Use Of Sac Research Articles

Precise Synthesis of Single‐Atom Catalysts for Boosting Next‐Generation Advanced Oxidation and Reduction Processes in Sustainable Energy Applications

AbstractSingle‐atom catalysts (SACs) demonstrate high selectivity, maximal atom utilization, and unique active site configurations, establishing them as a rapidly expanding research field. Understanding the intrinsic relationship between structure and catalytic performance is crucial for the effective use of SACs in catalysis. However, providing a clear explanation of the coordination environment and intrinsic structural regulation of SACs remains a significant challenge for next‐generation renewable energy materials, especially in advanced oxidation and reduction processes critical for sustainable energy applications. This comprehensive review offers an in‐depth overview of the current progress and design of SACs, with a specific focus on precise synthesis, structural control, and the relationship between structure and performance. Furthermore, we elucidate the reaction mechanisms of various catalytic systems and the selective methods used to precisely synthesize and enhance catalytic reactions in the sustainable energy sector. Finally, this review explores the complex challenges in investigating and developing SACs and offers a perspective on solutions in advanced oxidation and reduction technologies for future research to overcome these challenges and achieve practical applications.

Safety and efficacy of dual antiplatelet drugs for stent-assisted embolization on risk of stroke and prognosis in patients with ruptured intracranial aneurysms: One center results of CIAP-5 clinical trial.

Although stent-assisted coiling embolization (SAC) has been associated with a higher risk of ischemic and hemorrhagic complications, the use of SAC continues to rise for treating ruptured intracranial aneurysms (RIAs). This study aims to assess the safety and effectiveness of dual antiplatelet therapy (DAPT) in the context of RIAs. We conducted a retrospective analysis at a single center, involving patients with aneurysmal subarachnoid hemorrhage (aSAH) between May 1, 2017 and December 31, 2021. Patients were categorized into two groups: the SAC group and the non-SAC (NSC) group. Patients in the SAC group received DAPT. We compared modified Rankin Scale (mRS) score, along with hemorrhagic and ischemic complications, between the two groups to evaluate the safety and efficacy of DAPT for SAC. The study included a total of 541 patients, of whom 38 (7.0%) experienced hemorrhagic complications and 48 (8.9%) developed ischemic complications. Additionally, 99 (18.3%) and 84 (15.5%) had poor clinical outcomes at discharge and 6 months, respectively. However, no statistically significant differences were observed between the two groups. Our analysis revealed that aneurysm location in the posterior circulation was a significant risk factor for an unfavorable prognosis when antiplatelet drugs were used following SAC (p = 0.025). Administering antiplatelet drugs after SAC for RIAs has demonstrated both safety and effectiveness. However, caution should be exercised when considering this treatment strategy for RIAs located in the posterior circulation due to the potentially elevated risk.

Engineering Photoelectrochemical Detection by Combining Nanozyme and Oxygen Reduction

Efficient photoelectrochemical (PEC) detection requires a deep understanding of the processes involved in generating, separating, and reacting photoinduced carriers at interfaces. However, slow interfacial reactions and the need for appropriate photoactive layers pose significant challenges to constructing advanced PEC platforms. In this study, platinum single-atom catalysts (Pt SACs) were integrated onto semiconductor surfaces as a proof of concept, amplifying PEC signals by boosting oxygen reduction reactions. Pt SACs were also shown to exhibit efficient peroxidase-like activity, depressing PEC signals through Pt SACs-mediated enzymatic precipitation reactions. By utilizing the oxygen reduction and peroxidase-like activity of Pt SACs, a robust PEC sensing platform was successfully constructed for the sensitive detection of SARS-CoV-2. This research provides valuable insights into the use of SACs for sensitive PEC analysis. Figure 1

Coaxially grafting conjugated microporous polymers containing single-atom cobalt catalysts to carbon nanotubes enhances sulfur cathode reaction kinetics

