Child and parent preferences for the appearance of dentists with respect to personal protective equipment in paediatric dentistry

BACKGROUND

Personal protective equipment (PPE) gained particular importance during the COVID-19 pandemic.

AIM

To assess child and parent preferences for dentists' appearance concerning their PPE and to determine the relationship between the child and parent preferences.

DESIGN

A total of 250 children aged 6-12 years and their parents were enrolled in the study. Standardized pictures with different sexes, attires, eye protectors, hair protectors, masks, and gloves were shown to children and their parents separately, and they were asked to choose their preferences. The dental anxiety of the children and their parents was determined using the MCDAS_f and MDAS, respectively. Decayed, missing, and filled tooth (DMFT) indices were employed for the children.

RESULTS

Children and parents preferred a dentist of the same sex as themselves (p < .05). Anxious children preferred cartoon-printed attire, and children with low anxiety mostly preferred white coats (p = .001). Children who preferred colored coats had higher DMFT (p < .001). Statistically significant differences were found in the attire and glove preferences between children and parents (p < .001).

CONCLUSIONS

The production of white and child-friendly fluid-resistant disposable gowns should be considered. PPE with colored or cartoon print was preferred under the influence of factors that could positively affect anxiety.

Comparative evaluation of various herbal extracts on biofilms of Streptococcus mutans and Scardovia wiggsiae: An in vitro study

BACKGROUND

Owing to their strong antimicrobial properties, Helichrysum arenarium (HA), Anzer thyme (AT), and Stevia rebaudiana (SR) have been commonly used in medicine.

AIM

This study aimed to evaluate antimicrobial activities of HA, AT, and SR against S. mutans and S. wiggsiae in biofilms formed on primary teeth.

DESIGN

Fifty enamel samples were divided into two groups: mono-species biofilm and two-species biofilm. Each biofilm group was divided into five subgroups (n = 5): group 1, HA; group 2, AT; group 3, SR; group 4, CHX (positive control); and group 5, distilled water (negative control). Minimum inhibitory concentration and minimum bactericidal concentration were determined. The number of viable microorganisms was counted. The presence of microorganisms was examined using a scanning electron microscope, and mineral analysis was performed using energy-dispersive X-ray analysis.

RESULTS

In the mono-species biofilm, CHX was significantly more effective against S. mutans than other groups (p < .001). Furthermore, HA, AT, and SR groups showed significantly lower colony counts of S. mutans than distilled water (p < .05). In the two-species biofilm group, AT, SR, and CHX were significantly more effective against S. wiggsiae than distilled water (p < .05).

CONCLUSIONS

HA, AT, and SR have been suggested as effective natural alternatives to CHX against cariogenic bacteria.

Factors affecting the parental knowledge, beliefs, and attitudes towards pediatric dental X-rays

OBJECTIVES

To investigate the knowledge, beliefs, and attitudes towards pediatric dental radiography and its associated factors among Turkish parents seeking dental care for their children.

MATERIALS AND METHODS

This cross-sectional study enrolled 483 parents of children aged 6-15 years. Data were collected using the questionnaire including socio-demographic characteristics, knowledge, beliefs, and attitudes based on The Health Belief Model and planned behavior theory. Descriptive, bivariate, and multivariate statistics were performed.

RESULTS

More than half of parents had correct knowledge on their rights to access health information, the radiation risk and exposure from dental X-rays, children's vulnerability to radiation, and using lead apron. Most parents (70.4%) perceived dental X-rays as valuable. They had limited knowledge regarding the permanent damage and negative attitudes regarding its safety and goodness. There were positive correlations between knowledge-attitudes, knowledge-perceived benefits, and attitudes-perceived benefits (all p values < 0.01). Having a previous dental X-ray (p = 0.014) and not having parents' information needs (p = 0.007) were associated with higher attitudes. Increasing education levels, having a educational need and higher perceived benefit were found to be predictors of higher parental knowledge.

