343 research outputs found

    System and Process for Providing Auxiliary Information for a Packet-Switched Network of Shared Nodes Using Dedicated Associative Store

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    A system and process for providing auxiliary information about a distributed network of shared nodes, at least a plurality of the nodes being adapted for receiving at least one type of ESP-(associative ephemeral store processing) packet. Available for access at each of the plurality of ESP-adapted nodes is a dedicated associative store wherein a value, if bound to a tag, is only accessible as a bound (tag, value) pair for a short time period, τ. Different types of packets are contemplated for routing through the ESP-capable plurality of nodes such as those arbitrarily identified herein as a ‘first’ and ‘second’ type: each first type packet has at least one field comprising an opcode identifying an instruction, and a tag; each second type packet has an opcode identifying an instruction an LOC field containing an identifier of a location for execution of an operand by the second packet instruction at any one of the ESP-capable plurality of nodes. In another aspect, each of the ESP-capable plurality of nodes has input and output port units and a centralized unit; an associative store may be dedicated to one or more of the port units as well as to the centralized location

    Confidence intervals for a spatially generalized, continuous simulation flood frequency model for Great Britain

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    There is growing interest in the application of "continuous simulation'' conceptual rainfall-runoff models for flood frequency estimation as an adjunct to event-based or statistical design methodology. The approach has advantages that stem from the use of models with continuous water balance accounting. Conceptual rainfall-runoff models usually require calibration, which in turn requires gauged rainfall and flow data. One of the key challenges is therefore to develop ways of generalizing models for use at ungauged sites. Recent work has produced a prototype scheme for achieving this aim in Great Britain for two catchment models by relating model parameters to spatial catchment properties, such as soils, topography, and geology. In this paper we present an analysis of the uncertainty associated with one of the generalized models ( the "probability distributed model'') in terms of confidence intervals for simulations at test sites that are treated as if they were ungauged. This is done by fitting regression relationships between hydrological model parameters and catchment properties so as to estimate the parameters as distribution functions for the ungauged site case. Flood flow outputs are then simulated from the parameter distributions and used to construct approximate confidence intervals. Comparison with gauged data suggests that the generalized model may be tentatively accepted. Uncertainty in the modeled flood flows is often of a similar order to the uncertainty surrounding a more conventional statistical model, in this case a single-site generalized Pareto distribution fitted to the gauged data

    The impact of a standardised intramuscular sedation protocol for acute behavioural disturbance in the emergency department

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    Background: Acute behavioural disturbance (ABD) is an increasing problem in emergency departments. This study aimed to determine the impact of a structured intramuscular (IM) sedation protocol on the duration of ABD in the emergency department. Methods: A historical control study was undertaken comparing 58 patients who required physical restraint and parenteral sedation with the structured IM sedation protocol, to 73 historical controls treated predominantly by intravenous sedation, according to individual clinician preference. The primary outcome was the duration of the ABD defined as the time security staff were required. Secondary outcomes were the requirement for additional sedation, drug related-adverse effects and patient and staff injuries. Results: The median duration of the ABD in patients with the new sedation protocol was 21 minutes (IQR: 15 to 35 minutes; Range: 5 to 78 minutes) compared to a median duration of 30 minutes (IQR: 15 to 50 minutes; Range: 5 to 135 minutes) in the historical controls which was significantly different (p = 0.03). With IM sedation only 27 of 58 patients (47%; 95% CI: 34% to 60%) required further sedation compared to 64 of 73 historical controls (88%; 95%CI: 77% to 94%). There were six (10%) drug-related adverse events with the new IM protocol [oxygen desaturation (5), oxygen desaturation/airway obstruction (1)] compared to 10 (14%) in the historical controls [oxygen desaturation (5), hypoventilation (4) and aspiration (1)]. Injuries to staff occurred with three patients using the new sedation protocol and in seven of the historical controls. Two patients were injured during the new protocol and two of the historical controls. Conclusion: The use of a standardised IM sedation protocol was simple, more effective and as safe for management of ABD compared to predominantly intravenous sedation

    Calmodulin Interacts and Regulates Enzyme Activity of the Mammalian Sperm Phospholipase C

