Fixed twist dynamics of SO(3) gauge theory

We perform a throughout study of 3+1 dim. SO(3) LGT for any fixed-twist background. We concentrate in particular on the physically significant trivial and 1-twist sectors. Introducing a Z(2) monopole chemical potential the 1st order bulk transition is moved down in the strong coupling region and weakened to 2nd order in the 4-dim Ising model universality class. In this extended phase diagram we gain access to a confined phase in every fixed twist sector of the theory. The Pisa disorder operator is employed together with the Polyakov loop to study the confinement-deconfinement transition in each sector. Due to the specific properties of both operators, most results can be used to gain insight in the ergodic theory, where all twist sectors should be summed upon. An explicit mapping of each fixed twist theory to effective positive plaquette models with fixed twisted boundary conditions is applied to better establish their properties in the different phases.Comment: 20 pages, 11 Figures. Minor changes in text and figures, to appear in Eur.Phys.J.

Tissue Targeted Embryonic Chimeras: Zebrafish Gastrula Cell Transplantation

Certain fundamental questions in the field of developmental biology can only be answered when cells are placed in novel environments or when small groups of cells in a larger context are altered. Watching how one cell interacts with and behaves in a unique environment is essential to characterizing cell functions. Determining how the localized misexpression of a specific protein influences surrounding cells provides insightful information on the roles that protein plays in a variety of developmental processes. Our lab uses the zebrafish model system to uniquely combine genetic approaches with classical transplantation techniques to generate genotypic or phenotypic chimeras. We study neuron-glial cell interactions during the formation of forebrain commissures in zebrafish. This video describes a method that allows our lab to investigate the role of astroglial populations in the diencephalon and the roles of specific guidance cues that influence projecting axons as they cross the midline. Due to their transparency zebrafish embryos are ideal models for this type of ectopic cell placement or localized gene misexpression. Tracking transplanted cells can be accomplished using a vital dye or a transgenic fish line expressing a fluorescent protein. We demonstrate here how to prepare donor embryos with a vital dye tracer for transplantation, as well as how to extract and transplant cells from one gastrula staged embryo to another. We present data showing ectopic GFP+ transgenic cells within the forebrain of zebrafish embryos and characterize the location of these cells with respect to forebrain commissures. In addition, we show laser scanning confocal timelapse microscopy of Alexa 594 labeled cells transplanted into a GFP+ transgenic host embryo. These data provide evidence that gastrula staged transplantation enables the targeted positioning of ectopic cells to address a variety of questions in Developmental Biology

Universality, vortices and confinement: modified SO(3) lattice gauge theory at non-zero temperature

We investigate the adjoint SU(2) lattice gauge theory in 3+1 dimensions with the Wilson plaquette action modified by a Z(2) monopole suppression term. For the zero-twist sector we report indications for the existence of a finite temperature effect decoupled from the unphysical bulk transitions.Comment: 17 pages, 10 figures. Some figures and text added. To appear on Phys. Rev.

Effect of vacuum induced nucleation on the final product homogeneity

In the field of freeze drying of pharmaceutics the homogeneity of the sublimation flux during drying is fundamental to allow a final product with the same characteristics. Previous studies have shown that the control of freezing stage, in addition to a dramatic reduction of cycle duration, can also improve the homogeneity of the final batch. In this framework, this study is focused on the investigation of the effects of the Vacuum Induced Nucleation control method (modified in a previous work)[1,2] on the final structure of the product. Two aspects will be taken into consideration: the uniformity among vials of the same batch (inter-vial) and the uniformity of the structure along the height of the product (intra-vial). It has to be pointed out that a non-uniform product structure can have an impact on the protein aggregation and redistribution, and cause a partial cake collapse or micro-collapse. This investigation is really useful to define some limits of the control method used in this work

Anxiety and Depression as Comorbid Factors in Drinking Behaviors of Undergraduate College Students Attending an Urban Private University in the Northeastern United States

High-risk drinking is the number one public health concern on college campuses (Berkowitz, 2003; Kapner, 2003; Wechsler, 2002). To date, high-risk drinking prevention programs have met with limited success (Kapner, 2003). This study examined differences among four drinking behavior groups: non-drinkers [(ND), (n = 128)], low-risk drinkers [(LRD), (n = 252)], high-risk drinkers [(HRD), (n = 272)], and frequent high-risk drinkers [(FHRD), (n = 290)] with respect to anxiety and depression for male (n = 457) and female (n = 485) undergraduates (N = 942) attending an urban private university in the northeastern United States; and, the perceptions of two undergraduate focus groups (N = 10) and one faculty/staff group (N = 14) for why undergraduates engage in high-risk drinking and actions to reduce this behavior. Volunteer participants completed a demographic questionnaire, the Alcohol Use Disorders Identification Test, the Beck Anxiety Inventory, and the Beck Depression Inventory. An ANOVA indicated differences among the groups with respect to anxiety (F = 6.49, p \u3c .001), but not with respect to depression. The FHRD group had higher anxiety (M = .68) than the ND group (M = .33) and the LRD group (M = .44). A t-test indicated differences (p \u3c .01) in the level of anxiety between HRD females (M = .69) and HRD males (M = .40), with no differences for depression. A chi-square analysis indicated differences between males and females with respect to drinking behavior group classification (χ² = 22.40, df = 3, p = .001). Focus group results suggested several reasons why students engage in high-risk drinking: it is the norm, easy access to alcohol, low accountability for drinking, cope with anxiety, relieve boredom, lift depression, cope with anger, family history of alcohol use, alcohol dependence, and poor self-esteem. Implications for educators are discussed

Preparation of bio-functional textiles by surface functionalization of cellulose fabrics with caffeine loaded nanoparticles

In recent years transdermal drug delivery has aroused significant interest as a sustained and non-invasive way of administering active substances. The development of nanotechnology allowed the development of novel pharmaceutical formulations overcoming skin barrier. Furthermore, such nano-system can be combined with conventional fabrics to pave the way to a new generation of wearable drug delivery devices: bio-functional garments. First the NP were produced by flash nanoprecipitation technique (FNP), the production process was optimized to produce particles with suitable size for transdermal applications. The nanoparticles were characterized in terms of drug content by UV-visible spectroscopy and in terms of antioxidant activity by Electron Paramagnetic Resonance spectroscopy (EPR) coupled with spin trapping technique. The NPs were used to functionalize cotton and viscose-micromodal fabrics and the transdermal release properties were tested in vitro by Franz’s Cell experiment. FNP was proven to be an effective technique to produce tunable size particles. Moreover, the nanoencapsulated drug exhibited antioxidant activity. The release test evidenced a controlled release behavior effect providing evidence that the bio-functional textile is suitable for applications where sustained release and antioxidant properties are required

SO(3) versus SU(2) lattice gauge theory

We consider the SO(3) lattice gauge theory at weak coupling, in the Villain action. We exhibit an analytic path in coupling space showing the equivalence of the SO(3) theory with SU(2) summed over all twist sectors. This clarifies the ``mysterious phase'' of SO(3). As order parameter, we consider the dual string tension or center vortex free energy, which we measure in SO(3) using multicanonical Monte Carlo. This allows us to set the scale, indicating that ${\cal O}(700)^4$ lattices are necessary to probe the confined phase. We consider the relevance of our findings for confinement in other gauge groups with trivial center.Comment: 12 pages, 6 figures, to appear in the Proceedings of the NATO workshop on "Confinement, Topology, and other Non-Perturbative Aspects of QCD", Stara Lesna, Feb. 200