Amir Ghaderi

Estimation of thickness and velocity changes of injected carbon dioxide layers from prestack time-lapse seismic data

In this study, we bring together the two main categories of time-lapse seismic analysis — amplitude analysis and time-shift analysis — to estimate simultaneously the changes in thickness and velocity of a 4D seismic anomaly. The methodology is applied to time-lapse seismic monitoring of carbon dioxide (C O2 ) storage at Sleipner field, Norway, that shows significant 4D effects. The 4D anomalies resulting from C O2 injection appear as a multilayer reflection pattern within the relatively shallow Utsira Sand. This multireflective appearance within the sand layer is interpreted as C O2 layers trapped below thin shale layers. Because most of the C O2 layers are believed to be thin (0–20 m) , the interference between top and base of these layers needs to be taken into account in 4D seismic analysis. By studying the reflected event from a horizon below the Utsira Sand, we estimate 4D traveltime shifts caused by the presence of the C O2 layer above thishorizon. We then combine these traveltime shifts with measur...

Pre-stack estimation of time-lapse seismic velocity changes — An example from the Sleipner CO2-Sequestration Project

Publisher Summary For compacting reservoirs like the Ekofisk field, travel time shifts up to 18 ms have been observed. In the Sleipner CO 2 -sequestration project even larger time shifts are observed. For such cases, one finds that pre-stack analysis might be a useful complement for precise time shift estimation. A detailed method for estimation of relative velocity changes within a reservoir layer from pre-stack time-lapse seismic data is presented. By estimating travel time shifts on constant offset gathers between two interpreted horizons, it is possible to estimate the average velocity change within the section between the interpreted horizons. Both from theory and measurements, it is found that the pre-stack method gives smaller velocity changes when estimated between two key horizons. Therefore it is recommended to do pre-stack travel time analysis in addition to conventional post- stack analysis if possible. For a selected seismic inline for the Sleipner CO 2 Project, estimate a maximum velocity change of 9% based on pre-stack seismic analysis, while a conventional post-stack analysis gives 14 to 16%.

Velocity and thickness estimation of thin CO2 layers with uniform and patchy saturations - A 4D synthetic seismic study

Summary Thin accumulations of CO2 layers below shale layers gives rise to prominent 4D seismic anomalies. The thin CO2 layers are typically within the tuning limit hence causing complicated reflection and amplitude patterns. A model developed for estimation of velocities and thicknesses of CO2 layers is extended and shown to be sensitive to patchy saturations in the CO2 -layers.

The Effects of Vitamin D Supplementation on Biomarkers of Inflammation and Oxidative Stress in Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

In this systematic review and meta-analysis of randomized controlled trials (RCTs), the effects of vitamin D supplementation on biomarkers of inflammation and oxidative stress in diabetic patients are summarized. The following databases were searched up to December 2017: MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials. The quality of the relevant extracted data was assessed according to the Cochrane risk of bias tool. Data were pooled using the inverse variance method and expressed as mean difference with 95% Confidence Intervals (95% CI). Heterogeneity between studies was assessed by the Cochran Q statistic and I-squared tests (I2). Overall, 33 studies were included in the meta-analyses. Vitamin D supplementation were found to significantly reduce serum high-sensitivity C-reactive protein (hs-CRP) (WMD 0.27; 95% CI, - 0.35, - 0.20; p<0.001) and malondialdehyde (MDA) levels (WMD - 0.43, 95% CI - 0.62, - 0.25, p<0.001) in diabetic patients. In addition, vitamin D supplementation were found to increase markers of nitric oxide (NO) release (WMD 4.33, 95% CI 0.96, 7.70), total serum antioxidant capacity (TAC) (WMD 57.34, 95% CI 33.48, 81.20, p<0.001) and total glutathione (GSH) levels (WMD 82.59, 95% CI 44.37, 120.81, p<0.001). Overall, this meta-analysis shows that in diabetic patients, taking vitamin D had significant effects on hs-CRP and MDA levels, and significantly increased NO, TAC and GSH levels.

Clinical trial of the effects of vitamin D supplementation on psychological symptoms and metabolic profiles in maintenance methadone treatment patients

