Critical temperature for first-order phase transitions in confined systems

We consider the Euclidean $D$-dimensional $-\lambda |\phi |^4+\eta |\phi |^6$ ($\lambda ,\eta >0$) model with $d$ ($d\leq D$) compactified dimensions. Introducing temperature by means of the Ginzburg--Landau prescription in the mass term of the Hamiltonian, this model can be interpreted as describing a first-order phase transition for a system in a region of the $D$-dimensional space, limited by $d$ pairs of parallel planes, orthogonal to the coordinates axis $x_1, x_2, ..., x_d$. The planes in each pair are separated by distances $L_1, L_2, ..., L_d$. We obtain an expression for the transition temperature as a function of the size of the system, $$, $i=1, 2, ..., d$. For D=3 we particularize this formula, taking $L_1=L_2=... =L_d=L$ for the physically interesting cases $d=1$ (a film), $d=2$ (an infinitely long wire having a square cross-section), and for $d=3$ (a cube). For completeness, the corresponding formulas for second-order transitions are also presented. Comparison with experimental data for superconducting films and wires shows qualitative agreement with our theoretical expressionsComment: REVTEX, 11 pages, 3 figures; to appear in Eur. Phys. Journal

International credit market connections

Some test cases show how credit markets couple and decouple constantly, creating a complex web of international financial relationships.International finance ; Credit

Video verite : thoughts on Scenes from underground.

Thesis (M.S.V.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1984.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHIncludes bibliographical references (leaves 29-30).This thesis considers the making of a documentary videotape on the Red Line Subway Extension project in Cambridge and Somerville, Massachusetts entitled Scenes From Underground. It traces my initial plans for an expository 16mm film on the Red Line construction work occurring alongside Harvard University in Harvard Square. It then t ells of how the influence of one-person cinema verite filmmaking resulted in the similar use of light-weight video tape recording equipment, and the subsequent utilization of this equipment in the tunnels and subway station construction sites of the Red Line Extension project. The paper asserts that the video medium is ideally suited for a non-preconceived approach to documentary work and that the rules and conventions governing observational filmmaking are applicable to video. The videotape Scenes From Underground is 37 minutes long and was originally shot on 1/2 " VHS and 3/4" U-matic cassette. It has black and white and color sequences, and the sound track is in English.by Barry Strongin.M.S.V.S

A method of producing high quality oxide and related films on surfaces

Aluminum oxide or aluminum nitride films were deposited on molecular beam epitaxy (MBE) grown GaAS(100) using a novel cryogenic-based reactive thin film deposition technique. The process involves the condensation of molecular oxygen, ammonia, or other gases normally used for reactive thin film deposition on the substrate before the metal is deposited. The metal vapor is deposited into this layer and reacts with the molecular solid to form the desired compound or a precursor that can be thermally decomposed to generate the desired compound. The films produced by this method are free of impurities, and the low temperatures can be used to control the film and interfacial structure. The process can be easily integrated with existing MBE systems. Ongoing research using the same apparatus suggests that photon or electron irradiation could be used to promote the reactions needed to produce the intended material

Role of confined phonons in thin film superconductivity

We calculate the critical temperature $T_c$ and the superconducting energy gaps $\Delta_n$ of a thin film superconductor system, where $\Delta_n$ is the superconducting energy gap of the $n$-th subband. Since the quantization of both the electron energy and phonon spectrum arises due to dimensional confinement in one direction, the effective electron-electron interaction mediated by the quantized confined phonons is different from that mediated by the bulk phonon, leading to the modification of $T_c$ in the thin film system. We investigate the dependence of $T_c$ and $\Delta_n$ on the film thickness $d$ with this modified interaction.Comment: 4 pages, 2 figure

Selective function-blocking monoclonal human antibody highlights the important role of membrane type-1 matrix metalloproteinase (MT1-MMP) in metastasis.

The invasion-promoting MT1-MMP is a cell surface-associated collagenase with a plethora of critical cellular functions. There is a consensus that MT1-MMP is a key protease in aberrant pericellular proteolysis in migrating cancer cells and, accordingly, a promising drug target. Because of high homology in the MMP family and a limited success in the design of selective small-molecule inhibitors, it became evident that the inhibitor specificity is required for selective and successful MT1-MMP therapies. Using the human Fab antibody library (over 1.25×109 individual variants) that exhibited the extended, 23-27 residue long, VH CDR-H3 segments, we isolated a panel of the inhibitory antibody fragments, from which the 3A2 Fab outperformed others as a specific and potent, low nanomolar range, inhibitor of MT1-MMP. Here, we report the in-depth characterization of the 3A2 antibody. Our multiple in vitro and cell-based tests and assays, and extensive structural modeling of the antibody/protease interactions suggest that the antibody epitope involves the residues proximal to the protease catalytic site and that, in contrast with tissue inhibitor-2 of MMPs (TIMP-2), the 3A2 Fab inactivates the protease functionality by binding to the catalytic domain outside the active site cavity. In agreement with the studies in metastasis by others, our animal studies in acute pulmonary melanoma metastasis support a key role of MT1-MMP in metastatic process. Conversely, the selective anti-MT1-MMP monotherapy significantly alleviated melanoma metastatic burden. It is likely that further affinity maturation of the 3A2 Fab will result in the lead inhibitor and a proof-of-concept for MT1-MMP targeting in metastatic cancers

A policymakers' guide to economic forecasts

Forecasting ; Economic policy

Apoptotic and chemotherapeutic properties of iron(III)-salophene in an ovarian cancer animal model

The cytotoxicity of organometallic compounds iron(III)-, cobalt(III)-, manganese(II)-, and copper(II)-salophene (-SP) on platinum-resistant ovarian cancer cell lines was compared. Fe-SP displayed selective cytotoxicity (IC 50 at ∼1 μM) against SKOV-3 and OVCAR-3 cell lines while Co-SP caused cytotoxic effects only at higher concentrations (IC50 at 60 ?M) and Cu-SP effects were negligible. High cytotoxicity of Mn-SP (30-60 μM) appeared to be nonspecific because the Mn-chloride salt reduced cell viability similarly. The effect of Fe-SP at 1 μM proved to be ovarian cancer cell selective when compared to a panel of cell lines derived from different tumors. The first irreversible step in the induction of cell death by Fe-SP occurred after 3 hrs as indicated by the mitochondrial transmembrane potential (ΔΨm) and was mainly linked to apoptotic, not necrotic events. To evaluate the toxicity of Fe-SP in vivo we conducted an acute toxicity study in rats. The LD 50 of Fe-SP is >2000 mg/kg orally and >5.5 mg/kg body weight by intraperitoneal injection. An ovarian cancer animal model showed that the chemotherapeutic relevant dose of Fe-SP in rats is 0.5-1 mg/kg body weight. The present report suggests that Fe-SP is a potential therapeutic drug to treat ovarian cancer. © 2009 Lange et al, publisher and licensee Dove Medical Press Ltd