932 resultados para Dov Baer, of Mezhirech, d. 1772
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Exposure of the skin to sunlight can cause skin cancer and is also necessary for cutaneous vitamin D production. Media reports have highlighted the purported health benefits of vitamin D. Our aim was to examine attitudes and behaviours related to sun protection and vitamin D. A cross-sectional study of 2,001 residents in Queensland, Australia aged 20-70 years was undertaken. Information collected included: skin cancer risk factors; perceptions about levels of sun exposure required to maintain vitamin D; belief that sun protection increases risk of vitamin D deficiency; intention, and actual change in sun protection practices for adults and children. Multivariate models examined predictors of attitudinal and behavioural change. One-third (32%) believed a fair-skinned adult, and 31% thought a child required at least 30 minutes per day in summer sun to maintain vitamin D levels. Reductions in sun protection were reported by 21% of adults and 14% of children. Factors associated with belief that sun protection may result in not obtaining enough vitamin D included aged ≥ 60 years (OR=1.35, 95% CI 1.09-1.66) and having skin that tanned easily (OR=1.96, 95% CI 1.38-2.78). Participants from low income households, and those who frequently used sun protective clothing were more likely to have reduced sun protection practices (OR=1.33, 95% CI 1.10-1.73 and OR=1.73, 95% CI 1.36-2.20, respectively). This study provides evidence of reductions in sun protection practices in a population living in a high UV environment. There is an urgent need to re-focus messages regarding sun exposure and for continued sun protection practices.
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Objective: To assess the recall of media reports about vitamin D and associated factors. Methods: Analysis of cross-sectional telephone interview data (2,001 Queensland adults, 18-70 years) on vitamin D and personal sun protection, recall of media reports and participant characteristics. Results: 83.7% of participants had heard of vitamin D, 47.5% through the media. Only 513 (25.6%) participants recalled the media content within four main themes: vitamin D is beneficial/comes from the sun (47.0%); some people aren’t getting enough vitamin D, need more sun (27.9%); need to balance sun exposure and skin protection (11.5%); or other (13.6%). Only 65 of the 950 participants (6.8%) reported a change to their behaviour(s) due to the media report. Conclusion: Although the media were the main source of information about vitamin D for almost 50% of participants, recall of the content and direct effect on behaviour was low. Only a small minority recalled a balanced media report of beneficial and harmful aspects of sun exposure. Implications Health professionals often supply media with background information. To achieve best public health practice for sun protection and vitamin D, information to foster balanced media reports should be provided.
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The case of Re Baby D (No. 2) has been described as a “landmark decision” as to whether parents themselves can authorise medical staff to withdraw life-sustaining treatment from their child or are required to seek the permission of a court or tribunal. The reasons for the decision that the removal of an endotracheal tube from the airway of Baby D was to treat “a bodily malfunction or disease” and therefore could be authorised by the parents will be explored.
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Observational studies suggest that people with a high serum 25-hydroxyvitamin D (25(OH)D) concentration may have reduced risk of chronic diseases such as osteoporosis, multiple sclerosis, type 1 diabetes, cardiovascular disease, and some cancers. The AusD Study (A Quantitative Assessment of Solar UV Exposure for Vitamin D Synthesis in Australian Adults) was conducted to clarify the relationships between ultraviolet (UV) radiation exposure, dietary intake of vitamin D, and serum 25(OH)D concentration among Australian adults residing in Townsville (19.3°S), Brisbane (27.5°S), Canberra (35.3°S), and Hobart (42.8°S). Participants aged 18-75 years were recruited from the Australian Electoral Roll between 2009 and 2010. Measurements were made of height, weight, waist:hip ratio, skin, hair, and eye color, blood pressure, and grip strength. Participants completed a questionnaire on sun exposure and vitamin D intake, together with 10 days of personal UV dosimetry and an associated sun-exposure and physical-activity diary that was temporally linked to a blood test for measurement of 25(OH)D concentration. Ambient solar UV radiation was also monitored at all study sites. We collected comprehensive, high-quality data from 1,002 participants (459 males, 543 females) assessed simultaneously across a range of latitudes and through all seasons. Here we describe the scientific and methodological issues considered in designing the AusD Study.
