Finite element analysis of groundwater contamination

Includes bibliographical references.The purpose of this study was to develop a computational Finite Element model, validated by experimentation, to assist in the understanding of groundwater contamination problems. It was mainly aimed at studying the extent and manner of travel of contaminants in the saturated soil of unconfined aquifers which may be pumped by of wells

Conditional linearizability criteria for a system of third-order ordinary differential equations

We provide linearizability criteria for a class of systems of third-order ordinary differential equations (ODEs) that is cubically semi-linear in the first derivative, by differentiating a system of second-order quadratically semi-linear ODEs and using the original system to replace the second derivative. The procedure developed splits into two cases, those where the coefficients are constant and those where they are variables. Both cases are discussed and examples given

Decreasing Medical Complications for Total Knee Arthroplasty: Effect of Critical Pathways on Outcomes

BACKGROUND: Studies on critical pathway use have demonstrated decreased length of stay and cost without compromise in quality of care. However, pathway effectiveness is difficult to determine given methodological flaws, such as small or single center cohorts. We studied the effect of critical pathways on total knee replacement outcomes in a large population-based study. METHODS: We identified hospitals in four US states that performed total knee replacements. We sent a questionnaire to surgical administrators in these hospitals including items about critical pathway use and hospital characteristics potentially related to outcomes. Patient data were obtained from Medicare claims, including demographics, comorbidities, 90-day postoperative complications and length of hospital stay. The principal outcome measure was the risk of having one or more postoperative complications. RESULTS: Two hundred ninety five hospitals (73%) responded to the questionnaire, with 201 reporting the use of critical pathways. 9,157 Medicare beneficiaries underwent TKR in these hospitals with a mean age of 74 years (± 5.8). After adjusting for both patient and hospital related variables, patients in hospitals with pathways were 32% less likely to have a postoperative complication compared to patients in hospitals without pathways (OR 0.68, 95% CI 0.50-0.92). Patients managed on a critical pathway had an average length of stay 0.5 days (95% CI 0.3-0.6) shorter than patients not managed on a pathway. CONCLUSION: Medicare patients undergoing total knee replacement surgery in hospitals that used critical pathways had fewer postoperative complications than patients in hospitals without pathways, even after adjusting for patient and hospital related factors. This study has helped to establish that critical pathway use is associated with lower rates of postoperative mortality and complications following total knee replacement after adjusting for measured variables

Stem cell therapy for the treatment of early stage avascular necrosis of the femoral head: a systematic review

BACKGROUND: Avascular necrosis (AVN) of the femoral head (FH) is believed to be caused by a multitude of etiologic factors and is associated with significant morbidity in younger populations. Eventually, the disease progresses and results in FH collapse. Thus, a focus on early disease management aimed at joint preservation by preventing or delaying progression is key. The use of stem cells (SC) for the treatment of AVN of the FH has been proposed. We undertook a systematic review of the medical literature examining the use of SC for the treatment of early stage (precollapse) AVN of the FH, in both pre-clinical and clinical studies. METHODS: Data collected included: Pre-clinical studies – model of AVN, variety and dosage of SC, histologic and imaging analyses. Clinical studies – study design, classification and etiology of AVN, SC dosage and treatment protocol, incidence of disease progression, patient reported outcomes, volume of necrotic lesion and hip survivorship. RESULTS: In pre-clinical studies, the use of SC uniformly demonstrated improvements in osteogenesis and angiogenesis, yet source of implanted SC was variable. In clinical studies, groups treated with SC showed significant improvements in patient reported outcomes; however hip survivorship was not affected. Discrepancies regarding dose of SC, AVN etiology and disease severity were present. CONCLUSIONS: Routine use of this treatment method will first require further research into dose and quality optimization as well as confirmed improvements in hip survivorship

The effect of pegylation on the transfection activity of two homologous cationic cholesteryl cytofectins

Polyethylene glycol is being used increasingly to improve circulation times and enhance bioavailability of therapeutic molecules and nano sized macromolecular assemblies. Here, two homologous cationic cholesteryl cytofectins 3β[N-(N’,N’-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 3β[N- (N’,N’-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T) with 2 and 3 carbon spacer elements, respectively, have been formulated into liposomes with near equimolar amounts of dioleoylphosphatidyl ethanolamine (DOPE) and 2 and 5% polyethylene glycol2000 (PEG2000). Pegylated liposomes (80 - 150 nm diameter) formed electrostatic complexes with plasmid DNA in the 1.5:1 – 2.5:1 range of liposome (positive): DNA (negative) charge ratio, which afforded protection to the DNA cargo against serum nuclease digestion. Plasmid pGL3-containing pegylated lipoplexes were only weakly cytotoxic in the human embryonic kidney cell line HEK 293. Gene transfer experiments in this cell line confirmed that the homologue with the 3 carbon spacer Chol-T, is associated with higher transgene activity, a trend which has been previously observed in unpegylated lipoplexes. Furthermore, only a 15% drop in transfection activity was recorded in increase of pegylation level from 2 to 5 mole percent.Key words: Cationic cytofectin, gene transfer, polyethylene glycol, HEK 293

DETERMINATION OF TOTAL PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF DICHROSTACHYS CINERA, GUIERA SENEGALENSIS AND VITEX DONIANA

The present work was undertaken to determine the phenolic content and antioxidant capacity of three plants used in Sudanese folk medicine.The total phenolic content was measured by Folin Ciocalteau method using gallic acid as standard while the antioxidant capacity was based on the ability of these plant extracts to scavenge DPPH radical.High total phenolic content was detected in Dichrostachys cinera followed by Guiera senegalensis and Vitex doniana. Dichrostachys cinera exhibited the strongest antioxidant capacity with EC50 6.63 μg/ml, followed by Guiera senegalensis (7.74 μg/ml) and Vitex doniana (22.72 μg/ml). A significant linear correlation between total phenolic content and antioxidant capacity(R2=0.9957) confirmed that the phenolic phytoconstituents are responsible for the antioxidant activity.It can be concluded that the three surveyed plants could be potential sources of antioxidant agent

Life within chronic care: is this a service or sentence?

Background: Understanding the meaning of one’s lived experiences improves one’s understanding of what it means to be human, in association with the social, cultural and historical context in which being a human occurs. The authors in this study describe the lived experiences of residents within a chronic care facility including the practitioner and family perspectives.Methods: A qualitative approach was employed with a single-site, descriptive, instrumental case study design. Purposive sampling was utilised to select the chronic facility. Multiple sources of evidence included narratives, semi-structured interviews with staff, residents and family members, and activity profiles of the residents augmented by an ergonomic evaluation of the facility. Content analysis using within-case analysis was implemented.Results: The greatest impact on the quality of the resident’s lived experiences emanates from the physical, organisational and social environments in which they reside. Limited resources, poor staff attitudes and routines that are enforced both on the staff of the facility and the residents appear to reduce optimal functioning within the facility. Furthermore the residents’ intrinsic motivation, presence of enforced idleness, learned helplessness and institutionalisation is often intensified and becomes characteristic of the residents lived experiences.Discussion: The lived experiences of the residents are described according to quality of life indicators that were identified during the study and supported by literature. These include the influence of the physical, social and organizational environments on the residents’ functional status, which comprises physical well-being and emotional well-being and engagement in meaningful occupations including social interaction and relationships with other individuals.Conclusions: Findings of this study may be valuable in understanding and facilitating a positive change in service delivery within chronic care centres.Keywords: chronic care, institutionalisation, lived experiences, residents, occupational deprivatio

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page