Frictional Duality Observed during Nanoparticle Sliding

One of the most fundamental questions in tribology concerns the area dependence of friction at the nanoscale. Here, experiments are presented where the frictional resistance of nanoparticles is measured by pushing them with the tip of an atomic force microscope. We find two coexisting frictional states: While some particles show finite friction increasing linearly with the interface areas of up to 310,000nm^2, other particles assume a state of frictionless sliding. The results further suggest a link between the degree of surface contamination and the occurrence of this duality.Comment: revised versio

Softwares de gestão na indústria: uma experiência de implantação ERP

TCC (graduação) - Universidade Federal de Santa Catarina, Centro Sócio Econômico, Administração.O objetivo deste artigo é compreender os obstáculos que dificultam a implementação de softwares de gestão em empresas industriais. O ambiente de aplicação do estudo é uma empresa de medição e instrumentação denominada Conaut. A empresa adotou um software de gestão (ERP Microsiga) em 2015, e desde então encontra dificuldade em adaptar-se às práticas que o sistema exige. A partir de uma metodologia descritiva, pretende-se analisar hipóteses com a aplicação de um questionário, observação e levantamento de estudos similares. Deste modo, determinou que existe relação entre o nível de especificidade técnica exigido pelo projeto e a necessidade de envolvimento dos colaboradores da Conaut

Einen neuen Anfang machen: zur Genese des Moskauer Vertrags, 1966-1970

Der Moskauer Vertrag von 1970 gilt als einer der wichtigsten Verträge der Nachkriegsgeschichte. Durch ihn verständigten sich die Bundesrepublik Deutschland und die Sowjetunion darauf, zukünftige Konflikte friedlich zu lösen und die europäischen Grenzen als unverletzlich anzuerkennen. Auf diese Weise markierte das Abkommen die Grundlage für die weiteren Ostverträge. Kürzlich veröffentlichte Archivalien ermöglichen nun einen neuartigen Blick auf die Genese des Moskauer Vertrags und die damit zusammenhängende neue sowjetische Westpolitik, die in der bisherigen Forschung oft vernachlässigt wurde

Recurrent parvovirus B19 viremia resulting in two episodes of hemophagocytic lymphohistiocytosis

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory condition with uncontrolled activation of lymphocytes and macrophages. Besides a primary (genetic) form, HLH can also be triggered by malignant, autoimmune and infectious diseases. HLH recurrences are rarely described, usually only in primary HLH. Parvovirus B19 (PVB19) Infection is one of the rare and rather benign causes of HLH. Since the infection usually results in long-lasting immunity, recurrent viremia is very uncommon. CASE PRESENTATION: We report an unusual case of a young female with recurrent PVB19 infection that led to repeated episodes of HLH. The first episode occurred at the age of 25 years with a three-week history of high fever and nonspecific accompanying symptoms. The diagnosis of HLH was confirmed by HLH-2004 criteria and HScore, PVB19 viremia was detected as underlying cause. Following guideline-based therapy, the patient was symptom-free for one year, before similar symptoms recurred in a milder form. Again, PVB19 was detected and HLH was diagnosed according to HScore. After successful treatment and a nine-month symptom-free interval, a third phase of hyperinflammation with low PVB19 viremia occurred; this time, treatment with a corticosteroid and intravenous immunoglobulin was initiated before the presence of clear diagnostic criteria for HLH. No further events occurred in the following three years. CONCLUSIONS: In the case of our patient, the recurrent viremia triggered three episodes of hyperinflammation, two of which were clearly diagnosed as HLH. To our knowledge, this is the first published case of recurrent HLH due to PVB19 infection. Therefore, the case gives new insights in triggering mechanisms for HLH

Prevalence of H. pylori among asymptomatic HIV-positive and negative individuals in Central Ethiopia and efficacy of eradication therapy

OBJECTIVES: Helicobacter pylori is a widespread pathogen and major contributor to dyspeptic disease and gastric cancer. Although the interaction between HIV and H. pylori infection is not well investigated, previous studies have suggested a decreased prevalence of H. pylori and limited efficacy of eradication therapy in HIV-positive individuals. Therefore, the objectives of this study were to describe the prevalence of H. pylori infection according to HIV status and analyze the efficacy of eradication therapy in Ethiopia. METHODS: A prospective, randomized, interventional study was performed involving HIV-positive and negative participants presenting to the Asella Referral and Teaching Hospital in Central Ethiopia between March and June 2017. A stool antigen test was used as a screening tool for H. pylori infection. Randomly selected patients received triple eradication therapy. RESULTS: The cumulative H. pylori prevalence was 77.3% (392/507): 78.8% (241/306) among HIV-positive individuals versus 75.1% (151/201) among HIV-negative individuals (P = 0.386). Twenty-five HIV-positive and 26 HIV-negative H. pylori-infected participants were randomized to receive standard triple therapy; three of them were lost to follow-up (one HIV-positive, two HIV-negative). The total eradication rate was 50.0%: 62.5% (15/24) among those HIV-negative versus 37.5% (9/24) among those HIV-positive [Au?1]. CONCLUSIONS: A high prevalence of H. pylori was observed among HIV-positive and negative individuals in Central Ethiopia. The efficacy of eradication therapy was low, with a trend towards lower efficacy in HIV-infected individuals

