N,N-dialchilcarbammati di cerio(III) e lantanio (III) quali precursori di ossidi

In questo lavoro di tesi è stato esteso al cerio(III) e al lantanio(III) il metodo di estrazione da fase acquosa in solvente idrocaburico (eptano), utilizzando dibutilammina/CO2 come agenti estraenti, già applicato a un'ampia serie di centri labili, tra cui alcuni lantanidi (Nd, Eu, Tb, Sm). L'estrazione che avviene riproducibilmente in alte rese permette di preparare specie di composizione Ce(O2CNBu2)3 e La4(CO3)(O2CNBu2)10, che sono state caratterizzate analiticamente. Sono stati condotti studi preliminari di idrolisi totale dei complessi preparati utilizzando una soluzione di H2O/THF. Il processo di idrolisi è stato studiato al variare della temperatura e fornisce in ogni caso carbonati o idrossocarbonati di cerio. Le fasi ottenute sono state riconosciute per confronto dello spettro di polveri con fasi presenti nella banca dati ed associati a vari minerali. A temperatura ambiente è stata preparata una specie di composizione La2(CO3)3·7H2O (una fase presente nel minerale lantanite), a 70 °C è stata preparata una specie Ce(OH)(CO3) (fase presente nel minerale ancylite) e a 40 °C è stata preparata una specie di composizione La2(CO3)3·4H2O, una fase presente nel minerale calchinsite, la cui preparazione non era mai stata riportata in letteratura. Per trattamento termico all'aria a 200°C dei carbonati così ottenuti è stato possibile preparare campioni di ceria caratterizzati da cristalliti nanometrici (4 – 8 nm) ed area superficiale di 79,6 m2/g. Prodotti con area superficiale doppia (147 m2/g) sono stati successivamente preparati conducendo l'idrolisi in presenza di dibutilammina quale surfattante. Concordemente studi di microscopia elettronica hanno rilevato particelle separate di CeO2 di dimensione intorno a 3 – 4 nm. Seguendo lo stesso protocollo sono stati preparati una ceria drogata con lantanio al 10 % per idrolisi di una miscela di carbammati metallici seguita da trattamento termico a bassa temperatura, ed un ossido misto La2CuO4 per idrolisi di una miscela di dibutilcarbammati di rame e lantanio nel rapporto stechiometrico corretto

Therapeutic Activity of Lenalidomide in Mantle Cell Lymphoma and Indolent Non-Hodgkin's Lymphomas

Mantle cell lymphoma (MCL) comprises 3–10% of NHL, with survival times ranging from 3 and 5 years. Indolent lymphomas represent approximately 30% of all NHLs with patient survival largely dependent on validated prognostic scores. High response rates are typically achieved in these patients with current first-line chemoimmunotherapy. However, most patients will eventually relapse and become chemorefractory with poor outcome. Alternative chemoimmunotherapy regimens are often used as salvage strategy and stem cell transplant remains an option for selected patients. However, novel approaches are urgently needed for patients no longer responding to conventional chemotherapy. Lenalidomide is an immunomodulatory drug with activity in multiple myeloma, myelodisplastic syndrome and chronic lymphoproliferative disorders. In phase II studies of indolent NHL and MCL lenalidomide has shown activity with encouraging response rates, both as a single agent and in combination with other drugs. Some of these responses may be durable. Optimal dose of lenalidomide has not been defined yet. The role of lenalidomide in the therapeutic armamentarium of patients with indolent NHL or MCL will be discussed in the present paper

Launcher vehicle aerothermodynamics and fairing separation altitude effects on payload temperature

The first part of this research investigates and compares VEGA launcher vehicle aerothermodynamics during a nominal ascent trajectory simulated by means of Direct Simulation Monte Carlo and hypersonic local panel methods. In the second part of the work, the coupled aerothermal-structural simulation of the ascent phase up to 250s was performed, studying the heat transfer between the payload fairing and a dummy payload. The results have shown a good match among the aerothermal fluxes estimated by the different methodologies, and that an optimal theoretical fairing separation time can be found by minimizing the aerothermal fluxes incident on the payload

