Charged-phonon theory and Fano effect in the optical spectroscopy of bilayer graphene

Since their discovery, graphene-based systems represent an exceptional playground to explore the emergence of peculiar quantum effects. The present paper focuses on the anomalous appearence of strong infrared phonon resonances in the optical spectroscopy of bilayer graphene and on their pronounced Fano-like asymmetry, both tunable in gated devices. By developing a full microscopic many-body approach for the optical phonon response we explain how both effects can be quantitatively accounted for by the quantum interference of electronic and phononic excitations. We show that the phonon modes borrow a large dipole intensity from the electronic background, the so-called charged-phonon effect, and at the same time interfer with it, leading to a typical Fano response. Our approach allows one to disentangle the correct selection rules that control the relative importance of the two (symmetric and antisymmetric) relevant phonon modes for different values of the doping and/or of the gap in bilayer graphene. Finally, we discuss the extension of the same theoretical scheme to the Raman spectroscopy, to explain the lack of the same features on the Raman phononic spectra. Besides its remarkable success in explaining the existing experimental data in graphene-based systems, the present theoretical approach offers a general scheme for the microscopic understanding of Fano-like features in a wide variety of other systems.Comment: 16 pages, 11 eps figures, PR

Infrared phonon activity in pristine graphite

We study experimentally and theoretically the Fano-shaped phonon peak at 1590 cm$^{-1}$ (0.2 eV) in the in-plane optical conductivity of pristine graphite. We show that the anomalously large spectral weight and the Fano asymmetry of the peak can be qualitatively accounted for by a charged-phonon theory. A crucial role in this context is played by the particle-hole asymmetry of the electronic $\pi$-bands.Comment: 5 pages, 4 figures, 1 tabl

Sex-Dimorphic Interactions of MAOA Genotype and Child Maltreatment Predispose College Students to Polysubstance Use

This work is licensed under a Creative Commons Attribution 4.0 International License.Polysubstance use (PSU) is highly prevalent among college students. Recent evidence indicates that PSU is based on gene x environment (G×E) interactions, yet the specific biosocial factors underlying this problem remain elusive. We recently reported that lifetime use of tobacco and cannabis in college students is influenced by the interaction of the X-linked MAOA (monoamine oxidase A) gene and child maltreatment. Building on these premises, here we evaluated whether the same G×E interaction may also predict PSU in this population. Students of a large Midwestern university (n = 470; 50.9% females) took part in a computer survey for substance use, as well as childhood trauma exposure, using the Child Trauma Questionnaire (CTQ). DNA was extracted from their saliva samples and genotyped for MAOA variable-number of tandem repeat (VNTR) variants. Findings indicated that the highest number of substances were used by male students harboring low-activity MAOA alleles with a history of childhood emotional abuse. In contrast, female homozygous high-activity MAOA carriers with a history of emotional and physical abuse reported consumption of the greatest number of substances. Our results indicate that PSU among college students is influenced by the interaction of MAOA and child maltreatment in a sex-specific fashion. Further studies are warranted to understand the mechanisms of sex differences in the biosocial interplays underlying PSU in this at-risk group

The WULCA consensus characterization model for water scarcity footprints: assessing impacts of water consumption based on available water remaining (AWARE)

Purpose Life cycle assessment (LCA) has been used to assess freshwater-related impacts according to a new water footprint framework formalized in the ISO 14046 standard. To date, no consensus-based approach exists for applying this standard and results are not always comparable when different scarcity or stress indicators are used for characterization of impacts. This paper presents the outcome of a 2-year consensus building process by the Water Use in Life Cycle Assessment (WULCA), a working group of the UNEP-SETAC Life Cycle Initiative, on a water scarcity midpoint method for use in LCA and for water scarcity footprint assessments. Methods In the previous work, the question to be answered was identified and different expert workshops around the world led to three different proposals. After eliminating one proposal showing low relevance for the question to be answered, the remaining two were evaluated against four criteria: stakeholder acceptance, robustness with closed basins, main normative choice, and physical meaning. Results and discussion The recommended method, AWARE, is based on the quantification of the relative available water remaining per area once the demand of humans and aquatic ecosystems has been met, answering the question “What is the potential to deprive another user (human or ecosystem) when consuming water in this area?” The resulting characterization factor (CF) ranges between 0.1 and 100 and can be used to calculate water scarcity footprints as defined in the ISO standard. Conclusions After 8 years of development on water use impact assessment methods, and 2 years of consensus building, this method represents the state of the art of the current knowledge on how to assess potential impacts from water use in LCA, assessing both human and ecosystem users’ potential deprivation, at the midpoint level, and provides a consensus-based methodology for the calculation of a water scarcity footprint as per ISO 14046

