capillary electrophoresis (CE) with indirect UV detection is an interesting analytical method for the analysis of drugs and pharmaceuticals. Good and reproducible capillary quality is needed to develop robust methods and to facilitate method transfer in CE. It is widely accepted that preconditioning procedures are indispensable in capillary electrophoresis in order to achieve reproducibility of migration times and peak areas.In order to explore different aspects of this technique, a set of experiments were performed using vigabatrin as a model drug. The effects of capillary rinsing between each run was investigated using basic (NaOH 0.1 M) and acidic (phosphoric acid 0.1 M)-wash cycles. The results of 10 consecutive injection of the model drug after each of the two wash cycles, reveal that more reproducible results obtained when acid-wash cycle was performed as a capillary conditioning protocol. The higher pH changes during basic-wash cycle and its effects on the characteristics of the capillary inner surface were suggested as a source of greater variation between consecutive runs.

A capillary rheometer was designed and constructed to carry out studies on the flow behaviour of viscous non-Newtonian fluids. Two capillary tubes were attached to the pressure chamber which increase the accuracy of the rheological measurements ( power law index as well as consistency index). By employing two capillary tubes, the power law index can be calculated directly from the measuring values and the accuracy of consistency index increases as well. capillary tubes with different diameters and various lengths can be used and a wide range of shear rates can be covered by using different tubes. Tests were conducted with solutions of sodium carboxymethyl cellulose (CMC) of different concentrations and various temperatures. The CMC solutions exhibited characteristics typical of power law model of non-Newtonian fluids. The measurements illustrated that the consistency index varies significantly with both concentration and temperature. Increasing concentration enhances consistency index while promoting temperature has a reverse effect. Also concentration has noticeable effect on power law index. As concentration increases the power law index decreases. The effect of temperature on power law index is negligible.

In well fractured carbonate reservoirs the gas/oil gravity drainage from the gas-invaded zone is the dominating oil producing process. When the gravitational forces exceed the capillary forces. the matrix blocks, which are surrounded by gas, will release their oil.The results of our experimental works reveal that, depending on the interfacial tension, spreading coefficient, rock wet ability, and surface roughness. there is a critical fracture aperture size, tfc Rock wet ability. Surface roughness and spreading coefficient play their rules in formation of oil droplets. while the maximum size of the droplet is controlled by the amount of surface tension. When the fracture aperture is more than tfc the continuity is via solid compressed spacers and/or oil film around them. which at actual reservoir conditions may be considered as non-effective capillary continuity.Whereas for the case that the fracture aperture is less than its critical value, the capillary continuity is mainly through liquid bridges, which due to their high transmissibility will result in an effective capillary continuity between blocks.Two new definitions for horizontal fracture capillary pressure based on the type of capillary continuity have been presented. The Laplace formula and pressure difference between the fracture gas and the matrix oil may be used for the calculation of fracture capillary pressure for non-effective and effective continuity, respectively.

The kinetics of capillary rise follows the Lucas-Washburn equation. capillary flow is studied in core-spun yarns by image analysis of coloured liquid rising into the core-spun yarn and the distance of liquid rise was determined as a function of time. The great variations of the experimental results in the cross and along the yarns are attributed to the yarn heterogeneity of the interfibre space. Yarn construction features, such as twist, linear density, and pretension of core component of core-spun yarns are shown to be related to the rate of liquid transport in such fibre assemblies. The liquid transport properties of yarns in general provide useful information about fibre orientation in yarns. The results show that the continuity of capillaries formed by the fibres decreases either by random arrangement of fibres due to low pretension of core component or by increasing yarn twist. Also, decrease in the size of capillaries was governed by three parameters, namely; increased pretension of core component, decreased linear density of core component, and increased yarn twist. The present study indicates that an appropriate choice in production parameters of core-spun yarns is all important in obtaining the desired properties of capillary rise.

Dear Editor-in-Chief Hemangiomas are considered as vascular malformations categorized by the type of vascular channel to capillary, cavernous, venous or arteriovenous (1). Their usual locations are soft tissue, cutaneous or subcutaneous tissue and bone especially vertebra (2). However, intradural extramedullary hemangiomas are rare and most of them fall in cavernous type category. Hereby, we report a woman with intradural extramedullary capillary hemangioma which is exceedingly rare.The patient was a 45-yr-old woman with thoracic spine pain for 6 month. She also had progressive parasthesia of lower limbs without muscular weakness or sphincteric problems. The spinal magnetic resonance imaging revealed a rather wellcircumscribed intradural extramedullary mass at T9-T10 level with a broad dural base mimicking dural tail sign suggestive for meningioma. The mass had isointensity at T1 weighted images and hyperintensity at T2 weighted images. It was homogenously intensified after contrast administration (Figure 1).Then, the patient underwent surgery with preoperative diagnosis of meningioma. After laminectomy, an intradural mass was explored which was spongy and soft. Resection of mass led to bleeding controlled by cautherizing.

Background: Lobular capillary hemangioma is a benign vascular tumor commonly found within the skin and upper respiratory mucosa and has rarely been reported within the trachea. The first case was reported by Irani et al. in 2003 and since then, less than 20 cases have been described. That’s why the characteristics and treatments remain relatively unknown. Case Presentation: A 53-year-old woman was symptomatic of recurrent episodes of hemoptysis associated with paroxysmal dyspnea. Physical examination, routine blood investigations, and chest x-ray were normal. The flexible bronchoscopy showed a polypoid bleeding lesion arising from the right lateral wall of the middle third of the trachea. Tumor biopsy was not performed considering an eventual bleeding risk. Computed tomography scanning showed a vascular, endotracheal budding tissue process without peritracheal or distant extension. A rigid bronchoscopy was performed for diagnostic and therapeutic purposes. A 10-millimeter bronchoscope was used. A rigid coring technique was performed to remove the tumor. A minimal bleeding was completely controlled after diode laser treatment. There were no complications during or after the procedure. Pathology revealed no malignancy and the diagnosis of lobular capillary hemangioma was confirmed. At a 6-month follow-up, the patient was asymptomatic and the endoscopic control did not show any tumor recurrence. Conclusion: The lobular capillary hemangioma is a benign tumor rarely observed in the trachea. Clinical features are not specific and the short-term prognosis depends on tumor size. Considering its benign nature, tumor removal by interventional bronchoscopy should be proposed as the first-line treatment.