The devil is in the fine-grained details: Evaluating open-vocabulary object detectors for fine-grained understanding

Recent advancements in large vision-language models enabled visual object detection in open-vocabulary scenarios, where object classes are defined in free-text formats during inference. In this paper, we aim to probe the state-of-the-art methods for open-vocabulary object detection to determine to what extent they understand fine-grained properties of objects and their parts. To this end, we introduce an evaluation protocol based on dynamic vocabulary generation to test whether models detect, discern, and assign the correct fine-grained description to objects in the presence of hard-negative classes. We contribute with a benchmark suite of increasing difficulty and probing different properties like color, pattern, and material. We further enhance our investigation by evaluating several state-of-the-art open-vocabulary object detectors using the proposed protocol and find that most existing solutions, which shine in standard open-vocabulary benchmarks, struggle to accurately capture and distinguish finer object details. We conclude the paper by highlighting the limitations of current methodologies and exploring promising research directions to overcome the discovered drawbacks. Data and code are available at https://lorebianchi98.github.io/FG-OVD/.Comment: Accepted as Highlight at CVPR202

Partial and exhaustive hydrolysis of lanthanide N,N-dialkylcarbamato complexes. A viable access to lanthanide mixed oxides

Partial hydrolysis (H2O/Ln molar ratio = ¼) of lanthanum di-iso-propylcarbamato complex, [La(O2CNiPr2)3], 1, afforded the tetranuclear μ-oxo derivative [La4O(O2CNiPr2)10], 2, which was structurally characterized by single crystal X-Ray diffraction studies. The carbonatocarbamato derivative of lanthanum, [La4(CO3)(O2CNBu2)10], 3, was prepared by extraction of lanthanum ions from aqueous solution into heptane by the NHBu2/CO2 system. Partial hydrolysis (H2O/Ln molar ratio = ½ ) of N,N-di-iso-propylcarbamato complexes of neodymium, europium, gadolinium and terbium, [Ln(O2CNiPr2)3], yielded the derivatives [Ln2(CO3)(O2CNiPr2)4] (Ln = Nd, 4, Eu, 5, Gd, 6). Exhaustive hydrolysis of [Ln(O2CNR2)3] (Ln = Nd, Tb, R = Bu; Ln = Eu, Gd, R = iPr, Bu) produced hydrated lanthanide carbonates, Ln2(CO3)3 n H2O. For sake of comparison with a block d metal, the exhaustive hydrolysis of two copper(II) carbamato complexes, [Cu(O2CNEt2)2(NHEt2)]2 and [Cu(O2CNiPr2)2], was carried out with formation in both cases of the hydrated basic carbonate Cu2(OH)2(CO3)nH2O. The exhaustive hydrolysis of mixtures of cerium and lanthanum or cerium and terbium N,N-dibutylcarbamato complexes allowed the preparation of mixed oxides containing the two metals in the desired molar ratio, via the intermediate formation of the corresponding mixed carbonates

Overexpression of lpxT Gene in Escherichia coli Inhibits Cell Division and Causes Envelope Defects without Changing the Overall Phosphorylation Level of Lipid A

LpxT is an inner membrane protein that transfers a phosphate group from the essential lipid undecaprenyl pyrophosphate (C-55PP) to the lipid A moiety of lipopolysaccharide, generating a lipid A tris-phosphorylated species. The protein is encoded by the non-essential lpxT gene, which is conserved in distantly related Gram-negative bacteria. In this work, we investigated the phenotypic effect of lpxT ectopic expression from a plasmid in Escherichia coli. We found that lpxT induction inhibited cell division and led to the formation of elongated cells, mostly with absent or altered septa. Moreover, the cells became sensitive to detergents and to hypo-osmotic shock, indicating that they had cell envelope defects. These effects were not due to lipid A hyperphosphorylation or C-55PP sequestering, but most likely to defective lipopolysaccharide transport. Indeed, lpxT overexpression in mutants lacking the L,D-transpeptidase LdtD and LdtE, which protect cells with outer membrane defects from osmotic lysis, caused cell envelope defects. Moreover, we found that pyrophosphorylated lipid A was also produced in a lpxT deletion mutant, indicating that LpxT is not the only protein able to perform such lipid A modification in E. coli

