A dynamic one-dimensional model for simulating unsteady air-water stratified flow in sewer pipes.

Ventilation is paramount in sanitary and stormwater sewer systems to mitigate odor problems and avert pressure surges. Existing numerical models have constraints in practical applications in actual sewer systems due to insufficient airflow modeling or suitability only for steady-state conditions. This research endeavors to formulate a mathematical model capable of accurately simulating various operational conditions of sewer systems under the natural ventilation condition. The dynamic water flow is modeled using a shock-capturing MacCormack scheme. The dynamic airflow model amalgamates energy and momentum equations, circumventing laborious pressure iteration computations. This model utilizes friction coefficients at interfaces to enhance the description of the momentum exchange in the airflow and provide a logical explanation for air pressure. A systematic analysis indicates that this model can be easily adapted to include complex boundary conditions, facilitating its use for modeling airflow in real sewer networks. Furthermore, this research uncovers a direct correlation between the air-to-water flow rate ratio and the filling ratio under natural ventilation conditions, and an empirical formula encapsulating this relationship is derived. This finding offers insights for practical engineering applications.

Numerical study on hydraulic characteristics of rotating stepped dropshafts in deep urban tunnels.

As an important component of the deep tunnel drainage system for dealing with urban waterlogging, the rotating stepped dropshaft has been proposed due to its small air entrainment. However, the hydraulic characteristics inside the shaft still need to be fully studied. In this study, the flow patterns, water velocity, and pressure in the rotating stepped dropshaft under different flow rates and geometric parameters were studied using a three-dimensional numerical model. The results show that increasing the central angle of the step and reducing the step height can both reduce the terminal velocity. A theoretical formula for predicting the terminal velocity was established and well validated. The connection between the shaft and the outlet pipe poses a severe threat to the structural safety due to alternating positive and negative pressures. Wall-attached swirling flow generates a circular high-pressure zone at the bottom of the dropshaft and the larger the flow rate, the greater the pressure gradient at the center of the bottom. By using the momentum theorem and considering the impact pressure range of the swirling flow, the shaft bottom pressure can be predicted reasonably well.

Key Role Effect of Samarium in Realizing Zero Thermal Quenching and Achieving a Moisture-Resistant Reddish-Orange Emission in Ba3LaNb3O12:Sm3.

The strategy to enhance phosphor stability against thermal quenching and moisture conditions will contribute to controlling the feature of phosphor-converted white-light-emitting diodes (pc-WLEDs). Herein, an effective strategy is achieved with the incorporation of Sm3+ ions, and a robust reddish-orange emission (no thermal quenching up to 498 K) is obtained based on Ba3LaNb3O12 as a host. In light of excitation by near-ultraviolet irradiation at 408 nm, Ba3LaNb3O12:Sm3+ gives rise to a typical signal ascribed to the 4G5/2 → 6HJ/2 (J = 5, 7, 9, and 11) transitions of Sm3+ ions. The concentration quenching effect is observed when the Sm3+ content exceeds 10%, and the quenching mechanism is caused by electronic dipole-dipole interactions. Based on the narrow emission curves, a very high color purity (92.4%) could be recorded. The Sm3+ substitution at the Ba2+/La3+ site leads to a rigid structural lattice and abundant electron-trapping centers for the Sm3+ ions, which will be responsible for the zero-thermal-quenching phenomenon. In addition, oleic acid (OA) is selected to form a hydrophobic covering surface structure to protect Ba3LaNb3O12:Sm3+, which can assist in improving the moisture resistance. The most favorable parameters concerning the warm-light emission (a high general color rendering index, Ra, of 85.7 and a low correlated color temperature, CCT, of 4965 K) can be achieved in pc-WLEDs containing an OA-modified sample. Moreover, its luminous efficiency, LE, can maintain 82.9% of its initial value after 120 h under controlled environmental conditions of 85 °C and 85% humidity. These results pave a new way to optimize the sample as a potential candidate for red-emitting materials.