Conjugated microporous polymers (CMPs) hold great potential for use in energy related applications due to their extended π-conjugated structures, tunable pore sizes, and modular molecular functionalities. Herein, we report a novel composite material (labeled as Co-CMP-MWNTs) that consists of a CMP containing Co single-atom catalysts (Co SACs) and being coaxially grafted to multi-walled carbon nanotubes (MWNTs), and show that the material synergistically promotes the cathode reaction kinetics in lithium−sulfur (Li−S) batteries. The Co-CMP-MWNTs are synthesized by coupling 2,4,6-tris(4-ethynylphenyl)-1,3,5-triazine to a dibromobipyridine-Co complex in the presence of bromopyrimidinyl-functionalized MWNTs. The composite features a conductive MWNT-based core and a CMP-based shell that contains nitrogen as well as Co. Cs-corrected high-resolution transmission electron microscopy and X-ray absorption near-edge structure (XANES) spectroscopy reveal that the Co species exist as single atoms. Additional XANES data coupled with density functional theory calculations elucidate the adsorption interactions formed between the Co SACs and various sulfur species as well as their electrocatalytic effects. Li−S cells prepared using Co-CMP-MWNTs as a cathode host material exhibit excellent performance in terms of specific capacity (1485 mA h g−1 at 0.1 C), rate capability (602 mA h g−1 at 3 C), and cycling stability (510 mA h g−1 at 0.5 C after 1000 cycles, which corresponds to a capacity decay of 0.050% per cycle). Collectively, the results demonstrate that SACs can be prepared under benign conditions and used to enhance sulfur cathode reaction kinetics. The methodology described may be extended to enable the use of SACs in other contemporary energy conversion technologies.

Complex subcostal eventration: use of sac and prosthesis in resolution

Complex subcostal eventration: use of sac and prosthesis in resolution

SAC Assessment Tool in Implant Dentistry: Evaluation of the Agreement Level Between Users.

The SAC Assessment Tool is a clinical decision support system based on the foundations of the SAC Classification System in Implant Dentistry developed by the International Team for Implantology in 2009. It objectively classifies a patient's rehabilitation with dental implants as straightforward, advanced, or complex, from both a surgical and restorative perspective. The aim of this research was to test the agreement between observers with different qualification levels and clinical experience when using this clinical decision support system as a method that mitigates risk. A total of 30 patients were randomly selected from clinical records, and diagnostic casts, intraoral and extraoral images, and panoramic radiographs were obtained. All data were analyzed with and without the SAC Assessment Tool by a dentist with advanced training and clinical experience in implant dentistry (control dentist) and compared with three colleagues (dentists 1, 2, and 3) with fewer qualifications and less clinical experience. All data were analyzed using statistical agreement tests (Fless kappa), interclass correlation, and agreement rate. The level of significance (α) was set at .05. All patients included in this research presented 104 edentulous areas, which were subjected to surgical evaluation for possible placement of dental implants. Concerning the degree of risk evaluation for dental implant treatment, the results of this study found that the agreement rate of the control dentist without SAC and control dentist with SAC was excellent (81.7%); the agreement rate of the control dentist and dentists 1, 2, and 3 with the use of SAC was satisfactory (67.3% to 76.0%); the variable that presented a lower agreement rate (34.6%) was the comparison between dentists 1, 2, and 3 without use of the SAC Assessment Tool. The SAC classification seems to be a useful tool to assist dentists with less experience in implant dentistry with defining the complexity of the treatment and hence with patient selection. It helps in the collection and homogenization of important clinical data to assess the risk of implant-based rehabilitations, thus contributing to an increase in the agreement rate.

