A reliable chemiresistive sensor of nickel-doped tin oxide (Ni-SnO2) for sensing carbon dioxide gas and humidity

Herein, we report the chemiresistive gas and humidity sensing properties of pristine and nickel-doped tin oxide (Ni-SnO₂) gas sensors prepared by a microwave-assisted wet chemical method. The structural and optical properties are characterised using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, ultraviolet spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The structural elucidation and morphology analyses confirm a particle size of 32–46 nm, tetragonal rutile crystal structure and small cauliflower-type surface appearance. Nickel doping can tune the structure of NPs and morphology. The tested carbon dioxide gas and humidity sensing properties reveal a rapid sensing performance with high-to-moderate sensitivity. Also, the materials favour gas sensing because their sensitivity is enhanced with the increase in nickel concentration. The sensing results suggest that nickel is a vibrant metal additive to increase the gas sensitivity of the sensor. However, nickel doping decreases the electron density and increases the oxygen vacancies. Ultimately, the gas sensor produces highly rapid sensing with a response time of 4 s.

Herein, we report the chemiresistive gas and humidity sensing properties of pristine and nickel-doped tin oxide (Ni-SnO₂) gas sensors prepared by a microwave-assisted wet chemical method.

A comparison of oral midazolam and oral dexmedetomidine as premedication in pediatric anesthesia

CONTEXT

Oral premedication is widely used in pediatric anesthesia to provide preoperative anxiolysis and ensure smooth induction. Midazolam is currently the most commonly used premedicant, but newer drugs such as the α2-agonists have emerged as alternatives for premedication in children.

AIMS

The aim of this study was to compare clinical effects of oral midazolam and oral dexmedetomidine on preanesthetic sedation and postoperative recovery profile in children.

SETTINGS AND DESIGN

Randomized controlled trial.

MATERIALS AND METHODS

We performed a prospective, randomized, controlled study in 60 children, aged 1-7 years undergoing elective, minor, lower abdominal surgeries under general anesthesia. Patients were randomly assigned to receive either oral midazolam 0.75 mg/kg (Group M, n = 30) or oral dexmedetomidine 4 μg/kg (Group D, n = 30) 40 min prior to mask induction. Preoperative sedation and anxiolysis, the response at parental separation, quality of mask acceptance and recovery profile were compared for the two groups.

STATISTICAL ANALYSIS USED

Results were analyzed using unpaired Student's t-test and Chi-squared test. P < 0.05 was considered statistically significant.

RESULTS

There was no significant difference in the levels of preoperative sedation and anxiolysis between the two groups, but the onset of sedation was significantly faster with midazolam (18.90 ± 3.68 min) than with dexmedetomidine (30.50 ± 4.44 min). Response to parental separation and quality of mask acceptance was comparable between two groups (P > 0.05). The incidence of postoperative agitation was significantly less in the dexmedetomidine group (P < 0.05).

CONCLUSIONS

In this study, premedication with oral dexmedetomidine produced equally effective preoperative sedation and a better recovery from anesthesia in children in comparison to oral midazolam.

Outcome of Interlay Grafting in Type 1 Tympanoplasty for Large Central Perforation

A prospective, cohort, clinical study was conducted at Dr. D. Y. Patil Hospital, Kolhapur from August 2010 to August 2013. The aim was to evaluate the results of type 1 interlay tympanoplasty with respect to graft uptake, hearing improvement and complications. Total of 100 cases with a mucosal type of chronic suppurative otitis media and a large central perforation (involving more than 50 % of tympanic membrane) were operated for type 1 tympanoplasty where the graft was placed by interlay method (below the fibro-squamous layer and above the mucosal or endothelial layer). Patients were followed up with ear microscopy at each follow up visit and an audiometry at the end of 3rd month. Statistical analysis was done by statcal software using paired t test and two sample t test for proportion. 96 (96 %) cases had a successful graft uptake. The mean pre-operative air-bone gap was 36.42 ± 12.0 dB; whereas the mean post-operative air-bone gap was 9.7 ± 6.71 dB. Except for residual perforation in four patients and partial tympanomeatal flap necrosis in two patients no other complications were encountered. Thus, we conclude that, the interlay tympanoplasty is a safe and effective method of graft placement for large central perforation.

Ultra-sensitive polyaniline–iron oxide nanocomposite room temperature flexible ammonia sensor

We report for the first time a room temperature smart NH₃sensor based on PAni–Fe₂O₃nanocomposite loading on flexible PET substrate byin situchemical oxidative polymerization method.

Electrochemical supercapacitor development based on electrodeposited nickel oxide film

A nickel oxide (NiO) electrode has been synthesized electrochemically, which is envisaged for supercapacitor application.

Bio-green synthesis of Ni-doped tin oxide nanoparticles and its influence on gas sensing properties

Using a novel, cost-effective and environmentally friendly biosynthesis method, Ni-doped SnO₂ nanoparticles have been synthesized. Gas sensing results suggest that the Ni-dopant is a promising additive to fabricate low cost SnO₂ based sensors.

Studies on facile synthesis of polyaniline/cadmium sulfide composites and their morphology

A composite of polyaniline (PANI) and cadmium sulfide (CdS) has been prepared via chemical bath deposition with crystalline structures which is confirmed from the X-ray diffraction (XRD) studies. Scanning electron microscopic studies and XRD have shown that the morphology and crystallinity of the materials in the composite have apparently changed after the formation of composite. The transmission electron microscopic study has revealed that there is an increase in the crystallite size of CdS and its impregnation into the granular pillar-like structure of PANI. The absorption edge of the composite red shifted as compared to that of CdS and blue shifted with respect to that of PANI. Fourier transform infrared spectroscopic studies show a clear shifting of wave numbers indicating the interaction between CdS and PANI due to the strengthening of the C=C bond in PANI.

Systematic interconnected web-like architecture growth of sprayed TiO2 films

Systematic improvement in interconnected web-like architecture with thickness of TiO2 films synthesized by spray pyrolysis method is reported and characterized for the structural, optical, surface morphological, and wettability properties. Deposited TiO2 films were crystalline with [120] direction orientation, uniform and adherent to the glass substrate. Interestingly, with increase in film thickness, fuzzy and blurred web-like architecture becomes more clear and sharp with well-defined boundaries. The band gap energy was decreased with increase in film thickness. Change in surface architecture resulted into smaller surface wettability in thick film compared to thin one.

Rhinocerebral mucormycosis: A deadly disease on the rise

According to WHO, there will be epidemic of diabetes world over and India is going to be 'A diabetes capital of the world' by 2025. With the increasing incidence of diabetes, the associated complications are also bound to increase. Rhinocerebral mucormycosis is one of them.Rhinocerebral Mucormycosis is an opportunistic, fulminating fungal infection, caused by Rhizopus species of order of mucorales, frequently seen in diabetic and immunocompromised patients. Mucormycosis has a very high mortality rate.Early diagnosis and treatment with Amphotericin-B is the key to combat this disease successfully. We have seen 13 cases in last 3 years (2002-2005) in our area. This incidence is significant, as this type of cases were rarely seen before 2002, in this geographical area. We present an account of these cases; treatment strategies adopted, review of literature, and highlight 'the role of ENT surgeon in diagnosis and management of this dreadful disease'.