Survival Outcomes and Effect of Early vs. Deferred cART Among HIV-Infected Patients Diagnosed at the Time of an AIDS-Defining Event: A Cohort Analysis

Objectives: We analyzed clinical progression among persons diagnosed with HIV at the time of an AIDS-defining event, and assessed the impact on outcome of timing of combined antiretroviral treatment (cART).Methods: Retrospective, European and Canadian multicohort study.. Patients were diagnosed with HIV from 1997-2004 and had clinical AIDS from 30 days before to 14 days after diagnosis. Clinical progression (new AIDS event, death) was described using Kaplan-Meier analysis stratifying by type of AIDS event. Factors associated with progression were identified with multivariable Cox regression. Progression rates were compared between those starting early (<30 days after AIDS event) or deferred (30-270 days after AIDS event) cART.Results: The median (interquartile range) CD4 count and viral load (VL) at diagnosis of the 584 patients were 42 (16, 119) cells/mu L and 5.2 (4.5, 5.7) log(10) copies/mL. Clinical progression was observed in 165 (28.3%) patients. Older age, a higher VL at diagnosis, and a diagnosis of non-Hodgkin lymphoma (NHL) (vs. other AIDS events) were independently associated with disease progression. Of 366 patients with an opportunistic infection, 178 (48.6%) received early cART. There was no significant difference in clinical progression between those initiating cART early and those deferring treatment (adjusted hazard ratio 1.32 [95% confidence interval 0.87, 2.00], p = 0.20).Conclusions: Older patients and patients with high VL or NHL at diagnosis had a worse outcome. Our data suggest that earlier initiation of cART may be beneficial among HIV-infected patients diagnosed with clinical AIDS in our setting

Estimation of renal function by CKD-EPI versus MDRD in a cohort of HIV-infected patients: a cross-sectional analysis

Background: Accurately determining renal function is essential for clinical management of HIV patients. Classically, it has been evaluated by estimating glomerular filtration rate (eGFR) with the MDRD-equation, but today there is evidence that the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation has greater diagnostic accuracy. To date, however, little information exists on patients with HIV-infection. This study aimed to evaluate eGFR by CKD-EPI vs. MDRD equations and to stratify renal function according to KDIGO guidelines. Methods: Cross-sectional, single center study including adult patients with HIV-infection. Results: Four thousand five hundred three patients with HIV-infection (864 women19%) were examined. Median age was 45 years (IQR 37-52), and median baseline creatinine was 0.93 mg/dL (IQR 0.82-1.05). A similar distribution of absolute measures of eGFR was found using both formulas (p = 0.548). Baseline median eGFR was 95.2 and 90.4 mL/min/ 1.73 m(2) for CKD-EPI and MDRD equations (p 90 mL/min/1.73 m(2)) in 73% patients and '' mild reduced GFR '' (60-89 mL/min/1.73 m(2)) in 24.3% of the patients, formerly classified as >60 mL/min/1.73 m(2) with MDRD. Conclusions: There was good correlation between CKD-EPI and MDRD. Estimating renal function using CKD-EPI equation allowed better staging of renal function and should be considered the method of choice. CKD-EPI identified a significant proportion of patients (24%) with mild reduced GFR (60-89 mL/min/1.73 m(2)).Red de SidaInstituto de Salud Carlos III, Madrid, SpainEuropean Regional Development Fund (ERDF)Univ Fed Sao Paulo, Kidney Transplant Div, Hosp Rim, Sao Paulo, BrazilUniv Barcelona, Hosp Clin IDIBAPS, Nephrol & Renal Transplantat Serv, Barcelona, SpainHosp Clin Barcelona, Biomed Diag Ctr, Core Lab, Barcelona, SpainHosp Olot, Internal Med Serv, Girona, SpainUniv Girona, Dept Med Sci, Girona, SpainUniv Barcelona, Hosp Clin IDIBAPS, Infect Dis Serv, Barcelona, SpainUniv Fed Sao Paulo, Kidney Transplant Div, Hosp Rim, Sao Paulo, BrazilRed de Sida: RD12/0017/0001Instituto de Salud Carlos III, Madrid, Spain: INT15/00168Web of Scienc