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Background: Plasma D-dimer tests are currently used to exclude deep vein thrombosis and pulmonary embolism. Human saliva has numerous advantages over blood as a diagnostic sample. The aims of our study were to develop a reliable immunoassay to detect D-dimer levels in saliva, and to determine the correlation between salivary and blood D-dimer levels. Results/methodology: Saliva and blood samples were collected from 40 healthy volunteers. We developed a AlphaLISA((R)) immunoassay with acceptable analytical performances to quantify D-dimer levels in the samples. The median salivary D-dimer levels were 138.1 ng/ml (morning) and 140.7 ng/ml (afternoon), and the plasma levels were 75.0 ng/ml. Salivary D-dimer levels did not correlate with plasma levels (p = 0.61). Conclusion: For the first time, we have quantified D-dimer levels and found twofold increase in saliva (p < 0.05) than in plasma. Further studies are required to demonstrate the clinical relevance/utility of salivary D-dimer in patients with confirmed deep vein thrombosis and/or pulmonary embolism.
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Meat/meat alternatives (M/MA) are key sources of Fe, Zn and protein, but intake tends to be low in young children. Australian recommendations state that Fe-rich foods, including M/MA, should be the first complementary foods offered to infants. The present paper reports M/MA consumption of Australian infants and toddlers, compares intake with guidelines, and suggests strategies to enhance adherence to those guidelines. Mother–infant dyads recruited as part of the NOURISH and South Australian Infants Dietary Intake studies provided 3 d of intake data at three time points: Time 1 (T1) (n 482, mean age 5·5 (SD 1·1) months), Time 2 (T2) (n 600, mean age 14·0 (SD 1·2) months) and Time 3 (T3) (n 533, mean age 24 (SD 0·7) months). Of 170 infants consuming solids and aged greater than 6 months at T1, 50 (29 %) consumed beef, lamb, veal (BLV) or pork on at least one of 3 d. Commercial infant foods containing BLV or poultry were the most common form of M/MA consumed at T1, whilst by T2 BLV mixed dishes (including pasta bolognaise) became more popular and remained so at T3. The processed M/MA increased in popularity over time, led by pork (including ham). The present study shows that M/MA are not being eaten by Australian infants or toddlers regularly enough; or in adequate quantities to meet recommendations; and that the form in which these foods are eaten can lead to smaller M/MA serve sizes and greater Na intake. Parents should be encouraged to offer M/MA in a recognisable form, as one of the first complementary foods, in order to increase acceptance at a later age.
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Reactive oxygen species (ROS) mediated modulation of signal transduction pathways represent an important mechanism of cell injury and barrier dysfunction leading to the development of vascular disorders. Towards understanding the role of ROS in vascular dysfunction, we investigated the effect of diperoxovanadate (DPV), derived from mixing hydrogen peroxide and vanadate, on the activation of phospholipase D (PLD) in bovine pulmonary artery endothelial cells (BPAECs). Addition of DPV to BPAECs in the presence of .05% butanol resulted in an accumulation of [P-32] phosphatidylbutanol (PBt) in a dose- and time-dependent manner. DPV also caused an increase in tyrosine phosphorylation of several protein bands (Mr 20-200 kD), as determined by Western blot analysis with antiphosphotyrosine antibodies. The DPV-induced [P-32] PBt-accumulation was inhibited by putative tyrosine kinase inhibitors such as genistein, herbimycin, tyrphostin and by chelation of Ca2+ with either EGTA or BAPTA, however, pretreatment of BPAECs with the inhibitor PKC bisindolylmaleimide showed minimal inhibition. Also down-regulation of PKC alpha and epsilon, the major isotypes of PKC in BPAECs, by TPA (100 nM, 18 h) did not attenuate the DPV-induced PLD activation. The effects of putative tyrosine kinase and PKC inhibitors were specific as determined by comparing [P-32] PBt formation between DPV and TPA. In addition to tyrosine kinase inhibitors, antioxidants such as N-acetylcysteine and pyrrolidine dithiocarbamate also attenuated DPV-induced protein tyrosine phosphorylation and PLD stimulation. These results suggest that oxidation, prevented by reduction with thiol compounds, is involved in DPV-dependent protein tyrosine phosphorylation and PLD activation.
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Using a multivalley effective mass theory, we obtain the binding energy of a D- ion in Si and Ge taking into account the spatial variation of the host dielectric function. We find that on comparison with experimental results the effect of spatial dispersion is important in the estimation of binding energy for the D- formed by As in Si and Ge. The effect is less significant for the case of D- formed by P and Sb donors.
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A detailed investigation of the d.c. polarographic behaviour of vanadium(V),-(IV) and -(III) in glycine solutions has been made keeping the total glycine concentration at 0.1, 0.5 and 1.0 M and varying the pH of the solution. Experiments keeping the pH constant (using different ratios of glycine and glycine anion) and varying the glycine anion concentration, and also in predominantly anion solutions, have been made.
