Laser driven self-assembly of shape-controlled potassium nanoparticles in porous glass

We observe growth of shape-controlled potassium nanoparticles inside a random network of glass nanopores, exposed to low-power laser radiation. Visible laser light plays a dual role: it increases the desorption probability of potassium atoms from the inner glass walls and induces the self-assembly of metastable metallic nanoparticles along the nanopores. By probing the sample transparency and the atomic light-induced desorption flux into the vapour phase, the dynamics of both cluster formation/evaporation and atomic photo-desorption processes are characterized. Results indicate that laser light not only increases the number of nanoparticles embedded in the glass matrix but also influences their structural properties. By properly choosing the laser frequency and the illumination time, we demonstrate that it is possible to tailor the nanoparticles'shape distribution. Furthermore, a deep connection between the macroscopic behaviour of atomic desorption and light-assisted cluster formation is observed. Our results suggest new perspectives for the study of atom/surface interaction as well as an effective tool for the light-controlled reversible growth of nanostructures.Comment: 14 pages,6 figures, http://iopscience.iop.org/1612-202X/11/8/085902

Temporal pattern of Klebsiella pneumoniae carbapenemase (KPC) on surface of an intensive care unit of a large hospital

Background: Carbapenem-resistant Enterobacteriaceae are an increasing cause of healthcare-associated infections worldwide. Patients with infections caused by Klebsiella pneumoniae resistant to carbapenems (KPC) have significant increases in both allcause mortality and 30-day mortality. The aims of this study was to investigate the prevalence of KPC on environmental samples collected during and after an outbreak caused by KPC in an intensive care unit (ICU) of a teaching hospital. Methods: Between 2010 and 2014 we conducted a total of 132 environmental monitoring campaigns from different critical surface of ICU ward in a Teaching Hospital Policlinico Umberto I. Samples were collected on surfaces in patient rooms and health care area. All samples were cultured and K. pneumoniae isolates were identified by standard microbiological techniques. The presumptive colonies were confirmed and tested for antibiotic resistance by an automated system. K. pneumoniae resitant to carbapenems were tested for carbapenemase production by modified Hodge test. Results: A total of 2526 environmental samples were collected from November 2010 to July 2014. Of those, 111 resulted positive for K. pneumoniae while KPC were 95 (85.6% of all K. pneumoniae, 3.8% of total samples). KPC was recovered in all patient rooms with similar proportion (5.1-5.6%) with the exception of patient 6 bed room where it was lower (2.4%). The pathogen was not recovered in rooms dedicated to healthcare personnel and doctors. Among surfaces, the highest proportion of KPC resulted on bedrail (6.8%), more than double than other surfaces. Washbasins had nearly half of samples KPC positive (1.2%). Conclusions: Despite previous studies suggested that environment plays a minor role in the transmission of carbapenem-resistant enterobacteriaceae, our data highlighted that surfaces represents a significant reservoir for KPC possibly supporting transiently contamination of hands of healthcare workers in our ICU. Our results confirm that KPC are more likely found on surfaces closer to the patient than on those situated further away

Experiences with formal engineering: model-based specification, implementation and testing of a software bus at Neopost

