Effect of the pressureless post-sintering on the hot isostatic pressed Al2O3 prepared from the oxidized AlN powder.

The effect of the pressureless post-sintering in hydrogen on the structural and mechanical properties of the hot isostatic pressed Al2O3 prepared by oxidized AlN powder has been studied. The micrometer size AlN powder has been oxidized in air at 900° C and sintered by hot isostatic pressing (HIP) at 1700 °C, 20 MPa nitrogen atmosphere for 5 h. Pressureless sintering (PS) has been applied for all HIP sintered samples in H2 gas at 1800° C for 10 h. It has been shown that the oxidation caused a core-shell AlN/Al2O3 structure and the amount of Al2O3 increased with increasing of the oxidation time of the AlN powder. For the first time, the green samples obtained from oxidized AlN powder have been successfully sintered first by HIP followed by post-sintering by PS under hydrogen without adding any sintering additives. All post-sintered samples exhibited the main α-Al2O3 phase. Sintering in H2 caused the full transformation of AlN to α-Al2O3 phase and their better densification. Therefore, the hardness values of post-sintered samples have been increased to 17-18 GPa having apparent densities between 3.11 and 3.39 g/cm3.

Macular capillary system and ganglion cell-layer complex of the amblyopic eye with optical cohorence tomography angiography and optical cohorence tomography.

PURPOSE: To investigate the macular capillary system and ganglion cell-layer complex of the amblyopic eye with OCTA and OCT in comparison with fellow non-amblyopic eyes and a healthy control group and to examine their relationship with the severity of amblyopia. METHODS: This prospective, cross-sectional comparative study enrolled 25 amblyopic patients and 25 healthy controls. All patients and controls underwent OCTA and OCT imagining. Macular vessel densities of the Superficial Capillary Plexus (SCP) and Deep Capillary Plexus (DCP) and retinal thickness were measured by OCTA and ganglion cell layer (GCL) by OCT. RESULTS: SCP density at the fovea and parafovea was significantly lower in amblyopic eyes than in fellow eyes and control group. DCP density at the fovea was significantly lower in amblyopic eyes than fellow eyes and control group. Mean GCL thickness on OCT was 0.73 ± 0.07 µm in amblyopic eyes, 0.75 ± 0.06 µm in fellow eyes and 0.77 ± 0.06 µm in the control group. GCL volume was significantly lower in amblyopic eyes than the fellow eyes. The SCP and DCP and GCL thickness were not affected by the severity of amblyopia. CONCLUSION: Macular vessel densities of the SCP and DCP of eyes with amblyopia is lower compared to the fellow non-amblyopic eyes and the control group. The thickness of GCL was lower in amblyopic eyes than fellow eyes while the severity of amblyopia did not have any impact on these structures. Microvascular retinal structures may have been affected in the course of amblyopia development.

The perception of queen bee phenomenon in nurses; qualitative study in health sector.

OBJECTIVE: The aim of this study was to investigate how Queen bee syndrome, which is known as the mobbing behaviors of female employees from other female employees or managers, as perceived by nurses who are predominantly female workers. MATERIALS AND METHODS: The universe of the qualitative type patterned research was formed by 12 nurses between the ages of 20 and 40 who worked for at least one year in different parts of a private hospital on the Anatolian side of Istanbul province. Maximum diversity sampling method for purposes was used for sample selection. The research data were collected in the form of written recording and voice recording with an unstructured interview form, which includes the structure, gender, competence, support, conflict, and competition themes created by the researchers to evaluate the characteristics of Queen bee syndrome. Focus group interviews were held on 30 April 2018. The results were evaluated using descriptive analysis and indicator methods. RESULTS: In the study, the nurses' responses to interview questions were examined and women managers felt more emotional than men managers, and therefore they were less successful in problem-solving than men managers, but they were more successful in communication among women. The majority of nurses stated that women managers are more suitable for management in healthcare, that they are open to change, but they are not enough for men to solve the problem due to the fact that they are more concerned with the details. In addition, a significant part of the nurses, more than one female managers can cause competition and conflict in the workplace, especially women managers with similar status, said that this situation is seen more. CONCLUSIONS: The results of this study indicate that the woman is adapting to the Queen bee syndrome because of her ambition, competition, and emotional approaches, but that she has not been able to produce enough of it due to the environment.

Evaluation of fracture resistance in root canal-treated teeth restored using different techniques.