CONCLUSION

Turkish parents had some knowledge and positive attitudes towards pediatric dental X-rays but not at optimum levels. Parents' education levels, information needs, and beliefs were the most important factors affecting parental knowledge. Attitudes towards radiation safety and goodness should be improved.

CLINICAL RELEVANCE

These findings may provide useful insight to clinicians when developing theory-driven health education interventions on pediatric dental X-rays and identifiying the parents with low knowledge.

Performance and analysis of four pediatric mortality prediction scores among critically ill children: A multicenter prospective observational study in four PICUs

OBJECTIVE

We aimed to evaluate and compare the prognostic performance of common pediatric mortality scoring systems (the Pediatric Index of Mortality 2 [PIM2], PIM3, Pediatric Risk of Mortality [PRISM], and PRISM4 scores) to determine which is the most applicable score in our pediatric study cohort.

METHODS

This prospective observational multicenter cohort study was conducted in four tertiary-care pediatric intensive care units (PICUs) in Turkey. All children, between 1 month and 16 years old, admitted to the participating PICUs between October 1, 2019, and March 31, 2020, were included in the study. Discrimination between death and survival was assessed by area under the receiver operating characteristic plot (AUC) for each model. The Hosmer-Lemeshow goodness-of-fit (GOF) test was used to assess the calibration of the models, RESULTS: A total of 570 patients (median age 35 months) were enrolled in the study. The observed mortality rate was 8.2% (47/570). The standardized mortality ratio (SMR) of PIM2, PIM3, PRISM, and PRISM4 with 95% confidence interval (CI) were 0.94 (0.68-1.23), 1.27 (0.93-1.68), 0.86 (0.63-1.13), and 1.5 (1.10-1.97), respectively. The AUC with 95% CI was 0.934 (0.91-0.96) for PIM2, 0.934 (0.91-0.96) for PIM3, 0.917 (0.88-0.95) for PRISM, and 0.926 (0.88-0.97) for PRISM4 models. The Hosmer-Lemeshow test showed that the difference between observed and predicted mortality by PIM3 (p = 0.003) and PRISM4 (p = 0.008) was statistically significant whereas PIM2 (p = 0.28) and PRISM (p = 0.62) showed good calibration.

CONCLUSION

The overall performance of (both discrimination and calibration) PRISM and PIM2 scoring systems in Turkish pediatric patients aged 1 month to 16 years was accurate and had the best fit for risk groups according to our study. Although PIM3 and PRISM4 have good discriminatory power, their calibration was very poor in our study cohort.

Validity and reliability of the Turkish version of the Child Perceptions Questionnaire 8-10

BACKGROUND

A reliable measurement tool is needed to gain more knowledge about Turkish children's oral health status that affects the quality of life.

AIM

To develop a translated version of CPQ_8-10 into Turkish language and evaluate its reliability, validity, and reproducibility.

DESIGN

The intra-class correlation coefficient (ICC) was used for the test-retest reliability in the 50 children. For the internal consistency, 418 children aged 8-10 years were evaluated using Cronbach's alpha Coefficient. Construct validity and discriminant validity were calculated using Spearman's correlation analysis, and exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) was also employed.

RESULTS

The mean CPQ_8-10 score was 13.3 ± 9.2. The translated Turkish version of CPQ_8-10 showed high test-retest reliability (ICC = 0.90) and internal consistency (Cronbach's alpha = 0.82). A statistically significant correlation was observed between the scores of the CPQ_8-10 and oral health and overall well-being, which revealed good construct validity (r = 0.50; P < .001 and r = 0.47; P < .001, respectively). Seven factors identified from EFA were statistically verified using CFA. Discriminant validity was supported by significant differences between CPQ and OHIS scores (P < .001).

CONCLUSIONS

The translated version of CPQ_8-10 to the Turkish language is reliable, valid, and reproducible for use in the Turkish culture in this age group.

