452 research outputs found

    Measurement of the current-phase relation of superconducting atomic contacts

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    We have probed the current-phase relation of an atomic contact placed with a tunnel junction in a small superconducting loop. The measurements are in quantitative agreement with the predictions of a resistively shunted SQUID model in which the Josephson coupling of the contact is calculated using the independently determined transmissions of its conduction channels.Comment: to be published in Physical Review Letter

    Relevance of terpenoids on flammability of Mediterranean species: an experimental approach at a low radiant heat flux

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    One of the major factors influencing forest fuel combustion are terpenoids, a fraction of flammable Biogenic Volatile Organic Compounds (BVOCs) produced and stored by most Mediterranean species. The qualitative and quantitative effect of terpenoids on flammability has been only partially explained. In this study several major terpenoid-storing Mediterranean species (common cypress and three pines) were considered and compared to Holm oak as a reference non-storing species. The terpenoids were quantified via gas chromatography (GC-MS) analysis from both live fine fuel (LFF) and litter samples, and the relations between flammability and the terpenoids content were investigated by categories (Monoterpenoids, oxygenated Monoterpenoids, Sesquiterpenoids). The effect of fuel moisture content and species on ignition probability of LFF was also explored. A very different ignition probability was observed at the same fuel moisture content for the different species (Pinus spp. > C. sempervirens > Q. ilex). The stored terpenoids explained 19% to 50% of the whole flammability of both LFF and litter. Fuel moisture content (FMC) did not substantially change the relative effect of terpenoids on flammability, except in C. sempervirens. Monoterpenoids do not seem to significantly affect flammability, while sesquiterpenoids greatly influenced most flammability components, though their relative effect varied among species. A relation between storing structure of terpenoids and flammability was suggested. The results of this study indicate that isoprenoids should be included in physical models of the prediction and propagation of wildfire in Mediterranean vegetation as significant factors in driving flammability. © SISEF

    Synthesis and characterisation of a new benzamide-containing nitrobenzoxadiazole as a GSTP1-1 inhibitor endowed with high stability to metabolic hydrolysis

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    The antitumor agent 6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexan-1-ol (1) is a potent inhibitor of GSTP1-1, a glutathione S-transferase capable of inhibiting apoptosis by binding to JNK1 and TRAF2. We recently demonstrated that, unlike its parent compound, the benzoyl ester of 1 (compound 3) exhibits negligible reactivity towards GSH, and has a different mode of interaction with GSTP1-1. Unfortunately, 3 is susceptible to rapid metabolic hydrolysis. In an effort to improve the metabolic stability of 3, its ester group has been replaced by an amide, leading to N-(6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexyl)benzamide (4). Unlike 3, compound 4 was stable to human liver microsomal carboxylesterases, but retained the ability to disrupt the interaction between GSTP1-1 and TRAF2 regardless of GSH levels. Moreover, 4 exhibited both a higher stability in the presence of GSH and a greater cytotoxicity towards cultured A375 melanoma cells, in comparison with 1 and its analog 2. These findings suggest that 4 deserves further preclinical testing

    Dimethylmyricacene: An In Vitro and In Silico Study of a Semisynthetic Non-Camptothecin Derivative Compound, Targeting Human DNA Topoisomerase 1B

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    Human topoisomerase 1B regulates the topological state of supercoiled DNA enabling all fundamental cell processes. This enzyme, which is the unique molecular target of the natural anticancer compound camptothecin, acts by nicking one DNA strand and forming a transient protein–DNA covalent complex. The interaction of human topoisomerase 1B and dimethylmyricacene, a compound prepared semisynthetically from myricanol extracted from Myrica cerifera root bark, was investigated using enzymatic activity assays and molecular docking procedures. Dimethylmyricacene was shown to inhibit both the cleavage and the religation steps of the enzymatic reaction, and cell viability of A-253, FaDu, MCF-7, HeLa and HCT-116 tumor cell lines

    Lower lid entropion secondary to treatment with alpha-1a receptor antagonist: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The use of alpha-1a receptor antagonists (tamsulosin) is widely accepted in the treatment of benign prostatic hypertrophy (BPH). It has previously been implicated as a causative agent in intra-operative floppy iris syndrome due to its effects on the smooth muscle. We report a case of lower lid entropion that may be related to a patient commencing treatment of tamsulosin.</p> <p>Case presentation</p> <p>A 74-year-old Caucasian man was started on alpha 1-a receptor antagonist (Tamsulosin) treatment for benign prostatic hypertrophy. Eight days later, he presented to the ophthalmology unit with a right lower lid entropion which was successfully treated surgically with a Weiss procedure.</p> <p>Conclusion</p> <p>We report a case of lower lid entropion that may be secondary to the recent use of an alpha-1a blocker (tamsulosin). This can be explained by considering the effect of autonomic blockade on alpha-1 receptors in the Muller's muscle on a patient that may already have an anatomical predisposition to entropion formation due to a further reduction in muscle tone.</p

