942 resultados para Longevity


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Objective. To test the hypothesis that the difference in the coefficient of thermal contraction of the veneering porcelain above (˛liquid) and below (˛solid) its Tg plays an important role in stress development during a fast cooling protocol of Y-TZP crowns. Methods. Three-dimensional finite element models of veneered Y-TZP crowns were developed. Heat transfer analyses were conducted with two cooling protocols: slow (group A) and fast (groups B–F). Calculated temperatures as a function of time were used to determine the thermal stresses. Porcelain ˛solid was kept constant while its ˛liquid was varied, creating different ˛/˛solid conditions: 0, 1, 1.5, 2 and 3 (groups B–F, respectively). Maximum ( 1) and minimum ( 3) residual principal stress distributions in the porcelain layer were compared. Results. For the slowly cooled crown, positive 1 were observed in the porcelain, orientated perpendicular to the core–veneer interface (“radial” orientation). Simultaneously, negative 3 were observed within the porcelain, mostly in a hoop orientation (“hoop–arch”). For rapidly cooled crowns, stress patterns varied depending on ˛/˛solid ratios. For groups B and C, the patterns were similar to those found in group A for 1 (“radial”) and 3 (“hoop–arch”). For groups D–F, stress distribution changed significantly, with 1 forming a “hoop-arch” pattern while 3 developed a “radial” pattern. Significance. Hoop tensile stresses generated in the veneering layer during fast cooling protocols due to porcelain high ˛/˛solid ratio will facilitate flaw propagation from the surface toward the core, which negatively affects the potential clinical longevity of a crown.

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The scope of this paper is to describe the work of manual sugarcane harvesters, assessing the nutritional behavior and body composition between the beginning and the end of the harvest. A descriptive longitudinal study was made of harvesters in Piracicaba, São Paulo, Brazil, who answered a socio-demographic questionnaire and authorized measurement of Body Mass Index, Body Fat Percentage and Arm Muscle Circumference at three stages. Creatine kinase on the skeletal isoform, C-reactive protein and plasma urea were measured at the end of the harvest. Thirty male migrant harvesters with ages ranging from 18 to 44 from the Northeast (Ceará) were assessed over a nine-month period. The workers suffered significant body fat and weight loss in the first half of the harvest. Eighteen workers had abnormal levels of creatine kinase and four - out of 24 who had donated blood - had altered urea levels. Sugarcane harvesting work causes weight and body fat loss and gains in the lean body mass index, which suffers wear-out when working on consecutive harvests. It can also cause changes in biochemical markers of chronic systemic inflammation. Further studies will make it possible to comprehend the relationships between stress, wear-out, labor longevity and health in sugarcane harvesting.

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The aim of this study was to find alternatives to reduce the cost of mass production of the South American fruit fly (A. fraterculus) by looking for locally available products as protein source in the diet of adults to replace the imported product without changing the quality parameters. Two yeast from a Brazilian company were evaluated. The quality parameters showed that the imported hydrolyzed yeast used in the adult diet could be perfectly replaced by the local products tested, with a reduction of over 80% of the cost of the diet. The quality of the produced insects remained the same and there were improvements in some quality parameters such as the volume of eggs produced, number of adults flying and longevity under the stress.

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Although sex ratios close to unity are expected in dioecious species, biased sex ratios are common in nature. It is essential to understand causes of skewed sex ratios in situ, as they can lead to mate limitation and have implications for the success of natural populations. Female-skewed sex ratios are commonly observed in copepods in situ. Here we discuss the challenges of copepod sex ratio research and provide a critical review of factors determining copepod sex ratios, focusing on 2 main objectives. The first is a critique of the male predation theory, which is currently the main process thought to be responsible for female-skewed sex ratios. It assumes that males have higher mortality because of increased vulnerability to predation during their search for mates. We show that there is little support for the male predation theory, that sex ratios skewed toward females occur in the absence of predation, that sex ratios are not related to predation pressure, and that where sex-skewed predation does occur, it is biased toward females. Our second objective is to suggest alternative hypotheses regarding the determination of sex ratios. We demonstrate that environmental factors, environmental sex determination and sex change have strong effects on copepod sex ratios, and suggest that differential physiological longevity of males and females may be more important in determining sex ratios than previously thought. We suggest that copepod sex ratios are the result of a mixture of factors.

