American Petroleum Institute

DFT calculations clarify the mechanism of Pd/phosphine ligand/norbornene-catalyzed aryl chloride difunctionalization, rationalizing chemoselectivity and the roles of norbornene and XPhos ligand.

The adsorption behavior of amphiphilic Janus nanosheets at the oil-water interface plays a critical role in various interfacial applications, such as emulsification and enhanced oil recovery. This work investigates the adsorption kinetics of amphiphilic Janus nanosheets at the oil-water interface by using dynamic interfacial tension measurements and theoretical models. The adsorption process is analyzed in terms of diffusion-controlled kinetics and the influence of Ca2+ concentration on the behavior of amphiphilic Janus nanosheets at the interface. The results show that the adsorption process can be divided into three distinct stages: an initial rapid adsorption stage, a transition phase, and a later phase where the adsorption rate slows and the system approaches equilibrium. Furthermore, the presence of Ca2+ significantly enhances the diffusion of amphiphilic Janus nanosheets to the interface, thereby accelerating the adsorption process. The study also demonstrates that the maximum adsorption concentration of amphiphilic Janus nanosheets at the interface increases with Ca2+ concentration, suggesting that cationic electrolytes can enhance the interfacial adsorption capacity of amphiphilic Janus nanosheets. These findings provide valuable insights into the interfacial behavior of amphiphilic Janus nanosheets and highlight their potential for improving the performance of interfacial systems in various applications.

Objective: This study aimed to assess the prevalence, resistance patterns, and clinical predictors of MDROs in neurosurgical patients at a tertiary hospital in Oman. Materials and Methods: A retrospective analysis was conducted on 238 patients admitted to the neurosurgical and neurology departments at Khoula Hospital from January to December 2019. Data included demographics, clinical diagnoses, hospital stays, and antimicrobial resistance profiles. Statistical analyses, including Chi-square tests and logistic regression, identified predictors of prolonged hospital stay and high-risk patient groups. Results: Methicillin-resistant Staphylococcus aureus (MRSA, 54.2%) and carbapenem-resistant Enterobacteriaceae (CRE, 34.5%) were the most prevalent MDROs. Resistance was highest against b-lactams (95.4%), sulfonamides (95.4%), and quinolones (91.6%), with no resistance observed to oxazolidinones and lipopeptides. Multidrug resistance and CRE were significant predictors of prolonged length of stay (LOS) ( p < 0.001), and logistic regression identified a high-risk subgroup (10.1%) requiring focused interventions. The predominance of multi-source diagnostics (69%) underscored the importance of comprehensive testing in managing MDRO infections. Conclusion: The study highlights the substantial burden of MDROs in neurosurgical care in Oman, necessitating robust antimicrobial stewardship, targeted interventions, and ongoing surveillance. Future research should focus on multicenter studies to address the growing challenge of antimicrobial resistance.

Strict environmental regulations in Kazakhstan limit flaring during well cleanup, creating technical challenges for high-pressure wells under sour gas conditions (SPE-172339-MS). Conventional surface Well testing equipment could not meet these constraints, risking delays in production. This paper addresses these challenges through the deployment of ultra-high pressure zero flaring Surface Well Testing package for High Pressure well testing. It evaluates field application, operational feasibility, and implications for regulatory compliance in ultra-high-pressure environments. In comparison, global standards such as the European Union, ETS and US EPA, Subpart W also impose strict controls on flaring and greenhouse gas emissions. By aligning with these frameworks, Kazakhstan's regulatory stance demonstrates both local compliance and broader applicability to international sustainability practices. Karachaganak Petroleum Operating B.V. (KPO), operator of one of Kazakhstan's largest gas condensate fields, faced this challenge directly. Many of its wells on the low-pressure (LP) reservoir have wellhead pressures lower than the production system, and the presence of sour gas added further technical complexity. To address this, SLB and KPO developed the Zero-Flaring package with a surface pressure-boosting system to reinject multiphase well effluents into the production line. First deployed in 2018, it eliminated flaring during LP/HP cleanups. However, the package could only handle wells, which are connected to production line with flowing pressure up to 130barg. Beyond this injection pressure, there was a need to develop an ultra-high-pressure package (UHP) capable of well cleanup and injection at production line pressure exceeding 130barg. Flaring remained the only technically feasible industrial option for UHP well cleanup due to the unavailability of suitable surface equipment capable of cleaning and reinjecting in the production line at ultra high pressure (> 130barg). This approach conflicted with Kazakhstan's strict environmental regulations, which imposed severe flaring limits and threatened to delay or halt production from new UHP wells. To overcome this, Zero-Flaring Ultra High-Pressure (UHP) separation package - a groundbreaking solution enabling flaring-free cleanup of high-pressure wells was developed. The solution was successfully deployed in 2024 during three UHP cleanup operations at the Karachaganak field. The package performed safely and reliably under ultra-high-pressure and sour gas conditions, eliminating flaring and associated CO₂ emissions. It also enabled earlier production readiness, avoided regulatory noncompliance, and significantly reduced carbon footprint. This deployment marked the industry's first field use of a 220-bar-rated separator for surface well testing. The integration of high-specification pressure components and optimized flow assurance management contributed to the system's success under challenging well conditions. This paper discusses the design, execution, and performance of the technology and highlights its scalability for future HP developments requiring environmentally compliant, zero-flaring operations. This paper presents the first deployment of a 220barg rated surface separator used for zero-flaring UHP well cleanup an innovation that sets a new benchmark for ultra-high-pressure operations. It offers insights into equipment application under extremely sour gas conditions and operational workflows that ensure regulatory compliance. The paper provides scalable, field-proven solutions toward low-emission, sustainable energy production.

Working within the framework of Distributed Morphology, Arregi & Nevins (2012) proposed a modular architecture for the post-syntax in which metathesis follows impoverishment, and syntagmatic impoverishment (impoverishment conditioned by the features of more than one node) follows paradigmatic impoverishment (impoverishment conditioned by the features of only one node). Their analysis is supported by data from Basque. The morphological output of Taos (Kiowa-Tanoan) verbal agreement prefixes can be accounted for in this framework. However, not all divisions of labour are supported. While the claim that impoverishment precedes metathesis is upheld, the claim that paradigmatic rules of impoverishment universally precede syntagmatic ones is shown to be false. If the data of Taos is to be accounted for in this framework, I argue that it must be the case that paradigmatic and syntagmatic impoverishment operations can interleave.