Tissue-specific regulation of sirtuin and nicotinamide adenine dinucleotide biosynthetic pathways identified in C57Bl/6 mice in response to high-fat feeding

Funding: The Scottish Government's Rural and Environment Science and Analytical Services Division.Peer reviewedPostprin

Outcome of pregnancy in the era of highly active antiretroviral: a 10-year experience in Southern Ireland

Introduction: Since the introduction of HAART the desire to become a mother in women with HIV has become a viable option due to the drastic reduction in vertical transmission. The aim of this study was to look at the epidemiology, clinical characteristics, and safety of antiretroviral drugs and rate of vertical transmission in our cohort in the Munster region, Ireland. Methods: We retrospectively reviewed all pregnant women with HIV who attended the ID clinic from January 2002 to April 2012. Patients’ demographics, pertinent laboratory data, and pharmacy records were reviewed and statistically analysed. Results: 105 HIV-positive women, with a total of 165 pregnancies, were seen from January 2002 to April 2012 at Cork University Hospital: 46 patients were previously known to be HIV-infected at their first pregnancy and 59 were diagnosed during antenatal screening (median of 32 week gestation at diagnosis). The median age at the time of pregnancy was 32 and the HIV transmission was 90% sexual: 39 women were from Europe/Asia and 66 were African; only two women were HCV co-infected and one was HBV co-infected. Of the patients diagnosed with HIV prior to pregnancy, 13 were on treatment, all of whom had no detectable virus at the start and during pregnancy. The median CD4+ at the start of pregnancy was 490 cells/µl. The median weeks of gestation at the start of HAART was 28 before 2006 and 20 after 2006, in accordance with National Guidelines. The HAART regime used was in line with current Guidelines. 18 pregnancies ended in miscarriage before week 12 gestation and 2 pregnancies resulted in intrauterine death at 28 weeks. 145 pregnancies progressed to delivery at full term but 10 infants were born before the 37th week, with one baby born at 23 weeks: 63 had SVD and 82 underwent C-section, of whom 12 emergency C-section due to prolonged membrane rupture. Most of the C-sections were planned due to obstetric reasons. 2 infants were born HIV+: in one case the mother was a late presenter at 38 of gestation; and in other the mother had poor compliance with viral load detectable at the time of labour. The overall number of pregnancies per year has been stable over the ten years (average of 14 pregnancies per year). Conclusion: The use of cART with high level of adherence and a close clinical management during pregnancy has shown to dramatically reduce the vertical transmission of HIV in our cohort

Movement patterns of cheetahs ( Acinonyx jubatus ) in farmlands in Botswana

Botswana has the second highest population of cheetah (Acinonyx jubatus) with most living outside protected areas. As a result, many cheetahs are found in farming areas which occasionally results in human-wildlife conflict. This study aimed to look at movement patterns of cheetahs in farming environments to determine whether cheetahs have adapted their movements in these human-dominated landscapes. We fitted high-time resolution GPS collars to cheetahs in the Ghanzi farmlands of Botswana. GPS locations were used to calculate home range sizes as well as number and duration of visits to landscape features using a time-based local convex hull method. Cheetahs had medium-sized home ranges compared to previously studied cheetah in similar farming environments. Results showed that cheetahs actively visited scent marking trees and avoided visiting homesteads. A slight preference for visiting game farms over cattle farms was found, but there was no difference in duration of visits between farm types. We conclude that cheetahs selected for areas that are important for their dietary and social needs and prefer to avoid human-occupied areas. Improved knowledge of how cheetahs use farmlands can allow farmers to make informed decisions when developing management practices and can be an important tool for reducing human-wildlife conflict

S_3 and the L=1 Baryons in the Quark Model and the Chiral Quark Model

The S_3 symmetry corresponding to permuting the positions of the quarks within a baryon allows us to study the 70-plet of L=1 baryons without an explicit choice for the spatial part of the quark wave functions: given a set of operators with definite transformation properties under the spin-flavor group SU(3) x SU(2) and under this S_3, the masses of the baryons can be expressed in terms of a small number of unknown parameters which are fit to the observed L=1 baryon mass spectrum. This approach is applied to study both the quark model and chiral constituent quark model. The latter theory leads to a set of mass perturbations which more satisfactorily fits the observed L=1 baryon mass spectrum (though we can say nothing, within our approach, about the physical reasonableness of the parameters in the fit). Predictions for the mixing angles and the unobserved baryon masses are given for both models as well as a discussion of specific baryons.Comment: 24 pages, requires picte

Some observations on the renormalization of membrane rigidity by long-range interactions

We consider the renormalization of the bending and Gaussian rigidity of model membranes induced by long-range interactions between the components making up the membrane. In particular we analyze the effect of a finite membrane thickness on the renormalization of the bending and Gaussian rigidity by long-range interactions. Particular attention is paid to the case where the interactions are of a van der Waals type.Comment: 11 pages RexTex, no figure

The field theory of symmetrical layered electrolytic systems and the thermal Casimir effect

We present a general extension of a field-theoretic approach developed in earlier papers to the calculation of the free energy of symmetrically layered electrolytic systems which is based on the Sine-Gordon field theory for the Coulomb gas. The method is to construct the partition function in terms of the Feynman evolution kernel in the Euclidean time variable associated with the coordinate normal to the surfaces defining the layered structure. The theory is applicable to cylindrical systems and its development is motivated by the possibility that a static van der Waals or thermal Casimir force could provide an attractive force stabilising a dielectric tube formed from a lipid bilayer, an example of which are t-tubules occurring in certain muscle cells. In this context, we apply the theory to the calculation of the thermal Casimir effect for a dielectric tube of radius $R$ and thickness $\delta$ formed from such a membrane in water. In a grand canonical approach we find that the leading contribution to the Casimir energy behaves like $-k_BTL\kappa_C/R$ which gives rise to an attractive force which tends to contract the tube radius. We find that $\kappa_C \sim 0.3$ for the case of typical lipid membrane t-tubules. We conclude that except in the case of a very soft membrane this force is insufficient to stabilise such tubes against the bending stress which tend to increase the radius. We briefly discuss the role of lipid membrane reservoir implicit in the approach and whether its nature in biological systems may possibly lead to a stabilising mechanism for such lipid tubes.Comment: 28 pages, 2 figures, LaTe

Wrapping Transition and Wrapping-Mediated Interactions for Discrete Binding along an Elastic Filament: An Exact Solution

The wrapping equilibria of one and two adsorbing cylinders are studied along a semi-flexible filament (polymer) due to the interplay between elastic rigidity and short-range adhesive energy between the cylinder and the filament. We show that statistical mechanics of the system can be solved exactly using a path integral formalism which gives access to the full effect of thermal fluctuations, going thus beyond the usual Gaussian approximations which take into account only the contributions from the minimal energy configuration and small fluctuations about this minimal energy solution. We obtain the free energy of the wrapping-unwrapping transition of the filament around the cylinders as well as the effective interaction between two wrapped cylinders due to thermal fluctuations of the elastic filament. A change of entropy due to wrapping of the filament around the adsorbing cylinders as they move closer together is identified as an additional source of interactions between them. Such entropic wrapping effects should be distinguished from the usual entropic configuration effects in semi-flexible polymers. Our results may be applicable to the problem of adsorption of proteins as well as synthetic nano-particles on semi-flexible polymers such as DNA.Comment: 24 pages, 12 figure