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    Sperm-specific Phospholipase C zeta (PLCζ) is widely considered to be the sole, physiological stimulus responsible for the generation of Ca2+ oscillations that induce egg activation and early embryo development during mammalian fertilization. PLCζ, which is delivered from the fertilizing sperm into the egg cytoplasm, catalyzes the hydrolysis of its membrane-bound phospholipid substrate phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], triggering the cytoplasmic Ca2+ oscillations through the inositol 1,4,5-trisphosphate (InsP3) signaling pathway. Despite the recent advances the detailed regulatory mechanism of PLCζ is still unclear, as binding partners of this protein within the sperm or the fertilizing egg have not yet been identified. Calmodulin (CaM) is a ubiquitous Ca2+ sensor in eukaryotic cells. A previous study has reported that CaM directly interacts and regulates the activity of PLC delta 1 protein, a somatic PLC isoform with structural similarities to sperm PLCζ. Bioinformatics analysis revealed putative CaM-binding sites on PLCζ sequence. In the present study, we have used co-immunoprecipitation analysis and we show that in the presence of Ca2+, human PLCζ directly interacts with CaM. Isothermal titration calorimetry (ITC) experiments were performed to map the interaction. Three different peptides corresponding to disparate sequences within human PLCζ were used and it was shown that PLCζ interacts with CaM via one region of the molecule. In addition, recombinant proteins corresponding to the N- and C-lobe of human CaM were used for ITC experiments, which revealed that CaM interacts with PLCζ in the presence of Ca2+, only through one of its lobe domains. In vitro PIP2 hydrolysis assays revealed that CaM alters PLCζ PIP2 hydrolytic activity at high Ca2+ concentrations and, as suggested by liposome binding assays, this appears to be due to CaM binding to PLCζ affecting proper access of the enzyme active site to its substrate PI(4,5)P2

    Male infertility-linked point mutation disrupts the Ca2+ oscillation-inducing and PIP2 hydrolysis activity of sperm PLCζ

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    A male infertility-linked human PLCζ (phospholipase Cζ) mutation introduced into mouse PLCζ completely abolishes both in vitro PIP2 (phosphatidylinositol 4,5-bisphosphate) hydrolysis activity and the ability to trigger in vivo Ca2+ oscillations in mouse eggs. Wild-type PLCζ initiated a normal pattern of Ca2+ oscillations in eggs in the presence of 10-fold higher mutant PLCζ, suggesting that infertility is not mediated by a dominant-negative mechanism

    Vascular effects of apelin in vivo in man

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    ObjectivesThis study was designed to establish the direct vascular effects of apelin in vivo in man.BackgroundApelin is the endogenous ligand for the previously orphaned G-protein–coupled receptor, APJ. This novel pathway is widely expressed in the cardiovascular system and is emerging as an important mediator of cardiovascular homeostasis. In pre-clinical models, apelin causes venous and arterial vasodilation.MethodsVascular effects of apelin were assessed in 24 healthy volunteers. Dorsal hand vein diameter was measured by the Aellig technique during local intravenous infusions (0.1 to 3 nmol/min) of apelin-36, (Pyr1)apelin-13, and sodium nitroprusside (0.6 nmol/min). Forearm blood flow was measured by venous occlusion plethysmography during intrabrachial infusions of apelin-36 and (Pyr1)apelin-13 (0.1 to 30 nmol/min) and subsequently in the presence or absence of a “nitric oxide clamp” (nitric oxide synthase inhibitor, L-NG-monomethylarginine [8 μmol/min], coinfused with nitric oxide donor, sodium nitroprusside [90 to 900 ng/min]), or a single oral dose of aspirin (600 mg) or matched placebo.ResultsAlthough sodium nitroprusside caused venodilation (p < 0.0001), apelin-36 and (Pyr1)apelin-13 had no effect on dorsal hand vein diameter (p = 0.2). Both apelin isoforms caused reproducible vasodilation in forearm resistance vessels (p < 0.0001). (Pyr1)apelin-13–mediated vasodilation was attenuated by the nitric oxide clamp (p = 0.004) but unaffected by aspirin (p = 0.7).ConclusionsAlthough having no apparent effect on venous tone, apelin causes nitric oxide–dependent arterial vasodilation in vivo in man. The apelin-APJ system merits further clinical investigation to determine its role in cardiovascular homeostasis

    Long Sun-Exposures Influencing High Sub-Cutaneous Synthesis of Vitamin-D3 may be Associated with Exacerbation of Symptoms in Allergic-Asthma.