Investigation on water and air characteristics in Helicoidal Ramp Dropshafts.

Plunge dropshafts are widely used in urban drainage systems, but they can carry large amounts of air into the system, endangering the safety of the system. In this paper, a 3D numerical model is established to investigate the water flow configuration and air characteristics in a helicoidal ramp dropshaft. The simulations under different outlet pressures and water flow rates were simulated, and the results show that the air demand decreases with the increase of outlet pressure, especially in the case of low water flow. In the case of higher outlet pressure, the air demand first increases then decreases with the increase of the water flow rate. The dragging force of water has little effect on the pressure gradient in the dropshaft. The increase of ramp turns leads to the increase of terminal velocity at the same flow rate, and the air demand first increases and then decreases with the increase of ramp turns.

Realization of an Optical Thermometer via Structural Confinement and Energy Transfer.

The influence of temperature on a variety of physiological or chemical processes has generated considerable interest, and recently noninvasive lanthanide-incorporated optical thermometers have been considered as promising candidates for monitoring its changes at different scales. Herein, a novel Bi3+-activated Sr3-xGdxGaO4+xF1-x phosphor with tunable color has been constructed by a cooperative cation-anion substitution strategy with to the replacement of [Sr2+-F-] by [Gd3+-O2-]. When x = 0, the sample Sr3GaO4F/Bi3+ possesses a peak wavelength at 438 nm, and this value will shift to 470 nm if x is equal to 1 (Sr2GdGaO5/Bi3+). In addition, photoluminescence tuning from blue to red has been realized successfully by an efficient Bi3+ → Eu3+ energy migration model in Sr2.6Gd0.4GaO4.4F0.6 samples. The specific Bi3+ → Eu3+ energy transfer has been explained by dipole-dipole interactions derived from a model of the Dexter pathway. Intriguingly, the two dopants (a blue signal from Bi3+ and a red signal from Eu3+) possess different thermal responses to increasing temperature. Accordingly, the intensity ratio values are sensitive to the temperature changes. The energy level cross relaxation causes the quenching effect of Bi3+, and the multi-phonon de-excitation mode leads to the thermal quenching of Eu3+. At room temperature (298 K), the determined maximum relative sensitivity (Sr) is 1.27% K-1. Moreover, the absolute sensitivity (Sa) is 0.067 K-1 since the temperature is elevated to 523 K. The collected results are superior to most of the reported optical thermometry materials.

Numerical study on dynamic behavior of entrapped air in a partially filled pipe.

Rapid filling in horizontal partially filled pipes with entrapped air may result in extreme pressure transients. This study advanced the current understanding of dynamic behavior of entrapped air above tailwater (the initial water column with a free surface in a partially filled pipe) through rigid-column modeling and sensitivity analysis of system parameters. Water and air were considered as incompressible fluid and ideal gas, respectively, and the continuity and momentum equations for water and a thermodynamic equation for air were solved by using the fourth order Runge-Kutta method. The effects of system parameters were examined in detail, including tailwater depth, entrapped air volume, driving head, pipe friction, and relative length of entrapped air and pipe. The results indicate that the presence of tailwater can mitigate the peak pressure when with identical initial volumes of entrapped air, as it can be considered to reflect a certain amount of loss of the net driving head. However, the peak pressure can increase as much as about 45% for the cases with fixed pipe length, due to the reduction in the initial entrapped air volume. The rise time for the first peak pressure was closely related to pipe friction, whereas the oscillation period (defined as the time duration between the first and second peaks) was virtually irrelevant. The applicability of the rigid-column model was discussed, and a time scale relevant indicator was proposed. When the indicator is larger than 20, the relative difference between the peak pressure estimation and experimental measurements is generally below 5%.

Numerical study on effects of chamber design and multi-inlet on storm geyser.

