Oxygen Functionalities Research Articles

Nitrogen-doped graphene quantum dots synthesized by femtosecond laser ablation in liquid from laser induced graphene

In this work, graphene quantum dots (GQDs) were synthesized by femtosecond laser ablation in liquid using laser induced graphene as the carbon source. Nitrogen-doped graphene quantum dots (N-GQDs) were successfully synthesized by adding ammonia water to the graphene suspension. The GQDs/N-GQDs structure consist of a graphitic core with oxygen and nitrogen functionalities with particle size less than 10 nm, as demonstrated by x-ray photoelectron spectroscopy, Fourier infrared spectrometer spectroscopy, and transmission electron microscopy. The absorption peak, PL spectrum, and quantum yield of the N-GQDs were significantly enhanced compared with the undoped GQDs. Further, the possible mechanism of synthesis GQDs was discussed. Furthermore, the N-GQDs were used as a fluorescent probe for detection of Fe3+ ions. The N-GQDs may extend the application of graphene-based materials to bioimaging, sensor, and photoelectronic.

DFT study of NH3 adsorption on 2D monolayer MXenes (M2C, M = Cr, Fe) via oxygen functionalization: Suitable materials for gas sensors

This work deals with the kind of the interaction of NH3 molecules adsorbed on the MXene layers. The adsorption energies of NH3 on the surface of MXenes (M2C, M = Cr and Fe) and their oxygen-functionalized forms (O-MXenes or M2CO2) were calculated by using the density functional theory. DFT-D4 calculations have revealed that the on-top sites are initiated for adsorption of NH3 on M2C and M2CO2. For the reaction on Cr2CO2, the Ead is found to be −0.29 eV lower than Cr2C and also the same tendency was achieved in Fe2C and its O-terminated MXene. This suggests that the molecule will strongly adsorb on Cr2C than its O-terminated surface. Bader charge analysis in terms of the induced net charges on M2C MXenes suggests that electron density distribution between N of NH3 (negatively charged) and the Cr/Fe (positively charged) surface would play a key role in the adsorption. Furthermore, DOS calculations reveal that the electrical conducting behaviour and magnetic nature of MXenes make them suitable for gas sensors applications.

Natural bamboo-derived O-doped rocky electrocatalyst for high-efficiency electrochemical reduction of O2 to H2O2

The in-situ H2O2 electrosynthesis by two-electron oxygen reduction reaction employing renewable electricity is a promising alternative to traditional anthraquinone process due to its security, environmental friendliness and excellent cost effectiveness, which requires high-performance, cost-effective and environmental-friendly electrocatalysts. A bamboo-derived O-doped rocky electrocatalyst is developed by facile pyrolysis and acid treatment for high-efficiency electroreduction of O2 to H2O2. Three-dimensional interconnected hierarchical pores in rocky electrocatalysts expose abundant electroactive sites and facilitate mass transfer of reaction species. From the results of rotating ring-disk electrode test, a H2O2 selectivity up to 80% and superior electrocatalytic activity of the prepared electrocatalyst are achieved by surface oxygen functionalization induced by acid treatment. At the optimal catalyst loading of 2 mg cm−2, prominent H2O2 productivity of 1037 mmol gcatalyst−1h−1 with high current efficiency up to 74.1% is achieved at 30 mA cm−2 by air-breathing cathode. Higher H2O2 productivity (1525 mmol gcatalyst−1h−1) is yielded by further raising the current density to 50 mA cm−2. Moreover, the durability test of the cathode through ten consecutive runs demonstrates its great stability for electrocatalytic generation of H2O2. This work inspires the development of promising biomass-derived electrocatalysts for green and sustainable on-site H2O2 electrosynthesis.

TAXONOMÍA Y ECOLOGÍA DE LOS OLIGOCHAETA DE LA CUENCA DEL RÍO NEGRO Y OTROS REGISTROS PARA URUGUAY

The oligochaetes perform important functions of oxygenation of sediments where they live and in the movement of nutrients between water and sediment. They are usually used as bioindicators of water quality. In this article the genera found in the Rio Negro watershed are reported, describing their habitat preferences and tolerance to pollution. In addition, the species registered for Uruguay are listed both from bibliographic antecedents and from macroinvertebrate collections of the Limnology Section of Facultad de Ciencias. In 2015 and 2016 streams from the Rio Negro watershed were sampled with the objective to assess their water quality. In 30 streams 84 Naididae and 3 Lumbricidae were collected. Within Naididae four sub-families and 15 genera were found. A total of 39 species are reported including five for the first time for Uruguay.

