Search

Reduced freshwater inflow into a coastal marsh can result in environmental stress through episodic hypersalinity. Hydrodynamic models can be used to evaluate salinity-control strategies when freshwater supplies are constrained by climate or increasing urban demands. However, there remain significant scientific, engineering, and technical barriers to correctly modeling salinity transport in such systems. In particular, the numerical instability at the wetting/drying front caused by strong wind stress and steep surface gradient and the inappropriate representation of the complex channels at practical computational scales are unsolved problems. This study documents recent achievements in modeling the time–space evolution of shallow marsh salinity using the Fine Resolution Environmental Hydrodynamic model (Frehd) applied to the Nueces River Delta (Texas, USA). The 2D depth-integrated model is tested across a variety of bathymetric representations derived from high-resolution lidar data to evaluate the effects of grid refinement and a variety of bathymetry processing methods. Novel treatments are proposed and tested to suppress unrealistic velocities and scalar concentrations caused by rapid wetting/drying and strong wind stress. The model results are compared with the field data collected at 12 spatially-distributed locations across the marsh, yielding good model-data agreements for free surface elevation and reasonable agreements for salinity. Analyses of results indicate that the critical difficulty for capturing salinity transport is in correctly representing connectivity effects (both blocking and channel features) at fine scales on the coarse grid without overestimating fluxes. Modeled water surface elevations are relatively robust to poor representation of connectivity whereas the salinity distribution is strongly affected, particularly at key choke points. This study defines a set of future challenges in developing automated methods for evaluating and preserving geometric connectivity at practical model grid resolution. [ABSTRACT FROM AUTHOR]

The authors offer a response to a commentary by F. Parent and colleagues to their article about competency and outcome-based approaches in medical education. They agree with Parent and colleagues that competency-based approaches can improve health professions education and promote a professional expertise better adapted to the new social and societal realities. They also offer an appreciation for Parent and colleagues for engaging them in expanding the competency debate.

Background: Inguinal hernias are the most common operative procedure performed by general surgeons, and tension-free mesh techniques have revolutionized the procedure. While hernia recurrence rates have decreased, chronic postoperative pain has become recognized more widely. New mesh products offer the potential to decrease pain without compromising recurrence rates. Polyester mesh is a softer material than traditional polypropylene and may offer the benefit of causing less postoperative pain and improved quality of life. Methods: Prospective, single-blind, randomized controlled trial involving 78 patients assigned to receive Lichtenstein type repair with either polyester ( n = 39) or polypropylene ( n = 39) mesh. Attempt was made to identify ilioinguinal, iliohypogastric, and genitofemoral nerves intraoperatively and document their handling. Patients were interviewed and examined preoperatively and postoperatively at 2 weeks and 3 months. Inguinal Pain Questionnaire (IPQ) and VAS scores were obtained and analyzed using two sample t test for continuous variables and Chi-square test for categorical variables. Results: VAS scores at 3 months were 0.46 for the polyester group versus 0.56 for the polypropylene group ( P = 0.6727). At 3 months, 82.3% of the polyester and 76.4% of the polypropylene group had VAS = 0 ( P = 0.5486). There was no significant difference between the two groups' VAS scores at 3 months. IPQ did not show any difference between the two groups with the exception of 'catching or pulling' being reported in 34.3% of polyester and 5.7% of polypropylene groups ( P = 0.0028). Conclusions: Polyester mesh does not decrease the amount of chronic pain at 3 months. Outcomes with polyester mesh are comparable to polypropylene mesh for Lichtenstein inguinal hernia repair with regards to postoperative pain and quality of life. The sample size in this study was small and limits the significance of the results. Further studies are needed to find the optimal mesh for inguinal hernia repair. [ABSTRACT FROM AUTHOR]

Recombinant serotype 5 adenovirus (Ad5) vectors lacking E1 expression induce robust immune responses against encoded transgenes in pre-clinical models, but have muted responses in human trials because of widespread pre-existing anti-adenovirus immunity. Attempts to circumvent Ad5-specific immunity by using alternative serotypes or modifying capsid components have not yielded profound clinical improvement. To address this issue, we explored a novel alternative strategy, specifically reducing the expression of structural Ad5 genes by creating E1 and E2b deleted recombinant Ad5 vectors. Our data show that [E1−, E2b−]vectors retaining the Ad5 serotype are potent immunogens in pre-clinical models despite the presence of significant Ad5-specific immunity, in contrast to [E1−] vectors. These pre-clinical studies with E1 and E2b-deleted recombinant Ad5 vectors suggest that anti-Ad immunity will no longer be a limiting factor, and that clinical trials to evaluate their performance are warranted.Cancer Gene Therapy (2009) 16, 673–682; doi:10.1038/cgt.2009.17; published online 20 February 2009 [ABSTRACT FROM AUTHOR]

The loss of cochlear hair cells, or the loss of their capacity to transduce acoustic signals, is believed to be the underlying mechanism in many forms of hearing loss. To develop viral vectors that allow for the introduction of genes directly into the cochleae of adult animals, replication-deficient (E1[sup -], E3[sup -]) and replication-defective (E1[sup -], E3[sup -], pol[sup -]) adenovirus vectors were used to transduce the bacterial β-galactosidase gene into the hair cells of the guinea pig cochlea in vivo. Distortion product otoacoustic emissions, which monitor the functional status of outer hair cells, were measured throughout the viral infection periods to identify hair cell ototoxicity. The results demonstrated that the use of the (E1[sup -], E3[sup -]) adenovirus vectors containing CMV-driven LacZ, compromised cochlear function when gradually introduced into scala tympani via an osmotic pump. However, when (E1[sup -], E3[sup -], pol[sup -] adenoviral vectors containing CMV-driven LacZ were used to transduce cochlear hair cells, there was no loss of cochlear function over the frequency regions tested, and β-galactosidase (βgal) was detected in over 80% of all hair cells. Development of a viral vector that infects cochlear hair cells without virusinduced ototoxic effects is crucial for gene replacement strategies to treat certain forms of inherited deafness and for otoprotective strategies to prevent hair cell losses to treat progressive hearing disorders. Moreover, in vivo (E1[sup -], E3[sup -], pol[sup -]) adenovirus mediated gene-transfer techniques applied to adult guinea pig cochleae may be useful in testing several hypotheses concerning what roles specific genes play in normal cochlear function. [ABSTRACT FROM AUTHOR]

Recent years have seen a growing interest in the use of quantitative parameters for assessing the quality of research carried out at universities. In the UK, university departments are now subject to regular investigations of their research standing. As part of these investigations, a considerable amount of quantitative (as well as qualitative) information is collected from each department. This is made available to the panels appointed to assess research quality in each subject area. One question that has been raised is whether the data can be combined in some way to provide an index which can help guide the panels' deliberations. This question is looked at here via a detailed examination of the returns from four universities for the most recent (1992) research assessment exercise. The results suggest that attempts to derive an algorithm are only likely to be helpful for a limited range of subjects. [ABSTRACT FROM AUTHOR]