Use of a Mendelian randomization approach to assess the causal relation of gamma-Glutamyltransferase with blood pressure and serum insulin levels.

Elevated levels of γ-glutamyltransferase (GGT) have been associated with elevated blood pressure (BP) and diabetes. However, the causality of these relations has not been addressed. The authors performed a cross-sectional analysis (2003-2006) among 4,360 participants from the population-based Cohorte Lausannoise (CoLaus) Study (Lausanne, Switzerland). The rs2017869 variant of the γ-glutamyltransferase 1 (GGT1) gene, which explained 1.6% of the variance in GGT levels, was used as an instrument for Mendelian randomization (MR). Sex-specific GGT quartiles were strongly associated with both systolic and diastolic BP (all P's < 0.0001). After multivariable adjustment, these relations were attenuated but remained significant. Using MR, the authors observed no positive association of GGT with BP (systolic: β -5.68, 95% confidence interval (CI): -11.51, 0.16 (P = 0.06); diastolic: β = -2.24, 95% CI: -5.98, 1.49 (P = 0.24)). The association of GGT with insulin was also attenuated after multivariable adjustment but persisted in the fully adjusted model (β = 0.07, 95% CI: 0.04, 0.09; P < 0.0001). Using MR, the authors also observed a positive association of GGT with insulin (β = 0.19, 95% CI: 0.01, 0.37; P = 0.04). In conclusion, the authors found evidence for a direct causal relation of GGT with fasting insulin but not with BP.

Assessing the impact of high-pressure processing on selected physical and biochemical attributes of white cabbage (Brassica oleracea L. var. capitata alba)

The aim of this study was to investigate the effect of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on key physical and chemical characteristics of white cabbage (Brassica oleracea L. var. capitata alba). Thermal treatment (blanching) was also investigated and compared with high-pressure processing (HPP). HPP at 400 MPa and 20–40 °C caused significantly larger colour changes compared to any other pressure or thermal treatment. All pressure treatments induced a softening effect, whereas blanching did not significantly alter texture. Both blanching and pressure treatments resulted in a reduction in the levels of ascorbic acid, effect that was less pronounced for blanching and HPP at 600 MPa and 20–40 °C. HPP at 600 MPa resulted in significantly higher total phenol content, total antioxidant capacity and total isothiocyanate content compared to blanching. In summary, the colour and texture of white cabbage were better preserved by blanching. However, HPP at 600 MPa resulted in significantly higher levels of phytochemical compounds. The results of this study suggest that HPP may represent an attractive technology to process vegetable-based food products that better maintains important aspects related to the content of health-promoting compounds. This may be of particular relevance to the food industry sector involved in the development of convenient novel food products with excellent functional properties

High pressure processing of swede (Brassica napus): Impact on quality properties

The effects of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on the physical and nutritional properties of swede roots (Brassica napus var. napobrassica) were assessed. Changes induced by high pressure processing (HPP) on the original properties of swede samples were compared with those produced by thermal treatment (blanching). All studied treatments altered the physical properties of swede, resulting in a loss of hardness and water binding capacity. The strongest alteration of texture was observed after HPP at 400 MPa, while 600 MPa was the treatment that better preserved the texture properties of swede. Blanching caused less total colour changes (ΔE) than HPP. Antioxidant properties of swede were measured as total antioxidant capacity, ascorbic acid and total phenol content. All treatments caused a loss of antioxidant capacity, which was less pronounced after HPP at 600 MPa and 20 °C and blanching. Four glucosinolates were detected in swede roots, glucoraphanin, progoitrin, glucobrassicanapin and glucobrassicin. Glucobrassicanapin and glucobrassicin contents were reduced with all studied treatments. Progoitrin content was not affected by blanching and HPP at 200 MPa. HPP at higher pressure levels (400 and 600 MPa), though, induced an increase of progoitrin levels. The results indicated that blanching and HPP at 600 MPa and 20 °C were the treatments that better preserved the original quality properties of swede.

Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure.

Numerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,607), we identified at genome-wide significance (P = 2.7 × 10(-8) to P = 2.3 × 10(-13)) four new PP loci (at 4q12 near CHIC2, 7q22.3 near PIK3CG, 8q24.12 in NOV and 11q24.3 near ADAMTS8), two new MAP loci (3p21.31 in MAP4 and 10q25.3 near ADRB1) and one locus associated with both of these traits (2q24.3 near FIGN) that has also recently been associated with SBP in east Asians. For three of the new PP loci, the estimated effect for SBP was opposite of that for DBP, in contrast to the majority of common SBP- and DBP-associated variants, which show concordant effects on both traits. These findings suggest new genetic pathways underlying blood pressure variation, some of which may differentially influence SBP and DBP.

