In situ generation of turbostratic nickel hydroxide as a nanozyme for salivary glucose sensor.

Among the 3d-transition metal hydroxide series, nickel hydroxide is a well-studied electroactive catalyst. In particular, nickel hydroxide and its composite materials are well-suited for non-enzymatic glucose sensing. The electrocatalytic efficiency of nickel hydroxide is attributed to the thickness or to be precise, the thinness of the electroactive layer. Herein, we have successfully prepared metallic nickel@nickel hydroxide nanosheets through a straightforward one-pot solvothermal method. We were able to electrochemically generate a highly sensitive α-Ni(OH)2 on the nanosheets. The dynamic generation and synergy between α- and ß-Ni(OH)2, imparts a glucose oxidase enzyme-like ability to the catalyst. Our proposed nickel nanozyme exhibits a good sensitivity of 683 µA mM-1 cm-2 for glucose. The sensor operates in the range of 0.001-3.1 mM, with a lower limit of detection (LOD) of 9.1 µM and exhibits a response time of ≈00.1 s. Nickel-nanozyme demonstrated better selectivity for glucose in the presence of interfering compounds. Notably, the sensor does not suffer from an interfering oxygen evolution reaction. This greatly improves sensitivity in glucose detection in lower concentrations making the sensor viable to measure salivary glucose levels. In this study, we demonstrate that our sensor can detect glucose in human saliva. The real sample analysis was carried out with saliva samples from three healthy human volunteers and one prediabetic volunteer. Our proposed sensor measurements show excellent agreement with calculated salivary glucose levels with 98% accuracy in sensing glucose in real saliva samples.

MnCo2O4 Spinel Nanorods for Highly Sensitive Electrochemical Detection of Nitrite.

The rational design of nitrite sensors has attracted significant research interest due to their widespread use and the associated risks of methemoglobinemia and carcinogenicity. The undisclosed nitrite-sensing performance of the spinel cobaltite MnCo2O4 (MCO) prepared by an oxalate-assisted coprecipitation method is reported in this study. Spectroscopy and microscopy investigations revealed the formation of uniform MCO nanorods with a high aspect ratio. The electrocatalytic nitrite oxidation at the MCO-coated glassy carbon electrode (MCO/GCE) indicated the promising performance of the synthesized material for nitrite sensing. MCO/GCE detects nitrite in a concentration range of 5 µM to 3 mM and has a limit of detection of 0.95 µM with a higher sensitivity of 857 µA mM-1 cm-2 in a response time of 4 s. In MCO, the mixed-valence states of Co2+/Co3+ confer a high electrical conductivity, and higher valent redox couples of Mn and Co impart remarkable electrocatalytic activity toward nitrite oxidation. MCO spinel undergoes facile and ultrafast faradaic reactions to mediate nitrite oxidation. Additionally, the mesopores of MCO nanorods facilitate the rapid diffusion of electrolyte and nitrite ions. Employing the electrode in sensing nitrite in milk, lake, and tap water samples further validates its potential application in real-life testing. MCO spinel nanorods showcase promising scope for utilization in the electrochemical sensing of nitrite and inspire further exploration of transition-metal oxide-based mixed-spinel materials.

Green-Synthesized Amino Carbons for Impedimetric Biosensing of E. coli O157:H7.

This study describes the synthesis of amino-functionalized carbon nanoparticles derived from biopolymer chitosan using green synthesis and its application toward ultrasensitive electrochemical immunosensor of highly virulent Escherichia coli O157:H7 (E. coli O157:H7). The inherent advantage of high surface-to-volume ratio and enhanced rate transfer kinetics of nanoparticles is leveraged to push the limit of detection (LOD), without compromising on the selectivity. The prepared carbon nanoparticles were systematically characterized by employing CO2-thermal programmed desorption (CO2-TPD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-visible), and transmission electron microscopy (TEM). The estimated limit of detection of 0.74 CFU/mL and a sensitivity of 5.7 ((ΔRct/Rct)/(CFU/mL))/cm2 in the electrochemical impedance spectroscopy (EIS) affirm the utility of the sensor. The proposed biosensor displayed remarkable selectivity against interfering species, making it well suited for real-time applications. Moreover, the chitosan-derived semiconducting amino-functionalized carbon shows excellent sensitivity in a comparative analysis compared to highly conducting amine-functionalized carbon synthesized via chemical modification, demonstrating its vast potential as an E. coli sensor.

Rod-Shaped Spinel Co3O4 and Carbon Nitride Heterostructure-Modified Fluorine-Doped Tin Oxide Electrode as an Electrochemical Transducer for Efficient Sensing of Hydrazine.