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Hirst et al. (2013; Mar Ecol Prog Ser 489:297-298) suggest that Gusmão et al. (2013; Mar Ecol Prog Ser 482:279-298) misinterpreted the findings of Hirst et al. (2010; Limnol Oceanogr 55:2193-2206). They restate that the major factors determining sex ratio in pelagic copepods act upon the adult stage, but they place less emphasis on the idea that predation on male copepods is a likely determinant, and highlight the role of physiological longevity. Here we reconsider the data and confirm our position that at present there is limited evidence to support the theory of male-skewed predation. However, we agree that sex determination is governed by a combination of factors, with the relative emphasis being the main point of contention between the 2 parties.

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The present study is part of the EU Integrated Project “GEHA – Genetics of Healthy Aging” (Franceschi C et al., Ann N Y Acad Sci. 1100: 21-45, 2007), whose aim is to identify genes involved in healthy aging and longevity, which allow individuals to survive to advanced age in good cognitive and physical function and in the absence of major age-related diseases. Aims The major aims of this thesis were the following: 1. to outline the recruitment procedure of 90+ Italian siblings performed by the recruiting units of the University of Bologna (UNIBO) and Rome (ISS). The procedures related to the following items necessary to perform the study were described and commented: identification of the eligible area for recruitment, demographic aspects related to the need of getting census lists of 90+siblings, mail and phone contact with 90+ subjects and their families, bioethics aspects of the whole procedure, standardization of the recruitment methodology and set-up of a detailed flow chart to be followed by the European recruitment centres (obtainment of the informed consent form, anonimization of data by using a special code, how to perform the interview, how to collect the blood, how to enter data in the GEHA Phenotypic Data Base hosted at Odense). 2. to provide an overview of the phenotypic characteristics of 90+ Italian siblings recruited by the recruiting units of the University of Bologna (UNIBO) and Rome (ISS). The following items were addressed: socio-demographic characteristics, health status, cognitive assessment, physical conditions (handgrip strength test, chair-stand test, physical ability including ADL, vision and hearing ability, movement ability and doing light housework), life-style information (smoking and drinking habits) and subjective well-being (attitude towards life). Moreover, haematological parameters collected in the 90+ sibpairs as optional parameters by the Bologna and Rome recruiting units were used for a more comprehensive evaluation of the results obtained using the above mentioned phenotypic characteristics reported in the GEHA questionnaire. 3. to assess 90+ Italian siblings as far as their health/functional status is concerned on the basis of three classification methods proposed in previous studies on centenarians, which are based on: • actual functional capabilities (ADL, SMMSE, visual and hearing abilities) (Gondo et al., J Gerontol. 61A (3): 305-310, 2006); • actual functional capabilities and morbidity (ADL, ability to walk, SMMSE, presence of cancer, ictus, renal failure, anaemia, and liver diseases) (Franceschi et al., Aging Clin Exp Res, 12:77-84, 2000); • retrospectively collected data about past history of morbidity and age of disease onset (hypertension, heart disease, diabetes, stroke, cancer, osteopororis, neurological diseases, chronic obstructive pulmonary disease and ocular diseases) (Evert et al., J Gerontol A Biol Sci Med Sci. 58A (3): 232-237, 2003). Firstly these available models to define the health status of long-living subjects were applied to the sample and, since the classifications by Gondo and Franceschi are both based on the present functional status, they were compared in order to better recognize the healthy aging phenotype and to identify the best group of 90+ subjects out of the entire studied population. 4. to investigate the concordance of health and functional status among 90+ siblings in order to divide sibpairs in three categories: the best (both sibs are in good shape), the worst (both sibs are in bad shape) and an intermediate group (one sib is in good shape and the other is in bad shape). Moreover, the evaluation wanted to discover which variables are concordant among siblings; thus, concordant variables could be considered as familiar variables (determined by the environment or by genetics). 5. to perform a survival analysis by using mortality data at 1st January 2009 from the follow-up as the main outcome and selected functional and clinical parameters as explanatory variables. Methods A total of 765 90+ Italian subjects recruited by UNIBO (549 90+ siblings, belonging to 258 families) and ISS (216 90+ siblings, belonging to 106 families) recruiting units are included in the analysis. Each subject was interviewed according to a standardized questionnaire, comprising extensively utilized questions that have been validated in previous European studies on elderly subjects and covering demographic information, life style, living conditions, cognitive status (SMMSE), mood, health status and anthropometric measurements. Moreover, subjects were asked to perform some physical tests (Hand Grip Strength test and Chair Standing test) and a sample of about 24 mL of blood was collected and then processed according to a common protocol for the preparation and storage of DNA aliquots. Results From the analysis the main findings are the following: - a standardized protocol to assess cognitive status, physical performances and health status of European nonagenarian subjects was set up, in respect to ethical requirements, and it is available as a reference for other studies in this field; - GEHA families are enriched in long-living members and extreme survival, and represent an appropriate model for the identification of genes involved in healthy aging and longevity; - two simplified sets of criteria to classify 90+ sibling according to their health status were proposed, as operational tools for distinguishing healthy from non healthy subjects; - cognitive and functional parameters have a major role in categorizing 90+ siblings for the health status; - parameters such as education and good physical abilities (500 metres walking ability, going up and down the stairs ability, high scores at hand grip and chair stand tests) are associated with a good health status (defined as “cognitive unimpairment and absence of disability”); - male nonagenarians show a more homogeneous phenotype than females, and, though far fewer in number, tend to be healthier than females; - in males the good health status is not protective for survival, confirming the male-female health survival paradox; - survival after age 90 was dependent mainly on intact cognitive status and absence of functional disabilities; - haemoglobin and creatinine levels are both associated with longevity; - the most concordant items among 90+ siblings are related to the functional status, indicating that they contain a familiar component. It is still to be investigated at what level this familiar component is determined by genetics or by environment or by the interaction between genetics, environment and chance (and at what level). Conclusions In conclusion, we could state that this study, in accordance with the main objectives of the whole GEHA project, represents one of the first attempt to identify the biological and non biological determinants of successful/unsuccessful aging and longevity. Here, the analysis was performed on 90+ siblings recruited in Northern and Central Italy and it could be used as a reference for others studies in this field on Italian population. Moreover, it contributed to the definition of “successful” and “unsuccessful” aging and categorising a very large cohort of our most elderly subjects into “successful” and “unsuccessful” groups provided an unrivalled opportunity to detect some of the basic genetic/molecular mechanisms which underpin good health as opposed to chronic disability. Discoveries in the topic of the biological determinants of healthy aging represent a real possibility to identify new markers to be utilized for the identification of subgroups of old European citizens having a higher risk to develop age-related diseases and disabilities and to direct major preventive medicine strategies for the new epidemic of chronic disease in the 21st century.