Direct numerical simulations of interface dynamics to link capillary pressure and total surface energy

The flow of two immiscible fluids through a porous medium depends on the complex interplay between gravity, capillarity, and viscous forces. The interaction between these forces and the geometry of the medium gives rise to a variety of complex flow regimes that are difficult to describe using continuum models. Although a number of pore-scale models have been employed, a careful investigation of the macroscopic effects of pore-scale processes requires methods based on conservation principles in order to reduce the number of modeling assumptions. In this work we perform direct numerical simulations of drainage by solving Navier-Stokes equations in the pore space and employing the Volume Of Fluid (VOF) method to track the evolution of the fluid-fluid interface. After demonstrating that the method is able to deal with large viscosity contrasts and model the transition from stable flow to viscous fingering, we focus on the macroscopic capillary pressure and we compare different definitions of this quantity under quasi-static and dynamic conditions. We show that the difference between the intrinsic phase-average pressures, which is commonly used as definition of Darcy-scale capillary pressure, is subject to several limitations and it is not accurate in presence of viscous effects or trapping. In contrast, a definition based on the variation of the total surface energy provides an accurate estimate of the macroscopic capillary pressure. This definition, which links the capillary pressure to its physical origin, allows a better separation of viscous effects and does not depend on the presence of trapped fluid clusters.

Pressure Relief and Other Joint Rehabilitation Techniques, HR-1042, 1987

A study of four major concrete pavement joint rehabilitation techniques has been conducted, including: pressure relief joints, full-depth repairs, partial-depth repairs and joint resealing. The products of this research include the following for each technique: a summary of published research, detailed documentation of the design and performance of the 36 projects, conclusions and recommendations of the state highway engineers panel, "Design and Construction Guidelines" and "Guide Specifications." The latter two products are prepared for use by state highway agencies. The results of this study are based upon a review of literature, extensive field surveys and analysis of 36 rehabilitation projects, and the experience of an expert panel of state highway engineers.

Plastic Air Content versus Hardened Air Content by High Pressure Air Meter, MLR-99-03, 2001

Plastic air content is typically tested by the pressure method, ASTM C138. Loss of air content through the paver has been shown to exceed 2 percent at times. Research has shown that early deterioration of pavements in Iowa may be directly or indirectly related to low or inadequate air content. Hardened air content is typically checked using the linear traverse method, ASTM C457. The linear traverse method is very time consuming and could not be used on a production scale. A quick and effective method of testing in place air content is needed. Research has shown a high degree of correlation with the high-pressure method of determining air content of hardened concrete versus plastic air content in laboratory conditions. This research indicated that air contents are more variable when comparing core results to plastic air content, although the overall average for the air content was comparable. Perhaps, the location of the plastic air content test, obtained from construction records, versus location of the cores was not as accurate as needed.

High pressure induced changes in beef muscle proteome: correlation with quality parameters

The relationship between pressure induced changes on individual proteins and selected quality parameters in bovine longissimus thoracis et lumborum (LTL) muscle was studied. Pressures ranging from 200 to 600 MPa at 20 °C were used. High pressure processing (HPP) at pressures above 200 MPa induced strong modifications of protein solubility, meat colour and water holding capacity (WHC). The protein profiles of non-treated and pressure treated meat were observed using two dimensional electrophoresis. Proteins showing significant differences in abundance among treatments were identified by mass spectrometry. Pressure levels above 200 MPa strongly modified bovine LTL proteome with main effects being insolubilisation of sarcoplasmic proteins and solubilisation of myofibrillar proteins. Sarcoplasmic proteins were more susceptible to HPP effects than myofibrillar. Individual protein changes were significantly correlated with protein solubility, L*, b* and WHC, providing further insights into the mechanistic processes underlying HPP influence on quality and providing the basis for the future development of protein markers to assess the quality of processed meats.

Increased salt sensitivity of ambulatory blood pressure in women with a history of severe preeclampsia.

Cardiovascular diseases are the principal cause of death in women in developed countries and are importantly promoted by hypertension. The salt sensitivity of blood pressure (BP) is considered as an important cardiovascular risk factor at any BP level. Preeclampsia is a hypertensive disorder of pregnancy that arises as a risk factor for cardiovascular diseases. This study measured the salt sensitivity of BP in women with a severe preeclampsia compared with women with no pregnancy hypertensive complications. Forty premenopausal women were recruited 10 years after delivery in a case-control study. Salt sensitivity was defined as an increase of >4 mm Hg in 24-hour ambulatory BP on a high-sodium diet. The ambulatory BP response to salt was significantly increased in women with a history of preeclampsia compared with that of controls. The mean (95% confidence interval) daytime systolic/diastolic BP increased significantly from 115 (109-118)/79 (76-82) mm Hg on low-salt diet to 123 (116-130)/80 (76-84) on a high-salt diet in women with preeclampsia, but not in the control group (from 111 [104-119]/77 [72-82] to 111 [106-116]/75 [72-79], respectively, P<0.05). The sodium sensitivity index (SSI=Δmean arterial pressure/Δurinary Na excretion×1000) was 51.2 (19.1-66.2) in women with preeclampsia and 6.6 (5.8-18.1) mm Hg/mol per day in controls (P=0.015). The nocturnal dip was blunted on a high-salt diet in women with preeclampsia. Our study shows that women who have developed preeclampsia are salt sensitive before their menopause, a finding that may contribute to their increased cardiovascular risk. Women with a history of severe preeclampsia should be targeted at an early stage for preventive measures of cardiovascular diseases.

