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

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

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

Oogenesis of Helobdella ampullariae (Hirudinida, Glossiphoniidae)

El conocimiento de la gametogénesis en Hirudinida es una herramienta importante que permite interpretar el ciclo reproductor. La ovogénesis de Helobdella ampullariae se describió en base a 30 hirudíneos recolectados en la cavidad paleal de Pomacea canaliculata. Durante el proceso de ovogénesis se reconocieron siete etapas que fueron definidas considerando las transiciones nucleares de la línea germinal, las variaciones del diámetro núcleo-citoplasmático, presencia y evolución de las reservas. Se determinó que la ovogénesis es un proceso sincrónico ya que todos los ovocitos se hallan en la misma etapa de desarrollo. Durante las fases de proliferación y meiosis el cordón ovárico incrementa su volumen y los ovocitos experimentan la profase de la primera división meiótica. Durante las etapas de previtelogénesis y vitelogénesis el ovocito I incrementa su talla. La primera fase de crecimiento ovocitario se relaciona con la incorporación de componentes celulares de las células nodrizas (vitelogénesis incipiente) y la segunda con la formación de placas de vitelo (vitelogénesis avanzada). El período de post-puesta se caracteriza por la retracción de las paredes del ovisaco y por los procesos de reabsorción que afectan al cordón ovárico. El examen microanatómico permitió confirmar que la madurez sexual ocurre en el interior del molusco hospedador.Palabras clave: histología, ovario, sanguijuelas.The knowledge of the gametogenesis in Hirudinida is an important tool that allows the understanding of the reproductive cycle. Ovogenesis of Helobdella ampullariae was described based on 30 leeches collected from mantle cavity and lung of Pomacea canaliculata. By means of histological analysis, seven stages were recognized during the oogenesis process, which were defined considering nuclear transitions of germ cells, cytoplasmic-nucleus diameter variations, presence and evolution of reserves. It was determined that oogenesis is a synchronous process, since all oocytes are in the same stage of development. During the phases of proliferation and meiosis, the ovarian cord increases its volume and the oocytes undergo the prophase of the first meiotic division. During the stages of previtelogenesis and vitellogenesis, the oocyte I increases its size within the framework of the vitellogenesis process. The first phase of oocyte growth is related to the incorporation of cellular components of the nurse cells (incipient vitellogenesis) and the second with the formation of yolk plates (advanced vitellogenesis). The post-laying period is characterized by the retraction of ovisaco walls, and by the reabsorption processes that affect the ovarian cord. The microanatomic examination allowed to confirm that sexual maturity occurs inside the host mollusk.Keywords: histology, ovary, leeches