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    Does excessive sun-exposure, non-use of sunscreen and/or high doses of vitamin-D3 supplements provoke exacerbation of asthma? Clinical examinations, retrospective records-access and questionnaire surveys were distributed to a convenience sample of allergic-asthma patient (n=183). Patients (19-89 years) attending the outpatient respiratory clinics at Maidstone Hospital were enrolled. 90.3% of patients (total IgE levels ≥75 kU/L ; n=103) exposed to direct sunlight of ≥ 15 minutes per day continuously for 6-7 days presented with wheeze (χ2(1) = 7.46; p< 0.05) compared to only 9.7% patients of similar atopy-status, presenting with wheeze if exposed to sunlight of < 15 minutes per day for 6-7 days. 68.9% patients (with IgE levels ≥ 75 kU/L ; n=103), non-users of sunscreen (SPF 30 and above), exposed to direct sunlight of ≥ 15 minutes per day continuously for 6-7 days developed a wheeze, compared to fewer users of sunscreen (9.7%, n=103), exposed to the same duration of sunlight who developed asthma symptoms (p< 0.05). Vitamin-D3 supplementation in asthma-patients with clinical signs of hypovitaminosis-D (n=21), produced symptoms of morning chest-tightness (76.2%), allergic rhinitis (61.9%) and wheeze (100%), 2 weeks after initiation of treatment. Our results advocate direct sunlight exposure < 15 minutes per day and use of sunscreen as a novel approach to preventing atopic-asthma symptoms in allergic-asthma patients.. Activated vitamin-D3 is well-recognised to shift the immune-balance towards Th2 predominance, favouring allergic asthma. These results suggest that limiting subcutaneous synthesis of vitamin-D3 in asthma patients and re-addressing dosage of vitamin-D3 supplementation is necessary may contribute to prevent exacerbation of symptoms

    Defective Interaction of Cam with RyR2 Cam-Binding Pocket Might Contribute to Arrhythmogenic Cardiac Disease

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    Ryanodine receptor 2 (RyR2) is a large transmembrane calcium (Ca2+) release channel that mediates Ca2 release from the sarcoplasmic reticulum to activate cardiac muscle contraction. Calmodulin (CaM) regulation of RyR2 is essential for normal cardiac function. A number of linear fragments of RyR2 have been reported as potential CaM-binding sequences. The sequence 3583-3603aa of human RyR2, which is highly conserved among mammalian isoforms, has been identified as a CaM-binding site in almost all relevant studies and therefore this region is considered as a well-established CaM-binding domain of RyRs. Besides 3583-3603aa region, other RyR2 regions have been also reported as potential CaM-binding sequences. Herein, we used recombinant wild-type CaMprotein and isothermal titration calorimetry (ITC) experiments to screen a number of RyR2-specific synthetic peptides corresponding to the region 4240-4277aa of RyR2, which has been previously proposed as a putative CaM-binding RyR2 region. From all the synthetic peptides screened, a peptide corresponding to 4255-4271aa region of human RyR2 was found to interact with significant affinity with RyR2, in the presence and absence of Ca2+ (Kd values 0.60 and 16.58 μM, respectively). Moreover, investigation of the interaction of four arrhythmogenic CaM mutants (N98I, D132E, D134H and Q136P) with this synthetic peptide, as well as the peptide corresponding to the well-established CaM-binding domain of RyR2 (3583-3603aa), revealed that all mutants show disparate binding properties to these two RyR2 peptides, which have been previously proposed to contribute to a putative intra-subunit CaM-binding pocket. Our findings extend our previous observations suggesting that CaM mutations may trigger arrhythmogenic cardiac disease by altering both intrinsic Ca2+-binding, as well as by dysregulating RyR2-mediated Ca2+ release via defective interaction of CaM with a distinct CaM-binding pocket that multiple RyR2 regions might contribute
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