876 research outputs found
A systematic approach to the formulation of anti-onychomycotic nail patches
Nail patches have a potential role as drug carriers for the topical treatment of nail diseases such as onychomycosis, a common condition. O ur aim was therefore to develop a systematic and novel appr oach to the formulat ion of a simple drug -in-adhesive ungual patch. Twelve pressure -sensitive adhesives (PSAs), four backing membranes, two release liners and three drugs were screened for pharmaceutical and mechanical properties . From this initial screeni ng, two PSAs, two drugs, one backing membrane and one release liner were selected for further investigation. Patches were prepared by solvent -casting and characterised. The patches had good uniformity of thickness and of drug content, and showed minimal drug crystallisation during six month s of storage. Meanwhile, the d rug stability in the patch upon storage and patch adhesion to the nail was influenced by the nature of the drug, the PSA and the backing membrane . The reported methodology paves the way for a systematic formulation of ungual nail patches to add to the armamentarium of nail medicines . Further , from this work, the best patch formulation has been identified
Modeling the effect of rate and geometry on peeling and tack of pressure-sensitive adhesives
A model is developed for predicting separation along interfaces of pressure sensitive adhesives. Many authors have used the cohesive zone approach to solve such problems but the parameter calibration of such models remains uncertain. This study reports a novel method for determining such parameters. In addition, it provides crucial evidence for the suitability of the cohesive zone model approach in modelling interface fractures. Peel tests were performed at various rates using specimens which consisted of a polyester backing membrane supporting an acrylic pressure-sensitive adhesive (PSA) adhered to a polyethylene substrate. Interfacial separation of the PSA from the polyethylene substrate was observed. Finite element (FE) peeling simulations were conducted which modeled the backing-membrane as an elasto-plastic power-law material, the adhesive as a viscoelastic material and the interfacial properties with a cohesive zone model (CZM). The material properties of the backing membrane and the pressure-sensitive adhesive were measured from tensile and stress relaxation experiments. The rate-dependent CZM parameters were measured directly from poker-chip probe-tack tests which were performed at pull-off speeds which corresponded to the rates employed for the peel tests. The effect of the PSA thickness and test rate on both tack and peel was investigated experimentally, as well as modeled numerically. Good agreement was found between the experimentally measured and numerically predicted peel forces for different peel angles, speeds and PSA thicknesses. In addition, it was proven that the rate dependence observed in the peel and probe-tack data was dominated by the rate dependence of the interface properties, i.e. the time dependence of the two CZM parameters of maximum stress and fracture energy, rather than the time-dependent bulk viscoelasticity of the PSA peel arm
Flow-Aware Elephant Flow Detection for Software-Defined Networks
Software-defined networking (SDN) separates the network control plane from the packet forwarding plane, which provides comprehensive network-state visibility for better network management and resilience. Traffic classification, particularly for elephant flow detection, can lead to improved flow control and resource provisioning in SDN networks. Existing elephant flow detection techniques use pre-set thresholds that cannot scale with the changes in the traffic concept and distribution. This paper proposes a flow-aware elephant flow detection applied to SDN. The proposed technique employs two classifiers, each respectively on SDN switches and controller, to achieve accurate elephant flow detection efficiently. Moreover, this technique allows sharing the elephant flow classification tasks between the controller and switches. Hence, most mice flows can be filtered in the switches, thus avoiding the need to send large numbers of classification requests and signaling messages to the controller. Experimental findings reveal that the proposed technique outperforms contemporary methods in terms of the running time, accuracy, F-measure, and recall
Distribution of Mode I Stress Intensity Factors for Single Circumferential Semi-Elliptical Crack in Thick Cylinder
