Erratum: Step energy and step interactions on the reconstructed GaAs(001) surface (Physical Review B - Condensed Matter and Materials Physics (2014) 90 (115314) DOI: 10.1103/PhysRevB.90.115314)

We report here the corrected values for the step energies and the step interactions calculated in our paper for a large set of different step configurations. We have found that one parameter, i.e., the smearing parameter governing the band occupation around the Fermi level, was not converged enough to predict the step properties with sufficient accuracy. Since the surfaces are metallic a smearing function had to be used for the state occupation around the Fermi level. We used the smearing function proposed by Marzari and Vanderbilt. We found that the parameter entering this expression is a particularly sensitive one. The previous paper used a commonly chosen value of 0.02 Ry. However, we found that a much smaller value for this parameter was necessary to obtain well converged values for the surface energies. The convergence of the smearing parameter has been carefully checked. Figure presented

Step energy and step interactions on the reconstructed GaAs(001) surface

Using ab initio total energy calculations we have studied the relation between the step atomic configuration and its properties (step energy, donor/acceptor behavior, and step interaction) on a beta(2)(2 x 4) reconstructed GaAs (001) surface. The results have been tested against the widely used elastic dipole model for the step energy and step interaction considered valid for stress-free surfaces. We have found that acceptor-behaving steps have an attractive interaction and donor-behaving steps have a repulsive interaction in contrast with the elastic dipole model which predicts always a repulsive interaction between like-oriented steps. To account for the attractive interaction we consider the electrostatic dipole interaction having the L-2 scaling with the step distance L and therefore compatible with the standard elastic model. Using a model charge distribution with localized point charges at the step based on the electron counting model we show that the electrostatic step interaction can indeed be generally attractive and of the same order of magnitude of the negative elastic dipole interaction. Our results show however that the usually employed dipole model is unable to account for the repulsive/attractive step interaction between donorlike/acceptorlike steps. Therefore, the ab initio results suggest an important electronic contribution to the step interaction, at least at the short step distances accessible to the first-principles study. Our results explain qualitatively many experimental observations and provide an explanation to the step bunching phenomenon on GaAs(001) induced by doping or by critical growth conditions as due to the stabilization of attractively interacting step structures. These ideas would lead to the development of a bottom-up surface step engineering

Cutaneous Naganishia albida (Cryptococcus albidus) infection: a case report and literature review

Naganishia albida (Cryptococcus albidus) is considered saprophytic fungi, and is rarely reported as a human pathogen. Cutaneous infections caused by non-neoformans cryptococcus are rare. We describe a case of an immunocompetent older male with cutaneous cryptococcosis caused by Naganishia albida following skin trauma, and conduct a literature review in PubMed, Lilacs, and Embase. Only six previous similar reports were found. The seven cases (including ours) were widely distributed geographically (Brazil, the US, the UK, Hungary, South Korea, and Iran), all males, and their ages varied, ranging from 14 to 86 years. Four individuals had underlying skin diseases (Sezary Syndrome, psoriasis, and skin rash without etiology) plus potentially immunosuppressive underlying conditions (diabetes mellitus, kidney transplantation, and the use of etanercept, adalimumab, and methylprednisolone). Cutaneous presentation was polymorphic, with lesions characterized as warts, ulcers, plaques, and even macules. Two patients presented disseminated disease. Serum cryptococcal antigen was negative in six patients, and diagnosis was made by fungal culture in all. There is a lack of data on optimal antifungal treatment and outcomes

Adsorption of Indium on a InAs wetting layer deposited on the GaAs(001) surface

In this work we perform a first-principles study of the adsorption properties of an In adatom deposited on 1.75 monolayers (ML) InAs, forming a wetting layer on GaAs$(001)$ with the $\alpha_2 (2\times4)$ or $\beta_2 (2\times4)$ reconstruction. The structural properties of these reconstructions have been studied: we determine the equilibrium geometry of the surfaces and their stability for various growth conditions. We have then carried out a detailed study of the potential energy surface (PES) for an In adsorbate, finding the minima and the saddle points. The main characteristics of the PES and the bonding configurations of the In adatom on the surface are analyzed by comparing with analogous studies reported in the literature, trying to extract the effects due to: (i) the compressive strain to which the InAs adlayer is subjected, (ii) the particular surface reconstruction, and (iii) the wetting layer composition. We found that, in general, stable adsorption sites are located at: (i) locations besides the As in-dimers, (ii) positions bridging two As in-dimers, (iii) between two adjacent ad-dimers (only in $\beta_2$), and (iv) locations bridging two As ad-dimers. We find also other shallower adsorption sites which are more reconstruction specific due to the lower symmetry of the $\alpha_2$ reconstruction compared to the $\beta_2$ reconstruction

A Real Time PCR strategy for the detection and quantification of Candida albicans in human blood

