Systems models for infrastructures

The paper analyzes the equations which model the growth of human populations and the accompanying infrastructure developments which are required to support the corresponding societies because of their direct or implicit dependence upon human needs. Systems methods are employed to treat the coupled non-linear phenomena, and numerical examples are displayed. The fundamental nature of the models is found to be logistic, and there is switching at critical points between regimes or phases of growth.     

Phenolics of Vaccinium berries and other fruit crops

The concentrations and profiles of phenolics of selected fruit crops common in the Western diet, including several Vaccinium species, were examined to better understand how these crops may be useful sources of phenolic phytochemicals. Vaccinium fruit had a high phenolic concentration compared to non‐Vaccinium fruit. Some Vaccinium fruit were particularly rich in certain phenolic subgroups, especially anthocyanins and pro‐anthocyanidins. Among the pro‐anthocyanidin oligomers measured using fluorometric and mass spectroscopic detection, the trimers and tetramers were most abundant, while pro‐anthocyanidins with a degree of polymerization greater than 8 were least abundant. As biomedical studies determine which phenolic structures are associated with particular bioactivities, information on the phenolic concentration and profile of selected species will be useful in developing specific uses for fruit crops in human health. Methods were compared to assess the usefulness of simpler versus more sophisticated means of phenolic analysis. The phenolic components of fruit extracts were purified approximately 20‐fold, and not qualitatively altered, by C18 solid‐phase extraction. However, fruit extracts obtained from C18 solid‐phase extraction differed in their relative abundance of phenolic components. Colorimetric and HPLC‐DAD measures of phenolic concentration were correlated (R² = 0.79), as was pro‐anthocyanidin concentration detected fluorometrically and by mass spectrometry (R² = 0.44). Copyright © 2007 Crown in the right of Canada and Society of Chemical Industry     

电子邮件营销:因资源与投资回报失衡而被低估

博客和业内专家认为,电子邮件营销面临的最大挑战非常复杂,如收件箱传输能力或渲染。这是真的吗?一名博学的市场人员、设计师或程序员都可以轻易解决上述两个问题,而对于其他大多数人来说,问题就不是那么简单了。这才是真正的问题。大多数公司并不知道电子邮件营销的最佳实践,同时他们内部也缺少相关的专业资源。然而,却很少有公司意识到这个问题,因为即使是写得很糟糕的电子邮件似乎仍表现不错。未造成伤害,也没有犯错,不是吗?     

Effect of trace Na additions on the hydriding kinetics of hypo-eutectic Mg–Ni alloys

Mg–Ni alloys are among the most promising candidates for solid-state hydrogen storage systems. This paper reveals the effect of Na doping in accelerating initial hydrogen uptake in Mg–Ni alloys using in-situ Synchrotron X-ray powder diffraction. A minimum concentration of approximately 0.2 wt.% Na must be achieved for the alloys to show reasonably fast hydriding kinetics. Surface analysis shows that a Na-modified Mg–Ni surface facilitates the chemisorption and dissociation of hydrogen molecules in the early stage of hydriding as evidenced by a rapid formation of the saturated hydrogen solid solution Mg₂NiH_0.3 from the original Mg₂Ni. The subsequent hydrogen absorption is based on a mechanism of nucleation and growth of MgH₂ where a high density of dislocations develops ahead of the growing hydride-metal interface.     

Inhaled PYY(3–36) dry-powder formulation for appetite suppression

Objective: Peptide YY3–36 [PYY(3–36)] has shown efficacy in appetite suppression when dosed by injection modalities (intraperitoneal (IP)/subcutaneous). Transitioning to needle-free delivery, towards inhalation, often utilizes systemic pharmacokinetics as a key endpoint to compare different delivery methods and doses. Systemic pharmacokinetics were evaluated for PYY3–36 when delivered by IP, subcutaneous, and inhalation, the systemic pharmacokinetics were then used to select doses in an appetite suppression pharmacodynamic study.

