Search

In the present investigation, a new endeavor has been made to analyze the impact of the secondary process (post-weld heat treatment (PWHT)) as well as Ni addition on the microstructure and mechanical characteristics of welds. Welds between similar joining materials from duplex stainless steels (DSS), as well as super DSS (SDSS), were made by the gas tungsten arc welding (GTAW) process. For DSS, after PWHT with the addition of Ni element, the amount of austenite rises and becomes more uniformly distributed with curved boundaries, while for SDSS, the microstructure mainly consists of intergranular and Widmanstätten austenite. According to the comparison of phase percentages obtained based on both ASTM E1245 and ASTM E562, a good balance between ferrite and austenite phases of joint materials was achieved. X-ray diffraction analyses on both joints revealed that phases are mainly ferrite and austenite with different lattice parameters without evidence of unwanted intermetallic phases. The addition of Ni increases the hardness values of DSS weld metal compared to the base metal due to an increased amount of Widmanstätten austenite and ferrite in the microstructure. The lowest ductility was obtained for the SDSS weld sample with the addition of Ni and PWHT because of the existence of secondary austenite in the weld metal and the Widmanstätten morphology of the austenite. The effect of PWHT on the development of microstructure and mechanical behaviors was more than the effect of nickel powder on weld samples.

Clonal hematopoiesis of indeterminate potential (CHIP), marked by the accumulation of somatic mutations in hematopoietic stem cells, significantly elevates the risk of all-cause mortality, mainly due to cardiovascular events. Therefore, investigating this pathophysiological phenomenon is crucial for understanding cardiovascular aging and enhancing both health span and lifespan. In the present study, we examined samples of subjects enrolled within the angiographically controlled Verona Heart Study (VHS), which provides a robust model for cardiovascular aging, particularly regarding coronary artery disease (CAD). We analyzed 44 older subjects diagnosed with coronary artery disease (CAD) and 42 healthy, sex- and age-matched controls (CAD-FREE). Employing deep sequencing and an amplicon-based approach, we focused on 11 key genetic regions in ASXL1, DNMT3A, IDH1, IDH2, JAK2, PPM1D, SF3B1, SRSF2, TET2, TP53, and U2AF1genes to investigate clonal hematopoiesis. Subjects in the CAD group exhibited a significantly higher variant burden than those in the CAD-FREE group, both in terms of the total number of somatic variants and disruptive variants affecting protein function. This increased mutational load was notably influenced by six specific genetic regions: ASXL1, DNMT3A, IDH2, JAK2, TET2, and U2AF1, which displayed elevated variant rates in the CAD subjects. Moreover, ASXL1, DNMT3A, IDH2, JAK2, SF3B1, TET2, and TP53exhibited substantially higher levels of disruptive variants in the CAD group. In summary, our findings highlight a correlation between clonal hematopoiesis and the accumulation of disruptive variants in specific genomic regions in the VHS cohort, thereby shedding light on their potential role in cardiovascular aging.

Mediterranean diet has been proposed to promote healthy aging, but its effects on aging biomarkers have been poorly investigated. We evaluated the impact of a 1-year Mediterranean-like diet in a pilot study including 120 elderly healthy subjects from the NU-AGE study (60 Italians, 60 Poles) by measuring the changes in their epigenetic age, assessed by Horvath’s clock. We observed a trend towards epigenetic rejuvenation of participants after nutritional intervention. The effect was statistically significant in the group of Polish females and in subjects who were epigenetically older at baseline. A genome-wide association study of epigenetic age changes after the intervention did not return significant (adjusted pvalue < 0.05) loci. However, we identified small-effect alleles (nominal pvalue < 10–4), mapping in genes enriched in pathways related to energy metabolism, regulation of cell cycle, and of immune functions. Together, these findings suggest that Mediterranean diet can promote epigenetic rejuvenation but with country-, sex-, and individual-specific effects, thus highlighting the need for a personalized approach to nutritional interventions.

