Clinical study of tongue pain: Serum zinc,vitamin B12, folic acid,and copper concentrations,and systemic disease

The aim of this retrospective study of patients with tongue pain who showed no improvement after initial treatment and examination was to find out if their lack of response correlated with serum concentrations of zinc, vitamin B12, folic acid, and copper, and if it was associated with coexisting systemic diseases. We studied 311 patients for whom we had data about serum concentrations of these elements, and recorded whether they had any systemic diseases and were taking medicines regularly. One patient (0.3%) had a copper concentration outside the reference range; 2 patients (0.6%) had folic acid concentrations outside the reference range. The corresponding number for vitamin B12 was 5 (2%), and for zinc 30 (10%). The systemic diseases with the highest rates were: hyperlipidaemia (n = 53, 17%), gastritis or gastric ulcer (n = 51, 16%), angina pectoris (n = 39, 13%), diabetes mellitus (n = 31, 10%), thyroid disease (n = 31, 10%), mild mental disorder (n = 27, 9%), hypertension (n = 18, 6%), cerebral infarction (n = 17, 6%), leiomyoma (n = 15, 5%) and anaemia (n = 15, 5%).     

Degree of conversion and monomer elution of CQ/amine and TPO adhesives

Objective

To evaluate the effect of photo-initiator on the degree of conversion (DC) and elution of Bis-GMA and HEMA for 8 one-step adhesive formulations.

Methods

We used Scotchbond Universal (‘SBU-CQ/amine_4.0’, 3M ESPE), containing about 2 wt% camphorquinone (CQ) and 2 wt% ethyl-4-dimethylamino benzoate (EDMAB), an experimental ‘SBU-TPO_2.1’ version, containing 2.1 wt% diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and 6 experimental LUB adhesives (Kuraray Noritake), namely ‘LUB-CQ/amine_0.7’, ‘LUB-CQ/amine_1.4’, ‘LUB-CQ/amine_4.0’, ‘LUB-TPO_0.35’, ‘LUB-TPO_0.7’ and ‘LUB-TPO_2.0’, respectively containing 0.35 wt% CQ and 0.35 wt% EDMAB, 0.7 wt% CQ and 0.7 wt% EDMAB, 2.0 wt% CQ and 2.0 wt% EDMAB, 0.35 wt% TPO, 0.7 wt% TPO, and 2.0 wt% TPO. DC was measured using micro-Raman spectroscopy. Additional specimens were immersed in ethanol for 24 h to determine the elution of Bis-GMA and HEMA using HPLC.

Results

DC of the respective SBU and LUB adhesives was alike at high photo-initiator concentration. At low concentration, TPO was significantly more efficient than CQ/amine (LUB adhesives only). A statistically significant positive photo-initiator concentration effect on DC was noted for both CQ/amine and TPO (LUB adhesives only). A statistically significant inverse photo-initiator concentration effect on HEMA elution was noted for both the CQ/amine- and TPO-containing LUB adhesives. A significantly strong correlation was found between DC and Bis-GMA elution (R² = 0.744, p = 0.026), and between DC and HEMA elution (R² = 0.913, p = 0.002) for the LUB adhesives.

Significance

The photo-initiator kind and concentration affect DC and the Bis-GMA/HEMA elution. TPO can be used as an alternative photo-initiator for CQ/amine.     

Poly(N-methylaniline)/nickel modified carbon paste electrode as an efficient and cheep electrode for electrocatalytic oxidation of formaldehyde in alkaline medium

This research in finding a cheap and efficient catalyst for electrooxidation of formaldehyde give us an attempt to make and examine the behavior of poly(N-methylaniline)/nickel modified carbon paste electrode (Ni/P(NMA)/MCPE) in absence and presence of formaldehyde. This involves in situ electropolymerization of N-methylaniline at carbon paste electrode, which is following to the incorporation of Ni(II) to polymeric layer by immersion of modified electrode in 1.0 M nickel sulphate solution. The electrocatalytic oxidation of formaldehyde was studied by cyclic voltammetry and chronoamperometry methods. The effects of scan rate and formaldehyde concentration on the electrocatalytic oxidation of formaldehyde were also investigated at the surface of Ni/P(NMA)/MCPE. The diffusion coefficient (D = 14.1 × 10⁻⁵ cm² s⁻¹), and some kinetic parameters such as the transfer coefficient (α = 0.45) and also second-order rate constant (k = 8.96 × 10⁻⁴ cm³ mol⁻¹ s⁻¹) of formaldehyde were calculated.     

