886 research outputs found
Halogen-bonded architectures of multivalent calix[4]arenes
A small family of novel halogen-bonded crystalline supramolecular architectures of calixarenes was obtained by the co-crystallization of cone (1) and 1,3-alternate tetrakis(3-iodopropargyloxy)calix[4]arene (4) as tetradentate halogen donors with different multidentate acceptors. Particularly interesting is the interpenetrated diamondoid network of 4 with DABCO, which represents the first example of a 2D network of calixarene macrocycles where halogen bonding is the key interaction for self-organization
Dynamics and energy spectra of aperiodic discrete-time quantum walks
We investigate the role of different aperiodic sequences in the dynamics of single quantum particles in discrete space and time. For this we consider three aperiodic sequences, namely, the Fibonacci, Thue-Morse, and Rudin-Shapiro sequences, as examples of tilings the diffraction spectra of which have pure point, singular continuous, and absolutely continuous support, respectively. Our interest is to understand how the order, intrinsically introduced by the deterministic rule used to generate the aperiodic sequences, is reflected in the dynamical properties of the quantum system. For this system we consider a single particle undergoing a discrete-time quantum walk (DTQW), where the aperiodic sequences are used to distribute the coin operations at different lattice positions (inhomogeneous DTQW) or by applying the same coin operation at all lattice sites at a given time but choosing different coin operation at each time step according to the chosen aperiodic sequence (time dependent DTQW). We study the energy spectra and the spreading of an initially localized wave packet for different cases, finding that in the case of Fibonacci and Thue-Morse tilings the system is superdiffusive, whereas in the Rudin-Shapiro case it is strongly subdiffusive. Trying to understand this behavior in terms of the energy spectra, we look at the survival amplitude as a function of time. By means of the echo we present strong evidence that, although the three orderings are very different as evidenced by their diffraction spectra, the energy spectra are all singular continuous except for the inhomogeneous DTQW with the Rudin-Shapiro sequence where it is discrete. This is in agreement with the observed strong localization both in real space and in the Hilbert space. Our paper is particularly interesting because quantum walks can be engineered in laboratories by means of ultracold gases or in optical waveguides, and therefore would be a perfect playground to study singular continuous energy spectra in a completely controlled quantum setup
Histological and mutational profile of diffuse gastric cancer: current knowledge and future challenges
Gastric cancer (GC) pathogenesis is complex and heterogeneous, reflecting morphological, molecular and genetic diversity. Diffuse gastric cancer (DGC) and intestinal gastric cancer (IGC) are the major histological types. GC may be sporadic or hereditary; sporadic GC is related to environmental and genetic low-risk factors and hereditary GC is caused by inherited high-risk mutations, so far identified only for the diffuse histotype. DGC phenotypic heterogeneity challenges the current understanding of molecular mechanisms underlying carcinogenesis. The definition of a DGC-specific mutational profile remains controversial, possibly reflecting the heterogeneity of DGC-related histological subtypes [signet-ring cell carcinoma (SRCC) and poorly cohesive carcinoma not otherwise specified (PCC-NOS)]. Indeed, DGC and DGC-related subtypes may present specific mutational profiles underlying the particularly aggressive behaviour and dismal prognosis of DGC vs IGC and PCC-NOS vs SRCC. In this systematic review, we revised the histological presentations, molecular classifications and approved therapies for gastric cancer, with a focus on DGC. We then analysed results from the most relevant studies, reporting mutational analysis data specifying mutational frequencies, and their relationship with DGC and IGC histological types, and with specific DGC subtypes (SRCC and PCC-NOS). We aimed at identifying histology-associated mutational profiles with an emphasis in DGC and its subtypes (DGC vs IGC; sporadic vs hereditary DGC; and SRCC vs PCC-NOS). We further used these mutational profiles to identify the most commonly affected molecular pathways and biological functions, and explored the clinical trials directed specifically to patients with DGC. This systematic analysis is expected to expose a DGC-specific molecular profile and shed light into potential targets for therapeutic intervention, which are currently missing.The authors acknowledge the support of the National Infrastructure ‘GenomePT’ – National Laboratory for Genome Sequencing and Analysis (POCI-01-0145-FEDER-022184). J.G-P acknowledges the support of Faculty of Medicine from University of Porto, specifically by the Doctoral Programme in Biomedicine and the Solve-RD Project (H2020-SC1-2017-Single-Stage-RTD) for his PhD fellowship. R.B-M. acknowledges the support of Institute of Biomedical Sciences Abel Salazar from University of Porto, specifically by the Doctoral Programme BiotechHealth and the FCT – Fundação para a Ciência e a Tecnologia for her PhD fellowship (ref. SFRH/BD/145132/2019). This research and its authors were funded by FEDER – Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 – Operacional Programme for Competitiveness and Internationalization (POCI), Portugal 2020, and by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project ‘Institute for Research and Innovation in Health Sciences’ (POCI-01-0145-FEDER-007274). This work was also financed by the projects NORTE-01-0145-FEDER-000003 (DOCnet) and NORTE-01-0145-FEDER-000029 (CANCER) – supported by Norte Portugal Regional Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) – project POCI-01-0145-FEDER-016390 (CancelStem) and PTDC/BTM-TEC/30164/2017 (3DChroMe), funded by ERDF, POCI and FCT