Claims surrounding exceptional longevity are sometimes disputed or dismissed for lack of credible evidence. Here, we present three DNA methylation-based age estimators (epigenetic clocks) for verifying age claims of centenarians. The three centenarian clocks were developed based on n= 7039 blood and saliva samples from individuals older than 40, including n= 184 samples from centenarians, 122 samples from semi-supercentenarians (aged 105 +), and 25 samples from supercentenarians (aged 110 +). The oldest individual was 115 years old. Our most accurate centenarian clock resulted from applying a neural network model to a training set composed of individuals older than 40. An epigenome-wide association study of age in different age groups revealed that age effects in young individuals (age < 40) are correlated (r= 0.55) with age effects in old individuals (age > 90). We present a chromatin state analysis of age effects in centenarians. The centenarian clocks are expected to be useful for validating claims surrounding exceptional old age.

Epithelial ovarian neoplasms can be divided into three distinct clinicopathological groups: benign, malignant and borderline tumours. Borderline tumours are less aggressive than epithelial carcinomas, with an indolent clinical course and delayed recurrence. However, a subset of these cases can progress to malignancy and relapse, and death from recurrent disease can occasionally occur. Telomerase activation is a critical element in cellular immortalisation and cancer. The enzyme telomerase comprises a catalytic subunit (TERT) expressed in various types of cancers and regulated by promoter methylation mainly in epithelial tumours.

Many physiological processes in the human body follow a 24-h circadian rhythm controlled by the circadian clock system. Light, sensed by retina, is the predominant “zeitgeber” able to synchronize the circadian rhythms to the light-dark cycles. Circadian rhythm dysfunction and sleep disorders have been associated with aging and neurodegenerative diseases including mild cognitive impairment (MCI) and Alzheimer’s disease (AD). In the present study, we aimed at investigating the genetic variability of clock genes in AD patients compared to healthy controls from Italy. We also included a group of Italian centenarians, considered as super-controls in association studies given their extreme phenotype of successful aging. We analyzed the exon sequences of eighty-four genes related to circadian rhythms, and the most significant variants identified in this first discovery phase were further assessed in a larger independent cohort of AD patients by matrix assisted laser desorption/ionization-time of flight mass spectrometry. The results identified a significant association between the rs3027178 polymorphism in the PER1circadian gene with AD, the G allele being protective for AD. Interestingly, rs3027178 showed similar genotypic frequencies among AD patients and centenarians. These results collectively underline the relevance of circadian dysfunction in the predisposition to AD and contribute to the discussion on the role of the relationship between the genetics of age-related diseases and of longevity.

Cadmium (Cd) accumulates with aging and is elevated in long-lived species. Metallothioneins (MTs), small cysteine-rich proteins involved in metal homeostasis and Cd detoxification, are known to be related to longevity. However, the relationship between Cd accumulation, the role of MTs, and aging is currently unclear. Specifically, we do not know if long-lived species evolved an efficient metal stress response by upregulating their MT levels to reduce the toxic effects of environmental pollutants, such as Cd, that accumulate over their longer life span. It is also unknown if the number of MT genes, their expression, or both protect the organisms from potentially damaging effects during aging. To address these questions, we reanalyzed several cross-species studies and obtained data on MT expression and Cd accumulation in long-lived mouse models. We confirmed a relationship between species maximum life span in captive mammals and their Cd content in liver and kidney. We found that although the number of MT genes does not affect longevity, gene expression and protein amount of specific MT paralogs are strongly related to life span in mammals. MT expression rather than gene number may influence the high Cd levels and longevity of some species. In support of this, we found that overexpression of MT-1 accelerated Cd accumulation in mice and that tissue Cd was higher in long-lived mouse strains with high MT expression. We conclude that long-lived species have evolved a more efficient stress response by upregulating the expression of MT genes in presence of Cd, which contributes to elevated tissue Cd levels.

Ecological sensing and inflammation have evolved to ensure optima between organism survival and reproductive success in different and changing environments. At the molecular level, ecological sensing consists of many types of receptors located in different tissues that orchestrate integrated responses (immune, neuroendocrine systems) to external and internal stimuli. This review describes emerging data on taste and chemosensory receptors, proposing them as broad ecological sensors and providing evidence that taste perception is shaped not only according to sense epitopes from nutrients but also in response to highly diverse external and internal stimuli. We apply a biological anthropological approach to examine how ecological sensing has been shaped by these stimuli through human evolution for complex interkingdom communication between a host and pathological and symbiotic bacteria, focusing on population-specific genetic diversity. We then focus on how these sensory receptors play a major role in inflammatory processes that form the basis of many modern common metabolic diseases such as obesity, type 2 diabetes, and aging. The impacts of human niche construction and cultural evolution in shaping environments are described with emphasis on consequent biological responsiveness.

The corrosion behaviour and the influence of nickel and post-weld heat treatment (PWHT) on the susceptibility to corrosion in welded duplex stainless steels were investigated. After PWHT, the amount of nickel for the weld region increases resulting in the generation of austenite and consequently, helping to obtain a favourable ferrite-to-austenite ratio. Comparing the experimental outcomes, it is noticed that the pits initiate and propagate in HAZ indicating this area is more susceptible to corrosion resistance compared to the fusion zone. The pitting resistance equivalent number alone is not sufficient reason to study the complex corrosion phenomenon, and the influence of other parameters namely microstructural evolution on the breakdown of passivity by pitting and the existence of intermetallic phases should be determined together.

The present investigation studies the impact of post-weld heat treatment (PWHT) on the microstructure and mechanical characteristics of joints made by gas tungsten arc welding between duplex stainless steel and super-duplex stainless steel specimens. The PWHT process was considered at 1100 °C for 10 minutes followed by water quenching on UNS S32304 and UNS S32750 materials. Scanning electron microscopy, optical microscopy, X-ray diffractometry (XRD), and energy dispersive X-ray analyses have been applied in microstructure evolution, including recognizing local chemical contents and elemental distribution. To analyze the mechanical characteristics of samples, tensile and hardness tests were performed. It was shown that after applying PWHT, the morphology of the austenite varied becoming mostly intergranular/spheroidal in shape, accompanied by an improvement in the percentages of austenite. This investigation indicates the PWHT results in restoring an equal percentage of both phases. The phase percentages, based on both ASTM E1245 and ASTM E562, show a good agreement between the austenite and ferrite phases of weld materials. According to XRD, the phases are mainly ferrite and austenite with different lattice parameters with no evidence of unwanted intermetallic phases. It was concluded that the PWHT process plays a crucial role in the ductility of joint specimens due to the phase balance between austenite and ferrite.

Current literature agrees on the notion that efficient DNA repair favors longevity across evolution. The DNA damage response machinery activates inflammation and type I interferon signaling. Both pathways play an acknowledged role in the pathogenesis of a variety of age-related diseases and are expected to be detrimental for human longevity. Here, we report on the anti-inflammatory molecular make-up of centenarian’s fibroblasts (low levels of IL-6, type 1 interferon beta, and pro-inflammatory microRNAs), which is coupled with low level of DNA damage (measured by comet assay and histone-2AX activation) and preserved telomere length. In the same cells, high levels of the RNAseH2C enzyme subunit and low amounts of RNAseH2 substrates, i.e. cytoplasmic RNA:DNA hybrids are present. Moreover, RNAseH2C locus is hypo-methylated and RNAseH2C knock-down up-regulates IL-6 and type 1 interferon beta in centenarian’s fibroblasts. Interestingly, RNAseH2C locus is hyper-methylated in vitro senescent cells and in tissues from atherosclerotic plaques and breast tumors. Finally, extracellular vesicles from centenarian’s cells up-regulate RNAseH2C expression and dampen the pro-inflammatory phenotype of fibroblasts, myeloid, and cancer cells. These data suggest that centenarians are endowed with restrained DNA damage-induced inflammatory response, that may facilitate their escape from the deleterious effects of age-related chronic inflammation.

The term “street furniture” includes numerous elements (e.g. street lamps, benches, fountains, gazebos) easing city life, complementing architecture and contributing to decorate urban areas. Despite the massive presence of street furniture in the urban environment, the knowledge about its evolution through the centuries is frequently ignored or neglected. This study analyses the main metallurgical features of twenty cast iron metalworks dating back to the 19th and early 20th centuries manufactured in cast iron foundries mainly located in Italy, France and England. The experimental activity was carried out in collaboration with “Fondazione Neri – Museo Italiano della Ghisa” (Longiano, FC, Italy).The microstructure was determined by means of optical microscopy (OM), whereas the semi-quantitative chemical composition was evaluated through scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS).The experimental results highlight the lack of a shared metallurgical culture in steel industry over the last one hundred and fifty years, since non-uniform microstructural features were observed among the specimens produced in that period in the geographical areas under study.

Thermal analysis is widely used as a prediction tool for the quality of Al alloys before casting. In the present work, the effects of different grain refiners on the characteristic temperatures and on the grain size of α-Al phase were studied by thermal analysis and metallographic investigations. The response of an AlSiMg alloy towards grain refiners, added in form of rods and tabs, was investigated. In foundry practice, the fading phenomenon of grain refiners is well-known but not completely understood. For these reasons, the fading effect of each refiner at 60 minutes and 120 minutes holding times was also studied. Cooling curves and their derivatives were obtained during solidification of the alloys in a metallic crucible. Experimental data indicated the increase of the temperature associated with the nucleation of α-Al dendrites for the grain-refined alloys in comparison to the untreated ones. Simultaneously, a decrease in primary Al growth temperature, that led to the disappearance of the minimum temperature, were observed. Microstructural features revealed that an increase of 6 ÷ 7 °C of the nucleation temperature, compared to the not refined alloy, corresponds to a significant decrease in average grain size.

Ageing and age-related diseases share some basic mechanistic pillars that largely converge on inflammation. During ageing, chronic, sterile, low-grade inflammation — called inflammaging — develops, which contributes to the pathogenesis of age-related diseases. From an evolutionary perspective, a variety of stimuli sustain inflammaging, including pathogens (non-self), endogenous cell debris and misplaced molecules (self) and nutrients and gut microbiota (quasi-self). A limited number of receptors, whose degeneracy allows them to recognize many signals and to activate the innate immune responses, sense these stimuli. In this situation, metaflammation (the metabolic inflammation accompanying metabolic diseases) is thought to be the form of chronic inflammation that is driven by nutrient excess or overnutrition; metaflammation is characterized by the same mechanisms underpinning inflammaging. The gut microbiota has a central role in both metaflammation and inflammaging owing to its ability to release inflammatory products, contribute to circadian rhythms and crosstalk with other organs and systems. We argue that chronic diseases are not only the result of ageing and inflammaging; these diseases also accelerate the ageing process and can be considered a manifestation of accelerated ageing. Finally, we propose the use of new biomarkers (DNA methylation, glycomics, metabolomics and lipidomics) that are capable of assessing biological versus chronological age in metabolic diseases.

One way to improve the mechanical properties of Al–Si alloys is to add chemical modifiers that affect the microstructure of the cast components. Small amounts of Sr cause the modification of the eutectic Si particles from a coarse plate-like morphology into a fine fibrous one. This study sets out to analyse the effects of chemical modification on an Al–7%Si–0.3%Mg foundry alloy treated with Sr, ranging from 62 to 820 ppm. Assessment of modification level was evaluated by both thermal analysis technique and quantitative microstructural investigations. Up to now, little attention has been paid to the role played by microstructural characteristics in evaluating the modification level, which is commonly performed by comparison with standard images. In the present investigation, numerical methods proposed in the literature have been considered in an attempt to understand their effectiveness. The correlation between thermal analysis results and geometrical parameters of eutectic Si particles highlighted the impact of microstructural homogeneity on modification-level evaluation. In addition, the presence of Ca in Sr-based intermetallics has been further investigated by means of scanning electron microscopy combined with energy-dispersive X-ray spectroscopy.

In this study, the effect of aging on the mechanical properties of unmodified A356 aluminium casting alloy with trace additions of Ni or V was investigated. Trace elements were added in concentrations of 600 and 1000 ppm of Ni and V, respectively. Samples from sand and permanent mould castings in as cast and T6 heat-treated conditions were tested. Tensile tests were performed at both room and high temperature (235 °C). Taking into account the results from both testing conditions, Vickers hardness was measured in order to endorse the hypothesis of artificial aging occurring during high temperature tensile tests. In order to study this effect, a series of specimens was aged at 235 °C for different aging times, and aging curves were plotted. The occurrence of static and dynamic aging was evaluated by comparing hardness values of tensile specimens and aged samples, particularly in the range of 5-20 min, as this range corresponds to the time necessary for pre-heating and testing of the tensile samples. A basic correlation between tensile strength and hardness is also given.

In recent years, plasma N-glycans have emerged as biomarkers for health and disease. Here, we studied N-glycomic changes in Down Syndrome (DS). Because of the progeroid phenotype of DS, we focused on the dissection of syndrome- and aging-associated glycomic changes, as well as the interaction thereof. We analyzed the plasma N-glycome of 76 DS persons, 37 siblings (DSS), and 42 mothers (DSM) of DS persons by DNA-sequencer-aided, fluorophore-assisted-carbohydrate-electrophoresis, as well as by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). The results showed an overall decrease of galactosylation and α2,3 sialylation, a concomitant increase of the level of fucosylated N-glycans as well as of monogalactosylated diantennary N-glycans in DS, while the GlycoAgeTest and the ratio of the two core-fucosylated, monogalactosylated diantennary isomers (galactose positioned on α1,6 arm versus α1,3 arm) were the strongest DS discriminators. Hypogalactosylation is a characteristic of both DS and aging of control individuals. A decrease in α2,3-sialylated species is also common to DS and aging of controls. However, regarding to α2,6-sialylated tri- and tetragalactosylated N-glycan species, we found those to be lowered in DS but showed an increase with age in the same persons, while these glycans were not affected by aging in control individuals. In conclusion, we identified specific glycomic changes associated with DS, aging in DS, as well as aging in controls, identifying glycomic features in line with accelerated aging in DS. Notably, our data demonstrate an aging phenotype in DS which only in part overlaps with aging in controls but reveals DS-specificity.

Al matrix composites reinforced by 10 vol.% Al2O3and SiC particles were subjected to dry sliding tests against steel using a slider-on-cylinder tribometer. Damage mechanisms were "micro-machining" of the steel carried out by ceramic particles, plastic deformation and oxidation of the metal matrix, as well as abrasion. The results were discussed on the basis of the third-body wear model.

A new thermal and mechanical treatment, based on a cold-work cycle, able to promote a superplastic behaviour in the IN-718 superalloy is illustrated. The optimum conditions of temperature and strain rate for the best superplastic behaviour of the alloy have been found. The influence of microstructural parameters and the mechanisms involved during the deformation process are discussed through examination of the flow curves at various temperatures and strain rates, and by metallographic analyses.

Memory cells, the ultimate neurobiological substrates of working memory, remain active for several seconds and are most commonly found in prefrontal cortex and higher multisensory areas. However, if correlated activity in “embodied” sensorimotor systems underlies the formation of memory traces, why should memory cells emerge in areas distant from their antecedent activations in sensorimotor areas, thus leading to “disembodiment” (movement away from sensorimotor systems) of memory mechanisms? We modelled the formation of memory circuits in six-area neurocomputational architectures, implementing motor and sensory primary, secondary and higher association areas in frontotemporal cortices along with known between-area neuroanatomical connections. Sensorimotor learning driven by Hebbian neuroplasticity led to formation of cell assemblies distributed across the different areas of the network. These action-perception circuits (APCs) ignited fully when stimulated, thus providing a neural basis for long-term memory (LTM) of sensorimotor information linked by learning. Subsequent to ignition, activity vanished rapidly from APC neurons in sensorimotor areas but persisted in those in multimodal prefrontal and temporal areas. Such persistent activity provides a mechanism for working memory for actions, perceptions and symbols, including short-term phonological and semantic storage. Cell assembly ignition and “disembodied” working memory retreat of activity to multimodal areas are documented in the neurocomputational models' activity dynamics, at the level of single cells, circuits, and cortical areas. Memory disembodiment is explained neuromechanistically by APC formation and structural neuroanatomical features of the model networks, especially the central role of multimodal prefrontal and temporal cortices in bridging between sensory and motor areas. These simulations answer the “where” question of cortical working memory in terms of distributed APCs and their inner structure, which is, in part, determined by neuroanatomical structure. As the neurocomputational model provides a mechanistic explanation of how memory-related “disembodied” neuronal activity emerges in “embodied” APCs, it may be key to solving aspects of the embodiment debate and eventually to a better understanding of cognitive brain functions.

Cancer stem cell survival relies on the activation of inflammatory pathways, which is speculatively triggered by cell autonomous mechanisms or by microenvironmental stimuli. Here, we observed that hypoxic bone marrow stroma–derived transforming growth factor-β 1 promotes the growth of human breast cancer stem cells as mammospheres. The ensuing Slug-dependent serine 139 phosphorylation of the DNA damage sensor H2AX in breast cancer stem cells induces tumor necrosis factor-α and IL-8 mRNAs, whose stability is enhanced by cytoplasmic β-catenin. β-Catenin also up-regulates and binds miR-221, reducing the stability of the miR-221 targets Rad51 and ERα mRNAs. Our data show that the Slug/β-catenin–dependent activation of DNA damage signaling triggered by the hypoxic microenvironment sustains the proinflammatory phenotype of breast cancer stem cells.

Inflamm-aging, that is the age-associated inflammatory status, is considered one of the most striking consequences of immunosenescence, as it is believed to be linked to the majority of age-associated diseases sharing an inflammatory basis. Nevertheless, evidence is emerging that inflamm-aging is at least in part independent from immunological stimuli. Moreover, centenarians who avoided or delayed major inflammatory diseases display markers of inflammation. In this paper we proposed a reappraisal of the concept of inflamm- aging, suggesting that its pathological effects can be independent from the total amount of pro-inflammatory mediators, but they would be rather associated with the anatomical district and type of cells where they are produced and where they primarily act.

Colorectal cancer (CRC) is a major health problem causing significant morbidity and mortality. During the last decade, results from different studies indicate that the pathogenetic mechanisms of CRC encompass tumour microenvironment, emphasizing a tight correlation with aging, inflammation, nutrition, gut microbiome composition and epigenetic modifications. Aging is one of the most important risk factors for the development of a wide range of neoplasies, including CRC, as it represents the general framework in which the tumor environment evolves. Together, these elements likely contribute to the carcinogenic process with specific effects, impacts and roles in the different stages of the tumor progression. CRCs evolve through loops of deregulated inflammatory stimuli which are sustained by DNA damage signaling pathways, dysbiosis of gut microbiota (GM) and epigenetic re-modelling (DNA methylation). To date no studies address those elements simultaneously. The synergic analysis of such parameters could provide new biological insights and effective biomarkers that could have applications in prevention, molecular diagnosis, prognosis and treatment of CRC.

Free nonvascularized phalangeal transfer from a toe to congenitally hypoplastic digits, is an established procedure in the repertoire of digit reconstruction. The hypoplastic digit is frequently flexed, due to shortage of palmar soft tissues. The phalanx must be transferred intact, with a complete periosteal covering. A new technique of incision and dissection is described utilizing a palmar V approach, closed after skin advancement, as a Y. This permits ample visualization of the digital envelope to receive the phalanx, protection under direct vision of the digital bundles, and simultaneous correction of the deficient palmar skin, without tension.

Single nucleotide polymorphisms (SNPs) in double-strand break repair genes may alter DNA repair capacity and, in turn, confer predisposition to leukemia. We analyzed polymorphic variants of DNA repair and detoxification genes in patients with multiple sclerosis (MS) who developed secondary acute promyelocytic leukemia (sAPL), in most cases after treatment with mitoxantrone (MTZ).

Es gibt viele Ansätze zur Korrelation der Kerbschlagarbeit mit Bruchparametern. Die meisten davon liefern empirische oder halbtheoretische Gleichungen, die diesen Zusammenhang belegen.

Associations of Psychosocial and Individual Factors with Three Different Categories of Back Disorder among Nursing Staff: Francesco S. Violante, et al.Alma Mater Studiorum—University of Bologna, Occupational Medicine Unit, Sant’Orsola-Malpighi Hospital, Italy—Although back disorders are a major occupational problem for nursing staff, few studies distinguish different types. By means of a structured questionnaire, we performed a cross-sectional study on the prevalence of diagnosed lumbar disc hernia, chronic low-back pain (LBP) (at least 90 d in the preceding 12 months) and acute LBP (intense pain for at least 1 d) with respect to physical, individual and psychosocial factors among female nurses (n=587), nursing aides (n=228) and head-nurses (n=43) working in a university hospital (95% of the female workforce). Almost all respondents reported known high-risk occupational activities. Overall prevalence of reported back disorders was 44% (acute LBP 19%, chronic LBP 17%, lumbar hernia 8%). On multinomial logistic regression analysis, scoliosis and commonly stress-related psychosomatic symptoms were associated with all three types of back disorder; trauma/ fractures of the spine, pelvis and/or legs and a global work-environment/job-satisfaction score with acute LBP; increasing age with lumbar disc hernia. While confirming the relevance of considering different definitions of back disorder, our data indicate items for investigation in cohort studies. These include: identification of specific risk factors for lumbar hernia; avoidance of possible work-environment risk factors such as hurried execution of different tasks at the same time; and influence on job suitability of underlying spinal pathologies such as scoliosis.

Associations of Psychosocial and Individual Factors with Three Different Categories of Back Disorder among Nursing Staff: Francesco S. Violante, et al.Alma Mater Studiorum—University of Bologna, Occupational Medicine Unit, Sant’Orsola‐Malpighi Hospital, Italy—Although back disorders are a major occupational problem for nursing staff, few studies distinguish different types. By means of a structured questionnaire, we performed a cross‐sectional study on the prevalence of diagnosed lumbar disc hernia, chronic low‐back pain (LBP) (at least 90 d in the preceding 12 months) and acute LBP (intense pain for at least 1 d) with respect to physical, individual and psychosocial factors among female nurses (n=587), nursing aides (n=228) and head‐nurses (n=43) working in a university hospital (95% of the female workforce). Almost all respondents reported known high‐risk occupational activities. Overall prevalence of reported back disorders was 44% (acute LBP 19%, chronic LBP 17%, lumbar hernia 8%). On multinomial logistic regression analysis, scoliosis and commonly stress‐related psychosomatic symptoms were associated with all three types of back disorder; trauma/ fractures of the spine, pelvis and/or legs and a global work‐environment/job‐satisfaction score with acute LBP; increasing age with lumbar disc hernia. While confirming the relevance of considering different definitions of back disorder, our data indicate items for investigation in cohort studies. These include: identification of specific risk factors for lumbar hernia; avoidance of possible work‐environment risk factors such as hurried execution of different tasks at the same time; and influence on job suitability of underlying spinal pathologies such as scoliosis.

High and low-cycle fatigue tests were performed on AA 6061/10%Al₂O_3p, AA 6061/20%Al₂O_3p and AA 2618/20%Al₂O_3p metal matrix composites. All the materials were tested in a peak-aged condition (T6 temper). The fatigue properties were analysed in terms of reinforcement and particle/matrix interface properties; the effect of reinforcement volume fraction and size was also studied. OM, SEM and EDS analyses were performed on the composites. SEM analyses were also carried out on the fracture surfaces of fatigue-tested samples to assess crack nucleation and growth mechanisms. Differences between low and high-cycle fatigue and fracture behaviour were discussed for the tested composites. In the high-cycle fatigue regime, the materials showed better resistance than the corresponding un-reinforced alloys only at low stresses. The composite resistance to the low-cycle fatigue was less satisfactory. In this case, a coarser reinforcement reduced the fatigue life, due to greater tendency toward particle damage on loading.

Orocecal transit time can be studied easily using the hydrogen breath test with lactulose, but the method has some important limitations. The orocecal transit time of 10 patients suffering from irritable bowel syndrome was measured twice, at a one-week interval, by breath test and scintigraphy simultaneously using an aqueous solution of 20 g lactulose containing 74 MBq of [99mTc]DTPA. Abdominal radioactivity and alveolar hydrogen values obtained every 5 min were noted and used to obtain the following: orocecal transit time by the two methods; ileocecal lactulose flow; total and per gram of lactulose hydrogen production; mean hydrogen concentration during the right colon filling; and measurement error of the breath test with respect to the scintigraphy. In the case of the breath test, the orocecal transit time intrapatient reproducibility was better (coefficient of variation =13.5%) when a hydrogen threshold increment of 5 ppm was used; the best correlation with the scintigraphic measurement was observed at this threshold (r=0.90,P<0.001). The breath test overestimated orocecal transit time with the error correlating negatively and significantly with the total hydrogen production and, particularly, the mean hydrogen concentration (r=0.79,P<0.01): for a mean hydrogen concentration of more than 15 ppm, the error was negligible, while within this value there was a noticeable overestimation. To conclude, the lactulose hydrogen breath test is capable of giving an accurate measurement of orocecal transit time if a hydrogen threshold increment of 5 ppm is chosen and if the mean hydrogen concentration in the first 30 min of the right colon filling is taken into account.

The influence of glass fibres on the primary nucleation process, isothermal radial growth rate of spherulites and overall kinetic rate constant of isotactic polypropylene (iPP) has been examined. The polypropylene was also modified by means of acrylic acid (iPP*) in order to improve the adhesion between the matrix and the fibres, and the relative properties were compared with those concerning the composites having as matrix plain MR Moreover the mechanical properties of injection-moulded composites containing iPP and iPP* have been studied. These properties improved on increasing the fibre content. It was found that for the same glass-fibre content better values of the elongation at break and creep are observed in the case of reinforced polypropylenes having as matrix acrylic acid modified polypropylene.

The present work is aimed at studying the impact behaviour of commercially available Aluminium matrix composites, in a temperature interval ranging from 25°C to 200°C. The results of instrumented impact tests and of microstructural and fractographic observations are correlated with the tensile properties of these materials. A description of the phenomena involved (particles cracking, interfacial failure associated to matrix-reinforcement reaction layers, ductile behaviour of the matrix) is given. The effect of testing temperature as well as that of the matrix characteristics are presented and discussed.

The present work is aimed at studying the impact behaviour of commercially available Aluminium matrix composites, in a temperature interval ranging from 25C° to 200°C. The results of instrumented impact tests and of microstructural and fractographic observations are correlated with the tensile properties of these materials. A description of the phenomena involved (particles cracking, interfacial failure associated to matrix-reinforcement reaction layers, ductile behaviour of the matrix) is given. The effect of testing temperature as well as that of the matrix characteristics are presented and discussed.

A sample consisting of about 120 organic rearrangement reactions has been quantified in terms general reaction matrices R̃ expressing electron-flow processes. About two thirds of the reactions considered conform to only two distinct R̃-matrices, 80% to five such schemes. The frequency distribution is qualitatively similar to that found for larger, more randomly chosen, sets of organic reactions. Examples of the various electron-flow processes are given. The bearings of the results on synthesis-planning are discussed.

A sample consisting of 427 one- and multi-step organic name reactions has been classified in terms of a previously determined empirical set of 43 general reaction-matrix types (R), according to procedures outlined originally by UGI et al.14. The resulting distribution of R-matrices is similar to the overall pattern of other random and specialized sample analyses. The metathesis reaction accounts for 60% of all single-step synthetic transformations; subsets consisting of the primary three and ten R-matrices describe some 78% and 93% of the population, respectively. The results represent a valid experimental basis for the mathematical description of the constitution of organic chemistry.

The microstructural and technological characteristics of metal matrix composites can be tailored if the role played by typical reinforcement parameters (type, shape, and volume fraction) is correctly evaluated. The present work used commercially pure Al reinforced with ceramic particles (Al2O3, SiC), manufactured via powder metallurgy and hot extruded. The volume fraction of reinforcement ranged from 5 to 15%. Dry sliding tests were performed on the composites using a fiat on cylinder tribometer and the friction coefficient versus sliding distance was recorded. The counterface was a carbon steel cylinder treated up to a Rockwell hardness of 60 HRC. The microstructure of the worn surfaces of the composites was evaluated via light microscopy, scanning electron microscopy, and transmission electron microscopy. The wear behaviour and microstructural evolution of all materials including the unreinforced matrix, were related to both reinforcement variables and testing conditions. Using wear mechanism mapping, some guidelines for designing and selecting wear resistant composites are suggested.MST/3006

Not Available

The fracture resistence properties of a rod and a plate, both made of 2024 aluminium alloy, are evaluated according to standard and non-standard methods. The materials are tested after heat treatments involving material microstructures different especially as to size and dispersion of the hardening precipitates.

Background. Age-related clonal hematopoiesis of indeterminate potential (CHIP), a relatively common condition in elderly people, has been associated with an increased risk of hematological neoplasms, and, to a greater extent, of overall mortality. Earlier this year, Jaiswal and colleagues have suggested that excess mortality in subjects with CHIP is related to an increased risk of cardiovascular diseases, and provided a convincing model linking TET2mutations to a pro-inflammatory state favoring the development of atherosclerotic plaques.