Understanding the dynamics of social media influence : empirical analysis of the determinants of retweeting

LAUREA MAGISTRALEThis graduate thesis is part of a wider research project whose aim is to analyze influence dynamics on social media. Literature focused its efforts into studying the role of influencers, i.e. users who have a broad audience (e.g. they possess many followers on Twitter). The term influence, instead, refers to the social impact of the content shared, regardless of who published it: the key point is the ability of the message subject to raise audience attention on its own. Though we are aware of the importance of being an influencer, our assertion is that message content possesses a decisive role in generating influence, irrespective of its author. Hypotheses testing is here performed with the aim of evaluating content significance in influence generation. An in-house software was built in order to support all the stages this thesis work consists of. The first step assesses the weight of content specificity (i.e. level of detail) at user level, considering also tweeting volumes. Empirical results highlight a positive correlation between specificity and influence, while high volumes show a strongly negative connection with the possibility of being retweeted. Even when the popularity of the user is taken into account, specificity is shown to keep holding a positive effect over messages distribution. The following section analyzes influence dynamics at single post level, without the bias of author variables: this is a crucial stage, where a clear distinction between influence and influencers is performed. Sentiment (i.e. feelings being conveyed) and specificity are the employed variables. Data show a perfect fit to the model, validating the positive relationship between specificity and influence. As regards sentiment, the need of a few negative messages is displayed while seeking for a larger amount of retweets. The final step of the work exploits data clustering, with the intention of verifying at which level specificity stops playing a significant role in influence generation. Empirical findings are converted into guidelines, useful for both private users and corporations as a starting point for building a self-promoting strategy

ROBOT MINDSTROM EV3 UNTUK MELETAKKAN BARANG DI STORAGE PLACE BERDASARKAN WARNA DAN LINE FOLLOWERS

PembuatanLaporanAkhirinibertujuanuntukmembuatdanmengembangkancarakerja robot Lego Mindstorms EV3. Lego Mindstorms EV3inidapatdibuatsesuaikeinginanuserdandapatdirakitdenganberbagaibentuksesuaikebutuhan. Robot inidapatdigunakanuntukmemindahkanbendaberwarnakestorage placebertingkatdanmeletakkannyaberdasarkanwarnapadabendatersebut. Penulismenyarankan agar dalampembuatanalatiniadanyapengembanganlebihlanjutdalammekanikmaupun program dari robot yang dibuatdenganmenambahkan sensor lainnyaseperti sensor touch, sensor gyro, sensor ultrasonic agar pembacaanjaraklebihakurandankerja robot lebihsempurna

Synthesis of novel 3,4-dihydroquinoxalin-2(1H)-one derivatives

New derivatives of 3,4-dihydroquinoxaline-2(1H)-one were synthesized and characterized. Representative examples were evaluated for their antimicrobial and antifungal activities using Tetracycline and Nystatin as reference compound. One of the tested compounds 10a was found to exhibit slight activity against Staphylococcus aureus. Compounds 10b, 11b and 14b showed slight activity against Escherichia coli. Moreover, nineteen compounds were screened for their inhibition effect on CDK5, CK1, and GSK-3β. None of the tested compounds showed an inhibition activity below 10 µM concentration

Treatment with metformin in twelve patients with Lafora disease

Background: Lafora disease (LD) is a rare, lethal, progressive myoclonus epilepsy for which no targeted therapy is currently available. Studies on a mouse model of LD showed a good response to metformin, a drug with a well known neuroprotective effect. For this reason, in 2016, the European Medicines Agency granted orphan designation to metformin for the treatment of LD. However, no clinical data is available thus far. Methods: We retrospectively collected data on LD patients treated with metformin referred to three Italian epilepsy centres. Results: Twelve patients with genetically confirmed LD (6 EPM2A, 6 NHLRC1) at middle/late stages of disease were treated with add-on metformin for a mean period of 18 months (range: 6-36). Metformin was titrated to a mean maintenance dose of 1167 mg/day (range: 500-2000 mg). In four patients dosing was limited by gastrointestinal side-effects. No serious adverse events occurred. Three patients had a clinical response, which was temporary in two, characterized by a reduction of seizure frequency and global clinical improvement. Conclusions: Metformin was overall safe in our small cohort of LD patients. Even though the clinical outcome was poor, this may be related to the advanced stage of disease in our cases and we cannot exclude a role of metformin in slowing down LD progression. Therefore, on the grounds of the preclinical data, we believe that treatment with metformin may be attempted as early as possible in the course of LD