Protonation of graphene oxide electrolyte during electrophoresis and effects on deposited film properties

Electrophoretic deposition (EPD) is widely used to prepare graphene oxide (GO) thin films. However, changes in the GO electrolyte under different EPD parameters and its impact on film properties are yet to be investigated. In this study, we report on GO solution separation into a clear supernatant and sediment through a voltage dependent sedimentation process. We relate the observed sedimentation to the dual effect of electrophoresis and water electrolysis at the electrode interface, which contributes to the protonation of GO at the anode. Current measurements during EPD indicate that the anodic deposition at low potentials is controlled by the concentration change of GO in the electrolyte. Conversely, at higher potentials, delamination of coating due to gas evolution has a significant influence on film growth. Spectroscopic and microscopic measurements reveal that the deposited layers at all potentials were GO. However, X-ray photoemission spectra (XPS) show reduced amounts of oxygen functionalities of films obtained at the early stages of deposition for lower potentials. This we relate to GO flake-size effects as opposed to an interface reduction reported in literature. These results present new insight into electrophoresis and associated surface and chemical structure of deposited GO. Additionally, it also provides a cost effective, scalable method of separating GO in bulk from solution during its synthesis and in applications where separation of the GO-based final product is required.

Retrospective Analysis of the Clinical Efficacy of Early Goal-Directed Therapy Combined with Meticulous Nursing Intervention in Patients with Posttraumatic Sepsis.

Objective To explore the intervention effect of early goal-directed therapy (EGDT) combined with meticulous nursing on patients with posttraumatic sepsis. Methods The data of 50 patients with posttraumatic sepsis undergoing EGDT in the emergency department of our hospital from January 2020 to December 2020 were retrospectively analyzed. According to different nursing methods, they were divided into control group (n = 25) with routine nursing measures and observation group (n = 25) with meticulous nursing measures. The application effect of the two nursing modes was scientifically evaluated. Results No statistical differences in general data were found between the two groups (P > 0.05). After 6 h of intervention, the circulatory function, oxygenation function, and renal function of both groups were better than those before intervention, and central venous pressure (CVP), mean arterial pressure (MAP), blood oxygen (PaO2), oxygenation index (PaO2/FiO2), central venous oxygen saturation (ScvO2), and urine volume in the observation group were notably higher than those in the control group (P < 0.05). The heart rate (HR), serum creatinine (SCr), and blood lactic acid in the observation group were notably lower than those in the control group (P < 0.05). The 28-day survival rate and quality of life after intervention in the observation group were notably higher than those in the control group, with obvious differences between the two groups (P < 0.05). Conclusion Meticulous nursing intervention for patients with posttraumatic sepsis undergoing EGDT can effectively improve the body's functional indexes, which is superior to the routine nursing in controlling the patients' condition, improving the survival rate and quality of life after intervention, and ensuring the clinical treatment effect. Therefore, it is worthy of promotion.

Total Synthesis of Dalesconol A by Pd(0)/Norbornene-Catalyzed Three-Fold Domino Reaction and Pd(II)-Catalyzed Trihydroxylation.

Herein, we describe a concise total synthesis of dalesconol A through a "polycyclization/oxidation" approach. In the polycyclization stage, a Pd(0)/NBE-catalyzed 3-fold domino reaction and a subsequent intramolecular Michael addition have been utilized for the one-step assembly of the heptacyclic molecular skeleton. In the late stage of oxidation state adjustments, a stepwise sequence including site-selective benzylic oxidation, Pd(II)-catalyzed oxime ether directed trihydroxylation, and desaturation has been adopted to introduce the oxygen functionalities and furnish the synthesis of dalesconol A. With the advantage of the late-stage amidation of three C-H bonds in a single step, the amino analogue of dalesconol A has also been obtained with high efficiency.

Total Synthesis of Euonymine and Euonyminol Octaacetate.