Storm geysers increasingly occur in sewer systems under climate change and rapid urbanization. Mitigation measures are in great demand to avoid safety problems. In this study, three-dimensional computational fluid dynamics models of single-inlet and multi-inlet systems were established to investigate geysering induced by rapid filling and assess the effectiveness of potential mitigation methods. The modeling results suggest that increasing the capacity of the downstream pipe before the inflow front reaches the chamber can effectively reduce the maximum geyser pressure. The peak pressure can be significantly mitigated when the chamber size is designed with care and the drop height between the upstream and downstream pipes is reduced. A diversion deflector with air vents and an orifice plate at the riser top end can alleviate the maximum pressure by about 65% with about 75% of the entrapped air being released. The peak pressure during the geyser event in the multi-inlet model is less than that of a single-inlet model under the same total inflow condition, but more water can be released.

[Endovascular reconstructive treatment of vertebrobasilar fusiform aneurysms by multiple overlapping stents with or without coils].

OBJECTIVE: To explore the feasibility, safety and efficacy of endovascular reconstructive treatment by multiple overlapping stents with or without coils. METHODS: Totally 17 patients of vertebrobasilar fusiform aneurysms treated by multiple overlapping stents with or without coils between September 2011 and September 2015 in Department of Neurosurgery, Beijing Hospital were retrospectively reviewed. There were 15 male and 2 female patients with mean age of (47±13) years. Clinical manifestations included subarachnoid hemorrhage in 5 patients, cerebral ischemia or infarction in the posterior circulation in 5 patients, mass effect accompanied with brainstem infarction in 1 patients, headache or dizziness in 4, and incidental findings in 2 patients. Aneurysm located in intracranial vertebral artery in 11 patients, vertebrobasilar junction in 2 patients, and basilar trunk in 4 patients. Mean aneurysmal size was 18.5 mm×8.0 mm(length×width). RESULTS: Sole stenting with overlapping stents was performed in 8 patients, and overlapping stents with coils was applied in 9 patients. Post-procedural hemorrhage occurred in a patient with a giant basilar trunk fusiform aneurysm and led to death. The 16 surviving patients were clinically followed up for a mean of 21.1 months. One patient had a modified Rankin score of 4, and the other patients had a good recovery. Among 15 patients with a mean angiographic follow-up of 8.6 months, 9 patients had their aneurysms further thrombosed, 3 patients were stable, and 3 patients with a recurred aneurysm. Final complete occlusion was achieved in 7 patients. CONCLUSION: Reconstructive treatment by overlapping stents with or without coils is feasible and relative safe in vertebrobasilar fusiform aneurysms.

Synthesis and biological evaluation of 1,3-diaryl pyrazole derivatives as potential antibacterial and anti-inflammatory agents.

Three series of 1,3-diaryl pyrazole derivatives bearing aminoguanidine or furan-2-carbohydrazide moieties have been synthesized, characterized and evaluated for antibacterial and anti-inflammatory activities. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains (including multidrug-resistant clinical isolates) and Gram-negative bacterial strains with minimum inhibitory concentration values in the range of 1-64 µg/mL. Compounds 6g, 6l and 7l presented the most potent inhibitory activity against Gram-positive bacteria (e.g. Staphylococcus aureus 4220), Gram-negative bacteria (e.g. Escherichia coli 1924) and the fungus, Candida albicans 7535, with minimum inhibitory concentration values of 1 or 2 µg/mL. Compared with previous studies, these compounds exhibited a broad spectrum of inhibitory activity. Furthermore, compound 7l showed the greatest anti-inflammatory activity (93.59% inhibition, 30 min after intraperitoneal administration), which was more potent than the reference drugs ibuprofen and indomethacin.

Synthesis and antimicrobial evaluation of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety.

