Vascularized fascial patch for repair of suboccipital dural defect

The capabilities of current protein structure prediction methods have been assessed from the outcome of a set of blind tests. In comparative modeling, many of the numerical methods did not perform as well as expected, although the resulting structures are still of great practical use. The new methods of fold identification ('threading') were partially successful, and show considerable promise for the future. Except for secondary structure data, results from traditional ab initio methods were poor. A second blind prediction experiment is underway, and progress in all areas is expected.     

Determination of lumped rate coefficients of proteins: Effect of adsorption

The equilibria and kinetics of adsorption of lysozyme and bovine serum albumin on the Fractogel-EMD tentacle-type cation exchanger and the Fractogel-TSK conventional cation exchanger have been studied experimentally by batch stirred-tank method. Adsorption equilibrium data corresponded well to the Langmuir isotherm. For both proteins, the tentacle-type exchanger exhibited a higher binding capacity than the conventional exchanger. This is attributed to the flexibility of the functional groups in the tentacle-type exchanger which enhance optimal electrostatic interactions. The dynamic data were analyzed by a simplified data model which lumped mass transfer resistances and intrinsic adsorption kinetics into a single rate constant. For both proteins, it was found that the tentacle-type exchanger showed a smaller lumped rate coefficient than the conventional exchanger. The difference in the values of the lumped rate coefficients was shown to be due to the influence of nonlinear equilibrium constants rather than due to any difference in rate of adsorption.     

Treatment of overactive bladder syndrome and detrusor overactivity

The overactive bladder syndrome is a relatively new-term defined by the International Continence Society in 2002. Previous definitions were based on urodynamic diagnoses; however, the overactive bladder syndrome is a symptomatic diagnosis with urgency as the cornerstone symptom, thus allowing treatment to be initiated by primary care physicians before embarking on complex investigations. It affects millions of people worldwide and has considerable economic costs. Its aetiology is unknown but some people suggest that it may be a nerve-related problem while others suggest that it may be a muscle-related problem. The true cause probably lies somewhere between the two theories. With this in mind, treatment is aimed at relief of symptoms and improving quality of life. Conservative treatments combined with antimuscarinic drugs are the main treatment for overactive bladders. There are many antimuscarinics available, with several under development, which have different specificities for the muscarinic receptors. Other drugs have also been tried but with limited success.If conservative and oral medical treatments fail, the options include intravesical therapy, neuromodulation or major surgery. However, urodynamics are essential for patients referred for these treatments, which are mainly initiated by specialists rather than primary care physicians. The aim of this review is to give an overview of the overactive bladder and detrusor overactivity, their diagnosis and treatment options.     

Model reduction via Schur decomposition

A simple procedure for model reduction based upon a Schur decomposition of a given system is presented. The obtained partitioned system allows the combination of singular perturbation and aggregation approaches     

Microvascular soft-tissue coverage and distraction osteosynthesis for lower-extremity salvage

In our attempts to salvage massive lower-extremity injuries, even in the presence of severe peripheral vascular pathology, adequate soft-tissue coverage is no longer a limiting factor due to recent advances in microvascular composite tissue transfer. Restoration of tibial continuity without shortening has emerged as the last obstacle in the formidable task of salvaging lower extremities with grade III B and III C defects. Proposed solutions to this problem include conventional free cancellous bone-grafting applicable to small defects only, vascularized bone grafts, or shortening of the leg with subsequent elongation using the Ilizarov technique. We present our experience with 3 consecutive cases of lower-limb salvage, utilizing a new approach in which microsurgical soft-tissue reconstruction has been combined with bony reconstruction by distraction osteosynthesis. Bone transport by distraction osteosynthesis under a free flap performed while preserving the initial limb length throughout the treatment period proved to be superior to other methods in selected cases and is presented as a new technique for the management of problematic lower-limb injuries.     

Single Phase Flow Pressure Drop in Glass Ballotini Particulate Beds

A study was made of pressure drop during single fluid phase flow to determine the pressure drop characteristic of the porous media (glass ballotini particulate beds) for coalescence. It is also served to check the reproducibility of the packing technique, and to detect any foreign particulate matter or re-arrangement of the individual particles in the coalesce bed. Furthermore these data provided a basis for comparison with that during two-phase flow with coalescence. For spherical particle the modified Carman-Kozeny equation was applied; the commonly accepted value for Kozeny constant is 5.0. However, K, depends on, among other factors, the structure of the bed, voidage fraction, particle shape, tortuosity, superficial velocity, bed depth, particle size, and wall effect.     

Dynamics-based amplification of RNA function and its characterization by using NMR spectroscopy

The ever-increasing cellular roles ascribed to RNA raise fundamental questions regarding how a biopolymer composed of only four chemically similar building-block nucleotides achieves such functional diversity. Here, I discuss how RNA achieves added mechanistic and chemical complexity by undergoing highly controlled conformational changes in response to a variety of cellular signals. I examine pathways for achieving selectivity in these conformational changes that rely to different extents on the structure and dynamics of RNA. Finally, I review solution-state NMR techniques that can be used to characterize RNA structural dynamics and its relationship to function.     

Sharing Malaysian experience with the development of biotechnology-derived food crops

Biotechnology-derived food crops are currently being developed in Malaysia mainly for disease resistance and improved post harvest quality. The modern biotechnology approach is adopted because of its potential to overcome constraints faced by conventional breeding techniques. Research on the development of biotechnology-derived papaya, pineapple, chili, passion fruit, and citrus is currently under way. Biotechnology-derived papaya developed for resistance to papaya ringspot virus (PRSV) and improved postharvest qualities is at the field evaluation stage. Pineapple developed for resistance to fruit black heart disorder is also being evaluated for proof-of-concept. Other biotechnology-derived food crops are at early stages of gene cloning and transformation. Activities and products involving biotechnology-derived crops will be fully regulated in the near future under the Malaysian Biosafety Law. At present they are governed only by guidelines formulated by the Genetic Modification Advisory Committee (GMAC), Malaysia. Commercialization of biotechnology-derived crops involves steps that require GMAC approval for all field evaluations and food-safety assessments before the products are placed on the market. Public acceptance of the biotechnology product is another important factor for successful commercialization. Understanding of biotechnology is generally low among Malaysians, which may lead to low acceptance of biotechnology-derived products. Initiatives are being taken by local organizations to improve public awareness and acceptance of biotechnology. Future research on plant biotechnology will focus on the development of nutritionally enhanced biotechnology-derived food crops that can provide more benefits to consumers.     

Improvement of plasma lipoprotein profiles during high-flux dialysis

Patients undergoing maintenance hemodialysis therapy have increased mortality due to cardiovascular disease. One possible etiologic factor for this increased mortality is the lipid abnormalities associated with chronic renal failure. These include elevated triglyceride (TG) and decreased high-density lipoprotein (HDL) concentrations. Lipoprotein profiles of patients undergoing chronic hemodialysis with either saponified cellulose ester (CE) (N = 9) or polysulfone (PS) high-flux dialysis membranes (N = 10) were compared. Patients in each group received similar amounts of heparin during the dialysis. CE-dialyzed patients showed no alteration in serum TG, HDL, low-density lipoprotein, or total cholesterol when predialysis and postdialysis values were compared. PS patients, on the other hand, had a significant decrease in TG concentrations (P < 0.01) as well as a significant rise in HDL (P < 0.01). These changes might signify activation of lipoprotein lipase (LPL) during dialysis. LPL activity in PS sera was significantly greater than LPL in CE sera. Moreover, sera from PS patients inhibited LPL much less than did sera from CE patients. These findings suggest that a circulating substance not dialyzable with cellulosic membranes inhibits LPL in uremic subjects and is removed during dialysis with a PS membrane. Alternatively, the greater biocompatibility of PS may produce less LPL inhibitory cytokines during dialysis. The improvement of lipoprotein profiles in patients receiving dialysis with PS membranes may, in the long term, lead to less morbidity and mortality from atherosclerotic disease.     

Strength of resin-coated-adhesive-bonded double lap-shear pultrusion joints at ambient temperature

The inherited adhesion limitation of polyester and vinyl ester resin-based pultruded GFRP makes pultrusions difficult to bond, especially when a thixotropic adhesive is used. While such an adhesive is necessary for gap filling, it has a limited wettability. Therefore, coating the adherend with low-viscosity epoxy resin, prior to bonding, improves wetting and hence increases joint strength. The paper describes the experimental methodology to achieve this, using double lap-shear (DLS) joints with various materials combinations. A significant strength improvement was reached as a result of coating the inner adherend in conjunction with using a “high adhesion” outer adherend. To further understand the effect of coating, numerical stress analysis was undertaken, including preliminary micro-models representing the composite/adhesive interface as well as overall DLS models.