The psychological impact of COVID-19 on people suffering from dysfunctional eating behaviours: A linguistic analysis of the contents shared in an online community during the lockdown
The coronavirus disease 2019 (COVID-19) spread several months ago from China and it is now a global pandemic. The experience of lockdown has been an undesirable condition for people with mental health problems, including eating disorders. The present study has the aim of understanding the impact of the first wave of the COVID-19 pandemic on people with selfreported disordered eating behaviours. A linguistic analysis was carried out with regard to the online posts and comments published by 1971 individuals (86% women) in a Facebook online community focusing on EDs during the lockdown. A total of 244 posts and 3603 comments were collected during the 56 days of lockdown (from the 10th of March until the 4th of May 2020) in Italy and were analysed by Linguistic Inquiry and Word Count (LIWC) software. The results showed that words related to peer support decreased in posts over time, and that anxiety and anger increased in the published comments. Moreover, greater feelings of negativity and anxiety were found in posts and comments throughout the COVID-19 pandemic, as well as lesser use of words related to positive emotions. Thematic qualitative analysis revealed eight themes that described the main subjective components of ED symptomatology and distress during the first COVID-19 lockdown. The current findings can help in delivering tailored treatments to people with eating disorders during the COVID-19 pandemic
Controle químico de plantas daninhas, com aplicações em pré e pós-emergência, na cultura da soja (glycine max).
Laparoscopic treatment of a large pedunculated hemangioma of the liver: A case report
Hepatic hemangiomas are the most common benign tumors of the liver, often asymptomatic and discovered incidentally. A 62-year-old woman was referred to our Institution under the suspicion of having an 8 cm-sized GIST. Due to the atypical features of the lesion on TC scan, a biopsy was performed. We report the case of pedunculated hepatic hemangioma with the aim to discuss the diagnostic approach, the possible causes of misdiagnosis and the opportunity of the laparoscopic approach
Ovary microanatomy and oogenesis of amphipod Hyalella curvispina Shoemaker 1942
El conocimiento de la gametogénesis en crustáceos permite diferenciar los estadios de desarrollo durante el ciclo reproductor e interpretar aspectos de su dinámica poblacional. Se realizó el estudio microanatómico del ovario y la ovogénesis del anfípodo dulceacuícola Hyalella curvispina. Los crustáceos fueron recolectados en el Arroyo Rivera (Saldungaray, provincia de Buenos Aires, Argentina). Se describieron los tipos celulares del ovario y se caracterizaron microscópicamente las células germinales (ovogonias, ovocitos en previtelogénesis, vitelogénesis incipiente y avanzada) y sus modificaciones a lo largo de la ovogénesis. El ovario se caracteriza por presentar una zonación intraovárica debido a que los elementos germinales se desarrollan en bandas longitudinales superpuestas. La ovogénesis comprende cuatro etapas: meiosis, previtelogénesis, vitelogénesis primaria y secundaria. Durante la vitelogénesis el ovocito I incrementa su talla nuclear y citoplasmática como producto de la síntesis y acumulación de las reservas. El vitelo resultante de la vitelogénesis primaria es endógeno. El marcado incremento en las tallas ovocitarias es concomitante con la aparición de las células foliculares, las que desempeñan un papel preponderante durante la vitelogénesis secundaria (exógena).Palabras clave: histología, gónada, Amphipoda, agua dulce.The knowledge of gametogenesis in crustaceans allows to differentiate the stages of development during the reproductive cycle and to interpret aspects of its population dynamics. A microanatomical study of the ovary and oogenesis of the freshwater amphipod Hyalella curvispina was performed. The crustaceans were collected in Arroyo Rivera (Saldungaray, Buenos Aires Province, Argentina). Ovarian cell types were described and germ cells (oogonies, oocytes in previtelogenesis, incipient and advanced vitellogenesis) and their modifications throughout oogenesis were characterized microscopically. The ovary is characterized by an intraovarian zonation because the germinal elements develop in superimposed longitudinal bands. Oogenesis comprises four stages: meiosis, previtellogenesis, primary and secondary vitellogenesis. During vitellogenesis, the oocyte I increases its nuclear and cytoplasmic size as a product of the synthesis and accumulation of the reserves. The yolk resulting from primary vitellogenesis is endogenous. The marked increase in oocyte sizes is concomitant with the appearance of follicular cells, which play a preponderant role during secondary (exogenous) vitellogenesis.Keywords: histology, gonad, Amphipoda, freshwater
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