Three series of 5-aryl-1,2,4-triazole-3-thione derivatives containing a rhodanine moiety (5a-k, 6a-i, and 7a-i) have been synthesized, characterized and evaluated for their antibacterial activity. Some of these displayed potent antibacterial activity against several Gram-positive and Gram-negative bacterial strains (including multidrug-resistant clinical isolates) with minimum inhibitory concentration (MIC) values in the range of 4-64 µg/mL and minimum bactericidal concentration (MBC) values in the range of 8-256 µg/mL. Compared with previously reported rhodanine derivatives, these compounds exhibited a broad spectrum of antibacterial activity by means of introducing 4-amino-5-aryl-1,2,4-triazole-3-thione moiety. Notably, compound 5f exhibited good antibacterial activity against Staphylococcus aureus RN 4220, S. aureus 209, S. aureus 503, Gram-negative bacteria (Escherichia coli 1924), and Candida albicans 7535 with MBC values of 8 or 16 µg/ml. All of the compounds synthesized in the current Letter were characterized by (1)H NMR, (13)C NMR, infrared and mass spectroscopy.

[Short-term outcome of single stenting technique for unruptured wide-necked tiny aneurysms of the anterior circulation].

OBJECTIVE: To evaluate the short-term outcome of single stenting technique for unruptured, wide-necked, tiny aneurysms of the anterior circulation. METHODS: Eleven unruptured, wide-necked, tiny aneurysms of the anterior circulation were treated by a single stent deployed in the parent artery between January 2008 and July 2013 in Department of Neurosurgery in Beijing Hospital. The maximum diameter of the aneurysms ranged from 2.0 to 3.0 mm, mean (2.4 ± 0.4) mm, and the dome-to-neck ratios were all ≤ 1.2. The locations were clinoid segment of internal carotid artery (n=2), posterior communicating artery origin (n=4), anterior choroidal artery origin (n=2) and middle cerebral artery bifurcation (n=3). All internal carotid aneurysms were located in the medial and/or ventral wall of the internal carotid artery. The rate of aneurysm obliteration and rupture during follow-up was obtained by repeat angiography and clinic or telephone interview respectively. RESULTS: Sole stent placement in the parent artery was intentionally performed for nine aneurysms, while attempt of coiling after stent deployment for the other two aneurysms failed due to unsuccessful microcatherization. Ten stents were successfully deployed, of which one was used to treat two tandem lesions simultaneously. Only one aneurysm became smaller immediately postprocedure. No perioperative complications occurred. Angiographic follow-up after a mean period of (13 ± 6) months (range 8-24 months) revealed that 8 aneurysms did no change in size, 2 became smaller and only one was totally occluded. Asymptomatic in-stent stenosis of the parent artery was found in all 3 shrinking or occluded aneurysms. No aneurysm rupture was observed in the clinical follow-up. CONCLUSION: For those unruptured, wide-necked, tiny aneurysms arising at branching sites in the anterior circulation, single stenting technique seems to be a safe alternative treatment, while the short-term rate of aneurysm occlusion is low.

Synthesis and positive inotropic evaluation of [1,2,4]triazolo[3,4-a]phthalazine and tetrazolo[5,1-a]phthalazine derivatives bearing substituted piperazine moieties.

Four series of [1,2,4]triazolo[3,4-a]phthalazine and tetrazolo[5,1-a]phthalazine derivatives bearing substituted piperazine moieties were synthesized and evaluated for their positive inotropic activity by measuring the left atrium stroke volume in isolated rabbit-heart preparations. Several compounds were developed and showed favorable activities compared to the standard drug milrinone, with (4-([1,2,4]triazolo[3,4-a]phthalazin-6-yl)piperazin-1-yl)(p-tolyl)methanone (5g) being identified as the most potent with an increased stroke volume of 19.15±0.22% (milrinone: 2.46±0.07%) at a concentration of 3×10(-5) M. A preliminary study of mechanism of action revealed that 5g displayed its positive inotropic effect may be related to the PDE-cAMP-PKA signaling pathway. Compounds exhibiting inotropic effects were also evaluated in terms of the chronotropic effects.

Practical Nomograms and Risk Stratification System for Predicting the Overall and Cancer-specific Survival in Patients with Anaplastic Astrocytoma.