OBJECTIVE: This study aimed to evaluate the effects of different coronal restoration techniques on fracture resistance of root canal-treated mandibular premolars with mesio-occluso-distal (MOD) cavities. MATERIALS AND METHODS: A total of 105 mandibular premolars were selected and randomly distributed into seven groups (n = 15). MOD cavities were prepared except the control group. Root canal treatments were performed. Each tooth was embedded in acrylic resin. Groups were classified as follows; G1: intact teeth (control), G2: unfilled MOD cavity, G3: MOD + composite resin, G4: 10-mm-long fiber post + composite resin, G5: 5-mm-long fiber post + composite resin, G6: Ribbond in the occlusal surface + composite resin, and G7: horizontal fiber post + composite resin. Specimens were loaded using a universal testing machine until fracture occurs. Fracture loads were recorded and statistical interpretations were made (α = 0.05). RESULTS: In Groups 1, 6, and 7, the greatest fracture resistance was shown and there were no significant differences among these groups (P > 0.05). No significant differences were detected among the Groups 3, 4, and 5 (P > 0.05), whereas the fracture resistances of Groups 1, 6, and 7 were significantly greater than these three groups (P < 0.05). Group 2 had the lowest fracture resistance of all groups (P < 0.05). CONCLUSION: Usage of horizontal post or occlusal Ribbond usage increased the fracture resistance of root canal-treated premolars with MOD cavities.

Emmetropization, visual acuity, and strabismus outcomes among hyperopic infants followed with partial hyperopic corrections given in accordance with dynamic retinoscopy.

OBJECT: To record emmetropization, visual acuity, and strabismus outcomes among hyperopic infants followed with partial hyperopic corrections given in accordance with dynamic retinoscopy (DR). METHODS: Infants (3.5-12 months of age) with ≥5 D hyperopia were followed without glasses or partial hyperopic corrections prescribed according to their near dynamic accommodative abilities determined by DR responses at the initial visit and follow-ups. Refraction and binocular accommodative ability assessments were made at 3-month intervals up to the age of 1 and at 6-month intervals afterwards for a mean 35.4±2.1 months; main outcome measures being the development of esotropia, emmetropization rate, and visual acuity level after emmetropization period. RESULTS: Among 211, 146 were normal accommodators initially (Group 1). These infants were followed without treatment and none presented with strabismus. Sixty-five infants were hypo-accommodators (Group 2) and received minimum DR-based corrections. Of the 65 infants 31 (48%) developed strabismus (Group 2B). The remaining 34 constituted Group 2A. Each of the three groups showed an overall reduction of hyperopia by 0.37±0.25 days per year, 0.50±0.28 days per year, and 0.60±0.20 days per year, respectively. Visual acuity assessments among Groups 1 and 2A revealed normal values (0.2-0.0 LogMAR); among Group 2B 19% were within normal range. CONCLUSIONS: Binocular accommodative behavior at the initial visit seems to be one of the indicators for pointing out infants at risk of developing strabismus and amblyopia. Prescription of DR-based corrections to hyperopic orthotropic infants does not impede emmetropization and result in normal visual acuities after emmetropization period.

A misdiagnosed keratoacanthoma turned out to be a metastatic parotid carcinoma.

Distinguishing keratoacanthoma from well-differentiated squamous-cell carcinoma is often difficult on account of the clinical and histopathological similarities between them. Since the outcome of treatment depends on identifying the correct diagnosis and having the correct treatment on time, it is essential to differentiate keratoacanthoma and squamous-cell carcinoma as soon and accurately as possible. A paradigmatic case is herein reported. An 85 year-old female underwent total parotidectomy and ipsilateral neck dissection due to the squamous-cell carcinoma of the parotid gland. The investigations, in order to determine whether the tumour was a metastatic or a primary one, led to a misdiagnosis. A prior skin lesion, which was excised over her left cheek one year ago in another clinic, was diagnosed as keratoacanthoma. However, the histopathological revision of the specimen revealed that the lesion was in fact a squamous-cell carcinoma. Thus the parotid tumour was accepted as metastatic squamous-cell carcinoma rather than primary squamous-cell carcinoma.

Macular involvement in secondary systemic amyloidosis.

PURPOSE: A patient with subretinal and preretinal hemorrhage after secondary systemic amyloidosis due to familial Mediterranean fever is presented. METHODS: Case presentation. RESULTS: A 30-year-old woman with secondary systemic amyloidosis secondary to familial Mediterranean fever presented with painless visual loss in the right eye. The examination demonstrated multiple subretinal and preretinal hemorrhages, massive deposits which may represent amyloid material at the left macular region. After 6 months, the hemorrhages disappeared, but deposits persisted. CONCLUSIONS: The macular deposition and hemorrhage is an uncommon manifestation of secondary systemic amyloidosis secondary to familial Mediterranean fever. Further evidence is necessary to understand the nature of these deposits and their relevance to secondary systemic amyloidosis and/or familial Mediterranean fever.