BACKGROUND Vitamin D deficiency may be associated with some complications including nonspecific musculoskeletal pain and periodontal disease in maintenance methadone treatment (MMT) patients. This study was designed to determine the effect of vitamin D supplementation on psychological symptoms and metabolic profiles in MMT patients. METHODS This randomized, double-blind, placebo-controlled, clinical trial was carried out among 68 MMT patients. Participants were randomly allocated to receive either 50,000IU vitamin D supplements (n=34) or placebo (n=34) every 2weeks for 12weeks. Fasting blood samples were taken at baseline and post-intervention to evaluate relevant variables. RESULTS After the 12-week intervention, serum 25(OH) vitamin D levels significantly increased in the intervention group compared with the placebo group (+8.1±4.9 vs. -0.4±3.0, P<0.001). In addition, vitamin D supplementation significantly improved Pittsburgh Sleep Quality Index (-1.5±2.2 vs. -0.2±2.3, P=0.02) and Beck Depression Inventory (-4.8±7.3 vs. -1.5±6.1, P=0.04) compared with the placebo. Patients who received vitamin D supplements had significantly decreased fasting plasma glucose (-7.5±10.6 vs. +0.3±10.7mg/dL, P=0.004), serum insulin levels (-3.6±5.3 vs. -0.9±3.5 μIU/mL, P=0.01), homeostasis model of assessment-insulin resistance (-1.0±1.3 vs. -0.2±0.7, P=0.003), serum triglycerides (-9.6±30.8 vs. +15.6±30.2mg/dL, P=0.001), total- (-8.7±20.9 vs. +11.0±27.4mg/dL, P=0.001) and LDL-cholesterol (-11.1±17.9 vs. +5.9±27.5mg/dL, P=0.004) compared with the placebo. Additionally, vitamin D intake resulted in a significant decrease in serum high sensitivity C-reactive protein (-2.2±4.2 vs. +2.0±3.7mg/L, P<0.001), and significant increases plasma total antioxidant capacity (+26.2±99.8 vs. -86.3±127.5mmol/L, P<0.001) and glutathione levels (+292.3±172.4 vs. +48.9±208.9μmol/L, P<0.001) compared with the placebo. There was no significant effect of vitamin D supplementation on serum HDL-cholesterol, and other markers of insulin metabolism, inflammation and oxidative stress. CONCLUSIONS Totally, taking 50,000IU vitamin D supplement every 2weeks for 12weeks in MMT patients had beneficial effects on psychological symptoms and few metabolic profiles.

The effects of combined sertraline and aspirin therapy on depression severity among patients with major depressive disorder: A randomized clinical trial

Background Different studies have been conducted to find the best adjuvant therapies for depression management. There are controversies over the effects of aspirin as an adjuvant therapy for depression. Objective To determine the effects of combined sertraline and aspirin therapy on depression severity among patients with major depressive disorder. Methods This randomized clinical trial was conducted at Kargarnejad Psychiatric Hospital in Kashan, Isfahan, Iran, from September 1, 2016 to November 1, 2016. The study participants included 100 patients with major depressive disorder who were assigned to aspirin and placebo groups by the use of computer-generated random numbers. Patients in these groups respectively received sertraline-aspirin and sertraline-placebo for eight consecutive weeks. Patients were prescribed 80 milligrams of aspirin twice a day. Also, sertraline was administered at a dose of 50-200 milligrams daily. Beck Depression Inventory was employed for depression severity assessment at four time points, namely before, two, four, and eight weeks after the beginning of the intervention. Medication side effects were also assessed eight weeks after the beginning of the intervention. Data were analyzed by SPSS version 12.0, using Chi-square and the Independent-samples t-test (α=0.05). Results Both groups were matched in terms of age (p=0.46), gender (p=0.539), and depression severity (p=0.509, with mean score 33.5±4.1 vs. 32.8±5.9) at baseline. However, depression scores were reduced significantly four and eight weeks after initiation of therapy just in the sertraline-aspirin group (p<0.05). Conclusion As an adjuvant therapy, aspirin can reduce depression severity among patients with major depressive disorder. Yet, further studies are needed to prove the effectiveness of aspirin and other anti-inflammatory agents in reducing depression severity. Trial registration The trial was registered at the Iranian Registry of Clinical Trials (http://www.irct.ir) with the IRCT ID: IRCT2016082829556N1. Funding The authors received financial support from Research Deputy of Kashan University of Medical Sciences, Kashan, Isfahan, Iran.

The effects of melatonin supplementation on mental health, metabolic and genetic profiles in patients under methadone maintenance treatment: Melatonin and MMT

This investigation was designed to determine the effect of melatonin supplementation on mental health parameters, metabolic and genetic profiles in patients under methadone maintenance treatment (MMT). This randomized, double‐blind, placebo‐controlled, clinical trial was conducted among 54 patients under MMT. Participants were randomly allocated to receive either 10 mg melatonin (2 melatonin capsules, 5 mg each) (n = 26) or placebo (n = 28) once a day, 1 hour before bedtime for 12 weeks. Melatonin supplementation significantly decreased Pittsburgh Sleep Quality Index (β −4.08; 95 percent CI, −5.51, −2.65; P < 0.001), Beck Depression Inventory index (β −5.46; 95% CI, −8.92, −2.00; P = 0.003) and Beck Anxiety Inventory index (β −3.87; 95% CI, −5.96, −1.77; P = 0.001) and significantly increased International Index of Erectile Functions (β 5.59; 95% CI, 1.76, 9.42; P = 0.005) compared with the placebo. Subjects who received melatonin supplements had significantly lower serum insulin levels (β −2.53; 95% CI, −4.48, −0.59; P = 0.01), homeostasis model of assessment‐insulin resistance (β −0.56; 95% CI, −1.03, −0.09; P = 0.01) and higher quantitative insulin sensitivity check index (β 0.01; 95% CI, 0.004, 0.02; P = 0.009) and HDL‐cholesterol levels (β 3.71; 95% CI, 1.77, 5.64; P = 0.002) compared to placebo. Additionally, melatonin intake resulted in a significant reduction in serum high sensitivity C‐reactive protein (β −0.15; 95% CI, −0.27, −0.02; P = 0.02), malondialdehyde (β −0.31; 95% CI, −0.57, −0.05; P = 0.02) and protein carbonyl (β −0.06; 95% CI, −0.09, −0.04; P < 0.001). This trial indicated that taking melatonin supplements for 12 weeks by patients under MMT had beneficial effects on their mental health metabolic profiles.