OBJECTIVE: Anaplastic astrocytoma (AA) is an uncommon primary brain tumor with highly variable clinical outcomes. Our study aimed to develop practical tools for clinical decision-making in a population-based cohort study. METHODS: Data from 2997 patients diagnosed with AA between 2004 and 2015 were retrospectively extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The LASSO and multivariate Cox regression analyses were applied to select factors and establish prognostic nomograms. The discriminatory ability of these nomogram models was evaluated using the concordance index (C-index) and receiver operating characteristic curve (ROC). Risk stratifications were established based on the nomograms. RESULTS: Selected 2997 AA patients were distributed into the training cohort (70%, 2097) and the validation cohort (30%, 900). Age, household income, tumor site, extension, surgery, radiotherapy, and chemotherapy were identified as independent prognostic factors for both overall survival (OS) and cancer-specific survival (CSS). In the training cohort, our nomograms for OS and CSS exhibited good predictive accuracy with C-index values of 0.752 (95% CI: 0.741-0.764) and 0.753 (95% CI: 0.741-0.765), respectively. Calibration and DCA curves showed that the nomograms demonstrated considerable consistency and satisfactory clinical utilities. With the establishment of nomograms, we stratified AA patients into high- and low-risk groups, and constructed risk stratification systems for OS and CSS. CONCLUSIONS: We constructed two predictive nomograms and risk classification systems to effectively predict the OS and CSS rates in AA patients. These models were internally validated with considerable accuracy and reliability and might be helpful in future clinical practices.

[Research on the relationship between levels of soluble cluster of differentiation 40 ligand, matrix metalloproteinase 9 and pregnancy-associated plasma protein A in serum and stability of carotid plaques].

OBJECTIVES: To study the relationship between serum levels of some inflammatory markers and stability of carotid plaques in the patients with carotid plaques and evaluate the ability of each serum marker in identifying vulnerable carotid plaques. METHODS: The study included 65 consecutive patients with carotid plaques confirmed by imaging examinations from March 2008 to March 2010. All the patients were classified as stable plaques group (n = 21) and unstable plaques group (n = 44) according to the characteristic findings of the plaques in MRI such as the thickness of fibrous cap, the existence of large lipid core and the intra-plaque hemorrhage. The patients of unstable plaques group were further classified as unruptured plaques group (n = 29) and rupture plaques group (n = 15) according to the integrity of fibrous cap. Serum levels of soluble cluster of differentiation 40 ligand (sCD40L), matrix metalloproteinase 9 (MMP-9) and pregnancy-associated plasma protein A (PAPP-A) were determined by ELISA. RESULTS: Serum levels of sCD40L and MMP-9 in patients of unstable plaques group, unruptured plaques group and rupture plaques group were all significantly enhanced compared to individuals of stable plaques group (SCD40L: χ(2) = 6.45, 12.04 and 16.23, P < 0.01; MMP-9; F = 2.55, 5.10 and 4.69, P < 0.05). Serum levels of PAPP-A in patients of unstable plaques group and rupture plaques group were all significantly enhanced compared to individuals of stable plaques group (χ(2) = 11.71 and 13.55, P < 0.05). Serum levels of PAPP-A in patients of rupture plaques group were significantly enhanced compared to individuals of unruptured plaques group (χ(2) = 13.19, P = 0.000). sCD40L ≥ 673.22 ng/L (OR = 22.47, 95%CI: 2.11 - 239.81, P = 0.010), MMP-9 ≥ 84.09 µg/L (OR = 10.01, 95%CI: 1.74 - 57.78, P = 0.010) and PAPP-A ≥ 0.101 µg/L (OR = 14.29, 95%CI: 2.69 - 75.90, P = 0.002) were all significantly correlated with the vulnerability of carotid plaques. CONCLUSIONS: There appear to be a relationship between the serum levels of sCD40L, MMP-9 and PAPP-A and the stability of carotid plaques in patients with carotid plaques. High serum levels of the above-mentioned markers may indicate that the plaques were vulnerable or ruptured.

[Endovascular management of symptomatic carotid stenosis combined with kinking].

