1,517 research outputs found
Development, characterization and applications of new sub-2micron totally porous WhelkO-1 brush-type and macrocyclic chiral stationary phases
No full textOver the last ten years, the technological progress has led to the development of stationary phases on ever smaller silica particles and instuments (UHPLC/UHPSFC) with a reduced extra-column volume able to reach very high pressure. These innovations allow to obtain higher efficiencies, resolutions and permit to reduce the analysis time and the eluent consumption. For these reasons also chiral stationary phases (CSPs) are moving to sub-2μm particles diameter. This talk concerns the development of two different sub-2μm CSPs based on the WhelkO-1 [1] and on the teicoplanin macrocyclic selectors[2]. The first selector has been covalently bonded on fully porous 1.8 μm Kromasil and the second one on totally porous and monodispersed 1.9 μm Titan silica particles (TEICO-Titan). Both CSPs were packed in columns with an internal diameter of 4.6 mm and different lengths, from 10 cm down to 1 cm, the latter geometry permitting very short analysis time. The different columns containing the two CSPs were analyzed under several elution conditions to obtain a complete thermodynamic and kinetic characterization. The UHPLC columns packed with the brush-type WhelkO-1-CSP were evaluated using normal phase and supercritical fluid eluents. Kinetic performances were estimated using trans-stilbene oxide as a probe, and resulted in efficiencies up to 250’000 plates/m at the optimal flow-rate of 2.0 mL/min under normal phase elution conditions. To evaluate the thermodynamic performances a large library screening[3] was performed using carbon dioxide based eluents under sub-critical fluid conditions: in one working day, 81 out of 129 randomly collected racemates were resolved under identical eluting conditions using a 9 min methanol in CO2 gradient with 0.1% TFA or 0.1% NH3 added for acidic and basic compounds, respectively.
The TEICO-Titan 1.9 μm CSP showed a broad field of application in different environments (reversed phase, polar organic mode, sub-critical fluid and normal phase). The thermodynamic performances of the new TEICO-Titan 1.9 μm have been evaluated with several N-protected amino acids, aryloxy acids, pharmaceutical compounds, sulfoxides and phosphine oxides. This CSP frequently showed high enantio-selectivity values: these resulted in large resolutions on the 10 cm long column (Rs up to 10.7 with Fmoc-D,L-Ala) and allowed the use of 2 cm and even 1 cm long columns in many cases, providing a considerable reduction of the analysis time maintaining a baseline enantiomeric separation.
References
[1] D. Kotoni, A. Ciogli, C. Molinaro, I. D’Acquarica, J. Kocergin, T. Szczerb, H. Ritchie, C. Villani, F. Gasparrini, Anal. Chem., 84 (2012), 6805
[2] Berthod A., Chen X., Kullman J.P., Armstrong D.W., Gasparrini F., D’Acquarica I., Villani C., Carotti A., Anal. Chem. 72 (2000) 1767-1780;
[3] L. Sciascera, O. Ismail, A. Ciogli, D. Kotoni, A. Cavazzini, L. Botta, T. Szczerba, J. Kocergin, C. Villani, F. Gasparrini, JCA, 1383 (2015) 160–16
From Albania to Brazil: Ismail Kadaré's Broken april and its filmic adaptation, Walter Salles' Abril despedaçado
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Letras/Inglês e Literatura Correspondente, Florianópolis, 2007The aim of the present study is to analyse how issues of Albanian national identity are portrayed in Ismail Kadaré's novel Broken April (Prilli i Thyer), and how such features have been appropriated and translated onto the screen into a Northeastern Brazilian context. I depart from the premise that, even though Brazilian elements are indeed shown in the film, the non existence of the Kanun in Brazil, and the use of narrative techniques different from the ones employed in the novel render the story of the blood feuds in the film more universal than the genuinely Albanian reality depicted in the novel. In sum, the appropriation transcends the Albanian reality into a universal context, showing, at the same time, elements which are typical of the Brazilian culture.O objetivo do presente estudo é analisar como questões sobre a identidade nacional Albanesa são retratadas no romance Abril Despedaçado (Prilli i Thyer), de Ismail Kadaré, e como tais questões foram apropriadas e traduzidas para a tela num contexto Nordestino-Brasileiro. O estudo parte do princípio que, embora elementos tipicamente Brasileiros sejam mostrados no filme, a não existência do Kanun no Brasil, e o uso de técnicas narrativas diferentes das empregadas no romance ajudam a deixar a história das brigas de família no filme com um aspecto mais universal do que a realidade genuinamente Albanesa representada na romance. Em suma, a apropriação transcende a realidade Albanesa para um contexto mais universal, sem deixar de mostrar também elementos típicos da cultura Brasileira
