Freeze-drying synthesis of an amorphous Zn(2+) complex and its transformation to a 2-D coordination framework in the solid state.

An amorphous and metastable precursor for a Zn two-dimensional coordination framework was synthesised via freeze drying. The precursor comprises randomly packed discrete clusters of a Zn complex. The amorphous-to-crystalline framework transformation, which was triggered by the gentle application of heat or pressure, was accompanied by a change in the coordination geometry of the Zn(2+) ions from tetrahedral to octahedral symmetry.

Glass formation via structural fragmentation of a 2D coordination network.

The structure of a glass obtained by the melt quenching of a two-dimensional (2D) coordination network was examined. X-ray analyses disclosed a 2D-to-0D structural transformation before and after glass formation. The mechanism is unique to coordination compounds, as it is characterized by labile and flexible coordination bonds.

Synthesis of magnesium ZIF-8 from Mg(BH4)2.

Porous Mg(2-methyl imidazolate)2 (Mg-ZIF-8) was synthesised from Mg(BH4)2 as a precursor under an Ar atmosphere. It possesses an uncommon tetrahedral Mg(2+)-N coordination geometry that is stabilised by the formation of a framework, and it exhibits a Brunauer-Emmett-Teller surface area greater than 1800 m(2) g(-1).

Erdheim-Chester disease associated with intramedullary spinal cord lesion.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis. We present a case of a 56-year-old male with ECD. As time progressed, involvement of the orbital fossa, cranial convexity, spinal cord, brain stem, thyroid, lung, retroperitoneum, lower extremity bones and skin were found. Previously reported cases reveal the frequency of ECD with spinal cord involvement is rare. Although this was a presumed diagnosis based on other lesions, our case is the first in which both intramedullary and epidural masses are present.

Environmental mobility of cobalt-Influence of solid phase characteristics and groundwater chemistry.

The adsorption of cobalt on samples from a potential waste repository site in an arid region was investigated in batch experiments, as a function of various solution phase parameters including the pH and ionic strength. The samples were characterized using a range of techniques, including BET surface area measurements, total clay content and quantitative X-ray diffraction. The statistical relationships between the measured cobalt distribution coefficients (K(d) values) and the solid and liquid phase characteristics were assessed. The sorption of cobalt increased with the pH of the aqueous phase. In experiments with a fixed pH value, the measured K(d) values were strongly correlated to the BET surface area, but not to the amount of individual clay minerals (illite, kaolinite or smectite). A further set of sorption experiments was undertaken with two samples of distinctive mineralogy and surface area, and consequently different sorption properties. A simple surface complexation model (SCM) that conceptualized the surface sites as having equivalent sorption properties to amorphous Fe-oxide was moderately successful in explaining the pH dependence of the sorption data on these samples. Two different methods of quantifying the input parameters for the SCM were assessed. While a full SCM for cobalt sorption on these complex environmental substrates is not yet possible, the basic applicability and predictive capability of this type of modeling is demonstrated. A principal requirement to further develop the modeling approach is adequate models for cobalt sorption on component mineral phases of complex environmental sorbents.

Stenting for Left Subclavian Artery Stenosis before and after Coronary Artery Bypass Grafting Using the Internal Mammary Artery: A Report of Three Cases.

SUMMARY: Stenosis of the subclavian artery proximal to the origin of the internal mammary artery (IMA) used for coronary artery bypass grafting may produce flow reversal (steal syndrome) and cause myocardial ischemia. We present three cases of subclavian artery stenosis proximal to the IMA before and after CABG. The first case developed symptomatic myocardial ischemia resulting from a variant of coronary-subclavian steal syndrome. The second case had asymptomatic subclavian artery stenosis proximal to the IMA used for CABG. In the third case we planned to perform CABG using the left IMA to treat cardiac ischemia. All of the patients were successfully treated by stent placement without the use of a protection device. In the first and second cases, cardiac ischemia did not appear during balloon inflation of the subclavian artery and no embolic complication occurred. In the third case, CABG was performed six months after stenting. Subclavian artery stenting is a valid alternative to surgical treatment to restore the flow to the IMA before or after CABG.

A minimally invasive endoscopic transsphenoidal approach with an endonasal septal pushover technique by using a modified nasal speculum.