Wind Loads on Dynamic Message Cabinets and Behavior of Supporting Trusses, TR-612, 2013

Large Dynamic Message Signs (DMSs) have been increasingly used on freeways, expressways and major arterials to better manage the traffic flow by providing accurate and timely information to drivers. Overhead truss structures are typically employed to support those DMSs allowing them to provide wider display to more lanes. In recent years, there is increasing evidence that the truss structures supporting these large and heavy signs are subjected to much more complex loadings than are typically accounted for in the codified design procedures. Consequently, some of these structures have required frequent inspections, retrofitting, and even premature replacement. Two manufacturing processes are primarily utilized on truss structures - welding and bolting. Recently, cracks at welding toes were reported for the structures employed in some states. Extremely large loads (e.g., due to high winds) could cause brittle fractures, and cyclic vibration (e.g., due to diurnal variation in temperature or due to oscillations in the wind force induced by vortex shedding behind the DMS) may lead to fatigue damage, as these are two major failures for the metallic material. Wind and strain resulting from temperature changes are the main loads that affect the structures during their lifetime. The American Association of State Highway and Transportation Officials (AASHTO) Specification defines the limit loads in dead load, wind load, ice load, and fatigue design for natural wind gust and truck-induced gust. The objectives of this study are to investigate wind and thermal effects in the bridge type overhead DMS truss structures and improve the current design specifications (e.g., for thermal design). In order to accomplish the objective, it is necessary to study structural behavior and detailed strain-stress of the truss structures caused by wind load on the DMS cabinet and thermal load on the truss supporting the DMS cabinet. The study is divided into two parts. The Computational Fluid Dynamics (CFD) component and part of the structural analysis component of the study were conducted at the University of Iowa while the field study and related structural analysis computations were conducted at the Iowa State University. The CFD simulations were used to determine the air-induced forces (wind loads) on the DMS cabinets and the finite element analysis was used to determine the response of the supporting trusses to these pressure forces. The field observation portion consisted of short-term monitoring of several DMS Cabinet/Trusses and long-term monitoring of one DMS Cabinet/Truss. The short-term monitoring was a single (or two) day event in which several message sign panel/trusses were tested. The long-term monitoring field study extended over several months. Analysis of the data focused on trying to identify important behaviors under both ambient and truck induced winds and the effect of daily temperature changes. Results of the CFD investigation, field experiments and structural analysis of the wind induced forces on the DMS cabinets and their effect on the supporting trusses showed that the passage of trucks cannot be responsible for the problems observed to develop at trusses supporting DMS cabinets. Rather the data pointed toward the important effect of the thermal load induced by cyclic (diurnal) variations of the temperature. Thermal influence is not discussed in the specification, either in limit load or fatigue design. Although the frequency of the thermal load is low, results showed that when temperature range is large the restress range would be significant to the structure, especially near welding areas where stress concentrations may occur. Moreover stress amplitude and range are the primary parameters for brittle fracture and fatigue life estimation. Long-term field monitoring of one of the overhead truss structures in Iowa was used as the research baseline to estimate the effects of diurnal temperature changes to fatigue damage. The evaluation of the collected data is an important approach for understanding the structural behavior and for the advancement of future code provisions. Finite element modeling was developed to estimate the strain and stress magnitudes, which were compared with the field monitoring data. Fatigue life of the truss structures was also estimated based on AASHTO specifications and the numerical modeling. The main conclusion of the study is that thermal induced fatigue damage of the truss structures supporting DMS cabinets is likely a significant contributing cause for the cracks observed to develop at such structures. Other probable causes for fatigue damage not investigated in this study are the cyclic oscillations of the total wind load associated with the vortex shedding behind the DMS cabinet at high wind conditions and fabrication tolerances and induced stresses due to fitting of tube to tube connections.

Brachial or wrist blood pressure in obese patients : which is the best ?

