A Novel In-Situ Generated Acid System on Carbonate Mineral Dissolution in Sandstone Reservoirs

Matrix acidizing has been used in oil and gas well stimulation for permeability and productivity enhancement purposes. HCl has been repeatedly used as a stand-alone stimulating fluid to decrease skin damage, create highly conductive wormholes in carbonate reservoirs, and stimulate sandstone reservoirs as a part of mud acid treatment. However, HCl in high-pressure/high-temperature (HP/HT) wells is a concern because of its rapid reactivity resulting in face dissolution, corrosion, and associated increased inhibition costs. This study investigates the effectiveness of a novel insitu-generated acid formulation with slower reaction and corrosion rates in stimulation operations in high temperature reservoirs. The new insitu-generated acid treatment was applied to stimulate two types of sandstone cores (Grey Berea and Bandera). X-Ray Diffraction (XRD) was performed on the sandstone cores to analyze their carbonate and clay content. Coreflood studies were conducted to investigate the impact of the treatment fluid on the permeability of outcrop and reservoir cores. Different flow rates of acid injection were set at 1 and 5 cm^3/min. The influence of temperature of 250 and 300˚F (121-148˚C) was investigated using the resulting effluent samples. These samples were analyzed using Inductively Coupled Plasma (ICP) for elemental analysis of key cations. Porosity profiles were determined before and after treatment using CT scans. Experiments were conducted on both the regular HCl acid system and the insitu- generated acid system for comparative purposes. Superior stimulation results were achieved at 121˚C (250) with the insitu-generated acid system. Although plugging problems caused by clay instability in reaction with HCl remains a major concern, positive stimulation results occurred in both Grey Berea and Bandera sandstone cores. This insitu-generated acid system efficiently removes carbonate and oxide minerals in HPHT sandstone reservoirs. No fines migration was observed with Grey Berea. A stimulation Kf/Ki (% increase) ranging from 10 to 30% was achieved with Grey Berea sandstone. The outcomes of this study will assist in a more cost-effective and efficient design of acid treatments with minimal jeopardy to the formation integrity

Menopausal symptoms: prediction of quality of marital relationship among couples

Objective. The current study determined the association between menopausal symptoms and marital quality of life, and explored the role of several demographic variables (education, occupation, and income) on these symptoms. Materials and Methods. The purposive sample included 180 married couples. Wives experiencing premenopause, perimenopause, and postmenopause 35 to 60 years old (M=45.21 & SD=7.47) were recruited from Islamabad and Rawalpindi, Pakistan. Two assessment instruments were used: Menopause Rating Scale- MRS for menopausal symptoms, and ENRICH Marital Satisfaction Scale- EMS for quality of marital relationship. Results. Wives’ quality of marital relationship was not significantly predicted by menopausal symptoms whereas husbands’ quality of marital relationship was significantly predicted by psychological (but not physical) symptoms of menopause. Also, several differences in menopausal symptoms and quality of marital relationship were found in relation to demographic variables. Conclusions. Clinicians should consider the relevance of psychological symptoms of menopause, and not just physical symptoms, in relationship assessment, a result that has research, practice, education and public health implications. Furthermore, possible cultural differences in the perception of menopausal effects should be addressed in greater depth

Shoreline Devastation of Hota Coast by Man-made Causes

AbstractThe impact of the removal of a river mouth bar as a measure against river mouth closure to the surrounding coasts was investigated, taking the Hota coast as an example. Also, on this coast, landfilling was extensively carried out to build a coastal road along the coastline, resulting in the narrowing of the natural sandy beach. These anthropogenic factors affected the overall shoreline on a pocket beach, devastating the natural coastal environment. We investigated the effects of these impacts using aerial photographs and field observations

Prevalence and risk factors associated with multi-drug resistant organisms (MDRO) carriage among pediatric patients at the time of admission in a tertiary care hospital of a developing country. A cross-sectional study

Background: The rise of Multidrug-resistant organisms (MDROs) poses a considerable burden on the healthcare systems, particularly in low-middle income countries like Pakistan. There is a scarcity of data on the carriage of MDRO particularly in the pediatrics population therefore, we aimed to determine MDRO carriage in pediatric patients at the time of admission to a tertiary care hospital in Karachi, Pakistan, and to identify the risk factors associated with it.Methods: A cross-sectional study conducted at the pediatric department of Aga Khan University Hospital (AKUH) from May to September 2019 on 347 children aged 1-18 years. For identification of MDRO (i.e., Extended Spectrum Beta-Lactamase (ESBL) producers, Carbapenem Resistant Enterobacteriaceae (CRE), Vancomycin Resistant Enterococci (VRE), Methicillin Resistant Staphylococcus aureus (MRSA), Multidrug-resistant (MDR) Acinetobacter species and MDR Pseudomonas aeruginosa), nasal swabs and rectal swabs or stool samples were cultured on specific media within 72 h of hospitalization. Data was collected on a predesigned structured questionnaire on demographics, prior use of antibiotics for \u3e 48 h in the last 6 months, history of vaccination in last 6 months, exposure to health care facility regardless of the time of exposure, ICU stay for \u3e 72 h, and about the prior use of medical devices (urinary catheter, central venous lines etc.) in last 1 year. Statistical analysis was performed by Standard statistical software.Results: Out of 347 participants, 237 (68.3%) were found to be MDRO carriers. Forty nine nasal swabs from 346 children (14.2%) showed growth of MRSA. The majority of the stool/rectal swabs (n = 222 of 322; 69%) collected were positive for MDRO. The most isolated species were ESBL Escherichia coli 174/222 (78.3%) followed by ESBL Enterobacter species 37/222 (16.7%) and ESBL Klebsiella pneumoniae 35/222 (15.8%). On univariate analysis, none of the risk factors showed statistically significant association with MDRO carriage.Conclusion: Overall, a high prevalence of MDRO carriage was identified among admitted pediatric patients. Implementation of systematic screening may help to identify true burden of MDROs carriage in the health care settings