Whereas the endoscopic endonasal transsphenoidal approach has been applied in patients with pituitary lesions as a potentially efficacious and less invasive surgical technique, the sinonasal step of a series of the surgical procedures is generally not well known to neurosurgeons. This is one of the reasons why the endoscopic technique has not been fully been adopted as a routine surgical procedure approaching towards the sella. The present paper describes the technical details of a purely endoscopic approach using an endonasal septal pushover technique. We also present a newly designed nasal speculum specialized for this endoscopic endonasal technique. As compared to the endoscopic endonasal approach previously reported, the surgical procedure required for sphenoidotomy with the aid of the modified speculum was simplified and thereby less time-consuming. This technique has been performed in 40 patients with several types of pituitary lesions. All patients recovered rapidly without significant rhinological complications. Despite a limited number of cases, our experience suggests that this simplified endoscopic technique could encourage a more routine use of endoscopes in the endonasal approach for pituitary lesions.

Traumatic bilateral common carotid artery dissection due to strangulation. A case report.

SUMMARY: We report a case of bilateral common carotid artery dissection due to strangulation successfully treated by stent placement, with a review of the literature. A 61-year-old woman was strangled by an apron strap. She was admitted to our hospital with tetraparesis, because of spinal cord injury. On the next day, her left hemiparesis aggravated and left facial palsy newly appeared. Diffusion weighted magnetic resonance imaging (MRI) showed new ischemic lesions in the right cerebral hemisphere. Aortography revealed bilateral common carotid artery dissection. Moreover, thrombus or intimal flap was recognized in the right common carotid artery. The right common carotid dissection was fixed with deployment of self expanding stents to prevent the aggravation of ischemic stroke at that time. The contralateral lesion was also treated ten days later because small ischemic lesions were newly recognized in the left hemisphere on MRI. No new neurological deficit appeared after bilateral carotid artery stenting. Her paraparesis completely improved two months after the spinal cord injury. Carotid artery stenting using self expanding stents was especially effective as the treatment for bilateral carotid artery dissection.

Coil embolization training using a rabbit saccular aneurysm model.

SUMMARY: We developed a rabbit saccular aneurysm model for coil embolization training. Elastaseinduced aneurysms were created successfully in about 80% of the rabbits. The aneurysms were usually broad in the neck and lengthy. At the 28(th) postoperative day, the aneurysms were about 1.5 times larger in both width and height than they had been at the 14(th) day. All aneurysms were successfully embolized with 18-sized electrically detachable (ED) platinum coils. After embolization, almost all aneurysms had a neck remnant. In conclusion, this model is useful not only for learning the technique of coil embolization but also for testing new embolic materials. The rabbit aneurysm model proved to be an efficacious training modality for endovascular coil embolization.

Endovascular coil embolization for cerebral aneurysms solely using ultrasoft coils.

SUMMARY: We report a series of coil embolizations for small aneurysms solely using GDC ultrasoft coils and discuss the advantages of this method. Seven small aneurysms (< 4.0 mm) were embolized solely with ultrasoft coils. Ultrasoft coils were sequentially inserted into aneurysms. Immediately after embolization, five aneurysms were completely occluded, and two exhibited body filling. All cases were treated successfully without any complications. In conclusion, ultrasoft coils were found efficacious for the treatment of small, irregular-shaped, and ruptured aneurysms; their softness and malleability facilitated their compaction into an aneurysm.

Endovascular treatment of unruptured cerebral aneurysms.

76 consecutive patients with 78 unruptured cerebral aneurysms underwent endovascular therapy from July 1999 to May 2004 in our institute. For the wide-necked aneurysms, the remodeling technique, double microcatheter technique, or stent-assisted coil embolization was used, while a parent artery occlusion or covered stent was applied for the giant or fusiform aneurysms. Immediate angiographical results demonstrated 33 complete occlusions, 26 neck remnants, and 14 dome fillings. Four cases were treated with parent occlusion or stenting only, and one case was not treated with embolization but with clipping due to the rupture of the aneurysm during coil embolization. Immediate angiographic findings demonstrated that in aneurysms between 5 to 10 mm, the rate of complete occlusion was 48%, that of neck remnants 33%, and that of dome fillings 27%. In aneurysms between 11 to 25 mm, the rate of complete occlusion was 14%, that of neck remnants 28%, and that of dome fillings was 58%. In the angiographic follow-up results, all aneurysms smaller than 5 mm showed complete occlusion. In aneurysms between 5 to 10 mm, 74% of the aneurysms showed complete occlusion, and 21% showed neck remnants, and 5% showed dome filling. In aneurysms between 10 to 24 mm, 25% showed complete occlusion, while 75% showed dome filling. The overall mortality rate was 0% and the morbidity rate was 3.7% (2 major strokes, 1 minor stroke) at 30-days after embolization. In the clinical follow-up study, one case of a large basilar tip aneurysm caused a fatal rupture 28 months after the initial embolization. Endovascular therapy was performed on the unruptured aneurysms and was found to be an acceptable treatment, except for durability in cases of large aneurysms.

