Evaluation of Biodegradation of Pineapple Leaf Fiber Reinforced PVA Composites

Composites of polyvinyl alcohol (PVA) reinforced with different weight percentages of pineapple leaf fibers (PALF) were fabricated and evaluated for biodegradation by soil burial test and plate test. FTIR analysis indicated the existence of a chemical interaction between PVA and PALF. The water uptake study showed that the composites with higher fiber content displayed high tensile strength and brittleness but possessed lower water uptake potential. In the soil burial test, the composites with low matrix to filler ratios exhibited higher rates of degradation as evident by the associated decrease in molecular weights. Plate test performed using Pseudomonas putida showed that the composites were susceptible for degradation by bacteria. The results of this study indicated that PALF-reinforced PVA composites were completely biodegradable and could find potential applications in industries such as agriculture and packaging and safely disposed after use without causing environmental damage.     

Profiling the operational behavior of OS device drivers

As the complexity of modern Operating Systems (OS) increases, testing key OS components such as device drivers (DD) becomes increasingly complex given the multitude of possible DD interactions. Currently, DD testing entails a broad spectrum of techniques, where static (requiring source code) and dynamic (requiring the executable image) and static-dynamic testing combinations are employed. Despite the sustained and improving test efforts in the field of driver development, DDs still represent a significant cause of system outages as the coverage is invariably limited by test resources and release time considerations. The basic factor is the inability to exhaustively assess and then cover the operational states, leading to releases of inadequately tested DDs. Consequently, if representative operational activity profiles of DDs within an OS could be obtained, these could significantly improve the understanding of the actual operational DD state space and help focus the test efforts. Focusing on characterizing DD operational activities while assuming no access to source code, this paper proposes a quantitative technique for profiling the runtime behavior of DDs using a set of occurrence and temporal metrics obtained via I/O traffic characterization. Such profiles are used to improve test adequacy against real-world workloads by enabling similarity quantification across them. The profiles also reveal execution hotspots in terms of DD functionalities activated in the field, thus allowing for dedicated test campaigns. A case study on actual Windows XP and Vista drivers using various performance and stability benchmarks as workloads substantiates our proposed approach.     

Combined experimental and analytical method for a realistic seismic qualification of equipment

The seismic qualification of equipment/structures are, in general, carried out either exclusively by analysis or exclusively by testing using a shake table. The analytical methods have the risk of the model not being a true reflection of the structure unless very elaborate modelling techniques are used. Even with an elaborate model there are many idealisations made which may not actually be realised in practice. The shake-table testing, avoids the modelling deviations to a large extent, but is also not without drawbacks. The important ones are the cost and the availability of a shake table of the required size and capacity. The shake-table testing is also carried out on the isolated equipment without the piping/structural connections from other components. The present paper suggests a combined experimental and analytical method on the ‘as installed’ equipment as an attractive alternative which overcomes the above drawbacks. In contrast to the existing practice of using the experimental results just to validate the analytical model, the suggested method uses the experimentally obtained dynamic characteristics of the ‘as installed’ equipment to obtain the response to the design seismic load. The paper brings out through an example of a simple storage tank which is too heavy for a shake table, the large deviations in its actual behaviour vis-à-vis an idealised analytical model.     

Engineering the system of communication for safer surgery

Communication failures are a leading cause of error in surgery. Researchers and practitioners have therefore developed different interventions to improve communications, such as team briefing and pre-operative patient checklists. These different methods have clear merit. However, they have only dealt with portions of a complex system. Consequently, disparate interventions of varying kinds may not integrate and build an effective system of communication. We argue that a new view of communication is needed to improve safety in surgery; the view that communication is more fundamentally as a property of the whole system of work rather than confined to interpersonal exchanges. Rather than simply add an intervention to the system, interventions should integrate into the system. To achieve this, we propose a practical strategy to re-engineer the system of communication for surgery. This demands an analysis of the immediate informational needs within the system of interest, and an account of the wider system and those ergonomic and human factors shaping the performance of communicators. We illustrate the application of the method and refer to potential improvements in safety.     

Good trellises for IC implementation of Viterbi decoders for linearblock codes

This paper investigates trellis structures of linear block codes for the integrated circuit (IC) implementation of Viterbi decoders capable of achieving high decoding speed while satisfying a constraint on the structural complexity of the trellis in terms of the maximum number of states at any particular depth. Only uniform sectionalizations of the code trellis diagram are considered. An upper-bound on the number of parallel and structurally identical (or isomorphic) subtrellises in a proper trellis for a code without exceeding the maximum state complexity of the minimal trellis of the code is first derived. Parallel structures of trellises with various section lengths for binary BCH and Reed-Muller (RM) codes of lengths 32 and 64 are analyzed. Next, the complexity of the IC implementation of a Viterbi decoder based on an L-section trellis diagram for a code is investigated. A structural property of a Viterbi decoder called add-compare-select (ACS)-connectivity which is related to state connectivity is introduced. This parameter affects the complexity of wire-routing (interconnections within the IC). The effect of five parameters namely: (1) effective computational complexity; (2) complexity of the ACS-circuit; (3) traceback complexity; (4) ACS-connectivity; and (5) branch complexity of a trellis diagram on the very large scale integration (VLSI) complexity of a Viterbi decoder is investigated. It is shown that an IC implementation of a Viterbi decoder based on a nonminimal trellis requires less area and is capable of operation at higher speed than one based on the minimal trellis when the commonly used ACS-array architecture is considered     

