Experiments with metallic and ceramic porous media

Work in the area of mechano-caloric phenomena was initiated during 1988 with startup in the Summer 1988 period. The ideal system utilizing He-II super-phenomena is modeled readily, within the frame of thermodynamics energetics, using the concept of an ideal superleak. The real system however uses porous media of non-ideal pore-grain ingredients. The early phase of experimental and related modeling studies is outlined for the time period from Summer 1988 to the end of 1988

Homotheties and topology of tangent sphere bundles

We prove a Theorem on homotheties between two given tangent sphere bundles $S_rM$ of a Riemannian manifold $M,g$ of $\dim\geq 3$, assuming different variable radius functions $r$ and weighted Sasaki metrics induced by the conformal class of $g$. New examples are shown of manifolds with constant positive or with constant negative scalar curvature, which are not Einstein. Recalling results on the associated almost complex structure $I^G$ and symplectic structure ${\omega}^G$ on the manifold $TM$, generalizing the well-known structure of Sasaki by admitting weights and connections with torsion, we compute the Chern and the Stiefel-Whitney characteristic classes of the manifolds $TM$ and $S_rM$.Comment: 15 pages, to appear in Journal of Geometr

Thermomechanical force application

The present work conducted in Summer 1987 continues investigations on Thermal Components for 1.8 K Space Cryogenics (Grant NAG 1-412 of 1986). The topics addressed are plug characterization efforts in a small pore size regime of sintered metal plugs, characterization in the nonlinear regime, temperature profiles in a heat supply unit for a fountain effect pump and modeling efforts

Utilization of FEP energetics

The research and development work on Fountain Effect Pump Systems (FEP systems) has been of interest in the competition between mechanical pumps for He II and FEP units. The latter do not have moving parts. In the course of the work, the energetics have been addressed using one part of a simple four-changes-of-state cycle. One option is the FEP ideal change of state at constant chemical potential (mu). The other option is the two-state sequence mu-P with a d mu=0 state change followed by an isobar. Questions of pump behavior, of flow rate response to temperature difference at the hot end, and related questions of thermodynamic cycle completion and heat transfer have been addressed. Porous media data obtained elucidate differences between vapor-liquid phase separation (VLPS) and Zero Net Mass Transfer (ZNMF)

Vertically Self-Gravitating ADAFs in the Presence of Toroidal Magnetic Field

Force due to the self-gravity of the disc in the vertical direction is considered to study its possible effects on the structure of a magnetized advection-dominated accretion disc. We present steady-sate self similar solutions for the dynamical structure of such a type of the accretion flows. Our solutions imply reduced thickness of the disc because of the self-gravity. It also imply that the thickness of the disc will increase by adding the magnetic field strength.Comment: Accepted for publication in Astrophysics and Space Science

SIRENIA FOSSILS FROM QOM FORMATION (BURDIGALIAN) OF THE KABUDAR AHANG AREA, NORTHWEST IRAN

Fossil remains of sirenians (Mammalia; Dugongidae) are reported from the late early Miocene (Burdigalian) Qom Formation near the town of Shirin Su, northwest Kabudar Ahang region, west of Tehran, Iran. The fossils consist of partial postcranial skeletons preserved mostly as natural molds in limestone. In the absence of skulls or other diagnostic elements, it is not evident which dugongid subfamily these specimens represent: Halitheriinae or Dugonginae. Both subfamilies were present in contemporaneous Western Tethys (Mediterranean) deposits, but so far only dugongines have been found in Neogene rocks of Eastern Tethys. Since the Iranian deposits are located between these two parts of the former Tethys Seaway, it will be interesting to see which group(s) the Iranian sirenians prove to represent, once their taxonomic identity has been determined through future discoveries

Testing Unimodular Gravity

We consider models of gravitation that are based on unimodular general coordinate transformations (GCT). These transformations include only those which do not change the determinant of the metric. We treat the determinant as a separate field which transforms as a scalar under unimodular GCT. We consider a class of such theories. In general, these theories do not transform covariantly under the full GCT. We characterize the violation of general coordinate invariance by introducing a new parameter. We show that the theory is consistent with observations for a wide range of this parameter. This parameter may serve as a test for possible violations of general coordinate invariance. We also consider the cosmic evolution within the framework of these models. We show that in general we do not obtain consistent cosmological solutions if we assume the standard cosmological constant or the standard form of non-relativistic matter. We propose a suitable generalization which is consistent with cosmology. We fit the resulting model to the high redshift supernova data. We find that we can obtain a good fit to this data even if include only a single component, either cosmological constant or non-relativistic matter.Comment: 14 pages one figure, significantly revised with several new results adde

Mapping Local Cytosolic Enzymatic Activity in Human Esophageal Mucosa with Porous Silicon Nanoneedles

Porous silicon nanoneedles can map Cathepsin B activity across normal and tumor human esophageal mucosa. Assembling a peptide‐based Cathepsin B cleavable sensor over a large array of nano­needles allows the discrimination of cancer cells from healthy ones in mixed culture. The same sensor applied to tissue can map Cathepsin B activity with high resolution across the tumor margin area of esophageal adenocarcinoma. [Image: see text

Energy-momentum Distribution in Static and Non-static Cosmic String Space-times

We elaborate the problem of energy-momentum in general relativity by energy-momentum prescriptions theory. In this regard, we calculate M\oller,Landau-Lifshitz, Papapetrou, Einstein, Bergman, Tolman, and Weinberg's energy-momentum complexes in static and nonstatic cosmic string space-times. We obtain strong coincidences between the results. These coincidences can be considered as an extension of Virbhadra's viewpoint that different energy-momentum prescriptions may provide some basis to define a unique quantity. In addition, our results disagree with Lessner's belief about M\oller's prescription and support the Virbhadra's conclusion about the power of Einstein's prescription.Comment: LaTeX, 5 page: added reference

Fundoplication to preserve allograft function after lung transplant: Systematic review and meta-analysis

Background: ARS has been adopted in select patients with lung transplant for the past 2 decades inmany centers. Outcomes have been reported sporadically. No pooled analysis of retrospective series has been performed. Objective: This review and pooled analysis sought to demonstrate objective evidence of improved graft function in lung transplant patients undergoing antireflux surgery (ARS). Methods: In accordance with Meta-analyses of Observational Studies in Epidemiology guidelines, a search of PubMed Central, Medline, Google Scholar, and Cochrane Library databases was performed. Articles documenting spirometry data pre- and post-ARS were reviewed and a random-effects model meta-analysis was performed on forced expiratory volume in 1 second (FEV1) values and the rate of change of FEV1. Results: Six articles were included in the meta-analysis. Regarding FEV1 before and after ARS, we observed a small increase in FEV1 values in studies reporting raw values (2.02 ± 0.89 L/1 sec vs 2.14 ± 0.77 L/1 sec; n = 154) and % of predicted (77.1% ± 22.1% vs 81.2% ± 26.95%; n = 45), with a small pooled Cohen d effect size of 0.159 (P = .114). When considering the rate of change of FEV1 we observed a significant difference in pre-ARS compared with post-ARS (–2.12 ± 2.76 mL/day vs +0.05 ± 1.19 mL/day; n = 103). There was a pooled effect size of 1.702 (P = .013), a large effect of ARS on the rate of change of FEV1 values. Conclusions: This meta-analysis of retrospective observational studies demonstrates that ARS might benefit patients with declining FEV1, by examining the rate of change of FEV1 during the pre- and postoperative periods