Radionuclide applications in laboratory studies of environmental surface reactions.

The advantages of using radionuclides for laboratory studies of environmental processes include the wide range of element concentrations that can be studied, the capability to simultaneously study several isotopes in a single experiment, the direct applicability to the behaviour of radioactive waste or fallout, and the ability to study the mechanisms, reversibility and kinetics of environmental reactions under controlled conditions. These attributes are demonstrated using specific examples drawn from case studies in Australia, including radionuclide fallout onto tropical soils, the association of trace metals with harbour sediments and the behaviour of uranium in natural and contaminated systems.

Soil-water distribution coefficients and plant transfer factors for (134)Cs, (85)Sr and (65)Zn under field conditions in tropical Australia.

Measurements of soil-to-plant transfer of (134)Cs, (85)Sr and (65)Zn from two tropical red earth soils ('Blain' and 'Tippera') to sorghum and mung crops have been undertaken in the north of Australia. The aim of the study was to identify factors that control bioaccumulation of these radionuclides in tropical regions, for which few previous data are available. Batch sorption experiments were conducted to determine the distribution coefficient (K(d)) of the selected radionuclides at pH values similar to natural pH values, which ranged from about 5.5 to 6.7. In addition, K(d) values were obtained at one pH unit above and below the soil-water equilibrium pH values to determine the effect of pH. The adsorption of Cs showed no pH dependence, but the K(d) values for the Tippera soils (2300-4100 ml/g) exceeded those for the Blain soils (800-1200 ml/g) at equilibrium pH. This was related to the greater clay content of the Tippera soil. Both Sr and Zn were more strongly adsorbed at higher pH values, but the K(d) values showed less dependence on the soil type. Strontium K(d)s were 30-60 ml/g whilst Zn ranged from 160 to 1630 ml/g for the two soils at equilibrium pH. With the possible exception of Sr, there was no evidence for downward movement of radionuclides through the soils during the course of the growing season. There was some evidence of surface movement of labelled soil particles. Soil-to-plant transfer factors varied slightly between the soils. The average results for sorghum were 0.1-0.3 g/g for Cs, 0.4-0.8 g/g for Sr and 18-26 g/g for Zn (dry weight) with the initial values relating to Blain and the following values to Tippera. Similar values were observed for the mung bean samples. The transfer factors for Cs and Sr were not substantially different from the typical values observed in temperate studies. However, Zn transfer factors for plants grown on both these tropical soils were greater than for soils in temperate climates (by more than an order of magnitude). This may be related to trace nutrient deficiency and/or the growth of fungal populations in these soils. The results indicate that transfer factors depend on climatic region together with soil type and chemistry and underline the value of specific bioaccumulation data for radionuclides in tropical soils.

Clinical results of percutaneous transluminal angioplasty and stenting for intracranial vertebrobasilar atherosclerotic stenoses and occlusions.

SUMMARY: Eighteen patients with intracranial vertebrobasilar stenosis and occlusion were treated by PTA or stenting. In 11 of 18 cases, only PTA was performed and in seven of 18 cases, we used stents. The mean stenosis before and after PTA/stenting was 82.8% and 22.3%, respectively. In 11 cases of PTA only, the stenotic rate decreased from 81.8% to 29.6%, while 85.0% of the stenotic rate remarkably reduced to 6.0% in seven cases of stenting. The 30 days morbidity and 30 days mortality rate were 5.5% and 5.5%, respectively. There was only one haemorrhagic complication (cerebellar haemorrhage) in cases of stenting, and no ischemic events during or after the procedures. Restenosis (more than 50% stenosis) occurred in four of 18 cases(22.2%) during mean followup period of 12 months. Two patients with VA occlusion before treatment, developed restenosis and reocclusion. Complete total occlusion seems to be a high-risk lesion and strict follow-up is required. In this study, PTA/stenting for intracranial vertebrobasilar artery stenosis or occlusion is an effective treatment, but strict indications may be required because procedure-related 30 days morbidity rate was 5.5% in addition to unclear natural history.

Technique and Clinical Results of Carotid Stenting under Distal Protection.

SUMMARY: We perfomed carotid artery stenting(CAS) in 215 patients from August 1997 to October 2003 mainly using the distal protection technique. Our technique and clinical results are described in this paper.

The study on the patency of the perforating arteries after stent placement in atherosclerosis induced rabbits.