Next-generation sequencing in pediatric-onset epilepsies: Analysis with target panels and personalized therapeutic approach

Objective: The objective of this study is to report the results of the genetic analysis in a large and well-characterized population with pediatric-onset epilepsies and to identify those who could benefit from precision medicine treatments. Methods: In this retrospective observational study, we consecutively recruited patients with pediatric-onset epilepsy observed at a tertiary neurological center over a time span of 7 years, collecting clinical and laboratory findings. Following in-depth diagnostic process to exclude possible structural and metabolic causes of the disease, patients with a suspected genetically determined etiology underwent next-generation sequencing (NGS) screening with panels for the analysis of target genes causative of epilepsy. Results: We detected likely pathogenic or pathogenic variants (classes IV and V) in 24% of the 562 patients who underwent genetic investigations. By the evaluation of patients' data, we observed that some features (onset of epilepsy before one year old, presence of neurological deficits, psychomotor delay/cognitive disability, and malformative aspects at brain MRI) were significantly associated with class IV or V variants. Moreover, statistical analysis showed that the diagnostic yield resulted higher for patients affected by Progressive Myoclonic Epilepsy (PME) and with early onset developmental and epileptic encephalopathies (DEE), compared with focal epilepsies, genetic generalized epilepsies, DEE with onset at/after 1 y.o., and unclassified epileptic syndromes. According to the results of the genetic screening, up to 33% of patients carrying class IV or V variants resulted potentially eligible for precision medicine treatments. Significance: The large-scale application of NGS multigene panels of analysis is a useful tool for the molecular diagnosis of patients with pediatric-onset epilepsies, allowing the identification of those who could benefit from a personalized therapeutic approach. Plain Language Summary: The analysis of patients with pediatric-onset epilepsy using advanced technologies for the screening of all the implicated genes allows the identification of the cause of diseases in an ever-increasing number of cases. Understanding the pathogenic mechanisms could, in some cases, guide the selection and optimization of appropriate treatment approaches for patients

Functional Characterization of Two Variants at the Intron 6-Exon 7 Boundary of the KCNQ2 Potassium Channel Gene Causing Distinct Epileptic Phenotypes

Pathogenic variants in KCNQ2 encoding for Kv7.2 potassium channel subunits have been found in patients affected by widely diverging epileptic phenotypes, ranging from Self-Limiting Familial Neonatal Epilepsy (SLFNE) to severe Developmental and Epileptic Encephalopathy (DEE). Thus, understanding the pathogenic molecular mechanisms of KCNQ2 variants and their correlation with clinical phenotypes has a relevant impact on the clinical management of these patients. In the present study, the genetic, biochemical, and functional effects prompted by two variants, each found in a non-familial SLNE or a DEE patient but both affecting nucleotides at the KCNQ2 intron 6-exon 7 boundary, have been investigated to test whether and how they affected the splicing process and to clarify whether such mechanism might play a pathogenetic role in these patients. Analysis of KCNQ2 mRNA splicing in patient-derived lymphoblasts revealed that the SLNE-causing intronic variant (c.928-1G > C) impeded the use of the natural splice site, but lead to a 10-aa Kv7.2 in frame deletion (Kv7.2 p.G310Δ10); by contrast, the DEE-causing exonic variant (c.928G > A) only had subtle effects on the splicing process at this site, thus leading to the synthesis of a full-length subunit carrying the G310S missense variant (Kv7.2 p.G310S). Patch-clamp recordings in transiently-transfected CHO cells and primary neurons revealed that both variants fully impeded Kv7.2 channel function, and exerted strong dominant-negative effects when co-expressed with Kv7.2 and/or Kv7.3 subunits. Notably, Kv7.2 p.G310S, but not Kv7.2 p.G310Δ10, currents were recovered upon overexpression of the PIP2-synthesizing enzyme PIP5K, and/or CaM; moreover, currents from heteromeric Kv7.2/Kv7.3 channels incorporating either Kv7.2 mutant subunits were differentially regulated by changes in PIP2 availability, with Kv7.2/Kv7.2 G310S/Kv7.3 currents showing a greater sensitivity to PIP2 depletion when compared to those from Kv7.2/Kv7.2 G310Δ10/Kv7.3 channels. Altogether, these results suggest that the two variants investigated differentially affected the splicing process at the intron 6-exon 7 boundary, and led to the synthesis of Kv7.2 subunits showing a differential sensitivity to PIP2 and CaM regulation; more studies are needed to clarify how such different functional properties contribute to the widely-divergent clinical phenotypes

