642 research outputs found

    Investigations Into The Chemoselective Modification Of THAM Directed Towards Biological Applications

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    Tris(hydroxymethyl)aminomethane (THAM) was a readily-available and economical amino-triol that was viewed as having a large untapped potential as a starting material. The full chemoselective functionalization and differentiation of the amino group and the three primary alcohol residues present in THAM was extensively investigated. The development of this methodology allowed for the rapid assembly of a differentiated core that lead to existing and new potential drug scaffolds. The discovery of a novel oxidative fragmentation and rearrangement process was made leading to the synthesis of differentiated oxazolidinone rings. This process allowed for the creation of novel chemical library situated around THAM-based oxazolidinones, as well as THAM-based 1,3-dioxanes. THAM was also used as a starting material for sphingosine analogs, including sphingosine 1-phosphate (S1P) and anticancer S1K inhibitors. Selective functionalization of the amine and one alcohol within an oxazolidinone ring allowed access to a new family of Linezolid-type oxazolidinones as well. Additionally, various triazole-based compounds were prepared, which allowed access to a new family of potential antifungal agents based on the lead compound Fluconazole. A total synthesis of the immunosuppressant molecule FTY720 was also reported, employing double Wittig-olefination protocol, from THAM. This synthesis avoided certain pitfalls that were present in previously documented literature methods. Along the pathway to FTY720, many intermediates and analogs were synthesized and tested for biological activity alongside the novel oxazolidinone compounds, resulting in interesting lead compounds for various biological applications. A UV-active FTY720 scaffold was also synthesized for potential future in vivo tracking of the immunosuppressant and its metabolites.Doctor of Philosophy (PhD

    Dark solitons in the unitary Bose gas

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    We study the dilute and ultracold unitary Bose gas, which is characterized by a universal equation of state due to the diverging s-wave scattering length, under a transverse harmonic confinement. From the hydrodynamic equations of superfluids we derive an effective one-dimensional nonpolynomial Schr\"odinger equation (1D NPSE) for the axial dynamics which, however, takes also into account the transverse dynamics. Finally, by solving the 1D NPSE we obtain meaningful analytical formulas for the dark (gray and black) solitons of the bosonic system.Comment: 13 pages, 4 figures, improved versio

    Clinical and molecular characterization of 40 patients with classic Ehlers--Danlos syndrome: identification of 18 COL5A1 and 2 COL5A2 novel mutations.

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    Classic Ehlers-Danlos syndrome (cEDS) is a rare autosomal dominant connective tissue disorder that is primarily characterized by skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. A recent study demonstrated that more than 90% of patients who satisfy all of these major criteria harbor a type V collagen (COLLV) defect. This cohort included 40 patients with cEDS who were clinically diagnosed according to the Villefranche nosology. The flowchart that was adopted for mutation detection consisted of sequencing the COL5A1 gene and, if no mutation was detected, COL5A2 analysis. In the negative patients the presence of large genomic rearrangements in COL5A1 was investigated using MLPA, and positive results were confirmed via SNP-array analysis. We report the clinical and molecular characterization of 40 patients from 28 families, consisting of 14 pediatric patients and 26 adults. A family history of cEDS was present in 9 patients. The majority of the patients fulfilled all the major diagnostic criteria for cEDS; atrophic scars were absent in 2 females, skin hyperextensibility was not detected in a male and joint hypermobility was negative in 8 patients (20% of the entire cohort). Wide inter- and intra-familial phenotypic heterogeneity was observed. We identified causal mutations with a detection rate of approximately 93%. In 25/28 probands, COL5A1 or COL5A2 mutations were detected. Twenty-one mutations were in the COL5A1 gene, 18 of which were novel (2 recurrent). Of these, 16 mutations led to nonsense-mediated mRNA decay (NMD) and to COLLV haploinsufficiency and 5 mutations were structural. Two novel COL5A2 splice mutations were detected in patients with the most severe phenotypes. The known p. (Arg312Cys) mutation in the COL1A1 gene was identified in one patient with vascular-like cEDS. Our findings highlight that the three major criteria for cEDS are useful and sufficient for cEDS clinical diagnosis in the large majority of the patients. The borderline patients for whom these criteria fail can be diagnosed when minor signs of connective tissue diseases and family history are present and when genetic testing reveals a defect in COLLV. Our data also confirm that COL5A1 and COL5A2 are the major, if not the only, genes involved in cEDS