A tentative model for d-glucose turnover in human saliva

Objective

The aim of the present study is to propose a tentative model for d-glucose turnover in human saliva. The whole saliva and the saliva from parotid and submandibular/sublingual glands were collected by use of the Salivette™.

Results

The saliva glucose concentration was measured by the hexokinase method, saliva bacteria glycolysis by use of d-[5-³H] glucose, and the saliva ATP content by the luciferase method. The concentration of glucose amounted to 43.9 ± 6.3 (n = 29), 197.5 ± 17.3 (n = 29), 104.0 ± 12.4 (n = 27) μM in whole saliva, parotid saliva and submandibular/sublingual saliva, respectively. The rate of d-glucose utilization by oral bacteria at a physiological concentration of d-glucose in saliva (50 μM) was estimated at 0.047 ± 0.003 (n = 11) nmol/min per 10⁶ bacteria. Unstimulated salivary d-glucose turnover rate, as calculated from the amount of glucose secreted in saliva which comes from parotid and submandibular and sublingual glands represented 214.6 ± 19.1%/min. In order for salivary d-glucose production to match bacterial utilization of the hexose, the total number of oral bacteria was estimated at about 2.0 × 10⁹ bacteria, in fair agreement with previously published data.

Conclusion

This study thus provides support for a tentative model for d-glucose turnover in human saliva.     

Concentration and fate of histatins and acidic proline-rich proteins in the oral environment

Saliva plays a critical role in the protection of oral hard and soft tissues and contains a multitude of constituents with well-characterized biological activities in vitro. Among these are histatins and acidic proline-rich proteins (PRPs). Nevertheless, few functional studies have recognized the structural instability of these proteins in the proteolytic environment of whole saliva. The aim of this investigation was to determine histatin and acidic PRP levels in parotid secretion (PS) and in whole saliva (WS) as well as to establish their susceptibility to proteolysis in these salivary fluids. Using cationic polyacrylamide gel electrophoresis and densitometric analysis the average total histatin concentration (histatin 1 + 3 + 5) in WS was determined to be 33.3 ± 16.7 μg/ml (n = 22) and the average total acidic PRP concentration (PRP1/PIF-s + PRP3/PIF-f) was 427.9 ± 123.3 μg/ml (n = 22). Histatin and acidic PRP concentrations in PS were 6 and 1.5 times higher than in WS (n = 7), respectively. WS histatin and acidic PRP levels each correlated significantly with WS total protein concentrations (P < 0.01 and P < 0.05, respectively), as well as with each other (P < 0.01). Stability studies of histatin 3 and PRP1/Pif-s in PS revealed t^1/2 times of 7.2 ± 5.5 and 50.3 ± 24.8 h, respectively (n = 7). Histatin 3 (40 μg/ml) and PRP1 (400 μg/ml), added to WS in concentrations equivalent to their concentrations in PS, disappeared at a much faster rate, with t^1/2 values of 1.7 ± 1.6 min and 29.3 ± 15.3 min, respectively (n = 7). The data indicate that proteolysis in WS is an important factor in explaining the substantially lower concentrations of histatins and acidic PRPs in WS as compared to in glandular secretions.     