Euonymine (1) and euonyminol octaacetate (2) share the core structure of euonyminol (3), the most hydroxylated member of the dihydro-β-agarofuran family. In 2, eight of the nine hydroxy groups of 3 are acetylated, and 1 has six acetyl groups and a 14-membered bislactone comprising a pyridine dicarboxylic acid with two methyl groups. The different acylation patterns provide distinct biological activities: 1 and 2 display anti-HIV and P-glycoprotein inhibitory effects, respectively. The 11 contiguous stereocenters and 9 oxygen functionalities of the ABC-ring system of 1 and 2 represent a formidable challenge, which is further heightened by the macrocyclic structure of 1. Here we disclose an efficient synthetic strategy for enantioselective total synthesis of 1 and 2. Starting from (R)-glycerol acetonide, we constructed the B-ring by an Et3N-accelerated Diels-Alder reaction, the C-ring by intramolecular iodoetherification, and the A-ring by ring-closing olefin metathesis. The 10 stereocenters were installed through a series of substrate-controlled stereoselective C-C and C-O bond formations by exploiting the three-dimensional structures of judiciously designed substrates. These newly developed reaction sequences led to protected euonyminol 5, which served as a common intermediate for assembling 1 and 2. Global deprotection of 5 and subsequent acetylation produced 2. Alternatively, the discriminative protective groups of 5 allowed for site-selective bis-esterification to generate bislactone. Combining [3 + 2]-cycloaddition and reductive desulfurization introduced the last remaining stereocenters of the two methyl groups on the macrocycle. Finally, deprotection and acetylation gave rise to fully synthetic 1 for the first time.

The clinical effects of high-frequency oscillatory ventilation in the treatment of neonatal severe meconium aspiration syndrome complicated with severe acute respiratory distress syndrome

ObjectiveTo explore the efficacy and safety of high-frequency oscillatory ventilation (HFOV) in the treatment of severe meconium aspiration syndrome (MAS) complicated with severe acute respiratory distress syndrome (ARDS).MethodsA total of 65 infants with severe MAS complicated with severe ARDS were included in the study. The clinical efficacy of treatment for the HFOV group (n = 31) and the conventional mechanical ventilation (CMV) group (n = 34) was retrospectively analysed. The partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), PaO2/fraction of inspired oxygen (FiO2), and oxygen index values before and at 6, 12, 24, 48, and 72 h after mechanical ventilation, the mechanical ventilation time, oxygen inhalation time, incidence of complications, and outcomes of the two groups were compared.ResultsAt 6, 12, 24, and 48 h after mechanical ventilation, the PaO2 in the HFOV group was significantly higher than in the CMV group, while the PaCO2 in the HFOV group was significantly lower than in the CMV group (P < 0.05). At 6, 12, 24, 48, and 72 h after mechanical ventilation, PaO2/FiO2 in the HFOV group was significantly higher than in the CMV group, and the OI in the HFOV group was significantly lower than in the CMV group (P < 0.05). Mechanical ventilation time, oxygen inhalation time, and the incidence of air leakage were significantly lower in the HFOV than in the CMV group (P < 0.05).ConclusionsOverall, HFOV can effectively improve lung ventilation and oxygenation function, shorten ventilator treatment time, and reduce the incidence rate of air leakage for neonatal MAS, making it a safe and effective treatment option.

Feasibility and effectiveness of prone position ventilation technique for postoperative acute lung injury in infants with congenital heart disease: study protocol for a prospective randomized study

BackgroundProne position ventilation is a widely used lung protection ventilation strategy. The strategy is more convenient to implement in children compared to adults. Due to the precise mechanism of improving oxygenation function, development of pediatric prone ventilation technology has been largely focused on children with acute respiratory distress syndrome. There is a paucity of high-quality studies investigating the effects of prone position ventilation after pediatric cardiac surgery. The purpose of this study is to evaluate the feasibility and effectiveness of prone position ventilation in infants who develop postoperative acute lung injury after surgery for congenital heart disease.MethodsA single-center, randomized controlled trial of pediatric patients with acute lung injury after surgery for congenital heart disease who will receive prone position ventilation or usual care (control group). A total of 68 children will be enrolled according to the inclusion criteria. The main outcome measures will be lung compliance and oxygenation index. The secondary outcomes will be duration of mechanical ventilation, length of stay in cardiac intensive care unit, reintubation rate, and complication rate.DiscussionThis study will investigate the feasibility and effectiveness of prone position ventilation techniques in children who develop postoperative acute lung injury after surgery for congenital heart disease. The results may help inform strategies to improve airway management after surgery for congenital heart disease.Trial registrationClinicalTrials.gov NCT04607993. Initially registered on 29 October 2020.