We report on the actual industrial use of formal methods during the development of a software bus. During an internship at Neopost Inc., of 14 weeks, we developed the server component of a software bus, called the XBus, using formal methods during the design, validation and testing phase: we modeled our design of the XBus in the process algebra mCRL2, validated the design using the mCRL2-simulator, and fully automatically tested our implementation with the model-based test tool JTorX. This resulted in a well- tested software bus with a maintainable architecture. Writing the model (mdev), simulating it, and testing the implementation with JTorX only took 17% of the total development time. Moreover, the errors found with model-based testing would have been hard to find with conventional test methods. Thus, we show that formal engineering can be feasible, beneficial and cost-effective.\ud The findings above, reported earlier by us in (Sijtema et al., 2011) [1], were well- received, also in industrially oriented conferences (Ferreira and Romanenko, 2010) [2] and [3]. In this paper, we look back on the case study, and carefully analyze its merits and shortcomings. We reflect on (1) the added benefits of model checking, (2) model completeness and (3) the quality and performance of the test process.\ud Thus, in a second phase, after the internship, we model checked the XBus protocol—this was not done in [1] since the Neopost business process required a working implementation after 14 weeks. We used the CADP tool evaluator4 to check the behavioral requirements obtained during the development. Model checking did not uncover errors in model mdev, but revealed that model mdev was neither complete nor optimized: in particular, requirements to the so-called bad weather behavior (exceptions, unexpected inputs, etc.) were missing. Therefore, we created several improved models, checked that we could validate them, and used them to analyze quality and performance of the test process. Model checking was expensive: it took us approx. 4 weeks in total, compared to 3 weeks for the entire model-based testing approach during the internship.\ud In the second phase, we analyzed the quality and performance of the test process, where we looked at both code and model coverage. We found that high code coverage (almost 100%) is in most cases obtained within 1000 test steps and 2 minutes, which matches the fact that the faults in the XBus were discovered within a few minutes.\ud Summarizing, we firmly believe that the formal engineering approach is cost-effective, and produces high quality software products. Model checking does yield significantly better models, but is also costly. Thus, system developers should trade off higher model quality against higher costs

Process-specific cues for recruitment in sedimentary environments: Geochemical signals?

The most biologically and geochemically active marine sediments are characterized by steep chemical gradients within the top centimeters of sediment (Berner, 1980). A common feature of these environments is disruptions of surface sediments by both physical and biotic forces. Growth and mortality rates for new recruits are affected by many of these surface perturbations. At the same time, these disturbances also impose a discontinuity in concentration across the sediment-water interface, and accordingly, a change in surface chemistry. In this paper we present evidence that the cue used by juveniles to distinguish between recently disturbed and undisturbed surfaces may be disruption of geochemical gradients that are typical of nearshore benthic systems. New juveniles exposed to ammonium concentrations typical of disturbed surface sediments exhibit behaviors consistent with rejection of the habitat. Conversely, new juveniles placed onto sediments containing ammonium levels typical of undisturbed surficial sediments rapidly initiate burrowing activity, a sign of acceptability. We also present a numerical model, which assesses the dynamics of small-scale chemical shifts that accompany sediment disruption, to determine (a) what is the magnitude of surface chemistry changes associated with disturbance (i.e. what is the signal strength)? and (b) what are the spatial and temporal scales associated with the return to the undisturbed condition ( recovery )? Model results show that the signal strength, and the return to acceptable conditions, are strongly influenced by the initial gradient. Model predictions of the time required to recover indicate that times to recovery are longer than the interval between disturbance events, but are of the same temporal scale (minutes to hours). Thus, our results suggest that the dynamics of surficial gradients provide a strong signal over appropriate time scales that may reveal the intensity of disturbance and the likelihood of mortality for juveniles. As such, transport-reaction processes which govern porewater concentrations in surficial sediments may also play a role in recruitment processes

Eigenvalue distributions for some correlated complex sample covariance matrices

The distributions of the smallest and largest eigenvalues for the matrix product $Z^\dagger Z$, where $Z$ is an $n \times m$ complex Gaussian matrix with correlations both along rows and down columns, are expressed as $m \times m$ determinants. In the case of correlation along rows, these expressions are computationally more efficient than those involving sums over partitions and Schur polynomials reported recently for the same distributions.Comment: 11 page

Heat shock protein expression in canine malignant mammary tumours.

