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EFFECTS OF A REVERSE OSMOSIS-WATER TREATMENT PLANT BRINY CONCENTRATE DISCHARGED INTO AN OLIGOHALINE ESTUARY.
No full textReverse Osmosis Water Treatment Plants (RO-WTPs) create potable water and a briny concentrate that must be disposed; often it is discharged into nearby surface waters. Currently, there is no published research to examine effects of this discharge on the ambient environment or on resident and transient biota. One established RO-WTP discharge location was used as a model and compared with a control location within the same embayment and the locations of two RO-WTPs pre-construction. These two plants may discharge up to eight times more concentrate into the estuary. A one-year study used acoustic Doppler current profilers; Hydrolab sondes; a YSI meter; and biological and water collections to profile each location. Water movements at all locations were correlated with wind velocity measured at the USCG-EC weather station and the tide cycle at Mann's Harbor marina. Average velocity was lowest at the established RO-WTP and highest at the two proposed locations in fall 2005. Salinity varied significantly (p < 0.001) between the established RO-WTP and one of the proposed locations. From the four locations, we collected 21 species of macroinvertebrates. Location and date were not found to be significant. The effect of briny discharge on two species of macroinvertebrates dissipated beyond 5 m of the diffuser. The macrozooplankton (13 taxa) showed significant differences by date but not location while for the nekton (35 species) showed significant temporal differences (Spearman's Rho = 0.669) and moderate differences by location (Spearman's Rho = 0.237). There was no evidence that the RO-WTP has a significant impact on either the macrozooplankton or nekton collected. Overall, the biotic communities sampled from the four locations are typical for oligohaline to mesohaline estuaries. There were no significant differences in diversity for any biota collected. It is recommended that 1) data collection related to the discharge continue; 2) measurable indicators of biotic integrity from oligohaline to mesohaline environments be developed; and 3) post-construction samples at the two proposed RO-WTPs continue so as to investigate the effects of increased volume of brine on the local surface water as well as the resident and transient biota.
Sex-Specific Abdominal Activation Strategies During Landing
No full textContext: Control of the trunk segment in landing has been implicated as a contributing factor to the higher incidence of anterior cruciate ligament injuries in females than in males. Investigating the sex-specific abdominal activation strategies during landing lends insight into mechanisms contributing to control of the trunk segment. Objective: To examine the abdominal activation strategies used by males and females during a landing task. Design: Mixed-model (between-subjects and within-subjects) design. Setting: Laboratory. Patients or Other Participants: Healthy, recreationally active males (n = 20, age = 23 ± 4.8 years, height = 1.8 ± 0.1 m, mass = 79.6 ± 9.9 kg, body mass index = 24.8 ± 2.7 kg/ m 2) and females (n = 22, age = 20.8 ± 4.8 years, height = 1.7 ± 0.1 m, mass = 64.1 ± 9.2 kg, body mass index = 22.9 ± 2.6 kg/m 2). Intervention(s): Subjects performed 5 double-leg landings from a box height of 60 cm. Main Outcome Measure(s): Male and female activation amplitudes for the rectus abdominis (RA), external oblique (EO), and transversus abdominis and lower fibers of the internal oblique (TrA-IO) muscles during preactivation (150-millisecond interval just before landing) and after impact (150-millisecond interval immediately after ground contact). Results: Males had greater TrA-IO activation than females ( P < .05). Males preferentially activated the TrA-IO muscles relative to the RA and EO, whereas females demonstrated no significant muscle differences. Males and females also differed by phase, with males having more TrA-IO activation than females during the preactivation landing phase ( P < .05) but not during the postimpact phase. The TrA-IO was the only muscle to significantly differ by landing phase, decreasing from preactivation to postimpact ( P < .05). Conclusions: Males used different abdominal muscle activation strategies than females in landing. The efficacy of these muscle activation strategies to control the trunk should be assessed through trunk kinematic and kinetic measures in future studies
Alteration of AKT Activity Increases Chemotherapeutic Drug and Hormonal Resistance in Breast Cancer yet Confers an Achilles Heel by Sensitization to Targeted Therapy
No full textThe PI3K/PTEN/Akt/mTOR pathway plays critical roles in the regulation of cell growth. The effects of this pathway on drug resistance and cellular senescence of breast cancer cells has been a focus of our laboratory. Introduction of activated Akt or mutant PTEN constructs which lack lipid phosphatase [PTEN(G129E)] or lipid and protein phosphatase [PTEN(C124S)] activity increased the resistance of the cells to the chemotherapeutic drug doxorubicin, and the hormonal drug tamoxifen. Activated Akt and PTEN genes also inhibited the induction of senescence after doxorubicin treatment; a phenomenon associated with unrestrained proliferation and tumorigenesis. Interference with the lipid phosphatase domain of PTEN was sufficient to activate Akt/mTOR/p70S6K as MCF-7 cells transfected with the mutant PTEN gene lacking the lipid phosphatase activity [PTEN(G129E)] displayed elevated levels of activated Akt and p70S6K compared to empty vector transfected cells. Cells transfected with mutant PTEN or Akt constructs were hypersensitive to mTOR inhibitors when compared with the parental or empty vector transfected cells. Akt-transfected cells were cultured for over two months in tamoxifen from which tamoxifen and doxorubicin resistant cells were isolated that were >10-fold more resistant to tamoxifen and doxorubicin than the original Akt-transfected cells. These cells had a decreased induction of both activated p53 and total p21Cip1 upon doxorubicin treatment. Furthermore, these cells had an increased inactivation of GSK-3à ² and decreased expression of the estrogen receptor-à ±. In these drug resistant cells, there was an increased activation of ERK which is associated with proliferation. These drug resistant cells were hypersensitive to mTOR inhibitors and also sensitive to MEK inhibitors, indicating that the enhanced p70S6K and ERK expression was relevant to their drug and hormonal resistance. Given that Akt is overexpressed in greater than 50% of breast cancers, our results point to potential therapeutic targets, mTOR and MEK. These studies indicate that activation of the Akt kinase or disruption of the normal activity of the PTEN phosphatase can have dramatic effects on activity of p70S6K and other downstream substrates and thereby altering the therapeutic sensitivity of breast cancer cells. The effects of doxorubicin and tamoxifen on induction of the Raf/MEK/ERK and PI3K/Akt survival pathways were examined in unmodified MCF-7 breast cells. Doxorubicin was a potent inducer of activated ERK and to a lesser extent Akt. Tamoxifen also induced ERK. Thus a consequence of doxorubicin and tamoxifen therapy of breast cancer is the induction of a pro-survival pathway which may contribute to the development of drug resistance. Unmodified MCF-7 cells were also sensitive to MEK and mTOR inhibitors which synergized with both tamoxifen and doxorubicin to induce death. In summary, our results point to the key interactions between the PI3K/PTEN/Akt/mTOR and Raf/MEK/ERK pathways in regulating chemotherapeutic drug resistance/sensitivity in breast cancer and indicate that targeting these pathways may prevent drug and hormonal resistance. Orignally published Advances in Enzyme Regulation, Vol. 48, No. 1, 2008
EXPLORING THE BYSTANDER EFFECT FOLLOWING VERY LOW DOSE RADIATION
No full textBystander effects are defined as the phenomenon in which unirradiated cells respond biologically when their neighbors are irradiated. The exact mechanisms of these cellular responses are still not known, especially in the region considered to be very low dose radiation (<20cGy). Many studies have shown cytokine levels are altered following exposure to radiation and may play a significant role in bringing about bystander responses. A non-tumorigenic (MCF10A) and tumorigenic (A375) cell line were used to determine if chemical factors released from irradiated MCF10A cells will bring about bystander- induced proliferation on naïve (unirradiated) A375 or MCF10A cells using the Irradiated Conditioned Medium (ICM) model. A transfer of conditioned medium 5 hours post- irradiation appeared to bring about a marked bystander response in the naïve A375 cultures which were observed to be maximal between 2 and 6 cGy. This response was not observed at the 1 hour transfer of conditioned medium. Additionally, the data suggest that there is no temporal correlation between the proliferative bystander effects elicited and the levels of IL-6 within the conditioned medium. The data indicate that the MCF10A ICM IL-8 levels were statistically significant only at the 6 cGy dose at 1 hour. Although a significant proliferative bystander effect was observed in A375 cells when exposed to 5 hour MCF10A ICM, the data suggest that both IL-6 and IL-8 do not contribute significantly to this proliferative response.
A Systematic Theory of Emotion
Full text linkA systematic informational framework is used to develop a general theory of emotion. One of the theory's central principles is that each primary form of emotion is sequentially differentiated into at least three distinct components. First, hedonic arousal codes the adaptive significance of primitive stimulation in terms of criteria derived from species' evolutionary history. Second, associative control codes the adaptive significance of memory traces by reproducing the hedonic changes that were paired with previous trace activation. Third, regulation transmits hedonic information to other psychological structures in ways that facilitate future gratification and need fulfillment. Some forms of emotion also contain an exertion feedback component, which codes the successfulness of ongoing exertion. Another of the theory's central principles is that lateral differentiation generate three forms of pleasure (sentia, effectance, and animation) and four forms of distress (exigeance, noxia, frustration, and fear). Research supporting the theory's analysis of sequential differentiation is reviewed in detail, and the motivational function of fear in active avoidance is analyzed as general illustration. The theory's antecedents and metatheoretical assumptions are also briefly discussed
Solving Systems of Equations with Applications to Optimization
Full text linkA research paper focusing on optimization in mathematics and the investigation of iterative methods when applied to the solution of systems equations by Linda C. Collins for the Mathematics department