Separation of propylene from propane and nitrogen by Ag(I)-doped nanoporous carbons obtained from hydrothermally treated lignin

Separation of propylene (C3H6) from propane (C3H8) is highly important to produce polymer (polypropylene)-grade C3H6. The separation of C3H6 from nitrogen (N2) is also industrially important to recover unreacted propylene from the polypropylene plant. Compared to the cryogenic separation that is usually employed to separate C3H6, an adsorption process is sustainable and inexpensive provided a suitable adsorbent is developed. Lignin is an inexpensive, sustainable, and natural precursor of porous carbons. In this work, we have hydrothermally treated lignin followed by its carbonization, activation and Ag(I) doping to synthesize the Ag(I)-functionalized microporous carbons. These carbons were characterized with pore textural properties, scanning electron microscopic imaging (SEM), EDX-mapping, and X-ray photoelectron spectroscopy (XPS). The Ag(I)-doped nanoporous carbons possessed the BET surface areas of 440–1146 m2/g and Ag(I) contents 1.5–5.9 at.%. The adsorption isotherms at 298 K and pressure upto 760 Torr suggested that all the adsorbents were selective to C3H6 compared to C3H8 and N2. Ideally adsorbed solution theory (IAST) was employed to calculate the selectivity of binary mixtures of 50/50 C3H6/C3H8 and 30/70 C3H6/N2 mixtures at 298 K. The selectivity of C3H6/C3H8 lies within 3–7 whereas the selectivity of C3H6/N2 lies within 259–2600 that is higher than that of a large number of adsorbents reported in the literature. It is observed that the carbon with a lower Ag(I) content is more selective to C3H6 that may be attributed to the competition between Ag(I) and oxygen functionalities. The fixed-bed dynamic breakthrough simulations suggested that C3H6 can be separated from N2 by all the carbons whereas C3H6 can be separated from C3H8 by the carbon with a lower Ag(I) content. The overall results suggested these carbons can potentially be used for C3H6 separations.

Synthetic Studies toward the Berkeleyacetal Core Architecture.

Berkeleyacetals are structurally complex natural products that have shown potent anti-inflammatory activity. The presence of a highly dense oxygen functionality and a polycyclic ring system presents significant synthetic challenges. Herein, we report an efficient strategy for the construction of the tetracyclic core system of berkeleyacetal. Our synthetic strategy features two cycloadditions ([4+2] and [5+2]) to forge the tetracyclic core and Achmatowicz rearrangement for the preparation of the cyclization substrates containing B and E rings.

Revealing the correlation between gas selectivity and semiconductor energy band structure derived from off-stoichiometric spinel CdGa2O4

Herein, the spinel CdGa2O4 and off-stoichiometric spinel CdGa2O4 (CdO-CdGa2O4) with 3D inverse opal spherical structure have been synthesized by the combination of ultrasonic spray pyrolysis technology and self-assembled hard-template method. The CdGa2O4, with band gap of 4.14 eV and baseline resistance of Mohm-level, exhibited excellent selectivity and high response to 1 ppm formaldehyde. On the other hand, the CdO-CdGa2O4 composites (Cd:Ga atom ratio = 1.2:2), with band gap of 2.46 eV and baseline resistance of kohm-level, exhibited best sensing performance to 1 ppm NO2 with negligibly low cross-responses (Rair/Rgas < 3.5) to any VOCs. Due to the semiconductor band gap is narrowed, and the conducting channel depending on the agglomeration of surface loaded CdO nanocrystals, the gas selectivity has been changed and the baseline resistance of off-stoichiometric spinel CdGa2O4 was reduced by many orders of magnitude. Meanwhile, the improvement of gas response can be attributed to ordered bimodal-porous structure, and the n-n heterojunctions induced decrease in work function and enhancement in chemisorbed oxygen. Accordingly, the proposed correlation between gas selectivity change and band gap modulation can open new route for solving the shortcoming of poor selectivity of metal oxide semiconductor gas sensor.