Background Abnormal levels of Heat Shock Proteins (HSPs) have been observed in many human neoplasms including breast cancer and it has been demonstrated that they have both prognostic and therapeutic implications. In this study, we evaluated immunohistochemical expression of HSPs in normal and neoplastic canine mammary glands and confronted these results with overall survival (OS), in order to understand the role of HSPs in carcinogenesis and to establish their potential prognostic and/or therapeutic value. Methods Immunohistochemical expression of Hsp27, Hsp72, Hsp73 and Hsp90 was evaluated in 3 normal canine mammary glands and 30 malignant mammary tumours (10 in situ carcinomas, 10 invasive carcinomas limited to local structures without identifiable invasion of blood or lymphatic vessels, 10 carcinomas with invasion of blood or lymphatic vessels and/or metastases to regional lymph nodes). A semi-quantitative method was used for the analysis of the results. Results Widespread constitutive expression of Hsp73 and Hsp90 was detected in normal tissue, Hsp72 appeared to be focally distributed and Hsp27 showed a negative to rare weak immunostaining. In mammary tumours, a significant increase in Hsp27 (P < 0.01), Hsp72 (P < 0.05) and Hsp90 (P < 0.01) expression was observed as well as a significant reduction in Hsp73 (P < 0.01) immunoreactivity compared to normal mammary gland tissue. Hsp27 demonstrated a strong positivity in infiltrating tumour cells and metaplastic squamous elements of invasive groups. High Hsp27 expression also appeared to be significantly correlated to a shorter OS (P = 0.00087). Intense immunolabelling of Hsp72 and Hsp73 was frequently detected in infiltrative or inflammatory tumour areas. Hsp90 expression was high in all tumours and, like Hsp73, it also showed an intense positivity in lymphatic emboli. Conclusion These results suggest that Hsp27, Hsp72 and Hsp90 are involved in canine mammary gland carcinogenesis. In addition, Hsp27 appears to be implicated in tumour invasiveness and its high immunodetection in invasive tumours is indicative of a poorer clinical outcome

A structured index describing the ease of disassembly for handcrafted product

Both economic and environmental aspects significantly influence the design process since the early phases of preliminary design. The total Life Cycle Assessment (LCA) and the End of Life (EoL) of products have to be defined in the early design phases too but, for industrial products that are not feasible to automatic production, they are hard issues. However, the EoL of products can be assessed by evaluating the disassembly of joints assembling the product, even when the production process is subject to an important contribute of workmanship. In this paper, a useful method is proposed to analyze the disassembly plant of products, in order to optimize the design process in the early preliminary phases. The method quantitatively evaluates a Disassembly Index that describes the attitude of a product to be disassembled. A case study describes the disassembly attitude of structural subassemblies of a sailboat. In order to test the applicability of the model described to both manual and automated disassembly, a further application of the method is proposed on a Computer CPU. As result, the model demonstrated good sensitiveness to the testing of products quite different for dimensions, number of components, manufacturing processes and, in all cases, it quantified the disassembly easiness with good relevance

Diabetic striatopathy: an updated overview of current knowledge and future perspectives

Purpose: Diabetic striatopathy (DS) is a rare complication of poorly controlled diabetes mellitus (DM), characterized by hyperglycemia associated with chorea/ballism and characteristic reversible basal ganglia abnormalities on computed tomography (CT) and/or magnetic resonance imaging (MRI). We propose a narrative review of the literature on this topic, currently unknown to most, and about which physicians should be aware. We intend to summarize, critically review, and take to mean the evidence on this disorder, describing its typical features. Methods: We searched Pubmed for English-language sources using the following keywords in the title and the abstract: diabetic striatopathy, hyperglycemic non-ketotic hemichorea/hemiballism, chorea/hemichorea associated with non-ketotic hyperglycemia, diabetic hemiballism/hemichorea, chorea, hyperglycemia, and basal ganglia syndrome. We collected scientific articles, including case reports, reviews, systematic reviews, and meta-analyses from the years 1975 to 2023. We eliminated duplicate, non-English language or non-related articles. Results: Older Asian women are more frequently affected. Suddenly or insidiously hemichorea/hemiballism, mainly in the limbs, and high blood glucose with elevated HbA1c in the absence of ketone bodies have been observed. Furthermore, CT striatal hyperdensity and T1-weighted MRI hyperintensity have been observed. DS is often a treatable disease following proper hydration and insulin administration. Histopathological findings are variable, and no comprehensive hypothesis explains the atypical cases reported. Conclusion: DS is a rare neurological manifestation of DM. If adequately treated, although treatment guidelines are lacking, the prognosis is good and life-threatening complications may occur occasionally. During chorea/hemiballism, we recommend blood glucose and HbA1c evaluation. Further studies are needed to understand the pathogenesis