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Several palladium polyselenides were prepared by the reactions of Pd2+ ions with Se x 2- (4 < x < 6) ligands in the presence of various cations. {(CH3)N(CH2CH2)3N}2[Pd(Se6)2] (I) was prepared by the methanothermal reaction of K2PdCl4, K2Se4, and {(CH3)3N(CH2CH2)N(CH3)3}I2 in a 1:3:2 molar ratio at 110 °C. Compound I crystallizes in the space group P21/c with a = 9.403(3) Å, b = 15.050(5) Å, c = 10.807(4) Å, β = 91.73(3)°, and V = 1528.7(9) Å3. (H3NCH2CH2NH2)2[Pd(Se5)2] (II) was prepared by the methanothermal reaction of PdCl2, Na2Se4, and (H3NCH2CH2NH3)Cl2 in a 1:3:1 molar ratio at 80 °C. Compound II crystallizes in the space group P21/n with a = 9.412(3) Å, b = 8.671(3) Å, c = 12.666(3) Å, β = 98.38(2)°, and V = 1023(1) Å3. The anions in [Pd(Se5)2]2- in II and [Pd(Se6)2]2- in I are polymeric and possess layered structures. The organic cations are located between the layers. K2(H3NCH2CH2NH3)2[Pd(Se4)2·2Se4] (III) was prepared by the methanothermal reaction of PdCl2, K2Se4, and (H3NCH2CH2NH3)Cl2 in a 1:3:1 molar ratio at 80 °C. Compound III crystallizes in the space group I212121 with a = 12.587(9) Å, b = 15.271(5) Å, c = 15.404(9) Å, and V = 2961(5) Å3. The [Pd(Se4)2·2Se4]6- anion in III is composed of a [Pd(Se4)2]2- three-dimensional adamantane-like framework with large cavities that are filled with the counterions and with uncoordinated Se4 2- ligands. K6[Pd(Se5)4] (IV) was prepared by the methanothermal reaction of K2PdCl4 and K2Se5 in a 1:6 molar ratio at 80 °C. The black polyhedral crystals of IV are slightly soluble in water. Compound IV crystallizes in the space group Pbcn with a = 12.427(4) Å, b = 13.777(9) Å, c = 19.190(9) Å, and V = 3285(5) Å3. The [Pd(Se5)4]6- anion is molecular and one of the most Se-rich metal polyselenides known. It has a palladium center with four dangling Se5 2- ligands around it. Being a molecular fragment, it can be regarded as a building block for extended [Pd(Se n )2]2- frameworks. Optical spectroscopic and thermal gravimetric analysis data for the compounds are reported.

The pathogenesis of a seborrheic keratosis has not been fully elucidated. In the present study, we reviewed the literature to increase the awareness of this disease among otolaryngologists and to stress the need for prompt diagnosis and treatment. This was a retrospective study in seven patients presenting with seborrheic keratoses in the ear. We included only those patients in whom keratoses were confirmed by pathology after a complete excision. In six patients, seborrheic keratoses were observed in the external auditory canal, and in one patient, they were observed in the auricle. The subtype of keratoses was classified as acanthotic in six patients; one patient had an unclassified type associated with basal cell carcinoma. Seborrheic keratoses are benign skin tumors; however, the lesions can recur after removal. Moreover, an association between seborrheic keratoses and malignant skin tumors has been reported. Therefore, otolaryngologists should consider a complete removal and histological examination of seborrheic keratoses.

Open-mouth breathing during sleep is a risk factor for obstructive sleep apnea (OSA) and is associated with increased disease severity and upper airway collapsibility. The aim of this study was to investigate the effect of open-mouth breathing on the upper airway space in patients with OSA using three-dimensional multi-detector computed tomography (3-D MDCT). The study design included a case-control study with planned data collection. The study was performed at a tertiary medical center. 3-D MDCT analysis was conducted on 52 patients with OSA under two experimental conditions: mouth closed and mouth open. Under these conditions, we measured the minimal cross-sectional area of the retropalatal and retroglossal regions (mXSA-RP, mXSA-RG), as well as the upper airway length (UAL), defined as the vertical dimension from hard palate to hyoid. We also computed the volume of the upper airway space by 3-D reconstruction of both conditions. When the mouth was open, mXSA-RP and mXSA-RG significantly decreased and the UAL significantly increased, irrespective of the severity of OSA. However, between the closed- and open-mouth states, there was no significant change in upper airway volume at any severity of OSA. Results suggest that the more elongated and narrow upper airway during open-mouth breathing may aggravate the collapsibility of the upper airway and, thus, negatively affect OSA severity.

ObjectivesThe aim of this study was to investigate optimal continuous positive airway pressure (CPAP) level, to examine the factors affecting optimal CPAP level, and to develop a predictive equation for optimal CPAP level in Korean patients with obstructive sleep apnea syndrome (OSAS).MethodsA total of 202 patients with OSAS who underwent successful manual titration for CPAP treatment were included in this study. Correlations between the optimal CPAP level and baseline data including anthropometric and polysomnographic variables were analyzed. A predictive equation for optimal CPAP level was developed based on anthropometric and polysomonographic data.ResultsThe mean optimal CPAP level in 202 patients with OSAS was 7.8±2.3 cm H2O. The mean optimal CPAP level in the mild, moderate, and severe OSAS groups was 6.0±1.3, 7.4±1.9, and 9.1±2.1 cm H2O, respectively. The apneahypopnea index (AHI) (r=0.595, P<0.001), arousal index (r=0.542, P<0.001), minimal SaO2 (r=-0.502, P<0.001), body mass index (BMI) (r=0.494, P<0.001), neck circumference (r=0.265, P<0.001), and age (r=-0.164, P=0.019) were significantly correlated with optimal CPAP level. The best predictive equation according to stepwise multiple linear regression analysis was: Optimal CPAP level (cm H2O)=0.681+(0.205×BMI)+(0.040×AHI). Forty-two percent of the variance in the optimal CPAP level was explained by this equation (R2=0.42, P<0.001).ConclusionA predictive equation for optimal CPAP level in Korean patients with OSAS was developed using AHI and BMI, which can be easily measured during the diagnostic process.