Preparation of poly N,N-dimethylaniline/ferrocyanide film modified carbon paste electrode: Application to electrocatalytic oxidation of l-cysteine

Functionalized poly N,N-dimethylaniline film was prepared by adsorption of ferrocyanide onto the polymer forming at the surface of carbon paste electrode (CPE) in aqueous solution. The electrocatalytic ability of poly N,N-dimethylaniline/ferrocyanide film modified carbon paste electrode (PDMA/FMCPE) was demonstrated by oxidation of l-cysteine. Cyclic voltammetry and chronoamperometry techniques were used to investigate this ability. In the optimum pH (6.00), the electrocatalytic ability about 480 mV and the catalytic reaction rate constant, (k_h), can be seen 3.08 × 10³ M⁻¹ s⁻¹. The catalytic oxidation peak current determined by cyclic voltammetry method was linearly dependent on the l-cysteine concentration and the linearity range obtained was 8.00 × 10⁻⁵ –2.25 × 10⁻³ M. Detection limit of this method was determined as 6.17 × 10⁻⁵ M (2σ). At a fixed potential under hydrodynamic conditions (stirred solution), the calibration plot was linear over the l-cysteine concentration range 7.40 × 10⁻⁶ M–1.38 × 10⁻⁴ M. The detection limit of the method was 6.38 × 10⁻⁶ M (2σ).     

Development of amperometric arsine gas sensor using gold-modified diamond electrodes

Amperometric gas sensor of arsine was developed using gold-modified diamond electrodes as the working electrodes. The detection method was conducted in high concentration of H₂SO₄. The reaction was declared based on two oxidation steps, involving oxidation of As³⁻ to As⁰ at mild potential in strong acid, followed by electrochemical oxidation of As⁰ to As³⁺ at gold-based electrodes. Linear calibration curve was observed in the concentration range of 5–50 ppb (r² = 0.985) with detection limit of ∼4.43 ppb (S/N = 3). Current decreasing of measurement was found ∼5.5% for 5 measurements. However, better stability was observed after the 5th measurement, indicated that the sensor could be applied for long time measurement. Investigation to several possible interference gasses, i.e. SO₂, H₂S, NO, NO₂, CO, O₃ and H₂ indicated no significant interference of the gas to arsine measurements.     

Electrochemistry of magnolol and interaction with DNA

The electrochemical behaviors of magnolol have been studied at glassy carbon electrode using cyclic voltammetry, linear sweep voltammetry and chronocoulometry. Moreover, its interaction with DNA was investigated in solution by electrochemical methods and ultraviolet–visible spectroscopy. The experiment results indicated that the electrochemical oxidation of magnolol was an irreversible process with one proton and one electron transfer. The electron transfer coefficient (α) was calculated to be 0.441 ± 0.001. At the scan rate from 100 mV/s to 450 mV/s, the electrode process was controlled by the adsorption step and at the range of 600–950 mV/s the electrochemical oxidation was diffusion controlled process. The corresponding electrochemical rate constant (k_s) was 0.0760 ± 0.0001 s⁻¹. Through chronocoulometry experiment, the diffusion coefficient (D) and the surface concentration (Γ) were obtained as (3.76 ± 0.01) × 10⁻⁷ cm²/s and (2.98 ± 0.01) × 10⁻¹⁰ mol/cm². In addition, the interaction of magnolol and DNA was ascribed to be electrostatic interaction and the calculated association constant (β) and Hill coefficient (m) were 1.14 × 10⁵ M⁻¹ and 0.973. At last a sensitive and convenient electrochemical method was proposed for the determination of magnolol.     

Subcritical crack growth behavior and life data analysis of two types of dental Y-TZP ceramics

Objectives

The aim of this study was to evaluate the mechanical properties and the subcritical crack growth behavior of a presintered dental Y-TZP (Kavo Everest ZS) and a hot isostatic pressed Y-TZP (Kavo Everest ZH) and to perform life data analysis.

Methods

For each material 150 bending bars were produced. The initial fracture strength was determined in a four-point bending test. The subcritical crack growth parameters n and A were determined in a dynamic fatigue method at four decreasing loading rates from 110 MPa/s to 0.11 MPa/s in distilled water at 38 °C. For each loading rate Weibull statistics were performed and the Weibull moduli m and characteristic strengths σ₀ were calculated. Using these data, strength-fracture probability-life time (SPT) predictions were derived for 1 day, 1 year, 5 years and 10 years, based on a static crack growth mechanism.

