Solidification experiments were conducted for ternary Gd-Co-Ti immiscible alloys by copper mold casting. The impacts of the composition and cooling rate on the microstructure features and the ...properties were investigated. The samples with a composite microstructure were acquired, in which the subglobose TiCo-rich particles homogeneously distribute in the Gd matrix. The microhardness of Gd-Co-Ti alloys increases with the content of Co and Ti and the cooling rate during solidification. To describe the microstructure formation of Gd-Co-Ti immiscible alloys during rapid/sub-rapid solidification, a theoretical model was proposed, and it takes into consideration the comprehensive effects of the nucleation, diffusional growth and spatial motions of the TiCo-rich phase droplets. The solidification microstructure evolution was simulated. The numerical results are well consistent with the experimental data, which verifies the validity of the developed model. Calculations demonstrate that the nucleation of the TiCo-rich droplets only takes place in the liquid-liquid transformation stage, and no nucleation events of the TiCo-rich droplets occurs in the liquid-liquid-solid three-phase transformation stage. The number density (N) and maximum nucleation rate (Imax) of the TiCo-rich droplets/particles is exponentially associated with the cooling rate () of the alloy during the nucleation period of the TiCo-rich droplets. Besides, the Ostwald coarsening of TiCo-rich phase droplets can be ignored under the current cooling conditions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Annular electron beam which can be obtained by cylindrical ferroelectric cathode could achieve stable transmission and beam-wave conversion with high efficiency in high power microwave device. ...Besides, cylindrical ferroelectric cathode may obtain intense emission current and high density plasma due to the sample's large emission surface area.
This article makes a research of electron emission characteristic of cylindrical ferroelectric cathode. In experiment, lanthanum- doped lead zirconate titanate ceramic is introduced to manufacture thin cylinder. And then, in method of sintering silver, exterior wall is made into full electrode which is set as rear electrode, whereas, interior wall is made into grid electrode as inner electrode. High voltage pulse source used between rear to inner electrode and DC bias voltage used between graphite collector to inner electrode are set as trigger and extraction voltage, respectively.
The research puts emphasis on the change of electron emission intensity with trigger voltage and extraction voltage. Secondly, we analyze and discuss experiment phenomenon. Finally, we observe discharge in cylindrical cathode and record the section of emission current.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Dexmedetomidine, which is commonly used for procedural sedation and as adjunct to general anesthesia for ambulatory procedures, may affect patient discharge from the post-anesthesia care unit (PACU). ...We hypothesized that intraoperative dexmedetomidine use in ambulatory surgery is associated with delayed discharge from the PACU and that this is modified by surgical duration and anesthesia type.
Retrospective cohort study.
Academic medical center.
130,854 adult patients undergoing ambulatory surgery between 2008 and 2018.
Intraoperative administration of dexmedetomidine.
The primary outcome was PACU length of stay. In secondary and exploratory analyses, we examined dose-dependency, effect modification by duration of surgery and anesthesia type, effects of timing of dexmedetomidine administration, and PACU discharge delays.
Dexmedetomidine was associated with a prolonged PACU length of stay (adjusted absolute difference ADadj 15.0 min; 95%CI 12.7–17.3; p < 0.001). This effect was dose-dependent (p-for-trend < 0.001), magnified in surgeries of less than one hour (ADadj 20.7 min; 95%CI 16.7–24.7; p < 0.001) and in patients undergoing monitored anesthesia care compared to general anesthesia (ADadj 16.8 min; 95%CI 14.1–19.6; p < 0.001). The effect was more pronounced if dexmedetomidine was administered within the last 60 min of surgery (ADadj 18.7 min; 95%CI 15.7–21.7; p < 0.001). Dexmedetomidine was associated with discharge delays due to cardiovascular complications (ORadj 2.27; 95%CI 1.59–3.24; p < 0.001) and over-sedation (ORadj 1.28; 95%CI 1.11–1.48; p < 0.001). In patients who received dexmedetomidine (n = 2901), the use of bolus doses only versus the combination of bolus and infusions, magnified the effects on PACU length of stay (ADadj 29.5 min per μg/kg; 95%CI 17.3–41.8 versus 18.1 min per μg/kg; 95%CI 11.4–24.8; p < 0.001).