Can lavender oil inhalation help to overcome dental anxiety and pain in children? A randomized clinical trial

Aromatherapy with essential oils can be used to relieve children. The aim of this study was to evaluate the correlations between psychological and physiologic findings after lavender oil inhalation among children assigned to undergo tooth extraction. A total of 126 children aged between 6 and 12 years were enrolled in the study. The groups were randomly divided into control and lavender groups. The lavender group inhaled 100% lavender oil for 3 min before the interventions, the control group received no prior application. Psychological assessments were made using face image scale (FIS), Face, Legs, Activity, Cry, Consolability (FLACC) and Wong-Baker pain rating scale (WBS). Physiologic changes were assessed using vital signs evaluations. All parameters were noted prior to applications, after inhalation, anesthesia injection, and tooth extraction. The lavender group showed significant lower anxiety and pain scores after tooth extraction (p < 0.05). Significantly lower levels of blood pressures and a significant pulse rate drop were found after inhalation in the lavender group. A statistically significant increase in heart rate was observed after anesthesia injection and tooth extraction in the control group (p < 0.05).Conclusion: Lavender oil can be preferred as a treatment of choice in routine pediatric dentistry.Trial registration number: NCT04115891 (Lavender Oil Inhalation Help to Overcome Dental Anxiety Among Children)What is Known:• Dental anxiety is the most common factor that causes children to have difficulty with the dentist and their parents during treatment.• Aromatherapy with essential oils can be used to relieve children.What is New:• Aromatherapy with lavender oil relieves the child by reducing the level of anxiety and facilitates dental treatment.• During surgical procedures such as local anesthesia and tooth extraction, lavender oil inhalation decreases pain levels of children.

The effects of cavity disinfection on the nanoleakage of compomer restorations: an in vitro study

Purpose:

Cavity disinfection, in addition to routine caries removal methods, is recommended to eliminate the microorganisms. The aim of this study was to compare the effect of various systems Er,Cr:YSGG lasers, diode lasers and FotoSan and agents Corsodyl; Cervitec and Cervitec Plus and Fluor Protector—on the nanoleakage of compomer restorations when used for cavity disinfection.

Materials and methods:

A total of 40 intact human deciduous molar teeth containing Black V cavities (3×2×1.5 mm) on the buccal and lingual surfaces parallel to the cementoenamel junction were randomly divided into 8 groups according to the cavity disinfection methods. The antibacterial agents and systems were applied according to the manufacturer’s instructions. Restorations were completed using a compomer. The restored teeth were then subjected to thermocycling for 500 cycles in a water bath at 5°C and 55°C with a dwell time of 30 seconds. After the thermocycling procedures, 1-mm sticks were obtained from the center of each cavity to prepare for the nanoleakage test. After the teeth were sectioned, they were immersed in 50 wt % ammoniacal silver nitrate solution for 24 hours and dipped in photo-developing solutions for 8 hours with fluorescent light irradiation. The samples were examined under a scanning electron microscope (SEM). The non-parametric Kruskal-Wallis and Mann-Whitney U test (p<0.05) were applied.

Results:

The Er,Cr:YSGG laser group showed significantly less nanoleakage than all of the tested groups (p<0.01). The diode laser, Fluor protector and FotoSan groups showed similar nanoleakage to that of the control group (p>0.05). The Corsodyl (p<0.01) and Cervitec (p<0.001) groups showed significantly higher nanoleakage than the control group.

Conclusion:

Er,Cr:YSGG laser irradiation which showed lower nanoleakage scores from either control or tested groups can be recommended for cavity disinfection Additionally, a diode laser and FotoSan, which have antibacterial effects and no negative effect on leakage, can be used for cavity disinfection.

Comparison of different femoral fixation implants and fit techniques for tunnel widening and clinical outcome in ACL reconstruction using hamstring autograft

PURPOSE

The purpose of the current study is to investigate in different femoral fixation devices whether tight (undersize drilled) fit technique decreases the tunnel widening and improves the clinical outcome compared to conventional technique in ACL reconstruction using hamstring tendon autograft.