Results

The “hipped” Y-TZP ceramic exhibited a higher initial strength (σ_c = 1618.18), characteristic strength (σ₀ = 837.15) and fracture toughness (K_IC = 4.52 MPa/m^1/2) than the pre-sintered ceramic (σ_c = 1431, σ₀ = 745.46 and K_IC = 3.17 MPa/m^1/2, respectively). Fatigue parameters, n and A, were 28.5 and 7.97 × 10⁻²⁴ for Everest ZH and 30.15 and 5.47 × 10⁻²⁰ for Everest ZS. The predicted fracture stress at 5% failure probability for a lifetime of 10 years was 259.34 MPa for Everest ZH and 263.2 MPa for Everest ZS.

Conclusions

Although the “hipped” Y-TZP showed favorable initial mechanical properties, no significant difference could be found in the susceptibility of both ceramics to subcritical crack growth and their long-term strength.     

Precise coulometric determination of redox inert anions based on electrolysis at the aqueous|organic solution interface

The flow cell proposed previously for the rapid and coulometric determination of cations based on the electrochemical ion transfer at the aqueous|organic solution interface was improved to be applicable to the determination of anions. The developed cell was composed of a porous poly(tetrafluoroethylene) tube (1.0 mm in inner diameter), a copper wire (0.8 mm in diameter) inserted into the tube, a platinum wire placed outside the tube, an organic solution into which the tube was immersed and a reference electrode in the organic solution. The aqueous solution containing a species of interest was flowed through the narrow gap between the tube and the copper wire. A potential difference was applied at the aqueous|organic solution interface by using the copper wire and the reference electrode in the organic solution in order to realize the ion transfer at the interface, and the current due to the interfacial ion transfer was detected by the copper and platinum wires. The developed cell was evaluated adopting the transfer of an anion such as perchlorate, picrate or alkylsulphonates from the aqueous solution to 1,2-dichloroethane (used as the organic solution), and demonstrated that the anions of 10⁻⁴ mol dm⁻³ level could be determined with coefficients of variations better than 0.2% (n = 5). The applicability of the developed cell to the flow injection analysis of anions was also discussed.     

Simultaneous determination of epinephrine and uric acid at a gold electrode modified by a 2-(2,3-dihydroxy phenyl)-1, 3-dithiane self-assembled monolayer

In the present paper, the use of a gold electrode modified by 2-(2,3-dihydroxy phenyl)-1,3-dithiane self-assembled monolayer (DPDSAM) for the determination of epinephrine (EP) and uric acid (UA) was described. Initially, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge transfer rate constant, k_s, and transfer coefficient, α, were calculated. Next, the mediated oxidation of EP at the modified electrode was described. At the optimum pH of 8.0, the oxidation of EP occurs at a potential about 155 mV less positive than that of an unmodified gold electrode. The values of electron transfer coefficients (α = 0.356), catalytic rate constant (k = 1.624 × 10⁴ M⁻¹ s⁻¹) and diffusion coefficient (D = 1.04 × 10⁻⁶ cm² s⁻¹) were calculated for EP, using electrochemical approaches. Based on differential pulse voltammetry, the oxidation of EP exhibited a dynamic range between 0.7 and 500.0 μM and a detection limit (3σ) of 0.51 μM. Furthermore, simultaneous determination of EP and UA at the modified electrode was described. Finally, this method was used for the determination of EP in EP ampoule.     

Effects of the patient's age and the size of the primary lesion on the speed of shrinkage after marsupialisation of keratocystic odontogenic tumours,dentigerous cysts,and radicular cysts