OBJECTIVE: To study the necessity, feasibility, security of carotid angioplasty and stenting (CAS) for symptomatic carotid stenosis combined with kinking. METHODS: Twelve patients with symptomatic carotid stenosis and kinking demonstrated by digital subtraction angiography (DSA) received CAS from December 2003 to December 2009. There were 9 male and 3 female patients, age ranged from 59 to 77 years (mean 69.3 years). All the patients' clinical, imaging, intervention and follow up data were collected and analyzed. RESULTS: All CAS procedures were successfully performed with 14 self-expandable stents placed. The mean degree of stenosis was reduced from 85.6% before stenting to 11.2% after stenting, the angle of kinking, according to Metz' category, were improved from less than 90° to more than 120° in each case. No perioperative procedure related stroke and transient ischemic attack (TIA) occurred. The clinical symptoms and signs of cerebral ischemia were improved or disappeared for all patients. During follow-up of these 12 patients for 6 to 72 months, one patient experienced ipsilateral carotid territory TIA and another patient experienced contralateral carotid territory TIA. DSA follow up of 5 patients demonstrated 1 case with in-stent restenosis and arterial kinking remote to the stent of internal carotid artery. CAS were performed again and CT angiography follow up demonstrated no kinking and restenosis 2 years after the intervention. Duplex scan of the other 7 patients demonstrated neither kinking nor restenosis. CONCLUSIONS: CAS seems to be feasible and safe for the patients with symptomatic kinking and stenosis, and maybe helpful to lower the risk of cerebral ischemia, but further study is needed.

Typical subdural contrast effusion secondary to endovascular treatment of a pediatric pial arteriovenous fistula.

Subdural contrast effusion secondary to endovascular treatment is exceptionally rare and might be mistaken as subdural hematoma because of similar hyperattenuation on computer tomography. The authors present the case of a 13-month-old girl with a history of increased head circumference and developmental retardation. Cerebral digital subtraction angiography showed a high-flow pial arteriovenous fistula fed by multiple arteries on the right cerebellar surface, with occlusion of the right sigmoid sinus and severe stenosis of the left sigmoid sinus. Staged endovascular treatments were performed to eliminate the fistula. Follow-up head computer tomography scans performed 3 h after both procedures demonstrated typical high-density subdural effusion with computer tomography attenuation value similar to hemorrhage. These effusions did not aggravate the condition and disappeared spontaneously 32 h after the first treatment and 29 h after the second, respectively.

Discovery of Pyrrole-imidazole Polyamides as PD-L1 Expression Inhibitors and Their Anticancer Activity via Immune and Nonimmune Pathways.

In recent years, PD-1 immune checkpoint inhibitors based on monoclonal antibodies have revolutionized cancer therapy, but there still exist unresolved issues, such as the high cost, the relatively low response rates, and so on, compared with small-molecule drugs. Herein a type of pyrrole-imidazole (Py-Im) polyamide as a small-molecule DNA binder was designed and synthesized, which could competitively bind to the same double-stranded DNA stretch in the PD-L1 promoter region as the STAT3 binding site and thus downregulate PD-L1 expression. It was demonstrated that the Py-Im polyamides directly caused apoptosis in tumor cells and retarded cell migration in the absence of T cells through inhibiting the Akt/caspase-3 pathway. Also, in a coculture system, they enhanced the T-cell-mediated killing of tumor cells by the reversal of immune escape. Because such polyamides induced antitumor effects via both immune and nonimmune pathways, they could be further developed as promising PD-L1 gene-targeting antitumor drugs.

[Endovascular treatment of ruptured and unruptured intracranial very small aneurysms].