Migration and sac expansion as modes of midterm therapeutic failure after endovascular aneurysm sealing

BackgroundEndovascular aneurysm sealing (EVAS) is a disruptive technology to treat abdominal aortic aneurysm (AAA). The use of sac filling rather than endograft fixation was designed to treat aortic aneurysms in a wide range of morphologic appearances and to reduce endoleaks. There are few data reporting outcomes beyond postoperative follow-up. This study reports outcomes up to 5 years for Nellix (Endologix, Irvine, Calif) EVAS. MethodsData were prospectively collected for EVAS patients from the time of adoption of EVAS in 2013. All patients treated with the Nellix device are included in this study, and as such, it reports on infrarenal, ruptured, and iliac aneurysms as well as the Nellix-in-Nellix application. Juxtarenal and suprarenal aneurysms were treated using the EVAS system with parallel grafts into the visceral vessels and are included. Therapeutic failure, a composite outcome of migration, sac expansion >5 mm, type Ia and type Ib endoleak, and secondary aortic rupture, was the primary outcome along with all-cause mortality, aneurysm-related mortality, and reintervention rates. ResultsThere were 295 EVAS cases undertaken between March 2013 and July 2018. Indications for treatment were infrarenal (n = 185), juxtarenal and suprarenal (n = 73), ruptured (n = 18), and iliac (n = 13) aneurysms. There were 15 reinterventions using the Nellix-in-Nellix application. In some cases, EVAS was used to salvage failing endovascular or open aneurysm repairs. Median follow-up was 2.42 years (interquartile range, 1.07-3.57 years).Therapeutic failure was observed in 98 of the 295 cases (33.2%) overall and exceeded 50% in some subgroups. In 71 cases (24.1%), reintervention was performed, with reasons for no reintervention being mainly physiologic. Complications leading to therapeutic failure were most commonly seen beyond 2 years of follow-up. There were 15 secondary ruptures (5.36%), and 9 EVAS devices required explantation either electively or for aortic rupture. ConclusionsEVAS with the Nellix device has not met expectations, and early encouraging results have been eroded. The incidence of therapeutic failure has been high, occurring 2 years and beyond after implantation. The Nellix system has been voluntarily recalled by Endologix, and the CE mark has subsequently been suspended. The adoption of EVAS as a disruptive technology highlights the need for cautious adoption of novel technologies and the strict governance around such arrangements.

The Impact of Self-Access Centres in Fostering Confidence, Motivation and Autonomy to Develop Language Skills

This Paper investigates the relation between studying in Self-Access centres and learners’ confidence, motivation and autonomous learning. The study based on three questions: (a) To what extent autonomous learning motivates students/users of SAC? (b) Is the use of SAC reinforcing students’ confidence? (c) To what extent using SAC help in developing the students; learning skills? A questionnaire conducted to show learners; attitudes towards using SAC. The data was statistically analysed. The most important result revealed that the learners felt more confident and motivated after using SAC. Besides, there were a noticeable change in their language understanding and remarkable improvement in their language skills.

State-based predictions with self-correction on Enterprise Desktop Grid environments

The abundant computing resources in current organizations provide new opportunities for executing parallel scientific applications and using resources. The Enterprise Desktop Grid Computing (EDGC) paradigm addresses the potential for harvesting the idle computing resources of an organization’s desktop PCs to support the execution of the company’s large-scale applications. In these environments, the accuracy of response-time predictions is essential for effective metascheduling that maximizes resource usage without harming the performance of the parallel and local applications. However, this accuracy is a major challenge due to the heterogeneity and non-dedicated nature of EDGC resources. In this paper, two new prediction techniques are presented based on the state of resources. A thorough analysis by linear regression demonstrated that the proposed techniques capture the real behavior of the parallel applications better than other common techniques in the literature. Moreover, it is possible to reduce deviations with a proper modeling of prediction errors, and thus, a Self-adjustable Correction method (SAC) for detecting and correcting the prediction deviations was proposed with the ability to adapt to the changes in load conditions. An extensive evaluation in a real environment was conducted to validate the SAC method. The results show that the use of SAC increases the accuracy of response-time predictions by 35%. The cost of predictions with self-correction and its accuracy in a real environment was analyzed using a combination of the proposed techniques. The results demonstrate that the cost of predictions is negligible and the combined use of the prediction techniques is preferable.

