106 research outputs found
Design of dye-sensitized TiO2 materials for photocatalytic hydrogen production: light and shadow
Visible light-driven production of fuels and value-added chemicals is currently one of the most
intensely investigated research topics across various scientific disciplines, due to its potential to ease the
World\u2019s dependence on fossil fuels. In this perspective, we recapitulate some of the main features of dyesensitized
photocatalytic systems aimed at solar H2 production, focusing in particular on TiO2-based threecomponent
assemblies with organic sensitizers. Relevant aspects include the structural and electronic
properties of the sensitizers, the nature of the semiconductor and the hydrogen evolution catalysts, the role
of the sacrificial donor and the effect of the reaction parameters on H2 production rate and stability. Besides
presenting the most significant recent developments of the field, we also analyse some of its common
practices in terms of experimental design, laboratory procedures and data presentation, trying to highlight
their weaknesses and suggesting possible improvements. We then conclude with a short paragraph
discussing the possible future development of this exciting research area
Computational Design and Parametric Optimization Approach with Genetic Algorithms of an Innovative Concrete Shading Device System
Office buildings in contemporary architecture usually have a high value of window to wall ratio (WWR) determining transparent façade as the most important part of the building façade to control solar gains, thermal losses and visual comfort. Therefore, in order to fulfill strict National energy regulations and LEED requirements, façades require a proper balance between transparent and opaque or shaded surfaces to avoid overheating, optimizing daylighting aspects and outdoor perception. Concrete is usually used in building sector for primary structure or secondary structure of cladding solutions. With new concrete materials and innovative digital fabrication process is possible to rediscover concrete for high performance façade/shading solutions. The aim of this paper is the development of high performance concrete static shading system using computational design approach and its optimization, by genetic algorithms, based on several parameters such as radiation control, outdoor view and daylight indexes and energy performance. After the development of a geometry definition managed with a parametric modelling approach (Rhinoceros and Grasshopper), genetic algorithm optimization were used in order to define the openness's sizes and their cutting angle to minimize solar radiation entrance during year, maintaining outdoor view. The possible geometric alternatives were part of a sensitivity analysis with Radiance and Energy-plus engine to assess the shading system performance in terms of daylighting and energy use. In order to evaluate their performances a study case, a single office unit placed in Milan (Italy) was defined, considered with wall facing outdoors, having a WWR of 86%, and five surfaces adiabatic. The results shows that using this approach is possible to develop an effectiveness shading solution able to control radiation over the year and likewise guarantee a high performance regarding the outdoor perception and visual comfort
Polychlorinated Biphenyls and Semen Quality in Healthy Young Men Living in a Contaminated Area
Polychlorinated biphenyls (PCBs) are persistent organic pollutants and endocrine disruptors that have been implicated in potential damage to human semen. However, the studies conducted so far provide contrasting results. Our study aimed to investigate the associations between PCB serum and semen levels and semen quality in high school and university students living in a highly PCB-polluted area of Italy. Subjects with a normal body mass index who did not make daily use of tobacco, alcohol, drugs, or medication were selected. All participants provided a fasting blood and a semen sample. Gas chromatography-mass spectrometry was used to determine the concentrations of 26 PCB congeners. The concentrations of PCB functional groups and total PCBs were also computed. A total of 143 subjects (median age 20, range 18–22 years) were enrolled. The median total PCB concentrations were 3.85 ng/mL (range 3.43–4.56 ng/mL) and 0.29 ng/mL (range 0.26–0.32 ng/mL) in serum and semen, respectively. The analysis of the associations between sperm PCB concentration and semen parameters showed (a) negative associations between some PCB congeners, functional groups and total PCBs and sperm total motility; (b) negative associations of total PCBs with sperm normal morphology; and (c) no association of PCBs with sperm concentration. Subjects at the highest quartile of semen total PCB concentration had 19% and 23% mean reductions in total motility and normal morphology, respectively, compared to those at the lowest quartile. The analysis of the associations of serum PCB levels with sperm parameters yielded null or mixed (some positive, other negative) results. In conclusion, the present study provides evidence of a negative effect of some PCB congeners and total PCBs in semen on sperm motility and normal morphology. However, the associations between the concentration of serum and semen PCB congeners and functional groups and sperm quality parameters were inconsistent