    Electrocardiographic features, mapping and ablation of idiopathic outflow tract ventricular arrhythmias

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    Idiopathic outflow tract ventricular arrhythmias are ventricular tachycardias or premature ventricular contractions presumably not related to myocardial scar or disorders of ion channels. These arrhythmias have focal origin and display characteristic electrocardiographic features. The purpose of this article is to review the state of the art of diagnosis and treatment of idiopathic outflow tract ventricular arrhythmias

    Primary squamous cell carcinoma of major salivary gland: “Sapienza Head and Neck Unit” clinical recommendations

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    Primary squamous cell carcinoma of salivary gland (SCG) is an extremely rare type of malignant salivary gland tumor, which in turn results in scarcity of data available regarding both its treatment and associated genetic alterations. A retrospective analysis of 12 patients with primary SCG was conducted, along with analysis of the association between treatment, clinical/pathological characteristics, and outcomes. Most patients (8) were staged IVa, with the majority of them (10) having G3 fast growing cancer. Local and systemic recurrence were reported in only three out of nine parotid cases (0 out of 2 submandibular SCGs). In two out of eight patients local relapse occurred after integrated treatment, while recurrence occurred in two out of three patients undergoing exclusive surgery. Five patients eventually died. Treatment of resectable disease must be aggressive and multimodal, with achievement of loco-regional control in order to reduce rate of recurrence and improve outcomes. Metastatic disease would require a therapeutic strategy tailored to the molecular profile in order to improve the currently disappointing results

    Ethnic fragmentation and degree of urbanization strongly affect the discrimination power of Y-STR haplotypes in central Sahel

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    Y chromosome short tandem repeats (Y-STRs) are commonly used to identify male lineages for investigative and judicial purposes and could represent the only source of male-specific genetic information from unbalanced female-male mixtures. The Yfiler Plus multiplex, which includes twenty conventional and seven rapidly-mutating Y-STRs, represents the most discriminating patrilineal system commercially available to date. Over the past five years, this multiplex has been used to analyze several Eurasian populations, with a reported discrimination capacity (DC) approaching or corresponding to the highest possible value. However, despite the inclusion of rapidly mutating Y-STRs, extensive haplotype sharing was still reported for some African populations due to a number of different factors affecting the effective population size. In the present study, we analyzed 27 Y-STRs included in the Yfiler Plus multiplex and 82 Y-SNPs in central Sahel (northern Cameroon and western Chad), an African region characterized by a strong ethnic fragmentation and linguistic diversity. We evaluated the effects of population sub-structuring on genetic diversity by stratifying a sample composed of 431 males according to their ethnicity (44 different ethnic groups) and urbanization degree (four villages and four towns). Overall, we observed a low discrimination capacity (DC = 0.90), with 71 subjects (16.5 %) sharing 27 Y-STR haplotypes. Haplotype sharing was essentially limited to subjects with the same binary haplogroup, coming from the same location and belonging to the same ethnic group. Haplotype sharing was much higher in rural areas (average DC = 0.83) than urban settlements (average DC = 0.96) with a significant correlation between DC and census size (r = 0.89; p = 0.003). Notably, we found that genetic differentiation between villages from the same country (ΦST = 0.14) largely exceeded that found among countries (ΦST = 0.02). These findings have important implications for the choice of the appropriate reference population database to evaluate the statistical relevance of forensic Y-haplotype matches

    The effect of social media and infodemic on mental health during the COVID-19 pandemic: results from the COMET multicentric trial

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    On January 30, 2020, the World Health Organization (WHO) declared the status of pandemic due to the COVID-19 infection. The initial phases of the pandemic were characterized by uncertainty and public fears. In order to cope with such unexpected conditions, people adopted different coping strategies, including search for information, accessing Internet, and using social media. The present study based on the COMET collaborative research network aims to: (1) assess use of Internet and of social media among the Italian general population; (2) explore differences in web usage between people with pre-existing mental disorders and the general population; (3) identify changes over time in social media usage along the phase 1 of the pandemic; (4) identify the clinical, socio-demographic and contextual predictors of excessive use of social media. A significant increase in time spent on Internet, with an average time of 4.8 &amp; PLUSMN; 0.02 h per day, was found in the global sample of 20,720 participants. Compared with the general population, Internet use was significantly higher in people with pre-existing mental disorders (5.2 &amp; PLUSMN; 0.1 h vs. 4.9 &amp; PLUSMN; 0.02; p &lt; 0.005). According to the multivariate logistic regression model, the risk of excessive use of social media and Internet was significantly higher in people with moderate levels of depressive symptoms (OR: 1.26, CI 95%: 0.99 to 1.59, p &lt; 0.0.005); while protective factors were being students (OR: 0.72, CI 95%: 0.53 to 0.96, p &lt; 0.0029) and living in central Italy (OR: 0.46, CI 95%: 0.23 to 0.90, p &lt; 0.002). The evaluation of social media and Internet use by the general population represents a first step for developing specific protective and supportive interventions for the general population, including practical suggestions on how to safely use Internet and social media
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