The intraoperative administration of dexmedetomidine was dose-dependently associated with a prolonged PACU length of stay. Clinicians should judiciously titrate dexmedetomidine, especially when using this long-acting drug for monitored anesthesia care for shorter procedures.
•Dexmedetomidine dose-dependently increases PACU length of stay.•The effect was magnified with monitored anesthesia care, and in patients undergoing procedures of shorter duration.•A dexmedetomidine bolus administered towards the end of surgery carries a magnified risk of prolonged PACU length of stay.•PACU discharge delays can in part be explained by over-sedation and cardiovascular complications.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Metal organic framework (MOF)-derivatives have a larger specific surface area, higher porosity, tunable pore size, higher conductivity, good stability, more exposed active species, etc., but few ...literature are reported about their application potential in micropollutant separation and removal. In view of this, a robust MOF derivative-based photocatalytic superhydrophobic membrane (D6/TiO2/MoS2/NiCo-NC/PVDF) was successfully fabricated for the first time through solvothermal synthesis and chemical modification, combined with a negative pressure-assisted loading approach. (1) The MoS2-doping strategy effectively avoided the collapse and coarsening of cauliflower-like MOFs during the calcination phase and simultaneously ensured the uniform distribution of metal particles in MOF-derived carbons. (2) The synergistic catalysis of the NiCo-MOF derivative, MoS2, and TiO2 enhanced the transfer efficiency of electrons and free radicals, achieving efficient in situ degradation of pesticides and pharmaceutical and personal care products. (3) The introduction of sodium alginate greatly improved the adhesion between the coating and polyvinylidene fluoride (PVDF) membrane and simultaneously enhanced the growth of MOFs through complexation. (4) The cauliflower-like MOF-derived carbon skeleton with higher surface areas and micronanoporosity combined with a heterogeneous MoS2 structure provided a large specific surface area and enough adsorption sites for various pollutants. High thermal calcination treatment greatly enhanced MOF growth rate, thus resulting in a flaky structure with high regularity and a large specific area. (5) The ultralow surface energy of interlaced siloxane molecules endowed the hybrid membrane with robust superhydrophobicity and superoleophilicity, always maintaining superhydrophobicity after long-time photodegradation. The final membrane achieved continuous emulsion separation and a photocatalytic self-cleaning property. The separation efficiency of the hybrid membrane for emulsions was still up to 97% after reuse for 120 cycles, and it could degrade 86.5% PRO, 90.1% ACE, 92.1% ASP, and 94.3% SMZ, respectively, with the initial concentration of 10 mg/L. The driving forces for oil–water separation and decontamination of the D6/TiO2/MoS2/NiCo-NC/PVDF membrane mainly involved the grasping forces of dodecamethylcyclohexasiloxane, capillary force of inner pores, electrostatic interaction, hydrogen bond interaction, partial p-π conjugation, van der Waals force, and lipophilicity.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
In geriatric patients scheduled for hip or knee surgery, neuraxial anesthesia is a safe and effective anesthesia method and may be a better option than general anesthesia. Unfortunately, establishing ...neuraxial anesthesia is not always easy in this group of patients. Anatomical abnormalities, such as spinal stenosis, scoliosis, and narrowed interspaces, contribute to the difficulties that anesthesiologists face while performing these procedures. The classic Taylor's approach targets the widest interspace, L5-S1, as the needle insertion site and accordingly has an increased success rate in difficult neuraxial anesthesia. As this technique historically relies solely on palpation, it might be difficult in patients with less prominent or distorted anatomic landmarks. Ultrasonography or fluoroscopy guidance may help to better target the epidural or subarachnoid space, but both have limitations due to equipment availability or provider expertise. The modified Taylor's approach we propose in this case report is based on preoperative lumbar x-ray interpretation when point-of-care image guidance cannot be performed. By measuring on the patient's preoperative lumbar x-ray, we successfully performed a modified Taylor's approach of spinal anesthesia on an elderly patient with severe scoliosis. She underwent open reduction and internal fixation (ORIF) of the left femur with satisfactory pain control and no complications.
