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Barium zirconate (BaZrO3, BZO), which exhibits superior mechanical, thermal, and chemical stability, has been widely used in many applications. In dentistry, BZO is used as a radiopacifier in mineral trioxide aggregates (MTAs) for endodontic filling applications. In the present study, BZO was prepared using the sol–gel process, followed by calcination at 700–1000 °C. The calcined BZO powders were investigated using X-ray diffraction and scanning electron microscopy. Thereafter, MTA-like cements with the addition of calcined BZO powder were evaluated to determine the optimal composition based on radiopacity, diametral tensile strength (DTS), and setting times. The experimental results showed that calcined BZO exhibited a majority BZO phase with minor zirconia crystals. The crystallinity, the percentage, and the average crystalline size of BZO increased with the increasing calcination temperature. The optimal MTA-like cement was obtained by adding 20% of the 700 °C-calcined BZO powder. The initial and final setting times were 25 and 32 min, respectively. They were significantly shorter than those (70 and 56 min, respectively) prepared with commercial BZO powder. It exhibited a radiopacity of 3.60 ± 0.22 mmAl and a DTS of 3.02 ± 0.18 MPa. After 28 days of simulated oral environment storage, the radiopacity and DTS decreased to 3.36 ± 0.53 mmAl and 2.84 ± 0.27 MPa, respectively. This suggests that 700 °C-calcined BZO powder has potential as a novel radiopacifier for MTAs. [ABSTRACT FROM AUTHOR]

Barium titanate (BaTiO3, BTO), conventionally used for dielectric and ferroelectric applications, has been assessed for biomedical applications, such as its utilization as a radiopacifier in mineral trioxide aggregates (MTA) for endodontic treatment. In the present study, BTO powders were prepared using the sol-gel process, followed by calcination at 400–1100 °C. The X-ray diffraction technique was then used to examine the as-prepared powders to elucidate the effect of calcination on the phase composition and crystalline size of BTO. Calcined BTO powders were then used as radiopacifiers for MTA. MTA-like cements were investigated to determine the optimal calcination temperature based on the radiopacity and diametral tensile strength (DTS). The experimental results showed that the formation of BTO phase was observed after calcination at temperatures of 600 °C and above. The calcined powders were a mixture of BaTiO3 phase with residual BaCO3 and/or Ba2TiO4 phases. The performance of MTA-like cements with BTO addition increased with increasing calcination temperature up to 1000 °C. The radiopacity, however, decreased after 7 days of simulated oral environmental storage, whereas an increase in DTS was observed. Optimal MTA-like cement was obtained by adding 40 wt.% 1000 °C-calcined BTO powder, with its resulting radiopacity and DTS at 4.83 ± 0.61 mmAl and 2.86 ± 0.33 MPa, respectively. After 7 days, the radiopacity decreased slightly to 4.69 ± 0.51 mmAl, accompanied by an increase in DTS to 3.13 ± 0.70 MPa. The optimal cement was biocompatible and verified using MG 63 and L929 cell lines, which exhibited cell viability higher than 95%. [ABSTRACT FROM AUTHOR]

The hydrophobic hydration of dimethylsulfoxide (DMSO)/D[sub 2]O was explored using a combination of the high-pressure method and ab initio calculations. The frequencies of the C-H stretching vibration of DMSO increase as the mole fraction of D[sub 2]O increases, while no appreciable changes in spectral shapes are observed upon dilution. Interestingly, the infrared spectra of DMSO/D[sub 2]O observed under high-pressure exhibits dramatic changes, while the new spectral features locating at ∼2942 and ∼3033 cm[sup -1] appear. The spectral changes were attributed to the combined effect of C-H-O hydrogen bonding between C-H in DMSO and oxygen atom in D[sub 2]O, a phase change, pressure increase, etc. Ab initio calculation results, forecasting the frequency shift of the C-H stretching vibration as C-H-O is interacting via hydrogen bonding, are discussed. The reorganization of the hydrogen-bond network or geometry may be responsible for spectral changes as the pressure was elevated. [ABSTRACT FROM AUTHOR]

Among the various phases of bismuth oxide, the high temperature metastable face-centered cubic δ phase attracts great attention due to its unique properties. It can be used as an ionic conductor or an endodontic radiopacifying material. However, no reports concerning tantalum and bismuth binary oxide prepared by high energy ball milling and serving as a dental radiopacifier can be found. In the present study, Ta2O5-added Bi2O3 composite powders were mechanically milled to investigate the formation of these metastable phases. The as-milled powders were examined by X-ray diffraction and scanning electron microscopy to reveal the structural evolution. The as-milled composite powders then served as the radiopacifier within mineral trioxide aggregates (i.e., MTA). Radiopacity performance, diametral tensile strength, setting times, and biocompatibility of MTA-like cements solidified by deionized water, saline, or 10% calcium chloride solution were investigated. The experimental results showed that subsequent formation of high temperature metastable β-Bi7.8Ta0.2O12.2, δ-Bi2O3, and δ-Bi3TaO7 phases can be observed after mechanical milling of (Bi2O3)95(Ta2O5)5 or (Bi2O3)80(Ta2O5)20 powder mixtures. Compared to its pristine Bi2O3 counterpart with a radiopacity of 4.42 mmAl, long setting times (60 and 120 min for initial and final setting times) and 84% MG-63 cell viability, MTA-like cement prepared from (Bi2O3)95(Ta2O5)5 powder exhibited superior performance with a radiopacity of 5.92 mmAl (the highest in the present work), accelerated setting times (the initial and final setting time can be shortened to 25 and 40 min, respectively), and biocompatibility (94% cell viability). [ABSTRACT FROM AUTHOR]