Emergy Analysis and Sustainability Efficiency Analysis of Different Crop-Based Biodiesel in Life Cycle Perspective

Biodiesel as a promising alternative energy resource has been a hot spot in chemical engineering nowadays, but there is also an argument about the sustainability of biodiesel. In order to analyze the sustainability of biodiesel production systems and select the most sustainable scenario, various kinds of crop-based biodiesel including soybean-, rapeseed-, sunflower-, jatropha-and palmbased biodiesel production options are studied by emergy analysis; soybean-based scenario is recognized as the most sustainable scenario that should be chosen for further study in China. DEA method is used to evaluate the sustainability efficiencies of these options, and the biodiesel production systems based on soybean, sunflower, and palm are considered as DEA efficient, whereas rapeseed-based and jatropha-based scenarios are needed to be improved, and the improved methods have also been specified

Effect of Maraviroc Intensification on HIV-1-Specific T Cell Immunity in Recently HIV-1-Infected Individuals

Background The effect of maraviroc on the maintenance and the function of HIV-1-specific T cell responses remains unknown. Methods Subjects recently infected with HIV-1 were randomized to receive anti-retroviral treatment with or without maraviroc intensification for 48 weeks, and were monitored up to week 60. PBMC and in vitro-expanded T cells were tested for responses to the entire HIV proteome by ELISpot analyses. Intracellular cytokine staining assays were conducted to monitor the (poly)-functionality of HIV-1-specific T cells. Analyses were performed at baseline and week 24 after treatment start, and at week 60 (3 months after maraviroc discontinuation). Results Maraviroc intensification was associated with a slower decay of virus-specific T cell responses over time compared to the non-intensified regimen in both direct ex-vivo as well as in in-vitro expanded cells. The effector function profiles of virus-specific CD8+ T cells were indistinguishable between the two arms and did not change over time between the groups. Conclusions Maraviroc did not negatively impact any of the measured parameters, but was rather associated with a prolonged maintenance of HIV-1-specific T cell responses. Maraviroc, in addition to its original effect as viral entry inhibitor, may provide an additional benefit on the maintenance of virus-specific T cells which may be especially important for future viral eradication strategies

In vivo effects of romidepsin on T-Cell activation, apoptosis and function in the BCN02 HIV-1 kick&Kill clinical trial

Romidepsin (RMD) is a well-characterized histone deacetylase inhibitor approved for the treatment of cutaneous T-cell lymphoma. in vitro and in vivo studies have demonstrated that it is able to induce HIV-1 gene expression in latently infected CD4+ T cells from HIV-1+ individuals on suppressive antiretroviral therapy. However, in vitro experiments suggested that RMD could also impair T-cell functionality, particularly of activated T cells. Thus, the usefulness of RMD in HIV-1 kick&kill strategies, that aim to enhance the immune system elimination of infected cells after inducing HIV-1 viral reactivation, may be limited. In order to address whether the in vitro observations are replicated in vivo, we determined the effects of RMD on the total and HIV-1-specific T-cell populations in longitudinal samples from the BCN02 kick&kill clinical trial (NCT02616874). BCN02 was a proof-of-concept study in 15 early treated HIV-1+ individuals that combined MVA.HIVconsv vaccination with three weekly infusions of RMD given as a latency reversing agent. Our results show that RMD induced a transient increase in the frequency of apoptotic T cells and an enhanced activation of vaccine-induced T cells. Although RMD reduced the number of vaccine-elicited T cells secreting multiple cytokines, viral suppressive capacity of CD8+ T cells was preserved over the RMD treatment. These observations have important implications for the design of effective kick&kill strategies for the HIV-1 cure