METHODS

93 patients, who underwent Arthroscopic ACL reconstruction whether cortical-cancellous suspension (CP) or cortical suspension (BF) used as fixation device for the hamstring tendon autograft, were included in the study. The cases also grouped as undersize drilled (tight fit) and normal drilled (normal fit) according to their autograft size. There was no difference in demographic data of these four subgroups (CP-TF, CP-NF, BF-TF, and BF-NF) preoperatively.

RESULTS

The patients, who had been followed for at least 2 years were included in the study. They were looked for their clinical outcome (Lysholm and IKDC scoring), tunnel widening (on AP and lateral radiographs), and also anterior translation. The BF-TF subgroup showed significantly the best clinical results compared to other three subgroups. There was no difference between BF-TF, CP-TF, and CP-NF in terms of tunnel widening.

CONCLUSION

Button fixation of femoral side in ACL reconstruction surgery has good clinical outcome and lower complication rate. Undersize drilling might be preferred in button fixation in order to reduce TW and improve stability and clinical satisfaction.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Antibacterial effects of fluoride varnish compared with chlorhexidine plus fluoride in disabled children

PURPOSE

To evaluate the effects of fluoride varnish vs a combination of chlorhexidine-thymol varnish plus a gel containing chlorhexidine and fluoride on oral hygiene and caries prevention in disabled children.

MATERIALS AND METHODS

Ninety patients aged 3-17 years who were treated under general anaesthesia were randomly assigned into three groups as follows: group 1: Fluor Protector (0.1% fluoride varnish); group 2: Cervitec Plus (1% chlorhexidine- 1% thymol varnish) + Cervitec Gel (0.2% chlorhexidine-0.2% sodium fluoride); group 3: control (toothbrushing only). Mutans streptococci (MS) and lactobacilli (LB) levels, visible plaque index (VPI) and gingival bleeding index (GBI) were evaluated at four stages: T0, before general anaesthesia; T1, one month after treatment; T2, six months after treatment; T3, twelve months after treatment. The data were evaluated using Kruskal-Wallis and Mann-Whitney U-tests (P < 0.05).

RESULTS

Groups 1 and 2 showed significantly lower scores than group 3 for all parameters at T1 and T2. No statistically significant difference was detected among any of the the groups at T3 (P > 0.05).

CONCLUSION

The use of materials that include both fluoride and chlorhexidine as routine treatment of children with disability may increase the success of restorations by improving oral hygiene, reduce the need for future restorative treatments and thus the need for general anaesthesia.

The effect of an erbium, chromium: yttrium-scandium-gallium-garnet laser on the microleakage and bond strength of silorane and micro-hybrid composite restorations

Objective:

The aim of this in vitro study was to compare the microleakage and bond strength of Class V silorane-based and universal micro-hybrid composite restorations prepared either with diamond bur or with an erbium, chromium: yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser.

Materials and Methods:

A total of 160 molar teeth were used for microleakage assessment and shear bond strength (SBS) test. The specimens were prepared using either diamond bur or 3 W-, 4 W- and 5 W-20 Hz Er, Cr:YSGG laser irradiation. All specimens were subjected to thermocycling (500 times at 5 ± 2°C to 55 ± 2°C, dwell time 15 s and transfer time 10 s). Microleakage was assessed using a 0.5% basic-fuchsin solution. The bond strengths were determined using a microtensile tester at a crosshead speed of 0.5 mm/min. The Kruskal Wallis test was used for the analysis of microleakage and a one-way analysis of variance test was used to analyze the SBS (P < 0.05).

Results:

No statistically significant differences were found (P > 0.05) between Er, Cr:YSGG laser and bur preparation methods regarding microleakage and bond strength values.

Conclusion:

Irradiation with Er, Cr:YSGG laser was confirmed to be as effective as conventional methods for preparing cavities before adhesive restorations.

Factors influencing quantitative liquid (scanning) transmission electron microscopy

An overview of beam–sample interactions identified for changing imaging and experimental conditions using a visual approach.

The LMA CTrach™ in morbidly obese and lean patients undergoing gynecological procedures: a comparative study

PURPOSE

The tracheas of obese patients may be more difficult to intubate than those of normal-weight patients. The aim of this study was to compare the airway management quality in morbidly obese and lean patients with use of the LMA CTrach.

