Scanning-gate microscopy of semiconductor nanostructures: an overview

This paper presents an overview of scanning-gate microscopy applied to the imaging of electron transport through buried semiconductor nanostructures. After a brief description of the technique and of its possible artifacts, we give a summary of some of its most instructive achievements found in the literature and we present an updated review of our own research. It focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. In all of the given examples, we emphasize how a local-probe approach is able to shed new, or complementary, light on transport phenomena which are usually studied by means of macroscopic conductance measurements.Comment: Invited talk by SH at 39th "Jaszowiec" International School and Conference on the Physics of Semiconductors, Krynica-Zdroj, Poland, June 201

Developing "BUILDING/ FACILITY ENERGY CONSUMPTION DATA SHEET" for Political Subdivisions, Institutions of Higher Education, and State Agencies, to Satisfy Senate Bill 898 (82nd R) Reporting Requirements

As mandated by the 82nd R Legislature (2011), Senate Bill 898, Health and Safety Code, Section 388.005, beginning September 1, 2011, each political subdivision, institution of higher education or state agency shall establish a goal to reduce the electric consumption by the entity by at least 5% each state fiscal year for 10 years. Each entity annually is to report to the State Energy Conservation Office (SECO), on forms provided by SECO, regarding the entity's goal, the entity's efforts to meet the goal, and progress the entity has made. An entity that does not attain the 5% goal must include in the report justification that the entity has already implemented all available cost-effective measures. SECO is to annually provide the commission and the Energy Systems Laboratory (Laboratory) with an evaluation of the effectiveness of state and political subdivision energy efficiency programs. The Laboratory is mandated to calculate, based on the evaluation and the forms submitted to the office, the amount of energy savings and estimated reduction in pollution achieved as a result of the implementation of the programs, and then provide the information to the Texas Commission on Environmental Quality, the United States Environmental Protection Agency, and the Electric Reliability Council of Texas to help with long-term forecasting and in estimating pollution reduction. During the first quarter of 2012, the Laboratory, working with SECO, devised and proposed to SECO a standardized form for use by political subdivisions, institutions of higher education and state agencies in order to satisfy the new reporting requirements set by Senate Bill 898. The form contains the minimum information needed to show an accurate estimated energy savings and estimated reduction in pollution as a result of the implementation of the programs. In July 2012, the basic form proposed by the ESL was enhanced electronically so that the form could be filled on a computer and emailed back, and the data could be pulled automatically. The form that was proposed to SECO by the ESL appears on the next page (showing default dates that could be changed by the submitter)

Analysis of Code-Compliant Construction in Texas Based on Texas Building Energy Performance Standards (TBEPS)

This paper presents a detailed technical analysis comparing the stringency of the Texas Building Energy Performance Standards (TBEPS), based on Chapter 11 of the 2009 International Residential Code (IRC) for residential construction and Chapter 5 of the 2009 International Energy Conservation Code (IECC) for commercial construction, to the recently published editions of the IRC and IECC: 2012 IRC for residential construction and 2012 IECC for commercial construction. A series of simulations were performed using the Laboratory's single-family and large commercial office building simulation models based on the DOE-2.1e program and the appropriate TMY2 weather files for three counties representing three 2009 IECC and 2012 IECC Climate Zones across Texas: Harris County for Climate Zone 2, Tarrant County for Climate Zone 3, and Potter County for Climate Zone 4. The analysis determined that the residential provisions of 2012 IRC are more stringent than the 2009 IRC that used the relevant 2009 IECC residential provisions, which is one of the two paths to comply with the 2009 IRC per Section N1101.2 of the code. The annual total source energy savings of the 2012 IRC ranges from 16.3% to 21.4% with the performance path and from 14.3% to 20.1% with the prescriptive path, depending on the climate zone and the heating system type of a house. The analysis for large office buildings also determined that the commercial provisions of 2012 IECC are more stringent that the 2009 IECC. The annual total site energy savings of the 2012 IECC ranges from 7.3% to 11.6% based on site energy use and from 4.1% to 7.0% based on source energy use, depending on the climate zone

Disruption of ph dynamics suppresses proliferation and potentiates doxorubicin cytotoxicity in breast cancer cells

The reverse pH gradient is a major feature associated with cancer cell reprogrammed metabolism. This phenotype is supported by increased activity of pH regulators like ATPases, carbonic anhydrases (CAs), monocarboxylate transporters (MCTs) and sodium–proton exchangers (NHEs) that induce an acidic tumor microenvironment, responsible for the cancer acid-resistant phenotype. In this work, we analyzed the expression of these pH regulators and explored their inhibition in breast cancer cells as a strategy to enhance the sensitivity to chemotherapy. Expression of the different pH regulators was evaluated by immunofluorescence and Western blot in two breast cancer cell lines (MDA-MB-231 and MCF-7) and by immunohistochemistry in human breast cancer tissues. Cell viability, migration and invasion were evaluated upon exposure to the pH regulator inhibitors (PRIs) concanamycin-A, cariporide, acetazolamide and cyano-4-hydroxycinnamate. Additionally, PRIs were combined with doxorubicin to analyze the effect of cell pH dynamic disruption on doxorubicin sensitivity. Both cancer cell lines expressed all pH regulators, except for MCT1 and CAXII, only expressed in MCF-7 cells. There was higher plasma membrane expression of the pH regulators in human breast cancer tissues than in normal breast epithelium. Additionally, pH regulator expression was significantly associated with different molecular subtypes of breast cancer. pH regulator inhibition decreased cancer cell aggressiveness, with a higher effect in MDA-MB-231. A synergistic inhibitory effect was observed when PRIs were combined with doxorubicin in the breast cancer cell line viability. Our results support proton dynamic disruption as a breast cancer antitumor strategy and the use of PRIs to boost the activity of conventional therapy.This research was funded by National funds, through the Foundation for Science and Technology (FCT) - project UIDB/50026/2020 and UIDP/50026/2020; and by the projects NORTE-01-0145-FEDER-000013 and NORTE-01-0145-FEDER-000023, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work was also supported by an internal CESPU project MetabRes_CESPU_2017. DT-V received a fellowship from FCT (ref. SFRH/BD/103025/2014)

