Анализ методов вибродиагностики металлорежущих станков

Цель работы - выработка рекомендаций по применению методов вибродиагностики металлорежущих станков в конкретной задаче. Объект исследования - методы и комплексы вибродиагностики металлорежущих станков. Предмет исследования – систематизация и обобщение методов вибродиагностики металлорежущих станков. Актуальность - отсутствие простой для реализации методики виброиспытаний. В процессе работы были рассмотрены различные методы вибродиагностики металлорежущих станков, сделаны предложения по применению методов вибродиагностики металлорежущих станков в каждой конкретной задаче, создана универсальная методика проведения вибродиагностики металлорежущих станков диагностическим комплексом "Виброрегистратор-М2".The aim of the work is to develop recommendations on the application of vibration diagnostics methods for metal-cutting machine tools in a specific task. The object of research is methods and complexes of vibration diagnostics of metal cutting machines. The subject of the study is the systematization and generalization of methods of vibration diagnostics of metal-cutting machines. Actuality is the absence of a simple vibration testing technique. In the course of the work various methods of vibration diagnostics of metal cutting machines were considered, suggestions were made on the application of vibration diagnostics methods for metal cutting machines in each specific task, a universal technique for performing vibration diagnostics of metal cutting machines with the Vibroregistrator-M2

Anomalie cardiovascolari in pazienti con malattia renale policistica autosomica dominante

La malattia autosomica dominante policistica renale (ADPKD) è la malattia genetica più comune in nefrologia. Due geni sono stati implicati nello sviluppo della malattia: PKD1 sul cromosoma 16 (85%) e PKD2 sul cromosoma 4 (15%). La ADPKD è clinicamente caratterizzata da coinvolgimento renale ed extrarenale espresso con la comparsa di manifestazioni cistiche e non cistiche. Dal momento che le complicanze cardiovascolari sono la principale causa di morbilità e mortalità, questa revisione si propone di analizzare il coinvolgimento cardiaco e vascolare in ADPKD. L'ipertensione è uno dei sintomi più frequenti e comune e si verifica in circa il 60% dei pazienti prima della comparsa di disfunzione renale. L'effetto dell'ipertensione sulla progressione verso stadi terminali della malattia renale, rende tale fattore di rischio uno dei più importanti e potenzialmente trattabili in ADPKD. L'ipertrofia ventricolare sinistra, spesso rilevata in questi pazienti, rappresenta un altro importante fattore di rischio indipendente per morbilità e mortalità cardiovascolare nella ADPKD. Altre anomalie come la disfunzione diastolica biventricolare, la disfunzione endoteliale e l'aumento dello spessore intima-media carotideo sono presenti anche in giovani pazienti con ADPKD con normale pressione sanguigna e la funzione renale ben conservata. Gli aneurismi intracranici, quelli extracranici e i difetti valvolari cardiaci sono altre manifestazioni cardiovascolari di comune riscontro nei pazienti con ADPKD. Il trattamento precoce dell'ipertensione mediante l'uso di agenti bloccanti del sistema renina-angiotensina-aldosterone potrebbe svolgere un effetto nefroprotettivo e ridurre l'insorgenza di complicanze cardiovascolari nei pazienti con ADPKD

Synthetic strategies of new molecular paramagnetic mechanically-interlocked complexes

Supramolecular chemistry is a multidisciplinary field which impinges on other disciplines, focusing on the systems made up of a discrete number of assembled molecular subunits. The forces responsible for the spatial organization are intermolecular reversible interactions. The supramolecular architectures I was interested in are Rotaxanes, mechanically-interlocked architectures consisting of a "dumbbell shaped molecule", threaded through a "macrocycle" where the stoppers at the end of the dumbbell prevent disassociation of components and catenanes, two or more interlocked macrocycles which cannot be separated without breaking the covalent bonds. The aim is to introduce one or more paramagnetic units to use the ESR spectroscopy to investigate complexation properties of these systems cause this technique works in the same time scale of supramolecular assemblies. Chapter 1 underlines the main concepts upon which supramolecular chemistry is based, clarifying the nature of supramolecular interactions and the principles of host-guest chemistry. In chapter 2 it is pointed out the use of ESR spectroscopy to investigate the properties of organic non-covalent assemblies in liquid solution by spin labels and spin probes. The chapter 3 deals with the synthesis of a new class of p-electron-deficient tetracationic cyclophane ring, carrying one or two paramagnetic side-arms based on 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) moiety. In the chapter 4, the Huisgen 1,3-dipolar cycloaddition is exploited to synthesize rotaxanes having paramagnetic cyclodextrins as wheels. In the chapter 5, the catalysis of Huisgen’s cycloaddition by CB[6] is exploited to synthesize paramagnetic CB[6]-based [3]-rotaxanes. In the chapter 6 I reported the first preliminary studies of Actinoid series as a new class of templates in catenanes’ synthesis. Being f-block elements, so having the property of expanding the valence state, they constitute promising candidates as chemical templates offering the possibility to create a complex with coordination number beyond 6

Kinetic control of the direction of inclusion of nitroxide radicals into cyclodextrins