METHODS

After Ethics Committee approval, 60 adult patients (30 morbidly obese patients with body mass index >40 kg/m² and 30 lean patients with body mass index <30 kg/m²) scheduled to undergo gynecological surgery were enrolled in this prospective study. The induction of anesthesia was standardized using propofol, fentanyl, and rocuronium. Ventilation and intubation success rates, time taken to achieve successful ventilation, and intubation through the CTrach and airway complications were recorded.

RESULTS

The CTrach was successfully inserted and adequate ventilation through the CTrach was achieved in 59 patients (98%). Only 1 patient in the lean group was not able to ventilate through the CTrach. We were successful in endotracheal intubation, either under vision or blind, in 56 patients (93%). We were able to view the larynx in 51 patients (85%). Total intubation time was significantly longer in morbidly obese patients, 69 (311) s, than in lean patients, 33 (107) s [median (range)] (P < 0.001).

CONCLUSIONS

We concluded that the time to intubate the trachea in obese patients was significantly longer than in lean patients when the LMA CTrach was used.

Anticandidal activity of endemic Salvia potentillifolia Boiss. and Heldr . ex Bentham and Origanum hypericifolium Schwartz and P.H. Davis in Turkey

This study established baseline data on lytic anticandidal activities of endemic species Origanum hypericifolium and Salvia potentillifolia naturally distributed in Denizli and its environment. Stream distillation was used to isolate the unfatty polar part and clinical isolated Candida spp. strains were subcultured to sabouraud dextrose agar. Lytic anticandidal activities of unfatty polar parts were evaluated by enzyme-linked calorimetric method against 93 clinical isolates belonging to Candida albicans, C. tropicalis, C. glabrata, C. krusei, C. Kefyr, and C. parapsilosis. As a result, two (2.15%) strains of C. glabrata among tested pathogenic 93 clinical isolates of Candida strains were found to be sensitive to S. potentillifolai. However, each strain of C. albicans and C. tropicalis was found to be sensitive to O. hypericifolium. Results indicated that O. hypericifolium and S. potentillifolia had a potential of being used in food and medicine because of their anticandidal activity.

Omega-3 fatty acid application reduces yolk and plasma cholesterol levels in Japanese quails

The aim of this study was to determine the effects of fish oil, rich in omega-3 fatty acids, on the cholesterol levels in egg yolk and plasma in Japanese quail. Additionally, the effects of these fatty acids on selected biochemical parameters, and yolk and quail weights were investigated. Thirty healthy laying Japanese quails were divided into two groups including control and omega-3 fatty acid treated group. Fish oil capsules were administrated orally to the quails in the omega-3 treated group every other day for 3 weeks. Yolk cholesterol level was found to be significantly lower in the omega-3 treated group compared to the control. Plasma cholesterol levels were lower; plasma calcium levels were higher at 3rd week in omega-3 fatty acid treated group than those in control. On the other hand, plasma phosphorus and glucose levels in omega-3 fatty acid group were significantly lower at 3rd week than those at the beginning of experiment. In conclusion, it was found that orally supplemented omega-3 fatty acid reduced the levels of cholesterol in egg yolk and plasma in quails.

The value of fine-needle aspiration cytology in salivary gland lesions, 1994-2004

OBJECTIVE

Fine-needle aspiration cytology (FNAC) of the salivary gland is a commonly accepted, sensitive and specific technique in the diagnosis of both neoplastic and nonneoplastic lesions of the salivary gland. The aim of this study was to investigate the efficacy of FNAC of salivary gland lesions and to decide whether the radiologist could perform it or not.

METHODS

We aspirated 162 salivary gland lesions of 56 patients undergoing biopsy and excision. A cytopathologist and a surgical pathologist made histopathological and cytological examinations in a blinded fashion.