The adoption of artificial intelligence (AI) algorithms is rapidly increasing in healthcare. Such algorithms may be shaped by various factors such as social determinants of health that can influence ...health outcomes. While AI algorithms have been proposed as a tool to expand the reach of quality healthcare to underserved communities and improve health equity, recent literature has raised concerns about the propagation of biases and healthcare disparities through implementation of these algorithms. Thus, it is critical to understand the sources of bias inherent in AI-based algorithms. This review aims to highlight the potential sources of bias within each step of developing AI algorithms in healthcare, starting from framing the problem, data collection, preprocessing, development, and validation, as well as their full implementation. For each of these steps, we also discuss strategies to mitigate the bias and disparities. A checklist was developed with recommendations for reducing bias during the development and implementation stages. It is important for developers and users of AI-based algorithms to keep these important considerations in mind to advance health equity for all populations. Author summary Though artificial intelligence (AI) algorithms were initially proposed as a means to improve healthcare and promote health equity, recent literature suggests that such algorithms are associated with bias and disparities. Therefore, we outline the various elements of potential bias in the development and implementation of AI algorithms and discuss strategies to mitigate them.
Notifiable disease surveillance in the United States is predominantly a passive process that is often limited by poor timeliness and low sensitivity. Interoperable tools are needed that interact more ...seamlessly with existing clinical and laboratory data to improve notifiable disease surveillance.
The Public Health Surveillance Knowledgebase (PHSkb) is a computer database designed to provide quick, easy access to domain knowledge regarding notifiable diseases and conditions in the United States. The database was developed using Protégé ontology and knowledgebase editing software. Data regarding the notifiable disease domain were collected via a comprehensive review of state health department websites and integrated with other information used to support the National Notifiable Diseases Surveillance System (NNDSS). Domain concepts were harmonized, wherever possible, to existing vocabulary standards. The knowledgebase can be used: 1) as the basis for a controlled vocabulary of reportable conditions needed for data aggregation in public health surveillance systems; 2) to provide queriable domain knowledge for public health surveillance partners; 3) to facilitate more automated case detection and surveillance decision support as a reusable component in an architecture for intelligent clinical, laboratory, and public health surveillance information systems.
The PHSkb provides an extensible, interoperable system architecture component to support notifiable disease surveillance. Further development and testing of this resource is needed.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Objective: Quantitative characterization of continuous pediatric drug infusions.
Background: The dynamics of drug delivery by continuous infusion to pediatric patients have not been ...systematically examined. This study extends previously described analytic models to propofol and remifentanil delivery, focusing on infants and toddlers. We postulated that infusion system dead volume, and drug and carrier flow rates, significantly influence drug delivery.
Methods: We studied effects of patient weight, infusion system dead volume, drug and carrier flow rates, along with drug stock concentration and dose, on propofol and remifentanil delivery to the circulation. We calculated the drug mass available for inadvertent bolus in the dead volume, the volume of fluid supplied by drug infusions, and model‐based estimates of the range of lag times to achieve a targeted steady‐state rate of drug delivery.
Results: The drug mass in the dead volume at steady state increased with dead volume size and drug dose. For infants, this drug mass could exceed 100% of commonly used loading doses. Predicted lag times to steady state depend on patient size, fluid flow rates, and the mixing behavior of the drug entering the main fluid pathway. Neonates have the longest lag times to achieve steady state. Fluid quantities delivered by drug infusions increase with drug flow rate and can represent a large fraction of estimated maintenance fluid requirements. Fluid delivery increases if stock drug concentrations are diluted. These relationships were qualitatively similar for propofol and remifentanil.