    A hard lesson: Assessing the HTTPS deployment of Italian university websites

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    In this paper we carry out a systematic analysis of the state of the HTTPS deployment of the most popular Italian university websites. Our analysis focuses on three different key aspects: HTTPS adoption and activation, HTTPS certificates, and cryptographic TLS implementations. Our investigation shows that the current state of the HTTPS deployment is unsatisfactory, yet it is possible to significantly improve the level of security by working exclusively at the web application layer. We hope this observation will encourage site operators to take actions to improve the current state of protection

    Verifiable Learning for Robust Tree Ensembles

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    Verifying the robustness of machine learning models against evasion attacks at test time is an important research problem. Unfortunately, prior work established that this problem is NP-hard for decision tree ensembles, hence bound to be intractable for specific inputs. In this paper, we identify a restricted class of decision tree ensembles, called large-spread ensembles, which admit a security verification algorithm running in polynomial time. We then propose a new approach called verifiable learning, which advocates the training of such restricted model classes which are amenable for efficient verification. We show the benefits of this idea by designing a new training algorithm that automatically learns a large-spread decision tree ensemble from labelled data, thus enabling its security verification in polynomial time. Experimental results on public datasets confirm that large-spread ensembles trained using our algorithm can be verified in a matter of seconds, using standard commercial hardware. Moreover, large-spread ensembles are more robust than traditional ensembles against evasion attacks, at the cost of an acceptable loss of accuracy in the non-adversarial setting

    Can i take your subdomain? Exploring same-site attacks in the modern web

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    Related-domain attackers control a sibling domain of their target web application, e.g., as the result of a subdomain takeover. Despite their additional power over traditional web attackers, related-domain attackers received only limited attention from the research community. In this paper we define and quantify for the first time the threats that related-domain attackers pose to web application security. In particular, we first clarify the capabilities that related-domain attackers can acquire through different attack vectors, showing that different instances of the related-domain attacker concept are worth attention. We then study how these capabilities can be abused to compromise web application security by focusing on different angles, including cookies, CSP, CORS, postMessage, and domain relaxation. By building on this framework, we report on a large-scale security measurement on the top 50k domains from the Tranco list that led to the discovery of vulnerabilities in 887 sites, where we quantified the threats posed by related-domain attackers to popular web applications

    Structured Expert Consensus on Actinic Keratosis:Treatment Algorithm Focusing on Daylight PDT

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    BACKGROUND: A practical and up-to-date consensus among experts is paramount to further improve patient care in actinic keratosis (AK). OBJECTIVES: To develop a structured consensus statement on the diagnosis, classification, and practical management of AK based on up-to-date information. METHODS: A systematic review of AK clinical guidelines was conducted. This informed the preparation of a 3-round Delphi procedure followed by a consensus meeting, which combined the opinions of 16 clinical experts from 13 countries, to construct a structured consensus statement and a treatment algorithm positioning daylight photodynamic therapy (dl-PDT) among other AK treatment options. RESULTS: The systematic review found deficiencies in current guidelines with respect to new AK treatments such as ingenol mebutate and dl-PDT. The Delphi panel established consensus statements across definition, diagnosis, classification, and management of AK. While the diagnosis of AK essentially rests on the nature of lesions, treatment decisions are based on several clinical and nonclinical patient factors and diverse environmental attributes. Participants agreed on ranked treatment preferences for the management of AK and on classifying AK in 3 clinical situations: isolated AK lesions requiring lesion-directed treatment, multiple lesions within a small field, and multiple lesions within a large field, both requiring specific treatment approaches. Different AK treatment options were discussed for each clinical situation. CONCLUSIONS: The results provide practical recommendations for the treatment of AK, which are readily transferable to clinical practice, and incorporate the physician's clinical judgement. The structured consensus statement positioned dl-PDT as a valuable option for patients with multiple AKs in small or large fields
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