RESULTS

In the present study, among the FNAC performed in 162 patients with salivary gland masses, 15 (9%) were inadequate, and the remaining 147 were diagnostic. Of the 162 cases, 56 (35%) were also checked histologically. With FNAC there were 89 (55%) nonneoplastic and 58 (36%) neoplastic lesions. With FNAC 45 of the neoplastic lesions were benign and 13 malignant tumors. When cytohistopathological correlation was performed, the overall accuracy in diagnosing benign and malignant lesions was 91 and 78%, respectively, except for 2 malignant lymphoma cases. The sensitivity and specificity for benign and malignant lesions were 72 and 100%, respectively. The diagnostic sensitivity for all neoplastic and nonneoplastic lesions was 84% and the specificity 92%. There was 1 false-positive result, in which a nonneoplastic lesion was misdiagnosed as a Warthin's tumor. Fifteen (26%) cases were false-negative, 12 of which were undefined.

CONCLUSION

FNAC is a useful and reliable tool in the diagnosis of salivary gland masses when performed by a radiologist or a clinician. There are no contraindications, and complications are minimal.

Nanoscale scanning transmission electron tomography

Electron tomography enables the study of complex three-dimensional objects with nanometre resolution. In materials science, scanning transmission electron microscopy provides images with minimal coherent diffraction effects and with high atomic number contrast that makes them ideal for electron tomographic reconstruction. In this study, we reviewed the topic of scanning transmission electron microscopy-based tomography and illustrated the power of the technique with a number of examples with critical dimensions at the nanoscale.

Effects of Perfusion Solutions on Kidney Ischemia-Reperfusion Injury in Pigs

During ischemia-reperfusion, free oxygen radicals which directly affect renal cells may cause delayed graft function. We investigated whether there was a difference regarding antioxidant enzyme content between use of Ringer's lactate (RL) versus University of Wisconsin (UW) perfusion solutions in kidney transplantation. Ischemia was achieved by clamping the renal pedicle for 20 minutes followed by perfusion with either solution for 20 minutes and reperfusion for another 20 minutes. A parenchymal biopsy was taken before and after the ischemia, perfusion, and reperfusion (IPR) process. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) were investigated in the biopsy specimens. We used paired t tests within groups and t tests for comparisons between groups. The results were expressed as mean values +/- SEM with P < .05 accepted as statistically significant. After IPR, SOD, GPx, and MDA were decreased in all groups: only GPx (P = .001) and MDA (P = .04) for the RL group and SOD (P = .001) and MDA (P = .05) for the UW group were statistically significant. In the control group, we did not observe any difference (P > .05). Comparisons between groups did not reveal differences (P > .05). In our study, no difference was observed between RL and UW regarding their effects on antioxidant enzymes following renal I/R injury in pigs. More investigations are needed to evaluate graft function in this setting.

Embedded Nanostructures Revealed in Three Dimensions

Nanotechnology creates a new challenge for materials characterization because device properties now depend on size and shape as much as they depend on the traditional parameters of structure and composition. Here we show that Z-contrast tomography in the scanning transmission electron microscope has been developed to determine the complete three-dimensional size and shape of embedded structures with a resolution of approximately 1 cubic nanometer. The results from a tin/silicon quantum dot system show that the positions of the quantum dots and their size, shape, structure, and formation mechanism can be determined directly. These methods are applicable to any system, providing a unique and versatile three-dimensional visualization tool.

Distortion and segregation in a dislocation core region at atomic resolution

The structure of an isolated, Ga terminated, 30 degree partial dislocation in GaAs:Be is determined by high resolution transmission electron microscopes and focal series reconstruction. The positions of atomic columns in the core region are measured to an accuracy of better than 10 pm. A quantitative comparison of the structure predicted by an ab initio electronic structure total energy calculation to the experiment indicates that theory and experiment agree to within 20 pm. Further analysis shows the deviations between theory and experiment appear to be systematic. Electron energy loss spectroscopy establishes that defects segregate to the core region, thus accounting for the systematic deviations.