RESUME L'obésité et l'hypertension atteignent des niveaux épidémiques aussi bien dans les pays industrialisés que dans ceux en voie de développement. La coexistence de ces deux pathologies est associée à un risque cardiovasculaire augmenté. Traditionnellement on mesure la pression artérielle (PA) au bras au moyen d'un brassard qui détermine la pression systolique et diastolique en utilisant soit la méthode auscultatoire ou oscillométrique. L'utilisation d'un brassard de taille standard chez le patient avec un tour de bras augmenté peut surestimer la pression artérielle. Il semble même qu'il existe un rapport idéal entre le tour de bras, et la taille du brassard La mesure à domicile de la pression artérielle avec des appareils validés donne des valeurs de la PA valables. Plusieurs appareils existent sur le marché et depuis quelques années les appareils de mesure de la PA au poignet font leur apparition sur le marché. Cette étude vise à comparer chez des sujets sains et obèses les valeurs de PA obtenues au poignet avec celles obtenues au bras en utilisant deux appareils validés l'OMRON HEM 705-CP et l'OMRON R6. L'OMRON HEM 705-CP permet l'utilisation soit d'un brassard standard (13x30 cm) ou d'un brassard large (16x38 cm), et l'OMRON R6 mesure la PA au poignet. Nous avons comparé un groupe de sujets obèses [Body Mass Index (BMI) >35kg/m2] avec un groupe de sujets sains (BMI <25kg/m2). Ont été exclues de l'étudé les personnes prenant un traitement antihypertenseur ainsi que celles souffrant d'arythmies. La PA a été mesurée en position assise avec le bras gauche sur une table à hauteur du coeur. Un brassard large a été employé pour les sujets obèses et un brassard standard pour les sujets sains. Trois mesures ont été effectuées, la première après une pause de 5 min et chacune des suivantes avec un intervalle de 2 min. La pression d'inflation maximale a été fixée à 170 mmHg. Nous avons utilisé la formule proposée par Marks LA et al pour déterminer si le rapport entre la taille des brassards fournis avec l'OMRON .HEM 705-CP et le tour de bras de nos sujets était optimal (taille du brassard = 9.34 x log10 taille du bras). Nos résultats ne montrent pas de différence statistiquement significative de la PA diastolique entre les deux groupes, qu'elle soit mesurée au bras ou au poignet. La PA systolique mesurée au bras s'est par contre avérée significativement plus basse chez les sujets obèses que chez les sujets sains. Aucune différence n'a été trouvée lorsque la mesure est effectuée au poignet. En utilisant la formule fournie par Marks le rapport entre taille du brassard (large chez les obèses) et tour de bras a été de 10.30±30 chez les sujets obèses et 9.630.45 chez les sujets sains (p<0.001). Le rapport entre tour de bras et brassard chez les sujets obèses est nettement au-dessus de la valeur optimale, ce qui suggère une possible sous-estimation de la PA systolique chez ces sujets. Ces résultats suggèrent qu'il existe un risque de sous-estimer la PA chez le patient obèse lors de l'utilisation d'un brassard large. Cette erreur pourrait être réduite par l'utilisation d'appareils de mesure au poignet. validés chez le sujet obèse.

Unraveling the "pressure effect" in nucleation

The influence of the pressure of a chemically inert carrier gas on the nucleation rate is one of the biggest puzzles in the research of gas-liquid nucleation. Experiments can show a positive effect, a negative effect, or no effect at all. The same experiment may show both trends for the same substance depending on temperature, or for different substances at the same temperature. We show how this ambiguous effect naturally arises from the competition of two contributions: nonisothermal effects and pressure-volume work. Our model clarifies seemingly contradictory experimental results and quantifies the variation of the nucleation ability of a substance in the presence of an ambient gas. Our findings are corroborated by molecular dynamics simulations and might have important implications since nucleation in experiments, technical applications, and nature practically always occurs in the presence of an ambient gas.

Cardiac hypertrophy, low blood pressure, and low aldosterone levels in mice devoid of the three circadian PAR bZip transcription factors DBP, HLF, and TEF.

The cardiovascular system is under the control of the circadian clock, and disturbed circadian rhythms can induce cardiovascular pathologies. This cyclic regulation is probably brought about by the circadian expression of genes encoding enzymes and regulators involved in cardiovascular functions. We have previously shown that the rhythmic transcription of output genes is, in part, regulated by the clock-controlled PAR bZip transcription factors DBP (albumin D-element Binding Protein), HLF (Hepatic Leukemia Factor), and TEF (Thyrotroph Embryonic Factor). The simultaneous deletion of all three PAR bZip transcription factors leads to increased morbidity and shortened life span. Here, we demonstrate that Dbp/Tef/Hlf triple knockout mice develop cardiac hypertrophy and left ventricular dysfunction associated with a low blood pressure. These dysfunctions are exacerbated by an abnormal response to this low blood pressure characterized by low aldosterone levels. The phenotype of PAR bZip knockout mice highlights the importance of circadian regulators in the modulation of cardiovascular functions.