THE APPLICATION OF PUSH-PULL TESTING TO DEFINE BIOGEOCHEMICAL CONTROLS ON SELENIUM AND NITRATE ATTENUATION IN SATURATED COAL WASTE ROCK

Surface mining of steelmaking coal in the Elk Valley, British Columbia, Canada, has resulted in the release of constituents of interest, such as selenium (Se) and nitrate (NO3-). Oxidation of sulfide minerals in the unsaturated coal waste rock generates water-soluble forms of Se (selenite (Se4+) and selenate (Se6+)). Nitrate, introduced to waste rock through the blasting process, is also water soluble and mobile in the aqueous phase. Limited data suggest attenuation of Se and NO3- via reduction can occur in saturated waste rock, and therefore the placement of waste rock in topographic low areas, such as backfilled pits, could create conditions in which Se and NO3- attenuation would be enhanced. Key factors in the attenuation of these species are the reduction reaction rates and residence time of water in the saturated zone. Water level measurements, slug testing, and groundwater age dating were conducted at the Henretta saturated backfill study area at the Fording River Operation to develop an understanding of the hydraulics of the saturated backfill. Geochemical data collected over approximately 2.5 years were used to examine changes in porewater chemistry over time with respect to individual species, and compare the relationship between species over time (i.e., Se/SO42- and SO42-/NO3-). A method to examine in situ reaction rates (push-pull testing) was developed and tested. Tests were able to identify the consumption of dissolved oxygen (DO) and interpret DO consumption using a first-order reaction equation. Push-pull tests were then conducted at two wells in the study area to determine if Se6+ and/or NO3- can be attenuated over a 3-day test period. Additional information on the reduction potential of the study area was gathered from Se speciation analysis, NO3- isotopes, and dissolved organic carbon concentrations. Slug testing demonstrated that the waste rock is highly permeable (hydraulic conductivity on the order of 10-4 m/s), and tritium-helium age dating showed that water flow within the saturated fill is rapid. Although changes occurred in porewater geochemistry over time, the relative concentrations of SO42- and NO3- remained stable. On the other hand, the relationship between Se and SO42- varied over time, suggesting differences in the availability or attenuation of Se relative to SO42-. Results of push-pull testing, Se speciation, and NO3- isotope analyses indicate no observable Se or NO3- reduction occurred at the site over the period of testing (i.e., 3 d)

Modern Eolian Processes on the Southern High Plains

Eolian processes have substantially modified the landscape on the Southern High Plains within historic times. The maximum inferred rate of deflation was 18.9 mm/year at a site in Bailey County, Texas, a region of loose, sandy soils and frequent, seasonal dust storms. At least locally, agricultural practices have accelerated natural rates of erosion and deposition by winds. An extensive cover of windblown sand and silt mantles the gently sloping surface of the Southern High Plains. Eolian deflation and deposition are among the dominant geomorphic processes affecting this region throughout most of the Holocene and Pleistocene time. Historically, human activities have heightened the importance of wind action by disrupting the natural vegetative cover, thereby exposing the unconsolidated sediments. Agriculture, particularly dry-land cultivation, has been the principal form of land use in the area since the early 1900s or before (Webb, 1931). The effects of tilling practices on deflation are shown in Figure 1. The cultivated field on the right (east) is approximately 0.8 m lower than the range site on the left (west). This long, narrow field was cleared and probably brought into cultivation in the 1920s (C. D. Tunnell, personal communication, 1983). Its furrows run from north to south, along the field's long axis. The orientation of these furrows tends to maximize local deflation, as the furrows are parallel to the dominant winds. During the winter and early spring, some of the strongest winds are from the north, whereas the prevailing wind direction is southerly at other times of the year (Bomar, 1983). Other factors that enhance the erosional impact of the wind include antecedent dry conditions and frost heaving. Both are seasonal effects that increase the soil's susceptibility to removal during the frequent spring dust storms. After becoming entrained, soil aggregates from this field and others like it are transported from their source and redeposited as a broad sheet of eolian sediment.Bureau of Economic Geolog