Quantitative Trait of Neutrophil Count Is Influenced By Variants in the Region of Gsdma and PSMD3-CSF3, aging, Cardiometabolic Comorbidities but Not By Chip

IntroductionHematopoiesis ensures lifelong oxygenation, immune and hemostatic functions through the production of billions of blood cells on a daily basis. However, little is known about the factors regulating and influencing this highly coordinated process and the resulting peripheral blood cell quantitative traits during the aging process. In this study, we investigated germline and acquired factors associated with blood cell counts in a cohort of normal aging individuals.MethodsDeterminants underlying blood cell trait variability were assessed in a cohort of 2996 related and unrelated women of French-Canadian ancestry aged 55 to 101 years. All participants answered a medical questionnaire and provided a blood sample for complete blood count with differential (GenS, Beckman Coulter) and DNA analysis. Potential hereditary variants of significance were assessed using a genome-wide association study (GWAS). Genotyping was performed according to the manufacturer's specifications on the Illumina Infinium Global Array v3-MD (Illumina, San Diego, CA). Variants with a completion rate of ≥98%, minor allele frequency >1% and imputation probability of ≥0.80 were retained. Genome-wide association testing was conducted with SAIGE_0.43.3 to account for the family-based design of our study. Genome-wide significance threshold was at 5x10 -8. Potential acquired factors of importance such as chronic comorbidities and clonal hematopoiesis of indeterminate potential (CHIP) were also sought. CHIP status was assessed with targeted next-generation sequencing of polymorphonuclear cells using the Ampliseq AML panel. Germline and acquired factors were then integrated in generalized linear mixed models to identify factors associated with blood cell indices in multivariate analysis and to characterize their relative contribution. Statistical analyses were conducted with R.ResultsMean age of study participants was 69.2 years (standard deviation 9.1 years). Mean values (and standard deviation) of blood cell indices were as follows: total white blood count (WBC) 6.43x10 9/L (1.63), absolute lymphocyte count 1.86x10 9/L (0.57), absolute monocyte count 0.46x10 9/L (0.16), absolute neutrophil count 3.93x10 9/L (1.29), hemoglobin 131.2 g/L (9.67), platelet count 249.2x10 9/L (57.6). Neutrophil and monocyte counts increased with age (b1 coefficient 0.02 (p-value 6.06E-08) and 0.004 (p-value 2.2E-16) respectively), while lymphocyte and platelet counts decreased with advancing age (b1 coefficient -0.01 (p-value 3.65E-07) and -0.29 (p-value 0.023) respectively). GWAS identified 13 variants in the region of GSDMA and PSMD3-CSF3 (chromosome 17) that met genome-wide requirements for WBC and neutrophil counts. Platelet count was significantly associated with a variant intronic to ARHGEF3 (chromosome 3). Among acquired factors, smoking was positively associated with neutrophil, monocyte, lymphocyte counts and hemoglobin levels. Distinctly, we document that cardiometabolic comorbidities (diabetes, coronary heart disease, hypertension and dyslipidemia) are associated with a statistically higher count of myeloid-derived cells (neutrophil count 4.1 vs 3.83 (95%CI 0.28-0.37, p-value <0.001), monocyte count 0.50 vs 0.45 (95%CI 0.02-0.05, p-value <0.001), and platelet count 259 vs 243 (95%CI 10-20, p-value <0.001). These results remained significant in multivariate analysis. In accordance with previous reports, CHIP, which was documented in 14% of the cohort, had no influence on blood counts.ConclusionWe document that individual variation in blood counts in individuals is influenced by several factors: (i) germline variants related to GSDMA and PSMD3-CSF3 contribute to white blood cell and neutrophil counts and a variant intronic to ARHGEF3 is influential in determining platelet counts; (ii) aging is associated with increasing levels of neutrophils and monocytes, and reduced lymphocyte and platelet counts, indicating a shift towards myelopoiesis; (iii) this myeloid-biased skewing is further increased among individuals with cardiometabolic comorbidities; (iv) CHIP does not contribute to the age-associated myeloid shift. These findings support that chronic age-related diseases may promote myelopoiesis and contribute to population variability in peripheral blood traits, possibly through a state of low-grade inflammation. [Display omitted] DisclosuresBusque: Novartis: Consultancy.