Marsupialisation, by which a surgical window is created in the cavity of a cystic lesion, has been recommended to avoid the formation of a bony defect in the jaw and a reduction in a patient's quality of life. However, information about the factors that affect the reduction in the size of a cyst after marsupialisation is limited. We have studied the effects of the patient's age and the size of the primary lesion on the speed of shrinkage after marsupialisation of keratocystic odontogenic tumours (KCOTs), dentigerous cysts, and radicular cysts. The speed of shrinkage (mm²/month) was evaluated by measuring the radiolucent area on panoramic radiographs taken before and after marsupialisation for KCOT (n = 28), dentigerous cysts (n = 26), and radicular cysts (n = 18) in the mandibular molar regions. The mean duration of marsupialisation for each type of cyst was 11 (5), 8 (5), and 5 (2) months, respectively. The radiolucent area decreased linearly in the 3 types depending on the time after marsupialisation: r = −0.86 (p < 0.01), r = −0.73 (p < 0.01), and r = −0.72 (p < 0.01), respectively. The relative speed of shrinkage did not correlate with the age of the patients, though it did correlate with the size of the radiolucent area before marsupialisation in KCOT (r = 0.69, p < 0.01) and radicular cysts (r = 0.73, p < 0.01). These results suggest that the size of a cyst before marsupialisation may affect the speed of shrinkage in KCOT and radicular cysts, while the age of the patient does not.     

Electrochemical layer-by-layer modified imprinted sensor based on multi-walled carbon nanotubes and sol–gel materials for sensitive determination of thymidine

A novel electrochemical sol–gel imprinted sensor for sensitive and convenient determination of thymidine was developed. Thin film of molecularly imprinted sol–gel polymers with specific binding sites for thymidine was cast on carbon electrode by electrochemical deposition. Multi-walled carbon nanotubes (MWCNTs) were introduced for the enhancement of electronic transmission and sensitivity. The morphology and performance of the imprinted film was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and amperometric measurements (i–t) in detail. The results showed that the imprinted film exhibited high selectivity toward thymidine. The linear range is over the range from 2 to 22 μmol L⁻¹, and the linear regression equation for thymidine is I = 0.867C + 0.232 with the detection limit of 1.6 × 10⁻⁹ mol L⁻¹(S/N = 3). The imprinted sensor was successfully employed to detect thymidine in some zidovudine-tablet samples.     

Ultrasensitive determination of tungsten(VI) on pikomolar level in voltammetric catalytic adsorptive catechol-chlorate(V) system

The renewable mercury film electrode, applied for the determination of tungsten(VI) ultra traces using differential pulse catalytic adsorptive cathodic stripping voltammetry (DPCAdSV) with presence of catechol as a ligand and chlorate(V) is presented. The calibration graph obtained for W(VI) is linear from 0.025 nM (4.5 ng L⁻¹) to 130 nM (23.9 μg L⁻¹) for a preconcentration time of 30 s, with correlation coefficient of 0.9989. For the renewable mercury electrode (Hg(Ag)FE) with a surface area of 4.4 mm² the detection limit for a preconcentration time of 60 s is as low as 0.2 ng L⁻¹. The repeatability of the method at a concentration level of the analyte as low as 0.09 μg L⁻¹, expressed as RSD is 3.1% (n = 5). The proposed method was successfully applied and validated by studying the certified reference material CTA-VTL-2 and simultaneously recovery of W(VI) from spiked water samples.     

Influence of the degree of dentine mineralization on pulp chamber temperature increase during resin-based composite (RBC) light-activation

Objectives

To analyse the influence of the degree of dentine mineralization on the pulp chamber temperature increase during composite light-activation.

Methods

Dentine discs (2 mm thick) obtained from recently extracted teeth or those with extensive dentine sclerosis were analysed by FT-IR spectrometry in order to choose the two discs with the greatest difference in the degree of mineralization. A model tooth was set up with the dentine discs between a molar with the pulp chamber exposed and a crown with a standardized class II cavity. A K-type thermocouple was introduced into the molar root until it came into contact with the dentine discs and the cavity was filled with P60 resin composite. The temperature rise was measured for 120 s after light-activation began: Standard (S) 600 mW/cm²/40 s; Ramp (R) 0 → 800 mW/cm²/10 s + 800 mW/cm²/10 s; Boost (B) 850 mW/cm²/10 s and LED (L) 1.300 mW/cm²/40 s (n = 10). The same protocol was repeated after grinding the dentine discs to 1.0 and 0.5 mm thickness.