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Introduction Recent reports have highlighted the prevalence of vitamin D deficiency and suggested an association with excess mortality in critically ill patients. Serum vitamin D concentrations in these studies were measured following resuscitation. It is unclear whether aggressive fluid resuscitation independently influences serum vitamin D. Methods Nineteen patients undergoing cardiopulmonary bypass were studied. Serum 25(OH)D3, 1α,25(OH)2D3, parathyroid hormone, C-reactive protein (CRP), and ionised calcium were measured at five defined timepoints: T1 - baseline, T2 - 5 minutes after onset of cardiopulmonary bypass (CPB) (time of maximal fluid effect), T3 - on return to the intensive care unit, T4 - 24 hrs after surgery and T5 - 5 days after surgery. Linear mixed models were used to compare measures at T2-T5 with baseline measures. Results Acute fluid loading resulted in a 35% reduction in 25(OH)D3 (59 ± 16 to 38 ± 14 nmol/L, P < 0.0001) and a 45% reduction in 1α,25(OH)2D3 (99 ± 40 to 54 ± 22 pmol/L P < 0.0001) and i(Ca) (P < 0.01), with elevation in parathyroid hormone (P < 0.0001). Serum 25(OH)D3 returned to baseline only at T5 while 1α,25(OH)2D3 demonstrated an overshoot above baseline at T5 (P < 0.0001). There was a delayed rise in CRP at T4 and T5; this was not associated with a reduction in vitamin D levels at these time points. Conclusions Hemodilution significantly lowers serum 25(OH)D3 and 1α,25(OH)2D3, which may take up to 24 hours to resolve. Moreover, delayed overshoot of 1α,25(OH)2D3 needs consideration. We urge caution in interpreting serum vitamin D in critically ill patients in the context of major resuscitation, and would advocate repeating the measurement once the effects of the resuscitation have abated.
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An acyclic edge coloring of a graph is a proper edge coloring such that there are no bichromatic cycles. The acyclic chromatic index of a graph is the minimum number k such that there is an acyclic edge coloring using k colors and is denoted by a'(G). It was conjectured by Alon, Suclakov and Zaks (and earlier by Fiamcik) that a'(G) <= Delta+2, where Delta = Delta(G) denotes the maximum degree of the graph. Alon et al. also raised the question whether the complete graphs of even order are the only regular graphs which require Delta+2 colors to be acyclically edge colored. In this article, using a simple counting argument we observe not only that this is not true, but in fact all d-regular graphs with 2n vertices and d>n, requires at least d+2 colors. We also show that a'(K-n,K-n) >= n+2, when n is odd using a more non-trivial argument. (Here K-n,K-n denotes the complete bipartite graph with n vertices on each side.) This lower bound for Kn,n can be shown to be tight for some families of complete bipartite graphs and for small values of n. We also infer that for every d, n such that d >= 5, n >= 2d+3 and dn even, there exist d-regular graphs which require at least d+2-colors to be acyclically edge colored. (C) 2009 Wiley Periodicals, Inc. J Graph Theory 63: 226-230, 2010.
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Titration calorimetry measurements of the binding of phenyl-alpha (alpha PhOGlu), 3-methoxy (3MeOGlu), fluorodeoxy and deoxy derivatives of alpha-D-glucopyranose (Glu) to concanavalin A (conA), pea lectin and lentil lectin were performed at approx. 10 and 25 degrees C in 0.01 M dimethylglutaric acid/NaOH buffer, pH 6.9, containing 0.15 M NaCl and Mn2+ and Ca2+ ions. Apparently the 3-deoxy, 4-deoxy and 6-deoxy as well as the 4-fluorodeoxy and 6-fluorodeoxy derivatives of Glu do not bind to the lectins because no heat release was observed on the addition of aliquots of solutions of these derivatives to the lectin solutions. The binding enthalpies, delta H0b, and entropies, delta S0b, determined from the measurements were compared with the same thermodynamic binding parameters for Glu, D-mannopyranoside and methyl-alpha- D-glucopyranoside (alpha MeOGlu). The binding reactions are enthalpically driven with little change in the heat capacity on binding, and exhibit enthalpy-entropy compensation. Differences between the thermodynamic binding parameters can be rationalized in terms of the interactions apparent in the known crystal structures of the methyl-alpha-D-mannopyranoside-conA [Derewenda, Yariv, Helliwell, Kalb (Gilboa), Dodson, Papiz, Wan and Campbell (1989) EMBO J. 8, 2189-2193] and pea lectin-trimanno-pyranoside [Rini, Hardman, Einspahr, Suddath and Carber (1993) J. Biol. Chem. 268, 10126-10132] complexes. Increases in the entropy change on binding are observed for alpha MeOGlu binding to pea and lentil lectin, for alpha PhOGlu binding to conA and pea lectin, and for 3MeOGlu binding to pea lectin relative to the entropy change for Glu binding, and imply that the phenoxy and methoxy substituents provide additional hydrophobic interactions in the complex. Increases in the binding enthalpy relative to that of Glu are observed for deoxy and fluoro derivatives in the C-1 and C-2 positions and imply that these substituents weaken the interaction with the surrounding water, thereby strengthening the interaction with the binding site.