Accommodative ability in exotropia: predictive value of surgical success.

PURPOSE: To evaluate the state and symmetry of accommodative response in the two eyes of patients with basic intermittent exotropia and to determine whether accommodative response is a predicting factor to the outcome of unilateral recession-resection procedures or symmetric lateral rectus recessions. METHODS: Dynamic retinoscopy was performed preoperatively on 47 patients with basic intermittent exotropia with the capacity for fusion who were undergoing a first operation for intermittent exotropia. To obtain a clinical measurement of the degree of binocular accommodative response, the monocular estimate method was used. Patients were divided into two groups: those with an "equal effective accommodative response" and those with an "unequal accommodative response" between the two eyes. Both groups received either unilateral recession-resection procedures or symmetric lateral rectus recessions. RESULTS: Thirty-two of 47 patients (68%) showed a persistent interocular difference in accommodative amplitude (asymmetric accommodation) of at least 0.75 D. Among these 32 patients with an "unequal effective accommodation," 5 of 14 patients (35.7%) receiving lateral rectus recessions had a satisfactory outcome compared with 13 of the 18 patients (72%) receiving recess/resect procedures (p = 0.039). Of the 15 patients with an "equal effective accommodation," 7 of 8 (87%) receiving recession-resection procedures had a satisfactory outcome compared with 5 of 7 patients (71%) who had lateral rectus recessions (p = 0.57). CONCLUSIONS: Data suggest that patients with an asymmetric accommodative response benefit more from recession-resection procedures. A decrease in accommodative response of the nondominant eye could be a predicting factor on the outcome of exotropia surgery.

Retinal nerve fibre layer measurements are reduced in patients with obstructive sleep apnoea syndrome.

PURPOSE: To determine the retinal nerve fibre layer (RNFL) thickness in patients with obstructive sleep apnoea syndrome (OSAS) in order to investigate the possibility of detecting early signs of glaucoma in this population. METHODS: A total of 66 consecutive patients admitted for polysomnographic evaluation of suspected OSAS. Patients underwent an overnight sleep study in an effort to diagnose and determine the severity of OSAS. Patients who had the disease were classified as having mild and severe OSAS, while patients who did not have the disease were classified as controls. All patients received physical, neurological, and ophthalmological evaluation including visual acuity, slit-lamp examination, Goldmann applanation tonometry, gonioscopy with a three mirror contact lens, and fundus examination. After these examinations, patients with glaucoma and patients who had ophthalmological and/or systemic disease known to affect RNFL thickness were excluded from the study. The RNFL thickness was assessed with a scanning laser polarimeter (Nerve Fiber Analyzer GDx, Laser Diagnostic Technologies Inc., San Diego, CA, USA). RESULTS: A total of 34 patients with obstructive sleep apnoea (19 mild, 15 severe) and 20 age-matched controls were included in the study. The thickness of RNFL was reduced in patients with OSAS compared to controls. The decrease in RNFL was found to be correlated with the severity of sleep apnoea (r=0.78, P=0.01). CONCLUSIONS: The sleep apnoea syndrome is correlated with a proportional decrease in the RNFL. Decreased ocular perfusion related to hypoxia and vasospasm associated with OSAS may cause RNFL thinning, which may precede clinically detectable glaucoma.

Effect of exogenous melatonin on ethanol-induced changes in Na(+),K(+)- and Ca(2+)-ATPase activities in rat synaptosomes.

In the present study, the effects of acute ethanol (EtOH) toxicity and of exogenous melatonin (MLT) on this toxicity were examined by measuring membrane-bound ATPases and acetylcholinesterase activities in rat synaptosomal membranes. The concentrations of plasma alpha-tocopherol and adrenal ascorbic acid (AA) were also measured. Synaptosomal Na(+),K(+)-ATPase and Ca(2+)-ATPase activities were significantly depressed in acute EtOH-intoxicated rats compared with controls, while acetylcholinesterase activity remained unaltered. Pretreatment with MLT (10 mg/kg) prior to acute EtOH administration prevented EtOH-induced inhibition of ATPases. Adrenal AA and plasma alpha-tocopherol levels were also depressed regardless of MLT pretreatment. MLT treatment alone affected neither membrane-bound enzyme activities nor tissue and blood levels of vitamins C and E. It is concluded that acute EtOH intoxication disturbs neural transport functions through the membrane-bound ATPase activity depression. Reduced AA and alpha-tocopherol levels may contribute to the neurodegenerative effects of EtOH. However, pretreatment with a high dose of MLT before EtOH administration may be beneficial to prevent EtOH-induced toxicity on ATPase-mediated neural transport functions.