Results

The temperature increase was significantly higher in dentine with high degree of mineralization (p < 0.05). With respect to the dentine thickness, the following result was found: 2 mm < 1 mm < 0.5 mm (p < 0.05). The light-activation mode also presented significant difference as follows: S > R = L > B (p < 0.05).

Conclusions

The higher the degree of dentine mineralization the greater the increase in pulp chamber temperature. The temperature increase was influenced by the light-polymerization mode and dentine thickness.     

Comparison of in vitro erosion potentials between beverages available in the United Kingdom and the United States

Objective

Our objective was to compare the physiochemical properties and erosion potentials between beverages available in the UK and the US.

Methods

The physiochemical properties (pH, titratable acidity and fluoride concentration) and erosion potential on enamel surfaces of beverages available in the UK were compared to similar beverages from the US. Enamel windows were exposed to beverages for 25 h. Teeth were sectioned through the windows, and lesion depths were defined as the average distance between the original tooth structure and the base of demineralization.

Results

The pH was lower in UK apple juice, orange juice, Diet Pepsi^® and Sprite Zero^® (p < 0.05), and higher in UK orange soda and diet orange soda than in similar US beverages (p < 0.05). Titratable acidities were higher in UK apple juice, orange juice, orange soda, diet orange soda and Sprite^® (p < 0.01), and lower in UK Sunny D^® than in the US counterpart (p < 0.001). Fluoride concentrations were lower in UK apple juice, orange juice, Coke^®, and Diet Coke^®, Sprite^® and Sprite Zero^® (p < 0.001), and higher in UK orange soda, diet orange soda, Pepsi^® and Diet Pepsi^® than in their US counterparts (p < 0.001). Lesion depths were higher in UK apple juice, orange juice, Diet Coke^®, Sprite^® and Sprite Zero^® than in their US counterparts (p < 0.05). Lesion depths were associated with pH (p = 0.010) and country of origin (p = 0.002).

Conclusions

Under similar laboratory conditions, the physiochemical properties and erosion potentials on enamel surfaces differed between some, but not all, beverages available in the UK and the US.     

Nanofiller loading level: Influence on selected properties of an adhesive resin

Objectives

To evaluate the effect of the filler content in the cohesive strength (σ), Weibull modulus (m) and degree of conversion (DC) of an experimental adhesive system.

Methods

A HEMA/Bis-GMA/TEGDMA-based adhesive was formulated and filled with silica nanofillers in the following weight percentages (wt%): R0 = 0%; R1 = 1%; R3 = 3%; R5 = 5% and R10 = 10%. The adhesive of Adper Scotchbond Multi-Purpose (SBMP) system was used as a commercial reference. Twenty dumbbell-shaped specimens with cross-sectional area of 0.5 mm² were made per group and tensile tested with a crosshead speed of 0.5 mm/min until fracture. The cohesive strength was calculated in MPa. DC was obtained through FTIR after light curing for 25 s. Data were submitted to one-way ANOVA and Tukey's test (α = 0.05) and to Weibull analysis.

Results

Mean σ results were: R0 = 65.4 ± 8.4; R1 = 73.2 ± 8.8; R3 = 72.0 ± 8.4; R5 = 73.1 ± 9.7; R10 = 85.5 ± 13.1 and SBMP = 79.0 ± 11.0 MPa. R10 presented the highest σ, while R0 showed the lowest. R5 and SBMP did not differ significantly (p < 0.05). Weibull analysis revealed no significant difference in structural reliability between groups. The experimental adhesives presented similar results of DC, which, in turn, were significantly higher than the SBMP.

Conclusions

The addition of 10% filler in weight improves the cohesive strength of the adhesive, not interfering in the structural reliability or the degree of conversion.     

Correlation of the interleukin-29 levels in crevicular fluid and plasma with the genetic polymorphism in chronic and aggressive periodontitis patients

Objective

To assess the effect of single nucleotide polymorphism (SNP) on the Interleukin (IL-29) quantity in gingival crevicular fluid (GCF) and plasma of chronic and aggressive periodontitis patients.

