Glycosaminoglycans and collagen fibril distribution at various depths of the corneal stroma of normal and CXL treated rats.

Corneal collagen cross-linking (CXL) is widely used to treat keratoconus and ecstatic corneal disorders. The present studies were carried out to investigate the distribution of glycosaminoglycans (GAGs) and collagen fibril (CF) at different depths of the normal and CXL treated corneal stroma of four week old rats 7 days after standard CXL application. Ten Wistar rats' corneas were used for the study. The epithelium of the cornea from the left eye of each rat was removed and treated with standard CXL application using riboflavin and Ultraviolet-A (UVA) (3 mW/cm2 for 30 min). The cornea from the right eye was used as the control cornea. The cornea was removed from the eye and processed for transmission electron microscopy. A bottom mounted Quemesa camera was used to capture digital images and these images were analysed using iTEM software. In the control cornea, the GAGs area size was not significantly different in the anterior, middle, and posterior stroma. In the CXL treated rats the GAGs area size gradually increased from the anterior to the posterior stroma whereas the spacing between the GAGs gradually decreased. There were very large GAGs present in the posterior stroma of the CXL treated rats. When comparing the control and CXL cornea, the GAGs area in the CXL cornea was significantly higher and inter-GAGs-spacing was smaller than in the control cornea. In the control cornea, the collagen fibrils diameter was higher in the anterior stroma and lowest in the posterior stroma. In the CXL treated cornea, the CF diameter and the interfibrillar spacing gradually decreased from the anterior to the posterior stroma. On comparison between the control and the CXL treated cornea, the interfibrillar spacing was significantly smaller in the CXL treated cornea than the control cornea in the anterior, middle, and posterior stroma but there was no difference in the diameter. The CXL treatment significantly increased the GAGs area and decreased the inter-GAGs-spacing, and inter-CF-spacing. This could be due to the gradual decline in the availability of riboflavin, UVA, and oxygen in the middle and posterior stroma. Further studies are required to investigate the role of keratan sulphate and chondroitin sulphate by using monoclonal antibodies with immunogold technique.

Exploring Si-centered phthalocyanine as a single atom catalyst for N2O reduction: a DFT study.

To remove the greenhouse gas N2O from the environment, recently, researchers have taken great interest in single-atom catalysts (SACs). In this study, we investigated various reaction pathways and barrier energies for the N2O reduction process onto Si-coordinated phthalocyanine (Si@PthC) employing density functional theory. The outcomes validate that Si decoration in PthC is energetically stable while the corresponding electronic properties show that the Si atom acts as the reactive site for catalytic activity. The N2O molecule exhibits spontaneous dissociation over the catalyst surface from the O-end with -4.01 eV dissociation energy. Meanwhile, N2O dissociation via the N-end involves chemisorption onto the Si@PthC surface with an adsorption energy (Ead) of -1.16 eV, and the dissociation needs an energy barrier of 0.51 eV. The bond distances and negative adsorption energies (-1.11 and -2.40 eV) evince that CO and O2 species chemisorbed onto the Si@PthC surface. However, these energies are smaller than the N2O dissociation energy, which demonstrates that the presence of CO and O2 molecules cannot interrupt the N2O reduction process. Additionally, the CO + O* → CO2 reaction was executed for catalyst recovery, and the reaction proceeds very quickly on the Si@PthC catalyst, with a very small energy barrier (0.37 eV), indicating the excellent catalytic reactivity of the studied catalyst. These results propose that the designed catalyst can be valuable in the progress of novel noble metal-free catalysts for the elimination of harmful N2O from the environment.

Complete and incomplete bridge type double-orifice mitral valve: Diagnosis and characterization with three-dimensional transesophageal echocardiography.

Double orifice mitral valve is a rare congenital anomaly that is often associated with other congenital cardiac abnormalities. Patients may present with valvular dysfunction or may be asymptomatic and have an incidental diagnosis of double outlet mitral valve. Whether symptoms due to this pathology are present or not it is important to accurately characterize this lesion. Three-dimensional imaging is a powerful diagnostic modality for diagnosing and characterizing lesions such as this as highlighted in this case image series where we describe how three-dimensional transesophageal echocardiography was utilized to characterize both complete and incomplete bridge type double orifice mitral valve.

