Primary weathering rates, water transit times, and concentration-discharge relations:a theoretical analysis for the critical zone

The permeability architecture of the critical zone exerts a major influence on the hydrogeochemistry of the critical zone. Water flow path dynamics drive the spatiotemporal pattern of geochemical evolution and resulting streamflow concentration-discharge (C-Q) relation, but these flow paths are complex and difficult to map quantitatively. Here we couple a new integrated flow and particle tracking transport model with a general reversible Transition State Theory style dissolution rate law to explore theoretically how C-Q relations and concentration in the critical zone respond to decline in saturated hydraulic conductivity (K-s) with soil depth. We do this for a range of flow rates and mineral reaction kinetics. Our results show that for minerals with a high ratio of equilibrium concentration (C-eq) to intrinsic weathering rate (R-max), vertical heterogeneity in K-s enhances the gradient of weathering-derived solute concentration in the critical zone and strengthens the inverse stream C-Q relation. As C-eq/R-max decreases, the spatial distribution of concentration in the critical zone becomes more uniform for a wide range of flow rates, and stream C-Q relation approaches chemostatic behavior, regardless of the degree of vertical heterogeneity in K-s. These findings suggest that the transport-controlled mechanisms in the hillslope can lead to chemostatic C-Q relations in the stream while the hillslope surface reaction-controlled mechanisms are associated with an inverse stream C-Q relation. In addition, as C-eq/R-max decreases, the concentration in the critical zone and stream become less dependent on groundwater age (or transit time)

Spontaneous purinergic neurotransmission in the mouse urinary bladder

Spontaneous purinergic neurotransmission was characterized in the mouse urinary bladder, a model for the pathological or ageing human bladder. Intracellular electrophysiological recording from smooth muscle cells of the detrusor muscle revealed spontaneous depolarizations, distinguishable from spontaneous action potentials (sAPs) by their amplitude (< 40 mV) and insensitivity to the L-type Ca(2+) channel blocker nifedipine (1 μm) (100 ± 29%). Spontaneous depolarizations were abolished by the P2X(1) receptor antagonist NF449 (10 μm) (frequency 8.5 ± 8.5% of controls), insensitive to the muscarinic acetylcholine receptor antagonist atropine (1 μm) (103.4 ± 3.0%), and became more frequent in latrotoxin (LTX; 1 nm) (438 ± 95%), suggesting that they are spontaneous excitatory junction potentials (sEJPs). Such sEJPs were correlated, in amplitude and timing, with focal Ca(2+) transients in smooth muscle cells (measured using confocal microscopy), suggesting a common origin: ATP binding to P2X(1) receptors. sAPs were abolished by NF449, insensitive to atropine (126 ± 39%) and increased in frequency by LTX (930 ± 450%) suggesting a neurogenic, purinergic origin, in common with sEJPs. By comparing the kinetics of sAPs and sEJPs, we demonstrated that sAPs occur when sufficient cation influx through P2X(1) receptors triggers L-type Ca(2+) channels; the first peak of the differentiated rising phase of depolarizations – attributed to the influx of cations through the P2X(1) receptor – is of larger amplitude for sAPs (2248 mV s(−1)) than sEJPs (439 mV s(−1)). Surprisingly, sAPs in the mouse urinary bladder, unlike those from other species, are triggered by stochastic ATP release from parasympathetic nerve terminals rather than being myogenic

Gender Monstrosity

Deadgirl (2008) is based around a group of male teens discovering and claiming ownership of a bound female zombie, using her as a sex slave. This narrative premise raises numerous tensions that are particularly amplified by using a zombie as the film’s central victim. The Deadgirl is sexually passive yet monstrous, reifying the horrors associated with the female body in patriarchal discourses. She is objectified on the basis of her gender, and this has led many reviewers to dismiss the film as misogynistic Torture Porn. However, the conditions under which masculinity is formed here – where adolescent males become "men" by enacting sexual violence – are as problematic as the specter of the female zombie. Deadgirl is clearly horrific and provocative: in this article I seek to probe implications arising from the film’s gender conflicts

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Phase 2, double-blind, placebo-controlled, dose-response trial of intravenous adenosine for perioperative analgesia

Adenosine regulates pain transmission by actions at spinal, supraspinal, and peripheral sites. A few studies have suggested that administration of adenosine might be associated with anesthetic- and analgesic-sparing effects. The primary aim of this multicenter study was to determine the dose-response profile of adenosine with respect to perioperative analgesia. Women undergoing major gynecologic surgery were enrolled. Subjects were randomly assigned to receive one of four doses of adenosine (25, 50, 100, or 200 microg x kg x min) or matching placebo. A dose-escalation cohort approach was followed. Study drug administration was started in the operating room at the time of skin incision and discontinued at the end of surgery. The anesthetic technique was standardized. Postoperative analgesia was provided with a standardized morphine patient-controlled analgesia system. Data were collected in the hospital and after discharge daily through postoperative day 7. A total of 166 subjects received treatment with study drug: 125 received adenosine and 41 received placebo. Except for height, there were no differences between treatment groups with respect to demographic or baseline characteristics. Cumulative opioid use during the initial 24-h period after extubation was not significantly different between treatment groups. There were also no differences between treatment groups with respect to cumulative anesthetic use, intraoperative opioid requirements, pain scores, sedation, time to readiness for discharge from the postanesthesia care unit, time to readiness for discharge from the hospital, opioid-related symptom distress scores, patient satisfaction with pain control, and occurrence of adverse events. There were no differences between placebo and adenosine with respect to efficacy and safety for perioperative analgesia