The Protostellar Luminosity Function

The protostellar luminosity function (PLF) is the present-day luminosity function of the protostars in a region of star formation. It is determined using the protostellar mass function (PMF) in combination with a stellar evolutionary model that provides the luminosity as a function of instantaneous and final stellar mass. As in McKee & Offner (2010), we consider three main accretion models: the Isothermal Sphere model, the Turbulent Core model, and an approximation of the Competitive Accretion model. We also consider the effect of an accretion rate that tapers off linearly in time and an accelerating star formation rate. For each model, we characterize the luminosity distribution using the mean, median, maximum, ratio of the median to the mean, standard deviation of the logarithm of the luminosity, and the fraction of very low luminosity objects. We compare the models with bolometric luminosities observed in local star forming regions and find that models with an approximately constant accretion time, such as the Turbulent Core and Competitive Accretion models, appear to agree better with observation than those with a constant accretion rate, such as the Isothermal Sphere model. We show that observations of the mean protostellar luminosity in these nearby regions of low-mass star formation suggest a mean star formation time of 0.3$\pm$0.1 Myr. Such a timescale, together with some accretion that occurs non-radiatively and some that occurs in high-accretion, episodic bursts, resolves the classical "luminosity problem" in low-mass star formation, in which observed protostellar luminosities are significantly less than predicted. An accelerating star formation rate is one possible way of reconciling the observed star formation time and mean luminosity.Comment: 22 pages, 9 figures, accepted to Ap

Risk-adjusted active tuberculosis case finding strategy in central Ethiopia

BACKGROUND: The World Health Organization recommends active case finding for tuberculosis (TB). Our study evaluated the targeted screening of household contacts (HHCs) of patients with contagious pulmonary tuberculosis (PTB) in Central Ethiopia. METHODS: The HHCs of patients with microbiologically confirmed PTB were screened for TB symptoms and risk factors for TB transmission. Symptomatic HHCs were subjected to secondary investigation. Antimicrobial resistance was investigated among study participants. RESULTS: Overall, 112 index patients with TB were included, and 289 HHCs from 89 households were screened. Multidrug-resistant-TB was detected in 2.7% (n=3) of index patients. The routine public health system process did not identify any TB suspects among HHCs. In total, 23.9% (n=69) of HHCs reported ≥1 TB symptom and PTB was confirmed in 2.1% (n=6). Reporting >1 TB symptom (relative risk [RR] 29.4, 95% CI 3.5−245.5, P<0.001) and night sweats (RR 27.1, 95% CI 3.2−226.6, P<0.001) were associated with the greatest relative risk. Regular alcohol consumption was identified as an individual risk factor for TB among HHCs (P=0.022). CONCLUSION: The MDR-TB rate among our patients was higher than recently reported for Ethiopia. Enhanced contact tracing using a risk-adjusted approach seems feasible and increases the case detection rate among HHCs of confirmed TB cases

Prevalence and characterization of antimicrobial resistance among gram-negative bacteria isolated from febrile hospitalized patients in central Ethiopia

BACKGROUND: Infectious diseases are among the leading causes of death in many low-income countries, such as Ethiopia. Without reliable local data concerning causative pathogens and antimicrobial resistance, empiric treatment is suboptimal. The objective of this study was to characterize gram-negative bacteria (GNB) as pathogens and their resistance pattern in hospitalized patients with infections in central Ethiopia. METHODS: Patients ≥ 1 year of age with fever admitted to the Asella Referral and Teaching Hospital from April 2016 to June 2018 were included. Blood and other appropriate clinical specimens were collected and cultured on appropriate media. Antibiotic susceptibility testing (AST) was performed using the Kirby–Bauer method and VITEK® 2. Species identification and detection of resistance genes were conducted using MALDI-ToF MS (VITEK® MS) and PCR, respectively. RESULTS: Among the 684 study participants, 54.2% were male, and the median age was 22.0 (IQR: 14–35) years. Blood cultures were positive in 5.4% (n = 37) of cases. Among other clinical samples, 60.6% (20/33), 20.8% (5/24), and 37.5% (3/8) of swabs/pus, urine and other body fluid cultures, respectively, were positive. Among 66 pathogenic isolates, 57.6% (n = 38) were GNB, 39.4% (n = 26) were gram-positive, and 3.0% (n = 2) were Candida species. Among the isolated GNB, 42.1% (16/38) were Escherichia coli, 23.7% (9/38) Klebsiella pneumoniae and 10.5% (4/38) Pseudomonas aeruginosa. In total, 27/38 gram-negative isolates were available for further analysis. Resistance rates were as follows: ampicillin/sulbactam, 92.6% (n = 25); cefotaxime, 88.9% (n = 24); ceftazidime, 74.1% (n = 20); cefepime, 74.1% (n = 20); gentamicin, 55.6% (n = 15); piperacillin/tazobactam, 48.1% (n = 13); meropenem, 7.4% (n = 2); and amikacin, 3.7% (n = 1). The bla(NDM-1) gene was detected in one K. pneumoniae and one Acinetobacter baumannii isolate, which carried an additional bla(OXA-51) gene. The ESBL enzymes were detected in 81.5% (n = 22) of isolates as follows: TEM, 77.2% (n = 17); CTX-M-1 group, 68.2% (n = 15); SHV group, 27.3% (n = 6); and CTX-M-9 group, 9.1% (n = 2). Based on the in vitro antimicrobial susceptibility results, empiric treatment initiated in 13 of 18 (72.2%) patients was likely ineffective. CONCLUSION: We report a high prevalence of ESBL-producing bacteria (81.5%) and carbapenem resistance (7.4%), with more than half of GNB carrying two or more ESBL enzymes resulting in suboptimal empiric antibiotic therapy. These findings indicate a need for local and national antimicrobial resistance surveillance and the strengthening of antimicrobial stewardship programs