219 research outputs found
Depth-Sensing Indentation on REBa2Cu3O(7-\delta) Single Crystals obtained from Xenotime Mineral
A natural mixture of heavy rare earths oxides extracted from xenotime mineral
have been used to prepare large single crystals of high-temperature
REBa2Cu3O(7-\delta) superconductor grown using the CuO-BaO self-flux method.
Its mechanical properties along the ab-plane were characterized using
instrumented indentation. Hardness and elastic modulus were obtained by the
Oliver and Pharr method and corresponds to 7.4 \pm 0.2 GPa and in range 135-175
GPa at small depths, respectively. Increasing the load promotes the nucleation
of lateral cracks that causes a decrease in hardness and the measured elastic
modulus by instrumented indentation at higher loads. The indentation fracture
toughness was estimated by measuring the radial crack length from cube-corner
indentations at various loads and was 0.8 \pm 0.2 MPa.m1/2. The observed slip
systems of REBa2Cu3O(7-\delta) single crystals were [100](001) and [010](001),
the same as for YBa2Cu3O(7-\delta) single crystals. The initial stages of
deformation and fracture in the indentation process were investigated. The
hardness and elastic modulus were not strongly modified by the crystallographic
orientation in the ab-plane. This was interpreted in terms of the resolved
shear stresses in the active slip systems. Evidence of cracking along the {100}
and {110} planes on the ab-plane was observed. As a conclusion, the mechanical
properties of REBa2Cu3O(7-\delta) single crystals prepared from xenotime are
equivalent to those of YBa2Cu3O(7-\delta) single crystals produced by
conventional rare earths oxides.Comment: The paper will appear in Volume 42 (2012) of the Brazilian Journal of
Physic
"Open Innovation" and "Triple Helix" Models of Innovation: Can Synergy in Innovation Systems Be Measured?
The model of "Open Innovations" (OI) can be compared with the "Triple Helix
of University-Industry-Government Relations" (TH) as attempts to find surplus
value in bringing industrial innovation closer to public R&D. Whereas the firm
is central in the model of OI, the TH adds multi-centeredness: in addition to
firms, universities and (e.g., regional) governments can take leading roles in
innovation eco-systems. In addition to the (transversal) technology transfer at
each moment of time, one can focus on the dynamics in the feedback loops. Under
specifiable conditions, feedback loops can be turned into feedforward ones that
drive innovation eco-systems towards self-organization and the auto-catalytic
generation of new options. The generation of options can be more important than
historical realizations ("best practices") for the longer-term viability of
knowledge-based innovation systems. A system without sufficient options, for
example, is locked-in. The generation of redundancy -- the Triple Helix
indicator -- can be used as a measure of unrealized but technologically
feasible options given a historical configuration. Different coordination
mechanisms (markets, policies, knowledge) provide different perspectives on the
same information and thus generate redundancy. Increased redundancy not only
stimulates innovation in an eco-system by reducing the prevailing uncertainty;
it also enhances the synergy in and innovativeness of an innovation system.Comment: Journal of Open Innovations: Technology, Market and Complexity, 2(1)
(2016) 1-12; doi:10.1186/s40852-016-0039-
"Meaning" as a sociological concept: A review of the modeling, mapping, and simulation of the communication of knowledge and meaning
The development of discursive knowledge presumes the communication of meaning
as analytically different from the communication of information. Knowledge can
then be considered as a meaning which makes a difference. Whereas the
communication of information is studied in the information sciences and
scientometrics, the communication of meaning has been central to Luhmann's
attempts to make the theory of autopoiesis relevant for sociology. Analytical
techniques such as semantic maps and the simulation of anticipatory systems
enable us to operationalize the distinctions which Luhmann proposed as relevant
to the elaboration of Husserl's "horizons of meaning" in empirical research:
interactions among communications, the organization of meaning in
instantiations, and the self-organization of interhuman communication in terms
of symbolically generalized media such as truth, love, and power. Horizons of
meaning, however, remain uncertain orders of expectations, and one should
caution against reification from the meta-biological perspective of systems
theory
Matched-pair analysis of patients with female and male breast cancer: a comparative analysis