Methods: Dry-powder formulations were manufactured by spray drying and delivered to mice via nose only inhalation. The systemic plasma, lung tissue, and bronchoalveolar lavage fluid pharmacokinetics of different inhalation doses of PYY(3–36) were compared to IP and subcutaneous efficacious doses. Based on these pharmacokinetic data, inhalation doses of 70:30 PYY(3–36):Dextran T10 were evaluated in a mouse model of appetite suppression and compared to IP and subcutaneous data.

Results: Inhalation pharmacokinetic studies showed that plasma exposure was similar for a 2?×?higher inhalation dose when compared to subcutaneous and IP delivery. Inhalation doses of 0.22 and 0.65?mg/kg were for efficacy studies. The results showed a dose-dependent (not dose proportional) decrease in food consumption over 4?h, which is similar to IP and subcutaneous delivery routes.

Conclusions: The pharmacokinetic and pharmacodynamics results substantiate the ability of pharmacokinetic data to inform pharmacodynamics dose selection for inhalation delivery of the peptide PYY(3–36). Additionally, engineered PYY(3–36):Dextran T10 particles delivered to the respiratory tract show promise as a non-invasive therapeutic for appetite suppression.     

Bactericidal Effects of HVOF-Sprayed Nanostructured TiO2 on Pseudomonas aeruginosa

Titanium dioxide (TiO₂) has been shown to exhibit photocatalytic bactericidal activity. This preliminary study focused on examining the photocatalytic activity of high-velocity oxy-fuel (HVOF) sprayed nanostructured TiO₂ coatings to kill Pseudomonas aeruginosa. The surfaces of the nanostructured TiO₂ coatings were lightly polished before addition of the bacterial solution. Plates of P. aeruginosa were grown, and then suspended in a phosphate buffer saline (PBS) solution. The concentration of bacteria used was determined by a photo-spectrometer, which measured the amount of light absorbed by the bacteria-filled solution. This solution was diluted and pipetted onto the coating, which was exposed to white light in 30-min intervals, up to 120 min. It was found that on polished HVOF-sprayed coatings exposed to white light, 24% of the bacteria were killed after exposure for 120 min. On stainless steel controls, approximately 6% of the bacteria were not recovered. These preliminary results show that thermal-sprayed nanostructured TiO₂ coatings exhibited photocatalytic bactericidal activity with P. aeruginosa.     

The structure of latherin,a surfactant allergen protein from horse sweat and saliva

Latherin is a highly surface-active allergen protein found in the sweat and saliva of horses and other equids. Its surfactant activity is intrinsic to the protein in its native form, and is manifest without associated lipids or glycosylation. Latherin probably functions as a wetting agent in evaporative cooling in horses, but it may also assist in mastication of fibrous food as well as inhibition of microbial biofilms. It is a member of the PLUNC family of proteins abundant in the oral cavity and saliva of mammals, one of which has also been shown to be a surfactant and capable of disrupting microbial biofilms. How these proteins work as surfactants while remaining soluble and cell membrane-compatible is not known. Nor have their structures previously been reported. We have used protein nuclear magnetic resonance spectroscopy to determine the conformation and dynamics of latherin in aqueous solution. The protein is a monomer in solution with a slightly curved cylindrical structure exhibiting a ‘super-roll’ motif comprising a four-stranded anti-parallel β-sheet and two opposing α-helices which twist along the long axis of the cylinder. One end of the molecule has prominent, flexible loops that contain a number of apolar amino acid side chains. This, together with previous biophysical observations, leads us to a plausible mechanism for surfactant activity in which the molecule is first localized to the non-polar interface via these loops, and then unfolds and flattens to expose its hydrophobic interior to the air or non-polar surface. Intrinsically surface-active proteins are relatively rare in nature, and this is the first structure of such a protein from mammals to be reported. Both its conformation and proposed method of action are different from other, non-mammalian surfactant proteins investigated so far.     