In this paper, mode I stress intensity factors (SIFs) are calculated numerically by finite element software ANSYS, for a single semi-elliptical circumferential crack on a thick cylinder. The examined cracks were located either on the external or internal surface of the cylinder and subjected to two different types of loadings, tension and internal pressure, applied separately. To present results in a more comprehensive form, dimensionless analysis is used, and a wide variation limit of parameters that define the crack geometry is considered. The ratio of crack depth to crack length ranging between 0.4 to 1.2, the ratio of crack depth to cylinder wall thickness vary between 0.2, 0.5 and 0.8, and the ratio of the cylinder wall thickness to the cylinder internal radius 0.25. Based on the obtained results, distributions of SIFs found to be symmetric along the crack front. The location where the maximum SIFs on the crack front attained is strongly affected by the change of aspect ratio, and external cracks generally exhibit a higher SIFs than those of internal cracks. It is also found a significant effect for the relative depth of the crack on SIFs value, which could accelerate the fracture process
Respiratory effects of propofol-ketamine and propofl-fentanyl combinations for total intravenous anaesthesia
propofol combined with other intravenous analgesic agents has been used as the sole anaesthetic agent to provide hypnosis and analgesia for various minor and major surgeries. However, because it lacks analgesic property, propofol in large doses causes respiratory depression. Combination of propofol with other analgesic agents reduces the dose of propofol necessary for procedural sedation. Objectives: This study evaluated the respiratory effects of two drug combinations: propofol-ketamine and propofol-fentanyl used as the sole anaesthetic agents. Method: one hundred and eight adults aged 18 to 50 years of either gender with ASA physical status I & II, randomly grouped into K and F, comprising of 54 patients each. Group K received propofol-ketamine while group F received propofol-fentanyl for induction and maintenance of anaesthesia. Respiratory Rate (RR) and Oxygen saturation (SpO were recorded before and one 2) minutes after induction of anaesthesia and thereafter every five minutes till the end of procedure and at recovery till the patient is fully recovered. Results: Demographic and clinical characteristics such as age, sex, weight, duration of surgery, types of surgical procedures and volumes of drugs used were comparable between the two groups. Fall in respiratory rate was greater in propofol-fentanyl group compared to propofol-ketamine group during maintenance and early postoperative period (p<0.05). Conclusion: Both propofol-ketamine and propofolfentanyl combinations produced safe and effective anaesthesia. Propofol-ketamine results in a more stable respiratory profile
A Retrospective Study of Common Diseases of Animals in a Private Clinic in Kaduna Metropolitan
Data from clinical records of ECWA Veterinary Clinic, Kaduna, were retrieved for diseases of livestock retrospectively over a period of 10 years (January1997 – December 2006). The data was analyzed using descriptive statistics. The results indicate that a total of 5296 cases were handled during the 10 year study period and 48 different disease conditions werediagnosed and treated. Of the 48 disorders, Helminthosis appeared to be the most common disease condition with 2177(41%) of all cases handled, followed by Piroplasmosis 771(14.2%), Myiasis 572(10.9%), Bacterial infections 538(10.7%), Ectoparasitism 318(6%), Canine parvoviral enteritis267(5.04%), Mange 242(4.7%), Traumatic injury 1 3 2 ( 2 . 5 1%) , S e p t i c emi a 8 0 ( 1 . 5%) a n d Dermatomycosis 40(0.55%). Other conditionshandled included Caudectomy 20(0.38%), hematoma 16(0.30%), castration 15(0.28%), canine distemper 11(0.21%), food poisoning, fracture, infectious canine hepatitis presenting 10 (0.19%) each. Othersinclude Orchidectomy 7(0.13%), pinnal ulcers 6(0.11%), malnutrition 5(0.09%), organophosphate poisoning and still were handled 4 (0.08%) times each, while Conjuctivitis and Orchitis were handled only 3(0.06%) times each. There are other 11 diseases grouped as A which appeared only twice each throughout the study totaling 22(0.42%) and other 13 diseases grouped as B appeared only once each totaling 13(0.25%). Canine species were the most presented of all animal species with 4413(83.3%), followed by bovine 383(7.23%), ovine 260(4.9%), caprine 170(3.2%), porcine 50(0.94%), feline 19(0.35%) and equine 1(0.02%). Lack of routine de-worming and location of the clinic is responsiblefor this outcome. The findings elucidate the relevance of private veterinary clinics in disease reporting.Keywords: Common diseases of livestock, Helminthosis, Piroplasmosis, ECWA Veterinary clinic, Kaduna Stat
