Microscopic Characterization of Mineral Dissolution and Precipitation at Variable Salinity for Improved Oil Recovery in Carbonate Reservoirs

Aging of carbonate mineral surfaces in brines of variable salinity and crude oil leads to massive transformations of surface topography and chemical composition including the formation of mixed organic-inorganic interfacial layers. The response of these interfacial layers to variations in brine composition is responsible for local (chemical) wettability alteration and therefore becomes the main microscopic driver for improved oil recovery in low-salinity water flooding or SmartWater flooding. In this study, a new method was developed to directly visualize local nanoscale dissolution and (re)precipitation around the three-phase contact line on model calcite surfaces in the presence of crude oil and ambient brine upon aging. The sessile microscopic oil drops on calcite surfaces were exposed to brines of variable composition at room temperature (22 °C) and at elevated temperatures (95 °C) for up to 2 weeks. Brines ranged from hypersaline formation water to diluted high-salinity water, in part enriched with Mg2+ or SO42- ions. In situ optical and ex situ atomic force microscopy (AFM) imaging of the calcite surfaces was performed prior to and after aging, complemented by confocal Raman imaging. Optical images show that crude oil drops remained attached to the mineral surfaces throughout all aging procedures studied and displayed only occasional minor relaxations of their shape at elevated temperatures. Ex situ AFM images after calcite cleaning and drying displayed strong marks of the original droplet positions that appeared either as holes or as protruding mesas with respect to the surrounding surface level, with height differences up to several hundred nanometers. The sessile oil drops are thus found to protect the underlying calcite surface from both precipitation and dissolution, in overall agreement with the macroscopic calcite saturation of the brines. The qualitative trends are consistent for all conditions investigated, notwithstanding a higher degree of variability at elevated temperatures and upon preaging in oil-equilibrated formation water. In contrast to the calcite-brine interface that undergoes these massive transformations, the oil-calcite interface remains overall remarkably inert. Only at 95 °C does the occasional appearance of roundish rims accompanied by hillocks suggest the growth of water drops during aging, possibly via exchange across thin aqueous layers.</p

Prevalence and Associations of Type 2 Diabetes Risk and Sociodemographic Factors in Saudi Arabia: A Web-Based Cross-Sectional Survey Study

Type 2 diabetes mellitus (T2DM) is a chronic disease with ever-increasing prevalence worldwide. In our study, we evaluated the prevalence of the risk of developing T2DM in Saudi Arabia and investigated associations between that risk and various sociodemographic characteristics. To those ends, a web-based cross-sectional survey of Saudi nationals without diabetes, all enrolled using snowball sampling, was conducted from January 2021 to January 2022. The risk of developing T2DM was evaluated using a validated risk assessment questionnaire (ARABRISK), and associations of high ARABRISK scores and sociodemographic variables were explored in multivariable logistic regression modeling. Of the 4559 participants, 88.1% were 18 to 39 years old, and 67.2% held a college or university degree. High ARABRISK scores were observed in 7.5% of the sample. Residing in a midsize city versus a large city was associated with a lower ARABRISK risk score (p = 0.007), as were having private instead of governmental insurance (p = 0.005), and being unemployed versus employed (p &lt; 0.001). By contrast, being married (p &lt; 0.001), divorced or widowed (p &lt; 0.001), and/or retired (p &lt; 0.001) were each associated with a higher ARABRISK score. A large representative study is needed to calculate the risk of T2DM among Saudi nationals

International Nosocomial Infection Control Consortium report, data summary of 50 countries for 2010-2015: Device-associated module

•We report INICC device-associated module data of 50 countries from 2010-2015.•We collected prospective data from 861,284 patients in 703 ICUs for 3,506,562 days.•DA-HAI rates and bacterial resistance were higher in the INICC ICUs than in CDC-NHSN's.•Device utilization ratio in the INICC ICUs was similar to CDC-NHSN's. Background: We report the results of International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2010-December 2015 in 703 intensive care units (ICUs) in Latin America, Europe, Eastern Mediterranean, Southeast Asia, and Western Pacific. Methods: During the 6-year study period, using Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN) definitions for device-associated health care-associated infection (DA-HAI), we collected prospective data from 861,284 patients hospitalized in INICC hospital ICUs for an aggregate of 3,506,562 days. Results: Although device use in INICC ICUs was similar to that reported from CDC-NHSN ICUs, DA-HAI rates were higher in the INICC ICUs: in the INICC medical-surgical ICUs, the pooled rate of central line-associated bloodstream infection, 4.1 per 1,000 central line-days, was nearly 5-fold higher than the 0.8 per 1,000 central line-days reported from comparable US ICUs, the overall rate of ventilator-associated pneumonia was also higher, 13.1 versus 0.9 per 1,000 ventilator-days, as was the rate of catheter-associated urinary tract infection, 5.07 versus 1.7 per 1,000 catheter-days. From blood cultures samples, frequencies of resistance of Pseudomonas isolates to amikacin (29.87% vs 10%) and to imipenem (44.3% vs 26.1%), and of Klebsiella pneumoniae isolates to ceftazidime (73.2% vs 28.8%) and to imipenem (43.27% vs 12.8%) were also higher in the INICC ICUs compared with CDC-NHSN ICUs. Conclusions: Although DA-HAIs in INICC ICU patients continue to be higher than the rates reported in CDC-NSHN ICUs representing the developed world, we have observed a significant trend toward the reduction of DA-HAI rates in INICC ICUs as shown in each international report. It is INICC's main goal to continue facilitating education, training, and basic and cost-effective tools and resources, such as standardized forms and an online platform, to tackle this problem effectively and systematically