Exploring the potential of zwitterionic teicoplanin-based CSPs by using macroporous superficially porous silica particles 2.7 μm 160Å and 3.4 μm 400Å
No full textDuring the last years, the research in the enantioselective Ultra High Performance Chromatography (eUHPC) is going to push the limits of high efficient and ultrafast analyses. In this work, novel Chiral Stationary Phases (CSPs) were prepared by covalently bonding the teicoplanin selector (TE_A2-2) on Halo 2.7μm 160Å and 3.4μm 400Å Superficially Porous silica Particles (SPP). An innovative bonding protocol allowed to obtain a zwitterionic teicoplanin based CSP, which was used to produce the already known UHPC-FPP-Titan-Tzwitt CSP based on 1.9 μm 120Å Fully Porous monodispersed silica Particles (FPP) and UHPC-SPP-Halo90-Tzwitt CSP 2.0 μm [1-3]. Columns with an internal diameter of 4.6 mm and different lengths (50 and 100 mm) were packed with all CSPs and characterized in terms of permeability, efficiency and thermodynamic under HILIC conditions. The kinetic performance was evaluated through the use of van Deemter curves. The UHPC-SPP-Halo160-Tzwitt 2.7 μm column exhibited extremely high efficiencies on both achiral (>323,000 theoretical plates/meter, N/m; hr: 1.14) and chiral compounds (>240,000 N/m; hr: 1.53) under HILIC conditions, attesting the high potential of this CSP from the kinetic viewpoint. An extreme efficiency was recorded by using the HPC-SPP-Halo400-Tzwitt 3.4 μm column which allowed to achieve an efficiency of 280’000 N/m on naphthalene (hr: 1.05). Furthermore, taking into account the thermodynamic viewpoint, the UHPC-SPP-Halo160-Tzwitt 2.7 μm exhibited the highest resolution power (Rs/tr,2) thanks to its enantioselectivity values because of the higher selector density on the silica matrix. In conclusion, in this study we demonstrate the potential of the use of SPP macroporous silica particles in the UHPLC chiral field opening an interesting scenario in the chiral chromatography area.
[1] O.H. Ismail, A. Ciogli, C. Villani, M. De Martino, M. Pierini, A. Cavazzini, D.S. Bell, F. Gasparrini, J. Chromatogr. A, 1427 (2016) 55–68.
[2] O.H. Ismail, M. Antonelli, A. Ciogli, C. Villani, A. Cavazzini, M. Catani, F. Gasparrini, J. Chromatogr. A, 1520 (2017) 91–102
[3] O.H. Ismail, M. Antonelli, A. Ciogli, M. De Martino, M. Catani, C. Villani, A. Cavazzini, M. Ye, D.S. Bell, F. Gasparrini, J. Chromatogr. A., 1576 (2018), 42-50
Characterization and applications in seconds time scale of new totally porous sub-2micron CSPs: brush-type and macrocyclic selectors.
No full textOver the last ten years, the technological progress has led to the development of stationary phases on ever smaller silica particles and instruments (UHPLC/UHPSFC) with a reduced extra-column volume able to reach very high pressure. These innovations allow higher efficiencies, resolutions and permit to reduce the analysis time and the eluent consumption. For these reasons also chiral stationary phases (CSPs) are moving to sub-2μm particles diameter. This talk concerns the development of two different sub-2μm CSPs based on the WhelkO-1[1] and on the teicoplanin selectors[2]. The first selector was covalently bonded on fully porous 1.8 μm Kromasil and the second one on totally porous and monodispersed 1.9 μm Titan silica particles. Both CSPs were packed in columns with an I.D. of 4.6 mm and different lengths, from 10 cm down to 1 cm, the latter geometry permitting very short analysis time. The UHPLC columns packed with the WhelkO-1-CSP were evaluated using normal phase and supercritical fluid eluents. Kinetic performances were estimated using trans-stilbene oxide as a probe, and resulted in efficiencies up to 250’000 plates/m under normal phase conditions. To evaluate the thermodynamic performances a large library screening[3] was performed under sub-critical fluid conditions: in one working day, 81 out of 129 randomly collected racemates were resolved under identical eluting conditions. The new UHPC-Titan120-Chirobiotic-TZWIT-1.9 showed a broad field of application in different environments (reversed phase, polar organic mode, HILIC, sub-critical fluid and normal phase). The thermodynamic performances of the new TEICO-Titan 1.9 μm have been evaluated with several N-protected amino acids, aryloxy acids, pharmaceutical compounds, sulfoxides and phosphine oxides. This CSP frequently showed high enantio-selectivity values: downsizing in column length, from 10-cm down to 1-cm was easily possible maintain high efficiency obtaining baseline separations and providing a considerable reduction of the analysis time. Ultra-fast enantiomeric separations in less than 60 seconds could get a routine in the chiral screening methods.