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The crystal structure of a hexamer duplex d(CACGTG)(2) has been determined and refined to an R-factor of 18.3% using X-ray data up to 1.2 angstrom resolution. The sequence crystallizes as a left-handed Z-form double helix with Watson-Crick base pairing. There is one hexamer duplex, a spermine molecule, 71 water molecules, and an unexpected diamine (Z-5, 1,3-propanediamine, C3H10N2)) in the asymmetric unit. This is the high-resolution non-disordered structure of a Z-DNA hexamer containing two AT base pairs in the interior of a duplex with no modifications such as bromination or methylation on cytosine bases. This structure does not possess multivalent cations such as cobalt hexaammine that are known to stabilize Z-DNA. The overall duplex structure and its crystal interactions are similar to those of the pure-spermine form of the d(CGCGCG)(2) structure. The spine of hydration in the minor groove is intact except in the vicinity of the T5A8 base pair. The binding of the Z-5 molecule in the minor grove of the d(CACGTG)(2) duplex appears to have a profound effect in conferring stability to a Z-DNA conformation via electrostatic complementarity and hydrogen bonding interactions. The successive base stacking geometry in d(CACGTG)(2) is similar to the corresponding steps in d(CG)(3). These results suggest that specific polyamines such as Z-5 could serve as powerful inducers of Z-type conformation in unmodified DNA sequences with AT base pairs. This structure provides a molecular basis for stabilizing AT base pairs incorporated into an alternating d(CG) sequence.
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For d >= 2, Walkup's class K (d) consists of the d-dimensional simplicial complexes all whose vertex-links are stacked (d - 1)-spheres. Kalai showed that for d >= 4, all connected members of K (d) are obtained from stacked d-spheres by finitely many elementary handle additions. According to a result of Walkup, the face vector of any triangulated 4-manifold X with Euler characteristic chi satisfies f(1) >= 5f(0) - 15/2 chi, with equality only for X is an element of K(4). Kuhnel observed that this implies f(0)(f(0) - 11) >= -15 chi, with equality only for 2-neighborly members of K(4). Kuhnel also asked if there is a triangulated 4-manifold with f(0) = 15, chi = -4 (attaining equality in his lower bound). In this paper, guided by Kalai's theorem, we show that indeed there is such a triangulation. It triangulates the connected sum of three copies of the twisted sphere product S-3 (sic) S-1. Because of Kuhnel's inequality, the given triangulation of this manifold is a vertex-minimal triangulation. By a recent result of Effenberger, the triangulation constructed here is tight. Apart from the neighborly 2-manifolds and the infinite family of (2d + 3)-vertex sphere products Sd-1 X S-1 (twisted for d odd), only fourteen tight triangulated manifolds were known so far. The present construction yields a new member of this sporadic family. We also present a self-contained proof of Kalai's result. (C) 2011 Elsevier B.V. All rights reserved.
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Synthesis, crystal structures, linear and nonlinear optical properties of tris D-pi-A cryptand derivatives with C-3 symmetry are reported. Three fold symmetry inherent in the cryptand molecules has been utilized for designing these molecules. Molecular nonlinearities have been measured by hyper-Rayleigh scattering (HRS) experiments. Among the compounds studied, L-1 adopts non-centrosymmetric crystal structure. Compounds L-1, L-2, L-3 and L-4 show a measurable SHG powder signal. These molecules are more isotropic and have significantly higher melting points than the classical p-nitroaniline based dipolar NLO compounds, making them useful for further device applications. Besides, different acceptor groups can be attached to the cryptand molecules to modulate their NLO properties.