Challenges in the management of idiopathic pulmonary fibrosis from a low- and middle-income country.

Idiopathic pulmonary fibrosis (IPF) is the most common progressive form of interstitial lung disease (ILD) that leads to gradual deterioration of lung function and ultimately death. Data from low- and middle-income countries (LMIC) on IPF is scarce. In this communication, we report the challenges encountered in managing IPF from Pakistan's largest tertiary care centre. A total of 108 patients with IPF were evaluated at the Aga Khan University Hospital in Karachi, Pakistan from January 2017 to March 2020. A significant concern was that most patients with IPF presented late during their disease. A bigger challenge encountered in clinical practice was the cost and nonavailability of antifibrotic therapy in the country until mid-2020. Successfully addressing these limitations, it is anticipated that better care will be available for the patients suffering from IPF in this part of the world.

Structural and Electrical Integrity of Transesophageal Echocardiography Probes: Importance and Key Concepts.

The clinical utility of transesophageal echocardiography (TEE) is well-established for patients undergoing cardiac surgery. With the increase in percutaneous structural heart disease procedures that rely on TEE for procedural guidance, the use of TEE probes is expanding. Although there are well-established protocols for routine cleaning and decontaminating TEE probes between patient use, there is a lack of awareness and misconceptions about maintaining TEE probes' structural and electrical integrity. The electrical leakage test (ELT) is routinely performed between patient use. From a patient safety standpoint, the ELT is necessary to ensure the longevity of this expensive equipment and prevent disruptions to the workflow in a busy department caused by TEE probes being decommissioned due to probe damage. This technical communication aims to highlight the importance of maintaining TEE probes' structural and electrical integrity. The article also highlights and discusses probe handling techniques between patient use, emphasizing the ELT to ensure patient safety and compliance with national and international standards.

Effect of Ultraviolet-A and Riboflavin treatment on the architecture of the center and periphery of normal rat cornea: 7 days post treatment.

Corneal collagen cross-linking (CXL) is a treatment that is widely applied to halt the progression of ectatic diseases such as keratoconus by creating biomechanical strength in the cornea. Most of the studies assessed the effect of the CXL on the cornea without any differentiation of its effect between periphery and the center of the untreated control cornea especially after the 7 days of CXL application. We investigate the ultrastructural changes in the architecture of the center and periphery of rat corneas, 7 days after standard CXL application. Five Wistar rats (10 corneas) were used in the present study. The left eye corneas (5 mm area) were de-epithelialized and irradiated with standard CXL application using riboflavin and Ultraviolet-A (UVA) (3 mW/cm2 for 30 min). The right eye corneas were used as a control. The sclera-cornea button was removed and processed for electron microscopy. Digital images were captured with a bottom mounted Quemesa camera and analyzed using the iTEM software. The ultrastructure of epithelium, hemi-desmosomes, Bowman's layer and stroma were organized in both untreated control and CXL rat cornea in both untreated control and CXL rat cornea. Within the same CXL cornea, both the collagen fibril (CF) diameter and interfibrillar spacing at the center were significantly smaller compared to the peripheral diameter and spacing of the cornea. When comparing the untreated control and CXL cornea, the central interfibrillar spacing of the CXL cornea was significantly smaller than the central spacing the untreated control cornea. In the CXL cornea the peripheral spacing was significantly higher compared to the peripheral interfibrillar spacing of the untreated control cornea. Within the CXL cornea, the proteoglycans (PGs) area and density of the periphery was significantly higher compared to the area and density of the center of the cornea. It suggests that CXL was more effective at the periphery of the cornea. This could be due to the higher amount of leucine rich PG lumican and higher diffusion of oxygen and riboflavin at the periphery cornea.