References
[1] D. Kotoni, A. Ciogli, C. Molinaro, I. D’Acquarica, J. Kocergin, T. Szczerb, H. Ritchie, C. Villani, F. Gasparrini, Anal. Chem., 84 (2012), 6805
[2] Berthod A., Chen X., Kullman J.P., Armstrong D.W., Gasparrini F., D’Acquarica I., Villani C., Carotti A., Anal. Chem. 72 (2000) 1767-1780;
[3] L. Sciascera, O. Ismail, A. Ciogli, D. Kotoni, A. Cavazzini, L. Botta, T. Szczerba, J. Kocergin, C. Villani, F. Gasparrini, JCA, 1383 (2015) 160–16
Teicoplanin Chiral Stationary Phases On 2.0 μm And 2.7 μm Superficially Porous Particles: Chromatographic Evaluation And Comparison With Teicoplanin On 1.9 μm Fully Porous Particles.
No full textFor the first time, a new generation of Chiral Stationary Phases (CSPs) for Ultra-High Performance Chromatography (UHPC) was prepared covalently bonding the teicoplanin (TE_A2) selector on Halo 2.0μm and 2.7μm (90Å, 125m2/g) Superficially Porous silica Particles (SPP) [1]. The new CSPs were compared with the already known UHPC-FPP-Titan-Tzwitt 1.9 CSP based on Fully Porous monodispersed silica Particles [2]. Columns with an internal diameter of 4.6 mm and different lengths (20, 50 and 100 mm) were packed with the three CSPs and characterized in terms of permeability, efficiency, retention and enantioselectivity under HILIC conditions. Van Deemter curves, generated using both achiral and chiral analytes, showed excellent results with more than 310000 plates/m at 1.6 mL/min (thiourea, k’= 0.6), and more than 290000 plates/m at 0.9 mL/min (2-(4-chloro-phenoxy)-propionic acid, 1st eluted enantiomer, k’= 0.8) on the SPP-Halo 2.0μm. The kinetic performance limits of the columns were investigated also through different kinetic plots, that proved the superior potential of the SPP-Halo 2.0μm and FPP-Titan 1.9μm compared to the SPP-Halo 2.7μm particles in the majority of the kinetic plots area, especially in the region of the ultra-fast/ultra-high efficiency separations. For several chiral analytes, the columns packed with SPP-Halo 2.0μm and FPP-Titan 1.9μm CSP were superior, in terms of efficiency, to the columns packed with SPP-Halo 2.7μm, proving the validity of the van Deemter analysis. Furthermore, from the thermodynamic point of view, the SPP-Halo 2.0μm have shown the best resolution power, with Rs values significantly higher than those of the SPP-Halo 2.7μm and FPP-Titan 1.9μm. Lastly Ultra-High speed – Ultra-High Performance applications performed on three 5-cm long columns, using chiral probes and different eluent flow-rate (1.0 – 6.0 mL/min) showed very high efficiency values and the FPP-Titan 1.9μm CSP, and again a lower performance for the columns packed with the SPP-Halo 2.7μm CSP. Considering the high resolution values observed, 2-cm long columns were prepared and used to explore Ultra-High speed – Ultra-High Performance separations in the seconds time regime: the enantiomers of Haloxyfop were resolved in only 3 seconds with a resolution Rs = 2 on the column packed with SPP-Halo 2.0μm CSP, using an eluent flow rate of 8.0 mL/min.