Improving the effectiveness of computer-delivered personalized drinking feedback interventions for college students.

This study evaluated methods of enhancing college students' retention of information provided to them in a computer-delivered personalized drinking feedback intervention and whether enhanced retention reduced alcohol consumption during the two-week period following the intervention. Participants were 98 college students who reported at least one heavy drinking episode in the past two weeks. After participating in an online, personalized drinking feedback intervention, students were randomly assigned to one of three experimental conditions: 1) typical, in which they were simply sent home, 2) reading, in which they were asked to spend the next 20 minutes re-reading the feedback, and 3) recall, in which they were asked to spend the next 20 minutes writing down as much of the information from the feedback as they could remember. Two weeks following the intervention, participants completed a recall test and provided information on their alcohol use during the previous two weeks. Results indicated that participants in the reading and recall conditions retained more of the feedback information than did participants in the typical condition. In addition, participants in the reading and recall conditions reported reduced alcohol consumption in the two-week period following the intervention, compared to those in the typical condition. Information retention partially mediated the effects of the reading and recall conditions on drinking outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Method for three-dimensional data registration from disparate imaging modalities in the NOGA Myocardial Viability Trial

Region-by-region comparison of data concerning left ventricular (LV) status is difficult to perform quantitatively if the data was acquired from disparate imaging modalities. We validated a method for comparing measurements obtained by electromechanical mapping (EMM) catheter with dobutamine stress echocardiography (DSE) via biplane contrast ventriculography, with the assistance of three-dimensional (3-D) echocardiographic data. The ventriculograms were traced and the borders were used to reconstruct the LV in 3-D with the aid of a database of 3-D echocardiographic studies. The 3-D LV was oriented to the EMM data based on the body coordinates and then manually scaled and translated to fit. The EMM data were mapped to the 3-D surface. The 3-D surface was divided into the 16 regions defined for echocardiographic assessment. The mean EMM value for local linear shortening, a parameter of function, was computed in each segment. The EMM and semiquantitative echocardiographic assessments of regional myocardial function were compared by segment, and the volume of the 3-D LV was compared with the volume computed from the ventriculogram. The volume of the 3-D surface correlated closely with that of the ventriculogram (r = 0.97, SEE = 27.4 ml) but with a significant overestimation of 63 +/- 35 ml. There was a highly significant (p < 0.0001) agreement in regional function between EMM and echo. Local linear shortening correlated significantly (p < 0.0001) with echocardiographic severity of wall motion, averaging 9.5 +/- 6.5, 8.1 +/- 5.4, 5.9 +/- 4.8, and 6.2 +/- 3.3 in segments read as normal, hypokinetic, akinetic, and dyskinetic, respectively. The method presented is valid for comparing cardiac parameters derived from disparate image data on a region-by-region basis by employing anatomic landmarks on 3-D reconstructions of the LV endocardial surface.     

Loss of emotional experience after traumatic brain injury: Findings with the startle probe procedure.

The authors used affective modulation of the eyeblink startle response to examine the impact of traumatic brain injury (TBI) on emotional reactions to pictures. Participants were 13 individuals with severe TBI and 24 controls. Participants were presented with pictures that differed in affective valence (e.g., mutilated bodies, erotic couples, and household objects) while the eyeblink startle response to an acoustic probe was measured. Startle amplitude was used to assess valence of emotional response, and startle latency was used to index interest in the pictures. Subjective ratings of the affect and arousal elicited by the various pictures were also obtained. TBI impaired startle potentiation to unpleasant pictures but not startle attenuation to pleasant pictures. Further, subjective ratings indicated that TBI participants found unpleasant pictures less arousing than did controls. The results are consistent with recent evidence of differential impairment in negative versus positive emotions after TBI and are discussed in relation to 2 competing explanations of startle modulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)