Synthesis and Characterization of Functionalized Nanosilica for Zinc Ion Mitigation; Experimental and Computational Investigations.

Zinc is an essential trace metal and its concentration above 4ppm reduces the aesthetic value of water. This study explores the possibility of using functionalized nanohybrids as Zn(II) ion scavengers from aqueous solution. Functionalized nanohybrids were synthesized by the attachment of thiosemicarbazide to silica. The material was characterized by TGA, SEM, FTIR, EDX, and BET analysis, which revealed ligand bonding to silica. The functionalized silica was employed as Zn(II) ion extractant in batch experiments and removed about 94.5% of the Zn(II) ions at pH 7, near zero point charge (6.5) in 30 min. Kinetics investigations revealed that zinc adsorption follows an intra particle diffusion mechanism and first-order kinetics (K = 0.1020 min-1). The data were fitted to Freundlich, Dubinin-Radushkevich, and Langmuir models and useful ion exchange parameters were determined. The impact of co-existing ions on Zn(II) ion sequestration was also studied and it was found that the adsorbent can be used for selective removal of zinc with various ions in the matrix. Quantum mechanical investigations revealed that the Zn(II) ion adsorption on ZnBS1 is more favorable, having higher binding energy (BE) (-178.1 kcal/mol) and ∆H (-169.8), and making tridentate complex with the N and S sites of the chelating ligand. The negative ∆G and BE values suggest highly spontaneous Zn(II) adsorption on the modified silica even at low temperatures.

Efficient detection of nitric oxide a biomarker associated with COVID19 via N, P co-doped C60 fullerene: a computational study.

CONTEXT: Coronavirus (COVID-19) is a novel respiratory viral infection, causing a relatively large number of deaths especially in people who underly lung diseases such as chronic obstructive pulmonary and asthma, and humans are still suffering from the limited testing capacity. In this article, a solution is proposed for the detection of COVID-19 viral infections through the analysis of exhaled breath gasses, i.e., nitric oxide, a prominent biomarker released by respiratory epithelial, as a non-invasive and time-saving approach. Here, we designed a novel and low-cost N and P co-doped C60 fullerene-based breathalyzer for the detection of NO gas exhaled from the respiratory epithelial cells. This breathalyzer shows a quick response to the detection of NO gas by directly converting NO to NO2 without passing any energy barrier (0 kcal/mol activation energy). The recovery time of breathalyzer is very short (0.98 × 103 s), whereas it is highly selective for NO sensing in the mixture of CO2 and H2O gasses. The study provides an idea for the synthesis of low-cost (compared to previously reported Au atom decorated nanostructure and metal-based breathalyzer), efficient, and highly selective N and P co-doped C60 fullerene-based breathalyzer for COVID-19 detection. METHODS: The geometries of N and P-doped systems and gas molecules are simulated using spin-polarized density functional theory calculations.

Systematic surface bowing in 2D III-nitride monolayers.

In this article we report novel composite materials of bucky ball (C60 fullerene) and III-nitrides (BN, AlN, GaN, InN). The experimental feasibility of the novel composite materials is confirmed through negative binding energies and molecular dynamics simulations performed at 500 K. The structural properties of the novel composites are explored through density functional theory. An unusual phenomenon of surface bowing is observed in the 2D structure of the III-nitride monolayers due to the C60 sticking. This surface bowing systematically increases as one proceeds from BN → AlN → GaN → InN. The electron density difference and Hirshfeld charge density analysis show smaller charge transfer during the complexation, which is probably due to weak van der Waal's forces. The presence of van der Waal's forces is also confirmed by the Atom in Molecule analysis, Reduced Density Gradient Technique and Non-covalent Interaction analysis. This work provides a foundation for further theoretical and experimental studies of the novel phenomenon of systematic bowing in the 2D structure of III-nitride monolayers.

Synthesis of hydrazone-based polyhydroquinoline derivatives - antibacterial activities, α-glucosidase inhibitory capability, and DFT study.