N-benzyl-tert-butyl nitroxide derivatives substituted at the aromatic ring form host-guest inclusion complexes with beta-and gamma-cyclodextrin. They were employed as probes to assess substituent effects on the geometry of the complex and on the kinetics of this complexation by combining EPR and (HNMR)-H-1 dat

Synthesis and characterization of spin-labelled [2]rotaxanes containing tetrathiafulvalene and 1,5-dioxynaphthalene molecular stations

The central component of one of the most studied programmable molecular switches reported by Stoddart and Heath is a [2]rotaxane, which consists of a cyclobis(paraquat-p-phenylene) shuttle (CBPQT4+)(PF6 12)4 (the ring) encircling a finger and moving between two molecular stations, tetrathiafulvalene (TTF) and 1,5-dioxynaphthalene (DNP). In order to employ ESR spectroscopy for understanding the mechanism of this switch, we report here the synthesis and characterization of [2]rotaxanes having persistent nitroxide radicals as the stopper units and TTF or DNP as molecular stations. Isolation of the rotaxanes was successful when bulky nitroxide radicals containing cyclohexyl substituents at 2 and 6 positions of the piperidine-N-oxyl ring were used as terminal stoppers

Unraveling Unidirectional Threading of α‑Cyclodextrin in a [2]Rotaxane through Spin Labeling Approach

We present here the results of a CW-ESR investigation of a double spin labeled α-cyclodextrin-based [2]­rotaxane that is characterized by the presence of nitroxide labels both at the wheel and at the dumbbell. This was accomplished by synthesizing a spin labeled α-CD (the wheel) that was mechanically blocked on a thread containing a nitroxide unit by a Cu­(I) catalyzed azide–alkyne cycloaddition (CuAAC). Both ESI-MS analysis and NMR spectroscopy were used to provide evidence of the threading processes. Because of the unsymmetrical structure of both the wheel and the axle, two different geometrical isomers could be predicted on the basis of the orientation of the CD along the thread. By combining molecular dynamic calculations and information extracted from the CW-ESR spectra, we were able to determine the geometrical nature of the isomer that was isolated as the only species. The ESR spectra showed <i>J</i>-coupling between the two mechanically connected nitroxide units and were analyzed by a model assuming three main molecular states. The intramolecular noncovalent nature of spin exchange was confirmed by reversibly switching the magnetic interaction on–off by changing the pH of the solution in the presence of a competing macrocyclic host

Renal Transplants from Older Deceased Donors: Use of Preimplantation Biopsy and Differential Allocation to Dual or Single Kidney Transplant according to Histological Score Has No Advantages over Allocation to Single Kidney Transplant by Simple Clinical Indication

Background. Grafts from elderly donors (ECD) are increasingly allocated to single (SKT) or dual (DKT) kidney transplantation according to biopsy score. Indications and benefits of either procedure lack universal agreement. Methods. A total of 302 ECD-transplants in period from Jan 1, 2000, to Dec 31, 2015, were allocated to SKT (SKTpre) on clinical grounds alone (before Dec 2010, pre-DKT era, n=170) or according to a clinical-histological protocol (after Dec 2010, DKT era, n=132) to DKT (n=48), SKT biopsy-based protocol (“high-risk”, SKThr, n=51), or SKT clinically based protocol (“low-risk”, SKTlr, n=33). Graft and patient survival were compared between the two periods and between different transplant categories. Results. Graft and overall survival in recipients from ECD in pre-DKT and DKT era did not differ (5-year graft survival 87.7% and 84.2%, resp.); equal survival in the 2 ECD periods was shown in both donor age ranges of 60–69 and >70-years, and in low-risk or high-risk ECD categories. Within the DKT protocol SKThr showed worst graft and overall survival in the 60–69 donor age range; DKT did not result in significantly better outcome than SKT from ECD in either era. One-year posttransplant creatinine clearance in recipients did not differ between any ECD transplant category. At 3 and 5 years after transplantation there were significantly higher total dialysis-free recipient life years from an equal donor number in the pre-DKT era than in the DKT protocol. Conclusions. Use of a biopsy-based protocol to allocate grafts from aged donors to SKT or DKT did not result in better short term graft survival than a clinically based protocol with allocation only to SKT and reduced overall recipient dialysis-free life years in time

Management of an integrated project (Sens-it-iv) to develop in vitro tests to assess sensitisation

Sens-it-iv is an integrated project, funded by European Commission Framework Programme 6, the overall objective of which is to develop in vitro tests and test strategies to be used by the chemical, cosmetic and pharmaceutical industries to assess the risk for potential contact and respiratory sensitisers. Such tests, once formally validated and accepted, will permit the evaluation of the sensitising potential of existing and new chemical entities and the products of the European industries for classification and labelling, as required by the new EU REACH legislation on chemicals, or for the purpose of risk assessment as required by the 7th Amendment to the EU Cosmetics Directive. Sens-it-iv involves 28 partners, representing industries, universities and regulatory bodies, including various institutes in the EU Member States and different competencies, all with the common aim of achieving a final deliverable - increasing the safety of consumer products, whilst reducing animal experimentation. This paper provides an overview of the structure of the project and a detailed description of the organisation of its management