College Students’ Use of the Computer and Network-based Self-Access Centre and Their English Learning Achievement

This study examined how Chinese College students’ use of the computer-based Self-Access Language Learning Centre affects their English learning. The study investigated whether the gender difference influences students’ perceptions of the Self-Access Centre and whether students’ use of the Centre helps improve their English learning. Data was collected through questionnaires and a survey given to 120 sophomores at a technology university in Hubei, China. The data showed 1) no significant relationship between gender and students’ perceptions of the use of SAC and 2) significant correlations between students’ satisfaction of the SAC environment and their Oral English improvement, between students’ beliefs of learning better in the SAC and the improvement in their listening ability. Based on the research results, it was suggested that to provide a relaxed and material-rich environment and to improve learners’ autonomous learning can help improve the effectiveness of students’ use of the SAC.

Esterification via saccharine mediated silica solid catalyst

Saccharine (Sac) was immobilized onto rice husk ash (RHA) silica via 3-(chloropropyl)triethoxysilane (CPTES) to form a new catalyst, RHAC-Sac. The saccharine loading on the silica was found to be ca. 82%. The 29Si MAS NMR showed the presence of T 2, T 3, Q 3 and Q 4 silicon centers. The 13C MAS NMR showed that RHAC-Sac had three chemical shifts consistent with the three carbon atoms of the propyl group and a series of chemical shifts consistent with the presence of the aromatic ring. RHAC-Sac had a specific surface area of 250 m 2 g −1 and a narrow average pore size of 3.28 nm. RHAC-Sac was used as a catalyst in the esterification reaction between ethyl alcohol and acetic acid. A 66% conversion was achieved at 85 °C with 100% selectivity for the ester. The stoichiometric composition of acid:alcohol = 1:1 was found to give the highest conversion. The use of Sac as a homogeneous catalyst also gave similar results to that of RHAC-Sac. RHAC-Sac could be reused several times by regenerating at 150 °C.

Evaluation of immunoregulatory T cell activity in common variable immunodeficiency by using <i>Staphylococcus aureus</i> Cowan 1

Pokeweed mitogen (PWM) is widely used to induce immunoglobulin production of PBL. Since PWM predominantly stimulates suppressor T cells, it is sometimes impossible to evaluate correctly the function of B cells or helper T cells. It is known that Staphylococcus aureus Cowan 1 (SAC) induces T cell-independent proliferation of B cells and T cell-dependent differentiation of B cells. To study the activation of T cells stimulated by SAC, two surface antigens (T4, T8 and Tac) were determined simultaneously by indirect immunofluorescence. By this method, SAC was demonstrated predominantly to activate the T4+ T cells, but not the T8+ T cell subset.Suppressor T cells are believed to be involved in the pathogenesis of some cases of common variable immunodeficiency (CVID). Such cells suppress PWM induced Ig production in coculture of normal and patient lymphocytes. Peripheral blood lymphocytes (PBL) and T cells of two patients with CVID and a patient with agammaglobulinemia were shown to suppress PWM induced Ig production of control PBL. However T cells of these three patients showed normal helper activity in SAC induced Ig production. The data indicate that the parallel use of SAC and PWM is always needed for studying the mechanisms responsible for altered immunoregulation in patients with hypogammaglobulinemia.

The use of dietary-restricted rat intestine for active transport studies.

1. The effect of dietary restriction (sufficient to produce a loss of about 32% of initial body weight) on intestinal active transport has been studied in the rat by the use of sacs of everted mid-small intestine. Eight D-sugars, four L-sugars and two D-amino acids were employed.2. Dietary restriction enhanced the normally occurring active transport of D-galactose, 3-O-methyl-D-glucose and D-methionine. In addition, sacs of dietary-restricted small intestine were able to concentrate in the serosal fluid D-fucose, D-xylose and D-histidine, which sacs of normal rat intestine could not do. The final (1 hr) serosal/mucosal concentration ratios produced for these actively transported substances were independent of net water movement.3. Sugars which were not concentrated in the serosal fluid of sacs of fully fed or dietary-restricted intestine were D-arabinose, D-fructose, D-glucosamine, D-mannose, L-arabinose, L-fucose, L-sorbose and L-xylose.4. The characteristics of D-fucose and D-xylose active transport suggest that they are transported by the mechanism which actively transports D-glucose. The comparatively low content of D-glucose in dietary-restricted intestine, compared with fully fed intestine, may be part of the explanation for observable active transport of D-fucose and D-xylose by dietary-restricted sacs.5. Thinning of the intestinal wall is believed not to be the cause of the enhanced active transport found during dietary restriction.6. The results show that dietary-restricted rat small intestine may, at times, be more useful than fully fed rat small intestine in the study of intestinal active transport.