Investigating the Nucleation of AlOx and HfOx ALD on Polyimide: Influence of Plasma Activation

There is an increasing interest in atomic layer deposition (ALD) on polymers for the development of membranes, electronics, (3D) nanostructures and specially for the development of hermetic packaging of the new generation of flexible implantable micro-devices. This evolution demands a better understanding of the ALD nucleation process on polymers, which has not been reported in a visual way. Herein, a visual study of ALD nucleation on polymers is presented, based on the different dry etching speeds between polymers (fast) and metal oxides (slow). An etching process removes the polyimide with the nucleating ALD acting as a mask, making the nucleation features visible through secondary electron microscopy analyses. The nucleation of both Al2O3 and HfO2 on polyimide was investigated. Both materials followed an island-coalescence nucleation. First, local islands formed, progressively coalescing into filaments, which connected and formed meshes. These meshes evolved into porous layers that eventually grew to a full layer, marking the end of the nucleation. Cross-sections were analyzed, observing no sub-surface growth. This approach was used to evaluate the influence of plasma-activating polyimide on the nucleation. Plasma-induced oxygen functionalities provided additional surface reactive sites for the ALD precursors to adsorb and start the nucleation. The presented nucleation study proved to be a straightforward and simple way to evaluate ALD nucleation on polymers.

Enhanced ammonium removal and recovery from municipal wastewater by asymmetric CDI cell equipped with oxygen functionalized carbon electrode

Following the concept of sustainable development and circular economy, the Capacitive Deionization (CDI) was examined for the removal and recovery of ammonium (NH4+) ions from municipal wastewater towards prevention of eutrophication and obtaining a valuable component for fertilizers production. The electrosorption study was conducted in the symmetric CDI cell, composed of activated carbon (AC) electrodes, and an asymmetric CDI cell, equipped with oxygen functionalized AC (AC-ox) cathode. The asymmetric CDI cell was demonstrated the enhanced performance in terms of the removal efficiency towards ammonium ions (83%) and the related energy consumption (and 0.085 kWh/mmol NH4+), compared to the symmetric one with the following results: 30% removal of NH4+ ions and 0.215 kWh/mmol NH4+. The beneficial performance of the AC-ox electrode also has been observed in terms of NH4+ recovery: 20% recovered NH4+ ions, compared to 9% NH4+ recovered ions by AC pristine electrode. The presence of competitive ions hindered the electrosorption efficiency. Nevertheless, the time-dependent selectivity of the AC-ox electrode towards NH4+ ions was observed. The specific capacities of the symmetric and asymmetric cells at 5 mV/s were calculated to be 10.4 F/g and 18.3 F/g, respectively. Material characterization of AC before and after oxidation explained the enhanced CDI performance of the AC-ox electrode due to the increased hydrophilicity and additional oxygen functionalities on the electrode surface.

Mechanochemical activation of zero-valent iron on carbonized boron-doped graphene dots for enhanced sonochemical dyes removal

Boron-doped graphene dots (BGDs) were synthesized by a hydrothermal method using the disaccharide maltose as the carbon precursor and borax as the boron dopant. The precursors were heated to 500 °C for 5 h to obtain the carbonized BGDs (CBGDs). B doping was carried out to increase the surface area and improve the electron transfer reaction for quick and effective reactive oxygen species generation. BGDs and CBDGs showed different oxygen contents and functionalities, surface areas, morphologies, and zeta-potentials. Zero-valent iron (ZVI) was activated mechanochemically by surface passivation using BGDs and CBGDs under atmospheric conditions, and their dye removal performance via sonochemical degradation was evaluated. Owing to the greater oxygen functionality of BGDs, the ZVI@BGDs were fully decorated with ZVI, and less activation occurred that inhibited the sonochemical dye degradation properties of ZVI@BGDs. In contrast, a sheet-like structure and activation of ZVI on ZVI@CBGDs make it an active catalyst. The maximum surface area (413.82 m2/g) and high negative zeta potential (−38.25 mV) of CBGDs make it a good adsorbent. BGDs have a low surface area (20.78 m2/g), self-assembling structure, non-planer arrangement, and a twisted structure with interlocking spheres that disfavor π–π stacking between the dye and BGDs and make it non-adsorbent. The rapid generation of reactive oxygen species, the existence of iron with mixed-valence states, and the increase in surface area due to boron doping facilitate the electron transfer process to make the catalyst active and reusable even after 10 cycles.