Role of oxygen at screw dislocations in GaN

Here we report the first direct atomic scale experimental observations of oxygen segregation to screw dislocations in GaN using correlated techniques in the scanning transmission electron microscope. The amount of oxygen present in each of the three distinct types of screw dislocation core is found to depend on the evolution and structure of the core, and thus gives rise to a varying concentration of localized states in the band gap. Contrary to previous theoretical predictions, the substitution of oxygen for nitrogen is observed to extend over many monolayers for the open core dislocation.

Comparison of simulation methods for electronic structure calculations with experimental electron energy-loss spectra

The electronic structure of hexagonal GaN is studied using two simulation techniques in order to develop a method to interpret the fine-structure of an experimental nitrogen K-edge electron energy loss spectrum obtained using a scanning transmission electron microscope. The application of these simulation methods to the bulk spectrum is a necessary first step in developing a fundamental understanding of the effect of changes in the electronic structure on the properties of defects. It is found here that both of the techniques used, multiple scattering (MS) and density functional theory (DFT), produce excellent agreement with the experimental bulk spectrum. The MS method is limited in accuracy but efficient in time, while the DFT method is more accurate but time consuming. Through the combination of these methods, experimental energy loss spectra can be readily understood, and a means to unravel the complexities of the electronic structure can be determined.

Treatability of a simulated disperse dye-bath by ferrous iron coagulation, ozonation, and ferrous iron-catalyzed ozonation

Dyeing and finishing of textile yarns and fabrics are extremely important processes in terms of both quality and environmental concerns. Among the commercial textile dyes, particularly disperse dyestuffs are of environmental interest because of their widespread use, their potential for formation of toxic aromatic amines and their low removal rate during aerobic waste treatment as well as advanced chemical oxidation. Thus, in the present paper ferrous iron coagulation, ozonation and ferrous iron-catalyzed ozonation were employed at varying pH (3-13) and Fe(II)-ion doses (0.09-18mM) for the treatment of a simulated disperse dye-bath (average initial apparent color as absorbance at 566nm=815.4m(-1); COD(0)=3784mgl(-1); TOC(0)=670mgl(-1); BOD(5,0)=58mgl(-1)) that more closely resembled an actual dyehouse effluent than an aqueous disperse dye solution. Coagulation with 5000mgl(-1) FeSO4-7H2O (18mM Fe(2+)) at pH 11 removed up to 97% color and 54% COD, whereas oxidation via ozonation alone (applied ozone dose=2300mgl(-1)) was only effective at pH 3, resulting in 77% color and 11% COD removal. Fe(II)-ion-catalyzed ozonation (3.6mM Fe(2+) at pH 3; Fe(2+):O3 molar ratio 1:14) eliminated 95% color and 48% COD and appeared to be the most attractive option among the investigated chemical treatment methods as for its applicability at the natural acidic pH of the disperse dye-bath effluent and at relatively low Fe(2+)-ion doses as compared to ferrous sulfate coagulation. However, no TOC reduction was observable for ozonation and catalytic ozonation at the investigated reaction conditions (14gl(-1) O3 at pH 3). An average six-fold enhancement in the biodegradability parameter of the synthetic dye wastewater expressed in terms of the BOD(5)/COD ratio could be achieved by the investigated chemical treatment methods.

Application of atomic scale STEM techniques to the study of interfaces and defects in materials

Incoherent imaging and analysis techniques in the scanning transmission electron microscope (STEM) provide the potential to map changes in structure, composition and bonding that occur at materials interfaces and defects on the fundamental atomic scale. Such comprehensive characterization capabilities permit a detailed analysis of the structure-property relationships of interfaces and defects to be performed. In this paper, we discuss the resolution limits of such techniques in the JEOL 2010F STEM/TEM operating both under standard conditions and at elevated temperatures. Examples of the use of such techniques to quantify the atomic scale defect chemistry at interfaces and defects in perovskite oxides, the growth and structure of II-VI and III-V quantum dots and the electronic structure of threading dislocations in GaN will also be presented.