Comparing computer-generated and pathologist-generated tumour segmentations for immunohistochemical scoring of breast tissue microarrays
BACKGROUND: Tissue microarrays (TMAs) have become a valuable resource for biomarker expression in translational research. Immunohistochemical (IHC) assessment of TMAs is the principal method for analysing large numbers of patient samples, but manual IHC assessment of TMAs remains a challenging and laborious task. With advances in image analysis, computer-generated analyses of TMAs have the potential to lessen the burden of expert pathologist review. METHODS: In current commercial software computerised oestrogen receptor (ER) scoring relies on tumour localisation in the form of hand-drawn annotations. In this study, tumour localisation for ER scoring was evaluated comparing computer-generated segmentation masks with those of two specialist breast pathologists. Automatically and manually obtained segmentation masks were used to obtain IHC scores for thirty-two ER-stained invasive breast cancer TMA samples using FDA-approved IHC scoring software. RESULTS: Although pixel-level comparisons showed lower agreement between automated and manual segmentation masks (κ=0.81) than between pathologists' masks (κ=0.91), this had little impact on computed IHC scores (Allred; [Image: see text]=0.91, Quickscore; [Image: see text]=0.92). CONCLUSIONS: The proposed automated system provides consistent measurements thus ensuring standardisation, and shows promise for increasing IHC analysis of nuclear staining in TMAs from large clinical trials
A systematic approach to the formulation of anti-onychomycotic nail patches
Nail patches have a potential role as drug carriers for the topical treatment of nail diseases such as onychomycosis, a common condition. Our aim was therefore to develop a systematic and novel approach to the formulation of a simple drug-in-adhesive ungual patch. Twelve pressure-sensitive adhesives (PSAs), four backing membranes, two release liners and three drugs were screened for pharmaceutical and mechanical properties. From this initial screening, two PSAs, two drugs, one backing membrane and one release liner were selected for further investigation. Patches were prepared by solvent-casting and characterised. The patches had good uniformity of thickness and of drug content, and showed minimal drug crystallisation during six months of storage. Meanwhile, the drug stability in the patch upon storage and patch adhesion to the nail was influenced by the nature of the drug, the PSA and the backing membrane. The reported methodology paves the way for a systematic formulation of ungual nail patches to add to the armamentarium of nail medicines. Further, from this work, the best patch formulation has been identified
Cetuximab Conjugated with Octreotide and Entrapped Calcium Alginate-beads for Targeting Somatostatin Receptors.
There is a need to formulate oral cetuximab (CTX) for targeting colorectal cancer, which is reported to express somatostatin receptors (SSTRs). Therefore, coating CTX with a somatostatin analogue such as octreotide (OCT) is beneficial. Alginate was used to coat CTX to facilitate delivery to the gastrointestinal tract (GIT). This study aimed to deliver CTX conjugated with OCT in the form of microparticles as a GIT-targeted SSTR therapy. Both CTX and OCT were conjugated using a solvent evaporation method and the conjugated CTX-OCT was then loaded onto Ca-alginate-beads (CTX-OCT-Alg), which were characterized for drug interactions using differential scanning calorimetry (DSC), and Fourier transform infrared spectra (FTIR). Moreover, the morphology of formulated beads was examined using a scanning electron microscope (SEM). The drug content and release profile were studied using UV spectroscopy. Finally, in vitro cytotoxicity of all compounds was evaluated. The results showed homogenous conjugated CTX-OCT with a diameter of 0.4 mm. DSC showed a delay in the OCT peak that appeared after 200 °C due to small polymer interaction that shifted the OCT peak. Moreover, FTIR showed no prominent interaction. SEM showed clear empty cavities in the plain Ca-alginate-beads, while CTX-OCT-Alg showed occupied beads without cavities. CTX-OCT-Alg had a negligible release in 0.1 N HCl, while the CTX-OCT was completely released after 300 min in phosphate buffer pH 7.4. All formulations showed good antiproliferative activity compared with free drugs. The formulated CTX-OCT-Alg are a promising platform for targeting colorectal cancer through GIT
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