In recent years, polyhydroquinolines have gained much attention due to their widespread applications in medicine, agriculture, industry, etc. Here, we synthesized a series of novel hydrazone-based polyhydroquinoline derivatives via multi-step reactions. These molecules were characterized by modern spectroscopic techniques (1H-NMR, 13C NMR, and LC-HRMS) and their antibacterial and in vitro α-glucosidase inhibitory activities were assessed. Compound 8 was found to be the most active inhibitor against Listeria monocytogenes NCTC 5348, Bacillus subtilis IM 622, Brevibacillus brevis, and Bacillus subtilis ATCC 6337 with a zone of inhibition of 15.3 ± 0.01, 13.2 ± 0.2, 13.1 ± 0.1, and 12.6 ± 0.3 mm, respectively. Likewise, compound 8 also exhibited the most potent inhibitory potential for α-glucosidase (IC50 = 5.31 ± 0.25 µM) in vitro, followed by compounds 10 (IC50 = 6.70 ± 0.38 µM), and 12 (IC50 = 6.51 ± 0.37 µM). Furthermore, molecular docking and DFT analysis of these compounds showed good agreement with experimental work and the nonlinear optical properties calculated here indicate that these compounds are good candidates for nonlinear optics.

Analysis of Readmissions Due to VTE-Using Hospital Data to Improve VTE Prophylaxis Compliance: A Quality Improvement Project.

Venous thromboembolism (VTE) is a preventable cause of mortality and morbidity. We performed a retrospective analysis of patient records to identify those readmitted with a diagnosis of VTE within 6 months of the primary admission. The records were evaluated to see whether thromboprophylaxis had been provided to patients at high risk for VTE. A total of 360 hospital encounters between August 1, 2018, and August 31, 2019, with VTE, 57 (16%) encounters were readmissions with a primary diagnosis of deep vein thrombosis within 180 days of their primary stay. A high proportion (44%) of these readmissions were within the first 30 days. 3% (n = 9) of patients developed pulmonary embolism; 35 (61%) did not receive thromboprophylaxis on their primary stay. Thromboprophylaxis is often not utilized appropriately in healthcare settings. Our study showed substantial incidence of hospital readmissions due to VTE which is consistent with prior studies conducted globally. A more stringent adherence to the protocol along with risk stratification may lower rates of VTE admission and reduce associated morbidity and mortality.

Efficient Detection of Nerve Agents through Carbon Nitride Quantum Dots: A DFT Approach.

V-series nerve agents are very lethal to health and cause the inactivation of acetylcholinesterase which leads to neuromuscular paralysis and, finally, death. Therefore, rapid detection and elimination of V-series nerve agents are very important. Herein, we have carried out a theoretical investigation of carbon nitride quantum dots (C2N) as an electrochemical sensor for the detection of V-series nerve agents, including VX, VS, VE, VG, and VM. Adsorption of V-series nerve agents on C2N quantum dots is explored at M05-2X/6-31++G(d,p) level of theory. The level of theory chosen is quite adequate in systems describing non-bonding interactions. The adsorption behavior of nerve agents is characterized by interaction energy, non-covalent interaction (NCI), Bader's quantum theory of atoms in molecules (QTAIM), frontier molecular orbital (FMO), electron density difference (EDD), and charge transfer analysis. The computed adsorption energies of the studied complexes are in the range of -12.93 to -17.81 kcal/mol, which indicates the nerve agents are physiosorbed onto C2N surface through non-covalent interactions. The non-covalent interactions between V-series and C2N are confirmed through NCI and QTAIM analysis. EDD analysis is carried out to understand electron density shifting, which is further validated by natural bond orbital (NBO) analysis. FMO analysis is used to estimate the changes in energy gap of C2N on complexation through HOMO-LUMO energies. These findings suggest that C2N surface is highly selective toward VX, and it might be a promising candidate for the detection of V-series nerve agents.

Implementation evaluation of a medical student-led intervention to enhance students' engagement with research: Findings and lessons learned.