Progressive ocular toxoplasmosis in patients with acquired immunodeficiency syndrome

We studied two patients, a 43-year-old Hispanic man with a one-year history of acquired immunodeficiency syndrome (AIDS) and a 34-year-old Hispanic man with newly diagnosed AIDS. Both had necrotizing retinitis that progressed to panophthalmitis and orbital cellulitis. Toxoplasmosis was not diagnosed in the first patient early in the course of the disease. The second patient had a history of toxoplasmic retinochoroiditis. Despite anti-toxoplasmosis therapy, visual acuity deteriorated to no light perception in both patients. Diagnostic biopsy of the eye wall was performed on the first patient and enucleation of the globe on the second. Toxoplasmic panophthalmitis and orbital cellulitis were diagnosed in each patient by light microscopy and confirmed by electron microscopy. When patients with AIDS develop necrotizing retinitis, toxoplasmosis must be considered in the differential diagnosis, along with cytomegalovirus retinitis, progressive outer retinal necrosis, and syphilitic retinitis. Unlike cytomegalovirus retinitis, progressive outer retinal necrosis, and syphilitic retinitis, however, toxoplasmosis can cause a progressive intraocular infection, panophthalmitis, and orbital cellulitis in patients with AIDS.     

Association of crescentic glomerulonephritis with membranous glomerulonephropathy: a report of three cases

Association of membranous glomerulonephropathy with crescentic glomerulonephritis is apparently extremely rare. We report three patients who had this combination. One patient had biopsy-proven membranous glomerulonephropathy thirteen months prior to sudden and rapid decline in renal function necessitating hemodialysis. A repeat renal biopsy showed a superimposed crescentic nephritis and antiglomerular (GBM) antibodies were demonstrable in the serum. A second patient had proteinuria of unknown duration and then developed renal failure. Renal biopsy showed crescentic nephritis with a fine granular glomerular immunofluorescence for IgG typical of membranous glomerulonephropathy. Anti-GBM antibodies were present in this patient's serum. The third patient presented with acute renal failure of moderate severity. A renal biopsy revealed crescentic nephritis, granular deposits of immunoglobulins, and epimembranous electron-dense deposits typical of membranous glomerulonephropathy. Although his creatinine clearance improved spontaneously, nephrotic syndrome has persisted and a repeat renal biopsy showed a progression of the membranous glomerulonephropathy with the disappearance of the crescentic lesions. The reason for this peculiar association of membranous glomerulonephropathy and crescentic glomerulonephritis is unclear. It is possible that deposition of immune-complexes along glomerular basement membrane may render the glomerulus more susceptible to additional injury from a variety of other agents. Alternatively, depostis formed in one disease could initiate release of normal or altered basement membrane material and lead to formation of anti-GBM antibodies and subsequent development.     

Idiopathic polypoidal choroidal vasculopathy of the macula

OBJECTIVE: The authors evaluated the clinical, fluorescein, and indocyanine green (ICG) angiographic characteristics of the macular variant of idiopathic polypoidal choroidal vasculopathy (IPCV). DESIGN: Observational case series. PARTICIPANTS: The records, photographs, and fluorescein and ICG angiograms of eight eyes of seven patients with IPCV lesions confined to the macula were reviewed. MAIN OUTCOME MEASURES: The visual acuity, fundus examination, fluorescein and ICG angiographic characteristics, and clinical course were compared. RESULTS: All patients demonstrated polypoidal lesions arising from macular choroidal vessels on ICG angiography. One patient had bilateral lesions. These lesions appeared hyperfluorescent in the early phases of both fluorescein and ICG angiography. Late-phase leakage was seen in cases associated with subretinal fluid or exudate. None of these patients demonstrated polypoidal lesions arising from the peripapillary choroidal circulation or peripapillary choroidal neovascularization. Three eyes with polypoidal lesions that were associated with subretinal fluid and exudates were treated with photocoagulation. Five eyes were not treated. Final visual acuity ranged from 20/20 to hand motions. Severe visual loss was associated with vitreous and subretinal hemorrhage, but this resolved without permanent severe visual loss in several cases. CONCLUSIONS: In the macular variant of IPCV, ICG and fluorescein angiography demonstrate characteristic macular polypoidal lesions without evidence of peripapillary lesions. The vascular origin of these polypoidal lesions appears to be the macular choroidal circulation. This is distinguished from classic IPCV, in which lesions appear to arise from the peripapillary choroidal circulation. Visual prognosis appears to be good, with most patients retaining visual acuity of 20/80 or better. If subretinal fluid or exudates reduce visual acuity, photocoagulation should be considered.