SUMMARY: The number of successful case reports with percutaneous transluminal angioplasty (PTA) / stenting for intracranial atherosclerotic stenoses is recently increasing with the advent of flexible coronary stents. However, it is not well known whether the perforating artery is occluded or not after stent placement in the atherosclerotic stenotic vessels. We investigated this issue using five New Zealand white rabbits. We deployed stainless steel stents in the atherosclerosis-induced abdominal aorta across the lumbar artery in which the diameters of the abdominal arteries were similar to those of human intracranial arteries. We evaluated the patency of lumbar artery by angiography and scanning electron microscopy three months after stent placement. The lumbar arteries were patent in four out of five rabbits. However, SEM findings demonstrated stent struts were covered with thick neointima and the ostia between stent struts were partially occluded. It is possible that stent placement in the atherosclerotic arteries can cause the obliteration of the perforating arteries.

Analysis of Complications related to Endovascular Therapy for Dural Arteriovenous Fistulae.

SUMMARY: In this paper, we reviewed our cases of dural arteriovenous fistulae (dural AVFs) and analyzed periprocedural complications. In 157 procedures, we encountered 14 complications. Overall, complication rate of 9% was seen.We divided these complications into five subgroups such as cranial nerve palsy, coil-related trouble, thromboembolic complication, vessel perforation, and radiation-related trouble. There were five transient abducent nerve palsies in cases with cavernous sinus dural AVFs. There were two cases of coil unraveling and two cases of coil migration. In two cases, direct puncture of the internal jugular vein was performed to retrieve the unraveled coil by using dual microcatheter and guidewire snare technique. We encountered two thromboembolic complications. In one case, venous infarction was recognized after polyvinyl alcohol particle embolization. In two cases of vessel perforations, there were no new neurological deficits except one case with transient Gerstmann syndrome. In endovascular treatment of dural AVF, serious complications are rare and can be prevented if maximum attention is paid during the procedure.

Standard Technique of PTA/stenting for Atherosclerotic Intracranial Arterial Stenosis.

SUMMARY: PTA/stenting for the intracranial arteriosclerotic lesion is effective and novel treatment. Our standard technique to avoid serious complications, such as vessel rupture or acute occlusion was introduced in this paper.

Doppler flow and arterial location in ovarian tumors.

OBJECTIVES: This prospective study investigated the clinical evaluation of transvaginal color Doppler ultrasonography in the diagnosis of ovarian tumors. METHODS: Transvaginal ultrasonography (morphological assessment, DePriest's index) and color Doppler analysis were performed for 31 malignant and 64 benign tumors ovarian tumors. Serum tumor markers such as CA125, CA72-4, and STN were measured. RESULTS: Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were as follows: DePriest's index, 90.3%, 73.4%, 62.2%, 94.0%, 78.9%; CA125, 70.4%, 87.7%, 73.1%, 86.2%, 82.1%; minimum pulsatile index combined with detection of location of arterial blood flow, 83.9%, 98.4%, 96.3%, 92.6%, 93.7%, respectively. In cases where arterial blood flow was recognized, malignant tumors had significantly fewer diastolic notches, while benign tumors had many diastolic notches. The difference in the presence of diastolic notch between malignant and benign tumors was significant (P<0.0004). CONCLUSIONS: For diagnosis of ovarian tumors, transvaginal color Doppler analysis combined with detection of arterial location is more useful than other procedures.

The diffusion and sorption of volatile organic compounds through kaolinitic clayey soils.

Laboratory experiments to estimate the effective molecular diffusion coefficient (D(e)) and sorption coefficient (K(d)) for volatile organic compounds through natural clayey soils were conducted using diffusion testing apparatus. The compounds tested were methyl ethyl ketone (MEK), toluene and trichloroethylene (TCE). The D(e) and K(d) values were determined by a curve fitting procedure. The compound losses, and the effects of porous disks used in the apparatus were significant. The transport of MEK was faster than that of TCE and toluene because of the lower sorption to the soils. The D(e) values of all the compounds were of the order of 10(-10) m(2)/s and smaller than the diffusion coefficient in pure aqueous solution at infinite dilution (D(0)), due to the tortuosity of the samples. The effects of the sample thickness on the parameter determination were not significant. Comparison to the K(d) values estimated from batch sorption tests and from organic carbon content (f(oc))-based predictions showed that the diffusion test results were intermediate between those from the other two methods. The diffusion tests use compacted soil samples and should be more relevant to in situ conditions, but the reliability of the tests is affected by large compound losses that cause uncertainties in their interpretation. It is recommended that more than one method be used to assess K(d) values.