Progressive myoclonus epilepsies due to SEMA6B mutations. New variants and appraisal of published phenotypes

Variants of SEMA6B have been identified in an increasing number of patients, often presenting with progressive myoclonus epilepsy (PME), and to lesser extent developmental encephalopathy, with or without epilepsy. The exon 17 is mainly involved, with truncating mutations causing the production of aberrant proteins with toxic gain of function. Herein, we describe three adjunctive patients carrying de novo truncating SEMA6B variants in this exon (c.1976delC and c.2086C > T novel; c.1978delC previously reported). These subjects presented with PME preceded by developmental delay, motor and cognitive impairment, worsening myoclonus, and epilepsy with polymorphic features, including focal to bilateral seizures in two, and non-convulsive status epilepticus in one. The evidence of developmental delay in these cases suggests their inclusion in the “PME plus developmental delay” nosological group. This work further expands our knowledge of SEMA6B variants causing PMEs. However, the data to date available confirms that phenotypic features do not correlate with the type or location of variants, aspects that need to be further clarified by future studie

Relapse risk factors in anti-N-methyl-D-aspartate receptor encephalitis

Aim: To identify factors that may predict and affect the risk of relapse in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Method: This was a retrospective study of an Italian cohort of patients with paediatric (≤18y) onset anti-NMDAR encephalitis. Results: Of the 62 children included (39 females; median age at onset 9y 10mo, range 1y 2mo–18y; onset between 2005 and 2018), 21 per cent relapsed (median two total events per relapsing patient, range 2–4). Time to first relapse was median 31.5 months (range 7–89mo). Severity at first relapse was lower than onset (median modified Rankin Scale [mRS] 3, range 2–4, vs median mRS 5, range 3–5; admission to intensive care unit: 0/10 vs 3/10). At the survival analysis, the risk of relapsing was significantly lower in patients who received three or more different immune therapies at first disease event (hazard ratio 0.208, 95% confidence interval 0.046–0.941; p=0.042). Neurological outcome at follow-up did not differ significantly between patients with relapsing and monophasic disease (mRS 0–1 in 39/49 vs 12/13; p=0.431), although follow-up duration was significantly longer in relapsing (median 84mo, range 14–137mo) than in monophasic patients (median 32mo, range 4–108mo; p=0.002). Interpretation: Relapses may occur in about one-fifth of children with anti-NMDAR encephalitis, are generally milder than at onset, and may span over a long period, although they do not seem to be associated with severity in the acute phase or with outcome at follow-up. Aggressive immune therapy at onset may reduce risk of relapse. What this paper adds: Relapses of anti-N-methyl-D-aspartate receptor encephalitis may span over a long period. Relapses were not associated with severity in the acute phase or outcome at follow-up. Aggressive immune therapy at onset appears to decrease risk of relapse

neuroimaging changes in menkes disease part 2

SUMMARY: This is the second part of a retrospective and review MR imaging study aiming to define the frequency rate, timing, imaging features, and evolution of gray matter changes in Menkes disease, a rare multisystem X-linked disorder of copper metabolism characterized by early, severe, and progressive neurologic involvement. According to our analysis, neurodegenerative changes and focal basal ganglia lesions already appear in the early phases of the disease. Subdural collections are less common than generally thought; however, their presence remains important because they might challenge the differential diagnosis with child abuse and might precipitate the clinical deterioration. Anecdotal findings in our large sample seem to provide interesting clues about the protean mechanisms of brain injury in this rare disease and further highlight the broad spectrum of MR imaging findings that might be expected while imaging a child with the suspicion of or a known diagnosis of Menkes disease