Quantitative seismic characterization of CO2 at the Sleipner storage site, North Sea

AbstractReliable quantification of carbon dioxide (CO2) properties and saturation is crucial in the monitoring of CO2 underground storage projects. We have focused on quantitative seismic characterization of CO2 at the Sleipner storage pilot site. We evaluate a methodology combining high-resolution seismic waveform tomography, with uncertainty quantification and rock physics inversion. We use full-waveform inversion (FWI) to provide high-resolution estimates of P-wave velocity VP and perform an evaluation of the reliability of the derived model based on posterior covariance matrix analysis. To get realistic estimates of CO2 saturation, we implement advanced rock physics models taking into account effective fluid phase theory and patchy saturation. We determine through sensitivity tests that the estimation of CO2 saturation is possible even when using only the P-wave velocity as input. After a characterization of rock frame properties based on log data prior to the CO2 injection at Sleipner, we apply our t...

Gender differences in substance use patterns and disorders among an Iranian patient sample receiving methadone maintenance treatment

Background The current prevalence rate of substance abuse and dependence, represents an increasing trend of substance abuse and dependence among women, and the results of epidemiology studies indicate that substance use patterns are different between men and women. This study aimed to determine gender differences in substance use patterns and disorders among the patients undergoing methadone maintenance treatment. Methods This cross-sectional study was conducted throughout a specified time bracket ranging from September 2012 through March 2013 in Methadone Maintenance Treatment (MMT) clinics of Mashhad, Iran. In this study, 140 men and 120 women were selected from among the patients referring to MMT clinics in Mashhad through purposeful sampling method. The sample units were assessed using a demographic information questionnaire and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID). The data were then analyzed by Chi Square test, Mann-Whitney U test, and Independent-samples t-test. SPSS software 16 was used to conduct statistical analyses with P values less than 0.05 regarded as significant. Results The results showed that men and women are significantly different from each other in terms of marital status (p=0.001), education (p=0.001), income (p=0.001), history of injection (p=0.002), imprisonment (p=0.001), and substance use abstention (p=0.023). It was also revealed that methamphetamine dependence (p=0.017) and simultaneous use of multiple substances (p=0.001) in the past 12 months were diagnosed, to a larger extent, in male participants than those in female participants. In addition, the diagnoses of nicotine dependence (p=0.001), cannabis abuse (p=0.001), heroin dependence (p=0.001), and substance abuse and alcohol dependence (p=0.001) during a lifetime were more frequently existing in males than those in females. Conclusion There are gender differences in substance use patterns and disorders that appear to be caused by the degree of access to substances and the impacts of cultural and social aspects on men and women in Iran.

Qualitative thallium urinary assays are almost as valuable as quantitative tests: implication for outpatient settings in low and middle income countries

Background Thallium (Tl), lead and steroid exposures were reported as a result of street drug consumption such as heroin and cocaine. Objective This study aimed to compare the values of qualitative and quantitative assays for detecting Tl as an adulterant in opioid-like compound drug users. Methods This case-control study was conducted throughout a specified time bracket ranging from May 2015 to November 2015 in Imam Reza Hospital, Mashhad, Iran. In general, urine thallium samples for 100 opioid overdosed subjects with a history of chronic opioid use and 50 non-drug users were studied. Qualitative 24 hours-urinary-thallium-level (QL) and quantitative 24 hours-urinary-thallium-level (QT) were conducted in both groups. Independent-samples t-test and Spearman’s Coefficient were applied for analytical purposes. SPSS software 16 was used to conduct statistical analyses with P values less than 0.05 regarded as significant. Results A total of 150 cases were studied. Raw opium users accounted for 66% of the cases followed by mixed (28%) and heroin users (6%). Mean (SD) QT level for QL was 26.8 (1) μg/L, while it was 2.3 μg/L (0.4 μg/L) for negative QL, which was far below QL positive cases (p=0.002). The qualitative test showed more accuracy at higher quantitative levels. In all cases, qualitative test was fully sensitive (100%), highly specific (89%) with a positive likelihood ratio (PLR) of 9.1 and a negative likelihood ratio (NLR) of 0. Conclusion These results suggest that qualitative assays could be used with confidence in assessing Tl exposure in drug users. Physicians may easily and confidently use Tl qualitative tests in rehabilitation centers, where toxicology laboratories may not be available.