Effect of fecal water on an in vitro model of colonic mucosal barrier function

Fecal water (FW) has been shown to exert, in cultured cells, cytotoxic and genotoxic effects that have implications for colorectal cancer (CRC) risk. We have investigated a further biological activity of FW, namely, the ability to affect gap junctions in CACO2 cell monolayers as an index of mucosal barrier function, which is known to be disrupted in cancer. FW samples fi-om healthy, free-living, European subjects that were divided into two broad age groups, adult (40 +/- 9.7 yr; n = 53) and elderly (76 +/- 7.5 yr; n = 55) were tested for effects on gap junction using the transepithelial resistance (TER) assay. Overall, treatment of CACO2 cells with FW samples fi-om adults increased TER (+ 4 %), whereas FW from elderly subjects decreased TER (-5%); the difference between the two groups was significant (P < 0.05). We also measured several components of FW potentially associated with modulation of TER, namely, short-chain fatty acid (SCFA) and ammonia. SCFAs (propionic, acetic, and n-butyric) were significantly lower in the elderly population (-30%, -35%, and -21%, respectively, all P pound 0.01). We consider that FW modulation of in vitro epithelial barrier function is a potentially useful noninvasive biomarker, but it requires further validation to establish its relationship to CRC risk.

The effect of postnatal depression on mother-infant interaction, infant response to the still-face perturbation, and performance on an instrumental learning task

A representative community sample of primiparous depressed women and a nondepressed control group were assessed while in interaction with their infants at 2 months postpartum. At 3 months, infants were assessed on the Still-face perturbation of face to face interaction, and a subsample completed an Instrumental Learning paradigm. Compared to nondepressed women, depressed mothers' interactions were both less contingent and less affectively attuned to infant behavior. Postnatal depression did not adversely affect the infant's performance in either the Still-face perturbation or the Instrumental Learning assessment. Maternal responsiveness in interactions at 2 months predicted the infant's performance in the Instrumental Learning assessment but not in the Still-face perturbation. The implications of these findings for theories of infant cognitive and emotional development are discussed.

Comments on “An ensemble cumulus convection parameterization with explicit cloud treatment”

Wagner and Graf (2010) derive a population evolution equation for an ensemble of convective plumes, an analogue with the Lotka–Volterra equation, from the energy equations for convective plumes provided by Arakawa and Schubert (1974). Although their proposal is interesting, as the present note shows, there are some problems with their derivation.

Perspectives on an integrated construction project model

This paper reviews the growing interest in an integrated construction project model, and examines the fundamental concept of an integrated project model by discussing the various definitions that have evolved as well as the various approaches to its development. The nature of collaborative communications that the integrated project model needs to support is also discussed, as are the enabling information and communications technologies that may have a role in the realization of the model. The paper concludes with some thoughts on the future development of the integrated construction project model.

Understanding stakeholder requirements on an NHS hospital project: application of semiotics-rooted theories.

Hospitals represent complex and difficult contexts for AEC (architecture, engineering and construction) professionals to engage with due to their functional complexity and diversity of stakeholder interests (i.e. patient, visitor, medical specialist). Hospital designers need to take note of changing NHS policy contexts (e.g. the possible empowerment of general practitioners to shape services), technological advances in medical equipment design and the potential health needs of future generations. It is imperative for hospital designers and architects to align their processes and methodologies (e.g. briefing and requirements capture) to the needs and desires of their clients so that a medical facility design is produced which is truly aligned to the requirements of the hospital stakeholders. Semiotics, the “study” or “discipline” of signs aims to investigate the nature of signs (their inception, representation and meaning), whilst semiotics-rooted theories are concerned with investigating how meaning and understanding is mobilized between persons and between organisations. This paper details a semiotics-rooted research approach for investigating the interactions between hospital designers and stakeholders on a forthcoming NHS hospital project in the UK. A semiotics grounded study will potentially provide a deeper understanding of how meaning and understanding is established between hospital project stakeholders and construction professionals.

Commentary on an example of a tenancy agreement for an agricultural holding

This paper sets out an example of a standard agricultural tenancy, being one creating a tenancy from year to year and consequently covered by the agricultural holdings legislation. A facing-page commentary gives a clause-by-clause analysis of the agreement, the implications of each provision being discussed in the light of the law of contract, agricultural holdings legislation and, where appropriate, subsequent caselaw.