Comparison of the Effects of Target-Controlled Propofol Infusion and General Anesthesia with Isoflurane on Postoperative Cognitive Functions in Controlled Hypotensive Anesthesia

Background/aim: We evaluated anesthesia depth, cerebral oxygenation and postoperative cognitive functions with NIRS and BIS monitoring and Mini-Mental State Examination (MMSE) score. Materials and methods: We studied 60 patients in Al –zahra teaching hospital over 18 years of age, with a preoperative MMSE test score of 23 and above. Hemodynamic parameters, BIS and bilateral NIRS values were recorded. The mean arterial pressure (MAP) value was kept between 55-65 mmHg. MMSE test was repeated 1 hour before and 24 hours postoperatively. Results: The extubation time was shorter. Aldrete recovery score and NIRS values were was higher and blood pressure and heart rate values were lower in the desflurane group. There was a moderate positive correlation between blood pressure values and NIRS in a certain part of the operation in the isoflurane group. In the propofol group, 5 patients had a more than 20% decrease in rSO 2 . In MMSE test score, there was no decrease in both groups in the preoperative and postoperative period. Conclusion: We think that, the isoflurane group be preferred as a priority with less remifentanil expenditure, lower blood pressure values, higher rSO 2 values, no 20% decrease in rSO 2 values, faster extubation, and statistically significant early recovery.Bispectral index, isoflurane, Controlled hypotension, Near-infrared spectroscopy, Postoperative cognitive dysfunction, Propofol, Mini mental scoreion DOI: 10.7176/JHMN/95-04 Publication date: November 30 th 2021

Facile electrochemical synthesis of triangle-shaped graphene nanoflakes and graphene quantum dots via surfactant-assisted and defect-induced mechanism

A facile and non-hazardous route for synthesis of triangle-shaped graphene nanoflakes and graphene quantum dots (GQDs) suspension via electrochemical exfoliation has been reported. In this work, a simple electrochemical technique was employed using pristine and heated graphite electrodes under the influence of anionic surfactant, sodium dodecylbenzene sulfonate (SDBS). The synthesized graphene nanoflakes and GQDs suspension were characterized using UV-visible spectroscopy, transmission electron microscope (TEM) and Raman Spectroscopy. The UV absorption spectra showed a bathochromic shift from the typical π → π* transition peak which due to the introduction of oxygen groups and/or functionalization of SDBS into the graphitic layers. Morphological analyses using TEM revealed the usage of heated graphite electrodes (600 °C at 5 min) produced a triangle-shaped graphene nanoflakes with an average size of ∼34 nm while the average size of the graphene nanoflakes obtained using the pristine graphite is ∼47 nm. A possible mechanism for the exfoliation of such morphology has been proposed. The graphene nanoflakes which have size less than 10 nm from both samples can be attributed to the presence of the GQDs. Raman analysis revealed ID/IG ratio of 0.223 and 0.203 for graphene nanoflakes electrochemically exfoliated from pristine and heated graphite respectively, which signifies a better quality and crystallinity and has low defects within the conjugated graphene backbone. The utilization of this electrochemical approach might expectantly pave the way towards the production of graphene nanoflakes with controlled morphology and low structural defects, which can be an efficient top-down process yet feasible for mass production.

Ortho-C-H Acetoxylation of Cubane Enabling Access to Cubane Analogues of Pharmaceutically Relevant Scaffolds.

A novel method of introducing an oxygen functionality into a cubane core was developed using a transition-metal-catalyzed directed acetoxylation methodology via C-H activation. The obtained compounds were derivatized into cubane analogues of pharmaceutically relevant structural motifs, namely, acetylsalicylic acid and coumarin motifs, which could potentially act as bioisosteres of these scaffolds.