Active transport of l‐glucose by isolated small intestine of the dietary‐restricted rat

1. The effect of semistarvation and complete starvation (sufficient to produce a loss of about 32 and 25% respectively of initial body weight) on the active transport of L-glucose has been studied by the use of sacs of everted mid-small intestine of rats. The animals were allowed free access to water.2. Sacs from animals on a restricted diet transported L-glucose against its concentration gradient, but sacs from fully fed rats did not. Even when sacs from fully fed rats were distended sufficiently to cause them to lose serosal volume, the L-glucose concentration in the final serosal fluid was never greater than that in the final mucosal fluid.3. The L-glucose active transport was independent of net water movement, needed oxygen, was not demonstrable at 27 degrees C, and required Na ions at a concentration of 83 mM or greater. It could be completely inhibited by 10(-6)M phlorrhizin, or 10 mM L-histidine, or 1.39 mM D-glucose. Phlorrhizin at a concentration of 10(-8)M reduced, but did not prevent, L-glucose active transport.4. It seems probable that L-glucose active transport is mediated by the mechanism that actively transports D-glucose.5. Un-incubated mid-small intestine of fully fed rats contained 37.8 mg D-glucose/100 g wet wt. of tissue, whereas semistarved intestine had only 10.8 mg D-glucose/100 g. The lack of demonstrable active transport of L-glucose by normal intestine may possibly have been caused, at least in part, by inhibition of the process by endogenous D-glucose.6. There appeared to be no metabolism of L-glucose by rat intestine, nor conversion to the D-form.7. The hypothesis that sugars require the D-pyranose ring structure for active absorption is no longer tenable.

Studies on the active transport of D-glucose and L-histidine by rats and golden hamsters fed on a penicillin-enriched diet.

1. The effect of a penicillin-enriched diet (100 mg or 1000 mg penicillin-G/kg food) on the active transport of D-glucose and L-histidine has been investigated by the use of sacs of everted small intestine of normal young adult rats and golden hamsters. The antibiotic was given for up to several weeks.2. The penicillin made no difference to the final concentration gradients of D-glucose or L-histidine achieved by rat small intestine, although with the hamster these appeared somewhat improved. Water entry into the serosal fluid remained unchanged.3. The lengths and the dry weights of the small intestines of both species were not altered by the dietary regimen.

Further studies on intestinal active transport during semistarvation.

1. The effect of semistarvation (sufficient to produce a loss of 18-28% of initial body weight) on the active transport of D-glucose and L-histidine by the rat, the guinea-pig and the golden hamster has been investigated by the use of sacs of everted small intestine (from upper jejunum to lower ileum).2. In the rat and the guinea-pig the dietary restriction resulted in increased active transport in all regions of the small intestine. In contrast, it caused no alteration in active transport in the hamster.3. The response in the rat was most impressive in the middle-to-lower ileum during D-glucose uptake. Whereas normal sacs from this area appeared unable to move the sugar against its concentration gradient, sacs from semistarved rats did so quite well.4. Although there was a considerable loss (24-29%) of intestinal dry weight in all three species when the food intake was reduced, shortening of the small intestine was not detectable in the guinea-pig or the hamster and was present to only a minor extent in the rat.5. Evidence is presented indicating that the enhanced active transport is not merely a reflexion of the thinning of the intestinal wall and that it occurs during complete as well as in partial starvation.

The use of sacs of everted small intestine for the study of the transference of substances from the mucosal to the serosal surface.

The use of sacs of everted small intestine for the study of the transference of substances from the mucosal to the serosal surface.