REFERENCES
1. O.H. Ismail, M. Antonelli, A. Ciogli, G. Sestito, D.S Bell, A. Cavazzini, C. Villani, F. Gasparrini, JCA, in preparation
2. O.H. Ismail, A. Ciogli, C. Villani, M. De Martino, M. Pierini, A. Cavazzini, D.S. Bell, F. Gasparrini, JCA, 1427 (2016), 55–6
3,5-Dinitrobenzoyl-9-amino-9-deoxy-9-epiquinine as Pirkle-Anion Exchange Hybrid-Type Chiral Selector in High-Performance Liquid Chromatography
No full textA new chiral stationary phase was designed by
introducing 9-amino-9-deoxy-9-epiquinine, one of the
most versatile organocatalysts in asymmetric synthesis, as
chiral scaffold. The derivatization of its amino group with
the 3,5-dinitrobenzoyl (DNB) fragment provided hydrogen
bonding and π–π donor/acceptor systems in addition to
the quinoline and quinuclidine moieties having two nitrogen
atoms with different basicities. The selector offers
multiple interaction sites in both typical of the Pirkle-type
phases and classical of weak-anion-exchanger phases. The
immobilization step took place through thiol-ene addition
onto 3-mercaptopropyl-silica gel and gave a grafting
density of 180 μmol of chiral selector per gram of silica.
A silica with reduced particle size (Daisogel silica, pore
size 120 Å, particle size 2.5 μm, and specific surface area
343 m2 g−1) has been employed to improve the efficiency
and the speed of separations. The chiral stationary phase
was packed in a small format column (50 × 4.6 mm) that
allowed, by van Deemter analysis, 180,000 plates/m and
approximately 5.1 μm of plate height. The ability of chiral
discrimination was then studied with more than 30 test
compounds using both polar-organic and normal phase
conditions. In polar-organic mode, N-protected amino acids, α-aryloxy carboxylic acids, as well the non-steroidal
anti-inflammatory profens were analyzed. Interesting
results were obtained in normal phase elution, where
the chiral selector behaves like a Pirkle-type stationary
phase. Aryl amides, esterified DNB-amino acids, benzodiazepines,
and binaphthol were well resolved with a very
good peak symmetry and in short analysis time (mainly in
less than 5 min)
An evaluation of the conquests During the reign of Caliph Omar according to Belâzürî and Ibn A?sem
No full textBelâzürî ve İbn A'sem'e Göre Hz. Ömer Dönemi Fetihlerinin Değerlendirilmesi? isimli bu tezde Hz. Ömer'in M.634-644 tarihleri arasında 10 yıllık halifelik döneminde gerçekleştirmiş olduğu fetihler iki ayrı Fütuhat kitabına göre incelenmiştir. Belâzüri'nin, fütûhât eserleri arasında yaygın olarak bilinen ?Fütûhu'l-Büldân? adlı eserinde Hz. Ömer döneminde gerçekleşen fetihleri çok ayrıntılı bir şekilde ele aldığı tespit edilmiştir. Eserde fetihlerin gerçekleşme şekilleri, yapılan fetihlerin sonuçlarına göre vergi sistemi, dönemin sosyal yapısı, devletin idarî yapısı, imâr ve iskân faaliyetleri ve benzer konular detaylı bir şekilde ele alınmıştır. Fütûhât kitaplarından birisi olan İbn A'sem'in ?el-Fütûh? adlı eserinde de Hz. Ömer dönemi fetihleri farklı yönleriyle ele alınmıştır. İbn A'sem fetihleri anlatırken şahıslar arasındaki diyaloglara, devlet erkânı arasındaki mektup yazışmalarına geniş yer vermiştir. Ayrıca İbn A'sem tarihçiler tarafından Şiî eğimli olarak değerlendirilmiştir. Böylece Hz. Ömer dönemi fetihleri bu iki eser arasındaki benzer ve farklı yönler ortaya konularak değerlendirilmiştir.In this thesis under the title ?An Evaluation of the Conquests During the Reign of Caliph Omar according to Belâzürî and Ibn A?sem?, Caliph Omar?s conquests during his ten-year caliphate between AD 634-644 has been examined according to two different ?Fütuhât? (plr. of conquest) sources. In Belâzüri?s book which is called ?Fütûhu?l-Büldân? which is widely known among fütûhât sources detailed accounts of the conquests during the reign of Caliph Omar could easily be found. In the source, methods of conquests, tax systems established after conquests, social structure of the time, administrative system of the state, public improvements and settlement activities and similar subjects is to be analysed in a detailed way. In Ibn A?sem?s book which is called ?el-Fütûh? which is one of the fütûhât sources, too, different aspects of the conquests during Omar?s caliphate is to be dealt with. Explaining the conquests, Ibn A?sem gives wide place to dialogues between different figures and correspondance between statesmen of the period. Furthermore, historians agree that Ibn A?sem had a tendency toward Shiism. Therefore,emphasizing similar and different aspects between the two sources the conquests in the time of Caliph Omar is to be examined