Type II Kinase Inhibitors Show an Unexpected Inhibition Mode against Parkinson’s Disease-Linked LRRK2 Mutant G2019S

A number of well-known type II inhibitors (ATP-noncompetitive) that bind kinases in their DFG-out conformation were tested against wild-type LRRK2 and the most common Parkinson’s disease-linked mutation, G2019S. We found that traditional type II inhibitors exhibit surprising variability in their inhibition mechanism between the wild type (WT) and the G2019S mutant of LRRK2. The type II kinase inhibitors were found to work in an ATP-competitive fashion against the G2019S mutant, whereas they appear to follow the expected noncompetitive mechanism against WT. Because the G2019S mutation lies in the DXG motif (DYG in LRRK2 but DFG in most other kinases) of the activation loop, we explored the structural consequence of the mutation on loop dynamics using an enhanced sampling method called metadynamics. The simulations suggest that the G2019S mutation stabilizes the DYG-in state of LRRK2 through a series of hydrogen bonds, leading to an increase in the conformational barrier between the active and inactive forms of the enzyme and a relative stabilization of the active form. The conformational bias toward the active form of LRRK2 mutants has two primary consequences. (1) The mutant enzyme becomes hyperactive, a known contributor to the Parkinsonian phenotype, as a consequence of being “locked” into the activated state, and (2) the mutation creates an unusual allosteric pocket that can bind type II inhibitors but in an ATP-competitive fashion. Our results suggest that developing type II inhibitors, which are generally considered superior to type I inhibitors because of desirable selectivity profiles, might be especially challenging for the G2019S LRRK2 mutant

Hmong Adults Self-Rated Oral Health: A Pilot Study

Since 1975, the Hmong refugee population in the U.S. has increased over 200%. However, little is known about their dental needs or self-rated oral health (SROH). The study aims were to: (1) describe the SROH, self-rated general health (SRGH), and use of dental/physician services; and (2) identify the factors associated with SROH among Hmong adults. A cross-sectional study design with locating sampling methodology was used. Oral health questionnaire was administered to assess SROH and SRGH, past dental and physician visits, and language preference. One hundred twenty adults aged 18–50+ were recruited and 118 had useable information. Of these, 49% rated their oral health as poor/fair and 30% rated their general health as poor/fair. Thirty-nine percent reported that they did not have a regular source of dental care, 46% rated their access to dental care as poor/fair, 43% visited a dentist and 66% visited a physician within the past 12 months. Bivariate analyses demonstrated that access to dental care, past dental visits, age and SRGH were significantly associated with SROH (P \u3c 0.05). Multivariate analyses demonstrated a strong association between access to dental care and good/excellent SROH. About half of Hmong adults rated their oral health and access to dental care as poor. Dental insurance, access to dental care, past preventive dental/physician visits and SRGH were associated with SROH

Enzymatic Characterization of ER Stress-Dependent Kinase, PERK, and Development of a High-Throughput Assay for Identification of PERK Inhibitors

PERK is serine/threonine kinase localized to the endoplasmic reticulum (ER) membrane. PERK is activated and contributes to cell survival in response to a variety of physiological stresses that affect protein quality control in the ER, such as hypoxia, glucose depravation, increased lipid biosynthesis, and increased protein translation. Pro-survival functions of PERK are triggered by such stresses, suggesting that development of small-molecule inhibitors of PERK may be efficacious in a variety of disease scenarios. Hence, we have conducted a detailed enzymatic characterization of the PERK kinase to develop a high-throughput-screening assay (HTS) that will permit the identification of small-molecule PERK inhibitors. In addition to establishing the Km of PERK for both its primary substrate, eIF2?, and for adenosine triphosphate, further mechanistic studies revealed that PERK targets its substrate via either a random/steady-state ordered mechanism. For HTS, we developed a time-resolved fluorescence resonance energy transfer–based assay that yielded a robust Z? factor and percent coefficient of variation value, enabling the successful screening of 79,552 compounds. This approach yielded one compound that exhibited good in vitro and cellular activity. These results demonstrate the validity of this screen and represent starting points for drug discovery efforts