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Background. One of the phenomena observed in human aging is the progressive increase of a systemic inflammatory state, a condition referred to as “inflammaging”, negatively correlated with longevity. A prominent mediator of inflammation is the transcription factor NF-kB, that acts as key transcriptional regulator of many genes coding for pro-inflammatory cytokines. Many different signaling pathways activated by very diverse stimuli converge on NF-kB, resulting in a regulatory network characterized by high complexity. NF-kB signaling has been proposed to be responsible of inflammaging. Scope of this analysis is to provide a wider, systemic picture of such intricate signaling and interaction network: the NF-kB pathway interactome. Methods. The study has been carried out following a workflow for gathering information from literature as well as from several pathway and protein interactions databases, and for integrating and analyzing existing data and the relative reconstructed representations by using the available computational tools. Strong manual intervention has been necessarily used to integrate data from multiple sources into mathematically analyzable networks. The reconstruction of the NF-kB interactome pursued with this approach provides a starting point for a general view of the architecture and for a deeper analysis and understanding of this complex regulatory system. Results. A “core” and a “wider” NF-kB pathway interactome, consisting of 140 and 3146 proteins respectively, were reconstructed and analyzed through a mathematical, graph-theoretical approach. Among other interesting features, the topological characterization of the interactomes shows that a relevant number of interacting proteins are in turn products of genes that are controlled and regulated in their expression exactly by NF-kB transcription factors. These “feedback loops”, not always well-known, deserve deeper investigation since they may have a role in tuning the response and the output consequent to NF-kB pathway initiation, in regulating the intensity of the response, or its homeostasis and balance in order to make the functioning of such critical system more robust and reliable. This integrated view allows to shed light on the functional structure and on some of the crucial nodes of thet NF-kB transcription factors interactome. Conclusion. Framing structure and dynamics of the NF-kB interactome into a wider, systemic picture would be a significant step toward a better understanding of how NF-kB globally regulates diverse gene programs and phenotypes. This study represents a step towards a more complete and integrated view of the NF-kB signaling system.