<p>Abstract</p> <p>Background</p> <p>Male breast cancer (MBC) is a rare disease accounting for approximately 1% of all breast carcinomas. Presently treatment recommendations are derived from the standards for female breast cancer. However, those approaches might be inadequate because of distinct gender specific differences in tumor biology of breast cancer. This study was planned in order to contrast potential differences between female and male breast cancer in both tumor biological behavior and clinical management.</p> <p>Methods</p> <p>MBC diagnosed between 1995-2007 (region Chemnitz/Zwickau, Saxony, Germany) was retrospectively analyzed. Tumor characteristics, treatment and follow-up of the patients were documented. In order to highlight potential differences each MBC was matched with a female counterpart (FBC) that showed accordance in at least eight tumor characteristics (year of diagnosis, age, tumor stage, nodal status, grade, estrogen- and progesterone receptors, HER2 status).</p> <p>Results</p> <p>108 male/female matched-pairs were available for survival analyses. In our study men and women with breast cancer had similar disease-free (DFS) and overall (OS) survival. The 5-years DFS was 53.4% (95% CI, range 54.1-66.3) in men respectively 62.6% (95% CI, 63.5-75.3) in women (p > 0.05). The 5-years OS was 71.4% (95% CI, 62.1-72.7%) and 70.3% (95% CI, 32.6-49.6) in women (p > 0.05). In males DFS analyses revealed progesterone receptor expression as the only prognostic relevant factor (p = 0.006). In multivariate analyses for OS both advanced tumor size (p = 0.01) and a lack of progesterone receptor expression were correlated (p = 0.01) with poor patients outcome in MBC.</p> <p>Conclusion</p> <p>Our comparative study revealed no survival differences between male and female breast cancer patients and gives evidence that gender is no predictor for survival in breast cancer. This was shown despite of significant gender specific differences in terms of frequency and intensity of systemic therapy in favor to female breast cancer.</p
A comparative study of mechanical and tribological properties of AISI-304 and AISI-316 submitted to glow discharge nitriding
Increased Expression of the Auxiliary β(2)-subunit of Ventricular L-type Ca(2+) Channels Leads to Single-Channel Activity Characteristic of Heart Failure
BACKGROUND: Increased activity of single ventricular L-type Ca(2+)-channels (L-VDCC) is a hallmark in human heart failure. Recent findings suggest differential modulation by several auxiliary β-subunits as a possible explanation. METHODS AND RESULTS: By molecular and functional analyses of human and murine ventricles, we find that enhanced L-VDCC activity is accompanied by altered expression pattern of auxiliary L-VDCC β-subunit gene products. In HEK293-cells we show differential modulation of single L-VDCC activity by coexpression of several human cardiac β-subunits: Unlike β(1) or β(3) isoforms, β(2a) and β(2b) induce a high-activity channel behavior typical of failing myocytes. In accordance, β(2)-subunit mRNA and protein are up-regulated in failing human myocardium. In a model of heart failure we find that mice overexpressing the human cardiac Ca(V)1.2 also reveal increased single-channel activity and sarcolemmal β(2) expression when entering into the maladaptive stage of heart failure. Interestingly, these animals, when still young and non-failing (“Adaptive Phase”), reveal the opposite phenotype, viz : reduced single-channel activity accompanied by lowered β(2) expression. Additional evidence for the cause-effect relationship between β(2)-subunit expression and single L-VDCC activity is provided by newly engineered, double-transgenic mice bearing both constitutive Ca(V)1.2 and inducible β(2) cardiac overexpression. Here in non-failing hearts induction of β(2)-subunit overexpression mimicked the increase of single L-VDCC activity observed in murine and human chronic heart failure. CONCLUSIONS: Our study presents evidence of the pathobiochemical relevance of β(2)-subunits for the electrophysiological phenotype of cardiac L-VDCC and thus provides an explanation for the single L-VDCC gating observed in human and murine heart failure
The D4Z4 Macrosatellite Repeat Acts as a CTCF and A-Type Lamins-Dependent Insulator in Facio-Scapulo-Humeral Dystrophy
Both genetic and epigenetic alterations contribute to Facio-Scapulo-Humeral Dystrophy (FSHD), which is linked to the shortening of the array of D4Z4 repeats at the 4q35 locus. The consequence of this rearrangement remains enigmatic, but deletion of this 3.3-kb macrosatellite element might affect the expression of the FSHD-associated gene(s) through position effect mechanisms. We investigated this hypothesis by creating a large collection of constructs carrying 1 to >11 D4Z4 repeats integrated into the human genome, either at random sites or proximal to a telomere, mimicking thereby the organization of the 4q35 locus. We show that D4Z4 acts as an insulator that interferes with enhancer–promoter communication and protects transgenes from position effect. This last property depends on both CTCF and A-type Lamins. We further demonstrate that both anti-silencing activity of D4Z4 and CTCF binding are lost upon multimerization of the repeat in cells from FSHD patients compared to control myoblasts from healthy individuals, suggesting that FSHD corresponds to a gain-of-function of CTCF at the residual D4Z4 repeats. We propose that contraction of the D4Z4 array contributes to FSHD physio-pathology by acting as a CTCF-dependent insulator in patients