Design

Patients with periodontal health (n = 30), chronic generalized periodontitis (n = 30) and generalized aggressive periodontitis (n = 30) were subjected to IL-29 quantity estimation in GCF and plasma using enzyme linked immunosorbent assay and was correlated with IL-29 SNP (rs30461) using polymerase chain reaction.

Results

IL-29 concentration in GCF and plasma was highest in aggressive periodontitis patients (114.17 ± 95.07 pg/ml and 149.69 ± 109.90 pg/ml respectively). The least concentration was found in subjects with healthy periodontium (47.50 ± 37.75 pg/ml and 54.52 ± 37.53 pg/ml) and in chronic periodontitis it was found to be 65.01 ± 41.26 pg/ml and 81.17 ± 46.23 pg/ml. The difference in the quantity of IL-29 in GCF and plasma among different groups was statistically significant (p < 0.001 and p < 0.001 respectively). rs30461 polymorphism of IL-29 analysis revealed that difference in the prevalence of A/A, A/G and G/G genotype among three groups was not statistically significant (p = 0.097).

Conclusion

Increased quantity of IL-29 in GCF and plasma of subjects with periodontitis suggests a role in pathogenesis of periodontitis and the SNP (rs30461) is not related to susceptibility to periodontitis in this population of Indian individuals.     

Voltammetric determination of concentrations of ferrocene-included nitrobenzene droplets in water

When a nitrobenzene (NB) phase came in quiescent contact with a water phase, water droplets were formed spontaneously near the oil|water interfaces (K. Aoki, M. Li, J. Chen, T. Nishiumi, Electrochem. Commn. 11 (2009) 239). We reported here quantitative data of the NB-droplets by use of UV-absorbance, dynamic light scattering (DLS) and voltammetry with a help of ferrocene. The supernatant separated spontaneously from the oil–water mixture contained 15.5 mmol dm⁻³ evaluated by UV spectra, whereas the centrifuged supernatant did 9.3 mM. The difference suggested the presence of NB-droplets, the diameter of which ranged 0.15–0.5 μm obtained by DLS. Ferrocene was dissolved deliberately in the aqueous solution and the NB solution up to saturation. The voltammograms in the ultrasonicated supernatant exhibited diffusion-controlled redox peaks of ferrocene, which should be supplied from both dissolved ferrocene and ferrocene-dissolved NB droplets. The former was 1/3.6 times of the latter by the comparison with the current of ferrocene-saturated aqueous solution. Applying the expression for the diffusion-controlled peak current of a big particle, we estimated the number concentration of NB droplet to be 1.1 × 10¹⁴ dm⁻³. This value is equivalent to the average distance, L = 2.1 μm, between neighboring two droplets, corresponding to the diffusional traveling time, L²/D = 1.3 s, which would be long enough for collision of droplets to stabilize the emulsions.     

Electrodeposited indigotetrasulfonate film onto glutaraldehyde-cross-linked poly-l-lysine modified glassy carbon electrode for detection of dissolved oxygen

The nano composited film of indigotetrasulfonate (ITS) electrodeposited onto poly-l-lysine (PLL)–glutaraldehyde (GA) (ITS/PLL–GA) was modified on glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. Composited of the proposed film was characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), electrochemical quartz crystal microbalance (EQCM), electrochemical impedance spectroscopy (EIS), and UV–vis spectrum for the absorption at λ_max at 566 nm. For the electrocatalytic reduction of dissolved oxygen, ITS/PLL–GA film modified electrodes was determined in 0.1 M acetate buffer solution (pH 5.6) by cyclic voltammetry and rotating disk electrode voltammetry. This dissolved oxygen electrochemical sensor exhibited a linear response range (from 0 to 178.4 μM, R² = 0.9949), lowest detection limit (2.2 μM), lowest overpotential at −0.09 V, high sensitivity (906 μA mM⁻¹) and relative standard deviation (RSD) for determining dissolved oxygen (n = 3) was 4.2%. In addition, the ITS/PLL–GA/GCE was advantageous in terms of its simple preparation, specificity, stability and the ability of regeneration.