Frictional sliding without geometrical reflection symmetry

The dynamics of frictional interfaces play an important role in many physical systems spanning a broad range of scales. It is well-known that frictional interfaces separating two dissimilar materials couple interfacial slip and normal stress variations, a coupling that has major implications on their stability, failure mechanism and rupture directionality. In contrast, interfaces separating identical materials are traditionally assumed not to feature such a coupling due to symmetry considerations. We show, combining theory and experiments, that interfaces which separate bodies made of macroscopically identical materials, but lack geometrical reflection symmetry, generically feature such a coupling. We discuss two applications of this novel feature. First, we show that it accounts for a distinct, and previously unexplained, experimentally observed weakening effect in frictional cracks. Second, we demonstrate that it can destabilize frictional sliding which is otherwise stable. The emerging framework is expected to find applications in a broad range of systems.Comment: 14 pages, 5 figures + Supplementary Material. Minor change in the title, extended analysis in the second par

Liver transplantation for hepatocellular carcinoma: A proposal of a prognostic scoring system

Background: The current staging system of hepatocellular carcinoma established by the International Union Against Cancer and the American Joint Committee on Cancer does not necessarily predict the outcomes after hepatic resection or transplantation. Study Design: Various clinical and pathologic risk factors for tumor recurrence were examined on 344 consecutive patients who received hepatic transplantation in the presence of nonfibrolamellar hepatocellular carcinoma to establish a reliable risk scoring system. Results: Multivariate analysis identified three factors as independently significant poor prognosticators: 1) bilobarly distributed tumors, 2) size of the greatest tumor (2 to 5 cm and > 5 cm), and 3) vascular invasion (microscopic and macroscopic). Prognostic risk score (PRS) of each patient was calculated from the relative risks of multivariate analysis. The patients were grouped into five grades of tumor recurrence risk: grade 1: PRS = 0 to 11.0 to 15.0; grade 4: PRS ≥ 15.0; and grade 5: positive node, metastasis, or margin. The proposed PRS system correlated extremely well with tumor-free survival after liver transplantation (100%, 61%, 40%, 5%, and 0%, from grades 1 to 5, respectively, at 5 years), but current pTNM staging did not. Conclusions: 1) Patients with grades 1 and 2 are effectively treated with liver transplantation, 2) patients with grades 4 and 5 are poor candidates for liver transplantation, and 3) patients with grade 1 do not benefit from adjuvant chemotherapy. (C) 2000 by the American College of Surgeons

Pandora - INIA, Nuevo Cultivar de Trigo Harinero de Primavera Para Chile

Pandora - INIA is a spring wheat (Triticum aestivum L.) cultivar created by the Wheat Project at Quilamapu Regional Research Center of the National Agricultural Research Institute (INIA), Chill\ue1n, Chile, starting from a cross made in 1989. It is a semi-dwarf wheat with a plant height of 90 - 95 cm. The grain is brown and with an ovate shape. The spike is white and bearded. In trials its grain yield has varied between 7.5 and 10.8 t ha-1. The average bread volume, sedimentation value and grain protein were 722 cm3, 41.6 cm3, and 11.1% respectively, which classified this cultivar for direct use in bread making.Pandora - INIA es un cultivar de trigo (Triticum aestivum L.) de primavera creado por el Proyecto Trigo del Instituto de Investigaciones Agropecuarias (INIA), en el Centro Regional de Investigaci\uf3n Quilamapu, Chill\ue1n, Chile, a partir de un cruzamiento efectuado en 1989. Es un trigo semienano con una altura de planta de 90 - 95 cm. El grano es de color caf\ue9 obscuro y de forma ovada. La espiga es blanca y barbada. En experimentos su rendimiento ha variado entre 7,5 y 10,8 t ha-1. El promedio de volumen de pan, valor de sedimentaci\uf3n y prote\uedna del grano fueron, 722 cm3, 41,6 cm3, y 11,1% respectivamente, lo que clasifica este cultivar como de panificaci\uf3n directa

The continuity of the inversion and the structure of maximal subgroups in countably compact topological semigroups

In this paper we search for conditions on a countably compact (pseudo-compact) topological semigroup under which: (i) each maximal subgroup $H(e)$ in $S$ is a (closed) topological subgroup in $S$; (ii) the Clifford part $H(S)$(i.e. the union of all maximal subgroups) of the semigroup $S$ is a closed subset in $S$; (iii) the inversion $\operatorname{inv}\colon H(S)\to H(S)$ is continuous; and (iv) the projection $\pi\colon H(S)\to E(S)$, $\pi\colon x\longmapsto xx^{-1}$, onto the subset of idempotents $E(S)$ of $S$, is continuous

Bis(tetra­methyl­ammonium) tetra­chlorido­zincate(II), phase VI

Phase VI of bis­(tetra­methyl­ammonium) tetra­chloro­zincate(II), (C4H12N)2[ZnCl4], contains three formula units per asymmetric unit. Several short C—H⋯Cl contacts [2.70 (3) and 2.72 (4) Å] are observed, but they are believed to participate only in van der Waals inter­actions. The crystal studied exhibited inversion twinning