OBJECTIVE: To evaluate the feasibility and safety of endovascular treatment of ruptured and unruptured intracranial very small aneurysms (< or = 3 mm in maximal diameter). METHODS: Forty-eight intracranial very small aneurysms in 44 patients treated with endovascular therapy from June 2001 to August 2009 were reviewed retrospectively in clinical, imaging, interventional and follow-up data. Among 44 patients, there were 20 males and 24 females with a mean age of 57.8 years old. The Hunt-Kosnik grade was as follows: Grade 0 (n = 11); Grades I & II (n = 23); Grades III & IV (n = 9); and ungraded (n = 1). The sizes of 48 aneurysms were not more than 3 mm in maximal diameter. The locations of aneurysms were as follows: ACoA (n = 11), MCA (n = 8), PCoA (n = 14), ICA (n = 12), pericallosal artery (n = 1), VA (n = 1) and PICA (n = 1). Thirty-nine aneurysms were embolized with coil, of which 13 with stent assistance and 6 by balloon remodeling technique. The other 9 aneurysms underwent sole stent placement in parent artery. RESULTS: Among 39 coiling aneurysms, 100% occlusion was achieved in 9 aneurysms, 90% in 20, 80% in 9 and less than 80% in 1 respectively. Only one aneurysm ruptured during coiling. Two patients had transient hemiparesis and one patient had ataxia caused by bilateral cerebellar infarction postoperatively. All patients were clinically followed up for 4-90 months and no recurrent hemorrhage occurred. Thirteen patients received repeat angiography at 4-72 months post-treatment. And no radiological re-growth was detected. CONCLUSION: Endovascular treatment of ruptured and unruptured intracranial very small aneurysms seems to be technically feasible, relatively safe and practically effective.

[Endovascular treatment of micro-intracranial aneurysms: adverse factors of micro-catheterization and its relevant managements].

OBJECTIVES: To investigate adverse factors that may hinder successful placement and stabilization of the microcatheter during endovascular therapy of micro-intracranial aneurysms (≤ 3 mm in maximum diameter), and to explore the relevant managements. METHODS: Forty-six patients with fifty-one micro-intracranial aneurysms treated by endovascular therapy from June 2001 to October 2009 were retrospectively analyzed for their intervention data. RESULTS: Adverse factors of optimal micro-catheterization mainly included, tortuosity of the proximal vessels (PVs) and the parent artery (PA), relative large gap in diameter among the PVs, the PA and the microcatheter, relative large divergence in direction among the PVs, the PA and the aneurysm dome, and stent deployed in the PA. CONCLUSIONS: Carefully considering the direction of the PVs and the PA, the aneurysm's location and dome orientation, choosing the microcatheter and microwire after balancing among their physical properties, as well as utilizing balloon and/or stent assistance, can facilitate micro-catheterization during endovascular treatment of micro-intracranial aneurysms.

[Effect of different duration of clopidogrel pretreatment on platelet activation in patients undergoing stenting].

OBJECTIVE: To investigate the effect of two clopidogrel pretreatment duration on platelet activation in patients undergoing stenting. METHODS: From July 2006 to December 2007 40 elective carotid or vertebral artery stenting patients were assigned into two groups: Group A (n = 24) initiated clopidogrel (75 mg/d) > or = 5 d before stenting; group B (n = 16) initiated 3 - 4 days. Platelet-monocyte aggregates and fibrinogen receptors analyzed by flow cytometric, and platelet aggregation tests using optical aggregometry, as well as serum soluble CD40 ligand quantified by enzyme-linked immunosorbent assay were assessed in peripheral blood samples obtained immediately before and at 0.5, 18 h and 6 d after stenting. RESULTS: Platelet-monocyte aggregates, fibrinogen receptors and serum soluble CD40 ligand were higher in group B than in group A (14.59% vs 8.70%, P = 0.012; 4.87% vs 2.42%, P = 0.024; 5.79 microg/L vs 2.64 microg/L, P = 0.020) at 18 h after stenting. Serum soluble CD40 ligand was higher in group B than in group A (0.49 microg/L vs 0.31 microg/L, P = 0.033) at 0.5 h after stenting. CONCLUSIONS: Premedication before stenting with clopidogrel 75 mg/d merely 3 - 4 d may be insufficient to achieve adequate platelet inhibition, whereas clopidogrel initiated at least 5 d could obtain preferable clinical antiplatelet efficacy.