Comportamentos agressivos em crianças e adolescentes com risco para esquizofrenia: diferenças entre gêneros
OBJECTIVE: This study aimed to investigate whether differences in aggression-related behavioral problems occur between boys and girls at high risk for schizophrenia living in the city of São Paulo, Brazil. METHOD: Using the Child Behavior Checklist, we compared the prevalence of behavioral problems between genders for the offspring (6-18 years) of mothers with diagnosis of schizophrenia and a comparison group of children born to women with no severe mental disorders recruited at the gynecology outpatient clinic of the same hospital. The Structured Clinical Interview for DSM-IV Axis I Disorders, Patient Edition was applied for the evaluation of diagnostic status of mothers. RESULTS: Male children of women with schizophrenia had a lower prevalence of aggressive behavior compared to females (4% vs. 36%; p = 0.005), whereas no gender differences regarding aggression were detected in the comparison group (24% vs. 32%; p = 0.53). Logistic regression analyses showed that male gender and being a child of women with schizophrenia interacted so as to favor lower prevalence of aggressive behavior (p = 0.03). CONCLUSION: These findings reinforce the notion that behavioral gender differences related to schizophrenia are already detectable in childhood.OBJETIVO: Investigar diferenças da ocorrência de comportamentos agressivos entre crianças e adolescentes do sexo masculino e feminino com risco genético para desenvolver esquizofrenia. MÉTODO: A prevalência de comportamentos agressivos foi medida utilizando o inventário de comportamentos para crianças e adolescentes, Child Behavior Checklist, e comparada entre os gêneros para o grupo de crianças filhas de mulheres com esquizofrenia e para um grupo de crianças filhas de mulheres atendidas no serviço de ginecologia do mesmo hospital. A entrevista clínica estruturada para DSM-IV (The Structured Clinical Interview for DSM-IV Axis I Disorders Patient Edition) foi utilizada para confirmar o diagnóstico materno. RESULTADOS: Os filhos de mulheres com esquizofrenia do sexo masculino apresentaram prevalência menor de comportamentos agressivos quando comparados às meninas (4% x 36%; p = 0,005), o que não ocorreu para o grupo comparativo (24% x 32%; p = 0,53). A análise de regressão logística mostrou que pertencer ao sexo masculino e ser filho de mulher com esquizofrenia interagiram de forma a favorecer menor prevalência de comportamentos agressivos (p = 0,03). CONCLUSÃO: Esses achados corroboram para a noção que as diferenças comportamentais entre os gêneros na esquizofrenia podem ser detectadas precocemente durante a infância
Scanpath analysis of expertise and culture in teacher gaze in real-world classrooms
Humans are born to learn by understanding where adults look. This is likely to extend into the classroom, making teacher gaze an important topic for study. Expert teacher gaze has mainly been investigated in the laboratory, and has focused mostly on one cognitive process: teacher attentional (i.e., information-seeking) gaze. No known research has made direct cultural comparisons of teacher gaze or successfully found expert–novice differences outside Western settings. Accordingly, we conducted a real-world study of expert teacher gaze across two cultural settings, exploring communicative (i.e., information-giving) as well as attentional gaze. Forty secondary school teachers wore eye-tracking glasses, with 20 teachers (10 expert; 10 novice) from the UK and 20 teachers (10 expert; 10 novice) from Hong Kong. We used a novel eye-tracking scanpath analysis to ascertain the importance of expertise and culture, individually and as a combination. Attentional teacher scanpaths were significantly more similar within than across expertise and expertise + culture sub-groups; communicative scanpaths were significantly more similar within than across expertise and culture. Detailed analysis suggests that (1) expert teachers refer back to students constantly through focused gaze during both attentional and communicative gaze and that (2) expert teachers in Hong Kong scan students more than experts do in the UK
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