On an alleged truth/falsity asymmetry in context shifting experiments

Keith DeRose has argued that context shifting experiments should be designed in a specific way in order to accommodate what he calls a ‘truth/falsity asymmetry’. I explain and critique DeRose's reasons for proposing this modification to contextualist methodology, drawing on recent experimental studies of DeRose's bank cases as well as experimental findings about the verification of affirmative and negative statements. While DeRose's arguments for his particular modification to contextualist methodology fail, the lesson of his proposal is that there is good reason to pay close attention to several subtle aspects of the design of context shifting experiments.

A note on an integration by parts formula for the generators of uniform translations on configuration space

An integration by parts formula is derived for the first order differential operator corresponding to the action of translations on the space of locally finite simple configurations of infinitely many points on Rd. As reference measures, tempered grand canonical Gibbs measures are considered corresponding to a non-constant non-smooth intensity (one-body potential) and translation invariant potentials fulfilling the usual conditions. It is proven that such Gibbs measures fulfill the intuitive integration by parts formula if and only if the action of the translation is not broken for this particular measure. The latter is automatically fulfilled in the high temperature and low intensity regime.

Insights into the molecular architecture of a peptide nanotube using FTIR and solid-state NMR spectroscopic measurements on an aligned sample

The self-assembly of proteins and peptides into b-sheet-rich amyloid fibers is a process that has gained notoriety because of its association with human diseases and disorders. Spontaneous self-assembly of peptides into nonfibrillar supramolecular structures can also provide a versatile and convenient mechanism for the bottom-up design of biocompatible materials with functional properties favoring a wide range of practical applications.[1] One subset of these fascinating and potentially useful nanoscale constructions are the peptide nanotubes, elongated cylindrical structures with a hollow center bounded by a thin wall of peptide molecules.[2] A formidable challenge in optimizing and harnessing the properties of nanotube assemblies is to gain atomistic insight into their architecture, and to elucidate precisely how the tubular morphology is constructed from the peptide building blocks. Some of these fine details have been elucidated recently with the use of magic-angle-spinning (MAS) solidstate NMR (SSNMR) spectroscopy.[3] MAS SSNMR measurements of chemical shifts and through-space interatomic distances provide constraints on peptide conformation (e.g., b-strands and turns) and quaternary packing. We describe here a new application of a straightforward SSNMR technique which, when combined with FTIR spectroscopy, reports quantitatively on the orientation of the peptide molecules within the nanotube structure, thereby providing an additional structural constraint not accessible to MAS SSNMR.

Stability of an ice sheet on an elastic bed

The stability of stationary flow of a two-dimensional ice sheet is studied when the ice obeys a power flow law (Glen's flow law). The mass accumulation rate at the top is assumed to depend on elevation and span and the bed supporting the ice sheet consists of an elastic layer lying on a rigid surface. The normal perturbation of the free surface of the ice sheet is a singular eigenvalue problem. The singularity of the perturbation at the front of the ice sheet is considered using matched asymptotic expansions, and the eigenvalue problem is seen to reduce to that with fixed ice front. Numerical solution of the perturbation eigenvalue problem shows that the dependence of accumulation rate on elevation permits the existence of unstable solutions when the equilibrium line is higher than the bed at the ice divide. Alternatively, when the equilibrium line is lower than the bed, there are only stable solutions. Softening of the bed, expressed through a decrease of its elastic modulus, has a stabilising effect on the ice sheet.

Poor survival on an artificial diet of two genotypes of the aphid Myzus persicae: a fitness cost of insecticide resistance?

A fully susceptible genotype (4106A) of Myzus persicae survived the longest on an artificial diet and, in several of the eight replicates, monitoring was terminated when the culture was still thriving. A genotype with elevated carboxylesterase FE4 at the R3 level (800F) had a mean survival of only 98.13 days, whereas 794J, which combines R3 E4 carboxylesterase with target-site resistance (knockdown resistance), survived for the even shorter mean time of 84.38 days. The poorer survival of the two genotypes with extremely elevated carboxylesterase-resistance was not the result of a reluctance to transfer to new diet at each diet change. Although available for only two replicates, a revertant clone of 794J (794Jrev), which has the same genotype as 794J but the amplified E4 genes are not expressed leading to a fully susceptible phenotype, did not appear to survive any better than this clone. This suggests that the poor survival on an artificial diet of the extreme-carboxylesterase genotypes is not the result of the cost of over-producing the enzyme. The frequency of insecticide-resistant genotypes is low in the population until insecticide is applied, indicating that they have reduced fitness, although this does not necessarily reflect a direct cost of expressing the resistance mechanism.