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In this work we discuss the secondary market for life insurance policies in the United States of America. First, we give an overview of the life settlement market: how it came into existence, its growth prospects and the ethical issues it arises. Secondly, we discuss the characteristics of the different life insurance products present in the market and describe how life settlements are originated. Life settlement transactions tend to be long and complex transactions that require the involvement of a number of parties. Also, a direct investment into life insurance policies is fraught with a number of practical issues and entails risks that are not directly related to longevity. This may reduce the efficiency of a direct investment in physical policies. For these reasons, a synthetic longevity market has evolved. The number of parties involved in a synthetic longevity transaction is typically smaller and the broker-dealer transferring the longevity exposure will be retaining most or all of the risks a physical investment entails. Finally, we describe the main methods used in the market to evaluate life settlement investments and the role of life expectancy providers.

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The intraspecific phylogeography of four European coastal plants, Crithmum maritimum, Halimione portulacoides, Salsola kali and Calystegia soldanella, was inferred from AFLP and ITS data. Only in C. maritimum, H. portulacoides and S. kali, a spatial genetic structure was revealed. The phylogeographic similarities and dissimilarities of these species include: (1) All three have distinct Black/Aegean and Adriatic Sea clusters. (2) Salsola kali and H. portulacoides show a distinct Atlantic/North Sea/Baltic Sea cluster, while Atlantic and eastern Spanish material of C. maritimum clustered together. (3) In the west Mediterranean, only S. kali forms a single cluster, while both H. portulacoides and C. maritimum display a phylogeographic break in the vicinity of the southern French coast. For S. kali, AFLP and ITS data concur in identifying separate Atlantic, east and west Mediterranean clades. All these patterns are postulated to result from both temperature changes during the last glacial and contemporary sea currents. No geographic AFLP structure was revealed in C. soldanella, both at the range-wide and population level. This was attributed to the remarkable seed dispersal ability of this species and possibly its longevity and clonal growth, preserving a random pattern of genetic variation generated by long-distance seed dispersal over long time periods.

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Aedes albopictus (Skuse), comunemente detta Zanzara Tigre, ha invaso, negli ultimi anni, molti paesi, soprattutto in modo passivo attraverso il commercio di pneumatici usati. Questa specie è particolarmente adatta all'applicazione della tecnica dell'insetto sterile (SIT), basata su allevamento massale, sterilizzazione e rilascio in campo di un gran numero di maschi della specie vettrice. I maschi sterili rilasciati devono essere in grado di volare, di disperdersi sul territorio, di sopravvivere, di essere sessualmente attivi abbastanza a lungo per coprire il tempo tra una fase di rilascio e la successiva, di individuare le femmine vergini selvatiche e competere con successo per l'accoppiamento con i maschi selvatici. La dispersione e la sopravvivenza dei maschi di Ae. albopictus allevati in laboratorio, sono state studiate mediante tecniche di marcatura, rilascio e ricattura. Le catture sono state eseguite da tecnici specializzati, in un raggio di 350 m dal sito di rilascio. Gli esperimenti condotti hanno dimostrato che i maschi sono in grado di disperdersi, dal sito di rilascio, per circa 200 m ma la loro longevità in campo è fortemente dipendente dalle condizioni climatiche. In studi di semi-campo e di campo è stato valutato uno speciale dispositivo progettato per essere incluso nella stazione di rilascio dei maschi in grado di fornire loro fonti energetiche per migliorarne le prestazioni. I risultati ottenuti sono stati positivi. Studi di competitività sono stati condotti in tunnel costruiti in un ambiente naturale al fine di validare un protocollo per studi sulla competitività dei maschi in questo modello sperimentale. Maschi irraggiati mediante l'applicazione di raggi gamma alla dose di 30 Gy sono stati messi in competizione con maschi fertili per l'accoppiamento con femmine vergini con diversi rapporti. I risultati ottenuti hanno dimostrato le buone prestazioni e l'affidabilità di questo modello sperimentale rimanendo però irrisolto il problema dell’elevata variabilità.

