Principles of Environmental Remediation in Open and Closed Systems: A Case Study of the Lake Dianchi Drainage Basin

The predominant links between systems science and environmental science are usually made by disciplines such as oceanography, climatology and ecology, but the relationship between systems science and environmental remediation, including contaminated soil and site remediation and solid and wastewater treatment, has not been fully examined. This paper therefore considers the principles of environmental remediation and waste treatment in the context of open and closed systems theory. The characteristics of these systems, to a large degree, dictate the types and parameters of possible interventions, particularly when operating at larger time and distance scales. Three systems are discussed: closed systems, semi-open systems and fully open systems, providing an overview of system characteristics and behavior, along with examples of interventions commonly found in environmental remediation practice. The need for an integrated, interdisciplinary approach to environmental science, technology and engineering when effecting successful open system remediation is also highlighted. A more detailed case study of these systems in the context of Lake Dianchi and its catchment system in Kunming is provided. Located in southern China, the Lake Dianchi drainage basin provides a valuable lesson in socially responsible, long-term environmental remediation, not only because it has been the focus of extensive local and international research and environmental remediation efforts since the 1990s, but because it provides credible evidence of the various types of systems described in this paper

Internal wave pressure, velocity, and energy flux from density perturbations

Determination of energy transport is crucial for understanding the energy budget and fluid circulation in density varying fluids such as the ocean and the atmosphere. However, it is rarely possible to determine the energy flux field $\mathbf{J} = p \mathbf{u}$, which requires simultaneous measurements of the pressure and velocity perturbation fields, $p$ and $\mathbf{u}$. We present a method for obtaining the instantaneous $\mathbf{J}(x,z,t)$ from density perturbations alone: a Green's function-based calculation yields $p$, and $\mathbf{u}$ is obtained by integrating the continuity equation and the incompressibility condition. We validate our method with results from Navier-Stokes simulations: the Green's function method is applied to the density perturbation field from the simulations, and the result for $\mathbf{J}$ is found to agree typically to within $1\%$ with $\mathbf{J}$ computed directly using $p$ and $\mathbf{u}$ from the Navier-Stokes simulation. We also apply the Green's function method to density perturbation data from laboratory schlieren measurements of internal waves in a stratified fluid, and the result for $\mathbf{J}$ agrees to within $6\%$ with results from Navier-Stokes simulations. Our method for determining the instantaneous velocity, pressure, and energy flux fields applies to any system described by a linear approximation of the density perturbation field, e.g., to small amplitude lee waves and propagating vertical modes. The method can be applied using our Matlab graphical user interface EnergyFlux

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion.

Arthrodesis of the sacroiliac joint (SIJ) for surgical treatment of SIJ dysfunction has regained interest among spine specialists. Current techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement; however, image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant placement. In the following cases, we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm® multidimensional surgical imaging with StealthStation® navigation (Medtronic, Inc. Minneapolis, MN). Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site. O-arm® integrated with StealthStation® allowed immediate auto-registration. The skin incision was planned with an image-guidance probe. An image-guided awl, drill and tap were utilized to choose a starting point and trajectory. Threaded titanium cage(s) packed with autograft and/or allograft were then placed. O-arm® image-guidance allowed for implant placement in the SIJ with a small skin incision. However, we could not track the cage depth position with our current system, and in one patient, the SIJ cage had to be revised secondary to the anterior breach of sacrum

Folate-mediated tumor cell targeting of liposome-entrapped doxorubicin in vitro

AbstractReceptors for the vitamin folic acid are frequently overexpressed on epithelial cancer cells. To examine whether this overexpression might be exploited to specifically deliver liposome-encapsulated drug molecules in vitro, folate-targeted liposomes were prepared by incorporating 0.1 mol% of a folate-polyethyleneglycol-distearoylphosphatidylethanolamine (folate-PEG-DSPE) construct into the lipid bilayer, and were loaded with doxorubicin (DOX), an anti-cancer drug. Uptake of folate-PEG-liposomal DOX by KB cells was 45-fold higher than that of non-targeted liposomal DOX, and 1.6-times higher than that of free DOX, while the cytotoxicity was 86 and 2.7-times higher, respectively. Folate-targeting is fully compatible with PEG-coating of the liposomes, since incorporation of 4 mol% PEG2000-DSPE does not reduce the uptake or cytotoxicity of folate-PEG-liposomal DOX. Uptake of folate-PEG-liposomes was inhibited by 1 mM free folic acid but was unaffected by physiological concentrations of folate. In HeLa/W138 co-cultures, folate-PEG-liposomes encapsulating calcein, a fluorescent dye, were found to be almost exclusively internalized by the HeLa cells which overexpress the folate receptors. We suggest that folate targeting constitutes a possible mechanism for improving the specificity of PEG-coated liposomes for cancer cells

Business students\u27 personal branding: An empirical investigation

Personal branding is the process by which an individual actively tries to manage others’ impression of their skills, abilities and experiences (Johnson, 2017). It is the marketing of oneself to society (Lair, Sullivan, & Cheney, 2005; Peters, 1997; Shepherd, 2005). While the current job market is touted as being the best in years, employment opportunities for business aspirants in the U.S. economy changed little from 2017 to 2016 when comparing a United States Department of Labor annual report (“United States Department of Labor,” 2018). This suggests that new business graduates continue to face the harsh reality of a challenging environment in terms of future employment prospects. This accentuates a great need for business schools to arm students with the personal branding skills requisite for today’s competitive employment landscape

On The Nature of Variations in the Measured Star Formation Efficiency of Molecular Clouds

Measurements of the star formation efficiency (SFE) of giant molecular clouds (GMCs) in the Milky Way generally show a large scatter, which could be intrinsic or observational. We use magnetohydrodynamic simulations of GMCs (including feedback) to forward-model the relationship between the true GMC SFE and observational proxies. We show that individual GMCs trace broad ranges of observed SFE throughout collapse, star formation, and disruption. Low measured SFEs (<<1%) are "real" but correspond to early stages, the true "per-freefall" SFE where most stars actually form can be much larger. Very high (>>10%) values are often artificially enhanced by rapid gas dispersal. Simulations including stellar feedback reproduce observed GMC-scale SFEs, but simulations without feedback produce 20x larger SFEs. Radiative feedback dominates among mechanisms simulated. An anticorrelation of SFE with cloud mass is shown to be an observational artifact. We also explore individual dense "clumps" within GMCs and show that (with feedback) their bulk properties agree well with observations. Predicted SFEs within the dense clumps are ~2x larger than observed, possibly indicating physics other than feedback from massive (main sequence) stars is needed to regulate their collapse.Comment: Fixed typo in the arXiv abstrac

Structures of falcipain-2 and falcipain-3 bound to small molecule inhibitors: implications for substrate specificity.

Falcipain-2 and falcipain-3 are critical hemoglobinases of Plasmodium falciparum, the most virulent human malaria parasite. We have determined the 2.9 A crystal structure of falcipain-2 in complex with the epoxysuccinate E64 and the 2.5 A crystal structure of falcipain-3 in complex with the aldehyde leupeptin. These complexes represent the first crystal structures of plasmodial cysteine proteases with small molecule inhibitors and the first reported crystal structure of falcipain-3. Our structural analyses indicate that the relative shape and flexibility of the S2 pocket are affected by a number of discrete amino acid substitutions. The cumulative effect of subtle differences, including those at "gatekeeper" positions, may explain the observed kinetic differences between these two closely related enzymes