A 35-day-old male infant was scheduled for bilateral inguinal herniorrhaphy. No history of recent upper airway infection or other reactive respiratory disease was noted before anesthesia. Breath holding was noted immediately after laryngeal mask airway (LMA) insertion. Removal of the LMA and positive pressure ventilation via face mask did not solve the problem. On suspicion of laryngospasm, tracheal intubation facilitated by muscule relaxant was performed. However, when the patient was ventilated, high airway pressure, absence of chest wall movement and elevated end-tidal CO2 were noted. Despite visual confirmation of correct placement of tracheal tube, oxygen desaturation and bradycardia developed rapidly. After deepening the inhalational anesthesia of sevoflurane and concomitant administration of intravenous lidocaine, the patient's respiratory condition turned for the better and became compliable. Respiratory dysfunction may be caused by severe bronchospasm induced by placement of the LMA. The pathophysiology and risk factors of bronchospasm related to the LMA placement are discussed in the text.

Background: This study was undertaken to evaluate the long-term effect of a peripheral neuropathic pain model, chronic constriction injury (CCI) of the sciatic nerve, through analyses of electrophysiologic change, sciatic nerve function, and pain behavior., Methods: CCI of the sciatic nerve was induced in twelve rats as described by Bennett and Xie. Three parameters were monitored: spinal somatosensory evoked potential (SSEP) elicited by supramaximal stimulation of the posterior tibial nerve and recorded from the thoracolumbar junctional space; thermal hyperalgesia assessed by measuring paw withdrawal latency (PWL); and sciatic function index (SFI). All the values of these parameters were obtained before the CCI procedure (day 1 as a preoperative baseline, and again on days 5, 12, 19, 26, 33, 47, 61, 75, and 89). SSEP was also measured 3 hr after the CCI operation. Data were also obtained from contralateral limbs., Results: All rats with CCI developed thermal hyperalgesia on day 5, as indicated by a significant reduction in PWL in the CCI limbs and a deterioration of the SFI compared with baseline values. These effects persisted to day 89. In the electrophysiologic study, 3 hrs after the CCI operation, the amplitude significantly decreased and latency significantly increased in all SSEP recordings. The changes persisted and showed no further statistically significant deterioration or recovery. The data demonstrated that the major electrophysiologic change after a constriction injury was the loss of conduction ability across the injury site in the fast-conducting fibers, but in the slow-conducting fibers the conduction ability was still preserved, which occurred immediately after the operation and persisted consistently for 89 days in the rats with behavior manifestations of neuropathic pain., Conclusions: Our findings suggest that SSEP is simple to obtain and sensitive in the acute phase of electrophysiological changes, but is limited for long-term evaluation after CCI.

Anesthesiologists are frequently consulted for performing lumbar cerebrospinal fluid (CSF) drainage to facilitate surgery or manage complications. Functional endoscopic sinus surgery (FESS) is a common treatment for chronic sinus diseases. Cerebrospinal fluid (CSF) leakage is a serious complication following FESS and is typically treated with an endonasal free or rotational mucoperichondrial flap. Continuous drainage of CSF with a lumbar subarachnoid catheter has been used in patients who have undergone neurosurgery but it is seldom used in the treatment of post-FESS CSF rhinorrhea. We present a 71-year-old male patient who suffered from CSF rhinorrhea after FESS, and was treated successfully with continuous lumbar CSF drainage. We are of the opinion that continuous CSF drainage with a lumbar subarachnoid catheter is an effective and safe modality of treatment for post-FESS CSF leakage.

Background: Accurate placement of the double-lumen endobronchial tube (DLETs) is essential for optimal gas exchange during one-lung ventilation. The present study was designed to estimate the insertion depth of left-sided DLET using a preoperative chest radiograph., Methods: Forty-five patients who underwent thoracic operations requiring intubation of a DLET were studied. The distance between the cephalic edge of the sixth cervical vertebra and the carina of the trachea (Dc-c) was measured from the anterior-posterior view of preoperative chest radiograph. After the tube was positioned in the main bronchus, a fiberoptic bronchoscope was introduced into the tracheal lumen to ensure the appropriate position of the DLET. Simple regression analysis for the insertion depth of the DLETs and Dc-c was performed., Results: There was a highly significant correlation between the insertion depth of the DLET and both the Dc-c (y = 0.5304x + 19.646) and the body height (y = 0.1022x + 10.525), with P < 0.001 and P < 0.01, respectively., Conclusions: To get the distance from the cephalic edge of the 6th cervical vertebra to the Dc-c from the chest radiograph preoperatively would be helpful for the evaluation of the proper insertion depth of the placement of DLET.