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Dal 1999 presso il laboratorio del Centro Agricoltura Ambiente “G. Nicoli” a Crevalcore (BO) è in corso una sperimentazione finalizzata a verificare la possibilità di attuare la tecnica del maschio sterile (SIT) in Italia contro Aedes albopictus. Alcuni aspetti per migliorare l’efficienza di questa struttura pilota, oggetto della presente ricerca, sono stati: 1) studio degli effetti di determinati costituenti della dieta larvale a) sullo sviluppo larvale stesso, per individuare intervalli limite di densità larvale e di concentrazione di cibo in cui è possibile lo sviluppo di tale specie, e b) sulla qualità dei maschi adulti ottenuti; 2) la valutazione di attrezzatura per l’allevamento massale e 3) la possibilità di migliorare la dieta larvale mediante integrazione di carboidrati. Dalle prove di valutazione della dieta larvale si è potuto osservare che, per quanto riguarda i parametri larvali, le due diete denominate “IAEA” (1 e 2) sono risultate più efficaci rispetto alla dieta standard “CAA”. Tali diete sono perciò da preferirsi nel loro possibile impiego in biofabbriche per l’allevamento massale. Le prove condotte sugli adulti allevati con le diverse diete hanno suggerito la necessità di valutare una possibile integrazione di componenti per migliorarne la longevità. Risulta altresì opportuno continuare la ricerca per ottimizzare la dieta larvale così da ottenere maschi di elevata qualità. Grazie ai risultati ottenuti dalle prove per valutare l’impiego di attrezzatura massale (vassoi di grandi dimensioni e carrello) si è potuto definire un modello per l’allevamento di Ae. albopictus con parametri standardizzati di densità larvale, dose di dieta, temperatura dell’acqua di allevamento, percentuale di maschi passati al setacciamento e rendimento di allevamento. Prove future saranno necessarie per testare altri componenti della dieta ricchi in carboidrati, quali saccarosio, da aggiungere alla dieta larvale per migliorare le qualità degli adulti ottenuti senza provocare effetti negativi sui parametri dello sviluppo larvale.

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Il dolore non è solo una conseguenza della malattia ma un fattore patogeno che è di per se stesso in grado di perpetuare il danno all’organismo. Il suo trattamento non è quindi solo un atto di umanità ma un contributo ad arrestare la malattia e restituire la salute al paziente. Tra i farmaci più popolari per la terapia del dolore negli animali da affezione si trova la buprenorfina. Questa molecola viene impiegata con successo da anni nel cane e nel gatto per motivi riconducibili, oltre che alla sua efficacia (la sua potenza è diverse volte quella della morfina), alla lunga durata d’azione e alla scarsità degli effetti collaterali. Nonostante l’ampia diffusione e longevità del suo utilizzo, però, sappiamo poco della farmacocinetica di questa molecola negli animali da affezione; i dosaggi clinicamente impiegati sono di fatto estrapolati dagli studi nell’uomo oppure basati su semplici osservazioni degli effetti; i pochi dati farmacocinetici ottenuti nel cane fanno riferimento a singoli boli di dosi che non sempre corrispondono a quelle clinicamente impiegate. Nonostante la buprenorfina trovi il suo principale impiego nelle somministrazioni protratte a lungo (durante il periodo post-operatorio o la degenza ospedaliera) non è mai stato indagato il profilo farmacocinetico della molecola somministrata a boli ripetuti o come infusione continua. Il nostro studio si pone come obiettivo di indagare la farmacocinetica della buprenorfina somministrata come bolo di carico seguito da un’infusione costante a dosaggi considerati clinici in cani sani nel periodo post operatorio. Lo scopo ultimo è quello di sviluppare un protocollo per la somministrazione di questa molecola in modo prolungato in pazienti degenti ed addolorati per poi, in futuro, confrontare la somministrazione come infusione continua con i tradizionali boli ripetuti. Per lo studio sono state utilizzate giovani cagne adulte di taglia media o grande sottoposte ad intervento di ovariectomia.