Engineering low-cost and efficient materials for sensing hydrazine (HA) is critical given the adverse effects of high concentrations on humans. We report an efficient electrode made up of rod-shaped Co3O4/g-C3N4 (Co3O4/graphitic carbon nitride (GCN))-coated fluorine-doped tin oxide as a desirable electrode for the detection of HA. GCN is synthesized by the thermal decomposition of melamine, Co3O4, and the heterostructure is grown by a hydrothermal process. The as-prepared materials were characterized by using spectroscopic and microscopic techniques. The voltammetric studies showed that HA can be oxidized at a lower onset potential of 0.24 V vs reference Ag/AgCl, and the composite yielded a significantly enhanced oxidation peak current than the pure components because of the high electrocatalytic activity and the synergy between Co3O4 and GCN. By employing chronoamperometry, the proposed sensor can detect HA in a wide range with a high sensitivity of 819.52 µA mM-1 cm-2 and a detection limit of 3.14 µM. The high conductivity of Co3O4, enhanced electroactive surface area, the rich redox couples of Co2+/Co3+, and the additional catalytic sites from GCN are responsible for the high performance of the heterostructure.

Hybridization of Co3S4 and Graphitic Carbon Nitride Nanosheets for High-performance Nonenzymatic Sensing of H2O2.

The development of efficient H2O2 sensors is crucial because of their multiple functions inside and outside the biological system and the adverse effects that a higher concentration can cause. This work reports a highly sensitive and selective non-enzymatic electrochemical H2O2 sensor achieved through the hybridization of Co3S4 and graphitic carbon nitride nanosheets (GCNNS). The Co3S4 is synthesized via a hydrothermal method, and the bulk g-C3N4 (b-GCN) is prepared by the thermal polycondensation of melamine. The as-prepared b-GCN is exfoliated into nanosheets using solvent exfoliation, and the composite with Co3S4 is formed during nanosheet formation. Compared to the performances of pure components, the hybrid structure demonstrates excellent electroreduction towards H2O2. We investigate the H2O2-sensing performance of the composite by cyclic voltammetry, differential pulse voltammetry, and amperometry. As an amperometric sensor, the Co3S4/GCNNS exhibits high sensitivity over a broad linear range from 10 nM to 1.5 mM H2O2 with a high detection limit of 70 nM and fast response of 3 s. The excellent electrocatalytic properties of the composite strengthen its potential application as a sensor to monitor H2O2 in real samples. The remarkable enhancement of the electrocatalytic activity of the composite for H2O2 reduction is attributed to the synergistic effect between Co3S4 and GCNNS.

Role of Virtual Reality in Pain Perception of Patients Following the Administration of Local Anesthesia.

BACKGROUND: Dental anxiety and anxiety-related avoidance of dental care creates significant problems for the patients and dental practitioners. Administration of local anesthesia is one of the procedures which results in increased anxiety level among patients. AIM: The aim of this study was to study the effectiveness of virtual reality (VR) as a distraction tool during the administration of local anesthesia in patients undergoing a dental procedure. MATERIALS AND METHODS: Fifty patients were randomized into two groups, namely, control group (n = 25) and study group (n = 25). Preoperative, intra-operative, and postoperative pulse rate and oxygen saturation were measured using pulse oximeter for all the patients. Local anesthesia was administered without the use of VR for the control group and with the VR for the study group. STATISTICAL ANALYSIS: The data were evaluated using the Statistical Package for the Social Sciences 20. Student's t-test was used to compare the variables. RESULTS: Statistically significant results were obtained for preoperative and postoperative oxygen saturation, intraoperative pulse rate, and postoperative visual analog scale pain scale. CONCLUSION: The findings of the current study indicate that immersive VR is an effective distraction tool to alleviate the anxiety of the patient.

Esthetic lip repositioning: A cosmetic approach for correction of gummy smile - A case series.

Gummy smile has been a prevalent esthetic disorder commonly affecting younger individuals due to various causes such as skeletal, dento-alveolar, or soft-tissue origin. It can be due to jaw deformities, altered passive eruption, or tooth malpositioning. Usually, the corrective measures incorporate orthognathic surgery and orthodontic treatment. Orthognathic surgery results in significant morbidity and hospitalization. Lip repositioning can be employed as an alternative cosmetic treatment modality for the correction of an excessive gingival display with minimal risk or side effects. Although there are many articles existing in the literature on this topic, a series of three cases is unique in demonstrating the esthetic smile enhancement in an orthodontic patient and also a combination of lip-repositioning technique and laser-assisted crown lengthening in vertical maxillary excess cases. This case series also showed the predictability of lip-repositioning technique with a follow-up of 2 years.

Blended Module-Based Teaching in Biostatistics and Research Methodology: A Retrospective Study with Postgraduate Dental Students.

Information technology has stimulated efforts to reform teaching methods in dental education. Most of these efforts involve a shift from conventional mode to the more technology-savvy and student-centered approach. The aim of this study was to compare postgraduate dental students' academic performance using two teaching methodologies (video-based learning and blended module-based learning) in a biostatistics and research methodology course in a master's program at a dental college in India. This retrospective study involved two groups of students enrolled in the master's program with different years of admission: Group I in 2013-14 (n=80) and Group II in 2015-16 (n=80). Group I students learned the subjects with video-based learning, whereas Group II students were taught using a blended module program using a small-group learning system called Process-Oriented Guided Inquiry Learning (POGIL). The students' final course evaluation (summative assessment) and formative assessment (during course assessments) were compared for the two groups. The students' final course evaluation was derived from an end-of-year written examination, whereas the formative assessment was recorded with written tests and projects during the course. In the results, the summative assessment did not show a significant difference between Group I (68.2±13.4) and Group II (66.4±11.9) (p=0.39). The formative assessment showed a significant difference (p<0.001) in favor of the Group II students. In this study, the blended module-based teaching produced similar scores on the final exam to the video-based lectures, but it produced significantly better results on the in-course assessments. The latter finding could be attributed to the incorporation of small-group learning and POGIL.