QUALITY BY DESIGN (QBD) AS A TOOL FOR THE OPTIMIZATION OF INDOMETHACIN FREEZE-DRIED SUBLINGUAL TABLETS: IN VITRO AND IN VIVO EVALUATION

Objective: This study aims to prepare and optimize indomethacin freeze-dried sublingual tablets (IND-FDST) by utilizing a quality by design (QbD) approach to achieve rapid drug dissolution and simultaneously bypassing the GIT for better patient tolerability. Methods: A screening study was utilized to determine the most significant factors which the quality attributes, namely disintegration time and % friability. Then an optimization study was conducted using a full response surface design to determine the optimized formula by varying the amount of the matrix-forming polymer (gelatin) and super disintegrant (croscarmellose sodium (CCS)). The variables' effect on the % friability, disintegration time, wetting time, and amount of drug release after 10 min (%Q10) was studied. The optimized formula was tested for compatibility, morphology as well as stability studies under accelerated conditions in addition to the in vivo pharmacodynamics in rats. QbD was adopted by utilizing a screening study to identify the significant formulation factors followed by a response surface optimization study to determine the optimized IND-FDST formulation. Results: Optimized IND-FDST comprised of gelatin/CCS combination in a ratio of 1:1 possessed adequate %friability (0.73±0.03%), disintegration time (25.40±1.21 seconds), wetting time (3.49±0.68 seconds), and % Q10 (100.99±5.29%) as well as good stability under accelerated conditions. IND-FDST also showed significant inhibition of edema, tumour necrosis factor-alpha, and interleukin-6 release in vivo compared to the oral market product by 70%, 42%, and 65%, respectively. Conclusion: QbD presents a successful approach in the optimization of a successful IND-FDST formula that showed superior in vivo and in vitro characteristics

Sputnik V vaccine efficacy

Background and objective : Generally, protection against SARS-CoV-2 was assessed by the measurement of antibody titers against spike protein and receptor binding domain “RBD”. Many global efforts lead to development of several vaccines based on various strategies. The aim of the present study was to evaluate the efficacy of Sputnik V vaccine among Sari healthcare staff population, Iran. Methods : Seventy-nine health professional staffs that were vaccinated with two doses of Sputnik V vaccine were selected. The Immune response against spike and RBD proteins was evaluated by ELISA assays 3-4 weeks after second dose of vaccine injection. Results : The results showed the antibody titers were raised after vaccination. Data analysis has also demonstrated that the efficacy of vaccine was not related to age, gender and previous infection of SARS-CoV-2. Conclusion : Sputnik V vaccine can lead to a protective response against COVID-19 infection in high percentage of the population

Numerical Simulation on Sand Accumulation behind Artificial Reefs and Enhancement of Windblown Sand to Hinterland

Salients were formed in the lee of two artificial reefs (submerged breakwaters) constructed on Kimigahama Beach in Chiba Prefecture, Japan, owing to the wave-sheltering effect of the reefs, and then, a significant amount of fine sand was transported inland from the salients by wind action. In this study, not only shoreline changes after the installation of the two artificial reefs but also beach changes caused by windblown sand were predicted using a model, in which the BG model (a model for predicting three-dimensional beach changes due to waves based on Bagnold’s concept) is combined with a cellular automaton method. Reproduction calculation was carried out on the basis of field data. Beach changes after the artificial reefs were removed were also predicted and the effect of beach nourishment was investigated. It was concluded that landward sand transport by wind is accelerated when wave-sheltering structures such as an artificial reef are constructed on a coast composed of fine sand, and such an effect can be successfully predicted by using the present model

Beach erosion triggered by river mouth dredging as a measure against river mouth closure

On a pocket beach, the impact of the formation of the wave-shelter zone and the maintenance dredging of a river mouth reaches the entire pocket beach, and overall beach changes are triggered, devastating the natural environment. These topographic changes owing to anthropogenic factors took place at many coasts in Japan with the development of the coastal zone. We investigated this issue, taking the Haraoka and Tatara coasts in Chiba Prefecture as examples. Although several measures have been taken such as the sand back pass to mitigate the erosion, problems have not yet been solved. We discuss the reality and propose several measures to solve these problems

Topographic changes on Ajigura beach triggered by elongation of offshore breakwater

On Ajigaura Beach in Ibaraki Prefecture, Japan, severe beach erosion has occurred. Despite beach nourishment as a measure against beach erosion, wave run-up damage occurred in the south part of the beach where the foreshore was narrowed. The topographic changes of the beach were investigated on the basis of past aerial photographs and bathymetric survey data, and a numerical simulation using the BG model (a three-dimensional model for predicting beach changes based on Bagnold???s concept) was carried out. The measured and calculated results were in good agreement. It was concluded that the beach changes at Ajigaura Beach were triggered by northward longshore sand transport, which was induced by the wave-sheltering effect of the offshore breakwater

Essays on river mechanics

CER92-93-PYJ-5.Presented by the Graduate Students in CE 717 - River Mechanics (Spring 1993).Includes bibliographical references.April 1993