Inferring Mobility of Care Travel Behavior From Transit Origin-Destination Data

There are substantial differences in travel behavior by gender on public transit. Studies have concluded that these differences are largely attributable to household responsibilities typically falling disproportionately on women, leading to women being more likely to utilize transit for purposes referred to by the umbrella concept of "mobility of care". In contrast to past studies that have quantified the impact of gender using survey and qualitative data, we propose a novel data-driven workflow utilizing a combination of previously developed origin, destination, and transfer inference (ODX) based on individual transit fare card transactions, name-based gender inference, and geospatial analysis as a framework to identify mobility of care trip making. We apply this framework to data from the Washington Metropolitan Area Transit Authority (WMATA). Analyzing data from millions of journeys conducted in the first quarter of 2019, the results of this study show that our proposed workflow can identify mobility of care travel behavior, detecting times and places of interest where the share of women travelers in an equally-sampled subset (on basis of inferred gender) of transit users is 10% - 15% higher than that of men. The workflow presented in this study provides a blueprint for combining transit origin-destination data, inferred customer demographics, and geospatial analyses enabling public transit agencies to assess, at the fare card level, the gendered impacts of different policy and operational decisions.Comment: Updated reference formatting and discussion point

Long-term results after liver transplantation for primary hepatic epithelioid hemangioendothelioma

Background: Hepatic epithelioid hemangioendothelioma (PHEHE) is a multifocal, low-grade malignant neoplasia characterized by its epithelial-like appearance and vascular endothelial histogenesis. The outcome of 16 patients treated with orthotopic liver transplantation (OLT) is the subject of this report. Methods: A retrospective study of 16 patients with HEHE (7 men, 9 women) with ages ranging from 24 to 58 years (mean 37 ± 10.6 years). Follow-up intervals ranged from 1 to 15 years (median of 4.5 years). Results: Actual patient survival at 1, 3, and 5 years was 100, 87.5, and 71.3%, respectively. Disease-free survival at 1, 3, and 5 years was 81.3, 68.8, and 60.2%, respectively. The 90-day operative mortality was 0. Involvement of the hilar lymph nodes or vascular invasion did not affect survival. The 5-year survival of HEHE compares favorably with that of hepatocellular carcinoma at the same stage (stage 4A): 71.3 versus 9.8% (p=0.001) Conclusions: The long-term survival obtained in this series justifies OLT for these tumors even in the presence of limited extrahepatic disease. © 1995 The Society of Surgical Oncology, Inc

Características epidemiológicas y moleculares de <i>Chlamydia psittaci</i> provenientes de 8 casos humanos de psitacosis y de 4 aves relacionadas en la Argentina

In Argentina, the epidemiological and molecular characteristics of Chlamydia psittaci infections are still not sufficiently known. A total of 846 respiratory and 10 ocular samples from patients with suspected human psittacosis were tested for C. psittaci from January 2010 to March 2015. Four samples of birds related to these patients were also studied. Forty-eight samples were positive for C. psittaci by a nested PCR. The molecular characterization of twelve C. psittaci PCR-positive samples received in the National Reference Laboratory INEI-ANLIS “Dr. Carlos G. Malbrán”, Buenos Aires, Argentina was performed. Eight positive samples from humans and four from birds were genotyped by ompA gene sequencing. C. psittaci genotype A was found in all human samples and in the related birds. This report contributes to our increasing knowledge of the epidemiological and molecular characteristics of C. psittaci to conduct effective surveillance of its zoonotic infections.En la Argentina, aún no se conocen suficientemente las características epidemiológicas y moleculares de las infecciones por Chlamydia psittaci. Entre enero del 2010 y marzo del 2015 se estudiaron 846 muestras respiratorias y 10 oculares de pacientes con sospecha de psitacosis para la búsqueda de C. psittaci. También se estudiaron 4 muestras de aves relacionadas con estos pacientes. De ese total, 48 muestras fueron positivas para C. psittaci mediante una reacción en cadena de la polimerasa (PCR) anidada. Posteriormente, se realizó en el INEI-ANLIS «Dr. Carlos G. Malbrán» la caracterización molecular de 12 muestras positivas para C. psittaci, 8 de humanos y 4 de aves, que fueron genotipificadas por secuenciación del gen ompA. C. psittaci genotipo A se encontró en todas esas muestras. Este informe contribuye a mejorar nuestro conocimiento de las características epidemiológicas y moleculares de C. psittaci para lograr una vigilancia efectiva de la zoonosis que produce.Facultad de Ciencias Veterinaria

Evaluation of bactericidal activity of monoclonal antibodies obtained from Neisseria meningitidis

Introduction: Serum Bactericidal Assays (SBAs) are considered as the gold standard to evaluate the immunogenicity of many vaccine formulations against infectious agents, for example Neisseria meningitidis vaccines. SBAs are also used to evaluate vaccine lots before release to the market, because it has been demonstrated that there is a correlation between bactericidal antibody titers and protection. For Laboratory and Clinical Good Practice, it is very important to have a positive control in each assay. To our knowledge, there is no commercial positive control to serve this function, therefore the purpose of this work was to evaluate a monoclonal antibody (mAb) panel against N. meningitidis strains produced at Institute Finlay of Vaccines as a reference material in the established bactericidal assay, with the advantage of high homogeneity and specificity and relative low cost of the mAbs test agents. Materials and Methods: Specificity of a panel of mAbs was evaluated by a whole cell enzyme linked immunoassay (ELISA). The positive mAbs were then tested for bactericidal effect against target strains: F8238 (serogroup A), CU385/83 y NZ228/98 (serogroup B) and C11 (serogroup C). Determinations were carried out in triplicate and the mean was calculated. Results: In this study, we positively identified five mAbs out of seven that recognised specific, selected N. meningitidis strains. However, only three mAbs (anti-PsA, anti-P1.15 and anti-P1.4) showed bactericidal activity with their homologous strain, and this was related to the mAbs subclass. Conclusions: Three monoclonal antibodies presented bactericidal activity and they have the potential to be used as positive controls in bactericidal assays