Thermal transport of confined water molecules in quasi-one-dimensional nanotubes.

Dimensions and molecular structures play pivotal roles in the principle of heat conduction. The dimensional characteristics of a solution within nanoscale systems depend on the degrees of confinement. However, the influence of such variations on heat transfer remains inadequately understood. Here, we perform quasi-one-dimensional non-equilibrium molecular dynamics simulations to calculate the thermal conductivity of water molecules confined in carbon nanotubes. The structure of water molecules is determined depending on the nanotube radius, forming a single-file, a single-layer, and a double-layer structure, corresponding to an increasing radius order. We reveal that the thermal conductivity of liquid water has a sublinear dependency on nanotube length exclusively when water molecules form a single file. A stronger confinement leads to behavioral and structural characteristics closely resembling a one-dimensional nature. Moreover, single-layer-structured water molecules exhibit enhanced thermal conductivity. We elucidate that this is due to the increase in the local water density and the absence of transitions to another layer, which typically occurs in systems with double-layer water structures within relatively large radius nanotubes.

Modeling of chemically active particles at an air-liquid interface.

The collective motion of chemically active particles at an air-liquid interface is studied theoretically as a dynamic self-organization problem. Based on a physical consideration, we propose a minimal model for self-propelled particles by combining hydrodynamic interaction, capillary interaction, driving force by Marangoni effect, and Marangoni flow. Our model has successfully captured the features of chemically active particles, that represent dynamic self-organized states such as crystalline, chain, liquid-like and spreading states.

[Clinical statistics of recurrent acute low-tone senseorineural hearing loss].

Recently, acute low-tone senseorineural hearing loss (ALHL) has become common, and its good prognosis is known well. On the other hand, several reports have suggested that ALHL is frequently associated with Meniere's disease. We retrospectively examined the clinical course of 357 cases that were diagnosed and treated as ALHL at our hospitals. Forty-four of these cases that showed high-tone hearing loss in association with age-related changes were classified as atypical cases. The clinical futures of 49 "poor prognosis cases", who experienced recurrent hearing loss and/or profound hearing loss, are reported. Eight of the 49 cases who experienced recurrences had progressive hearing loss upto middle or high tones. Seventeen cases complained of vertiginous sensation, and 8 of these cases experienced recurrent attacks of vertigo and were diagnosed as having Meniere's disease. The former seventeen cases accounted for 34.7% of the "poor prognosis cases", and the latter eight accounted for 16.3% of these cases. Our results suggest that the hearing loss is more frequently associated with Meniere's disease in cases who experience recurrent hearing loss. Thus, cases initially diagnosed as ALHL may include some cases of progressive hearing loss and Meniere's disease. Even in cases in which hearing improvement is obtained, careful clinical observation is necessary, especially in older patients with bilateral affliction and atypical presentation. ALHL has been generally considered to have a good prognosis, however our examination revealed a relatively high frequency of recurrences, progressive hearing loss and complication by vertigo. We recommend, based on this evidence, that careful explanation of this disease is necessary at time of initial informed consent.

Distribution of gentamicin in the guinea pig inner ear after local or systemic application.

Uptake and retention of gentamicin by cells in the guinea pig inner ear after a single peritoneal injection or local application on the round window were investigated using immunocytochemistry to localize the drug. The cells that accumulated the drug under the two conditions were the same, but staining for the drug was more intense and was often accompanied by widespread cochlear degeneration following local application. Soon after drug administration by either route, there was diffuse staining for the drug throughout all tissue within the labyrinth, including bone. At later times when distinct cell staining became evident, virtually all cell types were found to be positive, with several cell types staining more darkly for the drug than hair cells, indicating that hair cells were not the most avid in accumulating gentamicin. The infracuticular portion of auditory and vestibular hair cells as well as type III fibrocytes of the spiral ligament were positively stained in almost all cases and these sites were found to be positive for as long as six months post administration. In animals with loss of the organ of Corti, there was unusually intense staining for gentamicin in root cells of the spiral ligament, in marginal cells of the stria vascularis, and in cells of the spiral limbus. Dark staining of surviving cells in cases with overt tissue destruction suggests that variability in the extent of damage caused by the drug was determined more by the degree of its local uptake than by differences in animals' capacities to metabolize the drug systemically. The present results show that gentamicin may damage or destroy all cochlear cells following a single round window application. The findings broaden the scope of our knowledge of cochlear gentamicin uptake and damage and have implications for treatment of patients with vestibular disorders by infusion of aminoglycosides into the middle ear, as well as implications for prospects of rehabilitating patients that have been deafened by aminoglycosides.

Changes in cytochemistry of sensory and nonsensory cells in gentamicin-treated cochleas.