Ecological assessment and diversity of woody plants in plantations of frankincense trees (Boswellia papyrifera (Del.) Hochst.) in AlGerri Forest, Blue Nile State, Sudan
No full textهدفت هذه الدراسة إلى تقييم تنوع أنواع الشجيرات والأشجار داخل مزارع اشجار اللبان (Boswellia papyrifera (Del.) Hochst.) في منطقة القري بولاية النيل الأزرق. 18 نمازج دائرية منتظمة حددت لاخذ و تسجيل البيانات تبلغ مساحتة الواحد منها 0.1 هكتار. (نصف القطر = 17.84) مع مسافات تباعد تبلغ 100 متر بين كل نموزج و الاخر، تم استخدامها لجمع البيانات. تم تحديد ما مجموعه 13 نوعًا خشبيًا تنتمي إلى 7 عائلات في مجموعتين من مزارع اشجار اللبان. ساد نوع اشجار اللبان (Boswellia papyrifera) على الأنواع الخشبية في جميع مجتمعات الغطاء النباتي، وتليها انواع الهبيل (Combretum hartmannianum) و الطلح (Acacia seya). كان مؤشرا التنوع في شانون (H) للمجتمع (1) والمجتمع (2) 0.328 و 0.429 على التوالي. كانت قيم مؤشر Pielous Evenness (E) في المجتمع (1) المجتمع (2) 0.344 و 0.429 على التوالي. كثافة المجتمع (1) والمجتمع (2) 609.1 و 309.08 نبات / هكتار. على التوالى. أظهر توزيع الأنواع الخشبية أن 61.54٪ من الأنواع تتواجد في تجمعات في توزيعها و 38.46٪ من الأنواع موزعة عشوائياً. تم استخدام التحليل العنقودي المستند إلى الرابط الفردي Bray-Curtis لتقييم التشابه بين تكوين الأنواع الخشبية عبر 18 نموزج عينة.This study was aimed to evaluate the diversity of shrub and tree species growing under Boswellia papyrifera tree plantation of AlGerri forest reserve in Blue Nile State. 18 systematic circular sample plots of 0.1 ha. (Radius = 17.84) with intervals of 100 m between each plot were used to collect data. A total of 13 woody species belonging to 7 families were determined in two Boswellia papyrifera plantation communities. Boswellia papyrifera dominated the woody species in all vegetation communities, followed by Combretum hartmannianum and Vachellia seyal. The Shannon diversity indexes (H) of community number one and community number two were 0.328 and 0.429 respectively. Pielous Evenness index (E) values in both communities were 0.344 and 0.429 respectively. The density of both communities was 609.1 and 309.08 plant/ha. respectively. The distribution of woody species showed that 61.54% of species were aggregated and 38.46% of species were randomly distributed. Cluster analysis based on the Bray-Curtis single linkage was used to assess the similarity between woody species composition across the 18 sampled plots
L'avventura editoriale della letteratura albanese in Italia: il caso di Ismail Kadare
No full textThe paper reconstructs the arduous journey made by Ismail Kadare's fiction from the early 1970s to the present day, focusing attention on various quest-ions that regard the translation of Kadare's work into over 40 languages. The analysis focuses in particular on the mediation of French in translations of his work and on Kadare's reception in Italy. In addition to providing a detailed account of the works translated so far, the author traces the possible path for future translations, highlighting the gaps in Italian versions of his works and the complexity of the latest authorial versions. Keywords: Ismail Kadare; Italian translations; French mediation; reception
Intern experience at Honeywell, Inc., Large Information Systems Division: an internship report
No full textIncludes author's vita"Submitted to the College of Engineering of Texas A&M University in partial
fulfillment of the requirement for the degree of Doctor of Engineering."Includes bibliographical references (leaves 169-173)This report describes the author's internship assignment at Honeywell
Inc. - Large Information Systems Division from January, 1982 through August, 1982. The purpose
of the assignment was to fulfill the internship requirements of the Doctor of Engineering
Program. During the internship, the author held the position of VLSI design engineer, where he
worked on a predefined project. The project's objective was to evaluate how circuit designs
based on an advanced CMOS process, can be applied to hardware products at LISD. The internship
allowed the author to successfully apply the MOS circuit design training, which ws developed
at Texas A&M, to an industrial project. In addition, involvement in different activities
and exposure to the various problems not encountered in academia, made this internship an
invaluable experience
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