Homogenous and heterogenous advanced oxidation of two commercial reactive dyes

Two commercial reactive dyes, the azo dye Reactive Black 5 and the copper phythalocyanine dye Reactive Blue 21, have been treated at a concentration of 75 mg l(-1) by titanium dioxide mediated photocatalytic (TiO2/UV), dark and UV-light assisted Fenton (Fe2+/H2O2) and Fenton-like (Fe3+/H2O2) processes in acidic medium. For the treatment of Reactive Black 5, all investigated advanced oxidation processes were quite effective in terms of colour, COD as well as TOC removal. Moreover, the relative growth inhibition of the azo dye towards the marine algae Dunaliella tertiolecta that was initially 70%, did not exhibit an increase during the studied advanced oxidation reactions and complete detoxification at the end of the treatment period could be achieved for all investigated treatment processes. However, for Reactive Blue 21, abatement in COD and UV-VIS absorbance values was mainly due to the adsorption of the dye on the photocatalyst surface and/or the coagulative effect of Fe3+/Fe2+ ions. Although only a limited fraction of the copper phythalocyanine dye underwent oxidative degradation, 47% of the total copper in the dye was already released after 1 h photocatalytic treatment.

Partial oxidation of reactive dyestuffs and synthetic textile dye-bath by the O3 and O3/H2O2 processes

Ozonation and O3/H2O2 oxidation of reactive dyestuffs and simulated textile dye-bath were investigated. Effects of reaction pH, initial dye concentration, H2O2 concentration and assisting chemicals on treatment efficiency were examined. We found considerable improvement in COD and colour removal rates at pH = 11, that was almost the actual pH of the prepared textile wastewater, whereas in particular increasing the initial dyestuff concentration had an adverse effect upon oxidation rates. Removal of colour, COD and TOC were found to be fairly sensitive to the introduction of soda that is frequently applied as an auxiliary chemical during the reactive dyeing process. The addition of H2O2 had negligible effect on COD removal efficiency and decolorization rate compared to ozonation alone at different pH values. Accordingly it can be inferred that the theoretically expected effect of OH radical scavengers (e.g. carbonate, chloride) present in the synthetic dye-bath as well as introduced radical formation promoters (e.g. H2O2, OH-) were probably hidden due to the complexity of the synthetic wastewater matrix. Biodegradability of the ozonated dye-bath was accelerated by a factor of three corresponding to a 233% relative enhancement. The inhibition of the oxygen uptake rate decreased from 91% to 75% within only 5 min treatment time.

Photochemical treatment of simulated dyehouse effluents by novel TiO2 photocatalysts: experience with the thin film fixed bed (TFFB) and double skin sheet (DSS) reactor

This study has been undertaken to provide a rather practical assessment of the heterogeneous photocatalytic treatment of two simulated reactive dye-bath effluents via three commercial TiO2 types (Degussa P25, Millennium PC 500 and Sachtleben Mikroanatas), which were employed in fixed film and suspended photochemical reactor configurations. The obtained results have clearly revealed that the inherent advantage of eliminating a proceeding photocatalyst separation step did not justify the significantly lower treatment performance of the thin film fixed bed (TFFB) reactor, which is directly reflected in the values obtained for percent photonic efficiencies (% zeta), first-order decolourisation rate constants (kd) and the collector area requirements per unit of mineralisation rate (CA/M), as compared to the more recently developed suspended double skin sheet (DSS) photoreactor. Generally speaking, Degussa P25 was found to be most efficient among the investigated TiO2 photocatalyst types.

Fibrolamellar hepatocellular carcinoma "it is not a ordinary case for Mediterranean countries"

The fibrolamellar variant of hepatocellular carcinoma (HCC) is an uncommon tumour with distinctive clinical and histological features. Although the first case of fibrolamellar hepatocellular carcinoma (FI-HCC) was described by Edmondson in 1956, and later confirmed in five patients by Peters, the majority of reports followed those of Berman et al. and Craig et al. A case of FI-HCC, which is rarely diagnosed in Mediterranean countries including Turkey, is presented in the following report.