Effects of a single local dose of gentamicin upon sensory and nonsensory cells throughout the cochlea were assessed by changes in immunostaining patterns for a broad array of functionally important proteins. Cytochemical changes in hair cells, spiral ganglion cells, and cells of the stria vascularis, spiral ligament, and spiral limbus were found beginning 4 days post administration. The extent of changes in immunostaining varied with survival time and with cell type and was not always commensurate with the degree to which individual cell types accumulated gentamicin. Outer hair cells, types I and II fibrocytes of the spiral ligament, and fibrocytes in the spiral limbus showed marked decreases in immunostaining for a number of constituents. In contrast, inner hair cells, type III fibrocytes and root cells of the spiral ligament, cells of the stria vascularis, and interdental cells in the spiral limbus showed less dramatic decreases, and in some cases they showed increases in immunostaining. Results indicate that, in addition to damaging sensory cells, local application of gentamicin results in widespread and disparate disruptions of a variety of cochlear cell types. Only in the case of ganglion cells was it apparent that the changes in nonsensory cells were secondary to loss or damage of hair cells. These results indicate that malfunction of the ear following gentamicin treatment is widespread and far more complex than simple loss of sensory elements. The results have implications for efforts directed toward detecting, preventing, and treating toxic effects of aminoglycosides upon the inner ear.

Carbon dioxide laser vaporization of the inferior turbinate for allergic rhinitis: short-term results.

Carbon dioxide laser vaporization of the turbinate has recently become accepted as a common treatment for allergic rhinitis. Usually, only a single procedure is applied to minimize trauma. However, repeated procedures on separate days are often required to achieve an adequate effect. Therefore, we attempted a new method of vaporization and evaluated the outcome, and also tried to determine which patients have good indications for laser treatment. To widely and deeply vaporize the inferior turbinate, we repeated the procedure 3 times in 1 session after removing the carbon coating from the previous vaporization under nasal endoscopic observation. After the procedure, most patients experienced complete nasal obstruction for 2 or 3 days, but there was no intraoperative or postoperative bleeding or severe pain. All patients obtained improvement of their chief complaints and were satisfied 2 months after the operation. In particular, 60% of the patients were completely relieved of refractory nasal obstruction. Most patients were more satisfied with the effects than are those treated by the usual methods. Completely successful cases (improvement in all symptoms and complete satisfaction obtained) were selected and were compared with other cases. Favorable prognostic factors are more severe complaints, longer symptomatic periods, stronger allergic reactions, and worse nasal resistance and its greater improvement with administration of decongestant nasal drops. This method may be especially accepted by patients with severe complaints, in particular nasal obstruction, who do not experience enough relief with conservative therapies or have enough time to make frequent visits to an outpatient clinic over a period of several weeks.

Clinical study of acute low-tone sensorineural hearing loss: survey and analysis of glycerol test and orthostatic test.

Fifty patients (14 men and 36 women ranging in age from 16 to 66 years) with acute low-tone sensorineural hearing loss (ALHL) were retrospectively analyzed in this study. The glycerol test and the orthostatic test were performed. On the glycerol test, 43.8% of 16 ears of the 14 men and 33.3% of 39 ears of the 36 women with ALHL had a positive result. On the orthostatic test, 42.9% of the 14 men and 52.7% of the 36 women with ALHL had a positive result. In addition, 28.6% of the 14 men and 33.3% of the 36 women had hypotension with a systolic blood pressure of 100 mm Hg or less. Our results suggest that endolymphatic hydrops as shown by the glycerol test and an underlying autonomic imbalance and/or insufficient blood circulation as shown by the orthostatic test may be important factors in the causation of ALHL.

Malignant peripheral nerve sheath tumor of the parotid gland.

Malignant peripheral nerve sheath tumor (MPNST) has been defined as any malignant tumor arising from or differentiating toward cells of the peripheral nerve sheath. We treated a case of MPNST arising from the right parotid gland that showed a highly aggressive course. We reviewed the English-language literature published since 1990 and found 142 cases of head and neck MPNST reported within the past 13 years. The results of the review suggested that MPNSTs may arise from any organs of the head and neck. Immunohistochemical analysis of various neural markers plays a significant role in the evaluation of the histologic diagnosis. Curative treatment based on radical resection of MPNSTs of head and neck origin is more difficult than treatment of MPNSTs of other origins.

Head and neck metastases from occult abdominal primary site: a case report and literature review.

OBJECTIVES: A very rare case of cervical lymph node metastasis from the liver is reported. The clinical findings and the diagnosis of a metastasis to the head and neck from the isolated silent abdominal cancer are discussed. MATERIAL AND METHODS: The clinical and histopathological findings of a 56-year-old woman with a metastatic cervical lymph node of unknown origin are presented, together with a literature review of metastases from an occult abdominal primary. RESULTS: The primary site was identified as an undifferentiated cholangiolocellular carcinoma using immunostaining for anti-cytokeratin subclasses after autopsy. Fifty-two cases of head and neck metastases from an abdominal primary cancer were found and separately summarized according to the metastatic routes. CONCLUSIONS: When a metastatic neck cancer of unknown origin is diagnosed, it is very important to consider the possibility of a metastasis from an abdominal organ. Recognition of metastatic routes and their characteristics is helpful in the search for the occult abdominal primary site. Immunohistochemistry of the metastatic cancer may provide important information for identifying the primary site in cases of metastasis of an undifferentiated carcinoma.