INTRODUCTION: Medical colleges globally have student organizations that serve to enable students' involvement in research. However, details of their approach and activities are seldom published to serve as learning for student organizations in other settings. The Student Research Forum (SRF), a student organization based at a private medical school in Pakistan aims to facilitate students in acquiring research skills. Following the observation of a downward trajectory of student initiative and interest, SRF leadership restructured the organization and improve its impact. This study describes the development and implementation evaluation of the interventions. METHODOLOGY: The operational framework was revised using the Theory of Change by the core group. Major interventions included enhanced social media and outreach coordination, research workshops, journal clubs, and mentorship to increase research output, mentorship opportunities, and knowledge of medical research; ultimately improving quality in research. The outcomes generated over the course of the study's duration from July 2019 to September 2021 were analyzed using the process metrics of reach, adoption, and efficacy. RESULTS: As a result of the interventions, SRF expanded its reach by conducting a total of 41 events during the duration of the study, facilitated by social media growth on each of SRF's online platforms, with a 300% increase in followers on Facebook, and a nationwide network of 91 student ambassadors. An annual workshop series taught research skills to more than 3800 participants. Students leading their own events, SRF featuring international speakers, and the abstracts submitted to SRF's annual conference, along with the conference's reach of 10,000 students, are seen as improvements in the ToC-informed interventions' adoption. The efficacy of the interventions manifested as the REACH program allocated 56 research projects to vetted applicants. CONCLUSION: The applied interventions have accelerated SRF's progress towards achieving its long-term outcome of increased quality in research as translated by increased research output quantity, mentorship, and knowledge of medical research. Further evaluation is required to assess the success of the ToC. As SRF continues to grow, a continued analysis of the implementation outcomes is imperative to gauge its effectiveness.

Disparities in patient-resident physician communication and counseling: A multi-perspective exploratory qualitative study.

Effective communication between physicians and patients plays an integral role in clinical care. Gaps in a physician's ability to ensure effective communication, especially with patients from diverse backgrounds, are known causes of medical errors. This study explores the potential biases and disparities in patient-resident communication, which may influence a patient's quality of care. This exploratory qualitative study was conducted at the largest academic medical center in Pakistan. Purposive sampling was used to approach participants from surgery, medicine, obstetrics and gynecology, pediatrics and family medicine. Faculty, fellows and residents working in these departments and medical students in their fourth and fifth years of undergraduate education with prior experience of at least one month in these specialties during their clinical rotations were included. Focus group discussions (FGDs) lasting 45-60 minutes were conducted with each cohort of healthcare professionals separately, using a semi-structured interview guide. Sixty participants (19 males and 41 females, mean age: 32.9, SD: 10.9) took part in the study. Thematic analysis revealed five major themes. Four themes focused on residents' biases and patient disparities hindering patient-resident communication: (1) patient-resident gender discordance (2) ethnicity and language barriers, (3) differing social class of the patient, and (4) challenging patient-resident interactions (patients resistant to treatment, exceedingly inquisitive and those with multiple attendants, etc.). The fifth theme identified the need for a communication skills curriculum in postgraduate medical education. Opposite gender and discordant socioeconomic/cultural backgrounds of patients pose a challenge to effective patient-physician communication. Self-identification and awareness of residents' biases when interacting with patients can ensure their active elimination and improve their communication skills. Integrating these components in a standardized curriculum within postgraduate programs can enable resident-physicians to provide the same level of care and communicate more efficiently with patients of all backgrounds.

Alkali metal decorated C60 fullerenes as promising materials for delivery of the 5-fluorouracil anticancer drug: a DFT approach.