An unusual cause of eosinophilic pleural effusion and migrating biliary stenosis: Strongyloides stercoralis infection in a young immunocompetent man
We present the case of a 33 year-old Italian man who came to our attention for epigastralgia associated with polyserositis (pleural and pericardial and peritoneal effusion with the involvement of the Douglas excavation), in the absence of a significant medical history. Laboratory analysis revealed exudative eosinophilic pleural effusion; serial imaging techniques showed a transient stenosis of the right hepatic duct and a subsequent stenosis of the left hepatic duct. After several negative sierological investigations, a positive antistrongyloides IgG antibodies titre rose suspicions of Strongyloides infection, which was confirmed by positive stool sample for parasite. Ivermectin-therapy was started and the patient’s fully recovered
Analisi della evoluzione delle tecnologie hardware per il calcolo scientifico
Gli esperimenti della fisica HEP avranno bisogno, nel prossimo decennio, di strumenti di calcolo di enorme potenza, che le tecnologie attuali non potranno soddisfare. Questo lavoro è un'analisi dell'evoluzione delle tecnologie di CPU, di storage e di rete, volta a valutare alcuni degli indicatori (prestazioni, consumi) su cui poter basare la progettazione di un centro di calcolo valida per i prossimi 10 anni. Previsioni sull'evoluzione tecnologica di tale durata sono facilmente soggette ad errori di valutazione anche macroscopici: roadmap valide solo per tre-quattro anni, inaspettati balzi tecnologici, imprevedibili mutamenti di andamento del mercato, possono facilmente cambiare o anche ribaltare previsioni così a lungo protratte nel futuro, ed invalidare estrapolazioni per quanto accurate. Ciononostante, un'analisi della situazione e di quello che oggi può essere detto in relazione all'evoluzione di queste tecnologie è un punto di partenza senza il quale non sarebbe possibile fare alcun tipo di ipotesi
Non-invasive estimation of in vivo optical properties and hemodynamic parameters of domestic animals: a preliminary study on horses, dogs, and sheep
Biosensors applied in veterinary medicine serve as a noninvasive method to determine the health status of animals and, indirectly, their level of welfare. Near infrared spectroscopy (NIRS) has been suggested as a technology with this application. This study presents preliminary in vivo time domain NIRS measurements of optical properties (absorption coefficient, reduced scattering coefficient, and differential pathlength factor) and hemodynamic parameters (concentration of oxygenated hemoglobin, deoxygenated hemoglobin, total hemoglobin, and tissue oxygen saturation) of tissue domestic animals, specifically of skeletal muscle (4 dogs and 6 horses) and head (4 dogs and 19 sheep). The results suggest that TD NIRS in vivo measurements on domestic animals are feasible, and reveal significant variations in the optical and hemodynamic properties among tissue types and species. In horses the different optical and hemodynamic properties of the measured muscles can be attributed to the presence of a thicker adipose layer over the muscle in the Longissimus Dorsi and in the Gluteus Superficialis as compared to the Triceps Brachii. In dogs the absorption coefficient is higher in the head (temporalis musculature) than in skeletal muscles. The smaller absorption coefficient for the head of the sheep as compared to the head of dogs may suggest that in sheep we are indeed reaching the brain cortex while in dog light penetration can be hindered by the strongly absorbing muscle covering the cranium
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
An in vivo screen identifies ependymoma oncogenes and tumor-suppressor genes
Cancers are characterized by non-random chromosome copy number alterations that presumably contain oncogenes and tumor-suppressor genes (TSGs). The affected loci are often large, making it difficult to pinpoint which genes are driving the cancer. Here we report a cross-species in vivo screen of 84 candidate oncogenes and 39 candidate TSGs, located within 28 recurrent chromosomal alterations in ependymoma. Through a series of mouse models, we validate eight new ependymoma oncogenes and ten new ependymoma TSGs that converge on a small number of cell functions, including vesicle trafficking, DNA modification and cholesterol biosynthesis, identifying these as potential new therapeutic targets.We are grateful to F.B. Gertler (Massachusetts Institute of Technology) and S. Gupton (University of North Carolina) for the generous gift of the VAMP7-phlorin construct and the staffs of the Hartwell Center for Bioinformatics and Biotechnology, the Small Animal Imaging Center, the Animal Resources Center, the Cell and Tissue Imaging Center, and the Flow Cytometry and Cell Sorting Shared Resource at St. Jude Children's Research Hospital for technical assistance. This work was supported by grants from the US National Institutes of Health (R01CA129541, P01CA96832 and P30CA021765, R.J.G.), by the Collaborative Ependymoma Research Network (CERN) and by the American Lebanese Syrian Associated Charities (ALSAC)
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
- …