Conclusions: Traditional studies focus on drug disposition once a drug enters the circulation. Our analysis shows the potential importance of factors influencing drug delivery to the patient’s circulation, focusing on propofol and remifentanil administration to small patients. The drug mass available for inadvertent bolus residing in the reservoir of the dead volume at steady state may be large and clinically relevant. Lag times to achieve steady‐state delivery are long, depending on the infusion system’s architecture and fluid flow rates. By themselves, drug infusions can deliver significant fluid loads to children. These observations have practical and perhaps safety implications for infusions of drugs commonly administered to infants and children.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Fiberoptic intubation (FOI) is key in managing difficult airways. Good scope control increases efficiency and patient safety. Understanding the gap between novices and experts in scope control would ...help medical educators develop a feedback-based teaching approach for novices. We designed and used a checklist for evaluating the gap in fiberoptic scope control between novices and experts.
Twelve first-year anesthesiology residents (novice group) attended a lecture, followed by hands-on practice with a fiberoptic scope on a manikin. Five staff anesthesiologists (expert group) only did the hands-on practice. After practice, each participant was video-recorded while conducting an FOI on the manikin. Two senior anesthesiologists developed and used a 7-item checklist to assess the FOIs. Checklist scores and total times for FOIs were compared between groups using the Mann-Whitney
test. Internal consistency of the checklist items, interrater reliability, and the relationship between checklist score and total time for FOI were assessed with Cronbach alpha, Cohen kappa, and the Pearson correlation coefficient, respectively.
Experts had higher checklist scores than novices (
= .0016). The item with the lowest success rate for novices (50%) was keeping the scope straight. Novices spent more time on the FOI than experts (
= .0005). Cronbach alpha, Cohen kappa, and the Pearson correlation coefficient were 0.8699, 0.75, and -0.9454, respectively.
Our checklist was used to detect differences in fiberoptic scope control skills between novices and experts. With a video-based assessment method, it can be used to develop a feedback-based teaching method for fiberoptic scope control.
Background: There is paucity of data regarding prevalence and key harms of non-medical cannabis use in surgical patients. We investigated whether cannabis use in patients undergoing surgery or ...interventional procedures patients was associated with a higher degree of post-procedural healthcare utilisation. Methods: 210,639 adults undergoing non-cardiac surgery between January 2008 and June 2020 at an academic healthcare network in Massachusetts, USA, were included. The primary exposure was use of cannabis, differentiated by reported ongoing non-medical use, self-identified during structured, preoperative nursing/physician interviews, or diagnosis of cannabis use disorder based on International Classification of Diseases, 9th/10th Revision, diagnostic codes. The main outcome measure was the requirement of advanced post-procedural healthcare utilisation (unplanned intensive care unit admission, hospital re-admission or non-home discharge). Findings: 16,211 patients (7.7%) were identified as cannabis users. The prevalence of cannabis use increased from 4.9% in 2008 to 14.3% by 2020 (p < 0.001). Patients who consumed cannabis had higher rates of psychiatric comorbidities (25.3 versus 16.8%; p < 0.001) and concomitant non-tobacco substance abuse (30.2 versus 7.0%; p < 0.001). Compared to non-users, patients with a diagnosis of cannabis use disorder had higher odds of requiring advanced post-procedural healthcare utilisation after adjusting for patient characteristics, concomitant substance use and socioeconomic factors (aOR adjusted odds ratio 1.16; 95% CI 1.02–1.32). By contrast, patients with ongoing non-medical cannabis use had lower odds of advanced post-procedural healthcare utilisation (aOR 0.87; 95% CI 0.81–0.92, compared to non-users). Interpretation: One in seven patients undergoing surgery or interventional procedures in 2020 reported cannabis consumption. Differential effects on post-procedural healthcare utilisation were observed between patients with non-medical cannabis use and cannabis use disorder. Funding: This work was supported by an unrestricted philantropic grant from Jeff and Judy Buzen to Maximilian S. Schaefer.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
PDF
