Background and Aims
Older people have higher rates of comorbidities and may experience more severe inflammatory responses; therefore, are at higher risk of death. Herein, we aimed to systematically review the mortality in coronavirus disease 2019 (COVID-19) patients and its predictors in this age group.
Methods
We searched PubMed, Web of Science, and Science Direct using relevant keywords. Retrieved records underwent a two-step screening process consisting of title/abstract and full-text screenings to identify the eligible studies.
Results
Summarizing findings of 35 studies demonstrated that older patients have higher mortality rates compared to the younger population. A review of articles revealed that increasing age, body mass index, a male gender, dementia, impairment or dependency in daily activities, presence of consolidations on chest X-ray, hypoxemic respiratory failure, and lower oxygen saturation at admission were risk factors for death. High d-dimer levels, 25-hydroxy vitamin D serum deficiencies, high C-reactive protein (≥5 mg/L) levels plus any other abnormalities of lymphocyte, higher blood urea nitrogen or lactate dehydrogenase, and higher platelet count were predictors of poor prognosis and mortality in the elderly. Studies have also shown that previous treatment with renin–angiotensin–aldosterone system inhibitors, pharmacological treatments of respiratory disorders, antibiotics, corticosteroids, vitamin K antagonist, antihistamines, azithromycin, Itolizumab (an anti-CD6 monoclonal antibody) in combination with other antivirals reduces COVID-19 worsening and mortality. Vaccination against seasonal influenza might also reduce COVID-19 mortality.
Conclusion
Overall, a critical consideration is necessary for the care and management of COVID-19 in the aged population considering the drastic contrasts in manifestation and prognosis compared to other age groups. Mortality from COVID-19 is independently associated with the patient's age. Elderly patients with COVID-19 are more vulnerable to poor outcomes. Thus, strict preventive measures, timely diagnosis, and aggressive therapeutic/nontherapeutic care are of great importance to reduce acute respiratory distress syndrome and severe complications in older people.publishedVersio