Evaluation of leukocyte arylsulfatase-A activity in patients with breast cancer and benign breast disease.

This study was planned to evaluate the feasibility of using the assay of leukocyte arylsulfatase-A (AS-A) activity as a non-invasive diagnostic tool in patients with benign and malignant breast disease. The leukocyte AS-A activity of a total of 81 women was analyzed, including 28 healthy women, 29 women with benign breast disease (BBD) and 24 patients with primary breast cancer (BC). The mean leukocyte AS-A activity in patients with BBD was slightly higher (14.3%) that observed in the healthy subjects, but the difference was not statistically significant. In patients with BC the enzyme activity was significantly higher than in the healthy subjects (60.3%, P<0.05) and in the benign group (40.2%, P<0.05). In addition, since no significant differences have been observed between premenopausal patients and their controls, it is suggested that the measurement of leukocyte AS-A activity may not be a reliable test for differential diagnosis of benign and malignant proliferation in mammary glands due to the possible interfering effect of gonadal hormones on AS-A activity. In contrast, since peri- and postmenopausal BC patients have negligible or no gonadal activity function, the elevation in the activity of leukocyte AS-A in these age groups of patients may only be expected to originate from malignant proliferation. Based on our results, it is concluded that in patients in whom high leukocyte AS-A activities were observed the possibility of the presence of malignancy might also be high. Therefore, this test might be valuable as a non-invasive biochemical technique in combination with other established markers for the identification of masses in the breast.

Bilateral facial nerve paralysis with craniofacial trauma.

Bilateral facial paralysis (BFP) is a very rare condition, unlike its unilateral counterpart. Causes of BNP include a wide variety of diseases and its differential diagnosis can be challenging. We report a case of BFP secondary to craniofacial trauma, with unilateral orbitozygomatic and bilateral temporal bone fractures.

P53 overexpression in normal oral mucosa of heavy smokers.

The observation that p53 alterations are early events in the tumorigenesis of head and neck cancer and the association with cigarette smoking have prompted us to search for p53 overexpression in the oral mucosa of heavy smokers who have no overt precancerous or cancerous lesions. Formalin-fixed paraffin embedded tissue sections, obtained from oral mucosa of 30 otherwise healthy heavy smokers, were evaluated for tobacco related changes, and immunostained with a mouse monoclonal antibody p53-DO7 for p53 immunoreactivity. Histopathological evaluation revealed hyperplastic changes in twenty eight samples (93%), eight of which also demonstrated dysplastic changes. Positive immunoreaction for p53 was detected in six (20%) of the tissue samples. The study provided significant information about the frequency of hyperplasia, dysplasia, and p53 overexpression in individuals who were heavy smokers. It is suggested, also, that chemoprevention might have some impact in this particular group of individuals.

Ectopic submandibular thyroid tissue.

We reported a case of a 66 year-old male patient with a mass located in the right submandibular region. Surgical excision of the mass was performed and histologic examination revealed that the tumor was ectopic thyroid tissue. Additionally, imaging studies confirmed that the thyroid gland was found in its normal location and the patient had normal thyroid function testing. In reviewing the literature, we found submandibular thyroid tissue to be a rare entity with only 4 cases described. We discussed embryologic development of the normal thyroid gland and some explanations as to the origins of several forms of ectopic thyroid tissue, including that found in the submandibular region.

Relationship of some endogenous sex steroid hormones to leukocyte arylsulphatase A activities in pre- and postmenopausal healthy women.

This study was planned to investigate whether the physiological variations in endogenous gonadal steroid hormones during fertile period to menopause might affect the Arylsulphatase A (ARS-A) activities in leukocytes in healthy women. In premenopausal women, means of the leukocyte ARS-A activity were significantly highest at ovulatory phase, and lowest at early follicular phase. In contrast, the mean leukocyte ARS-A activity in postmenopausal women was approximately equivalent to the mean leukocyte enzyme in cycling women at early follicular phase in whom the lowest enzymatic activity was observed. The results of our study, therefore, concluded that gonadal steroid released physiologically into the bloodstream might be expected to stimulate the lysosomal system thereby leading to an enhancement in leukocyte ARS-A activity.