A prospective comparison of three argatroban treatment regimens during hemodialysis in end-stage renal disease

A prospective comparison of three argatroban treatment regimens during hemodialysis in end-stage renal disease.BackgroundWe prospectively evaluated 3 treatment regimens of argatroban, a direct thrombin inhibitor, for providing adequate, safe anticoagulation in patients with end-stage renal disease (ESRD) during hemodialysis.MethodsIn this randomized, 3-way crossover study, ESRD patients underwent hemodialysis sessions of 3- or 4-hour duration using high-flux membranes and each of 3 argatroban treatment regimens (A: 250-μg/kg bolus, with an additional 250-μg/kg bolus allowed; B: 250-μg/kg bolus followed by 2-μg/kg/min infusion; C: steady-state, 2-μg/kg/min infusion initiated 4 hours before dialysis). Pharmacodynamic effects including activated clotting times (ACTs); hemodialysis efficacy including single-pool Kt/V, urea reduction ratio (URR), and circuit flow; and safety through a 3-day follow-up were monitored. Argatroban pharmacokinetic parameters including dialytic clearance were evaluated during regimen C.ResultsThirteen patients completed 38 hemodialysis sessions (1 patient withdrew consent after 2 sessions). Mean ± SD ACTs increased from 131 ± 14 seconds at baseline to 153 ± 24, 200 ± 30, and 197 ± 33 seconds, respectively, after 60 minutes of hemodialysis using regimens A, B, and C. Across regimens, mean Kt/Vs (1.5–1.6) and URRs (70%-73%) were comparable. No dialyzer was changed; 1 session was shortened 15 minutes because of circuit clot formation. Systemic argatroban clearance increased ∼20% during hemodialysis, without clinically significantly affecting ACTs. Upon argatroban discontinuation, ACTs and plasma argatroban decreased concurrently (elimination half-life, 35 ± 6 min). No thrombosis, bleeding, serious adverse events, or clinically significant changes in vital signs or routine laboratory measures occurred.ConclusionArgatroban, administered by each treatment regimen, provides safe, adequate anticoagulation to enable successful hemodialysis in ESRD patients. Argatroban dialytic clearance by high-flux membranes is clinically insignificant

Sensor technologies for quality control in engineered tissue manufacturing

The use of engineered cells, tissues, and organs has the opportunity to change the way injuries and diseases are treated. Commercialization of these groundbreaking technologies has been limited in part by the complex and costly nature of their manufacture. Process-related variability and even small changes in the manufacturing process of a living product will impact its quality. Without real-time integrated detection, the magnitude and mechanism of that impact are largely unknown. Real-time and non-destructive sensor technologies are key for in-process insight and ensuring a consistent product throughout commercial scale-up and/or scale-out. The application of a measurement technology into a manufacturing process requires cell and tissue developers to understand the best way to apply a sensor to their process, and for sensor manufacturers to understand the design requirements and end-user needs. Furthermore, sensors to monitor component cells’ health and phenotype need to be compatible with novel integrated and automated manufacturing equipment. This review summarizes commercially relevant sensor technologies that can detect meaningful quality attributes during the manufacturing of regenerative medicine products, the gaps within each technology, and sensor considerations for manufacturing

Structure–activity relationship study of beta-carboline derivatives as haspin kinase inhibitors

Haspin is a serine/threonine kinase that phosphorylates Thr-3 of histone H3 in mitosis that has emerged as a possible cancer therapeutic target. High throughput screening of approximately 140,000 compounds identified the beta-carbolines harmine and harmol as moderately potent haspin kinase inhibitors. Based on information obtained from a structure–activity relationship study previously conducted for an acridine series of haspin inhibitors in conjunction with in silico docking using a recently disclosed crystal structure of the kinase, harmine analogs were designed that resulted in significantly increased haspin kinase inhibitory potency. The harmine derivatives also demonstrated less activity towards DYRK2 compared to the acridine series. In vitro mouse liver microsome stability and kinase profiling of a representative member of the harmine series (42, LDN-211898) are also presented