The development of effective drug delivery vehicles is essential for the targeted administration and/or controlled release of drugs. Using first-principles calculations, the potential of alkali metal (AM = Li, Na, and K) decorated C60 fullerenes for delivery of 5-fluorouracil (5FU) is explored. The adsorption energies of the 5FU on a single AM atom decorated C60 are -19.33, -16.58, and -14.07 kcal mol-1 for AM = Li, Na, and K, respectively. The results, on the other hand, show that up to 12 Li and 6 Na or K atoms can be anchored on the exterior surface of the C60 fullerene simultaneously, each of which can interact with a 5FU molecule. Because of the moderate adsorption energies and charge-transfer values, the 5FU can be simply separated from the fullerene at ambient temperature. Furthermore, the results show that the 5FU may be easily protonated in the target cancerous tissues, which facilitates the release of the drug from the fullerene. The inclusion of solvent effects tends to decrease the 5FU adsorption energies in all 5FU-fullerene complexes. This is the first report on the high capability of AM decorated fullerenes for delivery of multiple 5FU molecules utilizing a C60 host molecule.

Nano-porous C4N as a toxic pesticide's scavenger: A quantum chemical approach.

The sensing affinity of C4N is the most fascinating topic of research due to its excellent chemical and electronic properties. Moreover, owing to the highly active porous cavity, C4N can easily accommodate foreign molecules. Herein, we studied the adsorption properties of carbamate insecticides (CMs) namely, Dimetalin (DMT), Carbanolate (CBT), Isolan (ISO) and Propoxur (PRO) using density functional theory calculations. All the results are calculated at widely accepted ωB97XD functional along with 6-31G(d, p) basis set. The calculated counterpoise corrected interaction energy of the reported complexes ranges between -20.05 and -27.04 kcal/mol, however, the interaction distances are found to be higher than 2.00 Å. The values of interacting parameters depict that the carbamate molecules are physisorbed via noncovalent interactions that can easily be reversible. Moreover, the binding of selected insecticides notably changes the electronic structure of C4N. The electronic changes are characterized by the energies of HOMO & LUMO, their energy gaps and CHELPG charge transfer. The charge density difference between C4N surface and carbamate pesticides are characterized by EDD and CDA analysis. Moreover, the ab initio molecular dynamic study reveals that the complexes are stable even at 500 K. The photochemical sensing properties of C4N are estimated by time dependent UV-Vis calculations. The high sensitivity of C4N towards considered analytes enable it to act as a promising sensor for toxic pesticides.

A unique pre-endothelial layer at the posterior peripheral cornea: ultrastructural study.

This study was conducted to investigate the ultrastructure of a unique structures at the anterior side of the endothelium of the posterior peripheral cornea and compare their inner fibers to those of the limbus and sclera. The unique structures at the anterior side of endothelium was referred as a pre-endothelial (PENL) structures in the present manuscript. Ten anonymous-donor human corneoscleral rims (leftover after corneal transplants) were processed for electron microscopy. Semi-thin sections were examined using an Olympus BX53 microscope, and ultrathin sections were studied using a JOEL 1400 transmission electron microscope. A unique PENL structures was identified at the posterior peripheral cornea at a radial distance of approximately 70-638 µm, from the endpoint of Descemet's membrane. The PENL thinned out gradually and disappeared in the center. The contained an electron-dense sheath with periodic structures (narrow-spacing fibers), wide-spacing fibers, and numerous microfibrils. Typical elastic fibers were present in the sclera and limbus but were not observed in the PENL. This study revealed the existence of a new acellular PENL, containing unique fibrillar structures that were unseen in the corneal stroma. From the evidence describe in this paper we therefore suggest that PENL is a distinct morphological structure present at the corneal periphery.

Developing a communication-skills training curriculum for resident-physicians to enhance patient outcomes at an academic medical centre: an ongoing mixed-methods study protocol.