Comparative estimation of sulfiredoxin levels between chronic periodontitis and healthy patients - A case-control study.

BACKGROUND: Growing evidence suggests that oxidative stress forms a key component in the etiopathogenesis of periodontitis. Studies have shown potential antioxidants responsible for combating the pro-oxidants which stress the periodontium. But, peroxiredoxin-sulfiredoxin system is the least explored in periodontal disease. METHODS: A case-control study was conducted on 30 participants who fulfilled the inclusion criteria from the Department of Periodontics, Saveetha Dental College and Hospital, Chennai, India. The patients were divided into two groups: 1) Group A- healthy controls (n = 18), 2) Group B- patients with generalized chronic periodontitis (n = 17). Following clinical examination, gingival tissue samples were procured from both the groups and subjected to protein quantification by Lowry method. The samples with adequate protein concentration (n = 30) from the two groups were further analyzed by enzyme-linked immunosorbent assay for estimation of sulfiredoxin levels. RESULTS: Sulfiredoxin levels were significantly higher in the gingival tissues of chronic periodontitis patients (171.20 ± 16.97 ng/mL) than in healthy controls (131.20 ± 22.87) with P < 0.001. Also, the levels of sulfiredoxin in gingival tissue of periodontitis patients positively correlated with site-specific probing depth (r = 0.67; P = 0.007) and clinical attachment level (r = 0.55; P = 0.035). CONCLUSIONS: The present study was a novel attempt to estimate the levels of sulfiredoxin which was significantly elevated in the diseased sites of patients with chronic periodontitis. Future studies are required to probe the role of sulfiredoxin in the etiopathogenesis of periodontal disease.

Comprehensive rehabilitation using dental implants in generalized aggressive periodontitis.

Generalized aggressive periodontitis (GAP) is a debilitating form of the disease and it results in deteriorating effects on the esthetic and functional aspects of the oral cavity. This case report describes the comprehensive rehabilitation of GAP patient using dental implants. The treatment planning involved thorough scaling and root planning (SRP) with oral hygiene instructions. The patient was motivated to adhere to a strict oral hygiene regimen following which periodontal flap surgery employing guided tissue regeneration and bone grafts was performed. Bacterial culture for anaerobic microorganisms was done using a gas pack pre- and postperiodontal treatment to confirm the effectiveness of the periodontal treatment regimen and also to proceed with dental implant placement. The rigorous maintenance program ensured the stability of the periodontium following which immediate placement of dental implants in the maxillary and mandibular anterior region was done. The fixed metal-ceramic prosthesis was fabricated in a step-by-step process and the patient was recalled on a periodic basis over a 3-year follow-up duration. This case is a testimonial to the postperiodontal treatment long-term stability with excellent patient cooperation and strict maintenance protocol.

Herbs as an antioxidant arsenal for periodontal diseases.

Herbal medicines have long been used as a traditional mode of therapy for various ailments in India. They are being used increasingly as dietary supplements to ward off common diseases. Periodontal diseases are highly prevalent and can affect up to 90% of the world population. Gingivitis is the mild form whereas periodontitis results in an irreversible loss of supporting structures of the teeth. Even though periodontal pathogens form a crucial component in the etiopathogenesis of periodontitis, there is a growing body of evidence suggesting oxidative stress playing a pivotal role in the disease initiation and progression. Studies have shown a direct correlation between increased levels of biomarkers for tissue damage induced by reactive oxygen species (ROS) to the severity of periodontal disease. Thus, the focus of attention has revolved back to herbal medicines due to their wide spectrum of biological and medicinal activities, lower costs, and higher safety margin. Internet databases Pubmed and Google Scholar were searched, and the most relevant articles were considered for review. This review briefly describes the various herbs with antioxidant capacity and their potency in the treating periodontal disease.

Role of sulfiredoxin in systemic diseases influenced by oxidative stress.

Sulfiredoxin is a recently discovered member of the oxidoreductases family which plays a crucial role in thiol homoeostasis when under oxidative stress. A myriad of systemic disorders have oxidative stress and reactive oxygen species as the key components in their etiopathogenesis. Recent studies have evaluated the role of this enzyme in oxidative stress mediated diseases such as atherosclerosis, chronic obstructive pulmonary disease and a wide array of carcinomas. Its action is responsible for the normal functioning of cells under oxidative stress and the promotion of cell survival in cancerous cells. This review will highlight the cumulative effects of sulfiredoxin in various systemic disorders with a strong emphasis on its target activity and the factors influencing its expression in such conditions.