Effects of dry-wet cycles on mechanical and leaching characteristics of magnesium phosphate cement-solidified Zn-contaminated soils.

Although magnesium phosphate cement (MPC) is conventionally deemed effective in heavy metal-contaminated soil remediation, the variations of its mechanical and leaching characteristics under the action of dry-wet cycles remain unclear as yet. This paper primarily addressed the effect of dry-wet cycles and fly ash on MPC-solidified zinc-contaminated soil via a disparate group of experiments. In this study, solidified cylindrical samples were subjected to different drying-wetting cycles ranging in times from 0 to 10 with varying content of fly ash. We then measured the mass loss, the unconfined compressive strength, and the Zn2+ leaching concentration of the leachate for the samples undergoing specified cycles. In addition, X-ray diffraction (XRD) and scanning electron microscopy (SEM) tests were conducted to explore the mechanism of MPC-solidified zinc-contaminated soil with fly ash. The results indicate that the Zn2+ concentration in the leaching solution increases rapidly with the number of cycles for 0-3 cycles and then tends to flatten out. Moreover, the unconfined compressive strength of the samples without fly ash decreases with an increasing dry-wet cycles. For the samples with various fly ash contents, in contrast, their unconfined compressive strength experiences an initial rise and a subsequent decline owing to the development of dry-wet cycles. With the purpose of facilitating practical applications, the appropriate fly ash content (approximately 20%) was estimated in terms of the enhanced dry-wet cycles durability of the solidified soil and unconfined compressive strength, according to the limited experimental measurements undertaken (for the Zn2+ concentration of 0.5). The role of dry-wet cycles in the physical and leaching properties of MPC-solidified soil may be of major practical significance.

[Endoscopic anatomy study of jugular foramen region].

OBJECTIVE: To observe anatomic structure of jugular foramen region by endoscope, to provide anatomic data for avoiding damnification in the surgery. METHOD: We performed the retrolabyrinthine and retrosigmoid endoscopic surgery on 8 fomalin-fixed adult cadaver specimens and observed the structures of jugular foramen by endoscope and compared the different surgeries at the same time. We excised the calvarium and cereburm and exposured and observed the nerves and vessels. Moreover we measured the the distance from internal accoustic pore to glossopharyngeal and analyse the data by SPSS. RESULT: All retrolabyrinthine endoscopic surgeries were performed successfully. Only 4 postsigmoid endoscopic surgeries were performed without damage of cerebellum which is the major obstacles. The distance from internal accoustic pore to glossopharyngeal was(8.26 ± 1.05) mm. About half of posterior inferior cerebellar arteries located to inboard of nerves. CONCLUSION: The jugular foramen region endoscopic surgery can be performed successfully by retrolabyrinthine. The "lockhole" technology by retrosigmoid is more difficult for blocking of cerebella. The internal acoustic porus is a fixed structure of the cerebellopontine angleand a perfect landmark to the surgery.

[Postlabyrinthine approach of cerebellopontine angle surgery via endoscope].

OBJECTIVE: To estimate the value of endoscope on postlabyrinthine approach of cerebellopontine angle surgery. METHOD: Transpostlabyrinthine endoscopic excision of glossopharyngeal nerve to treat 2 glossopharyngeal neuralgia patients. Observe the endoscopic eyespot and estimate the appliance and virtue of the surgery. RESULT: The two patients both have satisfied outcomes and remained free of disease after surgical treatment. We got a wide eyespot from trigeminal to vagus nerve. The internal acoustic porous is a fixed structure of the cerebellopontine angle and it is also a perfect landmark during the surgery. CONCLUSION: Endoscopic postlabyrinthine approach provides a shorter path to cerebellopontine angle and endoscope provides a unique way to explore the cerebellopontine angle and to identify the exact location of the pathological changes, including a multipoint of view. Complicated and skilled operation restricts the surgery.

[Clinical anatomy study of olfaction correlative nerves].

OBJECTIVE: To find out the relation of the olfactory nerves, the optic nerve, and the nasal sinuses. Provide anatomic data for not to damnify olfactory nerves in the surgery. METHOD: To measure the olfactory nerves, the olfactory bulb, and olfactory tract on 16 adult cadaveric specimens, and observe the relation of the olfactory nerves, the optic nerve,and the nasal sinuses. RESULT: Length of the olfactory tract was (29.32 +/- 2.11) mm, width of the olfactory tract was (3.36 +/- 0.83) mm. The distance from the midpoint of the olfactory tract to the midline of the skull was (5.48 +/- 1.02) mm. The angle between olfactory tract and midline of the skull was (21.32 +/- 3.28) degrees. Length of the olfactory bulb was (10.43 +/- 2.35) mm, width of the olfactory bulb was (5.12 +/- 0.62) mm. 27/32 olfactory tracts were border upon with sphenoid sinus and ethmoid sinus, 3/32 olfactory tracts were border upon with ethmoid sinus, 2/32 olfactory tracts were border upon with frontal sinus. All olfactory tracts crossed the optic nerve at the internal meatus of optic nerve canal. The olfactory bulb and ethmoid bulb were on equal line. CONCLUSION: Almost all olfactory tracts were lied in the inboard of the orbital cavity, protect the roof of the nasal sinus to avoid damnify the olfactory nerves. It is easy to pull out the olfactory nerves when raising the cerebra in the operation of anterior cranial fossae.