INTRODUCTION: Effective physician-patient communication is directly linked to enhanced patient safety, improved healthcare quality and health outcomes. Numerous studies have been done to implement and reinforce communication skills as core competencies to be acquired during residency training for providing culturally competent care. Pakistan has an ethnically diverse culture with people from varying diasporas. Hence there is a need to develop a curriculum that teaches cultural competency to residents. Thus, the aim of this study is (1) the identification of existing problems of communication skills among residents across various specialties, and (2) to strategise a communication skills curriculum by organising a conference of experts based on the Delphi method/estimate-talk-estimate method. METHODS AND ANALYSIS: This study is divided into two phases. The first phase will employ a mixed-methods approach whereby the perceptions of attendings, residents, fellows, nurses, medical students and patients about resident-patient communication will be assessed via validated surveys, focused group discussions and in-depth interviews. Quantitative and qualitative data will be analysed using Stata and NVivo, respectively. The second phase is the development of a communication skills curriculum for residents based on results from phase one and a Delphi consensus involving medical education experts. Both phases will be conducted at a tertiary care hospital in Karachi, Pakistan. ETHICS AND DISSEMINATION: This study has received ethical approval from the Ethical Review Committee at the Aga Khan University (2021-6041-17126). All participants will be mandated to provide informed consent and their confidentiality will be maintained by using de-identifiers and limiting access of the data to the research team only. The findings from this study will be presented in the form of original research papers.

Anodic SnO2 Nanoporous Structure Decorated with Cu2O Nanoparticles for Sensitive Detection of Creatinine: Experimental and DFT Study.

Advanced anodic SnO2 nanoporous structures decorated with Cu2O nanoparticles (NPs) were employed for creatinine detection. Anodization of electropolished Sn sheets in 0.3 M aqueous oxalic acid electrolyte under continuous stirring produced complete open top, crack-free, and smooth SnO2 nanoporous structures. Structural analyses confirm the high purity of rutile SnO2 with successful functionalization of Cu2O NPs. Morphological studies revealed the formation of self-organized and highly-ordered SnO2 nanopores, homogeneously decorated with Cu2O NPs. The average diameter of nanopores is ∼35 nm, while the average Cu2O particle size is ∼23 nm. Density functional theory results showed that SnO2@Cu2O hybrid nanostructures are energetically favorable for creatinine detection. The hybrid nanostructure electrode exhibited an ultra-high sensitivity of around 24343 µA mM-1 cm-2 with an extremely lower detection limit of ∼0.0023 µM, a fast response time (less than 2 s), and wide linear detection ranges of 2.5-45 µM and 100 µM to 15 mM toward creatinine. This is ascribed to the creation of highly active surface sites as a result of Cu2O NP functionalization, SnO2 band gap diminution, and the formation of heterojunction and Cu(1)/Cu(ll)-creatinine complexes through secondary amines which occur in the creatinine structure. The real-time analysis of creatinine in blood serum by the fabricated electrode evinces the practicability and accuracy of the biosensor with reference to the commercially existing creatinine sensor. The proposed biosensor demonstrated excellent stability, reproducibility, and selectivity, which reflects that the SnO2@Cu2O nanostructure is a promising candidate for the non-enzymatic detection of creatinine.

Synergic effects between boron and nitrogen atoms in BN-codoped C59-n BN n fullerenes (n = 1-3) for metal-free reduction of greenhouse N2O gas.

The geometries, electronic structures, and catalytic properties of BN-codoped fullerenes C59-n BN n (n = 1-3) are studied using first-principles computations. The results showed that BN-codoping can significantly modify the properties of C60 fullerene by breaking local charge neutrality and creating active sites. The codoping of B and N enhances the formation energy of fullerenes, indicating that the synergistic effects of these atoms helps to stabilize the C59-n BN n structures. The stepwise addition of N atoms around the B atom improves catalytic activities of C59-n BN n in N2O reduction. The reduction of N2O over C58BN and C57BN2 begins with its chemisorption on the B-C bond of the fullerene, followed by the concerted interaction of CO with N2O and the release of N2. The resulting OCO intermediate is subsequently transformed into a CO2 molecule, which is weakly adsorbed on the B atom of the fullerene. On the contrary, nitrogen-rich C56BN3 fullerene is found to decompose N2O into N2 and O* species without the requirement for activation energy. The CO molecule then removes the O* species with a low activation barrier. The activation barrier of the N2O reduction on C56BN3 fullerene is just 0.28 eV, which is lower than that of noble metals.