Transport inefficiency in branched-out mesoscopic networks: An analog of the Braess paradox

We present evidence for a counter-intuitive behavior of semiconductor mesoscopic networks that is the analog of the Braess paradox encountered in classical networks. A numerical simulation of quantum transport in a two-branch mesoscopic network reveals that adding a third branch can paradoxically induce transport inefficiency that manifests itself in a sizable conductance drop of the network. A scanning-probe experiment using a biased tip to modulate the transmission of one branch in the network reveals the occurrence of this paradox by mapping the conductance variation as a function of the tip voltage and position.Comment: 2nd version with minor stylistic corrections. To appear in Phys. Rev. Lett.: Editorially approved for publication 6 January 201

Description and Comparison of the Results of the Proposed House: Habitat for Humanity at Frazier Court, Dallas, Texas, with the 2004 IECC Standard Reference House

The Energy Systems Laboratory was requested to calculate the emissions reductions associated with the Habitat for Humanity Housing Project at Frazier Court, Dallas Texas. This report presents the results of the required analysis, a set of houses was compared to a corresponding standard reference house as described in the 2004 International Energy Conservation Code (2004 IECC). The energy consumption calculations were carried out using DOE-2.1e input file RES3ST.inp (Version 4.01.07) and DDP (Version: 1.7.03). Based on this comparison, the % above/below code for the proposed house was determined. The resultant emissions calculations were carried out using eCALC software (ESL, 2006). This report also contains detailed information about the description of the proposed house in terms of its building parameters, resultant energy consumption and emission reductions. Calculations are carried out using TMY2 weather file for Tarrant County, TX which is in climate zone 3 of the IECC 2004 climate zone categories. For the 1285 sq. ft. houses, the energy consumption of the Habitat for Humanity houses is in the range of 10.3% - 11.7% above code and for the 843 sq. ft. houses, the energy consumption is in the range of 20.9% - 21.4% below code. The HERS ratings calculated by IC3 is in the range of 71.7– 74.2 for the 1285 sq. ft. houses and in the range of 79.4 – 80.6 for the 843 sq. ft. houses

Increased pathogenicity of pneumococcal serotype 1 is driven by rapid autolysis and release of pneumolysin

Streptococcus pneumoniae serotype 1 is the predominant cause of invasive pneumococcal disease in sub-Saharan Africa, but the mechanism behind its increased invasiveness is not well understood. Here, we use mouse models of lung infection to identify virulence factors associated with severe bacteraemic pneumonia during serotype-1 (ST217) infection. We use BALB/c mice, which are highly resistant to pneumococcal pneumonia when infected with other serotypes. However, we observe 100% mortality and high levels of bacteraemia within 24 hours when BALB/c mice are intranasally infected with ST217. Serotype 1 produces large quantities of pneumolysin, which is rapidly released due to high levels of bacterial autolysis. This leads to substantial levels of cellular cytotoxicity and breakdown of tight junctions between cells, allowing a route for rapid bacterial dissemination from the respiratory tract into the blood. Thus, our results offer an explanation for the increased invasiveness of serotype 1

Development of a non-dairy probiotic fermented rice food with bifidobacterium animalis and streptococcus thermophilus

info:eu-repo/semantics/publishedVersio

Linking epigenetics and biological conservation: Towards a conservation epigenetics perspective

International audience1. Biodiversity conservation is a global issue where the challenge is to integrate all levels of biodiversity to ensure the long-term evolutionary potential and resilience of biological systems. Genetic approaches have largely contributed to conservation biology by defining "conservation entities" accounting for their evolutionary history and adaptive potential, the so-called evolutionary significant units (ESUs). Yet, these approaches only loosely integrate the short-term ecological history of organisms. 2. Here, we argue that epigenetic variation, and more particularly DNA methylation, represents a molecular component of biodiversity that directly links the genome to the environment. As such, it provides the required information on the ecological background of organisms for an integrative field of conservation biology. 3. We synthesize knowledge about the importance of epigenetic mechanisms in (a) orchestrating fundamental development alternatives in organisms, (b) enabling individuals to respond in real-time to selection pressures and (c) improving ecosystem stability and functioning. 4. Using practical examples in conservation biology, we illustrate the relevance of DNA methylation (a) as biomarkers of past and present environmental stress events as well as biomarkers of physiological conditions of individuals; (b) for documenting the ecological structuring/clustering of wild populations and hence for better integrating ecology into ESUs; (c) for improving conservation transloca-tions; and (d) for studying landscape functional connectivity. 5. We conclude that an epigenetic conservation perspective will provide environmental managers the possibility to refine ESUs, to set conservation plans taking into account the capacity of organisms to rapidly cope with environmental changes, and hence to improve the conservation of wild populations. K E Y W O R D S conservation, DNA methylation, ecological timescales, epigenetic, evolutionary significant unit