A convenient preparation of La2CuO4 from molecular precursors

Exhaustive hydrolysis of a mixture of [La4(CO3)(O2CNBu2)10] and [Cu(O2CNBu2)(py∗)2] (py∗ = 4-dimethylamino pyridine) in molar ratio 1/2 corresponding to a La/Cu molar ratio 2/1 was carried out in toluene at room temperature. The carbamato derivatives of lanthanum and copper can be easily prepared by extraction of the metal ions from aqueous solution into heptane by the NHBu2/CO2 system, according to a method previously reported. The copper precursor was selected among a number of derivatives in respect of its easy tractability. The tetragonal modification T’ of La2CuO4 was obtained by treatment at 600 °C of the intermediate mixed carbonate. The thermal treatment of T’-La2CuO4 at 850 °C, followed by cooling down to room temperature, afforded the orthorhombic modification of the mixed oxide

A case of nodular sclerosis Hodgkin’s lymphoma repeatedly relapsing in the context of composite plasma cell-hyaline vascular Castleman’s disease: successful response to rituximab and radiotherapy

We report the case of an Epstein-Barr virus (EBV)- and human immunodeficiency virus-serum negative patient suffering from repeatedly relapsing classical Hodgkin’s Lymphoma (cHL) associated with a histological picture of plasma cell-hyaline vascular (PC-HV) form of Castleman’s disease (CD). The CD30- and CD15- positive, Reed-Sternberg/Hodgkin cells, only occasionally expressed the CD20 molecule, but not leukocyte common antigen and latent membrane protein-1. Single-strand polymerase chain reaction failed to detect human herpesvirus 8 or EBV in the involved tissues. At the time of second relapse in July 2005, the clinical picture was characterized by a palpable right hypogastric mass, disclosed at physical exam, in the absence of other enlarged peripheral lymph nodes, subjective symptoms or laboratory profile alterations. Combined hybrid-(18)F-fluorodeoxyglucose positron emission-computerized tomography (18F-FDG PET/CT) showed increased radionuclide uptake in multiple external iliac lymph nodes [standardized uptake value (SUV) of 7.4] and non-palpable left supraclavicular lymph nodes (SUV of 5.8). Relapsing cHL in the context of mixed PC-HV CD was documented in two of three surgically excised abdominal lymph nodes never previously enlarged or involved by any lymphoproliferative disease. Because of the limited disease extension and failure to induce continuous remission with previous conventional chemoradiotherapy, the patient was treated with six rituximab injections. This immunotherapy induced significant reduction in size of supraclavicular lymph nodes as evident at ultrasound (US) scan (<1 vs. 2.5 cm, post- vs. pretherapy), which was confirmed by the 18F-FDG PET/CT in October 2005, despite no modification in SUV of 4.2. 18F-FDG PET/CT also disclosed no radionuclide uptake by abdominal lymph nodes. Thus, a second course of four additional rituximab injections was given and subsequent 18F-FDG PET/CT indicated persistent, but reduced incorporation of radionuclide compared to the pretherapy value (SUV of 2.7) in the supraclavicular area and confirmed a normal metabolic activity in the iliac external lymph nodes. Because of uncertain persistent disease in the supraclavicular nodal site, involved-field radiotherapy (RT) was delivered in that area as consolidation treatment. After completion of rituximab and RT for 16 and 14 months respectively, US and 18F-FDG PET/CT exams were indicative of complete remission. This case is in concordance with previously published data suggesting that rituximab immunotherapy might be a valid option in the treatment of CD and also have a role in the management of relapsing cHL