Candidemia is a significant cause of bloodstream infections (BSI) in nosocomial settings. The identification of species can potentially improve the quality of care and decrease human mortality. Quantitative PCR (qPCR) was evaluated for Candida albicans detection using culture suspensions containing C. albicans, spiked human blood, the cloned qPCR target fragment (ITS2 region) and the results of these assays were compared. The assays showed a good detection limit: C. albicans DNA extracted from yeast (sensitivity 0.2 CFU/µL), spiked human blood (sensitivity 10 CFU/mL), and cloned fragment of ITS2 region (sensitivity 20 target copies/µL). The efficiency of ITS2 fragment-qPCR ranged from 89.67 to 97.07, and the linearity (R2 ) of the standard curve ranged from 0.992 to 0.999. The results showed that this ITS2-qPCR has a great potential as a molecular prototype model for the development of a test to be applied in clinical practice, greatly reducing the time of candidemia diagnosis, which is extremely important in this clinical setting

Frequency and factors associated with hospital readmission after COVID-19 hospitalization: the importance of post-COVID diarrhea

Purpose: The aim of this study was to describe the incidence and risk factors for hospital readmission and infection during the months after COVID-19 hospital admission. Methods: This prospective study included adult patients who were hospitalized due to COVID-19 and had been discharged from April 2020 to August 2020. All patients had a medical evaluation with a structured questionnaire 6 to 11 months after hospital admission. The authors included only patients with confirmed COVID-19 by RT-PCR. Patients with pregnant/postpartum women, with a proven COVID-19 reinfection or incapable of answering the questionnaire were excluded. Results: A total of 822 patients completed the follow-up assessment, and 68% reported at least one recurrent symptom related to COVID-19. The most frequent symptom was myalgia (42%). Thirty-two percent of patients visited an emergency room after COVID-19 hospitalization, and 80 (10%) patients required re-hospitalization. Risk factors for hospital readmission were orotracheal intubation during COVID-19 hospitalization (p = 0.003, OR = 2.14), Charlson score (p = 0.002, OR = 1.21), congestive heart failure (p = 0.005, OR = 2.34), peripheral artery disease (p = 0.06, OR = 2.06) and persistent diarrhea after COVID-19 hospitalization discharge (p = 0.02, OR = 1.91). The main cause of hospital readmission was an infection, 43 (54%). Pneumonia was the most frequent infection (29%). Conclusions: The presence of symptoms after six months of COVID-19 diagnosis was frequent, and hospital readmission was relatively high

Prediction of intensive care admission and hospital mortality in COVID-19 patients using demographics and baseline laboratory data

Introduction: Optimized allocation of medical resources to patients with COVID-19 has been a critical concern since the onset of the pandemic. Methods: In this retrospective cohort study, the authors used data from a Brazilian tertiary university hospital to explore predictors of Intensive Care Unit (ICU) admission and hospital mortality in patients admitted for COVID-19. Our primary aim was to create and validate prediction scores for use in hospitals and emergency departments to aid clinical decisions and resource allocation. Results: The study cohort included 3,022 participants, of whom 2,485 were admitted to the ICU; 1968 survived, and 1054 died in the hospital. From the complete cohort, 1,496 patients were randomly assigned to the derivation sample and 1,526 to the validation sample. The final scores included age, comorbidities, and baseline laboratory data. The areas under the receiver operating characteristic curves were very similar for the derivation and validation samples. Scores for ICU admission had a 75% accuracy in the validation sample, whereas scores for death had a 77% accuracy in the validation sample. The authors found that including baseline flu-like symptoms in the scores added no significant benefit to their accuracy. Furthermore, our scores were more accurate than the previously published NEWS-2 and 4C Mortality Scores. Discussion and conclusions: The authors developed and validated prognostic scores that use readily available clinical and laboratory information to predict ICU admission and mortality in COVID-19. These scores can become valuable tools to support clinical decisions and improve the allocation of limited health resources

High prevalence of HIV-associated neurocognitive disorders (HAND) in São Paulo City, Brazil

Introduction: HIV-associated neurocognitive disorders (HAND) are the subject of many studies, some of them reporting a prevalence of up to 50 percent. Objectives: To determine the prevalence and factors associated with HIV neurocognitive disorders (HAND) in a cohort of HIV-1-infected patients in São Paulo city, Brazil. Methodology: Descriptive cross-sectional study including 106 HIV-1-infected patients, employing direct interview and neuropsychological tests, applied by trained neuro-psychologists with expertise in the tests. Other, similar assessment tools we used were Brief Neurocognitive Questionnaire, International HIV Dementia Scale, Lawton Instrumental Activities of Daily Living, Hospital Anxiety and Depression Scale, Social Support Scale for People with HIV/Aids, Assessment of Adherence to Antiretroviral Therapy Questionnaire, and a complex neuropsychological assessment. Results: We included 106 patients from May 2015 to April 2018. We found a high prevalence of HAND in our patients (45%), with 27.5% presenting asymptomatic neurological impairment (ANI) and 17.5% mild neurological dysfunction (MND); only one patient presented HIV-associated dementia (HAD) (0.9%). Women were more likely to have MND (52.9%) and the only case of HAD was also female. The high prevalence of neurocognitive disorders was independent of the immunological status, use of efavirenz, or virological control. Conclusions: This study may mirror the national and international scenarios, showing a high prevalence of HAND (45%) and the prevalence of some risk factors, in special among women

Fighting HIV/AIDS in a developing country: lessons from a small cohort from the largest Brazilian city

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Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery