Rural zoning in Missouri : basis, procedure, and effect

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Thermomechanical and bithermal fatigue behavior of cast B1900 + Hf and wrought Haynes 188

High temperature thermomechanical and bithermal fatigue behavior was investigated for two superalloys: cast nickel-base B1900+Hf and wrought cobalt-base Haynes 188. Experimental results were generated to support development of an advanced thermal fatigue life prediction method. Strain controlled thermomechanical and load-controlled, strain-limited, bithermal fatigue tests were used to determine the fatigue crack initiation and cyclic stress-strain response characteristics of superalloys. Bithermal temperatures of 483 and 871 C were used for B1900+Hf, and 316 and 760 C for Haynes 188. Thermomechanical fatigue tests were conducted by using maximum and minimum temperatures corresponding to those for the bithermal experiments. Lives cover the range from about 10 to 3000 cycles to failure. Isothermal fatigue results obtained previously are also discussed

Long-term yogurt consumption and risk of incident hypertension in adults

The Nurses' Health Study and Health Professionals Follow-up Study cohorts are supported by grants UM1 CA186107, UM1 CA176726, and UM1 CA167552 from the National Institutes of Health. The current analyses were supported by small grants from the National Dairy Council, the General Mills Bell Institute for Health and Nutrition, and the Boston Nutrition and Obesity Research Center. The Boston Nutrition Obesity Research Center is administratively based at Boston Medical Center and is funded by the National Institutes of Health (NIH/NIDDK) grant P30DK046200. (UM1 CA186107 - National Institutes of Health; UM1 CA176726 - National Institutes of Health; UM1 CA167552 - National Institutes of Health; small grants from the National Dairy Council; General Mills Bell Institute for Health and Nutrition; Boston Nutrition and Obesity Research Center; P30DK046200 - National Institutes of Health (NIH/NIDDK))Accepted manuscrip

KIR channel activation contributes to onset and steady-state exercise hyperemia in humans

We tested the hypothesis that activation of inwardly rectifying potassium (KIR) channels and Na+-K+-ATPase, two pathways that lead to hyperpolarization of vascular cells, contributes to both the onset and steady-state hyperemic response to exercise. We also determined whether after inhibiting these pathways nitric oxide (NO) and prostaglandins (PGs) are involved in the hyperemic response. Forearm blood flow (FBF; Doppler ultrasound) was determined during rhythmic handgrip exercise at 10% maximal voluntary contraction for 5 min in the following conditions: control [saline; trial 1 (T1)]; with combined inhibition of KIR channels and Na+-K+-ATPase alone [via barium chloride (BaCl2) and ouabain, respectively; trial 2(T2)]; and with additional combined nitric oxide synthase (NG-monomethyl-l-arginine) and cyclooxygenase inhibition [ketorolac; trial 3 (T3)]. In T2, the total hyperemic responses were attenuated ∼50% from control (P \u3c 0.05) at exercise onset, and there was minimal further effect in T3 (protocol 1; n= 11). In protocol 2 (n = 8), steady-state FBF was significantly reduced during T2 vs. T1 (133 ± 15 vs. 167 ± 17 ml/min; Δ from control: −20 ± 3%; P \u3c 0.05) and further reduced during T3 (120 ± 15 ml/min; −29 ± 3%; P \u3c 0.05 vs. T2). In protocol 3 (n = 8), BaCl2 alone reduced FBF during onset (∼50%) and steady-state exercise (∼30%) as observed in protocols 1 and 2, respectively, and addition of ouabain had no further impact. Our data implicate activation of KIR channels as a novel contributing pathway to exercise hyperemia in humans

High-power picosecond fiber source for coherent Raman microscopy

We report a high-power picosecond fiber pump laser system for coherent Raman microscopy (CRM). The fiber laser system generates 3.5ps pulses with 6W average power at 1030nm. Frequency doubling yields more than 2W of green light, which can be used to pump an optical parametric oscillator to produce the pump and the Stokes beams for CRM. Detailed performance data on the laser and the various wavelength conversion steps are discussed, together with representative CRM images of fresh animal tissue obtained with the new source.Chemistry and Chemical Biolog

Photoswitchable fatty acids enable optical control of TRPV1

Fatty acids (FAs) are not only essential components of cellular energy storage and structure, but play crucial roles in signalling. Here we present a toolkit of photoswitchable FA analogues (FAAzos) that incorporate an azobenzene photoswitch along the FA chain. By modifying the FAAzos to resemble capsaicin, we prepare a series of photolipids targeting the Vanilloid Receptor 1 (TRPV1),a non-selective cation channel known for its role in nociception. Several azo-capsaicin derivatives (AzCAs) emerge as photoswitchable agonists of TRPV1 that are relatively inactive in the dark and become active on irradiation with ultraviolet-A light. This effect can be rapidly reversed by irradiation with blue light and permits the robust optical control of dorsal root ganglion neurons and C-fibre nociceptors with precision timing and kinetics not available with any other technique. More generally, we expect that photolipids will find many applications in controlling biological pathways that rely on protein-lipid interactions

Aerothermal Design of a Common Probe for Multiple Planetary Destinations

Estimate the mass of the Thermal Protection System (TPS) for a single design construct of an atmospheric entry probe with a rigid aeroshell, which could be used at five destinations, i.e. Venus, Saturn, Uranus, Neptune, and perhaps, Jupiter. The entry mass of the probe is 400 kg with a ballistic coefficient of 216 kg/m2. Process: The 3DoF trajectory simulation program Traj, coupled with the TPS response program FIAT was used for simulation and design. The assumed atmospheric models were VIRA (Venus-GRAM) for Venus, the Julianne Moses' model for Saturn, a NASA Ames engineering model for Uranus, Neptune-GRAM for Neptune, and Galileo Probe (Al Seiff's) result for Jupiter

Impaired Peripheral Vasodilation during Graded Systemic Hypoxia in Healthy Older Adults: Role of the Sympathoadrenal System

Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound) and vascular conductance (FVC) was calculated in 12 young (24±1 yrs) and 10 older (63±2 yrs) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade of β-receptors (propranolol), and combined blockade of α+β receptors (phentolamine + propranolol). Under control conditions, older adults exhibited impaired vasodilation to hypoxia compared with young at all levels of hypoxia (peak ΔFVC at 80% SpO2 = 4±6 vs. 35±8%; P\u3c0.01). During β-blockade, older adults actively constricted at 85 and 80% SpO2 (peak ΔFVC at 80% SpO2= -13±6%; P\u3c0.05 vs. control) whereas the response in the young was not significantly impacted (peak ΔFVC = 28±8%). Combined α+β blockade increased the dilatory response to hypoxia in young adults, however older adults failed to significantly vasodilate (peak ΔFVC at 80% SpO2= 12±11% vs. 58±11%; P\u3c0.05). Our findings indicate that peripheral vasodilation to graded systemic hypoxia is significantly impaired in older adults which cannot be fully explained by altered sympathoadrenal control of vascular tone. Thus, the impairment in hypoxic vasodilation is likely due to attenuated local vasodilatory and/or augmented vasoconstrictor signaling with age

Reactive Hyperemia Occurs Via Activation of Inwardly Rectifying Potassium Channels and Na+/K+-ATPase in Humans

Rationale: Reactive hyperemia (RH) in the forearm circulation is an important marker of cardiovascular health, yet the underlying vasodilator signaling pathways are controversial and thus remain unclear. Objective: We hypothesized that RH occurs via activation of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase and is largely independent of the combined production of the endothelial autocoids nitric oxide (NO) and prostaglandins in young healthy humans. Methods and Results: In 24 (23±1 years) subjects, we performed RH trials by measuring forearm blood flow (FBF; venous occlusion plethysmography) after 5 minutes of arterial occlusion. In protocol 1, we studied 2 groups of 8 subjects and assessed RH in the following conditions. For group 1, we studied control (saline), KIR channel inhibition (BaCl2), combined inhibition of KIR channels and Na+/K+-ATPase (BaCl2 and ouabain, respectively), and combined inhibition of KIR channels, Na+/K+-ATPase, NO, and prostaglandins (BaCl2, ouabain, L-NMMA [NG-monomethyl-L-arginine] and ketorolac, respectively). Group 2 received ouabain rather than BaCl2 in the second trial. In protocol 2 (n=8), the following 3 RH trials were performed: control; L-NMMA plus ketorolac; and L-NMMA plus ketorolac plus BaCl2 plus ouabain. All infusions were intra-arterial (brachial). Compared with control, BaCl2 significantly reduced peak FBF (−50±6%; P2 (−61±3%) and ouabain (−44±12%) alone, and this effect was enhanced when combined (−87±4%), nearly abolishing RH. L-NMMA plus ketorolac did not impact total RH FBF before or after administration of BaCl2 plus ouabain. Conclusions: Activation of KIR channels is the primary determinant of peak RH, whereas activation of both KIR channels and Na+/K+-ATPase explains nearly all of the total (AUC) RH in humans

Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions—an in situ randomised clinical study

ObjectiveThe objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w/w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation.Materials and methodsSubjects (n = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU).ResultsAfter 4 h, the results for RER, ARR and EFU were in the order PC > TD = RD > NC with PC > TD = RD = NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated.ConclusionsIn this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice.Clinical relevanceAddition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties