Ontogenetic colour change in Oreophryne ezra (Anura: Microhylidae) reflects an unusual shift from conspicuousness to crypsis but not in toxicity

Ontogenetic colour change (OCC) may signal a switch in defensive strategies across development. Commonly, juveniles use cryptic colours and transition to conspicuous coloration as adults. Extensive theoretical and empirical work suggest such a transition is more likely than the converse. Oreophryne ezra, a newly discovered frog from New Guinea, however, undergoes OCC that belies expectations. We investigated the notion juveniles are aposematic while the adults use crypsis. We quantified the extent of conspicuousness of O. ezra across life stages using spectrophotometry and models of avian vision; and analysed skin extracts for the presence of toxic alkaloids. As predicted, the juvenile colour patterns were estimated to be conspicuous to likely predators against the frogs natural viewing backgrounds, while adults consistently fell below the threshold of discriminability. However, we discovered no alkaloids in either juveniles or adults. This suggests the juveniles use alternative defensive chemicals, or the colour pattern has an alternative origin – to which we offer the hypothesis that juvenile frogs may be Batesian mimics of a synoptic species of weevil. This study highlights the potential for this system, and others like it, to inform our understanding of the adaptive significance of OCC and the selective drivers for different anti-predatory strategies

Contact between the components of a knee prosthesis: numerical and experimental study

The aim of this work is the analysis of the contact area in a knee prosthesis using two different approaches. In particular, the interface between the femoral component and the polyethylene insert has been studied both numerically and experimentally. The interest in studying the contact area is related to the fact that the wear of the polyethylene insert, due to the high contact pressures, represents one of the major causes of failure of the total knee prosthesis. The possibility to evaluate the contact area at different loads and mutual position between femur and tibia is, therefore, of fundamental importance to study the service life of a prosthesis and to improve its performance. The finite element numerical approach has required the acquisition, through reverse engineering, and CAD modelling of the prosthetic components. Then the FEM simulations have been developed considering two different load conditions. In order to compare the calculated data, the same load configurations have been used for experimental tests based on ultrasonic method. In this case, some preliminary tests were required to calibrate the system depending on the particular characteristics of materials, geometries and surface finish of the prosthesis.The results show a good correlation between the data obtained with the two different approaches and, consequently, a good level of reliability of the procedures developed for the numerical and experimental evaluation of the contact area. The numerical procedure can be used to determine the area for different angles and loads, but especially in the design phase. The ultrasonic technique can be used to validate the numerical data

Sequestered Alkaloid Defenses in the Dendrobatid Poison Frog Oophaga pumilio Provide Variable Protection from Microbial Pathogens

Most amphibians produce their own defensive chemicals; however, poison frogs sequester their alkaloid-based defenses from dietary arthropods. Alkaloids function as a defense against predators, and certain types appear to inhibit microbial growth. Alkaloid defenses vary considerably among populations of poison frogs, reflecting geographic differences in availability of dietary arthropods. Consequently, environmentally driven differences in frog defenses may have significant implications regarding their protection against pathogens. While natural alkaloid mixtures in dendrobatid poison frogs have recently been shown to inhibit growth of non-pathogenic microbes, no studies have examined the effectiveness of alkaloids against microbes that infect these frogs. Herein, we examined how alkaloid defenses in the dendrobatid poison frog, Oophaga pumilio, affect growth of the known anuran pathogens Aeromonas hydrophila and Klebsiella pneumoniae. Frogs were collected from five locations throughout Costa Rica that are known to vary in their alkaloid profiles. Alkaloids were isolated from individual skins, and extracts were assayed against both pathogens. Microbe subcultures were inoculated with extracted alkaloids to create dose-response curves. Subsequent spectrophotometry and cell counting assays were used to assess growth inhibition. GC-MS was used to characterize and quantify alkaloids in frog extracts, and our results suggest that variation in alkaloid defenses lead to differences in inhibition of these pathogens. The present study provides the first evidence that alkaloid variation in a dendrobatid poison frog is associated with differences in inhibition of anuran pathogens, and offers further support that alkaloid defenses in poison frogs confer protection against both pathogens and predators

Contact between the components of a knee prosthesis: numerical and experimental study

The aim of this work is the analysis of the contact area in a knee prosthesis using two different approaches. In particular, the interface between the femoral component and the polyethylene insert has been studied both numerically and experimentally. The interest in studying the contact area is related to the fact that the wear of the polyethylene insert, due to the high contact pressures, represents one of the major causes of failure of the total knee prosthesis. The possibility to evaluate the contact area at different loads and mutual position between femur and tibia is, therefore, of fundamental importance to study the service life of a prosthesis and to improve its performance. The finite element numerical approach has required the acquisition, through reverse engineering, and CAD modelling of the prosthetic components. Then the FEM simulations have been developed considering two different load conditions. In order to compare the calculated data, the same load configurations have been used for experimental tests based on ultrasonic method. In this case, some preliminary tests were required to calibrate the system depending on the particular characteristics of materials, geometries and surface finish of the prosthesis.The results show a good correlation between the data obtained with the two different approaches and, consequently, a good level of reliability of the procedures developed for the numerical and experimental evaluation of the contact area. The numerical procedure can be used to determine the area for different angles and loads, but especially in the design phase. The ultrasonic technique can be used to validate the numerical data

Improving sustainable mobility in university campuses. The case study of Sapienza University

The pursue of sustainable mobility is one of the greatest environmental challenges nowadays. It requires a people mind shift, where the use of private vehicles give way to different modes of public transport like buses, bicycles, car sharing, electric cars, and walking lanes. This new call to make mobility sustainable has already been undertaken by policymakers and public managers in many urban contexts around the world, as well as, more recently, by the managers of university systems. The paper shows the work developed in 2018 for the Sapienza Sustainable University Mobility Plan (SUMP). The study stems from the need to understand and improve, in the sustainability direction, modes of travel for the students and staff of one of the oldest universities in the world, and one of the largest in Europe (112,142 students enrolled and 23,101 between academic staff and no academic staff), with its premises located in a complex and challenging urban context such as the city of Rome. The SUMP has been developed in two phases. The first one investigated travel patterns and the reasons for the modal shift and highlighted the main issues. The second phase defined strategies and interventions to be implemented in the short, medium, and long term to make students and staff's mobility more environmentally sustainable. The methodology used in the fact-finding stage was the online survey that was carried out through the use of a diversified questionnaire for staff and students of the University. The sample of students who participated in the survey amounted to 14,719 units, while the sample of faculty and staff was 9,403. The main questionnaire outcomes showed that the attitudes recorded were largely different between faculty and staff and students. While for the first ones the choice of private vehicles is the first option (36%), for students public transport is the prevailing preference (78%). According to the critical aspects found in this first stage, the SUMP objectives were defined, leading to the identification of macro-areas of intervention and specific actions. At a policy and strategic level, the attention was focused on the guidelines issued by the United Nations, the European Commission, and the Network of Universities for Sustainable Development, of which Sapienza University is a member. For this reason, the identification of strategies and interventions results from the combination of the first phase analysis, the Sapienza Governance objectives, and the national and international context in which the SUMP was drafted. Five macro-areas of intervention have been identified: Smart Strategies, Pedestrian Mobility, Cycling, Local Public Transport, Private Transport, and for each one specific intervention to be implemented in different time frames have been defined

An update of the evolving epidemic of blaKPC carrying Klebsiella pneumoniae in Sicily, Italy, 2014: Emergence of multiple Non-ST258 Clones

Background: In Italy, Klebsiella pneumoniae carbapenemase producing K. pneumoniae (KPC-Kp) strains are highly endemic and KPC producing CC258 is reported as the widely predominating clone. In Palermo, Italy, previous reports have confirmed this pattern. However, recent preliminary findings suggest that an epidemiological change is likely ongoing towards a polyclonal KPC-Kp spread. Here we present the results of molecular typing of 94 carbapenem non susceptible K. pneumoniae isolates detected during 2014 in the three different hospitals in Palermo, Italy. Methods and Results: Ninety-four consecutive, non replicate carbapenem non susceptible isolates were identified in the three largest acute general hospitals in Palermo, Italy, in the six-month period March-August 2014. They were characterized by PCR for β-lactam, aminoglycoside and plasmid mediated fluoroquinolone resistance genetic determinants. The mgrB gene of the colistin resistant isolates was amplified and sequenced. Clonality was assessed by pulsed field gel electrophoresis and multilocus sequence typing. Eight non-CC258 sequence types (STs) were identified accounting for 60% of isolates. In particular, ST307 and ST273 accounted for 29% and 18% of isolates. CC258 isolates were more frequently susceptible to gentamicin and non-CC258 isolates to amikacin. Colistin non susceptibility was found in 42% of isolates. Modifications of mgrB were found in 32 isolates. Conclusions: Concurrent clonal expansion of some STs and lateral transmission of genetic resistance determinants are likely producing a thorough change of the KPC-Kp epidemiology in Palermo, Italy. In our setting mgrB inactivation proved to substantially contribute to colistin resistance. Our findings suggest the need to continuously monitor the KPC-Kp epidemiology and to assess by a nationwide survey the possible shifting towards a polyclonal epidemic

Impact of Candida species colonization and azoles resistance in a neonatal intensive care unit

Background: Candida species are among the top 10 most frequently isolated nosocomial bloodstream pathogens in Europe. In particular, in neonatal intensive care units (NICUs) Candida infections are an emerging concern because of the increasing incidence, the related high morbidity and mortality rates reported. Moreover, the epidemiology of Candida infection rapidly changed in these years leading to the selection of less sensitive strains and species. Surveillance studies are mandatory to identify the local distribution of species, their antifungal susceptibility profiles and the emergence of resistance strains. Material/methods: From December 2012 we performed a cohort prospective surveillance study in our NICU, collecting weekly nasal and rectal swabs. Swabs were placed on Sabouraud agar. Candida growth on agar plates was confirmed by microscopic observation. Furthermore, Candida spp. was identified through Candida chromogenic agar (Candida chromogenic agar, Laboratorios Conda) and API\uae 20C AUX (Biom\ue9rieux). The first isolated non-C.albicans Candida (NCAC) species from colonized patients were tested with the main antifungal agents (YeastOne\uae Y010 Thermo Fisher Scientific) and the obtained MIC values were read according to CLSI. Results: From December 2012 to June 2016 we enrolled 874 neonates and analyzed respectively 2014 nasal and rectal swabs. 20/2014 (0,99%) of nasal swabs and 128/2014 (6,35%) of rectal swabs tested positive for Candida spp. The species distribution is showed in the Graph 1. 89/874 (10,18%) neonates tested positive at least in one swab. 59 isolates of NCAC species were tested with the main antifungal agents. All the tested strains were susceptible to echinocandins and amphotericin B. The susceptibility patterns for azoles are shown in the Table 1. Conclusions: Our study confirm the rule of surveillance in the prevention and control of Candida spp. healthcare related infections especially in an high risk ward such as NICU. In particular, in our NICU fluconazole prophylaxis is administered according to standard protocols from 2009.Antifungal susceptibility testes allowed to identify resistant and mutant strains whom acquired resistance so to obtain both clinical and epidemiological data promptly

An update of the evolving epidemic of blaKPC carrying Klebsiella pneumoniae in Sicily, Italy, 2014: Emergence of multiple Non-ST258 Clones

Background: In Italy, Klebsiella pneumoniae carbapenemase producing K. pneumoniae (KPC-Kp) strains are highly endemic and KPC producing CC258 is reported as the widely predominating clone. In Palermo, Italy, previous reports have confirmed this pattern. However, recent preliminary findings suggest that an epidemiological change is likely ongoing towards a polyclonal KPC-Kp spread. Here we present the results of molecular typing of 94 carbapenem non susceptible K. pneumoniae isolates detected during 2014 in the three different hospitals in Palermo, Italy. Methods and Results: Ninety-four consecutive, non replicate carbapenem non susceptible isolates were identified in the three largest acute general hospitals in Palermo, Italy, in the six-month period March-August 2014. They were characterized by PCR for β-lactam, aminoglycoside and plasmid mediated fluoroquinolone resistance genetic determinants. The mgrB gene of the colistin resistant isolates was amplified and sequenced. Clonality was assessed by pulsed field gel electrophoresis and multilocus sequence typing. Eight non-CC258 sequence types (STs) were identified accounting for 60% of isolates. In particular, ST307 and ST273 accounted for 29% and 18% of isolates. CC258 isolates were more frequently susceptible to gentamicin and non-CC258 isolates to amikacin. Colistin non susceptibility was found in 42% of isolates. Modifications of mgrB were found in 32 isolates. Conclusions: Concurrent clonal expansion of some STs and lateral transmission of genetic resistance determinants are likely producing a thorough change of the KPC-Kp epidemiology in Palermo, Italy. In our setting mgrB inactivation proved to substantially contribute to colistin resistance. Our findings suggest the need to continuously monitor the KPC-Kp epidemiology and to assess by a nationwide survey the possible shifting towards a polyclonal epidemic

TTAS a new stilbene derivative that induces apoptosis in Leishmania infantum.

Leishmania parasites are able to undergo apoptosis (programmed cell death), similarly to mammalian cells. Recently it was demonstrated in vitro the anti-leishmanial effect of some natural and synthetic stilbenoids including resveratrol and piceatannol. In this study we evaluated the Leishmanicidal activity of a pool of stilbene derivatives which had previously shown high apoptotic efficacy against neoplastic cells. All the compounds tested were capable to decrease the parasite viability in a dose-dependent manner. Trans-stilbenes proved to be markedly more effective than cis-isomers. This was different from that observed in tumor cells in which cis-stilbenes were more potent cytotoxic agents. Trans-3,4',5-trimethoxy-3'-amino-stilbene (TTAS) was the most active stilbene showing in Leishmania infantum a LD(50) value of 2.6 μg/mL. In contrast TTAS showed a low toxicity when tested on normal hemopoietic cells. This compound induced apoptosis in parasites by disrupting the mitochondrial membrane potential. Moreover it shows the ability to block Leishmania parasites in G(2)-M phase of cell cycle in agreement with the data obtained by affinity chromatography that identify tubulin as the putative target of TTAS. In conclusion, our results indicate that some stilbene derivatives are highly effective as anti-leishmanial agents and TTAS represents a pro-apoptotic agent in Leishmania parasites that merit further in vivo investigation

Oxidative stress in preterm infants: Overview of current evidence and future prospects

Preterm birth (PTB), defined as parturition prior to 37 weeks of gestation, is the leading cause of morbidity and mortality in the neonatal population. The incidence and severity of complications of prematurity increase with decreasing gestational age and birthweight. The aim of this review study is to select the most current evidence on the role of oxidative stress in the onset of preterm complication prevention strategies and treatment options with pre-clinical and clinical trials. We also provide a literature review of primary and secondary studies on the role of oxidative stress in preterm infants and its eventual treatment in prematurity diseases. We conducted a systematic literature search of the Medline (Pubmed), Scholar, and ClinicalTrials.gov databases, retroactively, over a 7-year period. From an initial 777 articles identified, 25 articles were identified that met the inclusion and exclusion criteria. Of these, there were 11 literature reviews: one prospective cohort study, one experimental study, three case-control studies, three pre-clinical trials, and six clinical trials. Several biomarkers were identified as particularly promising, such as the products of the peroxidation of polyunsaturated fatty acids, those of the oxidation of phenylalanine, and the hydroxyl radicals that can attack the DNA chain. Among the most promising drugs, there are those for the prevention of neurological damage, such as melatonin, retinoid lactoferrin, and vitamin E. The microbiome also has an important role in oxidative stress. In conclusion, the most recent studies show that a strong relationship between oxidative stress and prematurity exists and that, unfortunately, there is still little therapeutic evidence reported in the literature